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  1. Right Hemisphere and Left Hemisphere: Pedagogical Implications for CSL Reading.

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    Mickel, Stanley L.

    Students can be taught to read Chinese more efficiently and accurately by using the specific capabilities of the right and left hemispheres of the brain. The right hemisphere is the site of image and pattern recognition, and students can be taught to use those capacities to process individual characters efficiently by watching for the element of…

  2. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke

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    Xing, Shihui; Lacey, Elizabeth H.; Skipper-Kallal, Laura M.; Jiang, Xiong; Harris-Love, Michelle L.; Zeng, Jinsheng

    2016-01-01

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor’s lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion–symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  3. Caffeine improves left hemisphere processing of positive words.

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    Kuchinke, Lars; Lux, Vanessa

    2012-01-01

    A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

  4. Caffeine improves left hemisphere processing of positive words.

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    Lars Kuchinke

    Full Text Available A positivity advantage is known in emotional word recognition in that positive words are consistently processed faster and with fewer errors compared to emotionally neutral words. A similar advantage is not evident for negative words. Results of divided visual field studies, where stimuli are presented in either the left or right visual field and are initially processed by the contra-lateral brain hemisphere, point to a specificity of the language-dominant left hemisphere. The present study examined this effect by showing that the intake of caffeine further enhanced the recognition performance of positive, but not negative or neutral stimuli compared to a placebo control group. Because this effect was only present in the right visual field/left hemisphere condition, and based on the close link between caffeine intake and dopaminergic transmission, this result points to a dopaminergic explanation of the positivity advantage in emotional word recognition.

  5. Apraxia and spatial inattention dissociate in left hemisphere stroke.

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    Timpert, David C; Weiss, Peter H; Vossel, Simone; Dovern, Anna; Fink, Gereon R

    2015-10-01

    Theories of lateralized cognitive functions propose a dominance of the left hemisphere for motor control and of the right hemisphere for spatial attention. Accordingly, spatial attention deficits (e.g., neglect) are more frequently observed after right-hemispheric stroke, whereas apraxia is a common consequence of left-hemispheric stroke. Clinical reports of spatial attentional deficits after left hemisphere (LH) stroke also exist, but are often neglected. By applying parallel analysis (PA) and voxel-based lesion-symptom mapping (VLSM) to data from a comprehensive neuropsychological assessment of 74 LH stroke patients, we here systematically investigate the relationship between spatial inattention and apraxia and their neural bases. PA revealed that apraxic (and language comprehension) deficits loaded on one common component, while deficits in attention tests were explained by another independent component. Statistical lesion analyses with the individual component scores showed that apraxic (and language comprehension) deficits were significantly associated with lesions of the left superior longitudinal fascicle (SLF). Data suggest that in LH stroke spatial attention deficits dissociate from apraxic (and language comprehension) deficits. These findings contribute to models of lateralised cognitive functions in the human brain. Moreover, our findings strongly suggest that LH stroke patients should be assessed systematically for spatial attention deficits so that these can be included in their rehabilitation regime. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Reorganization of syntactic processing following left-hemisphere brain damage: does right-hemisphere activity preserve function?

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    Tyler, Lorraine K; Wright, Paul; Randall, Billi; Marslen-Wilson, William D; Stamatakis, Emmanuel A

    2010-11-01

    The extent to which the human brain shows evidence of functional plasticity across the lifespan has been addressed in the context of pathological brain changes and, more recently, of the changes that take place during healthy ageing. Here we examine the potential for plasticity by asking whether a strongly left-lateralized system can successfully reorganize to the right-hemisphere following left-hemisphere brain damage. To do this, we focus on syntax, a key linguistic function considered to be strongly left-lateralized, combining measures of tissue integrity, neural activation and behavioural performance. In a functional neuroimaging study participants heard spoken sentences that differentially loaded on syntactic and semantic information. While healthy controls activated a left-hemisphere network of correlated activity including Brodmann areas 45/47 and posterior middle temporal gyrus during syntactic processing, patients activated Brodmann areas 45/47 bilaterally and right middle temporal gyrus. However, voxel-based morphometry analyses showed that only tissue integrity in left Brodmann areas 45/47 was correlated with activity and performance; poor tissue integrity in left Brodmann area 45 was associated with reduced functional activity and increased syntactic deficits. Activity in the right-hemisphere was not correlated with damage in the left-hemisphere or with performance. Reduced neural integrity in the left-hemisphere through brain damage or healthy ageing results in increased right-hemisphere activation in homologous regions to those left-hemisphere regions typically involved in the young. However, these regions do not support the same linguistic functions as those in the left-hemisphere and only indirectly contribute to preserved syntactic capacity. This establishes the unique role of the left hemisphere in syntax, a core component in human language.

  7. Why Are the Right and Left Hemisphere Conceptual Representations Different?

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    Guido Gainotti

    2014-01-01

    Full Text Available The present survey develops a previous position paper, in which I suggested that the multimodal semantic impairment observed in advanced stages of semantic dementia is due to the joint disruption of pictorial and verbal representations, subtended by the right and left anterior temporal lobes, rather than to the loss of a unitary, amodal semantic system. The main goals of the present review are (a to survey a larger set of data, in order to confirm the differences in conceptual representations at the level of the right and left hemispheres, (b to examine if language-mediated information plays a greater role in left hemisphere semantic knowledge than sensory-motor information in right hemisphere conceptual knowledge, and (c to discuss the models that could explain both the differences in conceptual representations at the hemispheric level and the prevalence of the left hemisphere language-mediated semantic knowledge over the right hemisphere perceptually based conceptual representations.

  8. [Difficulties in face identification after lesion in the left hemisphere].

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    Verstichel, P; Chia, L

    1999-11-01

    A 82 year-old right-handed man, without any intellectual impairment, suffered from an acute neurological deficit consisting in letter-by-letter reading, right superior quadrant hemianopia with achromatopia in the lower quadrant, and anomia. Cerebral MRI showed an infarct involving the ventral structures of the left hemisphere sparing the splenium of the corpus callosum and the thalamus. Neuropsychological examination revealed that the patient easily identified the objects, the animals and the famous places he could not name: his comments attested normal visual recognition. Conversely, when he was presented with famous faces, he always had a strong feeling of familiarity, but could not provide accurate information about the corresponding individual. Biographic information about personalities was not impaired in the semantic-biographic store, because it could be accessed from the names. Activation of face recognition units (where the visual description provided by the structural encoding and the stored sets of descriptions of familiar faces are compared), was effective, since the patient could distinguish famous faces from unknown ones. In a modular-sequential model of face recognition, this deficit is interpreted as a disconnection between face recognition units and person identity nodes (which are considered to contain semantic-biographic information about individuals). This kind of disturbance differs from classic prosopagnosia in which, characteristically, the patients are unable to experience a feeling of familiarity when viewing famous faces, and to perform a categorization between famous and unknown faces. Right hemisphere has a preponderant role in structural analysis of faces and in activation of face recognition units. The integrity of this hemisphere in this patient could explain the preservation of these two steps of processing. Left-hemisphere specific function in facial recognition enabled access to semantic-biographic store in a conscious, verbal and

  9. Developmental dyslexia: dysfunction of a left hemisphere reading network

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    Fabio eRichlan

    2012-05-01

    Full Text Available This mini-review summarizes and integrates findings from recent meta-analyses and original neuroimaging studies on functional brain abnormalities in dyslexic readers. Surprisingly, there is little empirical support for the standard neuroanatomical model of developmental dyslexia, which localizes the primary phonological decoding deficit in left temporo-parietal regions. Rather, recent evidence points to a dysfunction of a left hemisphere reading network, which includes occipito-temporal, inferior frontal, and inferior parietal regions.

  10. Testing the Language of German Cerebral Palsy Patients with Right Hemispheric Language Organization after Early Left Hemispheric Damage

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    Schwilling, Eleonore; Krageloh-Mann, Ingeborg; Konietzko, Andreas; Winkler, Susanne; Lidzba, Karen

    2012-01-01

    Language functions are generally represented in the left cerebral hemisphere. After early (prenatally acquired or perinatally acquired) left hemispheric brain damage language functions may be salvaged by reorganization into the right hemisphere. This is different from brain lesions acquired in adulthood which normally lead to aphasia. Right…

  11. Lesion characteristics driving right-hemispheric language reorganization in congenital left-hemispheric brain damage.

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    Lidzba, Karen; de Haan, Bianca; Wilke, Marko; Krägeloh-Mann, Ingeborg; Staudt, Martin

    2017-10-01

    Pre- or perinatally acquired ("congenital") left-hemispheric brain lesions can be compensated for by reorganizing language into homotopic brain regions in the right hemisphere. Language comprehension may be hemispherically dissociated from language production. We investigated the lesion characteristics driving inter-hemispheric reorganization of language comprehension and language production in 19 patients (7-32years; eight females) with congenital left-hemispheric brain lesions (periventricular lesions [n=11] and middle cerebral artery infarctions [n=8]) by fMRI. 16/17 patients demonstrated reorganized language production, while 7/19 patients had reorganized language comprehension. Lesions to the insular cortex and the temporo-parietal junction (predominantly supramarginal gyrus) were significantly more common in patients in whom both, language production and comprehension were reorganized. These areas belong to the dorsal stream of the language network, participating in the auditory-motor integration of language. Our data suggest that the integrity of this stream might be crucial for a normal left-lateralized language development. Copyright © 2017. Published by Elsevier Inc.

  12. Hemispheric lateralization in an analysis of speech sounds. Left hemisphere dominance replicated in Japanese subjects.

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    Koyama, S; Gunji, A; Yabe, H; Oiwa, S; Akahane-Yamada, R; Kakigi, R; Näätänen, R

    2000-09-01

    Evoked magnetic responses to speech sounds [R. Näätänen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M. Vainio, P. Alku, R.J. Ilmoniemi, A. Luuk, J. Allik, J. Sinkkonen and K. Alho, Language-specific phoneme representations revealed by electric and magnetic brain responses. Nature, 385 (1997) 432-434.] were recorded from 13 Japanese subjects (right-handed). Infrequently presented vowels ([o]) among repetitive vowels ([e]) elicited the magnetic counterpart of mismatch negativity, MMNm (Bilateral, nine subjects; Left hemisphere alone, three subjects; Right hemisphere alone, one subject). The estimated source of the MMNm was stronger in the left than in the right auditory cortex. The sources were located posteriorly in the left than in the right auditory cortex. These findings are consistent with the results obtained in Finnish [R. Näätänen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M.Vainio, P.Alku, R.J. Ilmoniemi, A. Luuk, J. Allik, J. Sinkkonen and K. Alho, Language-specific phoneme representations revealed by electric and magnetic brain responses. Nature, 385 (1997) 432-434.][T. Rinne, K. Alho, P. Alku, M. Holi, J. Sinkkonen, J. Virtanen, O. Bertrand and R. Näätänen, Analysis of speech sounds is left-hemisphere predominant at 100-150 ms after sound onset. Neuroreport, 10 (1999) 1113-1117.] and English [K. Alho, J.F. Connolly, M. Cheour, A. Lehtokoski, M. Huotilainen, J. Virtanen, R. Aulanko and R.J. Ilmoniemi, Hemispheric lateralization in preattentive processing of speech sounds. Neurosci. Lett., 258 (1998) 9-12.] subjects. Instead of the P1m observed in Finnish [M. Tervaniemi, A. Kujala, K. Alho, J. Virtanen, R.J. Ilmoniemi and R. Näätänen, Functional specialization of the human auditory cortex in processing phonetic and musical sounds: A magnetoencephalographic (MEG) study. Neuroimage, 9 (1999) 330-336.] and English [K. Alho, J. F. Connolly, M. Cheour, A. Lehtokoski, M. Huotilainen, J. Virtanen, R. Aulanko

  13. Right-ear precedence and vocal emotion contagion: The role of the left hemisphere.

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    Schepman, Astrid; Rodway, Paul; Cornmell, Louise; Smith, Bethany; de Sa, Sabrina Lauren; Borwick, Ciara; Belfon-Thompson, Elisha

    2018-05-01

    Much evidence suggests that the processing of emotions is lateralized to the right hemisphere of the brain. However, under some circumstances the left hemisphere might play a role, particularly for positive emotions and emotional experiences. We explored whether emotion contagion was right-lateralized, lateralized valence-specifically, or potentially left-lateralized. In two experiments, right-handed female listeners rated to what extent emotionally intoned pseudo-sentences evoked target emotions in them. These sound stimuli had a 7 ms ear lead in the left or right channel, leading to stronger stimulation of the contralateral hemisphere. In both experiments, the results revealed that right ear lead stimuli received subtly but significantly higher evocation scores, suggesting a left hemisphere dominance for emotion contagion. A control experiment using an emotion identification task showed no effect of ear lead. The findings are discussed in relation to prior findings that have linked the processing of emotional prosody to left-hemisphere brain regions that regulate emotions, control orofacial musculature, are involved in affective empathy processing areas, or have an affinity for processing emotions socially. Future work is needed to eliminate alternative interpretations and understand the mechanisms involved. Our novel binaural asynchrony method may be useful in future work in auditory laterality.

  14. Othello syndrome in a patient with two left hemispheric tumors

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    Po-Kuan Yeh

    2016-01-01

    Full Text Available We report a case of a patient with Othello syndrome caused by two left hemispheric tumors. This 50-year-old female had experienced seizures for 10 years and developed manic-like symptoms, delusions of jealousy, persecution and being watched, auditory hallucinations, irritable mood, and violent and disorganized behavior for the past 3 years. Brain imaging studies revealed two left frontal tumors, the larger of which was causing a mass effect. The delusions of jealousy in Othello syndrome resolved after removing the larger tumor, and the other psychiatric symptoms improved after treatment with psychotropic medications. This report aims to raise awareness of Othello syndrome related to disruptions in cortico-subcortical connections in the left orbitofrontal region. Timely surgical treatment may prevent associated psychiatric comorbidities and increase the likelihood of a good outcome.

  15. Testing the language of German cerebral palsy patients with right hemispheric language organization after early left hemispheric damage.

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    Schwilling, Eleonore; Krägeloh-Mann, Ingeborg; Konietzko, Andreas; Winkler, Susanne; Lidzba, Karen

    2012-02-01

    Language functions are generally represented in the left cerebral hemisphere. After early (prenatally acquired or perinatally acquired) left hemispheric brain damage language functions may be salvaged by reorganization into the right hemisphere. This is different from brain lesions acquired in adulthood which normally lead to aphasia. Right hemispheric reorganized language (RL) is not associated with obvious language deficits. In this pilot study we compared a group of German-speaking patients with left hemispheric brain damage and RL with a group of matched healthy controls. The novel combination of reliable language lateralization as assessed by neuroimaging (functional magnetic resonance imaging) and specific linguistic tasks revealed significant differences between patients with RL and healthy controls in both language comprehension and production. Our results provide evidence for the hypothesis that RL is significantly different from normal left hemispheric language. This knowledge can be used to improve counselling of parents and to develop specific therapeutic approaches.

  16. Beyond Hemispheric Dominance: Brain Regions Underlying the Joint Lateralization of Language and Arithmetic to the Left Hemisphere

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    Pinel, Philippe; Dehaene, Stanislas

    2010-01-01

    Language and arithmetic are both lateralized to the left hemisphere in the majority of right-handed adults. Yet, does this similar lateralization reflect a single overall constraint of brain organization, such an overall "dominance" of the left hemisphere for all linguistic and symbolic operations? Is it related to the lateralization of specific…

  17. Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes.

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    Donkervoort, M; Dekker, J; van den Ende, E; Stehmann-Saris, J C; Deelman, B G

    2000-04-01

    To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). A short questionnaire on general patient characteristics and stroke-related aspects was completed by occupational therapists for every left hemisphere stroke patient they treated. A diagnosis of apraxia or nonapraxia was made in every patient, on the basis of a set of clinical criteria. The prevalence of apraxia among 492 first left hemisphere stroke patients in rehabilitation centres was 28% (96/338) and in nursing homes 37% (57/154). No relationship was found between the prevalence of apraxia and age, gender or type of stroke (haemorrhage or infarct). This study shows that approximately one-third of left hemisphere stroke patients has apraxia.

  18. Phonotactic awareness deficit following left-hemisphere stroke

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    Maryam Ghaleh

    2015-04-01

    Likert-type scale responses were z-transformed and coded accurate for positive z-values in condition 3 and negative z-values in condition 1 trials. Accuracy was analyzed using binomial mixed effects models and z-transformed scale responses were analyzed using linear mixed effects models. For both analyses, the fixed effects of stimulus, trial number, group (patient/control, education, age, response time, phonotactic regularity (1/3, and gender were examined along with all relevant interactions. Random effects for participant and stimuli as well as random slopes were also included. Model fitting was performed in a backward-stepwise iterative fashion, followed by forward fitting of maximal random effects structure. Models were evaluated by model fitness comparisons using Akaike Information Criterion and Bayesian Information Criterion. Accuracy analysis revealed that healthy participants were significantly more accurate than patients [β = 0.47, p<0.001] in Englishness rating. Scale response analysis revealed a significant effect of phonotactic regularity [β = 1.65, p<0.0001] indicating that participants were sensitive to phonotactic regularity differences among non-words. However, the significant interaction of group and phonotactic regularity [β = -0.5, p= 0.02] further demonstrated that, compared to healthy adults, patients were less able to recognize the phonotactic regularity differences between non-words. Results suggest that left-hemisphere lesions cause impaired phonotactic processing and that the left hemisphere might be necessary for phonotactic awareness. These preliminary findings will be followed up by further analyses investigating the interactions between phonotactic processing and participants’ scores on other linguistic/cognitive tasks as well as lesion-symptom mapping.

  19. Auditory Processing after Early Left Hemisphere Injury: A Case Report

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    Cristina Ferraz Borges Murphy

    2017-05-01

    Full Text Available Few studies have addressed the long-term outcomes of early brain injury, especially after hemorrhagic stroke. This is the first study to report a case of acquired auditory processing disorder in a 10-year-old child who had a severe left hemorrhagic cerebral infarction at 13 months of age, compromising nearly all of the left temporal lobe. This case, therefore, is an excellent and rare opportunity to investigate the presence of neural plasticity of central auditory system in a developing brain followed severe brain damage. After assuring normal functioning of the peripheral auditory system, a series of behavioral auditory processing tests was applied in dichotic and monaural listening conditions and with verbal and non-verbal stimuli. For all verbal dichotic tasks (dichotic digits, competing words, and sentences tests, good performance on the left ear, especially for Dichotic digits test (100%, and zero performance on the right ear were observed. For monaural low-redundancy tests, the patient also exhibited good performance for auditory figure-ground and time-compressed sentences tests in the left ear. In the right ear, a very poor performance was observed, but slightly better than the same in Dichotic tasks. Impaired performance was also observed in the LiSN test in terms of spatial advantage and, for the Pitch Pattern Sequence test, the only non-verbal test applied, the patient had performance within the normal range in both ears. These results are interpreted taking into consideration the anatomical location of stroke lesion and also the influence of hemispheric specialization for language on auditory processing performance.

  20. Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset.

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    Raschle, Nora Maria; Zuk, Jennifer; Gaab, Nadine

    2012-02-07

    Individuals with developmental dyslexia (DD) show a disruption in posterior left-hemispheric neural networks during phonological processing. Additionally, compensatory mechanisms in children and adults with DD have been located within frontal brain areas. However, it remains unclear when and how differences in posterior left-hemispheric networks manifest and whether compensatory mechanisms have already started to develop in the prereading brain. Here we investigate functional networks during phonological processing in 36 prereading children with a familial risk for DD (n = 18, average age = 66.50 mo) compared with age and IQ-matched controls (n = 18; average age = 65.61 mo). Functional neuroimaging results reveal reduced activation in prereading children with a family-history of DD (FHD(+)), compared with those without (FHD(-)), in bilateral occipitotemporal and left temporoparietal brain regions. This finding corresponds to previously identified hypoactivations in left hemispheric posterior brain regions for school-aged children and adults with a diagnosis of DD. Furthermore, left occipitotemporal and temporoparietal brain activity correlates positively with prereading skills in both groups. Our results suggest that differences in neural correlates of phonological processing in individuals with DD are not a result of reading failure, but are present before literacy acquisition starts. Additionally, no hyperactivation in frontal brain regions was observed, suggesting that compensatory mechanisms for reading failure are not yet present. Future longitudinal studies are needed to determine whether the identified differences may serve as neural premarkers for the early identification of children at risk for DD.

  1. The course of apraxia and ADL functioning in left hemisphere stroke patients treated in rehabilitation centres and nursing homes.

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    Donkervoort, M.; Dekker, J.; Deelman, B.

    2006-01-01

    OBJECTIVE: To study the course of apraxia and daily life functioning (ADL) in left hemisphere stroke patients with apraxia. DESIGN: Prospective cohort study. SETTING: Rehabilitation centres and nursing homes. SUBJECTS: One hundred and eight left hemisphere stroke patients with apraxia, hospitalized in rehabilitation centres and nursing homes. MEASURES: ADL-observations, Barthel ADL Index, Apraxia Test, Motricity Index. RESULTS: During the study period of 20 weeks, patients showed small improv...

  2. The effects of left and right monocular viewing on hemispheric activation.

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    Wang, Chao; Burtis, D Brandon; Ding, Mingzhou; Mo, Jue; Williamson, John B; Heilman, Kenneth M

    2018-03-01

    Prior research has revealed that whereas activation of the left hemisphere primarily increases the activity of the parasympathetic division of the autonomic nervous system, right-hemisphere activation increases the activity of the sympathetic division. In addition, each hemisphere primarily receives retinocollicular projections from the contralateral eye. A prior study reported that pupillary dilation was greater with left- than with right-eye monocular viewing. The goal of this study was to test the alternative hypotheses that this asymmetric pupil dilation with left-eye viewing was induced by activation of the right-hemispheric-mediated sympathetic activity, versus a reduction of left-hemisphere-mediated parasympathetic activity. Thus, this study was designed to learn whether there are changes in hemispheric activation, as measured by alteration of spontaneous alpha activity, during right versus left monocular viewing. High-density electroencephalography (EEG) was recorded from healthy participants viewing a crosshair with their right, left, or both eyes. There was a significantly less alpha power over the right hemisphere's parietal-occipital area with left and binocular viewing than with right-eye monocular viewing. The greater relative reduction of right-hemisphere alpha activity during left than during right monocular viewing provides further evidence that left-eye viewing induces greater increase in right-hemisphere activation than does right-eye viewing.

  3. Reorganization of the Cerebro-Cerebellar Network of Language Production in Patients with Congenital Left-Hemispheric Brain Lesions

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    Lidzba, K.; Wilke, M.; Staudt, M.; Krageloh-Mann, I.; Grodd, W.

    2008-01-01

    Patients with congenital lesions of the left cerebral hemisphere may reorganize language functions into the right hemisphere. In these patients, language production is represented homotopically to the left-hemispheric language areas. We studied cerebellar activation in five patients with congenital lesions of the left cerebral hemisphere to assess…

  4. Efficacy of strategy training in left hemisphere stroke patients with apraxia : A randomised clinical trial

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    Donkervoort, M; Dekker, J; Stehmann-Saris, FC; Deelman, B. G.

    2001-01-01

    The objective of the present study was to determine in a controlled study the efficacy of strategy training in left hemisphere stroke patients with apraxia. A total of 113 left hemisphere stroke patients with apraxia were randomly assigned to two treatment groups; (1) strategy training integrated

  5. Cognitive alterations in motor imagery process after left hemispheric ischemic stroke.

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    Jing Yan

    Full Text Available BACKGROUND: Motor imagery training is a promising rehabilitation strategy for stroke patients. However, few studies had focused on the neural mechanisms in time course of its cognitive process. This study investigated the cognitive alterations after left hemispheric ischemic stroke during motor imagery task. METHODOLOGY/PRINCIPAL FINDINGS: Eleven patients with ischemic stroke in left hemisphere and eleven age-matched control subjects participated in mental rotation task (MRT of hand pictures. Behavior performance, event-related potential (ERP and event-related (desynchronization (ERD/ERS in beta band were analyzed to investigate the cortical activation. We found that: (1 The response time increased with orientation angles in both groups, called "angle effect", however, stoke patients' responses were impaired with significantly longer response time and lower accuracy rate; (2 In early visual perceptual cognitive process, stroke patients showed hypo-activations in frontal and central brain areas in aspects of both P200 and ERD; (3 During mental rotation process, P300 amplitude in control subjects decreased while angle increased, called "amplitude modulation effect", which was not observed in stroke patients. Spatially, patients showed significant lateralization of P300 with activation only in contralesional (right parietal cortex while control subjects showed P300 in both parietal lobes. Stroke patients also showed an overall cortical hypo-activation of ERD during this sub-stage; (4 In the response sub-stage, control subjects showed higher ERD values with more activated cortical areas particularly in the right hemisphere while angle increased, named "angle effect", which was not observed in stroke patients. In addition, stroke patients showed significant lower ERD for affected hand (right response than that for unaffected hand. CONCLUSIONS/SIGNIFICANCE: Cortical activation was altered differently in each cognitive sub-stage of motor imagery after

  6. Ipsilateral deficits in 1-handed shoe tying after left or right hemisphere stroke.

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    Poole, Janet L; Sadek, Joseph; Haaland, Kathleen Y

    2009-10-01

    Poole JL, Sadek J, Haaland KY. Ipsilateral deficits in 1-handed shoe tying after left or right hemisphere stroke. To examine 1-handed shoe tying performance and whether cognitive deficits more associated with left or right hemisphere damage differentially affect it after unilateral stroke. Observational cohort comparing ipsilesional shoe tying, spatial and language skills, and limb praxis. Primary care Veterans Affairs and private medical center. Not applicable. Volunteer right-handed sample of adults with left or right hemisphere damage and healthy demographically matched adults. The number of correct trials and the total time to complete 10 trials tying a shoe using the 1-handed method. Both stroke groups had fewer correct trials and were significantly slower tying the shoe than the control group. Spatial skills predicted accuracy and speed after right hemisphere damage. After left hemisphere damage, accuracy was predicted by spatial skills and limb praxis, while speed was predicted by limb praxis only. Ipsilesional shoe tying is similarly impaired after left or right hemisphere damage, but for different reasons. Spatial deficits had a greater influence after right hemisphere damage, and limb apraxia had a greater influence after left hemisphere damage. Language deficits did not affect performance, indicating that aphasia does not preclude using this therapy approach. These results suggest that rehabilitation professionals should consider assessment of limb apraxia and ipsilesional skill training in the performance of everyday tasks.

  7. Cerebral hemispheric blood flow velocity differences in left- and right- handers: functional trans-cranial Doppler ultrasonography

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    Sikaroodi H

    2009-12-01

    dominance was observed in 43.3% of right handers and 46.7% of left handers. Left hemispheric dominance was observed in 56.7% of right handers and 53.3% of left handers. Our results showed no significant right hemispheric language dominance in left handed subjects."n"nConclusion: This study does not show significant difference in hemispheric language dominance between right and left handers, using functional TCD

  8. Left-hemisphere activation is associated with enhanced vocal pitch error detection in musicians with absolute pitch.

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    Behroozmand, Roozbeh; Ibrahim, Nadine; Korzyukov, Oleg; Robin, Donald A; Larson, Charles R

    2014-02-01

    The ability to process auditory feedback for vocal pitch control is crucial during speaking and singing. Previous studies have suggested that musicians with absolute pitch (AP) develop specialized left-hemisphere mechanisms for pitch processing. The present study adopted an auditory feedback pitch perturbation paradigm combined with ERP recordings to test the hypothesis whether the neural mechanisms of the left-hemisphere enhance vocal pitch error detection and control in AP musicians compared with relative pitch (RP) musicians and non-musicians (NM). Results showed a stronger N1 response to pitch-shifted voice feedback in the right-hemisphere for both AP and RP musicians compared with the NM group. However, the left-hemisphere P2 component activation was greater in AP and RP musicians compared with NMs and also for the AP compared with RP musicians. The NM group was slower in generating compensatory vocal reactions to feedback pitch perturbation compared with musicians, and they failed to re-adjust their vocal pitch after the feedback perturbation was removed. These findings suggest that in the earlier stages of cortical neural processing, the right hemisphere is more active in musicians for detecting pitch changes in voice feedback. In the later stages, the left-hemisphere is more active during the processing of auditory feedback for vocal motor control and seems to involve specialized mechanisms that facilitate pitch processing in the AP compared with RP musicians. These findings indicate that the left hemisphere mechanisms of AP ability are associated with improved auditory feedback pitch processing during vocal pitch control in tasks such as speaking or singing. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. A Test of Some Models of Hemispheric Speech Organization in the Left- and Right-Handed.

    Science.gov (United States)

    Satz, Paul

    1979-01-01

    A new method generates specific predictions concerning the expected frequencies of aphasia after unilateral injury to the brain in the left- and right-handed. These predictions are then compared with the observed data for all known studies between 1935 and 1973 to derive the best-fitting model of hemispheric speech lateralization in the left- and…

  10. Moral judgement by the disconnected left and right cerebral hemispheres: a split-brain investigation.

    Science.gov (United States)

    Steckler, Conor M; Hamlin, J Kiley; Miller, Michael B; King, Danielle; Kingstone, Alan

    2017-07-01

    Owing to the hemispheric isolation resulting from a severed corpus callosum, research on split-brain patients can help elucidate the brain regions necessary and sufficient for moral judgement. Notably, typically developing adults heavily weight the intentions underlying others' moral actions, placing greater importance on valenced intentions versus outcomes when assigning praise and blame. Prioritization of intent in moral judgements may depend on neural activity in the right hemisphere's temporoparietal junction, an area implicated in reasoning about mental states. To date, split-brain research has found that the right hemisphere is necessary for intent-based moral judgement. When testing the left hemisphere using linguistically based moral vignettes, split-brain patients evaluate actions based on outcomes, not intentions. Because the right hemisphere has limited language ability relative to the left, and morality paradigms to date have involved significant linguistic demands, it is currently unknown whether the right hemisphere alone generates intent-based judgements. Here we use nonlinguistic morality plays with split-brain patient J.W. to examine the moral judgements of the disconnected right hemisphere, demonstrating a clear focus on intent. This finding indicates that the right hemisphere is not only necessary but also sufficient for intent-based moral judgement, advancing research into the neural systems supporting the moral sense.

  11. Left hemisphere structural connectivity abnormality in pediatric hydrocephalus patients following surgery

    Directory of Open Access Journals (Sweden)

    Weihong Yuan

    2016-01-01

    Full Text Available Neuroimaging research in surgically treated pediatric hydrocephalus patients remains challenging due to the artifact caused by programmable shunt. Our previous study has demonstrated significant alterations in the whole brain white matter structural connectivity based on diffusion tensor imaging (DTI and graph theoretical analysis in children with hydrocephalus prior to surgery or in surgically treated children without programmable shunts. This study seeks to investigate the impact of brain injury on the topological features in the left hemisphere, contratelateral to the shunt placement, which will avoid the influence of shunt artifacts and makes further group comparisons feasible for children with programmable shunt valves. Three groups of children (34 in the control group, 12 in the 3-month post-surgery group, and 24 in the 12-month post-surgery group, age between 1 and 18 years were included in the study. The structural connectivity data processing and analysis were performed based on DTI and graph theoretical analysis. Specific procedures were revised to include only left brain imaging data in normalization, parcellation, and fiber counting from DTI tractography. Our results showed that, when compared to controls, children with hydrocephalus in both the 3-month and 12-month post-surgery groups had significantly lower normalized clustering coefficient, lower small-worldness, and higher global efficiency (all p < 0.05, corrected. At a regional level, both patient groups showed significant alteration in one or more regional connectivity measures in a series of brain regions in the left hemisphere (8 and 10 regions in the 3-month post-surgery and the 12-month post-surgery group, respectively, all p < 0.05, corrected. No significant correlation was found between any of the global or regional measures and the contemporaneous neuropsychological outcomes [the General Adaptive Composite (GAC from the Adaptive Behavior Assessment System, Second

  12. Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes.

    OpenAIRE

    Donkervoort, M.; Dekker, J.; Ende, E. van den; Stehmann-Saris, J.C.; Deelman, B.G.

    2000-01-01

    OBJECTIVE: To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. SUBJECTS: Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). MEASURES: A short questionnaire on general patient characteristics and stroke-related aspects was completed by occupational therapists for every left hemisphere stroke patient they treated. A diagnosis of apraxia or nonapraxia was ...

  13. You may now kiss the bride: Interpretation of social situations by individuals with right or left hemisphere injury.

    Science.gov (United States)

    Baldo, Juliana V; Kacinik, Natalie A; Moncrief, Amber; Beghin, Francesca; Dronkers, Nina F

    2016-01-08

    While left hemisphere damage (LHD) has been clearly shown to cause a range of language impairments, patients with right hemisphere damage (RHD) also exhibit communication deficits, such as difficulties processing prosody, discourse, and social contexts. In the current study, individuals with RHD and LHD were directly compared on their ability to interpret what a character in a cartoon might be saying or thinking, in order to better understand the relative role of the right and left hemisphere in social communication. The cartoon stimuli were manipulated so as to elicit more or less formulaic responses (e.g., a scene of a couple being married by a priest vs. a scene of two people talking, respectively). Participants' responses were scored by blind raters on how appropriately they captured the gist of the social situation, as well as how formulaic and typical their responses were. Results showed that RHD individuals' responses were rated as significantly less appropriate than controls and were also significantly less typical than controls and individuals with LHD. Individuals with RHD produced a numerically lower proportion of formulaic expressions than controls, but this difference was only a trend. Counter to prediction, the pattern of performance across participant groups was not affected by how constrained/formulaic the social situation was. The current findings expand our understanding of the roles that the right and left hemispheres play in social processing and communication and have implications for the potential treatment of social communication deficits in individuals with RHD. Published by Elsevier Ltd.

  14. Opposed Left and Right Brain Hemisphere Contributions to Sexual Drive: A Multiple Lesion Case Analysis

    Directory of Open Access Journals (Sweden)

    Claude M. J. Braun

    2003-01-01

    Full Text Available Brain topographical studies of normal men have have shown that sexual excitation is asymmetric in the brain hemispheres. Group studies of patients with unilateral epileptic foci and other studies of patients with unilateral brain lesions have come to the same conclusion. The present study reviewed previously published single case reports of patients with frank hypo or hypersexuality subsequent to a unilateral brain lesion. Hyposexual patients tended to have left hemisphere lesions (primarily of the temporal lobe, and hypersexual patients tended to have right hemisphere lesions (primarily of the temporal lobe (p < 0.05. We interpret this double dissociation as part of a more general phenomenon of psychic tone similarly dissociated with regard to hemispheric control, including mood, psychomotor baseline, speech rate, and even immunity. The behavioral significance of this psychic tone is to modulate approach versus avoidance behavior.

  15. Mental Number Line Disruption in a Right-Neglect Patient after a Left-Hemisphere Stroke

    Science.gov (United States)

    Pia, Lorenzo; Corazzini, Luca Latini; Folegatti, Alessia; Gindri, Patrizia; Cauda, Franco

    2009-01-01

    A right-neglect patient with focal left-hemisphere damage to the posterior superior parietal lobe was assessed for numerical knowledge and tested on the bisection of numerical intervals and visual lines. The semantic and verbal knowledge of numbers was preserved, whereas the performance in numerical tasks that strongly emphasize the visuo-spatial…

  16. Left hemisphere EEG coherence in infancy predicts infant declarative pointing and preschool epistemic language.

    Science.gov (United States)

    Kühn-Popp, N; Kristen, S; Paulus, M; Meinhardt, J; Sodian, B

    2016-01-01

    Pointing plays a central role in preverbal communication. While imperative pointing aims at influencing another person's behavior, declarative gestures serve to convey epistemic information and to share interest in an object. Further, the latter are hypothesized to be a precursor ability of epistemic language. So far, little is known about their underlying brain maturation processes. Therefore, the present study investigated the relation between brain maturation processes and the production of imperative and declarative motives as well as epistemic language in N = 32 infants. EEG coherence scores were measured at 14 months, imperative and declarative point production at 15 months and epistemic language at 48 months. Results of correlational analyses suggest distinct behavioral and neural patterns for imperative and declarative pointing, with declarative pointing being associated with the maturation of the left hemisphere. Further, EEG coherence measures of the left hemisphere at 14 months and declarative pointing at 15 months are related to individual differences in epistemic language skills at 48 months, independently of child IQ. In regression analyses, coherence measures of the left hemisphere prove to be the most important predictor of epistemic language skills. Thus, neural processes of the left hemisphere seem particularly relevant to social communication.

  17. Increased left hemisphere impairment in high-functioning autism: a tract based spatial statistics study.

    Science.gov (United States)

    Perkins, Thomas John; Stokes, Mark Andrew; McGillivray, Jane Anne; Mussap, Alexander Julien; Cox, Ivanna Anne; Maller, Jerome Joseph; Bittar, Richard Garth

    2014-11-30

    There is evidence emerging from Diffusion Tensor Imaging (DTI) research that autism spectrum disorders (ASD) are associated with greater impairment in the left hemisphere. Although this has been quantified with volumetric region of interest analyses, it has yet to be tested with white matter integrity analysis. In the present study, tract based spatial statistics was used to contrast white matter integrity of 12 participants with high-functioning autism or Aspergers syndrome (HFA/AS) with 12 typically developing individuals. Fractional Anisotropy (FA) was examined, in addition to axial, radial and mean diffusivity (AD, RD and MD). In the left hemisphere, participants with HFA/AS demonstrated significantly reduced FA in predominantly thalamic and fronto-parietal pathways and increased RD. Symmetry analyses confirmed that in the HFA/AS group, WM disturbance was significantly greater in the left compared to right hemisphere. These findings contribute to a growing body of literature suggestive of reduced FA in ASD, and provide preliminary evidence for RD impairments in the left hemisphere. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Multi-tasking uncovers right spatial neglect and extinction in chronic left-hemisphere stroke patients.

    Science.gov (United States)

    Blini, Elvio; Romeo, Zaira; Spironelli, Chiara; Pitteri, Marco; Meneghello, Francesca; Bonato, Mario; Zorzi, Marco

    2016-11-01

    Unilateral Spatial Neglect, the most dramatic manifestation of contralesional space unawareness, is a highly heterogeneous syndrome. The presence of neglect is related to core spatially lateralized deficits, but its severity is also modulated by several domain-general factors (such as alertness or sustained attention) and by task demands. We previously showed that a computer-based dual-task paradigm exploiting both lateralized and non-lateralized factors (i.e., attentional load/multitasking) better captures this complex scenario and exacerbates deficits for the contralesional space after right hemisphere damage. Here we asked whether multitasking would reveal contralesional spatial disorders in chronic left-hemisphere damaged (LHD) stroke patients, a population in which impaired spatial processing is thought to be uncommon. Ten consecutive LHD patients with no signs of right-sided neglect at standard neuropsychological testing performed a computerized spatial monitoring task with and without concurrent secondary tasks (i.e., multitasking). Severe contralesional (right) space unawareness emerged in most patients under attentional load in both the visual and auditory modalities. Multitasking affected the detection of contralesional stimuli both when presented concurrently with an ipsilesional one (i.e., extinction for bilateral targets) and when presented in isolation (i.e., left neglect for right-sided targets). No spatial bias emerged in a control group of healthy elderly participants, who performed at ceiling, as well as in a second control group composed of patients with Mild Cognitive Impairment. We conclude that the pathological spatial asymmetry in LHD patients cannot be attributed to a global reduction of cognitive resources but it is the consequence of unilateral brain damage. Clinical and theoretical implications of the load-dependent lack of awareness for contralesional hemispace following LHD are discussed. Copyright © 2016. Published by Elsevier Ltd.

  19. The course of apraxia and ADL functioning in left hemisphere stroke patients treated in rehabilitation centres and nursing homes.

    NARCIS (Netherlands)

    Donkervoort, M.; Dekker, J.; Deelman, B.

    2006-01-01

    OBJECTIVE: To study the course of apraxia and daily life functioning (ADL) in left hemisphere stroke patients with apraxia. DESIGN: Prospective cohort study. SETTING: Rehabilitation centres and nursing homes. SUBJECTS: One hundred and eight left hemisphere stroke patients with apraxia, hospitalized

  20. Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes

    NARCIS (Netherlands)

    Donkervoort, M; Dekker, J; van den Ende, E; Stehmann-Saris, J. C.; Deelman, B. G.

    Objective: To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. Subjects. Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). Measures: A short questionnaire on

  1. Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes.

    NARCIS (Netherlands)

    Donkervoort, M.; Dekker, J.; Ende, E. van den; Stehmann-Saris, J.C.; Deelman, B.G.

    2000-01-01

    OBJECTIVE: To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. SUBJECTS: Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). MEASURES: A short questionnaire on

  2. Left hemisphere structural connectivity abnormality in pediatric hydrocephalus patients following surgery.

    Science.gov (United States)

    Yuan, Weihong; Meller, Artur; Shimony, Joshua S; Nash, Tiffany; Jones, Blaise V; Holland, Scott K; Altaye, Mekibib; Barnard, Holly; Phillips, Jannel; Powell, Stephanie; McKinstry, Robert C; Limbrick, David D; Rajagopal, Akila; Mangano, Francesco T

    2016-01-01

    Neuroimaging research in surgically treated pediatric hydrocephalus patients remains challenging due to the artifact caused by programmable shunt. Our previous study has demonstrated significant alterations in the whole brain white matter structural connectivity based on diffusion tensor imaging (DTI) and graph theoretical analysis in children with hydrocephalus prior to surgery or in surgically treated children without programmable shunts. This study seeks to investigate the impact of brain injury on the topological features in the left hemisphere, contratelateral to the shunt placement, which will avoid the influence of shunt artifacts and makes further group comparisons feasible for children with programmable shunt valves. Three groups of children (34 in the control group, 12 in the 3-month post-surgery group, and 24 in the 12-month post-surgery group, age between 1 and 18 years) were included in the study. The structural connectivity data processing and analysis were performed based on DTI and graph theoretical analysis. Specific procedures were revised to include only left brain imaging data in normalization, parcellation, and fiber counting from DTI tractography. Our results showed that, when compared to controls, children with hydrocephalus in both the 3-month and 12-month post-surgery groups had significantly lower normalized clustering coefficient, lower small-worldness, and higher global efficiency (all p  hydrocephalus surgically treated with programmable shunts.

  3. Is a lone right hemisphere enough? Neurolinguistic architecture in a case with a very early left hemispherectomy.

    Science.gov (United States)

    Danelli, Laura; Cossu, Giuseppe; Berlingeri, Manuela; Bottini, Gabriella; Sberna, Maurizio; Paulesu, Eraldo

    2013-01-01

    We studied the linguistic profile and neurolinguistic organization of a 14-year-old adolescent (EB) who underwent a left hemispherectomy at the age of 2.5 years. After initial aphasia, his language skills recovered within 2 years, with the exception of some word finding problems. Over the years, the neuropsychological assessments showed that EB's language was near-to-normal, with the exception of lexical competence, which lagged slightly behind for both auditory and written language. Moreover, EB's accuracy and speed in both reading and writing words and non-words were within the normal range, whereas difficulties emerged in reading loan words and in tasks with homophones. EB's functional magnetic resonance imaging (fMRI) patterns for several linguistic and metalinguistic tasks were similar to those observed in the dominant hemisphere of controls, suggesting that his language network conforms to a left-like linguistic neural blueprint. However, a stronger frontal recruitment suggests that linguistic tasks are more demanding for him. Finally, no specific reading activation was found in EB's occipitotemporal region, a finding consistent with the surface dyslexia-like behavioral pattern of the patient. While a lone right hemisphere may not be sufficient to guarantee full blown linguistic competences after early hemispherectomy, EB's behavioral and fMRI patterns suggest that his lone right hemisphere followed a left-like blueprint of the linguistic network.

  4. Why the Left Hemisphere Is Dominant for Speech Production: Connecting the Dots

    Directory of Open Access Journals (Sweden)

    Harvey Martin Sussman

    2015-12-01

    Full Text Available Evidence from seemingly disparate areas of speech/language research is reviewed to form a unified theoretical account for why the left hemisphere is specialized for speech production. Research findings from studies investigating hemispheric lateralization of infant babbling, the primacy of the syllable in phonological structure, rhyming performance in split-brain patients, rhyming ability and phonetic categorization in children diagnosed with developmental apraxia of speech, rules governing exchange errors in spoonerisms, organizational principles of neocortical control of learned motor behaviors, and multi-electrode recordings of human neuronal responses to speech sounds are described and common threads highlighted. It is suggested that the emergence, in developmental neurogenesis, of a hard-wired, syllabically-organized, neural substrate representing the phonemic sound elements of one’s language, particularly the vocalic nucleus, is the crucial factor underlying the left hemisphere’s dominance for speech production.

  5. Estradiol levels during the menstrual cycle differentially affect latencies to right and left hemispheres during dichotic listening: an ERP study.

    Science.gov (United States)

    Tillman, Gail D

    2010-02-01

    Many behavioral studies have found high-estrogen phases of the menstrual cycle to be associated with enhanced left-hemisphere processing and low-estrogen phases to be associated with better right-hemisphere processing. This study examined the changing of hemispheric asymmetry during the menstrual cycle by analyzing event-related potential (ERP) data from midline and both hemispheres of 23 women during their performance of a dichotic tasks shown to elicit a left-hemisphere response (semantic categorization) and a right-hemisphere response (complex tones). Each woman was tested during her high-estrogen follicular phase and low-estrogen menstrual phase. Salivary assays of estradiol and progesterone were used to confirm cycle phase. Analyses of the ERP data revealed that latency for each hemisphere was differentially affected by phase and target side, such that latencies to the left hemisphere and from the right ear were shorter during the high-estrogen phase, and latencies to the right hemisphere and from the left ear were shorter during the low-estrogen phase. These findings supply electrophysiological correlates of the cyclically based interhemispheric differences evinced by behavioral studies. 2009 Elsevier Ltd. All rights reserved.

  6. Hemispheric prevalence during chewing in normal right-handed and left-handed subjects: a functional magnetic resonance imaging preliminary study.

    Science.gov (United States)

    Bracco, Pietro; Anastasi, Giuseppe; Piancino, Maria Grazia; Frongia, Gianluigi; Milardi, Demetrio; Favaloro, Angelo; Bramanti, Placido

    2010-04-01

    This study evaluated the activation of different cortical areas during nondeliberate chewing of soft and hard boluses in five right-handed and five left-handed subjects with normal occlusion, to determine different hemispheric prevalences. The study was conducted with a functional Magnetic Resonance Imaging (1.5 T Magnetom Vision - Siemens Medical, Germany) using a head coil. The results showed that the most frequently activated areas were Brodmann's areas four and six in the primary motor and premotor cortex, the insula and Broca's area and, overall, showed greater activity of the cortical mastication area (CMA) in the right hemisphere for right-handed and in the left hemisphere for left-handed subjects.

  7. Hemispheric specificity for proprioception: Postural control of standing following right or left hemisphere damage during ankle tendon vibration.

    Science.gov (United States)

    Duclos, Noémie C; Maynard, Luc; Abbas, Djawad; Mesure, Serge

    2015-11-02

    Right brain damage (RBD) following stroke often causes significant postural instability. In standing (without vision), patients with RBD are more unstable than those with left brain damage (LBD). We hypothesised that this postural instability would relate to the cortical integration of proprioceptive afferents. The aim of this study was to use tendon vibration to investigate whether these changes were specific to the paretic or non-paretic limbs. 14 LBD, 12 RBD patients and 20 healthy subjects were included. Displacement of the Centre of Pressure (CoP) was recorded during quiet standing, then during 3 vibration conditions (80 Hz - 20s): paretic limb, non-paretic limb (left and right limbs for control subjects) and bilateral. Vibration was applied separately to the peroneal and Achilles tendons. Mean antero-posterior position of the CoP, variability and velocity were calculated before (4s), during and after (24s) vibration. For all parameters, the strongest perturbation was during Achilles vibrations. The Achilles non-paretic condition induced a larger backward displacement than the Achilles paretic condition. This condition caused specific behaviour on the velocity: the LBD group was perturbed at the onset of the vibrations, but gradually recovered their stability; the RBD group was significantly perturbed thereafter. After bilateral Achilles vibration, RBD patients required the most time to restore initial posture. The reduction in use of information from the paretic limb may be a central strategy to deal with risk-of-fall situations such as during Achilles vibration. The postural behaviour is profoundly altered by lesions of the right hemisphere when proprioception is perturbed. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Disturbances of mental image processing in post-stroke patients with left and right hemisphere damage.

    Science.gov (United States)

    Pachalska, M; Talar, J; Brodziak, A; MacQueen, B D

    2001-01-01

    The purpose of this article is to point out significant differences in how mental images are processed by post-stroke patients with left and right hemisphere damage. The issues involved are of theoretical importance because of the light shed on the modularity of cerebral functions, especially the imagination, and of clinical importance due to the better understanding of the underlying pathomechanism. The research involved 82 right-handed patients with a lesion in the left hemisphere (Group L), 82 right-handed patients with a lesion in the right hemisphere (Group R), and, as a control group, 82 patients with musculo-skeletal disorders not affecting the central nervous system (Group C), matched by age and sex. Image processing of complex notions was examined by using selected items from the Simple Neurolinguistic Test. In the control group, the majority of the patients responded to most of the prompts with polymodal associations of various types. In Group L, responses were dominated by isolated elements of the complex situation, while in Group R the associations were mostly verbal (lexical) and highly restricted in scope. The results indicate that the loss of LH functions interferes with the ability to assemble pieces of polymodal image information into sensible strings, while the loss of RH functions leaves strings to which little information is attached.

  9. The development of pragmatic skills in children after hemispherotomy: Contribution from left and right hemispheres.

    Science.gov (United States)

    Save-Pédebos, Jessica; Pinabiaux, Charlotte; Dorfmuller, Georg; Sorbets, Sarah Ferrand; Delalande, Olivier; Jambaqué, Isabelle; Bulteau, Christine

    2016-02-01

    Hemispherotomy (H) is the standard treatment used to cure hemispheric epileptic syndromes in childhood. The postoperative linguistic profile involves hemispheric specialization processes and developmental cognitive plasticity. This research concerns pragmatic aspects of language as a tool for communication which involves both linguistic and extralinguistic communication in context. Our aim was to analyze whether any correlation exists with age at surgery and side of surgery on pragmatic skills following H. Forty children who underwent H (23 females, 16 right H) were evaluated at a mean age of 12.8 years (±2.6) with two receptive tasks (oral comprehension and syntactic judgment), the Children's Communication Checklist (CCC) rating scale, and the Behavioral Rating Inventory of Executive Function (BRIEF) questionnaire in order to evaluate the role of executive functions on pragmatic skills. Children operated on before the age of 18 months were considered the "early" group (5 right H and 9 left H), while those operated on later were called the "late" group (11 right H and 15 left H). The whole group had significant deficits in all three measures. We demonstrated a statistically significant crossed interaction between the side of H and the age at H with pragmatic language impairments (F(1,36)=17.48; p=.0002) and disorders in executive function (F(1,36)=5.80; p=.021) in left early H and in right late H patients. These findings are consistent with the previous studies of pragmatic language impairments concerning adolescents and adults with right hemisphere damage and emphasize the contribution of structural language in the early stage of verbal communication. These results emphasize for the first time that hemispherotomized children have pragmatic language impairments that are independent of receptive language. Our findings are congruent with the recent theory on pragmatic language development in childhood with evidence of a participation of the left hemisphere at the

  10. Mapping nouns and finite verbs in left hemisphere tumors: a direct electrical stimulation study.

    Science.gov (United States)

    Rofes, Adrià; Spena, Giannantonio; Talacchi, Andrea; Santini, Barbara; Miozzo, Antonio; Miceli, Gabriele

    2017-04-01

    Neurosurgical mapping studies with nouns and finite verbs are scarce and subcortical data are nonexistent. We used a new task that uses finite verbs in six Italian-speaking patients with gliomas in the left language-dominant hemisphere. Language-relevant positive areas were detected only with nouns in four patients, with both tasks yet in distinct cortical areas in one patient, and only with finite verbs in another patient. Positive areas and types of errors varied across participants. Finite verbs provide complementary information to nouns, and permit more accurate mapping of language production when nouns are unaffected by electrical stimulation.

  11. Early left-hemispheric dysfunction of face processing in congenital prosopagnosia: an MEG study.

    Directory of Open Access Journals (Sweden)

    Christian Dobel

    Full Text Available BACKGROUND: Congenital prosopagnosia is a severe face perception impairment which is not acquired by a brain lesion and is presumably present from birth. It manifests mostly by an inability to recognise familiar persons. Electrophysiological research has demonstrated the relevance to face processing of a negative deflection peaking around 170 ms, labelled accordingly as N170 in the electroencephalogram (EEG and M170 in magnetoencephalography (MEG. The M170 was shown to be sensitive to the inversion of faces and to familiarity--two factors that are assumed to be crucial for congenital prosopagnosia. In order to locate the cognitive dysfunction and its neural correlates, we investigated the time course of neural activity in response to these manipulations. METHODOLOGY: Seven individuals with congenital prosopagnosia and seven matched controls participated in the experiment. To explore brain activity with high accuracy in time, we recorded evoked magnetic fields (275 channel whole head MEG while participants were looking at faces differing in familiarity (famous vs. unknown and orientation (upright vs. inverted. The underlying neural sources were estimated by means of the least square minimum-norm-estimation (L2-MNE approach. PRINCIPAL FINDINGS: The behavioural data corroborate earlier findings on impaired configural processing in congenital prosopagnosia. For the M170, the overall results replicated earlier findings, with larger occipito-temporal brain responses to inverted than upright faces, and more right- than left-hemispheric activity. Compared to controls, participants with congenital prosopagnosia displayed a general decrease in brain activity, primarily over left occipitotemporal areas. This attenuation did not interact with familiarity or orientation. CONCLUSIONS: The study substantiates the finding of an early involvement of the left hemisphere in symptoms of prosopagnosia. This might be related to an efficient and overused featural

  12. The course of apraxia and ADL functioning in left hemisphere stroke patients treated in rehabilitation centres and nursing homes.

    Science.gov (United States)

    Donkervoort, Mireille; Dekker, Joost; Deelman, Betto

    2006-12-01

    To study the course of apraxia and daily life functioning (ADL) in left hemisphere stroke patients with apraxia. Prospective cohort study. Rehabilitation centres and nursing homes. One hundred and eight left hemisphere stroke patients with apraxia, hospitalized in rehabilitation centres and nursing homes. ADL-observations, Barthel ADL Index, Apraxia Test, Motricity Index. During the study period of 20 weeks, patients showed small improvements in apraxia (standardized mean differences of 0.19 and 0.33) and medium-sized improvements in ADL functioning (standardized mean differences from 0.37 to 0.61). About 88% of the patients were still apraxic at week 20. Less improvement in apraxia was observed in initially less severe apraxic patients. Less improvement in ADL functioning was found to be associated with more severe apraxia, a more independent initial ADL score, higher age, impaired motor functioning and longer time between stroke and first assessment. Apraxia in stroke patients is a persistent disorder, which has an adverse influence on ADL recovery.

  13. Use of prosodic cues in the production of idiomatic and literal sentences by individuals with right- and left-hemisphere damage.

    Science.gov (United States)

    Bélanger, Nathalie; Baum, Shari R; Titone, Debra

    2009-07-01

    The neural bases of prosody during the production of literal and idiomatic interpretations of literally plausible idioms was investigated. Left- and right-hemisphere-damaged participants and normal controls produced literal and idiomatic versions of idioms (He hit the books.) All groups modulated duration to distinguish the interpretations. LHD patients, however, showed typical speech timing difficulties. RHD patients did not differ from the normal controls. The results partially support a differential lateralization of prosodic cues in the two cerebral hemispheres [Van Lancker, D., & Sidtis, J. J. (1992). The identification of affective-prosodic stimuli by left- and right-hemisphere-damaged subjects: All errors are not created equal. Journal of Speech and Hearing Research, 35, 963-970]. Furthermore, extended final word lengthening appears to mark idiomaticity.

  14. Greater left cerebral hemispheric metabolism in bulimia assessed by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.C.; Hagman, J.; Buchsbaum, M.S.; Blinder, B.; Derrfler, M.; Tai, W.Y.; Hazlett, E.; Sicotte, N. (Univ. of California, Irvine (USA))

    1990-03-01

    Eight women with bulimia and eight age- and sex-matched normal control subjects were studied with positron emission tomography using (18F)-fluorodeoxyglucose (FDG) as a tracer of brain metabolic rate. Subjects performed a visual vigilance task during FDG uptake. In control subjects, the metabolic rate was higher in the right hemisphere than in the left, but patients with bulimia did not have this normal asymmetry. Lower metabolic rates in the basal ganglia, found in studies of depressed subjects, and higher rates in the basal ganglia, reported in a study of anorexia nervosa, were not found. This is consistent with the suggestion that bulimia is a diagnostic grouping distinct from these disorders.

  15. Cognitive outcome after awake surgery for left and right hemisphere tumours

    Directory of Open Access Journals (Sweden)

    Elke De Witte

    2015-04-01

    Full Text Available INTRODUCTION: Awake surgery in eloquent brain regions is performed to preserve language and other cognitive functions. Although in general, no major permanent cognitive deficits are found after awake brain surgery, clinically relevant impairments are detected and cognitive recovery takes longer than generally assumed (3 months (Santini et al., 2012; Satoer et al., 2014; Talacchi et al., 2012. However, as there is a lack of extensive cognitive follow-up data it is unknown when recovery takes place. In addition, the influence of critical language sites identified by direct electrical stimulation (DES and tumour variables (e.g. left/right tumour location, tumour grade on long-term cognitive findings remains unclear. METHODS: In this longitudinal study the short-term and long-term effects of awake surgery on cognition were investigated in 40 patients (29 patients with left and 11 with right hemisphere tumours. Language, memory, attentional, executive and visuospatial functions were assessed in the preoperative phase, at short-term follow-up (6 weeks postsurgery and at long-term follow-up (6 months postsurgery with a neuropsychological protocol. In addition, the effect of intraoperative critical language sites, left/right tumour location, hemispheric language dominance, extent of resection and adjuvant treatment on cognitive change was studied. RESULTS: Both pre- and postoperatively, the mean performance of the patients was worse (impairment = z-score below -2 than the performance of the normal population in the language domain, the memory domain, the attentional and executive domain (p .05. Awake surgery negatively affected language, attentional and executive functions but not memory and visuospatial functions. At 6 weeks postsurgery, performance on all language, attentional and executive tasks deteriorated (object/action naming, semantic/phonological fluency from DuLIP, Token test; Trail Making Test A & B, Stroop I, II, & III. At 6 months

  16. Activity levels in the left hemisphere caudate-fusiform circuit predict how well a second language will be learned.

    Science.gov (United States)

    Tan, Li Hai; Chen, Lin; Yip, Virginia; Chan, Alice H D; Yang, Jing; Gao, Jia-Hong; Siok, Wai Ting

    2011-02-08

    How second language (L2) learning is achieved in the human brain remains one of the fundamental questions of neuroscience and linguistics. Previous neuroimaging studies with bilinguals have consistently shown overlapping cortical organization of the native language (L1) and L2, leading to a prediction that a common neurobiological marker may be responsible for the development of the two languages. Here, by using functional MRI, we show that later skills to read in L2 are predicted by the activity level of the fusiform-caudate circuit in the left hemisphere, which nonetheless is not predictive of the ability to read in the native language. We scanned 10-y-old children while they performed a lexical decision task on L2 (and L1) stimuli. The subjects' written language (reading) skills were behaviorally assessed twice, the first time just before we performed the fMRI scan (time 1 reading) and the second time 1 y later (time 2 reading). A whole-brain based analysis revealed that activity levels in left caudate and left fusiform gyrus correlated with L2 literacy skills at time 1. After controlling for the effects of time 1 reading and nonverbal IQ, or the effect of in-scanner lexical performance, the development in L2 literacy skills (time 2 reading) was also predicted by activity in left caudate and fusiform regions that are thought to mediate language control functions and resolve competition arising from L1 during L2 learning. Our findings suggest that the activity level of left caudate and fusiform regions serves as an important neurobiological marker for predicting accomplishment in reading skills in a new language.

  17. Dissociations of action means and outcome processing in left-hemisphere stroke.

    Science.gov (United States)

    Kalénine, Solène; Shapiro, Allison D; Buxbaum, Laurel J

    2013-06-01

    Previous evidence suggests that distinct fronto-parietal regions may be involved in representing action kinematics (means) and action results (outcome) during action observation. However, the evidence is contradictory with respect to the precise regions that are critical for each type of representation. Additionally unknown is the degree to which ability to detect action means and outcome during observation is related to action production performance. We used a behavioral task to evaluate the ability of healthy and left-hemisphere stroke participants to detect differences between pairs of videos that dissociated object-related action means (e.g., wiping with circular or straight movement) and/or outcome (e.g., applying or removing detergent). We expected that deficits in detecting action means would be associated with spatiomotor gesture production deficits, whereas deficits in detecting action outcome would predict impairments in complex naturalistic action. We also hypothesized a posterior to anterior gradient in the regions critical for each type of representation, disproportionately affecting means and outcome encoding, respectively. Results indicated that outcome--but not means--detection predicted naturalistic action performance in stroke participants. Regression and voxel lesion-symptom mapping analyses of lesion data revealed that means--but not outcome--coding relies on the integrity of the left inferior parietal lobe, whereas no selective critical brain region could be identified for outcome detection. Thus, means and outcome representations are dissociable at both the behavioral and neuroanatomical levels. Furthermore, the data are consistent with a degree of parallelism between action perception and production tasks. Finally, they reinforce the evidence for a critical role of the left inferior parietal lobule in the representation of action means, whereas action outcome may rely on a more distributed neural circuit. Copyright © 2013 Elsevier Ltd. All

  18. Right: Left:: East: West. Evidence that individuals from East Asian and South Asian cultures emphasize right hemisphere functions in comparison to Euro-American cultures.

    Science.gov (United States)

    Rozin, Paul; Moscovitch, Morris; Imada, Sumio

    2016-09-01

    We present evidence that individuals from East or South Asian cultures (Japanese college students in Japan and East or South Asian born and raised college students in the USA) tend to exhibit default thinking that corresponds to right hemisphere holistic functions, as compared to Caucasian individuals from a Western culture (born and raised in the USA). In two lateralized tasks (locating the nose in a scrambled face, and global-local letter task), both Asian groups showed a greater right hemisphere bias than the Western group. In a third lateralized task, judging similarity in terms of visual form versus functional/semantic categorizations, there was not a reliable difference between the groups. On a classic, ambiguous face composed of vegetables, both Eastern groups displayed a greater right hemisphere (holistic face processing) bias than the Western group. These results support an "East - Right Hemisphere, West - Left Hemisphere" hypothesis, as originally proposed by Ornstein (1972). This hypothesis is open as to the degree to which social-cultural forces were involved in hemispheric specialization, or the opposite, or both. Our aim is to encourage a more thorough analysis of this hypothesis, suggesting both lateralization studies corresponding to documented East-West differences, and East-West studies corresponding to lateralization differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Post-stroke acquired amusia: A comparison between right- and left-brain hemispheric damages.

    Science.gov (United States)

    Jafari, Zahra; Esmaili, Mahdiye; Delbari, Ahmad; Mehrpour, Masoud; Mohajerani, Majid H

    2017-01-01

    Although extensive research has been published about the emotional consequences of stroke, most studies have focused on emotional words, speech prosody, voices, or facial expressions. The emotional processing of musical excerpts following stroke has been relatively unexplored. The present study was conducted to investigate the effects of chronic stroke on the recognition of basic emotions in music. Seventy persons, including 25 normal controls (NC), 25 persons with right brain damage (RBD) from stroke, and 20 persons with left brain damage (LBD) from stroke between the ages of 31-71 years were studied. The Musical Emotional Bursts (MEB) test, which consists of a set of short musical pieces expressing basic emotional states (happiness, sadness, and fear) and neutrality, was used to test musical emotional perception. Both stroke groups were significantly poorer than normal controls for the MEB total score and its subtests (p amusia with greater severity in RBD than LBD. These results supported the "valence hypothesis" of right hemisphere dominance in processing negative emotions.

  20. Dissociation between Semantic Representations for Motion and Action Verbs: Evidence from Patients with Left Hemisphere Lesions.

    Science.gov (United States)

    Taylor, Lawrence J; Evans, Carys; Greer, Joanna; Senior, Carl; Coventry, Kenny R; Ietswaart, Magdalena

    2017-01-01

    This multiple single case study contrasted left hemisphere stroke patients ( N = 6) to healthy age-matched control participants ( N = 15) on their understanding of action (e.g., holding, clenching) and motion verbs (e.g., crumbling, flowing). The tasks required participants to correctly identify the matching verb or associated picture. Dissociations on action and motion verb content depending on lesion site were expected. As predicted for verbs containing an action and/or motion content, modified t -tests confirmed selective deficits in processing motion verbs in patients with lesions involving posterior parietal and lateral occipitotemporal cortex. In contrast, deficits in verbs describing motionless actions were found in patients with more anterior lesions sparing posterior parietal and lateral occipitotemporal cortex. These findings support the hypotheses that semantic representations for action and motion are behaviorally and neuro-anatomically dissociable. The findings clarify the differential and critical role of perceptual and motor regions in processing modality-specific semantic knowledge as opposed to a supportive but not necessary role. We contextualize these results within theories from both cognitive psychology and cognitive neuroscience that make claims over the role of sensory and motor information in semantic representation.

  1. Asymmetry of temporal auditory T-complex: right ear-left hemisphere advantage in Tb timing in children.

    Science.gov (United States)

    Bruneau, Nicole; Bidet-Caulet, Aurélie; Roux, Sylvie; Bonnet-Brilhault, Frédérique; Gomot, Marie

    2015-02-01

    To investigate brain asymmetry of the temporal auditory evoked potentials (T-complex) in response to monaural stimulation in children compared to adults. Ten children (7 to 9 years) and ten young adults participated in the study. All were right-handed. The auditory stimuli used were tones (1100 Hz, 70 dB SPL, 50 ms duration) delivered monaurally (right, left ear) at four different levels of stimulus onset asynchrony (700-1100-1500-3000 ms). Latency and amplitude of responses were measured at left and right temporal sites according to the ear stimulated. Peaks of the three successive deflections (Na-Ta-Tb) of the T-complex were greater in amplitude and better defined in children than in adults. Amplitude measurements in children indicated that Na culminates on the left hemisphere whatever the ear stimulated whereas Ta and Tb culminate on the right hemisphere but for left ear stimuli only. Peak latency displayed different patterns of asymmetry. Na and Ta displayed shorter latencies for contralateral stimulation. The original finding was that Tb peak latency was the shortest at the left temporal site for right ear stimulation in children. Amplitude increased and/or peak latency decreased with increasing SOA, however no interaction effect was found with recording site or with ear stimulated. Our main original result indicates a right ear-left hemisphere timing advantage for Tb peak in children. The Tb peak would therefore be a good candidate as an electrophysiological marker of ear advantage effects during dichotic stimulation and of functional inter-hemisphere interactions and connectivity in children. Copyright © 2014. Published by Elsevier B.V.

  2. A case of expressive-vocal amusia in a right-handed patient with left hemispheric cerebral infarction.

    Science.gov (United States)

    Uetsuki, Shizuka; Kinoshita, Hiroshi; Takahashi, Ryuichi; Obata, Satoshi; Kakigi, Tatsuya; Wada, Yoshiko; Yokoyama, Kazumasa

    2016-03-01

    A 53-year-old right-handed woman had an extensive lesion in the left hemisphere due to an infarction caused by vasospasm secondary to subarachnoid bleeding. She exhibited persistent expressive-vocal amusia with no symptoms of aphasia. Evaluation of the patient's musical competence using the Montreal Battery for Evaluation of Amusia, rhythm reproduction tests, acoustic analysis of pitch upon singing familiar music, Japanese standard language tests, and other detailed clinical examinations revealed that her amusia was more dominantly related to pitch production. The intactness of her speech provided strong evidence that the right hemisphere played a major role in her linguistic processing. Data from functional magnetic resonance imaging while she was singing a familiar song, a scale, and reciting lyrics indicated that perilesional residual activation in the left hemisphere was associated with poor pitch production, while right hemispheric activation was involved in linguistic processing. The localization of infarction more anterior to the left Sylvian fissure might be related to the dominant deficits in expressive aspects of the singing of the patient. Compromised motor programming producing a single tone may have made a major contribution to her poor singing. Imperfect auditory feedback due to borderline perceptual ability or improper audio-motor associations might also have played a role. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. A tale of two hemispheres: Contrasting socioemotional dysfunction in right- versus left-lateralised semantic dementia

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    Muireann Irish

    Full Text Available ABSTRACT Objective: Semantic dementia, a subtype of frontotemporal lobar degeneration, is characterised by cross-modal loss of conceptual knowledge attributable to progressive degeneration of the left anterior temporal lobe. Much less is known regarding the clinical presentation of SD patients with predominantly right-lateralised atrophy. Recent reports emphasise marked socioemotional and behavioural disturbances in such cases. Given the importance of the right anterior temporal lobes in social cognition, we hypothesised that socioemotional functioning would be disproportionately affected in right versus left-lateralised SD cases. Methods: We assessed well-characterised cases of predominantly right (n=10 and left (n=12 SD and 20 matched healthy controls on tests of emotion processing and interpersonal functioning. Results: Right SD cases showed disproportionate difficulties in the recognition of positive and negative facial emotions, specifically happiness and anger, compared with left SD cases. Deficits in anger recognition persisted in right SD despite covarying for facial and semantic processing. On a contextually rich task of emotion recognition using multimodal videos, no subgroup differences were evident. Finally, empathic concern was rated as significantly lower by caregivers of right versus left SD cases. Overall, the extent of socioemotional disturbance was associated with the degree of behavioural changes in SD. Conclusion: Our results reveal considerable overlap in the extent to which socioemotional processes are disrupted in left and right-lateralised cases of SD. Notably, however, right SD cases show disproportionate deficits for recognition of facial emotions and the capacity for empathic concern, supporting a specialised role for the right anterior temporal lobes in mediating these cognitive functions.

  4. Music, Hemisphere Preference and Imagery.

    Science.gov (United States)

    Stratton, Valerie N.; Zalanowski, Annette H.

    Two experiments were conducted to determine a possible relationship between the right hemisphere, music perception, and mental imagery. The first experiment compared two groups of college students, one of which showed a preference for left hemisphere thinking (n=22) and the other a preference for right hemisphere thinking (n=20), in order to test…

  5. Cortical activity in the left and right hemispheres during language-related brain functions

    DEFF Research Database (Denmark)

    Lassen, N A; Larsen, B

    1980-01-01

    of cortical activity seen during various language functions, emphasizing the practically symmetrical involvement in both hemispheres. A case of auditive agnosia (with complete cortical word deafness but preserved pure tone thresholds) is presented. The patient's normal speech constitutes evidence...

  6. Augmenting Melodic Intonation Therapy with non-invasive brain stimulation to treat impaired left-hemisphere function: two case studies

    Directory of Open Access Journals (Sweden)

    Shahd eAl-Janabi

    2014-02-01

    Full Text Available The purpose of this study was to investigate whether or not the right hemisphere can be engaged using Melodic Intonation Therapy (MIT and excitatory repetitive transcranial magnetic stimulation (rTMS to improve language function in people with aphasia. The two participants in this study (GOE and AMC have chronic non-fluent aphasia. A functional Magnetic Resonance Imaging (fMRI task was used to localize the right Broca’s homologue area in the inferior frontal gyrus for rTMS coil placement. The treatment protocol included an rTMS phase, which consisted of 3 treatment sessions that used an excitatory stimulation method known as intermittent theta burst stimulation, and a sham-rTMS phase, which consisted of 3 treatment sessions that used a sham coil. Each treatment session was followed by 40 minutes of MIT. A linguistic battery was administered after each session. Our findings show that one participant, GOE, improved in verbal fluency and the repetition of phrases treated with MIT in combination with TMS. However, AMC showed no evidence of behavioural benefit from this brief treatment trial. Post-treatment neural activity changes were observed for both participants in the left Broca’s area and right Broca’s homologue. These case studies indicate that a combination of rTMS applied to the right Broca’s homologue and MIT has the potential to improve speech and language outcomes for at least some people with post-stroke aphasia.

  7. Augmenting melodic intonation therapy with non-invasive brain stimulation to treat impaired left-hemisphere function: two case studies.

    Science.gov (United States)

    Al-Janabi, Shahd; Nickels, Lyndsey A; Sowman, Paul F; Burianová, Hana; Merrett, Dawn L; Thompson, William F

    2014-01-01

    The purpose of this study was to investigate whether or not the right hemisphere can be engaged using Melodic Intonation Therapy (MIT) and excitatory repetitive transcranial magnetic stimulation (rTMS) to improve language function in people with aphasia. The two participants in this study (GOE and AMC) have chronic non-fluent aphasia. A functional Magnetic Resonance Imaging (fMRI) task was used to localize the right Broca's homolog area in the inferior frontal gyrus for rTMS coil placement. The treatment protocol included an rTMS phase, which consisted of 3 treatment sessions that used an excitatory stimulation method known as intermittent theta burst stimulation, and a sham-rTMS phase, which consisted of 3 treatment sessions that used a sham coil. Each treatment session was followed by 40 min of MIT. A linguistic battery was administered after each session. Our findings show that one participant, GOE, improved in verbal fluency and the repetition of phrases when treated with MIT in combination with TMS. However, AMC showed no evidence of behavioral benefit from this brief treatment trial. Post-treatment neural activity changes were observed for both participants in the left Broca's area and right Broca's homolog. These case studies indicate that a combination of MIT and rTMS applied to the right Broca's homolog has the potential to improve speech and language outcomes for at least some people with post-stroke aphasia.

  8. Electroencephalographic (eeg coherence between visual and motor areas of the left and the right brain hemisphere while performing visuomotor task with the right and the left hand

    Directory of Open Access Journals (Sweden)

    Simon Brežan

    2007-09-01

    Full Text Available Background: Unilateral limb movements are based on the activation of contralateral primary motor cortex and the bilateral activation of premotor cortices. Performance of a visuomotor task requires a visuomotor integration between motor and visual cortical areas. The functional integration (»binding« of different brain areas, is probably mediated by the synchronous neuronal oscillatory activity, which can be determined by electroencephalographic (EEG coherence analysis. We introduced a new method of coherence analysis and compared coherence and power spectra in the left and right hemisphere for the right vs. left hand visuomotor task, hypothesizing that the increase in coherence and decrease in power spectra while performing the task would be greater in the contralateral hemisphere.Methods: We analyzed 6 healthy subjects and recorded their electroencephalogram during visuomotor task with the right or the left hand. For data analysis, a special Matlab computer programme was designed. The results were statistically analysed by a two-way analysis of variance, one-way analysis of variance and post-hoc t-tests with Bonferroni correction.Results: We demonstrated a significant increase in coherence (p < 0.05 for the visuomotor task compared to control tasks in alpha (8–13 Hz in beta 1 (13–20 Hz frequency bands between visual and motor electrodes. There were no significant differences in coherence nor power spectra depending on the hand used. The changes of coherence and power spectra between both hemispheres were symmetrical.Conclusions: In previous studies, a specific increase of coherence and decrease of power spectra for the visuomotor task was found, but we found no conclusive asymmetries when performing the task with right vs. left hand. This could be explained in a way that increases in coherence and decreases of power spectra reflect symmetrical activation and cooperation between more complex visual and motor brain areas.

  9. Left inferior frontal gyrus mediates morphosyntax: ERP evidence from verb processing in left-hemisphere damaged patients.

    Science.gov (United States)

    Regel, Stefanie; Kotz, Sonja A; Henseler, Ilona; Friederici, Angela D

    2017-01-01

    Neurocognitive models of language comprehension have proposed different mechanisms with different neural substrates mediating human language processing. Whether the left inferior frontal gyrus (LIFG) is engaged in morpho-syntactic information processing is currently still controversially debated. The present study addresses this issue by examining the processing of irregular verb inflection in real words (e.g., swim > swum > swam) and pseudowords (e.g., frim > frum > fram) by using event-related brain potentials (ERPs) in neurological patients with lesions in the LIFG involving Broca's area as well as healthy controls. Different ERP patterns in response to the grammatical violations were observed in both groups. Controls showed a biphasic negativity-P600 pattern in response to incorrect verb inflections whereas patients with LIFG lesions displayed a N400. For incorrect pseudoword inflections, a late positivity was found in controls, while no ERP effects were obtained in patients. These findings of different ERP patterns in the two groups strongly indicate an involvement of LIFG in morphosyntactic processing, thereby suggesting brain regions' specialization for different language functions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Embedded Words in Visual Word Recognition: Does the Left Hemisphere See the Rain in Brain?

    Science.gov (United States)

    McCormick, Samantha F.; Davis, Colin J.; Brysbaert, Marc

    2010-01-01

    To examine whether interhemispheric transfer during foveal word recognition entails a discontinuity between the information presented to the left and right of fixation, we presented target words in such a way that participants fixated immediately left or right of an embedded word (as in "gr*apple", "bull*et") or in the middle…

  11. When right is all that's left: plasticity of right-hemisphere tracts in a young aphasic patient

    Science.gov (United States)

    Zipse, Lauryn; Norton, Andrea; Marchina, Sarah; Schlaug, Gottfried

    2012-01-01

    Using an adapted version of melodic intonation therapy (MIT), we treated an adolescent girl with a very large left-hemisphere lesion and severe nonfluent aphasia secondary to an ischemic stroke. At the time of her initial assessment 1.25 years after her stroke, she had reached a plateau in her recovery despite intense and long-term traditional speech-language therapy (approximately five times per week for more than one year). Following an intensive course of treatment with our adapted form of MIT, her performance improved on both trained and untrained phrases, as well as on speech and language tasks. These behavioral improvements were accompanied by functional MRI changes in the right frontal lobe as well as by an increased volume of white matter pathways in the right hemisphere. No increase in white matter volume was seen in her healthy twin sister, who was scanned twice over the same time period. This case study not only provides further evidence for MIT's effectiveness, but also indicates that intensive treatment can induce functional and structural changes in a right hemisphere fronto-temporal network. PMID:22524365

  12. When right is all that is left: plasticity of right-hemisphere tracts in a young aphasic patient.

    Science.gov (United States)

    Zipse, Lauryn; Norton, Andrea; Marchina, Sarah; Schlaug, Gottfried

    2012-04-01

    Using an adapted version of Melodic Intonation Therapy (MIT), we treated an adolescent girl with a very large left-hemisphere lesion and severe nonfluent aphasia secondary to an ischemic stroke. At the time of her initial assessment 15 months after her stroke, she had reached a plateau in her recovery despite intense and long-term traditional speech-language therapy (approximately five times per week for more than one year). Following an intensive course of treatment with our adapted form of MIT, her performance improved on both trained and untrained phrases, as well as on speech and language tasks. These behavioral improvements were accompanied by functional MRI changes in the right frontal lobe as well as by an increased volume of white matter pathways in the right hemisphere. No increase in white matter volume was seen in her healthy twin sister, who was scanned twice over the same time period. This case study not only provides further evidence for MIT's effectiveness, but also indicates that intensive treatment can induce functional and structural changes in a right-hemisphere fronto-temporal network. © 2012 New York Academy of Sciences.

  13. Electrophysiological evidence for the action of a center-surround mechanism on semantic processing in the left hemisphere

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    Diana eDeacon

    2013-12-01

    Full Text Available Physiological evidence was sought for a center-surround attentional mechanism (CSM, which has been proposed to assist in the retrieval of weakly activated items from semantic memory. The CSM operates by facilitating strongly related items in the center of the weakly activated area of semantic memory, and inhibiting less strongly related items in its surround. In this study weak activation was created by having subjects acquire the meanings of new words to a recall criterion of only 50%. Subjects who attained this approximate criterion level of performance were subsequently included in a semantic priming task, during which ERPs were recorded. Primes were newly learned rare words, and targets were either synonyms, nonsynonymously related words, or unrelated words. All stimuli were presented to the RVF/LH (right visual field/left hemisphere or the LVF/RH (left visual field/right hemisphere. Under RVF/LH stimulation the newly learned word primes produced facilitation on N400 for synonym targets, and inhibition for related targets. No differences were observed under LVF/RH stimulation. The LH thus, supports a CSM, whereby a synonym in the center of attention focused on the newly learned word is facilitated, whereas a related word in the surround is inhibited. The data are consistent with the view of this laboratory that semantic memory is subserved by a spreading activation system in the LH. Also consistent with our view, there was no evidence of spreading activation in the RH. The findings are discussed in the context of additional recent theories of semantic memory. Finally, the adult right hemisphere may require more learning than the LH in order to demonstrate evidence of meaning acquisition.

  14. Improved Spatial Ability Correlated with Left Hemisphere Dysfunction in Turner's Syndrome. Implications for Mechanism.

    Science.gov (United States)

    Rovet, Joanne F.

    This study contrasts the performance of a 17-year-old female subject with Turner's syndrome before and after developing left temporal lobe seizures, as a means of identifying the mechanism responsible for the Turner's syndrome spatial impairment. The results revealed a deficit in spatial processing before onset of the seizure disorder. Results…

  15. Lateralization of brain activation to imagination and smell of odors using functional magnetic resonance imaging (fMRI): left hemispheric localization of pleasant and right hemispheric localization of unpleasant odors.

    Science.gov (United States)

    Henkin, R I; Levy, L M

    2001-01-01

    Our goal was to use functional MRI (fMRI) of brain to reveal activation in each cerebral hemisphere in response to imagination and smell of odors. FMRI brain scans were obtained in 24 normal subjects using multislice fast low angle shot (FLASH) MRI in response to imagination of banana and peppermint odors and in response to smell of corresponding odors of amyl acetate and menthone, respectively, and of pyridine. Three coronal sections selected from anterior to posterior brain regions were used. Similar studies were obtained in two patients with hyposmia using FLASH MRI and in one patient with hyposmia using echo planar imaging (EPI) both before and after theophylline treatment that returned smell function to or toward normal in each patient and in two patients with birhinal phantosmia (persistent foul odor) and global phantogeusia (persistent foul taste) with FLASH and EPI fMRI before and after treatment with neuroleptic drugs that inhibited their phantosmia and phantogeusia. Activation images were derived using correlation analysis. Ratios of hemispheric areas of brain activation to total hemispheric brain areas were calculated for FLASH fMRI, and numerical counts of pixel clusters in each hemisphere were made for EPI studies. Total pixel cluster counts in localized regions of each hemispheric section were also obtained. In normal subjects, activation generally occurred in left (L) > right (R) brain hemisphere in response to banana and peppermint odor imagination and to smell of corresponding odors of amyl acetate and menthone. Whereas there were no overall hemispheric differences for pyridine odor, activation in men was R > L hemisphere. Although absolute activation in both L and R hemispheres in response to banana odor imagination and amyl acetate smell was men > women, the ratio of L to R activation was women > men. In hyposmic patients studied by FLASH fMRI, activation to banana odor imagination and amyl acetate smell was L > R hemisphere both before and after

  16. Selective attention to phonology dynamically modulates initial encoding of auditory words within the left hemisphere.

    Science.gov (United States)

    Yoncheva, Yuliya; Maurer, Urs; Zevin, Jason D; McCandliss, Bruce D

    2014-08-15

    Selective attention to phonology, i.e., the ability to attend to sub-syllabic units within spoken words, is a critical precursor to literacy acquisition. Recent functional magnetic resonance imaging evidence has demonstrated that a left-lateralized network of frontal, temporal, and posterior language regions, including the visual word form area, supports this skill. The current event-related potential (ERP) study investigated the temporal dynamics of selective attention to phonology during spoken word perception. We tested the hypothesis that selective attention to phonology dynamically modulates stimulus encoding by recruiting left-lateralized processes specifically while the information critical for performance is unfolding. Selective attention to phonology was captured by manipulating listening goals: skilled adult readers attended to either rhyme or melody within auditory stimulus pairs. Each pair superimposed rhyming and melodic information ensuring identical sensory stimulation. Selective attention to phonology produced distinct early and late topographic ERP effects during stimulus encoding. Data-driven source localization analyses revealed that selective attention to phonology led to significantly greater recruitment of left-lateralized posterior and extensive temporal regions, which was notably concurrent with the rhyme-relevant information within the word. Furthermore, selective attention effects were specific to auditory stimulus encoding and not observed in response to cues, arguing against the notion that they reflect sustained task setting. Collectively, these results demonstrate that selective attention to phonology dynamically engages a left-lateralized network during the critical time-period of perception for achieving phonological analysis goals. These findings suggest a key role for selective attention in on-line phonological computations. Furthermore, these findings motivate future research on the role that neural mechanisms of attention may

  17. Reward-system effect and “left hemispheric unbalance”: a comparison between drug addiction and high-BAS healthy subjects on gambling behavior

    Directory of Open Access Journals (Sweden)

    Roberta Finocchiaro

    2015-04-01

    Full Text Available Recent studies show the similarity of reward-related neurocircuitry and behavioral patterns between pathological gamblers and substance addictive patients. Evidences proved that pathological gambling (PG and Substance Use Disorders (SUD are associated with deficits in frontal lobe function and that they show similar behaviors to that of patients with bilateral VMPFC lesions. The present article aimed to compare the results of two studies concerning the relationship between the Behavioral Activation System (BAS and the hemispheric lateralisation effect that supports the gambling behavior in addiction disease. In the two studies we considered a group of Cocaine Addictive (CA patients and high-BAS healthy subjects who were tested using the Iowa Gambling Task. Also metacognitive questionary and alpha band modulation were considered. It was found that the “left hemisphere unbalance” may be considered as a critical marker of dysfunctional decision-making in addictive behaviors (drug addiction and gambling behaviours and a factor able to explain the tendency to opt in favor of more reward-related conditions.

  18. Another look at category effects on colour perception and their left hemispheric lateralisation: no evidence from a colour identification task.

    Science.gov (United States)

    Suegami, Takashi; Aminihajibashi, Samira; Laeng, Bruno

    2014-05-01

    The present study aimed to replicate category effects on colour perception and their lateralisation to the left cerebral hemisphere (LH). Previous evidence for lateralisation of colour category effects has been obtained with tasks where a differently coloured target was searched within a display and participants reported the lateral location of the target. However, a left/right spatial judgment may yield LH-laterality effects per se. Thus, we employed an identification task that does not require a spatial judgment and used the same colour set that previously revealed LH-lateralised category effects. The identification task was better performed with between-category colours than with within-category task both in terms of accuracy and latency, but such category effects were bilateral or RH-lateralised, and no evidence was found for LH-laterality effects. The accuracy scores, moreover, indicated that the category effects derived from low sensitivities for within-blue colours and did not reflect the effects of categorical structures on colour perception. Furthermore, the classic "category effects" were observed in participants' response biases, instead of sensitivities. The present results argue against both the LH-lateralised category effects on colour perception and the existence of colour category effects per se.

  19. Headache and Central Positioning Vertigo in a Middle Aged Female-a Case of Solitary Cerebellar Tuberculoma Involving Left Cerebellar Hemisphere

    Directory of Open Access Journals (Sweden)

    Shakya Bhattacharjee

    2012-03-01

    Full Text Available A 48 year old female presented with headache and an illusory sensation of spinning of head in respect to environment for last 8 weeks. Her head spinning or vertigo had no particular direction or not precipitated by any specific head posture. Headache is non- specific in nature and intensified in last few days.Her neurological examination revealed a central positional vertigo with horizontal gaze evoked nystagmus and ataxia. Her MRI scan brain showed the presence of a large solitary ring enhancing lesion in the left cerebellar hemisphere. The lesion was surgically excised and was examined histopathologicaliy that revealed a chronic inflammatory granuloma with caseation necrosis and multinucleated giant cells suggestive of tuberculosis

  20. Language in individuals with left hemisphere tumors: Is spontaneous speech analysis comparable to formal testing?

    Science.gov (United States)

    Rofes, Adrià; Talacchi, Andrea; Santini, Barbara; Pinna, Giampietro; Nickels, Lyndsey; Bastiaanse, Roelien; Miceli, Gabriele

    2018-01-31

    The relationship between spontaneous speech and formal language testing in people with brain tumors (gliomas) has been rarely studied. In clinical practice, formal testing is typically used, while spontaneous speech is less often evaluated quantitatively. However, spontaneous speech is quicker to sample and may be less prone to test/retest effects, making it a potential candidate for assessing language impairments when there is restricted time or when the patient is unable to undertake prolonged testing. To assess whether quantitative spontaneous speech analysis and formal testing detect comparable language impairments in people with gliomas. Specifically, we addressed (a) whether both measures detected comparable language impairments in our patient sample; and (b) which language levels, assessment times, and spontaneous speech variables were more often impaired in this subject group. Five people with left perisylvian gliomas performed a spontaneous speech task and a formal language assessment. Tests were administered before surgery, within a week after surgery, and seven months after surgery. Performance on spontaneous speech was compared with that of 15 healthy speakers. Language impairments were detected more often with both measures than with either measure independently. Lexical-semantic impairments were more common than phonological and grammatical impairments, and performance was equally impaired across assessment time points. Incomplete sentences and phonological paraphasias were the most common error types. In our sample both spontaneous speech analysis and formal testing detected comparable language impairments. Currently, we suggest that formal testing remains overall the better option, except for cases in which there are restrictions on testing time or the patient is too tired to undergo formal testing. In these cases, spontaneous speech may provide a viable alternative, particularly if automated analysis of spontaneous speech becomes more readily

  1. The Influence of Visual and Auditory Information on the Perception of Speech and Non-Speech Oral Movements in Patients with Left Hemisphere Lesions

    Science.gov (United States)

    Schmid, Gabriele; Thielmann, Anke; Ziegler, Wolfram

    2009-01-01

    Patients with lesions of the left hemisphere often suffer from oral-facial apraxia, apraxia of speech, and aphasia. In these patients, visual features often play a critical role in speech and language therapy, when pictured lip shapes or the therapist's visible mouth movements are used to facilitate speech production and articulation. This demands…

  2. Changes in regional cerebral blood flow in the right cortex homologous to left language areas are directly affected by left hemispheric damage in aphasic stroke patients: evaluation by Tc-ECD SPECT and novel analytic software.

    Science.gov (United States)

    Uruma, G; Kakuda, W; Abo, M

    2010-03-01

    The objective of this study was to clarify the influence of regional cerebral blood flow (rCBF) changes in language-relevant areas of the dominant hemisphere on rCBF in each region in the non-dominant hemisphere in post-stroke aphasic patients. The study subjects were 27 aphasic patients who suffered their first symptomatic stroke in the left hemisphere. In each subject, we measured rCBF by means of 99mTc-ethylcysteinate dimmer single photon emission computed tomography (SPECT). The SPECT images were analyzed by the statistical imaging analysis programs easy Z-score Imaging System (eZIS) and voxel-based stereotactic extraction estimation (vbSEE). Segmented into Brodmann Area (BA) levels, Regions of Interest (ROIs) were set in language-relevant areas bilaterally, and changes in the relative rCBF as average negative and positive Z-values were computed fully automatically. To assess the relationship between rCBF changes of each ROIs in the left and right hemispheres, the Spearman ranked correlation analysis and stepwise multiple regression analysis were applied. Globally, a negative and asymmetric influence of rCBF changes in the language-relevant areas of the dominant hemisphere on the right hemisphere was found. The rCBF decrease in left BA22 significantly influenced the rCBF increase in right BA39, BA40, BA44 and BA45. The results suggested that the chronic increase in rCBF in the right language-relevant areas is due at least in part to reduction in the trancallosal inhibitory activity of the language-dominant left hemisphere caused by the stroke lesion itself and that these relationships are not always symmetric.

  3. Increased emergence of alpha activity over the left but not the right temporal lobe within a dark acoustic chamber: differential response of the left but not the right hemisphere to transcerebral magnetic fields.

    Science.gov (United States)

    Persinger, M A

    1999-11-01

    The percentages of alpha activity per minute over the left and right temporal lobes were measured for the first and second successive 15-min intervals while subjects wore opaque goggles within an acoustic chamber. A weak (5 microT), burst-firing magnetic field was presented during this period for 1 s every 4 s primarily over the left or the right cerebral hemisphere. The results indicated that the left temporal lobe became less vigilant between the first and second 15 min while the right temporal lobe did not. When standardized scores for each subject's measures over time and across hemispheres were employed, increased alpha time over the left temporal lobe relative to the right temporal lobe was observed only when the transcerebral magnetic field was applied over the left hemisphere. Stimulation of the right hemisphere did not evoke this discrepancy. The detection of the effects of this specific complex magnetic field upon electroencephalographic activity may be more probable when the subjects are exposed to partial sensory deprivation.

  4. A supervised framework for lesion segmentation and automated VLSM analyses in left hemispheric stroke

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    Dorian Pustina

    2015-05-01

    Full Text Available INTRODUCTION: Voxel-based lesion-symptom mapping (VLSM is conventionally performed using skill and knowledge of experts to manually delineate brain lesions. This process requires time, and is likely to have substantial inter-rater variability. Here, we propose a supervised machine learning framework for lesion segmentation capable of learning from a single modality and existing manual segmentations in order to delineate lesions in new patients. METHODS: Data from 60 patients with chronic stroke aphasia were utilized in the study (age: 59.7±11.5yrs, post-stroke interval: 5±2.9yrs, male/female ratio: 34/26. Using a single T1 image of each subject, additional features were created that provided complementary information, such as, difference from template, tissue segmentation, brain asymmetries, gradient magnitude, and deviances of these images from 80 age and gender matched controls. These features were fed into MRV-NRF (multi-resolution voxel-wise neighborhood random forest; Tustison et al., 2014 prediction algorithm implemented in ANTsR (Avants, 2015. The algorithm incorporates information from each voxel and its surrounding neighbors from all above features, in a hierarchy of random forest predictions from low to high resolution. The validity of the framework was tested with a 6-fold cross validation (i.e., train from 50 subjects, predict 10. The process was repeated ten times, producing ten segmentations for each subject, from which the average solution was binarized. Predicted lesions were compared to manually defined lesions, and VLSM models were built on 4 language measures: repetition and comprehension subscores from the WAB (Kertesz, 1982, WAB-AQ, and PNT naming accuracy (Roach, Schwartz, Martin, Grewal, & Brecher, 1996. RESULTS: Manual and predicted lesion size showed high correlation (r=0.96. Compared to manual lesions, the predicted lesions had a dice overlap of 0.72 (±0.14 STD, a case-wise maximum distance (Hausdorff of 21mm (±16

  5. Continuous theta burst stimulation (cTBS on left cerebellar hemisphere affects mental rotation tasks during music listening.

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    Silvia Picazio

    Full Text Available Converging evidence suggests an association between spatial and music domains. A cerebellar role in music-related information processing as well as in spatial-temporal tasks has been documented. Here, we investigated the cerebellar role in the association between spatial and musical domains, by testing performances in embodied (EMR or abstract (AMR mental rotation tasks of subjects listening Mozart Sonata K.448, which is reported to improve spatial-temporal reasoning, in the presence or in the absence of continuous theta burst stimulation (cTBS of the left cerebellar hemisphere. In the absence of cerebellar cTBS, music listening did not influence either MR task, thus not revealing a "Mozart Effect". Cerebellar cTBS applied before musical listening made subjects faster (P = 0.005 and less accurate (P = 0.005 in performing the EMR but not the AMR task. Thus, cerebellar inhibition by TBS unmasked the effect of musical listening on motor imagery. These data support a coupling between music listening and sensory-motor integration in cerebellar networks for embodied representations.

  6. THE IMPACT OF LEFT HEMISPHERE STROKE ON FORCE CONTROL WITH FAMILIAR AND NOVEL OBJECTS: NEUROANATOMIC SUBSTRATES AND RELATIONSHIP TO APRAXIA

    Science.gov (United States)

    Dawson, Amanda M.; Buxbaum, Laurel J.; Duff, Susan V.

    2010-01-01

    Fingertip force scaling for lifting objects frequently occurs in anticipation of finger contact. An ongoing question concerns the types of memories that are used to inform predictive control. Object-specific information such as weight may be stored and retrieved when previously encountered objects are lifted again. Alternatively, visual size and shape cues may provide estimates of object density each time objects are encountered. We reasoned that differences in performance with familiar versus novel objects would provide support for the former possibility. Anticipatory force production with both familiar and novel objects was assessed in 6 left hemisphere stroke patients, 2 of whom exhibited deficient actions with familiar objects (ideomotor apraxia; IMA), along with 5 control subjects. In contrast to healthy controls and stroke participants without IMA, participants with IMA displayed poor anticipatory scaling with familiar objects. However, like the other groups, IMA participants learned to differentiate fingertip forces with repeated lifts of both familiar and novel objects. Finally, there was a significant correlation between damage to the inferior parietal and superior and middle temporal lobes, and impaired anticipatory control for familiar objects. These data support the hypotheses that anticipatory control during lifts of familiar objects in IMA patients are based on object-specific memories, and that the ventro-dorsal stream is involved in the long-term storage of internal models used for anticipatory scaling during object manipulation. PMID:19945445

  7. Left and right brain-oriented hemisity subjects show opposite behavioral preferences

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    Bruce Eldine Morton

    2012-11-01

    Full Text Available Introduction: Recently, three independent, intercorrelated biophysical measures have provided the first quantitative measures of a binary form of behavioral laterality called Hemisity, a term referring to inherent opposite right or left brain-oriented differences in thinking and behavioral styles. Crucially, the right or left brain-orientation of individuals assessed by these methods was later found to be essentially congruent with the thicker side of their ventral gyrus of the anterior cingulate cortex (vgACC as revealed by a 3 minute MRI procedure. Laterality of this putative executive structural element has thus become the primary standard defining individual hemisity. Methods: Here, the behavior of 150 subjects, whose hemisity had been calibrated by MRI, was assessed using five MRI-calibrated preference questionnaires, two of which were new.Results: Right and left brain-oriented subjects selected opposite answers (p > 0.05 for 47 of the 107 either-or, forced choice type preference questionnaire items. Hemisity subtype preference differences were present in several areas. They were in: a. logical orientation, b. type of consciousness, c. fear level and sensitivity, d. social-professional orientation, and e. pair bonding-spousal dominance style.Conclusions: The right and left brain-oriented hemisity subtype subjects, sorted on the anatomical basis of upon which brain side their vgACC was thickest, showed numerous significant differences in their either-or type of behavioral preferences.

  8. Asymmetry and symmetry in brain waves from dolphin left and right hemispheres: some observations after anesthesia, during quiescent hanging behavior, and during visual obstruction.

    Science.gov (United States)

    Ridgway, S H

    2002-01-01

    Studies of sleep in cetaceans (whales, dolphins, and porpoises), substantiated by electrophysiological data, are rare with the great majority of observations having been made by one group from Russia. This group employed hard-wired recording with low-noise cables for their EEG observations, whereas our report describes behavioral and EEG observations of dolphin sleep using telemetry. Marked asymmetry of the EEG was observed during behavioral sleep posture. At different times synchronized slow waves appeared in both left and right brain hemispheres concurrently with lower voltage, faster, desynchronized EEG activity in the opposite hemisphere. On the other hand, during one brief period of sleep behavior, sleep-like EEG activity appeared on leads from both hemispheres. When the animal was exposed to a loud sound, it woke with lower voltage, faster, relatively symmetrical, desynchronized EEG activity appearing from both hemispheres. Additionally, the EEG appeared relatively desynchronized and symmetrical between the two hemispheres when the animal was awake during recovery from pentothal-halothane anesthesia as well as during waking periods when one or both of the animal's eyes were covered by an opaque rubber suction cup. Copyright 2002 S. Karger AG, Basel

  9. Music and Stroke Rehabilitation: A Narrative Synthesis of the Music-Based Treatments used to Rehabilitate Disorders of Speech and Language following Left-Hemispheric Stroke

    OpenAIRE

    Kevin Draper

    2016-01-01

    Stroke is a leading cause of long-term disability. A stroke can damage areas of the brain associated with communication, resulting in speech and language disorders. Such disorders are frequently acquired impairments from left-hemispheric stroke. Music-based treatments have been implemented, and researched in practice, for the past thirty years; however, the number of published reports reviewing these treatments is limited. This paper uses the four elements of the narrative synthesis framework...

  10. Bilingualism yields language-specific plasticity in left hemisphere's circuitry for learning to read in young children.

    Science.gov (United States)

    Jasińska, K K; Berens, M S; Kovelman, I; Petitto, L A

    2017-04-01

    How does bilingual exposure impact children's neural circuitry for learning to read? Theories of bilingualism suggests that exposure to two languages may yield a functional and neuroanatomical adaptation to support the learning of two languages (Klein et al., 2014). To test the hypothesis that this neural adaptation may vary as a function of structural and orthographic characteristics of bilinguals' two languages, we compared Spanish-English and French-English bilingual children, and English monolingual children, using functional Near Infrared Spectroscopy neuroimaging (fNIRS, ages 6-10, N =26). Spanish offers consistent sound-to-print correspondences ("phonologically transparent" or "shallow"); such correspondences are more opaque in French and even more opaque in English (which has both transparent and "phonologically opaque" or "deep" correspondences). Consistent with our hypothesis, both French- and Spanish-English bilinguals showed hyperactivation in left posterior temporal regions associated with direct sound-to-print phonological analyses and hypoactivation in left frontal regions associated with assembled phonology analyses. Spanish, but not French, bilinguals showed a similar effect when reading Irregular words. The findings inform theories of bilingual and cross-linguistic literacy acquisition by suggesting that structural characteristics of bilinguals' two languages and their orthographies have a significant impact on children's neuro-cognitive architecture for learning to read. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Selected Gray Matter Volumes and Gender but Not Basal Ganglia nor Cerebellum Gyri Discriminate Left Versus Right Cerebral Hemispheres: Multivariate Analyses in human Brains at 3T.

    Science.gov (United States)

    Roldan-Valadez, Ernesto; Suarez-May, Marcela A; Favila, Rafael; Aguilar-Castañeda, Erika; Rios, Camilo

    2015-07-01

    Interest in the lateralization of the human brain is evident through a multidisciplinary number of scientific studies. Understanding volumetric brain asymmetries allows the distinction between normal development stages and behavior, as well as brain diseases. We aimed to evaluate volumetric asymmetries in order to select the best gyri able to classify right- versus left cerebral hemispheres. A cross-sectional study performed in 47 right-handed young-adults healthy volunteers. SPM-based software performed brain segmentation, automatic labeling and volumetric analyses for 54 regions involving the cerebral lobes, basal ganglia and cerebellum from each cerebral hemisphere. Multivariate discriminant analysis (DA) allowed the assembling of a predictive model. DA revealed one discriminant function that significantly differentiated left vs. right cerebral hemispheres: Wilks' λ = 0.008, χ(2) (9) = 238.837, P vision and language; our findings favored the concept that lateralization has been evolutionary favored by mental processes increasing cognitive efficiency and brain capacity. © 2015 Wiley Periodicals, Inc.

  12. Hemispheric specialisation in selective attention and short-term memory: A fine-coarse model of left and right ear disadvantages

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    John E. Marsh

    2013-12-01

    Full Text Available Serial short-term memory is impaired by irrelevant sound, particularly when the sound changes acoustically. This acoustic effect is larger when the sound is presented to the left compared to the right ear (a left-ear disadvantage. Serial memory appears relatively insensitive to distraction from the semantic properties of a background sound. In contrast, short-term free recall of semantic-category exemplars is impaired by the semantic properties of background speech and relatively insensitive to the sound’s acoustic properties. This semantic effect is larger when the sound is presented to the right compared to the left ear (a right-ear disadvantage. In this paper, we outline a speculative neurocognitive fine-coarse model of these hemispheric differences in relation to short-term memory and selective attention, and explicate empirical directions in which this model can be critically evaluated.

  13. Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning.

    Science.gov (United States)

    Waters, Sheena; Wiestler, Tobias; Diedrichsen, Jörn

    2017-08-02

    What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere. SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex

  14. Hemispheric specialization in dogs for processing different acoustic stimuli.

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    Marcello Siniscalchi

    Full Text Available Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions.

  15. Performance of language tasks in patients with ruptured aneurysm of the left hemisphere worses in the post-surgical evaluation

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    Ana Cláudia C. Vieira

    2016-08-01

    Full Text Available ABSTRACT Sub-arachnoid hemorrhage (SAH promotes impairment of upper cortical functions. However, few information is available emphasizing changes in language after aneurismal SAH and aneurysm location influence. Objective To assess the language and verbal fluency performance in aneurismal SAH pre- and post-surgery in patients caused by an aneurysm of the anterior communicating artery (AcomA, left middle cerebral artery (L-MCA and left posterior comunicating artery (L-PcomA. Methods Assessment in 79 patients with SAH, on two occasions: pre- and post surgical treatment. They were divided into three groups by the aneurysms’ location. Results Deterioration is detected in the performance of all patients during the post-surgical period; L-MCA aneurysm patients displayed a reduction in verbal naming and fluency; L-PcomA patients deteriorated in the written language and fluency tasks. Conclusion After the surgical procedure the patients decreased in various language tasks and these differences in performance being directly related to the location of the aneurysm.

  16. Linkage analysis in a Dutch population isolate shows no major gene for left-handedness or atypical language lateralization.

    Science.gov (United States)

    Somers, Metten; Ophoff, Roel A; Aukes, Maartje F; Cantor, Rita M; Boks, Marco P; Dauwan, Meenakshi; de Visser, Kees L; Kahn, René S; Sommer, Iris E

    2015-06-10

    Cerebral dominance of language function and hand preference are suggested to be heritable traits with possible shared genetic background. However, joined genetic studies of these traits have never been conducted. We performed a genetic linkage study in 37 multigenerational human pedigrees of both sexes (consisting of 355 subjects) enriched with left-handedness in which we also measured language lateralization. Hand preference was measured with the Edinburgh Handedness Inventory, and language lateralization was measured with functional transcranial Doppler during language production. The estimated heritability of left-handedness and language lateralization in these pedigrees is 0.24 and 0.31, respectively. A parametric major gene model was tested for left-handedness. Nonparametric analyses were performed for left-handedness, atypical lateralization, and degree of language lateralization. We did not observe genome-wide evidence for linkage in the parametric or nonparametric analyses for any of the phenotypes tested. However, multiple regions showed suggestive evidence of linkage. The parametric model showed suggestive linkage for left-handedness in the 22q13 region [heterogeneity logarithm of odds (HLOD) = 2.18]. Nonparametric multipoint analysis of left-handedness showed suggestive linkage in the same region [logarithm of odds (LOD) = 2.80]. Atypical language lateralization showed suggestive linkage in the 7q34 region (LODMax = 2.35). For strength of language lateralization, we observed suggestive linkage in the 6p22 (LODMax = 2.54), 7q32 (LODMax = 1.93), and 9q33 (LODMax = 2.10) regions. We did not observe any overlap of suggestive genetic signal between handedness and the extent of language lateralization. The absence of significant linkage argues against the presence of a major gene coding for both traits; rather, our results are suggestive of these traits being two independent polygenic complex traits. Copyright © 2015 the authors 0270-6474/15/358730-07$15.00/0.

  17. Automatic segmentation of short association bundles using a new multi-subject atlas of the left hemisphere fronto-parietal brain connections.

    Science.gov (United States)

    Guevara, M; Seguel, D; Roman, C; Duclap, D; Lebois, A; Le Bihan; Mangin, J-F; Poupon, C; Guevara, P

    2015-08-01

    Human brain connection map is far from being complete. In particular the study of the superficial white matter (SWM) is an unachieved task. Its description is essential for the understanding of human brain function and the study of the pathogenesis associated to it. In this work we developed a method for the automatic creation of a SWM bundle multi-subject atlas. The atlas generation method is based on a cortical parcellation for the extraction of fibers connecting two different gyri. Then, an intra-subject fiber clustering is applied, in order to divide each bundle into sub-bundles with similar shape. After that, a two-step inter-subject fiber clustering is used in order to find the correspondence between the sub-bundles across the subjects, fuse similar clusters and discard the outliers. The method was applied to 40 subjects of a high quality HARDI database, focused on the left hemisphere fronto-parietal and insula brain regions. We obtained an atlas composed of 44 bundles connecting 22 pair of ROIs. Then the atlas was used to automatically segment 39 new subjects from the database.

  18. Feasibility of the cognitive assessment scale for stroke patients (CASP) vs. MMSE and MoCA in aphasic left hemispheric stroke patients.

    Science.gov (United States)

    Barnay, J-L; Wauquiez, G; Bonnin-Koang, H Y; Anquetil, C; Pérennou, D; Piscicelli, C; Lucas-Pineau, B; Muja, L; le Stunff, E; de Boissezon, X; Terracol, C; Rousseaux, M; Bejot, Y; Binquet, C; Antoine, D; Devilliers, H; Benaim, C

    2014-01-01

    Post-stroke aphasia makes it difficult to assess cognitive deficiencies. We thus developed the CASP, which can be administered without using language. Our objective was to compare the feasibility of the CASP, the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) in aphasic stroke patients. All aphasic patients consecutively admitted to seven French rehabilitation units during a 4-month period after a recent first left hemispheric stroke were assessed with CASP, MMSE and MoCA. We determined the proportion of patients in whom it was impossible to administer at least one item from these 3 scales, and compared their administration times. Forty-four patients were included (age 64±15, 26 males). The CASP was impossible to administer in eight of them (18%), compared with 16 for the MMSE (36%, P=0.05) and 13 for the MoCA (30%, P=0.21, NS). It was possible to administer the CASP in all of the patients with expressive aphasia, whereas the MMSE and the MoCA could not be administered. Administration times were longer for the CASP (13±4min) than for the MMSE (8±3min, P<10(-6)) and the MoCA (11±5min, P=0.23, NS). The CASP is more feasible than the MMSE and the MoCA in aphasic stroke patients. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  19. Reading the wrong way with the right hemisphere.

    Science.gov (United States)

    Waldie, Karen E; Haigh, Charlotte E; Badzakova-Trajkov, Gjurgjica; Buckley, Jude; Kirk, Ian J

    2013-07-17

    Reading is a complex process, drawing on a variety of brain functions in order to link symbols to words and concepts. The three major brain areas linked to reading and phonological analysis include the left temporoparietal region, the left occipitotemporal region and the inferior frontal gyrus. Decreased activation of the left posterior language system in dyslexia is well documented but there is relatively limited attention given to the role of the right hemisphere. The current study investigated differences in right and left hemisphere activation between individuals with dyslexia and non-impaired readers in lexical decision tasks (regular words, irregular words, pseudowords) during functional Magnetic Resonance Imaging (fMRI). Results revealed the expected hypo-activation in the left posterior areas in those with dyslexia but also areas of overactivation in the right hemisphere. During pseudoword decisions, for example, adults with dyslexia showed more right inferior occipital gyrus activation than controls. In general the increased activation of left-hemisphere language areas found in response to both regular and pseudowords was absent in dyslexics. Laterality indices showed that while controls showed left lateralised activation of the temporal lobe during lexical decision making, dyslexic readers showed right activation. Findings will inform theories of reading and will have implications for the design of reading interventions.

  20. Reading the Wrong Way with the Right Hemisphere

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    Ian J. Kirk

    2013-07-01

    Full Text Available Reading is a complex process, drawing on a variety of brain functions in order to link symbols to words and concepts. The three major brain areas linked to reading and phonological analysis include the left temporoparietal region, the left occipitotemporal region and the inferior frontal gyrus. Decreased activation of the left posterior language system in dyslexia is well documented but there is relatively limited attention given to the role of the right hemisphere. The current study investigated differences in right and left hemisphere activation between individuals with dyslexia and non-impaired readers in lexical decision tasks (regular words, irregular words, pseudowords during functional Magnetic Resonance Imaging (fMRI. Results revealed the expected hypo-activation in the left posterior areas in those with dyslexia but also areas of overactivation in the right hemisphere. During pseudoword decisions, for example, adults with dyslexia showed more right inferior occipital gyrus activation than controls. In general the increased activation of left-hemisphere language areas found in response to both regular and pseudowords was absent in dyslexics. Laterality indices showed that while controls showed left lateralised activation of the temporal lobe during lexical decision making, dyslexic readers showed right activation. Findings will inform theories of reading and will have implications for the design of reading interventions.

  1. Processing of unconventional stimuli requires the recruitment of the non-specialized hemisphere

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    Yoed Nissan Kenett

    2015-02-01

    Full Text Available In the present study we investigate hemispheric processing of conventional and unconventional visual stimuli in the context of visual and verbal creative ability. In Experiment 1, we studied two unconventional visual recognition tasks – Mooney face and objects' silhouette recognition – and found a significant relationship between measures of verbal creativity and unconventional face recognition. In Experiment 2 we used the split visual field paradigm to investigate hemispheric processing of conventional and unconventional faces and its relation to verbal and visual characteristics of creativity. Results showed that while conventional faces were better processed by the specialized right hemisphere, unconventional faces were better processed by the non-specialized left hemisphere. In addition, only unconventional face processing by the non-specialized left hemisphere was related to verbal and visual measures of creative ability. Our findings demonstrate the role of the non-specialized hemisphere in processing unconventional stimuli and how it relates to creativity.

  2. Apraxia in left-handers.

    Science.gov (United States)

    Goldenberg, Georg

    2013-08-01

    In typical right-handed patients both apraxia and aphasia are caused by damage to the left hemisphere, which also controls the dominant right hand. In left-handed subjects the lateralities of language and of control of the dominant hand can dissociate. This permits disentangling the association of apraxia with aphasia from that with handedness. Pantomime of tool use, actual tool use and imitation of meaningless hand and finger postures were examined in 50 consecutive left-handed subjects with unilateral hemisphere lesions. There were three aphasic patients with pervasive apraxia caused by left-sided lesions. As the dominant hand is controlled by the right hemisphere, they constitute dissociations of apraxia from handedness. Conversely there were also three patients with pervasive apraxia caused by right brain lesions without aphasia. They constitute dissociations of apraxia from aphasia. Across the whole group of patients dissociations from handedness and from aphasia were observed for all manifestations of apraxia, but their frequency depended on the type of apraxia. Defective pantomime and defective tool use occurred rarely without aphasia, whereas defective imitation of hand, but not finger, postures was more frequent after right than left brain damage. The higher incidence of defective imitation of hand postures in right brain damage was mainly due to patients who had also hemi-neglect. This interaction alerts to the possibility that the association of right hemisphere damage with apraxia has to do with spatial aptitudes of the right hemisphere rather than with its control of the dominant left hand. Comparison with data from right-handed patients showed no differences between the severity of apraxia for imitation of hand or finger postures, but impairment on pantomime of tool use was milder in apraxic left-handers than in apraxic right-handers. This alleviation of the severity of apraxia corresponded with a similar alleviation of the severity of aphasia as

  3. Crossed Non-Dominant Hemisphere Syndrome in a Right-Hander

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    M. Fujimori

    1994-01-01

    Full Text Available A right-handed patient with a large left temporo-parietal infarction manifested various non-dominant hemisphere signs. He had two left-handed children. On neurobehavioural examinations, he did not show aphasia or ideomotor apraxia, but did show hemispatial neglect, spatial agraphia, constructional apraxia, auditory and tactile extinction, anosodiaphoria and affective changes, all of which are usually observed after right hemispheric damage. We conclude that he has a reversed cerebral laterality of cognitive functions and showed crossed non-dominant hemisphere syndrome.

  4. Language localization in cases of left temporal lobe arachnoid cyst : Evidence against interhemispheric reorganization

    NARCIS (Netherlands)

    Stowe, LA; Go, KG; Pruim, J; den Dunnen, W; Meiners, LC; Paans, AMJ

    2000-01-01

    We investigated whether left-hemisphere arachnoid cysts lead to reorganization of the language function using PET. A group analysis demonstrated that patients showed no more right-hemisphere activation than a matched control group. Several patients had clear language localizations in the left

  5. Speech and the Right Hemisphere

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    E. M. R. Critchley

    1991-01-01

    Full Text Available Two facts are well recognized: the location of the speech centre with respect to handedness and early brain damage, and the involvement of the right hemisphere in certain cognitive functions including verbal humour, metaphor interpretation, spatial reasoning and abstract concepts. The importance of the right hemisphere in speech is suggested by pathological studies, blood flow parameters and analysis of learning strategies. An insult to the right hemisphere following left hemisphere damage can affect residual language abilities and may activate non-propositional inner speech. The prosody of speech comprehension even more so than of speech production—identifying the voice, its affective components, gestural interpretation and monitoring one's own speech—may be an essentially right hemisphere task. Errors of a visuospatial type may occur in the learning process. Ease of learning by actors and when learning foreign languages is achieved by marrying speech with gesture and intonation, thereby adopting a right hemisphere strategy.

  6. Speech and the right hemisphere.

    Science.gov (United States)

    Critchley, E M

    1991-01-01

    Two facts are well recognized: the location of the speech centre with respect to handedness and early brain damage, and the involvement of the right hemisphere in certain cognitive functions including verbal humour, metaphor interpretation, spatial reasoning and abstract concepts. The importance of the right hemisphere in speech is suggested by pathological studies, blood flow parameters and analysis of learning strategies. An insult to the right hemisphere following left hemisphere damage can affect residual language abilities and may activate non-propositional inner speech. The prosody of speech comprehension even more so than of speech production-identifying the voice, its affective components, gestural interpretation and monitoring one's own speech-may be an essentially right hemisphere task. Errors of a visuospatial type may occur in the learning process. Ease of learning by actors and when learning foreign languages is achieved by marrying speech with gesture and intonation, thereby adopting a right hemisphere strategy.

  7. Right Hemisphere Dominance in Visual Statistical Learning

    Science.gov (United States)

    Roser, Matthew E.; Fiser, Jozsef; Aslin, Richard N.; Gazzaniga, Michael S.

    2011-01-01

    Several studies report a right hemisphere advantage for visuospatial integration and a left hemisphere advantage for inferring conceptual knowledge from patterns of covariation. The present study examined hemispheric asymmetry in the implicit learning of new visual feature combinations. A split-brain patient and normal control participants viewed…

  8. Hemispheric lateralization of linguistic prosody recognition in comparison to speech and speaker recognition.

    Science.gov (United States)

    Kreitewolf, Jens; Friederici, Angela D; von Kriegstein, Katharina

    2014-11-15

    Hemispheric specialization for linguistic prosody is a controversial issue. While it is commonly assumed that linguistic prosody and emotional prosody are preferentially processed in the right hemisphere, neuropsychological work directly comparing processes of linguistic prosody and emotional prosody suggests a predominant role of the left hemisphere for linguistic prosody processing. Here, we used two functional magnetic resonance imaging (fMRI) experiments to clarify the role of left and right hemispheres in the neural processing of linguistic prosody. In the first experiment, we sought to confirm previous findings showing that linguistic prosody processing compared to other speech-related processes predominantly involves the right hemisphere. Unlike previous studies, we controlled for stimulus influences by employing a prosody and speech task using the same speech material. The second experiment was designed to investigate whether a left-hemispheric involvement in linguistic prosody processing is specific to contrasts between linguistic prosody and emotional prosody or whether it also occurs when linguistic prosody is contrasted against other non-linguistic processes (i.e., speaker recognition). Prosody and speaker tasks were performed on the same stimulus material. In both experiments, linguistic prosody processing was associated with activity in temporal, frontal, parietal and cerebellar regions. Activation in temporo-frontal regions showed differential lateralization depending on whether the control task required recognition of speech or speaker: recognition of linguistic prosody predominantly involved right temporo-frontal areas when it was contrasted against speech recognition; when contrasted against speaker recognition, recognition of linguistic prosody predominantly involved left temporo-frontal areas. The results show that linguistic prosody processing involves functions of both hemispheres and suggest that recognition of linguistic prosody is based on

  9. When One Hemisphere Takes Control: Metacontrol in Pigeons (Columba livia)

    Science.gov (United States)

    Adam, Ruth; Güntürkün, Onur

    2009-01-01

    Background Vertebrate brains are composed of two hemispheres that receive input, compute, and interact to form a unified response. How the partially different processes of both hemispheres are integrated to create a single output is largely unknown. In some cases one hemisphere takes charge of the response selection – a process known as metacontrol. Thus far, this phenomenon has only been shown in a handful of studies with primates, mostly conducted in humans. Metacontrol, however, is even more relevant for animals like birds with laterally placed eyes and complete chiasmatic decussation since visual input to the hemispheres is largely different. Methodology/Principal Findings Homing pigeons (Columba livia) were trained with a color discrimination task. Each hemisphere was trained with a different color pair and therefore had a different experience. Subsequently, the pigeons were binocularly examined with two additional stimuli that combined the positive color of one hemisphere with a negative color that had been shown to the other, omitting the availability of a coherent solution and confronting the pigeons with a conflicting situation. Some of the pigeons responded to both stimuli, indicating that none of the hemispheres dominated the overall preference. Some birds, however, responded primarily to one of the conflicting stimuli, showing that they based their choice on the left- or right-monocularly learned color pair, indicating hemispheric metacontrol. Conclusions/Significance We could demonstrate for the first time that metacontrol is a widespread phenomenon that also exists in birds, and thus in principle requires no corpus callosum. Our results are closely similar to those in humans: monocular performance was higher than binocular one and animals displayed different modes of hemispheric dominance. Thus, metacontrol is a dynamic and widely distributed process that possibly constitutes a requirement for all animals with a bipartite brain to confront the

  10. Functional language shift to the right hemisphere in patients with language-eloquent brain tumors.

    Science.gov (United States)

    Krieg, Sandro M; Sollmann, Nico; Hauck, Theresa; Ille, Sebastian; Foerschler, Annette; Meyer, Bernhard; Ringel, Florian

    2013-01-01

    Language function is mainly located within the left hemisphere of the brain, especially in right-handed subjects. However, functional MRI (fMRI) has demonstrated changes of language organization in patients with left-sided perisylvian lesions to the right hemisphere. Because intracerebral lesions can impair fMRI, this study was designed to investigate human language plasticity with a virtual lesion model using repetitive navigated transcranial magnetic stimulation (rTMS). Fifteen patients with lesions of left-sided language-eloquent brain areas and 50 healthy and purely right-handed participants underwent bilateral rTMS language mapping via an object-naming task. All patients were proven to have left-sided language function during awake surgery. The rTMS-induced language errors were categorized into 6 different error types. The error ratio (induced errors/number of stimulations) was determined for each brain region on both hemispheres. A hemispheric dominance ratio was then defined for each region as the quotient of the error ratio (left/right) of the corresponding area of both hemispheres (ratio >1 = left dominant; ratio language-eloquent lesions showed a statistically significantly lower ratio than healthy participants concerning "all errors" and "all errors without hesitations", which indicates a higher participation of the right hemisphere in language function. Yet, there was no cortical region with pronounced difference in language dominance compared to the whole hemisphere. This is the first study that shows by means of an anatomically accurate virtual lesion model that a shift of language function to the non-dominant hemisphere can occur.

  11. Three-dimensional echocardiography with tissue harmonic imaging shows excellent reproducibility in assessment of left ventricular volumes

    DEFF Research Database (Denmark)

    Kim, Won Yong; Søgaard, Peter; Egeblad, Henrik

    2001-01-01

    on variance. Operator variability showed important contributions to total variance with the use of 2D echocardiography. The reproducibility of 3D echocardiography and tissue harmonic imaging is excellent and comparable to magnetic resonance imaging techniques; 3D echocardiography therefore should provide...

  12. Hemispheric lateralization of motor thresholds in relation to stuttering.

    Directory of Open Access Journals (Sweden)

    Per A Alm

    Full Text Available Stuttering is a complex speech disorder. Previous studies indicate a tendency towards elevated motor threshold for the left hemisphere, as measured using transcranial magnetic stimulation (TMS. This may reflect a monohemispheric motor system impairment. The purpose of the study was to investigate the relative side-to-side difference (asymmetry and the absolute levels of motor threshold for the hand area, using TMS in adults who stutter (n = 15 and in controls (n = 15. In accordance with the hypothesis, the groups differed significantly regarding the relative side-to-side difference of finger motor threshold (p = 0.0026, with the stuttering group showing higher motor threshold of the left hemisphere in relation to the right. Also the absolute level of the finger motor threshold for the left hemisphere differed between the groups (p = 0.049. The obtained results, together with previous investigations, provide support for the hypothesis that stuttering tends to be related to left hemisphere motor impairment, and possibly to a dysfunctional state of bilateral speech motor control.

  13. Bidirectional connectivity between hemispheres occurs at multiple levels in language processing but depends on sex.

    Science.gov (United States)

    Bitan, Tali; Lifshitz, Adi; Breznitz, Zvia; Booth, James R

    2010-09-01

    Our aim was to determine the direction of interhemispheric communication in a phonological task in regions involved in different levels of processing. Effective connectivity analysis was conducted on functional magnetic resonance imaging data from 39 children (ages 9-15 years) performing rhyming judgment on spoken words. The results show interaction between hemispheres at multiple levels. First, there is unidirectional transfer of information from right to left at the sensory level of primary auditory cortex. Second, bidirectional connections between superior temporal gyri (STGs) suggest a reciprocal cooperation between hemispheres at the level of phonological and prosodic processing. Third, a direct connection from right STG to left inferior frontal gyrus suggest that information processed in the right STG is integrated into the final stages of phonological segmentation required for the rhyming decision. Intrahemispheric connectivity from primary auditory cortex to STG was stronger in the left compared to the right hemisphere. These results support a model of cooperation between hemispheres, with asymmetric interhemispheric and intrahemispheric connectivity consistent with the left hemisphere specialization for phonological processing. Finally, we found greater interhemispheric connectivity in girls compared to boys, consistent with the hypothesis of a more bilateral representation of language in females than males. However, interhemispheric communication was associated with slow performance and low verbal intelligent quotient within girls. We suggest that females may have the potential for greater interhemispheric cooperation, which may be an advantage in certain tasks. However, in other tasks too much communication between hemispheres may interfere with task performance.

  14. Hemispheric asymmetry of the brain as a psycho-physiological basis of individual and typological features of the formation of a sense of humour

    Directory of Open Access Journals (Sweden)

    Shportun O.N.

    2016-05-01

    Full Text Available The article describes the psycho-physiological peculiarities of hemispheric asymmetry of the brain as the basis of individual and typological features of the formation of a sense of humour. The analysis of the impact of the functional brain hemispheric asymmetry on emotional, intellectual and physiological features of development of sense of humour in ontogeny is conducted. Analysis of studies of inter-hemispheric asymmetry of the brain makes it possible to ascertain the impact of the functioning of each hemisphere on the formation of the perception of humour. Studies show that in the process of developing of sense of humour, two functional hemispheres of the brain are involved. As the emotion of humour – is an intellectual emotion, and in the development of intelligence a lot of mental processes are involved, in the formation of humour two hemispheres of the brain are functioned. The right hemisphere is responsible for the emotional nature of humour (intonation, sound level of language, speed of response to a joke ..., the left hemisphere – for processing verbal information (content of the joke, category, purpose, content analysis .... After analysing the research of hemispheric functional asymmetry of the human brain, its psycho-physiological and neurochemical characteristics, it can be assumed that people with more developed left hemisphere in perceiving humour are more prone to displays of gelotophilia and “right hemisphere” people – show signs of gelotophobia and katagelasticism. Examining gender differences of hemisphere asymmetry of the brain, it can be argued that diagnosing sense of humour is important to take into account gender-specific functioning of hemispheres, because men have more clearly functioning the left hemisphere, and women – the right one. This fact of sexual peculiarities of functioning of inter-hemispheric asymmetry of the brain allows diagnosing objectively sense of humour, as well as different variations

  15. Processing of unconventional stimuli requires the recruitment of the non-specialized hemisphere.

    Science.gov (United States)

    Kenett, Yoed N; Anaki, David; Faust, Miriam

    2015-01-01

    In the present study we investigate hemispheric processing of conventional and unconventional visual stimuli in the context of visual and verbal creative ability. In Experiment 1, we studied two unconventional visual recognition tasks-Mooney face and objects' silhouette recognition-and found a significant relationship between measures of verbal creativity and unconventional face recognition. In Experiment 2 we used the split visual field (SVF) paradigm to investigate hemispheric processing of conventional and unconventional faces and its relation to verbal and visual characteristics of creativity. Results showed that while conventional faces were better processed by the specialized right hemisphere (RH), unconventional faces were better processed by the non-specialized left hemisphere (LH). In addition, only unconventional face processing by the non-specialized LH was related to verbal and visual measures of creative ability. Our findings demonstrate the role of the non-specialized hemisphere in processing unconventional stimuli and how it relates to creativity.

  16. Right hemispheric contributions to fine auditory temporal discriminations: high-density electrical mapping of the duration mismatch negativity (MMN

    Directory of Open Access Journals (Sweden)

    Pierfilippo De Sanctis

    2009-04-01

    Full Text Available That language processing is primarily a function of the left hemisphere has led to the supposition that auditory temporal discrimination is particularly well-tuned in the left hemisphere, since speech discrimination is thought to rely heavily on the registration of temporal transitions. However, physiological data have not consistently supported this view. Rather, functional imaging studies often show equally strong, if not stronger, contributions from the right hemisphere during temporal processing tasks, suggesting a more complex underlying neural substrate. The mismatch negativity (MMN component of the human auditory evoked-potential (AEP provides a sensitive metric of duration processing in human auditory cortex and lateralization of MMN can be readily assayed when sufficiently dense electrode arrays are employed. Here, the sensitivity of the left and right auditory cortex for temporal processing was measured by recording the MMN to small duration deviants presented to either the left or right ear. We found that duration deviants differing by just 15% (i.e. rare 115 ms tones presented in a stream of 100 ms tones elicited a significant MMN for tones presented to the left ear (biasing the right hemisphere. However, deviants presented to the right ear elicited no detectable MMN for this separation. Further, participants detected significantly more duration deviants and committed fewer false alarms for tones presented to the left ear during a subsequent psychophysical testing session. In contrast to the prevalent model, these results point to equivalent if not greater right hemisphere contributions to temporal processing of small duration changes.

  17. Left-right cortical asymmetries of regional cerebral blood flow during listening to words

    DEFF Research Database (Denmark)

    Nishizawa, Y; Olsen, T S; Larsen, B

    1982-01-01

    1. Regional cerebral blood flow (rCBF) was measured during rest and during listening to simple words. The xenon-133 intracarotid technique was used and results were obtained from 254 regions of seven right hemispheres and seven left hemispheres. The measurements were performed just after carotid...... of the entire hemisphere. The focal rCBF increases were localized to the superior part of the temporal regions, the prefrontal regions, the frontal eye fields, and the orbitofrontal regions. Significant asymmetries were found in particular in the superior temporal region with the left side showing a more...

  18. Perturbation of the left inferior frontal gyrus triggers adaptive plasticity in the right homologous area during speech production

    DEFF Research Database (Denmark)

    Hartwigsen, Gesa; Saur, Dorothee; Price, Cathy J

    2013-01-01

    The role of the right hemisphere in aphasia recovery after left hemisphere damage remains unclear. Increased activation of the right hemisphere has been observed after left hemisphere damage. This may simply reflect a release from transcallosal inhibition that does not contribute to language...... hemisphere lesion. Our findings lend further support to the notion that increased activation of homologous right hemisphere areas supports aphasia recovery after left hemisphere damage....

  19. Determination of hemispheric language dominance using functional MRI : comparison of visual and auditory stimuli

    International Nuclear Information System (INIS)

    Yoo, Ic Ryung; Ahn, Kook Jin; Lee, Jae Mun; Kim, Tae

    1999-01-01

    To assess the difference between auditory and visual stimuli when determining hemispheric language dominance by using functional MRI. In ten healthy adult volunteers (8 right-handed, 1 left-handed, 1 ambidextrous), motor language activation in axial slices of frontal lobe was mapped on a Simens 1.5T Vision Plus system using single-shot EPI. Series of 120 consecutive images per section were acquired during three cycles of task activation and rest. During each activation, a series of four syllables was delivered by means of both a visual and auditory method, and the volunteers were asked to mentally generate words starting with each syllable. In both in ferior frontal gyri and whole frontal lobes, lateralization indices were calculated from the activated pixels. We determined the language dominant hemisphere, and compared the results of the visual method and the auditory method. Seven right-handed persons were left-hemisphere dominant, and one left-handed and one ambidex-trous person were right-hemisphere dominant. Five of nine persons demonstrated larger lateralization indices with the auditory method than the visual method, while the remaining four showed larger lateralization indices with the visual method. No statistically significant difference was noted when comparing the results of the two methods(p>0.05). When determining hemispheric language dominance using functional MRI, the two methods are equally appropriate

  20. Determination of hemispheric language dominance using functional MRI : comparison of visual and auditory stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ic Ryung; Ahn, Kook Jin; Lee, Jae Mun [The Catholic Univ. of Korea, Seoul (Korea, Republic of); Kim, Tae [The Catholic Magnetic Resonance Research Center, Seoul (Korea, Republic of)

    1999-12-01

    To assess the difference between auditory and visual stimuli when determining hemispheric language dominance by using functional MRI. In ten healthy adult volunteers (8 right-handed, 1 left-handed, 1 ambidextrous), motor language activation in axial slices of frontal lobe was mapped on a Simens 1.5T Vision Plus system using single-shot EPI. Series of 120 consecutive images per section were acquired during three cycles of task activation and rest. During each activation, a series of four syllables was delivered by means of both a visual and auditory method, and the volunteers were asked to mentally generate words starting with each syllable. In both in ferior frontal gyri and whole frontal lobes, lateralization indices were calculated from the activated pixels. We determined the language dominant hemisphere, and compared the results of the visual method and the auditory method. Seven right-handed persons were left-hemisphere dominant, and one left-handed and one ambidex-trous person were right-hemisphere dominant. Five of nine persons demonstrated larger lateralization indices with the auditory method than the visual method, while the remaining four showed larger lateralization indices with the visual method. No statistically significant difference was noted when comparing the results of the two methods(p>0.05). When determining hemispheric language dominance using functional MRI, the two methods are equally appropriate.

  1. Right-hemispheric processing of non-linguistic word features

    DEFF Research Database (Denmark)

    Baumgaertner, Annette; Hartwigsen, Gesa; Roman Siebner, Hartwig

    2013-01-01

    -hemispheric homologues of classic left-hemispheric language areas may partly be due to processing nonlinguistic perceptual features of verbal stimuli. We used functional MRI (fMRI) to clarify the role of the right hemisphere in the perception of nonlinguistic word features in healthy individuals. Participants made......, in some instances, be driven by a "nonlinguistic perceptual processing" mode that focuses on nonlinguistic word features. This raises the possibility that stronger activation of right inferior frontal areas during language tasks in aphasic patients with left-hemispheric stroke may at least partially...

  2. Auditory middle latency responses differ in right- and left-handed subjects: an evaluation through topographic brain mapping.

    Science.gov (United States)

    Mohebbi, Mehrnaz; Mahmoudian, Saeid; Alborzi, Marzieh Sharifian; Najafi-Koopaie, Mojtaba; Farahani, Ehsan Darestani; Farhadi, Mohammad

    2014-09-01

    To investigate the association of handedness with auditory middle latency responses (AMLRs) using topographic brain mapping by comparing amplitudes and latencies in frontocentral and hemispheric regions of interest (ROIs). The study included 44 healthy subjects with normal hearing (22 left handed and 22 right handed). AMLRs were recorded from 29 scalp electrodes in response to binaural 4-kHz tone bursts. Frontocentral ROI comparisons revealed that Pa and Pb amplitudes were significantly larger in the left-handed than the right-handed group. Topographic brain maps showed different distributions in AMLR components between the two groups. In hemispheric comparisons, Pa amplitude differed significantly across groups. A left-hemisphere emphasis of Pa was found in the right-handed group but not in the left-handed group. This study provides evidence that handedness is associated with AMLR components in frontocentral and hemispheric ROI. Handedness should be considered an essential factor in the clinical or experimental use of AMLRs.

  3. Hemispheric differences in electrical and hemodynamic responses during hemifield visual stimulation with graded contrasts.

    Science.gov (United States)

    Si, Juanning; Zhang, Xin; Zhang, Yujin; Jiang, Tianzi

    2017-04-01

    A multimodal neuroimaging technique based on electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) was used with horizontal hemifield visual stimuli with graded contrasts to investigate the retinotopic mapping more fully as well as to explore hemispheric differences in neuronal activity, the hemodynamic response, and the neurovascular coupling relationship in the visual cortex. The fNIRS results showed the expected activation over the contralateral hemisphere for both the left and right hemifield visual stimulations. However, the EEG results presented a paradoxical lateralization, with the maximal response located over the ipsilateral hemisphere but with the polarity inversed components located over the contralateral hemisphere. Our results suggest that the polarity inversion as well as the latency advantage over the contralateral hemisphere cause the amplitude of the VEP over the contralateral hemisphere to be smaller than that over the ipsilateral hemisphere. Both the neuronal and hemodynamic responses changed logarithmically with the level of contrast in the hemifield visual stimulations. Moreover, the amplitudes and latencies of the visual evoked potentials (VEPs) were linearly correlated with the hemodynamic responses despite differences in the slopes.

  4. Influence of script direction on word processing modes in left and right visual fields.

    Science.gov (United States)

    Siéroff, Eric; Slama, Yael

    2017-11-15

    Word processing in left (LVF) and right (RVF) visual fields may be affected by left hemisphere activation during reading and by script direction. We evaluated the effect of script direction by presenting words in left-to-right (French) and right-to-left (Hebrew) scripts to bilingual French participants. Words of different lengths were presented in the LVF and the RVF in a naming task. Results showed (1) a stronger word length effect in the LVF than in the RVF in French, and no difference of word length effect between LVF and RVF in Hebrew; (2) a first-letter advantage only in the LVF in French and in the RVF in Hebrew, showing an effect of script direction on letter processing; and (3) a stronger advantage of external over internal letters in words presented in the LVF than in the RVF for both languages, showing a left hemisphere influence on letter activation. Thus, script direction and left hemisphere activation may affect different processes when reading words in LVF and RVF. Selective attention may orient and redistribute a processing "window" over the letter string according to script direction, and the modulation of attentional resources is influenced by left hemisphere activation.

  5. Hemispheric processing of memory is affected by sleep.

    Science.gov (United States)

    Monaghan, Padraic; Shaw, John J; Ashworth-Lord, Anneliese; Newbury, Chloe R

    2017-04-01

    Sleep is known to affect learning and memory, but the extent to which it influences behavioural processing in the left and right hemispheres of the brain is as yet unknown. We tested two hypotheses about lateralised effects of sleep on recognition memory for words: whether sleep reactivated recent experiences of words promoting access to the long-term store in the left hemisphere (LH), and whether sleep enhanced spreading activation differentially in semantic networks in the hemispheres. In Experiment 1, participants viewed lists of semantically related words, then slept or stayed awake for 12h before being tested on seen, unseen but related, or unrelated words presented to the left or the right hemisphere. Sleep was found to promote word recognition in the LH, and to spread activation equally within semantic networks in both hemispheres. Experiment 2 ensured that the results were not due to time of day effects influencing cognitive performance. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Game Utilization as a Media to Train the Balance of Left and Right Brain

    Directory of Open Access Journals (Sweden)

    Evan Wijaya

    2017-10-01

    Full Text Available Human have two brain hemispheres, left hemisphere and right hemisphere. Left hemisphere is used for processing language, words, numbers, equations, etc. Right hemisphere is used for processing creativity, imagination, music, color, etc. Every human should have balance between left and right hemisphere. One method that could be used for balancing brain hemispheres is to use left and right hands for using tools, writing, or typing. “Typing Rhythm” is a game for PC platform, the purpose of this game is for brain balancing exercise by typing lyric of a song while the song is played.

  7. Cardiac asystole associated with seizures of right hemispheric onset

    Directory of Open Access Journals (Sweden)

    Jennifer Chu

    2014-01-01

    Full Text Available Ictal asystole is frequently underrecognized despite being a potentially lethal condition. We report two cases of ictal asystole with right hemispheric onset. These cases are unique since previous literature reports that seizures associated with bradyarrhythmias typically arise from left hemispheric foci. These cases further underscore the importance of clinical vigilance and the need of an enhanced diagnostic biomarker.

  8. Comparison of neurodegeneration between right and left hippocampus area in rats

    Directory of Open Access Journals (Sweden)

    Arezo Nahavandi

    2015-02-01

    Conclusion: Our study showed different manifestations of depression after UCMS. It showed that UCMS could lead to mental depression. This study showed that the right hippocampus was more sensitive to stress than the left hippocampus. In fact, UCMS resulted in depression. The study showed that the right hippocampus was more sensitive to stress than the left hippocampus. Therefore, the main function of the right hemisphere, which is adaptation to the new environment, is disturbed more.

  9. Visual Similarity of Words Alone Can Modulate Hemispheric Lateralization in Visual Word Recognition: Evidence From Modeling Chinese Character Recognition.

    Science.gov (United States)

    Hsiao, Janet H; Cheung, Kit

    2016-03-01

    In Chinese orthography, the most common character structure consists of a semantic radical on the left and a phonetic radical on the right (SP characters); the minority, opposite arrangement also exists (PS characters). Recent studies showed that SP character processing is more left hemisphere (LH) lateralized than PS character processing. Nevertheless, it remains unclear whether this is due to phonetic radical position or character type frequency. Through computational modeling with artificial lexicons, in which we implement a theory of hemispheric asymmetry in perception but do not assume phonological processing being LH lateralized, we show that the difference in character type frequency alone is sufficient to exhibit the effect that the dominant type has a stronger LH lateralization than the minority type. This effect is due to higher visual similarity among characters in the dominant type than the minority type, demonstrating the modulation of visual similarity of words on hemispheric lateralization. Copyright © 2015 Cognitive Science Society, Inc.

  10. Bilateral cerebral hemispheric infarction associated with sildenafil citrate (Viagra) use.

    Science.gov (United States)

    Kim, K-K; Kim, D G; Ku, Y H; Lee, Y J; Kim, W-C; Kim, O J; Kim, H S

    2008-03-01

    Sildenafil citrate (Viagra) is one of the frequently prescribed drugs for men with erectile dysfunction. We describe a 52-year-old man with bilateral middle cerebral artery (MCA) territory infarction after sildenafil use. He ingested 100 mg of sildenafil and about 1 h later, he complained of chest discomfort, palpitation and dizziness followed by mental obtundation, global aphasia and left hemiparesis. Brain magnetic resonance imaging documented acute bilateral hemispheric infarction, and cerebral angiography showed occluded bilateral MCA. Despite significant bilateral MCA stenosis and cerebral infarction, systemic hypotension persisted for a day. We presume that cerebral infarction was caused by cardioembolism with sildenafil use.

  11. Directional information flows between brain hemispheres across waking, non-REM and REM sleep states: an EEG study.

    Science.gov (United States)

    Bertini, Mario; Ferrara, Michele; De Gennaro, Luigi; Curcio, Giuseppe; Moroni, Fabio; Babiloni, Claudio; Infarinato, Francesco; Rossini, Paolo Maria; Vecchio, Fabrizio

    2009-03-30

    The present electroencephalographic (EEG) study evaluated the hypothesis of a preferred directionality of communication flows between brain hemispheres across 24 h (i.e., during the whole daytime and nighttime), as an extension of a recent report showing changes in preferred directionality from pre-sleep wake to early sleep stages. Scalp EEGs were recorded in 10 normal volunteers during daytime wakefulness (eyes closed; first period: from 10:00 to 13:00 h; second period: from 14:00 to 18:00 h; third period: from 19:00 to 22:00 h) and nighttime sleep (four NREM-REM cycles). EEG rhythms of interest were delta (1-4 Hz), theta (5-7 Hz), alpha (8-11 Hz), sigma (12-15 Hz) and beta (16-28 Hz). The direction of the inter-hemispheric information flow was evaluated by computing the directed transfer function (DTF) from these EEG rhythms. Inter-hemispheric directional flows varied as a function of the state of consciousness (wake, NREM sleep, REM sleep) and in relation to different cerebral areas. During the daytime, alpha and beta rhythms conveyed inter-hemispheric signals with preferred Left-to-Right hemisphere direction in parietal and central areas, respectively. During the NREM sleep periods of nighttime, the direction of inter-hemispheric DTF information flows conveyed by central beta rhythms was again preponderant from Left-to-Right hemisphere in the stage 2, independent of cortical areas. No preferred direction emerged across the REM periods. These results support the hypothesis that specific directionality of communication flows between brain hemispheres is associated with wakefulness, NREM (particularly stage 2) and REM states during daytime and nighttime. They also reinforce the suggestive hypothesis of a relationship between inter-hemispheric directionality of EEG functional coupling and frequency of the EEG rhythms.

  12. Dyscalculia, dysgraphia, and left-right confusion from a left posterior peri-insular infarct.

    Science.gov (United States)

    Bhattacharyya, S; Cai, X; Klein, J P

    2014-01-01

    The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI) showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation.

  13. Dyscalculia, Dysgraphia, and Left-Right Confusion from a Left Posterior Peri-Insular Infarct

    Directory of Open Access Journals (Sweden)

    S. Bhattacharyya

    2014-01-01

    Full Text Available The Gerstmann syndrome of dyscalculia, dysgraphia, left-right confusion, and finger agnosia is generally attributed to lesions near the angular gyrus of the dominant hemisphere. A 68-year-old right-handed woman presented with sudden difficulty completing a Sudoku grid and was found to have dyscalculia, dysgraphia, and left-right confusion. Magnetic resonance imaging (MRI showed a focus of abnormal reduced diffusivity in the left posterior insula and temporoparietal operculum consistent with acute infarct. Gerstmann syndrome from an insular or peri-insular lesion has not been described in the literature previously. Pathological and functional imaging studies show connections between left posterior insular region and inferior parietal lobe. We postulate that the insula and operculum lesion disrupted key functional networks resulting in a pseudoparietal presentation.

  14. A vision of graded hemispheric specialization.

    Science.gov (United States)

    Behrmann, Marlene; Plaut, David C

    2015-11-01

    Understanding the process by which the cerebral hemispheres reach their mature functional organization remains challenging. We propose a theoretical account in which, in the domain of vision, faces and words come to be represented adjacent to retinotopic cortex by virtue of the need to discriminate among homogeneous exemplars. Orthographic representations are further constrained to be proximal to typically left-lateralized language-related information to minimize connectivity length between visual and language areas. As reading is acquired, orthography comes to rely more heavily (albeit not exclusively) on the left fusiform region to bridge vision and language. Consequently, due to competition from emerging word representations, face representations that were initially bilateral become lateralized to the right fusiform region (albeit, again, not exclusively). We review recent research that describes constraints that give rise to this graded hemispheric arrangement. We then summarize empirical evidence from a variety of studies (behavioral, evoked response potential, functional imaging) across different populations (children, adolescents, and adults; left handers and individuals with developmental dyslexia) that supports the claims that hemispheric lateralization is graded rather than binary and that this graded organization emerges dynamically over the course of development. Perturbations of this system either during development or in adulthood provide further insights into the principles governing hemispheric organization. © 2015 New York Academy of Sciences.

  15. Post-Surgical Language Reorganization Occurs in Tumors of the Dominant and Non-Dominant Hemisphere.

    Science.gov (United States)

    Avramescu-Murphy, M; Hattingen, E; Forster, M-T; Oszvald, A; Anti, S; Frisch, S; Russ, M O; Jurcoane, A

    2017-09-01

    Surgical resection of brain tumors may shift the location of cortical language areas. Studies of language reorganization primarily investigated left-hemispheric tumors irrespective of hemispheric language dominance. We used functional magnetic resonance imaging (fMRI) to investigate how tumors influence post-surgical language reorganization in relation to the dominant language areas. A total of, 17 patients with brain tumors (16 gliomas, one metastasis) in the frontotemporal and lower parietal lobes planned for awake surgery underwent pre-surgical and post-surgical language fMRI. Language activation post-to-pre surgery was evaluated visually and quantitatively on the statistically thresholded images on patient-by-patient basis. Results were qualitatively compared between three patient groups: temporal, with tumors in the dominant temporal lobe, frontal, with tumors in the dominant frontal lobe and remote, with tumors in the non-dominant hemisphere. Post-to-pre-surgical distributions of activated voxels changed in all except the one patient with metastasis. Changes were more pronounced in the dominant hemisphere for all three groups, showing increased number of activated voxels and also new activation areas. Tumor resection in the dominant hemisphere (frontal and temporal) shifted the activation from frontal towards temporal, whereas tumor resection in the non-dominant hemisphere shifted the activation from temporal towards frontal dominant areas. Resection of gliomas in the dominant and in the non-dominant hemisphere induces postsurgical shifts and increase in language activation, indicating that infiltrating gliomas have a widespread influence on the language network. The dominant hemisphere gained most of the language activation irrespective of tumor localization, possibly reflecting recovery of pre-surgical tumor-induced suppression of these activations.

  16. How do our brain hemispheres cooperate to avoid false memories?

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    Bergert, Susanne

    2013-02-01

    Memories are not always as reliable as they may appear. The occurrence of false memories can be reduced, however, by enhancing the cooperation between the two brain hemispheres. Yet is the communication from left to right hemisphere as helpful as the information transfer from right to left? To address this question, 72 participants were asked to learn 16 word lists. Applying the Deese-Roediger-McDermott paradigm, the words in each list were associated with an unpresented prototype word. In the test condition, learned words and corresponding prototypes were presented along with non-associated new words, and participants were asked to indicate which of the words they recognized. Crucially, both study and test words were projected to only one hemisphere in order to stimulate each hemisphere separately. It was found that false recognitions occurred significantly less often when the right hemisphere studied and the left hemisphere recognized the stimuli. Moreover, only the right-to-left direction of interhemispheric communication reduced false memories significantly, whereas left-to-right exchange did not. Further analyses revealed that the observed reduction of false memories was not due to an enhanced discrimination sensitivity, but to a stricter response bias. Hence, the data suggest that interhemispheric cooperation does not improve the ability to tell old and new apart, but rather evokes a conservative response tendency. Future studies may narrow down in which cognitive processing steps interhemispheric interaction can change the response criterion. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Northern Hemisphere forcing of Southern Hemisphere climate during the last deglaciation.

    Science.gov (United States)

    He, Feng; Shakun, Jeremy D; Clark, Peter U; Carlson, Anders E; Liu, Zhengyu; Otto-Bliesner, Bette L; Kutzbach, John E

    2013-02-07

    According to the Milankovitch theory, changes in summer insolation in the high-latitude Northern Hemisphere caused glacial cycles through their impact on ice-sheet mass balance. Statistical analyses of long climate records supported this theory, but they also posed a substantial challenge by showing that changes in Southern Hemisphere climate were in phase with or led those in the north. Although an orbitally forced Northern Hemisphere signal may have been transmitted to the Southern Hemisphere, insolation forcing can also directly influence local Southern Hemisphere climate, potentially intensified by sea-ice feedback, suggesting that the hemispheres may have responded independently to different aspects of orbital forcing. Signal processing of climate records cannot distinguish between these conditions, however, because the proposed insolation forcings share essentially identical variability. Here we use transient simulations with a coupled atmosphere-ocean general circulation model to identify the impacts of forcing from changes in orbits, atmospheric CO(2) concentration, ice sheets and the Atlantic meridional overturning circulation (AMOC) on hemispheric temperatures during the first half of the last deglaciation (22-14.3 kyr BP). Although based on a single model, our transient simulation with only orbital changes supports the Milankovitch theory in showing that the last deglaciation was initiated by rising insolation during spring and summer in the mid-latitude to high-latitude Northern Hemisphere and by terrestrial snow-albedo feedback. The simulation with all forcings best reproduces the timing and magnitude of surface temperature evolution in the Southern Hemisphere in deglacial proxy records. AMOC changes associated with an orbitally induced retreat of Northern Hemisphere ice sheets is the most plausible explanation for the early Southern Hemisphere deglacial warming and its lead over Northern Hemisphere temperature; the ensuing rise in atmospheric CO(2

  18. Circadian differences in hemisphere-linked spelling proficiencies.

    Science.gov (United States)

    Morton, L L; Diubaldo, D

    1995-03-01

    Male and female adolescents (N = 113) were assigned randomly to spelling instruction in either morning or afternoon groups for a school year. A spelling list (100 words) was administered at the beginning of the school year to obtain a sample of error responses and estimate proficiency. Although equally proficient, subjects tested in the afternoon showed more phonetically inappropriate errors, while those tested in the morning showed more phonetically appropriate errors. This error pattern is viewed as support for a more engaged left hemisphere in the morning. There were no differences on two types of visual errors. Subjects then received instruction in spelling for nine months in either morning or afternoon settings. Time-of-day effects were not evident on the word list and there were too few errors to conduct a posttest error analysis. However, standardized test results for a subgroup revealed that subjects receiving morning instruction made greater gains on phonetically regular words compared to phonetically irregular words--an effect consistent with a circadian-linked higher level of left hemisphere engagement early in the day. The findings are of a pilot nature, but implications for education and further research are discussed.

  19. Contralateral white noise selectively changes left human auditory cortex activity in a lexical decision task.

    Science.gov (United States)

    Behne, Nicole; Wendt, Beate; Scheich, Henning; Brechmann, André

    2006-04-01

    In a previous study, we hypothesized that the approach of presenting information-bearing stimuli to one ear and noise to the other ear may be a general strategy to determine hemispheric specialization in auditory cortex (AC). In that study, we confirmed the dominant role of the right AC in directional categorization of frequency modulations by showing that fMRI activation of right but not left AC was sharply emphasized when masking noise was presented to the contralateral ear. Here, we tested this hypothesis using a lexical decision task supposed to be mainly processed in the left hemisphere. Subjects had to distinguish between pseudowords and natural words presented monaurally to the left or right ear either with or without white noise to the other ear. According to our hypothesis, we expected a strong effect of contralateral noise on fMRI activity in left AC. For the control conditions without noise, we found that activation in both auditory cortices was stronger on contralateral than on ipsilateral word stimulation consistent with a more influential contralateral than ipsilateral auditory pathway. Additional presentation of contralateral noise did not significantly change activation in right AC, whereas it led to a significant increase of activation in left AC compared with the condition without noise. This is consistent with a left hemispheric specialization for lexical decisions. Thus our results support the hypothesis that activation by ipsilateral information-bearing stimuli is upregulated mainly in the hemisphere specialized for a given task when noise is presented to the more influential contralateral ear.

  20. Hemispheric asymmetries: The comparative view

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    Sebastian eOcklenburg

    2012-01-01

    Full Text Available Hemispheric asymmetries play an important role in almost all cognitive functions. For more than a century, they were considered to be uniquely human but now an increasing number of findings in all vertebrate classes make it likely that we inherited our asymmetries from common ancestors. Thus, studying animal models could provide unique insights into the mechanisms of lateralization. We outline three such avenues of research by providing an overview of experiments on left-right differences in the connectivity of sensory systems, the embryonic determinants of brain asymmetries, and the genetics of lateralization. All these lines of studies could provide a wealth of insights into our own asymmetries that should and will be exploited by future analyses.

  1. Hemispheric dominance and cell phone use.

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    Seidman, Michael D; Siegel, Bianca; Shah, Priyanka; Bowyer, Susan M

    2013-05-01

    A thorough understanding of why we hold a cell phone to a particular ear may be of importance when studying the impact of cell phone safety. To determine if there is an obvious association between sidedness of cell phone use and auditory hemispheric dominance (AHD) or language hemispheric dominance (LHD). It is known that 70% to 95% of the population are right-handed, and of these, 96% have left-brain LHD. We have observed that most people use their cell phones in their right ear. An Internet survey was e-mailed to individuals through surveymonkey.com. The survey used a modified Edinburgh Handedness Inventory protocol. Sample questions surveyed which hand was used to write with, whether the right or left ear was used for phone conversations, as well as whether a brain tumor was present. General community. An Internet survey was randomly e-mailed to 5000 individuals selected from an otology online group, patients undergoing Wada testing and functional magnetic resonance imaging, as well as persons on the university listserv, of which 717 surveys were completed. Determination of hemispheric dominance based on preferred ear for cell phone use. A total of 717 surveys were returned. Ninety percent of the respondents were right handed, and 9% were left handed. Sixty-eight percent of the right-handed people used the cell phone in their right ear, 25% in the left ear, and 7% had no preference. Seventy-two of the left-handed respondents used their left ear, 23% used their right ear, and 5% had no preference. Cell phone use averaged 540 minutes per month over the past 9 years. An association exists between hand dominance laterality of cell phone use (73%) and our ability to predict hemispheric dominance. Most right-handed people have left-brain LHD and use their cell phone in their right ear. Similarly, most left-handed people use their cell phone in their left ear. Our study suggests that AHD may differ from LHD owing to the difference in handedness and cell phone ear use

  2. Glutamate is down-regulated and tinnitus loudness-levels decreased following rTMS over auditory cortex of the left hemisphere: A prospective randomized single-blinded sham-controlled cross-over study.

    Science.gov (United States)

    Cacace, Anthony T; Hu, Jiani; Romero, Stephen; Xuan, Yang; Burkard, Robert F; Tyler, Richard S

    2017-11-14

    Using a prospective randomized single-blinded sham-controlled cross-over design, we studied the efficacy of low frequency (1-Hz) repetitive transcranial magnetic stimulation (rTMS) over auditory cortex of the left temporal lobe as an experimental treatment modality for noise-induced tinnitus. Pre/post outcome measures for sham vs. active rTMS conditions included differential changes in tinnitus loudness, self-perceived changes in the Tinnitus Handicap Questionnaire (THQ), and neurochemical changes of brain metabolite concentrations using single voxel proton magnetic resonance spectroscopy ( 1 H-MRS) obtained from left and right auditory cortical areas. While no subject in our sample had complete abatement of their tinnitus percept, active but not sham rTMS significantly reduced the loudness level of the tinnitus perception on the order of 4.5 dB; improved subscales in several content areas on the THQ, and down regulated (reduced) glutamate concentrations specific to the auditory cortex of the left temporal lobe that was stimulated. In addition, significant pair-wise correlations were observed among questionnaire variables, metabolite variables, questionnaire-metabolite variables, and metabolite-loudness variables. As part of this correlation analysis, we demonstrate for the first time that active rTMS produced a down regulation in the excitatory neurotransmitter glutamate that was highly correlated (r = 0.77, p < 0.05) with a reduction in tinnitus loudness levels measured psychoacoustically with a magnitude estimation procedure. Overall, this study provides unique information on neurochemical, psychoacoustic, and questionnaire-related profiles which emphasizes the emerging fields of perceptual and cognitive MRS and provides a perspective on a new frontier in auditory and tinnitus-related research. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity

    Science.gov (United States)

    Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

    2014-05-01

    Near-infrared spectroscopy (NIRS) is a developing and promising functional brain imaging technology. Developing data analysis methods to effectively extract meaningful information from collected data is the major bottleneck in popularizing this technology. In this study, we measured hemodynamic activity of the prefrontal cortex (PFC) during a color-word matching Stroop task using NIRS. Hemispheric lateralization was examined by employing traditional activation and novel NIRS-based connectivity analyses simultaneously. Wavelet transform coherence was used to assess intrahemispheric functional connectivity. Spearman correlation analysis was used to examine the relationship between behavioral performance and activation/functional connectivity, respectively. In agreement with activation analysis, functional connectivity analysis revealed leftward lateralization for the Stroop effect and correlation with behavioral performance. However, functional connectivity was more sensitive than activation for identifying hemispheric lateralization. Granger causality was used to evaluate the effective connectivity between hemispheres. The results showed increased information flow from the left to the right hemispheres for the incongruent versus the neutral task, indicating a leading role of the left PFC. This study demonstrates that the NIRS-based connectivity can reveal the functional architecture of the brain more comprehensively than traditional activation, helping to better utilize the advantages of NIRS.

  4. Hemispheric asymmetry for affective stimulus processing in healthy subjects--a fMRI study.

    Directory of Open Access Journals (Sweden)

    Esther Beraha

    Full Text Available BACKGROUND: While hemispheric specialization of language processing is well established, lateralization of emotion processing is still under debate. Several conflicting hypotheses have been proposed, including right hemisphere hypothesis, valence asymmetry hypothesis and region-specific lateralization hypothesis. However, experimental evidence for these hypotheses remains inconclusive, partly because direct comparisons between hemispheres are scarce. METHODS: The present fMRI study systematically investigated functional lateralization during affective stimulus processing in 36 healthy participants. We normalized our functional data on a symmetrical template to avoid confounding effects of anatomical asymmetries. Direct comparison of BOLD responses between hemispheres was accomplished taking two approaches: a hypothesis-driven region of interest analysis focusing on brain areas most frequently reported in earlier neuroimaging studies of emotion; and an exploratory whole volume analysis contrasting non-flipped with flipped functional data using paired t-test. RESULTS: The region of interest analysis revealed lateralization towards the left in the medial prefrontal cortex (BA 10 during positive stimulus processing; while negative stimulus processing was lateralized towards the right in the dorsolateral prefrontal cortex (BA 9 & 46 and towards the left in the amygdala and uncus. The whole brain analysis yielded similar results and, in addition, revealed lateralization towards the right in the premotor cortex (BA 6 and the temporo-occipital junction (BA 19 & 37 during positive stimulus processing; while negative stimulus processing showed lateralization towards the right in the temporo-parietal junction (BA 37,39,42 and towards the left in the middle temporal gyrus (BA 21. CONCLUSION: Our data suggests region-specific functional lateralization of emotion processing. Findings show valence asymmetry for prefrontal cortical areas and left

  5. Hemispheric asymmetry and theory of mind: is there an association?

    Science.gov (United States)

    Herzig, Daniela A; Sullivan, Sarah; Evans, Jonathan; Corcoran, Rhiannon; Mohr, Christine

    2012-01-01

    In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations. Healthy participants (n=129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only). The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of "overinterpreting" the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

  6. Ipsilesional deficit of selective attention in left homonymous hemianopia and left unilateral spatial neglect.

    Science.gov (United States)

    Chokron, Sylvie; Peyrin, Carole; Perez, Céline

    2018-03-15

    Patients with homonymous hemianopia may present a subtle ipsilesional deficit, recently referred to as 'sightblindness' in addition to the contralesional visual field defect. We recently demonstrated that this deficit could be worse in right brain-damaged patients with left hemianopia than in left brain-damaged patients with right hemianopia, confirming right hemisphere dominance for visuo-spatial and attentional capacities. In the present study we investigate whether this ipsilesional deficit could be attentional in nature and to what extent it is comparable in right brain-damaged (RBD) patients with left hemianopia and in RBD patients with left neglect. The study was also conducted in RBD patients with neither left hemianopia nor left neglect signs in order to test if a right hemisphere lesion per se could be responsible for subtle ipsilesional attentional deficit. To reach this aim, we tested selective attentional capacities in both visual fields of 10 right brain-damaged patients with left neglect (LN), 8 right brain-damaged patients with left homonymous hemianopia (LHH), 8 right brain-damaged patients with no signs of left neglect or left hemianopia (RBD controls), and 17 healthy age-matched participants (Normal controls). A lateralized letter-detection task was used to test if right-brain damaged patients with LN or LH may present a deficit of selective attention in their right, ipsilesional visual field, in comparison to Normal and RBD controls. Participants were asked to detect a target letter in either a single large stimulus (low attentional load) or a small stimulus surrounded by flankers (high attentional load). Stimuli were displayed either in the left or in the right visual field. Accuracy and reaction times were recorded. Results on accuracy showed that both LN and LH patients exhibited lower correct responses than Normal controls in their ipsilesional right visual field, suggesting an attentional deficit in their ipsilesional, supposed healthy

  7. Monocular learning of a spatial task enhances sleep in the right hemisphere of domestic chicks (Gallus gallus).

    Science.gov (United States)

    Nelini, Cristian; Bobbo, Daniela; Mascetti, Gian G

    2012-05-01

    Unihemispheric sleep is an aspect of cerebral lateralization of birds. During sleep, domestic chicks show brief periods during which one eye is open whilst the other remains shut. In this study, time spent in sleeping and in monocular-unihemispheric sleep (Mo-Un sleep) was investigated following the monocular learning of a spatial discrimination task. Two groups of experimental chicks from day 8 to day 11 post-hatching were trained in a spatial paradigm based on geometrical and topographical clues. One group performed the task with left eye open (LE-chicks), whilst another group performed the task with the right eye open (RE-chicks). LE-chick learned the task, whilst RE-chicks were unable to learn. Time spent in binocular sleep and right Mo-Un sleep (right eye closed and left hemisphere sleeping) was equal in both groups of chicks. Time spent in left Mo-Un sleep (left eye closed and right hemisphere sleeping) was significantly higher in LE-chicks than in RE-chicks. Laterality index reveals that LE-chicks had a significant bias towards more left Mo-Un sleep at any recording day, whilst RE-chicks showed a significant bias towards more right Mo-Un sleep at day 8 and 9 but not at days 10 and 11. RE-chick bias at days 8 and 9 could be attributed to a recovery process in left hemisphere connected to its activation/use effect during trials whilst recovery would be absent at days 10 and 11. LE-chicks bias would be associated with the formation of a spatial memory trace and with a recovery process in right hemisphere.

  8. Hemispheric asymmetry in the influence of language on visual perception.

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    Sun, Yanliang; Cai, Yongchun; Lu, Shena

    2015-07-01

    Many studies have shown that language can affect visual perception; however, our understanding of the neural basis of linguistic influence is inadequate. This can be investigated by examining the hemispheric asymmetry of linguistic influence. The left and right hemispheres are dominant in close and distant semantic processing, respectively. In this study, we investigated whether the hemispheric asymmetry of semantic processing led to hemispheric asymmetry for concept priming on the detection of objects degraded by continuous flash suppression. We combined a priming paradigm with the divided visual field paradigm and used continuous flash suppression, which renders objects invisible. The results indicated that the hemispheric asymmetry of semantic processing led to a right lateralization in the influence of more abstract concepts on visual perception. The lateralization of brain connectomes may be the underlying neural basis of this effect. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Selectivity of N170 for visual words in the right hemisphere: Evidence from single-trial analysis.

    Science.gov (United States)

    Yang, Hang; Zhao, Jing; Gaspar, Carl M; Chen, Wei; Tan, Yufei; Weng, Xuchu

    2017-08-01

    Neuroimaging and neuropsychological studies have identified the involvement of the right posterior region in the processing of visual words. Interestingly, in contrast, ERP studies of the N170 typically demonstrate selectivity for words more strikingly over the left hemisphere. Why is right hemisphere selectivity for words during the N170 epoch typically not observed, despite the clear involvement of this region in word processing? One possibility is that amplitude differences measured on averaged ERPs in previous studies may have been obscured by variation in peak latency across trials. This study examined this possibility by using single-trial analysis. Results show that words evoked greater single-trial N170s than control stimuli in the right hemisphere. Additionally, we observed larger trial-to-trial variability on N170 peak latency for words as compared to control stimuli over the right hemisphere. Results demonstrate that, in contrast to much of the prior literature, the N170 can be selective to words over the right hemisphere. This discrepancy is explained in terms of variability in trial-to-trial peak latency for responses to words over the right hemisphere. © 2017 Society for Psychophysiological Research.

  10. A Preliminary fMRI Study of a Novel Self-Paced Written Fluency Task: Observation of Left-Hemispheric Activation, and Increased Frontal Activation in Late vs. Early Task Phases

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    Laleh eGolestanirad

    2015-03-01

    Full Text Available Neuropsychological tests of verbal fluency are very widely used to characterize impaired cognitive function. For clinical neuroscience studies and potential medical applications, measuring the brain activity that underlies such tests with functional magnetic resonance imaging (fMRI is of significant interest - but a challenging proposition because overt speech can cause signal artifacts, which tend to worsen as the duration of speech tasks becomes longer. In a novel approach, we present the group brain activity of 12 subjects who performed a self-paced written version of phonemic fluency using fMRI-compatible tablet technology that recorded responses and provided task-related feedback on a projection screen display, over long-duration task blocks (60 s. As predicted, we observed robust activation in the left anterior inferior and medial frontal gyri, consisting with previously reported results of verbal fluency tasks which established the role of these areas in strategic word retrieval. In addition, the number of words produced in the late phase (last 30 s of written phonemic fluency was significantly less (p < 0.05 than the number produced in the early phase (first 30 s. Activation during the late phase vs. the early phase was also assessed from the first 20 s and last 20 s of task performance, which eliminated the possibility that the sluggish hemodynamic response from the early phase would affect the activation estimates of the late phase. The last 20 s produced greater activation maps covering extended areas in bilateral precuneus, cuneus, middle temporal gyrus, insula, middle frontal gyrus and cingulate gyrus. Among them, greater activation was observed in the bilateral middle frontal gyrus (Brodmann area BA 9 and cingulate gyrus (BA 24, 32 likely as part of the initiation, maintenance, and shifting of attentional resources.

  11. A preliminary fMRI study of a novel self-paced written fluency task: observation of left-hemispheric activation, and increased frontal activation in late vs. early task phases.

    Science.gov (United States)

    Golestanirad, Laleh; Das, Sunit; Schweizer, Tom A; Graham, Simon J

    2015-01-01

    Neuropsychological tests of verbal fluency are very widely used to characterize impaired cognitive function. For clinical neuroscience studies and potential medical applications, measuring the brain activity that underlies such tests with functional magnetic resonance imaging (fMRI) is of significant interest-but a challenging proposition because overt speech can cause signal artifacts, which tend to worsen as the duration of speech tasks becomes longer. In a novel approach, we present the group brain activity of 12 subjects who performed a self-paced written version of phonemic fluency using fMRI-compatible tablet technology that recorded responses and provided task-related feedback on a projection screen display, over long-duration task blocks (60 s). As predicted, we observed robust activation in the left anterior inferior and medial frontal gyri, consistent with previously reported results of verbal fluency tasks which established the role of these areas in strategic word retrieval. In addition, the number of words produced in the late phase (last 30 s) of written phonemic fluency was significantly less (p < 0.05) than the number produced in the early phase (first 30 s). Activation during the late phase vs. the early phase was also assessed from the first 20 s and last 20 s of task performance, which eliminated the possibility that the sluggish hemodynamic response from the early phase would affect the activation estimates of the late phase. The last 20 s produced greater activation maps covering extended areas in bilateral precuneus, cuneus, middle temporal gyrus, insula, middle frontal gyrus and cingulate gyrus. Among these areas, greater activation was observed in the bilateral middle frontal gyrus (Brodmann area BA 9) and cingulate gyrus (BA 24, 32) likely as part of the initiation, maintenance, and shifting of attentional resources. Consistent with previous pertinent fMRI literature involving overt and covert verbal responses, these findings highlight the

  12. Hemispheric specialization of abacus experts in mental calculation: evidence from the results of time-sharing tasks.

    Science.gov (United States)

    Hatta, T; Ikeda, K

    1988-01-01

    Hemispheric specialization for mental calculation and verbal tasks in abacus (Soroban in Japanese) experts and control subjects was tested using time-sharing tasks. In Experiment 1, the effects of auditorily presented mental calculation and news-listening tasks on sequential finger tappings were examined. The results revealed that in the mental calculation condition, abacus experts showed greater interference effects on left hand tapping, whereas control subjects showed greater interference effects on right hand tapping (as compared to left hand). In the news-listening condition, abacus experts showed no hand difference while the controls showed greater interference effects on the right hand. In Experiment 2, the effects of visually presented mental calculation and word-reading tasks on sequential finger tapping were examined. The results revealed that in the mental calculation condition, abacus experts showed a non-significant tendency towards greater interference in the left hand whereas the controls showed no hand difference. In the word-reading condition, both abacus experts and controls showed greater interference in the right hand than in the left hand. In Experiment 3, intermediate and upper-rank abacus experts performed a similar task to Experiment 1 under two instruction conditions. The results of this control experiment confirmed that a greater left hand reduction in calculation of abacus experts is not due to subject's cognitive mode but due to the amount of abacus learning experience. These data suggest that (1) learning experiences can affect the pattern of cerebral specialization through the change of approaches to perform cognitive tasks, and (2) the right hemisphere engages in mental calculation for the abacus experts whereas the left hemisphere contributes to mental calculation in ordinary people having no experience of abacus learning.

  13. Pharyngeal Swallowing Mechanics Secondary to Hemispheric Stroke.

    Science.gov (United States)

    May, Nelson H; Pisegna, Jessica M; Marchina, Sarah; Langmore, Susan E; Kumar, Sandeep; Pearson, William G

    2017-05-01

    Computational analysis of swallowing mechanics (CASM) is a method that utilizes multivariate shape change analysis to uncover covariant elements of pharyngeal swallowing mechanics associated with impairment using videofluoroscopic swallowing studies. The goals of this preliminary study were to (1) characterize swallowing mechanics underlying stroke-related dysphagia, (2) decipher the impact of left and right hemispheric strokes on pharyngeal swallowing mechanics, and (3) determine pharyngeal swallowing mechanics associated with penetration-aspiration status. Videofluoroscopic swallowing studies of 18 dysphagic patients with hemispheric infarcts and age- and gender-matched controls were selected from well-controlled data sets. Patient data including laterality and penetration-aspiration status were collected. Coordinates mapping muscle group action during swallowing were collected from videos. Multivariate morphometric analyses of coordinates associated with stroke, affected hemisphere, and penetration-aspiration status were performed. Pharyngeal swallowing mechanics differed significantly in the following comparisons: stroke versus controls (D = 2.19, P mechanics associated with each comparison were visualized using eigenvectors. Whereas current literature focuses on timing changes in stroke-related dysphagia, these data suggest that mechanical changes are also functionally important. Pharyngeal swallowing mechanics differed by the affected hemisphere and the penetration-aspiration status. CASM can be used to identify patient-specific swallowing impairment associated with stroke injury that could help guide rehabilitation strategies to improve swallowing outcomes. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  14. Bilinguals Have Different Hemispheric Lateralization in Visual Word Processing from Monolinguals

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    Sze-Man Lam

    2011-05-01

    Full Text Available Previous bilingual studies showed reduced hemispheric asymmetry in visual tasks such as face perception in bilinguals compared with monolinguals, suggesting experience in reading one or two languages could be a modulating factor. Here we examined whether difference in hemispheric asymmetry in visual tasks can also be observed in bilinguals who have different language backgrounds. We compared the behavior of three language groups in a tachistoscopic English word sequential matching task: English monolinguals (or alphabetic monolinguals, A-Ms, bilinguals with an alphabetic-L1 and English-L2 (alphabetic-alphabetic bilinguals, AA-Bs, and bilinguals with Chinese-L1 and English-L2 (logographic-alphabetic bilinguals, LA-Bs. The results showed that AA-Bs had a stronger right visual field/ left hemispheric (LH advantage than A-Ms and LA-Bs, suggesting that different language learning experiences can influence how visual words are processed in the brain. In addition, we showed that this effect could be accounted for by a computational model that implements a theory of hemispheric asymmetry in perception (i.e., the Double Filtering by Frequency theory; Ivry & Robertson, 1998; the modeling data suggested that this difference may be due to both the difference in participants' vocabulary size and the difference in word-to-sound mapping between alphabetic and logographic languages.

  15. From the Left to the Right: How the Brain Compensates Progressive Loss of Language Function

    Science.gov (United States)

    Thiel, Alexander; Habedank, Birgit; Herholz, Karl; Kessler, Josef; Winhuisen, Lutz; Haupt, Walter F.; Heiss, Wolf-Dieter

    2006-01-01

    In normal right-handed subjects language production usually is a function of the left brain hemisphere. Patients with aphasia following brain damage to the left hemisphere have a considerable potential to compensate for the loss of this function. Sometimes, but not always, areas of the right hemisphere which are homologous to language areas of the…

  16. The Impact of Left and Right Intracranial Tumors on Picture and Word Recognition Memory

    Science.gov (United States)

    Goldstein, Bram; Armstrong, Carol L.; Modestino, Edward; Ledakis, George; John, Cameron; Hunter, Jill V.

    2004-01-01

    This study investigated the effects of left and right intracranial tumors on picture and word recognition memory. We hypothesized that left hemispheric (LH) patients would exhibit greater word recognition memory impairment than right hemispheric (RH) patients, with no significant hemispheric group picture recognition memory differences. The LH…

  17. Motivation and motor control: hemispheric specialization for approach motivation reverses with handedness.

    Directory of Open Access Journals (Sweden)

    Geoffrey Brookshire

    Full Text Available BACKGROUND: According to decades of research on affective motivation in the human brain, approach motivational states are supported primarily by the left hemisphere and avoidance states by the right hemisphere. The underlying cause of this specialization, however, has remained unknown. Here we conducted a first test of the Sword and Shield Hypothesis (SSH, according to which the hemispheric laterality of affective motivation depends on the laterality of motor control for the dominant hand (i.e., the "sword hand," used preferentially to perform approach actions and the nondominant hand (i.e., the "shield hand," used preferentially to perform avoidance actions. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether the laterality of approach motivation varies with handedness, we measured alpha-band power (an inverse index of neural activity in right- and left-handers during resting-state electroencephalography and analyzed hemispheric alpha-power asymmetries as a function of the participants' trait approach motivational tendencies. Stronger approach motivation was associated with more left-hemisphere activity in right-handers, but with more right-hemisphere activity in left-handers. CONCLUSIONS: The hemispheric correlates of approach motivation reversed between right- and left-handers, consistent with the way they typically use their dominant and nondominant hands to perform approach and avoidance actions. In both right- and left-handers, approach motivation was lateralized to the same hemisphere that controls the dominant hand. This covariation between neural systems for action and emotion provides initial support for the SSH.

  18. Opposed hemispheric specializations for human hypersexuality and orgasm?

    Science.gov (United States)

    Suffren, Sabrina; Braun, Claude M J; Guimond, Anik; Devinsky, Orrin

    2011-05-01

    With a multiple case report analysis we demonstrate that hypersexuality more often results from right hemisphere (RH) (n=26) than left hemisphere (LH) (n=7) lesions, possibly because of LH release after the RH lesion, and that ictal orgasm more often occurs in patients with right-sided (n=23) than left-sided (n=8) seizure foci, with the symptom probably resulting from RH activation. The LH may be specialized for increasing sexual tension, whereas the RH may be specialized for release of this tension (orgasm), the former being catabolic and the latter anabolic. Several other interpretations of the findings are also discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Resting state EEG power, intra-hemisphere and inter-hemisphere coherence in bipolar disorder

    Science.gov (United States)

    Handayani, Nita; Khotimah, S. N.; Haryanto, F.; Arif, I.; Taruno, Warsito P.

    2017-02-01

    This paper examines the differences of EEG power and coherence between bipolar disorder patients and healthy subjects in the resting state. Observations are focused on the prefrontal cortex area by calculating intra-hemisphere and inter-hemisphere coherence. EEG data acquisition are conducted by using wireless Emotiv Epoc on AF3, AF4, FC5, FC6, F7 and F8 channels. The power spectral analysis shows that in bipolar disoder there is an increase of power in the delta, theta and beta frequencies, and power decrease in the alpha frequency. The coherence test results show that both intra-hemisphere and inter-hemisphere coherence in bipolar disorder patients are lower than healthy subjects. This shows the lack of brain synchronization in bipolar disorder patients.

  20. [Amusia and aphasia of Bolero's creator--influence of the right hemisphere on music].

    Science.gov (United States)

    Tudor, Lorraine; Sikirić, Predrag; Tudor, Katarina Ivana; Cambi-Sapunar, Liana; Radonić, Vedran; Tudor, Mario; Buca, Ante; Carija, Robert

    2008-07-01

    The experience with cortical localization (BA 44, 45, 22) of language (Broca, Wernicke and others) in the left hemisphere has been repeatedly tested over the last 150 years and is now generally accepted. A single case report with autopsy findings (Leborgne, Tan tan), has enabled to localize the seat of spoken language in the left third frontal convolution. As music and language have a lot in common and even share the same hearing system, it is logical to try to localize the cognitive centers for music too. The disabling neurological disease illness of Maurice Ravel (1875-1937), a French impressionist composer, is not the right example to localize music center as that of Broca's language center, but it demonstrates the role of the right hemisphere in music production. In the last five years of his life, Ravel suffered from an unknown disease that affected the left hemisphere causing aphasia, apraxia, alexia, agraphia and amusia. It was the reason why Ravel could not compose during the last years of his life. In contrast to Ravel, Shebalin and Britten continued writing music works of their own although aphasic after having sustained two strokes to the left hemisphere. While lacking clinical cases with selective ablative brain lesions, research into the music localization can be done using modern imaging technologies such as fMRI and PET. Exercising music (professionally) develops analytical process in the left hemisphere whereas other individuals process music in their right hemisphere. There is right ear (left hemisphere) predominance in musicians and vice versa in musical amateurs. Music lateralization towards the right hemisphere is seen in women and in inattentive listeners. It can be subject to cultural influence, so the Japanese process their traditional popular music in the left hemisphere, whereas Westerners process the same music in the right hemisphere. Music and language are processed separately; they are localized in homologous regions of the opposite

  1. EDUCATIONAL PECULIARITIES AND DIFFICULTIES OF CHILDREN WITH LEFT-SIDED LATERALITY: THE TECHNOLOGICAL SOLUTION OF THE PROBLEM

    Directory of Open Access Journals (Sweden)

    Maria Sitnikova

    2011-09-01

    Full Text Available Nowadays there is a significant increase of the incidence of left-handedness and sinistrality among schoolchildren. Theydemonstrate a large number of left-sided motor and sensory preferences which are considered as external markers offunctional hemispheric asymmetry of the brain. The purposes of this study are to investigate gender peculiarities and specificityof age-related dynamics of laterality pattern’s formation in junior schoolchildren and to find out educational peculiarities anddifficulties of left-handed children. The findings show that left-handers differ greatly in their mental development by havingsome peculiarities of intelligence, world’s perception and prevailing thinking strategies, ways of memorization, specificity ofemotional-affective expression. The main problems of left-handed children in school performance are academic failure, lack ofperseverance, anxiety neurosis, and extreme emotional lability. Integrated development of the left hemisphere and the righthemisphere thinking of left-handed schoolchildren is a favorable condition for harmonious personal and intellectualdevelopment and effective mastering of various modules of the school curriculum. The technological solution of the problem ofteaching the children with left-sided laterality is to include in educational programs some special exercises to developimagination, emotional sensitivity, integrity of perception, global view to the problems, creativeness, and original approachesto tasks’ solving. So a complex program for the intensive development of the right hemisphere of children who demonstrateleft-sided laterality to overcome the possible failure at primary school is proposed in this paper.

  2. The right hemisphere's contribution to discourse processing: A study in temporal lobe epilepsy.

    Science.gov (United States)

    Lomlomdjian, Carolina; Múnera, Claudia P; Low, Daniel M; Terpiluk, Verónica; Solís, Patricia; Abusamra, Valeria; Kochen, Silvia

    2017-08-01

    Discourse skills - in which the right hemisphere has an important role - enables verbal communication by selecting contextually relevant information and integrating it coherently to infer the correct meaning. However, language research in epilepsy has focused on single word analysis related mainly to left hemisphere processing. The purpose of this study was to investigate discourse abilities in patients with right lateralized medial temporal lobe epilepsy (RTLE) by comparing their performance to that of patients with left temporal lobe epilepsy (LTLE). 74 pharmacoresistant temporal lobe epilepsy (TLE) patients were evaluated: 34 with RTLE and 40 with LTLE. Subjects underwent a battery of tests that measure comprehension and production of conversational and narrative discourse. Disease related variables and general neuropsychological data were evaluated. The RTLE group presented deficits in interictal conversational and narrative discourse, with a disintegrated speech, lack of categorization and misinterpretation of social meaning. LTLE group, on the other hand, showed a tendency to lower performance in logical-temporal sequencing. RTLE patients showed discourse deficits which have been described in right hemisphere damaged patients due to other etiologies. Medial and anterior temporal lobe structures appear to link semantic, world knowledge, and social cognition associated areas to construct a contextually related coherent meaning. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Tomada de decisão no IGT: estudo de caso pós-AVC de hemisfério direito versus esquerdo Toma de decisión en el IGT: estudio de caso post-AVC de hemisferio derecho versus isquierdo Decision making in IGT: a case study of post-CVA of left versus right hemisphere

    Directory of Open Access Journals (Sweden)

    Caroline de Oliveira Cardoso

    2012-04-01

    decision-making process of two post-unilateral CVA adults as well as verifying the role of hemispheric laterality in the performance of Iowa Gambling Task (IGT. One adult with right hemisphere damage (RHD and another with left hemisphere damage (LHD, both following a subcortical ischemic post-CVA. The IGT was used to evaluate the decision making. Patients had appropriate performance on the IGT suggesting a general good ability to make decisions. However, only the patient with LHD presented signs of ascendant learning curve. Conclusion: These data indicate that a subcortical lesion independent of the hemisphere may not influence on the IGT performance. It is suggested that comparative studies of groups should be conducted in order to compare patients with frontal and non-frontal lesions, helping to characterize the decision-making process in population with unilateral vascular damage.

  4. Lateral thinkers are not so laterally minded: hemispheric asymmetry, interaction, and creativity.

    Science.gov (United States)

    Lindell, Annukka K

    2011-07-01

    The biological basis of creativity remains a topic of contention. A long-held view suggests that whereas the left hemisphere is intelligent and analytic, the right hemisphere is the source of all creativity. Consequently, activating the right hemisphere should enhance creative thinking, prompting a plethora of popular books hawking a right hemisphere solution to topics ranging from drawing, to money management, to sex. More recently, an alternate proposal has suggested that creativity is not a lateralised function; instead, creativity is argued to stem from the interaction and integration of information across both the left and right hemispheres. According to this view, individuals with greater interhemispheric communication and/or less-lateralised brains will evidence enhanced creative ability. This paper reviews the neural basis of creativity to determine whether creativity stems from activation of the right hemisphere, or from the interaction of both hemispheres. The relationship between creativity and psychopathology is also examined, evaluating the evidence for a causal link between disorders such as schizophrenia, hemispheric activation, and enhanced creativity. Although the research reviewed indicates greater right hemisphere activity during creative tasks, the interaction between many varied, often distant, cortical regions across both the left and right hemispheres is also a crucial component of creativity. This interaction facilitates the integration of a variety of separate cognitive abilities, fostering creative thinking. As such, creativity is better conceptualised as a distributed, rather than a purely lateralised, function; more lateral thinkers have less lateralised brains.

  5. Individual differences in hemispheric preference and emotion regulation difficulties

    Directory of Open Access Journals (Sweden)

    Garima Gupta

    2011-01-01

    Full Text Available Background: Hemisphericity or individual difference in the preference to use the left or the right hemispheric mode of information processing has been associated with various emotion-related differences. For example, the right hemisphericity has been linked with inhibition of emotional expression, feeling of tension, greater impulsivity etc. These observations suggest that right hemisphericity may be associated with greater difficulties in regulating emotions. However, direct empirical tests of such theoretical proposition are very thin. Aim: In view of this, the present study aims to investigate how and to what extent individual difference in hemispheric preference relate to emotion regulation. Materials and Methods: Thirty-two right-handed male subjects in the age range 18 to 20 years were assessed on self-report measures of hemispheric preference and emotion regulation difficulties. The correlation between dimensions of hemispheric preference and difficulties in regulating emotions was computed. A series of stepwise multiple regression analyses were also done to explore the relative significance of various dimensions of hemispheric preference in predicting emotion regulation difficulties. Results: The findings revealed that in general a preference for the right hemispheric mode of information processing was associated with greater emotion regulation difficulties. The correlation analysis indicated that while impulse control difficulties and difficulties in engaging goal directed behavior was associated with preference for almost all the right hemispheric mode of information processing, the nonacceptance of emotional responses and limited access to emotion regulation was related to preference for only global/synthetic (a right hemispheric mode of information processing. Similarly, the lack of emotional clarity facet of emotion regulation difficulties correlated significantly with a preference for the emotional mode of information processing

  6. Quantitative and qualitative hemispheric asymmetry for processing Japanese kana.

    Science.gov (United States)

    Hellige, J B; Yamauchi, M

    1999-08-01

    Native Japanese speakers identified three-letter kana stimuli presented to the left visual field and right hemisphere (LVF/RH), to the right visual field and left hemisphere (RVF/LH), or to both visual fields and hemispheres simultaneously (BILATERAL trials). There were fewer errors on RVF/LH and BILATERAL trials than on LVF/RH trials. Qualitative analysis of error patterns indicated that there were many fewer errors of first-letter identification than of last-letter identification, suggesting top-to-bottom scanning of the kana characters. In contrast to similar studies presenting nonword letter trigrams to native English speakers, qualitative error patterns were identical for the three visual field conditions. Taken together with the results of earlier studies, the results of the present experiment indicate that the ubiquitous RVF/LH advantage reflects a left-hemisphere superiority for phonetic processing that generalizes across specific languages. At the same time, qualitative aspects of hemispheric asymmetry differ from one language to the next and may depend on such things as the way in which individual characters map onto the pronunciation of words and nonwords. Copyright 1999 Academic Press.

  7. Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions

    DEFF Research Database (Denmark)

    Ward, Nick S; Bestmann, Sven; Hartwigsen, Gesa

    2010-01-01

    Left rostral dorsal premotor cortex (rPMd) and supramarginal gyrus (SMG) have been implicated in the dynamic control of actions. In 12 right-handed healthy individuals, we applied 30 min of low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) over left rPMd to investigate...... the involvement of left rPMd and SMG in the rapid adjustment of actions guided by visuospatial cues. After rTMS, subjects underwent functional magnetic resonance imaging while making spatially congruent button presses with the right or left index finger in response to a left- or right-sided target. Subjects were...... responses in invalidly cued trials. After real rTMS, task-related activity of the stimulated left rPMd showed increased task-related coupling with activity in ipsilateral SMG and the adjacent anterior intraparietal area (AIP). Individuals who showed a stronger increase in left-hemispheric premotor...

  8. Reversible hemispheric hypoperfusion in two cases of SMART syndrome.

    Science.gov (United States)

    Wai, Karmen; Balabanski, Anna; Chia, Nicholas; Kleinig, Timothy

    2017-09-01

    Stroke-like migraine attacks after radiation therapy (SMART) syndrome manifests as prolonged episodes of cortical dysfunction, years after cranial irradiation. We present two cases demonstrating reversible hemispheric hypoperfusion. Case 1 presented with left hemispheric symptoms following previous similar episodes. CT perfusion (CTP) demonstrated reversible hemispheric hypoperfusion; subsequent investigations were consistent with SMART syndrome. Case 2 presented following the third episode of a hemispheric syndrome with near-identical CTP abnormalities. L-arginine was administered with rapid reversal of clinical and CTP abnormalities. We conclude that SMART syndrome may demonstrate significant hypoperfusion on hyperacute CTP without subsequent infarction. Impaired cerebrovascular autoregulation probably contributes to cortical dysfunction in SMART syndrome. L-arginine warrants investigation as a potential treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A functional MRI study of language networks in left medial temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Yu Aihong; Wang Xiaoyi; Xu Guoqing; Li Yongjie; Qin Wen; Li Kuncheng; Wang, Yuping

    2011-01-01

    Purpose: The purpose of this study was to investigate the abnormality of language networks in left medial temporal lobe epilepsy (MTLE) using fMRI. Materials and methods: Eight patients with left MTLE and 15 healthy subjects were evaluated. An auditory semantic judgment (AJ) paradigm was used. The fMRI data were collected on a 3T MR system and analyzed by AFNI (analysis of functional neuroimages) to generate the activation map. Results: Behavioral data showed that the reaction time of the left MTLE patients was significantly longer than that of controls on the AJ task (t = -3.396, P < 0.05). The left MTLE patients also exhibited diffusively decreased activation in the AJ task. Right hemisphere dominance of Broca's and Wernicke's areas was demonstrated in left MTLE patients. Conclusions: Long-term activation of spikes in left MTLE patients results in language impairment, which is associated with an abnormality of the brain neural network.

  10. Split Fovea Theory and the Role of the Two Cerebral Hemispheres in Reading: A Review of the Evidence

    Science.gov (United States)

    Ellis, Andrew W.; Brysbaert, Marc

    2010-01-01

    Split fovea theory proposes that when the eyes are fixated within a written word, visual information about the letters falling to the left of fixation is projected initially to the right cerebral hemisphere while visual information about the letters falling to the right of fixation is projected to the left cerebral hemisphere. The two parts of the…

  11. Psychophysiological correlates of dissociation, handedness, and hemispheric lateralization.

    Science.gov (United States)

    Ashworth, Joel; Ciorciari, Joseph; Stough, Con

    2008-05-01

    Dissociation involves a disruption of typically integrated functions including consciousness, information perception, and memory; however, dissociation may not always be of a pathologic nature. Increasingly, studies are identifying relations between inconsistent handedness, mixed hemispheric lateralization, and dissociative symptomatology in both clinical and nonclinical populations. The current study explored whether a nonclinical sample of individuals scoring high in dissociation would display an inconsistent handedness in conjunction with a left hemispheric lateralization as measured by electroencephalography. Twenty-seven participants (12 males and 15 females) aged between 20 and 59 years (M = 29.1 year, SD = 11.2 years), completed the Dissociative Experiences Scale and Waterloo Handedness Questionnaire Revised after determining laterality. As predicted, inconsistently handed participants scoring high in dissociation displayed left hemispheric lateralization across frontal, central, and parietal regions. Conversely, right lateralization was found within Delta frequency band across temporal regions. The study provides a good framework for future research investigating the neurophysiological correlates underpinning dissociative symptomatology.

  12. Emotions and hemispheric specialization.

    Science.gov (United States)

    Kyle, N L

    1988-09-01

    Studies of lateralization and specialization of brain function have increased our understanding of emotional processes in the brain. It has been said that the way in which we understand the emotional interrelatedness of brain layers and segments may have important effects on human society. Earlier studies of brain function, especially of limbic effects, suggested a dichotomous state of affairs between the phylogenetically older brain and the newer cortical areas--between affect and cognition. Such concepts are considered here in the light of specialization studies. From the beginning hemispheric laterality research has implicated emotionality and emotional pathology. It also appears that some limbic functions may be mediated in a lateralized fashion. Neuropsychologists have directed much work toward localization of function from its earliest stage; since the 1960s an emphasis has been on "mapping" of cortical functions in terms of psychopathologic disabilities. Various disability groups have been studied in this way, and it may be concluded that neuropsychologic measures are sensitive to changes in cerebral functioning and may have effective lateralizing and localizing ability under specified conditions. Studies of limbic effects in the brain emphasize their importance in emotional behavior but also their interrelatedness with other structures, for example, the frontal and temporal lobes, and particularly the right hemisphere. Studies of commissurotomy (split-brain) patients tend to bear out these relationships. In split-brain subjects the marked reduction in affective verbal and nonverbal behavior reflects the interruption of transcallosal impulses that normally permit emotional infusion of cortical structures to take place. These effects include verbal, visual, and auditory patterns that mediate the ability to decode complex nonverbal patterns and may result in a reduction of "inner speech," that is, symbollexia. They may further lead to a condition of

  13. Migration of Sparganum of the Frontal Lobe to the Ipsilateral Cerebellar Hemisphere: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Eun A; Choi, See Sung; Jeon, Se Jeong; Kim, Hey Won; Lee, Young Hwan [Wonkwang University Hopital, Iksan (Korea, Republic of)

    2009-05-15

    Most cerebral sparganosis lesions are located in the white matter of the cerebral hemisphere. A few cases of cerebral sparganosis where the sparganum have migrated into the contralateral cerebral hemisphere have been reported. We report a case of cerebral sparganosis where the sparganum migrated from the white matter of the left frontal lobe to the ipsilateral cerebellar hemisphere after failure of surgical removal of the worm

  14. Are there excitability changes in the hand motor cortex during speech in left-handed subjects?

    Science.gov (United States)

    Tokimura, Hiroshi; Tokimura, Yoshika; Arita, Kazunori

    2012-01-01

    Hemispheric dominance was investigated in left-handed subjects using single transcranial magnetic stimulation to assess the possible effect of forced change in the dominant hand. Single transcranial magnetic stimuli were delivered randomly over the hand area of the left or right motor cortex of 8 Japanese self-declared left-handed adult volunteers. Electromyographic responses were recorded in the relaxed first dorsal interosseous muscle while the subjects read aloud. Laterality quotient calculated by the Edinburgh Inventory ranged from -100 to -5.26 and laterality index calculated from motor evoked potentials ranged from -86.2 to 38.8. There was no significant correlation between laterality quotient and laterality index. Mean data values across all 8 subjects indicated significant increases only in the left hand. Our ratio analysis of facilitation of the hand motor potentials showed that 2 each of the 8 self-declared left-handers were right- and left-hand dominant and the other 4 were bilateral-hand dominant. Speech dominancy was localized primarily in the right cerebral hemisphere in left-handed subjects, but some individuals exhibited bilateral or left dominance, possibly attributable to the forced change of hand preference for writing in childhood. Our findings suggest changes in the connections between the speech and hand motor areas.

  15. Hemispheric Lateralization of Verbal and Spatial Working Memory during Adolescence

    Science.gov (United States)

    Nagel, Bonnie J.; Herting, Megan M.; Maxwell, Emily C.; Bruno, Richard; Fair, Damien

    2013-01-01

    Adult functional magnetic resonance imaging (fMRI) literature suggests that a left-right hemispheric dissociation may exist between verbal and spatial working memory (WM), respectively. However, investigation of this type has been obscured by incomparable verbal and spatial WM tasks and/or visual inspection at arbitrary thresholds as means to…

  16. Callosal microstructure affects the timing of electrophysiological left-right differences.

    Science.gov (United States)

    Friedrich, Patrick; Ocklenburg, Sebastian; Heins, Nina; Schlüter, Caroline; Fraenz, Christoph; Beste, Christian; Güntürkün, Onur; Genç, Erhan

    2017-12-01

    The neural architecture of the corpus callosum shows pronounced inter-individual differences. These differences are thought to affect timing of interhemispheric interactions and, in turn, functional hemispheric asymmetries. The present study aimed at elucidating the neuronal mechanisms underlying this relationship. To this end, we used a combined DTI and EEG study design. In 103 right-handed and healthy adult participants, we determined the microstructural integrity of the posterior third of the corpus callosum and examined in how far this microstructural integrity was related to between-hemisphere timing differences in neurophysiological correlates of attentional processes in the dichotic listening task. The results show that microstructural integrity of the posterior callosal third correlated with attentional timing differences in a verbal dichotic listening condition but not in a noise control condition. Hence, this association between callosal microstructure and between-hemisphere timing differences is specific for stimuli, which trigger hemispheric bottom-up processing in an asymmetric fashion. Specifically, higher microstructural integrity was associated with decreased left-right differences in the latency of the N1 event-related potential component and hence more symmetric processing of dichotic stimuli between the two hemispheres. Our data suggest that microstructure of the posterior callosal third affects functional hemispheric asymmetries by modulating the timing of interhemispheric interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Black-White IQ Discrepancies May Be Related to Differences in Hemisphericity.

    Science.gov (United States)

    Reynolds, Cecil R.; And Others

    1981-01-01

    Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and McCarthy Scales subtests were ranked according to relative reliance on left-cerebral-hemisphere function. Results suggest that black-white IQ discrepancies may be partially explained by differences in hemisphericity. (Author/RD)

  18. Hemispheric Asymmetries in Semantic Processing: Evidence from False Memories for Ambiguous Words

    Science.gov (United States)

    Faust, Miriam; Ben-Artzi, Elisheva; Harel, Itay

    2008-01-01

    Previous research suggests that the left hemisphere (LH) focuses on strongly related word meanings; the right hemisphere (RH) may contribute uniquely to the processing of lexical ambiguity by activating and maintaining a wide range of meanings, including subordinate meanings. The present study used the word-lists false memory paradigm [Roediger,…

  19. Hemispheric Specialization and Creative Thinking: A Meta-Analytic Review of Lateralization of Creativity

    Science.gov (United States)

    Mihov, Konstantin M.; Denzler, Markus; Forster, Jens

    2010-01-01

    In the last two decades research on the neurophysiological processes of creativity has found contradicting results. Whereas most research suggests right hemisphere dominance in creative thinking, left-hemisphere dominance has also been reported. The present research is a meta-analytic review of the literature to establish how creative thinking…

  20. Increasing Northern Hemisphere water deficit

    Science.gov (United States)

    McCabe, Gregory J.; Wolock, David M.

    2015-01-01

    A monthly water-balance model is used with CRUTS3.1 gridded monthly precipitation and potential evapotranspiration (PET) data to examine changes in global water deficit (PET minus actual evapotranspiration) for the Northern Hemisphere (NH) for the years 1905 through 2009. Results show that NH deficit increased dramatically near the year 2000 during both the cool (October through March) and warm (April through September) seasons. The increase in water deficit near 2000 coincides with a substantial increase in NH temperature and PET. The most pronounced increases in deficit occurred for the latitudinal band from 0 to 40°N. These results indicate that global warming has increased the water deficit in the NH and that the increase since 2000 is unprecedented for the 1905 through 2009 period. Additionally, coincident with the increase in deficit near 2000, mean NH runoff also increased due to increases in P. We explain the apparent contradiction of concurrent increases in deficit and increases in runoff.

  1. Reliability of a novel paradigm for determining hemispheric lateralization of visuospatial function

    NARCIS (Netherlands)

    Whitehouse, A.J.O.; Badcock, N.A.; Groen, M.A.; Bishop, D.V.M.

    2009-01-01

    In most individuals, language production and visuospatial skills are subserved predominantly by the left and right hemispheres, respectively. Functional Transcranial Doppler (fTCD) provides a noninvasive and relatively low-cost method for measuring functional lateralization. However, while the

  2. Imaging network level language recovery after left PCA stroke.

    Science.gov (United States)

    Sebastian, Rajani; Long, Charltien; Purcell, Jeremy J; Faria, Andreia V; Lindquist, Martin; Jarso, Samson; Race, David; Davis, Cameron; Posner, Joseph; Wright, Amy; Hillis, Argye E

    2016-05-11

    The neural mechanisms that support aphasia recovery are not yet fully understood. Our goal was to evaluate longitudinal changes in naming recovery in participants with posterior cerebral artery (PCA) stroke using a case-by-case analysis. Using task based and resting state functional magnetic resonance imaging (fMRI) and detailed language testing, we longitudinally studied the recovery of the naming network in four participants with PCA stroke with naming deficits at the acute (0 week), sub acute (3-5 weeks), and chronic time point (5-7 months) post stroke. Behavioral and imaging analyses (task related and resting state functional connectivity) were carried out to elucidate longitudinal changes in naming recovery. Behavioral and imaging analysis revealed that an improvement in naming accuracy from the acute to the chronic stage was reflected by increased connectivity within and between left and right hemisphere "language" regions. One participant who had persistent moderate naming deficit showed weak and decreasing connectivity longitudinally within and between left and right hemisphere language regions. These findings emphasize a network view of aphasia recovery, and show that the degree of inter- and intra- hemispheric balance between the language-specific regions is necessary for optimal recovery of naming, at least in participants with PCA stroke.

  3. False memories to emotional stimuli are not equally affected in right- and left-brain-damaged stroke patients.

    Science.gov (United States)

    Buratto, Luciano Grüdtner; Zimmermann, Nicolle; Ferré, Perrine; Joanette, Yves; Fonseca, Rochele Paz; Stein, Lilian Milnitsky

    2014-10-01

    Previous research has attributed to the right hemisphere (RH) a key role in eliciting false memories to visual emotional stimuli. These results have been explained in terms of two right-hemisphere properties: (i) that emotional stimuli are preferentially processed in the RH and (ii) that visual stimuli are represented more coarsely in the RH. According to this account, false emotional memories are preferentially produced in the RH because emotional stimuli are both more strongly and more diffusely activated during encoding, leaving a memory trace that can be erroneously reactivated by similar but unstudied emotional items at test. If this right-hemisphere hypothesis is correct, then RH damage should result in a reduction in false memories to emotional stimuli relative to left-hemisphere lesions. To investigate this possibility, groups of right-brain-damaged (RBD, N=15), left-brain-damaged (LBD, N=15) and healthy (HC, N=30) participants took part in a recognition memory experiment with emotional (negative and positive) and non-emotional pictures. False memories were operationalized as incorrect responses to unstudied pictures that were similar to studied ones. Both RBD and LBD participants showed similar reductions in false memories for negative pictures relative to controls. For positive pictures, however, false memories were reduced only in RBD patients. The results provide only partial support for the right-hemisphere hypothesis and suggest that inter-hemispheric cooperation models may be necessary to fully account for false emotional memories. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Hemispheric biases and the control of visuospatial attention: an ERP study

    Directory of Open Access Journals (Sweden)

    Banich Marie T

    2005-08-01

    Full Text Available Abstract Background We examined whether individual differences in hemispheric utilization can interact with the intrinsic attentional biases of the cerebral hemispheres. Evidence suggests that the hemispheres have competing biases to direct attention contralaterally, with the left hemisphere (LH having a stronger bias than the right hemisphere. There is also evidence that individuals have characteristic biases to utilize one hemisphere more than the other for processing information, which can induce a bias to direct attention to contralateral space. We predicted that LH-biased individuals would display a strong rightward attentional bias, which would create difficulty in selectively attending to target stimuli in the left visual field (LVF as compared to right in the performance of a bilateral flanker task. Results Consistent with our hypothesis, flanker interference effects were found on the N2c event-related brain potential and error rate for LH-biased individuals in the Attend-LVF condition. The error rate effect was correlated with the degree of hemispheric utilization bias for the LH-Bias group. Conclusion We conclude that hemispheric utilization bias can enhance a hemisphere's contralateral attentional bias, at least for individuals with a LH utilization bias. Hemispheric utilization bias may play an important and largely unrecognized role in visuospatial attention.

  5. Right hemispatial ipsilesional neglect with chronic right hemisphere strokes.

    Science.gov (United States)

    Williamson, John B; Lamb, Damon G; Burtis, D Brandon; Haque, Salsabil; M Zilli, Eduardo; Kesayan, Tigran; Harciarek, Michal; Heilman, Kenneth M

    2018-05-01

    Patients who present with spatial neglect after stroke often perform normally on tests for neglect after a few weeks. Whereas tests for neglect are often performed directly in front of a patient, in their actual environments many important stimuli may be present within their left or right hemispace. The presence and severity of neglect often depends on the hemisphere injured. It is possible, in chronic stroke, for spatial judgments to be influenced by an interaction of stroke laterality and the spatial location of stimuli. The objective of this study was to learn if unilateral hemispheric chronic strokes contribute to a spatial bias with laterally presented stimuli. There were 70 participants, 62 with unilateral chronic strokes (>6 months post onset) including 35 with left hemisphere damage (LHD), 27 with right hemisphere damage (RHD), and 8 demographically similar people without history of stroke. Participants were asked to bisect 300 lines presented with distractors on the left, right, or both sides of the line, or no distractor, on a touch-screen monitor in right, center or left hemispace. There was a significant interaction between the side of the hemispheric lesion and the side of the body where these lines were presented. Specifically, in right space, patients with RHD deviated leftward in comparison to the other groups. Furthermore, there was an interaction between group and distractor induced bias. All three groups approached the left distractor, and the patients with LHD also approached the right distractor. Although spatial neglect is more severe in contralesional than ipsilesional hemispace in the period immediately following a stroke, over time patients with RHD may develop ipsilesional neglect that is more severe in ipsilesional than contralesional space. The mechanism underlying this bias is not known and may be related to attempted compensation or the development of a contralateral attentional/intentional grasp.

  6. Atypical right hemisphere specialization for object representations in an adolescent with specific language impairment

    Directory of Open Access Journals (Sweden)

    Timothy T. Brown

    2014-02-01

    Full Text Available Individuals with a diagnosis of specific language impairment (SLI show abnormal spoken language occurring alongside normal nonverbal abilities. Behaviorally, people with SLI exhibit diverse profiles of impairment involving phonological, grammatical, syntactic, and semantic aspects of language. In this study, we used a multimodal neuroimaging technique called anatomically constrained magnetoencephalography (aMEG to measure the dynamic functional brain organization of an adolescent with SLI. Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects. Localized, real-time patterns of brain activity within the language impaired patient showed marked differences from the typical functional organization, with significant engagement of right hemisphere heteromodal cortical regions generally homotopic to the left hemisphere areas that usually show the greatest activity for such tasks. Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations. Our findings show with real-time temporal specificity evidence for an atypical right hemisphere specialization for the representation of concrete entities, independent of verbal motor demands. More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

  7. Right cerebral hemisphere specialization for quiet and perturbed body balance control: Evidence from unilateral stroke.

    Science.gov (United States)

    Fernandes, Corina Aparecida; Coelho, Daniel Boari; Martinelli, Alessandra Rezende; Teixeira, Luis Augusto

    2018-02-01

    Our aim in this investigation was to assess the relative importance of each cerebral hemisphere in quiet and perturbed balance, based on uni-hemispheric lesions by stroke. We tested the hypothesis of right cerebral hemisphere specialization for balance control. Groups of damage either to the right (RHD, n=9) or the left (LHD, n=7) cerebral hemisphere were compared across tasks requiring quiet balance or body balance recovery following a mechanical perturbation, comparing them to age-matched nondisabled individuals (controls, n=24). They were evaluated in conditions of full and occluded vision. In Experiment 1, the groups were compared in the task of quiet standing on (A) rigid and (B) malleable surfaces, having as outcome measures center of pressure (CoP) amplitude and velocity sway. In Experiment 2, we evaluated the recovery of body balance following a perturbation inducing forward body oscillation, having as outcome measures CoP displacement, peak hip and ankle rotations and muscular activation of both legs. Results from Experiment 1 showed higher values of CoP sway velocity for RHD in comparison to LHD and controls in the anteroposterior (rigid surface) and mediolateral (malleable surface) directions, while LHD had lower balance stability than the controls only in the mediolateral direction when supported on the rigid surface. In Experiment 2 results showed that RHD led to increased values in comparison to LHD and controls for anteroposterior CoP displacement and velocity, time to CoP direction reversion, hip rotation, and magnitude of muscular activation in the paretic leg, while LHD was found to differ in comparison to controls in magnitude of muscular activation of the paretic leg and amplitude of mediolateral sway only. These results suggest that damage to the right as compared to the left cerebral hemisphere by stroke leads to poorer postural responses both in quiet and perturbed balance. That effect was not altered by manipulation of sensory information

  8. Volumetric hemispheric ratio as a useful tool in personality psychology.

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    Montag, Christian; Schoene-Bake, Jan-Christoph; Wagner, Jan; Reuter, Martin; Markett, Sebastian; Weber, Bernd; Quesada, Carlos M

    2013-02-01

    The present study investigates the link between volumetric hemispheric ratios (VHRs) and personality measures in N=267 healthy participants using Eysenck's Personality Inventory-Revised (EPQ-R) and the BIS/BAS scales. A robust association between extraversion and VHRs was observed for gray matter in males but not females. Higher gray matter volume in the left than in the right hemisphere was associated with higher extraversion in males. The results are discussed in the context of positive emotionality and laterality of the human brain. Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  9. Contralesional arm preference depends on hemisphere of damage and target location in unilateral stroke patients

    Science.gov (United States)

    Mani, Saandeep; Przybyla, Andrzej; Good, David C.; Haaland, Kathleen Y.; Sainburg, Robert L.

    2014-01-01

    Background Previous research has shown that during simulated activities of daily living right handed stroke patients use their contralesional arm more after left than right hemisphere stroke. These findings were attributed to a hand preference effect. However, these decisions about when to use the contralesional arm may be modulated by where in the work space the task is performed, a factor that could be used in physical rehabilitation to influence recovery by decreasing learned non-use. Objective To examine how target location and side of stroke influences arm selection choices for simple reaching movements. Methods Fourteen right-handed stroke patients (7 with left hemisphere damage, 7 with right hemisphere damage) with similar degree of hemiparesis (Fugl-Meyer motor score), and 16 right-handed control subjects participated in this experiment. Thirty-two targets were presented throughout the reachable horizontal plane workspace in a pseudo-random fashion, and the subjects were asked to select one hand to reach the target on each trial. Results The left hemisphere damaged group chose their contralesional arm significantly more often than the right hemisphere damaged group. Patients with right hemisphere damage also chose their left (contralesional) arm significantly less than the control group. However, these patterns of choice were most pronounced in the center of the workspace. Conclusion Both the side of hemisphere damage and workspace location played a significant role in the choice of whether to use the contralesional arm for reaching. These findings have implications for structuring rehabilitation for unilateral stroke patients. PMID:24523143

  10. Side biases in humans ( Homo sapiens): three ecological studies on hemispheric asymmetries

    Science.gov (United States)

    Marzoli, Daniele; Tommasi, Luca

    2009-09-01

    Hemispheric asymmetries and side biases have been studied in humans mostly in laboratory settings, and evidence obtained in naturalistic settings is scarce. We here report the results of three studies on human ear preference observed during social interactions in noisy environments, i.e., discotheques. In the first study, a spontaneous right-ear preference was observed during linguistic exchange between interacting individuals. This lateral bias was confirmed in a quasi-experimental study in which a confederate experimenter evoked an ear-orienting response in bystanders, under the pretext of approaching them with a whispered request. In the last study, subjects showed a greater proneness to meet an experimenter’s request when it was directly addressed to the right rather than the left ear. Our findings are in agreement both with laboratory studies on hemispheric lateralization for language and approach/avoidance behavior in humans and with animal research. The present work is one of the few studies demonstrating the natural expression of hemispheric asymmetries, showing their effect in everyday human behavior.

  11. Holistic Processing and Right Hemisphere Lateralization Do Not Always Go Together—Evidence from Computational Modeling

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    Janet H. Hsiao

    2011-05-01

    Full Text Available Studies on face recognition have suggested a relationship between holistic processing and right hemisphere (RH lateralization. Thus, it has long been assumed that holistic processing is a property of RH processing. Nevertheless, recent studies showed reduced holistic processing and increased RH lateralization in Chinese character recognition expertise, suggesting that these two effects may be separate processes. Through computational modeling, in which we implement a theory of hemispheric asymmetry in perception that posits a low spatial frequency bias in the RH and a high spatial frequency bias in the left hemisphere (i.e. the Double Filtering by Frequency Theory, Ivry & Robertson, 1998, here we show that when the recognition task relies purely on featural information, holistic processing increases whereas RH lateralization decreases with increasing stimulus similarity, and there is a negative correlation between them. In contrast, when the recognition task relies purely on configural information, although holistic processing also increases whereas RH lateralization decreases with increasing stimulus similarity, there is no correlation between them. This result suggests that holistic processing and RH lateralization are separate processes that can be influenced differentially by task requirements.

  12. Hemispheric speech lateralisation in the developing brain is related to motor praxis ability.

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    Hodgson, Jessica C; Hirst, Rebecca J; Hudson, John M

    2016-12-01

    Commonly displayed functional asymmetries such as hand dominance and hemispheric speech lateralisation are well researched in adults. However there is debate about when such functions become lateralised in the typically developing brain. This study examined whether patterns of speech laterality and hand dominance were related and whether they varied with age in typically developing children. 148 children aged 3-10 years performed an electronic pegboard task to determine hand dominance; a subset of 38 of these children also underwent functional Transcranial Doppler (fTCD) imaging to derive a lateralisation index (LI) for hemispheric activation during speech production using an animation description paradigm. There was no main effect of age in the speech laterality scores, however, younger children showed a greater difference in performance between their hands on the motor task. Furthermore, this between-hand performance difference significantly interacted with direction of speech laterality, with a smaller between-hand difference relating to increased left hemisphere activation. This data shows that both handedness and speech lateralisation appear relatively determined by age 3, but that atypical cerebral lateralisation is linked to greater performance differences in hand skill, irrespective of age. Results are discussed in terms of the common neural systems underpinning handedness and speech lateralisation. Copyright © 2016. Published by Elsevier Ltd.

  13. Functional MRI approach for assessing hemispheric predominance of regions activated by a phonological and a semantic task

    International Nuclear Information System (INIS)

    Cousin, Emilie; Peyrin, Carole; Pichat, Cedric; Lamalle, Laurent; Le Bas, Jean-Francois; Baciu, Monica

    2007-01-01

    This fMRI study performed in healthy subjects aimed at using a statistical approach in order to determine significant functional differences between hemispheres and to assess specialized regions activated during a phonological and during a semantic task. This approach ('flip' method and subsequent statistical analyses of the parameter estimates extracted from regions of interest) allows identifying: (a) hemispheric specialized regions for each language task [semantic (living categorization) and phonological (rhyme detection)] and (b) condition-specific regions with respect to paradigm conditions (task and control). Our results showed that the rhyme-specific task regions were the inferior frontal (sub-region of BA 44, 45) and left inferior parietal (BA 40, 39) lobules. Furthermore, within the inferior parietal lobule, the angular gyrus was specific to target (rhyming) items (related to successfully grapho-phonemic processing). The categorization-specific task regions were the left inferior frontal (sub-region of BA 44, 45) and superior temporal (BA 22) cortices. Furthermore, the superior temporal gyrus was related to non-target (non-living) items (correlated to task difficulty). The relatively new approach used in this study has the advantage of providing: (a) statistical significance of the hemispheric specialized regions for a given language task and (b) supplementary information in terms of paradigm condition-specificity of the activated regions. The results (standard hemispheric specialized regions for a semantic and for a phonological task) obtained in healthy subjects may constitute a basement for mapping language and assessing hemispheric predominance in epileptic patients before surgery and avoiding post-surgical impairments of language

  14. Mapping number to space in the two hemispheres of the avian brain.

    Science.gov (United States)

    Rugani, Rosa; Vallortigara, Giorgio; Regolin, Lucia

    2016-09-01

    Pre-verbal infants and non-human animals associate small numbers with the left space and large numbers with the right space. Birds and primates, trained to identify a given position in a sagittal series of identical positions, whenever required to respond on a left/right oriented series, referred the given position starting from the left end. Here, we extended this evidence by selectively investigating the role of either cerebral hemisphere, using the temporary monocular occlusion technique. In birds, lacking the corpus callosum, visual input is fed mainly to the contralateral hemisphere. We trained 4-day-old chicks to identify the 4th element in a sagittal series of 10 identical elements. At test, the series was identical but left/right oriented. Test was conducted in right monocular, left monocular or binocular condition of vision. Right monocular chicks pecked at the 4th right element; left monocular and binocular chicks pecked at the 4th left element. Data on monocular chicks demonstrate that both hemispheres deal with an ordinal (sequential) task. Data on binocular chicks indicate that the left bias is linked to a right hemisphere dominance, that allocates the attention toward the left hemispace. This constitutes a first step towards understanding the neural basis of number space mapping. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Functional specialization of the left ventral parietal cortex in working memory

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    Jennifer Lou Langel

    2014-06-01

    Full Text Available The function of the ventral parietal cortex (VPC is subject to much debate. Many studies suggest a lateralization of function in the VPC, with the left hemisphere facilitating verbal working memory and the right subserving stimulus-driven attention. However, many attentional tasks elicit activity in the VPC bilaterally. To elucidate the potential divides across the VPC in function, we assessed the pattern of activity in the VPC bilaterally across two tasks that require different demands, an oddball attentional task with low working memory demands and a working memory task. An anterior region of the VPC was bilaterally active during novel targets in the oddball task and during retrieval in WM, while more posterior regions of the VPC displayed dissociable functions in the left and right hemisphere, with the left being active during the encoding and retrieval of WM, but not during the oddball task and the right showing the reverse pattern. These results suggest that bilateral regions of the anterior VPC subserve non-mnemonic processes, such as stimulus-driven attention during WM retrieval and oddball detection. The left posterior VPC may be important for speech-related processing important for both working memory and perception, while the right hemisphere is more lateralized for attention.

  16. Studying hemispheric lateralization during a Stroop task by near-infrared spectroscopy

    Science.gov (United States)

    Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

    2014-03-01

    We measured hemodynamic activity of the prefrontal cortex (PFC) during a Chinese color-word matching Stroop task using a homemade continuous-wave NIRS system. Two probes were placed separately over the left and the right PFC. Wavelet transform coherence (WTC) analysis was employed to calculate coherences between all channels of the same probe pairwise to obtain the intrahemispheric functional connectivity for each side of the PFC. The intrahemispheric functional connectivities in both sides of PFC were stronger during the incongruent task compared to that of the neutral task, but only the left intrahemispheric functional connectivity showed a significant Stroop effect. In addition to the Stroop effect, for the incongruent or the neutral task, there was also a leftward lateralization. The results indicate that, compared with traditional activation, NIRS-based connectivity is more sensitive for identifying hemispheric lateralization.

  17. Hemispheric specialization in children as reflected in the longitudinal development of ear asymmetry.

    Science.gov (United States)

    Bakker, D J; Hoefkens, M; Van der Vlugt, H

    1979-12-01

    The longitudinal development of ear asymmetry has been investigated in two samples of kindergarten and primary school children over an age range of six years. Ear preference in a dichotic digit test, administered four times, did not appear to be affected by age and sex: right ear advantage was predominant at all times. Individual comparison showed the development of ear advantage to depend on initial preference. Initially left eared subjects when changing ear advantage do so from left to right at early and from right to left at later school ages. The left-right shift may be due to the school teaching of linguistic skills which could selectively activate the left cerebral hemisphere. This explanation is supported by the finding that initially right eared subjects tended to conserve that preference at early school ages. Acknowledgements. We would like to thank Mr. P. Borgman and his staff of the Johannesschool in Amsterdam as well as their pupils who did not protest despite being examined year after year. The cooperation of the Free University Audio-Visual Center (Mr. Fred Van Hilst) is kindly acknowledged. Finally we would like to thank Dr. Paul Harris who was willing to read the English text critically and all others who assisted in the completion of this research.

  18. Hypothalamic digoxin, hemispheric dominance, and neurobiology of love and affection.

    Science.gov (United States)

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-05-01

    The human hypothalamus produces an endogenous membrane Na+-K+ ATPase inhibitor, digoxin, which can regulate neuronal transmission. The digoxin status and neurotransmitter patterns were studied in individuals with a predilection to fall in love. It was also studied in individuals with differing hemispheric dominance to find out the role of cerebral dominance in this respect. In individuals with a predilection to fall in love there was decreased digoxin synthesis, increased membrane Na+-K+ ATPase activity, decreased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and increased tyrosine catabolites (dopamine, noradrenaline, and morphine). This pattern correlated with that obtained in left hemispheric chemical dominance. Hemispheric dominance and hypothalamic digoxin could regulate the predisposition to fall in love.

  19. Children with autism show reduced somatosensory response: an MEG study.

    Science.gov (United States)

    Marco, Elysa J; Khatibi, Kasra; Hill, Susanna S; Siegel, Bryna; Arroyo, Monica S; Dowling, Anne F; Neuhaus, John M; Sherr, Elliott H; Hinkley, Leighton N B; Nagarajan, Srikantan S

    2012-10-01

    The neural underpinnings of sensory processing differences in autism remain poorly understood. This prospective magnetoencephalography (MEG) study investigates whether children with autism show atypical cortical activity in the primary somatosensory cortex (S1) in comparison with matched controls. Tactile stimuli were clearly detectable, and painless taps were applied to the distal phalanx of the second (D2) and third (D3) fingers of the right and left hands. Three tactile paradigms were administered: an oddball paradigm (standard taps to D3 at an interstimulus interval (ISI) of 0.33 and deviant taps to D2 with ISI ranging from 1.32 s to 1.64 s); a slow-rate paradigm (D2) with an ISI matching the deviant taps in the oddball paradigm; and a fast-rate paradigm (D2) with an ISI matching the standard taps in the oddball. Study subjects were boys (age 7-11 years) with and without autism disorder. Sensory behavior was quantified using the Sensory Profile questionnaire. Boys with autism exhibited smaller amplitude left hemisphere S1 response to slow and deviant stimuli during the right-hand paradigms. In post-hoc analysis, tactile behavior directly correlated with the amplitude of cortical response. Consequently, the children were re-categorized by degree of parent-report tactile sensitivity. This regrouping created a more robust distinction between the groups with amplitude diminution in the left and right hemispheres and latency prolongation in the right hemisphere in the deviant and slow-rate paradigms for the affected children. This study suggests that children with autism have early differences in somatosensory processing, which likely influence later stages of cortical activity from integration to motor response. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.

  20. Different distributions of the 5-HT reuptake complex and the postsynaptic 5-HT(2A) receptors in Brodmann areas and brain hemispheres.

    Science.gov (United States)

    Rosel, Pilar; Arranz, Belén; Urretavizcaya, Mikel; Oros, Miguel; San, Luis; Vallejo, Julio; Navarro, Miguel Angel

    2002-08-30

    The aim of the present study was to determine the distribution of the presynaptic 5-HT reuptake complex and the 5-HT(2A) receptors through Brodmann areas from two control subjects, together with the possible existence of laterality between both brain hemispheres. A left laterality was observed in the postsynaptic 5-HT(2A) binding sites, with significantly higher B(max) values in the left frontal and cingulate cortex. In frontal cortex, [3H]imipramine and [3H]paroxetine binding showed the highest B(max) values in areas 25, 10 and 11. In cingulate cortex, the highest [3H]imipramine and [3H]paroxetine B(max) values were noted in Brodmann area 33 followed by area 24, while postsynaptic 5-HT(2A) receptors were mainly distributed through Brodmann areas 23 and 29. In temporal cortex, the highest [3H]imipramine and [3H]paroxetine B(max) was noted in Brodmann areas 28 and 34, followed by areas 35 and 38. All Brodmann areas from parietal cortex (1, 2, 3, 4, 5, 6, 7, 39, 40 and 43) showed similar presynaptic and postsynaptic binding values. In occipital cortex no differences were observed with regard to the brain hemisphere or to the Brodmann area (17, 18 and 19). These results suggest the need to carefully define the brain hemisphere and the Brodmann areas studied, as well to avoid comparisons between studies including different Brodmann areas or brain hemispheres.

  1. Western Hemisphere Knowledge Partnerships

    Science.gov (United States)

    Malone, T. F.

    2001-05-01

    , and application of knowledge concerning the nature of -- and interaction among -- matter, living organisms, energy, information, and human behavior. This strategy calls for innovative partnerships among the physical, biological, health, and social sciences, engineering, and the humanities. New kinds of partnership must also be forged among academia, business and industry, governments, and nongovernmental organizations. Geophysicists can play an important role in these partnerships. A focus for these partnerships is to manage the individual economic productivity that drives both human development and global change. As world population approaches stability during the twenty-first century, individual economic productivity will be the critical link between the human and the natural systems on planet Earth. AGU is among a core group of individuals and institutions proposing Western Hemisphere Knowledge Partnerships (WHKP) to test the hypothesis that knowledge, broadly construed, is an important organizing principle in choosing a path into the future. The WHKP agenda includes: (1) life-long learning, (2) the health and resilience of natural ecosystems, (3) eco-efficiency in economic production and consumption, (4) extension of national income accounts, (5) environmentally benign sources of energy, (6) delivery of health care, (7) intellectual property rights, and (8) networks for action by local communities.Collaboratories and distance education technologies will be major tools. A panel of experts will explore this proposal.

  2. Writing induces a right hemisphere linguistic advantage in dysphonetic dyslexic children: implications for attention and capacity models of laterality.

    Science.gov (United States)

    Kershner, J; Henninger, P; Cooke, W

    1984-01-01

    An experiment demonstrated a complete hemispheric processing reversal in 10 male, dysphonetic dyslexic children that occurred during a dichotic listening test of their verbal working memory. Requiring a written response to dichotic digits produced a right hemisphere/left ear superiority in the dysphonetic dyslexics whereas normal subjects and other dyslexics maintained a left hemisphere/right ear advantage. This reversal was unaffected by changes in task difficulty. A second experiment assessed the influence on producing the reversal of concurrent manual interference with left hemisphere verbal processing (responding orally vs. manually) and selective right hemisphere priming (Forward Writing vs. Backward Writing). The dysphonetic children reverted to a strong left hemisphere superiority when recalling the dichotic digits orally. Backward writing produced no ear advantage in either direction. The findings suggest that dysphonetic dyslexia may be related to (1) left hemisphere processing demands that exceed capacity, (2) easily activated right hemisphere processing strategies and (3) failure to coordinate linguistic processing interhemispherically. The results supported a novel hybrid conceptualization of dyslexia consisting of a synthesis of selective activation, and dual processor-limited capacity, theories.

  3. Conjugating Time and Frequency: Hemispheric Specialization, Acoustic Uncertainty, and the Mustached Bat

    Directory of Open Access Journals (Sweden)

    Stuart Dante Washington

    2015-04-01

    Full Text Available A prominent hypothesis of hemispheric specialization for human speech and music, states that the left and right auditory cortices (ACs are respectively specialized for precise calculation of two canonically-conjugate variables: time and frequency. This spectral-temporal asymmetry does not account for sex, brain-volume, or handedness, and is in opposition to closed-system hypotheses that restrict this asymmetry to humans. Mustached bats have smaller brains, but greater ethological pressures to develop such a spectral-temporal asymmetry, than humans. Using the Heisenberg-Gabor Limit (i.e., the mathematical basis of the spectral-temporal asymmetry to frame mustached bat literature, we show that recent findings in bat AC (1 support the notion that hemispheric specialization for speech and music is based on hemispheric differences in temporal and spectral resolution, (2 discredit closed-system, handedness, and brain-volume theories, (3 underscore the importance of sex differences, and (4 provide new avenues for phonological research.

  4. Evidence of hemispheric specialization in marmosets (Callithrix penicillata using tympanic membrane thermometry

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    Tomaz C.

    2003-01-01

    Full Text Available Recent studies have employed tympanic thermometry to assess lateralization of cognitive and emotional functions in primates. However, no studies using this technique have investigated the possibility of hemispheric specialization in New World monkeys. Therefore, the aim of the present study was to investigate tympanic membrane (TM temperature asymmetries and their possible correlation with stress responses in marmosets (Callithrix penicillata. Infrared TM thermometry was completed bilaterally in 24 animals (14 males and 10 females during a stressful situation of capture and restraint. There were no significant differences between gender. A significant negative correlation was observed between TM temperature of the right ear and the number of captures (r = -0.633; P<0.001. Subjects with a more frequent previous history of captures (5 to 9 captures; N = 11 showed lower TM temperature when compared to those with fewer previous captures (1 to 4 captures; N = 13. No differences were observed for the left TM temperature. These results suggest that under intense emotional challenge (capture and restraint there is a stronger activation of the neural structures situated in the right brain hemisphere. Taken together, the data reveal for the first time evidence of hemispheric specialization in emotional physiological processing in a New World monkey.

  5. A Comparative Study Of Nerve Conduction Velocity Between Left And Right Handed Subjects.

    Science.gov (United States)

    Patel, Anup; Mehta, Anju

    2012-01-01

    Nerve conduction velocity is being used as a widespread measure of diagnosis of nerve function abnormalities. Dependence of nerve conduction parameters on intrinsic factors like age and sex, as well as extrinsic factors like temperature is well known. Lateralization of various cerebral functions like speech, language, visuospatial relations, analysis of face, recognition of musical themes and use of hand for fine motor movements have also been studied. Some differences have been noted between left and right hander for nerve conduction. The aim of this study is to compare the nerve conduction velocity between left handed and right handed subjects using median nerve and find out whether there is any difference in nerve conduction velocity (motor or sensory) with handedness. The study was carried out in students of B J Medical College by the use of standard 2 channel physiograph. Comparison of motor and sensory nerve conduction velocity between left and right handed subjects was done under paired-t test. Hemispheric specialization is primarily responsible for difference of dexterity. Some skills like music, sports activities are also due to hemispheric difference. On comparison of nerve conduction velocity between left and right handed persons the study shows that there is significant difference in sensory nerve conduction velocity between left and right handed subjects. From the results we can conclude that there should be different set of standards for sensory nerve conduction velocity of left and right handed subjects.

  6. Improving ideomotor limb apraxia by electrical stimulation of the left posterior parietal cortex.

    Science.gov (United States)

    Bolognini, Nadia; Convento, Silvia; Banco, Elisabetta; Mattioli, Flavia; Tesio, Luigi; Vallar, Giuseppe

    2015-02-01

    Limb apraxia, a deficit of planning voluntary gestures, is most frequently caused by damage to the left hemisphere, where, according to an influential neurofunctional model, gestures are planned, before being executed through the motor cortex of the hemisphere contralateral to the acting hand. We used anodal transcranial direct current stimulation delivered to the left posterior parietal cortex (PPC), the right motor cortex (M1), and a sham stimulation condition, to modulate the ability of six left-brain-damaged patients with ideomotor apraxia, and six healthy control subjects, to imitate hand gestures, and to perform skilled hand movements using the left hand. Transcranial direct current stimulation delivered to the left PPC reduced the time required to perform skilled movements, and planning, but not execution, times in imitating gestures, in both patients and controls. In patients, the amount of decrease of planning times brought about by left PPC transcranial direct current stimulation was influenced by the size of the parietal lobe damage, with a larger parietal damage being associated with a smaller improvement. Of interest from a clinical perspective, left PPC stimulation also ameliorated accuracy in imitating hand gestures in patients. Instead, transcranial direct current stimulation to the right M1 diminished execution, but not planning, times in both patients and healthy controls. In conclusion, by using a transcranial stimulation approach, we temporarily improved ideomotor apraxia in the left hand of left-brain-damaged patients, showing a role of the left PPC in planning gestures. This evidence opens up novel perspectives for the use of transcranial direct current stimulation in the rehabilitation of limb apraxia. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Impairment of language is related to left parieto-temporal glucose metabolism in aphasic stroke patients.

    Science.gov (United States)

    Karbe, H; Szelies, B; Herholz, K; Heiss, W D

    1990-02-01

    Twenty-six aphasic patients who had an ischaemic infarct in the territory of the left middle cerebral artery (MCA) were investigated. Cranial computed tomography (CT) showed various lesion sites: infarcts restricted to cortical structures in 12 patients, combined cortical and subcortical infarcts in 7 and isolated subcortical infarcts sparing the left cortex in another 7 cases. 18F-2-fluoro-2-deoxyglucose positron emission tomography revealed remote hypometabolism of the left convexity cortex and of the left basal ganglia, which was extended further than the morphological infarct zone in all cases. Types and degrees of aphasia were classified using the Aachener Aphasie Test (AAT): 10 patients had global aphasia, 2 Broca's, 5 Wernicke's, and 5 amnesic aphasia. Four patients suffered from minimal or residual aphasic symptoms. The AAT results were compared with the regional cerebral metabolic rates of glucose of the left hemisphere. Irrespective of the infarct location all five AAT subtests (Token test, repetition, written language, confrontation naming, auditory and reading comprehension) were closely correlated among each other and with left parieto-temporal metabolic rates, whereas left frontal and left basal ganglia metabolism showed no significant correlation. The close relation between left temporo-parietal functional activity and all five AAT subtests suggests that the different aspects of aphasia tested by AAT can be related to a common disorder of language processing in those areas.

  8. Structural hemispheric asymmetries underlie verbal Stroop performance.

    Science.gov (United States)

    Vallesi, Antonino; Mazzonetto, Ilaria; Ambrosini, Ettore; Babcock, Laura; Capizzi, Mariagrazia; Arbula, Sandra; Tarantino, Vincenza; Semenza, Carlo; Bertoldo, Alessandra

    2017-09-29

    Performance on tasks involving cognitive control such as the Stroop task is often associated with left lateralized brain activations. Based on this neuro-functional evidence, we tested whether leftward structural grey matter asymmetries would also predict inter-individual differences in combatting Stroop interference. To check for the specificity of the results, both a verbal Stroop task and a spatial one were administered to a total of 111 healthy young individuals, for whom T1-weighted magnetic resonance imaging (MRI) images were also acquired. Surface thickness and area estimations were calculated using FreeSurfer. Participants' hemispheres were registered to a symmetric template and Laterality Indices (LI) for the surface thickness and for the area at each vertex in each participant were computed. The correlation of these surface LI measures with the verbal and spatial Stroop effects (incongruent-congruent difference in trial performance) was assessed at each vertex by means of general linear models at the whole-brain level. We found a significant correlation between performance and surface area LI in an inferior posterior temporal cluster (overlapping with the so-called visual word form area, VWFA), with a more left-lateralized area in this region associated with a smaller Stroop effect only in the verbal task. These results point to an involvement of the VWFA for higher-level processes based on word reading, including the suppression of this process when required by the task, and could be interpreted in the context of cross-hemispheric rivalry. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Current dipole orientation and distribution of epileptiform activity correlates with cortical thinning in left mesiotemporal epilepsy.

    Science.gov (United States)

    Reinsberger, Claus; Tanaka, Naoaki; Cole, Andrew J; Lee, Jong Woo; Dworetzky, Barbara A; Bromfield, Edward B; Hamiwka, Lorie; Bourgeois, Blaise F; Golby, Alexandra J; Madsen, Joseph R; Stufflebeam, Steven M

    2010-10-01

    To evaluate cortical architecture in mesial temporal lobe epilepsy (MTLE) with respect to electrophysiology, we analyze both magnetic resonance imaging (MRI) and magnetoencephalography (MEG) in 19 patients with left MTLE. We divide the patients into two groups: 9 patients (Group A) have vertically oriented antero-medial equivalent current dipoles (ECDs). 10 patients (Group B) have ECDs that are diversely oriented and widely distributed. Group analysis of MRI data shows widespread cortical thinning in Group B compared with Group A, in the left hemisphere involving the cingulate, supramarginal, occipitotemporal and parahippocampal gyri, precuneus and parietal lobule, and in the right hemisphere involving the fronto-medial, -central and -basal gyri and the precuneus. These results suggest that regardless of the presence of hippocampal sclerosis, in a subgroup of patients with MTLE a large cortical network is affected. This finding may, in part, explain the unfavorable outcome in some MTLE patients after epilepsy surgery. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Enhancing verbal creativity: modulating creativity by altering the balance between right and left inferior frontal gyrus with tDCS.

    Science.gov (United States)

    Mayseless, N; Shamay-Tsoory, S G

    2015-04-16

    Creativity is the production of novel ideas that have value. Previous research indicated that while regions in the right hemisphere are implicated in the production of new ideas, damage to the left inferior frontal gyrus (IFG) is associated with increased creativity, indicating that the left IFG damage may have a "releasing" effect on creativity. To examine this, in the present study we used transcranial direct current stimulation (tDCS) to modulate activity of the right and the left IFG. In the first experiment we show that whereas anodal tDCS over the right IFG coupled with cathodal tDCS over the left IFG increases creativity as measured by a verbal divergent thinking task, the reverse stimulation does not affect creative production. To further confirm that only altering the balance between the two hemispheres is crucial in modulating creativity, in the second experiment we show that stimulation targeting separately the left IFG (cathodal stimulation) or the right IFG (anodal stimulation) did not result in changes in creativity as measured by verbal divergent thinking. These findings support the balance hypothesis, according to which verbal creativity requires a balance of activation between the right and the left frontal lobes, and more specifically, between the right and the left IFG. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. The compensatory dynamic of inter-hemispheric interactions in visuospatial attention revealed using rTMS and fMRI

    Directory of Open Access Journals (Sweden)

    Ela B Plow

    2014-04-01

    Full Text Available A balance of mutual tonic inhibition between bi-hemispheric posterior parietal cortices is believed to play an important role in bilateral visual attention. However, experimental support for this notion has been mainly drawn from clinical models of unilateral damage. We have previously shown that low-frequency repetitive TMS (rTMS over the intraparietal sulcus (IPS generates a contralateral attentional deficit in bilateral visual tracking. Here, we used functional Magnetic Resonance Imaging (fMRI to study whether rTMS temporarily disrupts the inter-hemispheric balance between bilateral IPS in visual attention. Following application of 1 Hz rTMS over the left IPS, subjects performed a bilateral visual tracking task while their brain activity was recorded using fMRI. Behaviorally, tracking accuracy was reduced immediately following rTMS. Areas ventro-lateral to left IPS, including inferior parietal lobule (IPL, lateral IPS (LIPS, and middle occipital gyrus (MoG, showed decreased activity following rTMS, while dorsomedial areas, such as Superior Parietal Lobule (SPL, Superior occipital gyrus (SoG, and lingual gyrus, as well as middle temporal areas (MT+, showed higher activity. The brain activity of the homologues of these regions in the un-stimulated, right hemisphere was reversed. Interestingly, the evolution of network-wide activation related to attentional behavior following rTMS showed that activation of most occipital synergists adaptively compensated for contralateral and ipsilateral decrement after rTMS, but that of parietal synergists, and SoG remained competing. This pattern of ipsilateral and contralateral activations empirically supports the hypothesized loss of inter-hemispheric balance that underlies clinical manifestation of visual attentional extinction.

  12. Asynchronous ripple oscillations between left and right hippocampi during slow-wave sleep.

    Science.gov (United States)

    Villalobos, Claudio; Maldonado, Pedro E; Valdés, José L

    2017-01-01

    Spatial memory, among many other brain processes, shows hemispheric lateralization. Most of the published evidence suggests that the right hippocampus plays a leading role in the manipulation of spatial information. Concurrently in the hippocampus, memory consolidation during sleep periods is one of the key steps in the formation of newly acquired spatial memory traces. One of the most characteristic oscillatory patterns in the hippocampus are sharp-wave ripple (SWR) complexes. Within this complex, fast-field oscillations or ripples have been demonstrated to be instrumental in the memory consolidation process. Since these ripples are relevant for the consolidation of memory traces associated with spatial navigation, and this process appears to be lateralized, we hypothesize that ripple events between both hippocampi would exhibit different temporal dynamics. We tested this idea by using a modified "split-hyperdrive" that allows us to record simultaneous LFPs from both right and left hippocampi of Sprague-Dawley rats during sleep. We detected individual events and found that during sleep periods these ripples exhibited a different occurrence patterns between hemispheres. Most ripple events were synchronous between intra- rather than inter-hemispherical recordings, suggesting that ripples in the hippocampus are independently generated and locally propagated within a specific hemisphere. In this study, we propose the ripples' lack of synchrony between left and right hippocampi as the putative physiological mechanism underlying lateralization of spatial memory.

  13. Asynchronous ripple oscillations between left and right hippocampi during slow-wave sleep.

    Directory of Open Access Journals (Sweden)

    Claudio Villalobos

    Full Text Available Spatial memory, among many other brain processes, shows hemispheric lateralization. Most of the published evidence suggests that the right hippocampus plays a leading role in the manipulation of spatial information. Concurrently in the hippocampus, memory consolidation during sleep periods is one of the key steps in the formation of newly acquired spatial memory traces. One of the most characteristic oscillatory patterns in the hippocampus are sharp-wave ripple (SWR complexes. Within this complex, fast-field oscillations or ripples have been demonstrated to be instrumental in the memory consolidation process. Since these ripples are relevant for the consolidation of memory traces associated with spatial navigation, and this process appears to be lateralized, we hypothesize that ripple events between both hippocampi would exhibit different temporal dynamics. We tested this idea by using a modified "split-hyperdrive" that allows us to record simultaneous LFPs from both right and left hippocampi of Sprague-Dawley rats during sleep. We detected individual events and found that during sleep periods these ripples exhibited a different occurrence patterns between hemispheres. Most ripple events were synchronous between intra- rather than inter-hemispherical recordings, suggesting that ripples in the hippocampus are independently generated and locally propagated within a specific hemisphere. In this study, we propose the ripples' lack of synchrony between left and right hippocampi as the putative physiological mechanism underlying lateralization of spatial memory.

  14. The effect of dual-hemisphere transcranial direct current stimulation over the parietal operculum on tactile orientation discrimination

    DEFF Research Database (Denmark)

    Fujimoto, Shuhei; Tanaka, Satoshi; Laakso, Ilkka

    2017-01-01

    The parietal operculum (PO) often shows ipsilateral activation during tactile object perception in neuroimaging experiments. However, the relative contribution of the PO to tactile judgment remains unclear. Here, we examined the effect of transcranial direct current stimulation (tDCS) over...... bilateral PO to test the relative contributions of the ipsilateral PO to tactile object processing. Ten healthy adults participated in this study, which had a double-blind, sham-controlled, cross-over design. Participants discriminated grating orientation during three tDCS and sham conditions. In the dual...... electrode. Importantly, dual-hemisphere tDCS with the anodal electrode over the left PO yielded a decreased threshold in the right finger compared with the uni-hemisphere tDCS condition. These results suggest that the ipsilateral PO inhibits tactile processing of grating orientation, indicating...

  15. Maurice Ravel and right-hemisphere musical creativity: influence of disease on his last musical works?

    Science.gov (United States)

    Amaducci, L; Grassi, E; Boller, F

    2002-01-01

    The problem of finding correspondence between a particular neuronal organization and a specific function of the human brain remains a central question of neuroscience. It is sometimes thought that language and music are two sides of the same intellectual coin, but research on brain-damaged patients has shown that the loss of verbal functions (aphasia) is not necessarily accompanied by a loss of musical abilities (amusia). Amusia without aphasia has also been described. This double dissociation indicates functional autonomy in these mental processes. Yet verbal and musical impairments often occur together. The global picture that emerges from studies of music and its neural substrate is by no means clear and much depends on which subjects and which aspect of musical abilities are investigated. An illustration of these concepts is provided by the case of the French composer Maurice Ravel, who suffered from a progressive cerebral disease of uncertain aetiology, with prominent involvement of the left hemisphere. As a result, Ravel experienced aphasia and apraxia and became unable to compose. The available facts favour a clinical diagnosis of primary progressive aphasia (PPA), with the possibility of an overlap with corticobasal degeneration (CBD). In view of Ravel's clinical history, we propose that two of his final compositions, the Bolero and the Concerto for the Left Hand, include certain patterns characteristic of right-hemisphere musical abilities and may show the influence of disease on the creative process.

  16. Research on measurement of residual stresses of hemispherical lithium hydride by blind-hole method

    Energy Technology Data Exchange (ETDEWEB)

    Bo, Lin, E-mail: linbo@caep.cn [China Academy of Engineering Physics, P.O. Box: 919-71, Mianyang 621900, Sichuan (China); Kaihui, He [China International Nuclear Fusion Energy Program Execution Center, 15B, Fuxing Rd, 100862 Beijing (China); Dongwei, Shan; Weicai, Yang; Yonggang, Chi; Mei, Liu; Jun, Shen [China Academy of Engineering Physics, P.O. Box: 919-71, Mianyang 621900, Sichuan (China)

    2014-04-15

    Highlights: • The residual stresses of sintered and machined lithium hydride of SR40 hyper-hemispherical and SR30 inner hemispherical sample were measured by blind-hole method. • The nearly 45 degrees direction residual stresses of SR40 hyper-hemisphere and SR30 inner hemisphere are the greatest stresses on spherical surface of lithium hydride samples. • The radial residual stress σ{sub r} of SR40 hyper-hemispherical and SR30 inner hemispherical sample is compressive stress and the circumferential residual stress σ{sub t} is tensile stress. - Abstract: The released strains of sintered and machined lithium hydride of SR40 hyper-hemispherical and SR30 inner hemispherical sample could be shown in the measuring process by blind-hole method. The residual stresses of lithium hydride sample were calculated with the formulas of residual stress and released strains. The results show that the nearly 45 degrees direction residual stresses of SR40 hyper-hemisphere and SR30 inner hemisphere are the greatest stresses on spherical surface of lithium hydride samples. The radial residual stress σ{sub r} of SR40 hyper-hemispherical and SR30 inner hemispherical sample is compressive stress and the circumferential residual stress σ{sub t} is tensile stress.

  17. The Effects of Multiple Script Priming on Word Recognition by the Two Cerebral Hemispheres: Implications for Discourse Processing

    Science.gov (United States)

    Faust, Miriam; Barak, Ofra; Chiarello, Christine

    2006-01-01

    The present study examined left (LH) and right (RH) hemisphere involvement in discourse processing by testing the ability of each hemisphere to use world knowledge in the form of script contexts for word recognition. Participants made lexical decisions to laterally presented target words preceded by centrally presented script primes (four…

  18. Factors Influencing Hemispheric Specialization.

    Science.gov (United States)

    1982-05-01

    results showed the presence of a LVF-!?v: superiority for the speed of response to faces. ’IniLs result -again is consrrucnt with Fardyck et effcn...1 i on tjimes for the Ymcci7 cry and C...,- o r ihi-n each of the tyo f -.tI irnulus mov -d<~’ oi ~t aiz ?-I d-f f er enctoesI. Tcr the am Lir Ci

  19. Hemispheric asymmetries in memory processes as measured in a false recognition paradigm.

    Science.gov (United States)

    Westerberg, Carmen E; Marsolek, Chad J

    2003-01-01

    Although memory differs in important ways between the left and right cerebral hemispheres, the nature of these differences remains controversial. We examined this issue in two experiments using a false memory paradigm that allowed novel tests of two theories that have not been assessed in a common paradigm previously. Lists of semantically related words (e.g., bed, rest, wake...), all highly associated to one "critical" word (e.g., sleep), were presented auditorily during a study phase. Memory for both the related words and the critical words was measured in a subsequent old/new recognition test using divided-visual-field word presentations. The most important results were that the ability to correctly reject previously unpresented words was greater when test items were presented to the right visual field/left hemisphere (RVF/LH) than to the left visual field/right hemisphere (LVF/RH) and that participants were more confident in correctly rejecting unpresented words when test items were presented to the RVF/LH than to the LVF/RH. Results were in line with the theory that associative activation of semantic information is restricted in the left hemisphere but diffuse in the right; however, these results contrasted with the theory that memory traces are interpretive in the left hemisphere but veridical in the right. A potential resolution to the seemingly contradictory theories of asymmetries in memory processing is briefly discussed.

  20. [Sex differences in hemispheric interference interaction during the memorizing of speech information].

    Science.gov (United States)

    Vol'f, N V

    1998-01-01

    Young men and women were monaurally and dichotically presented with 10-word lists which had to be afterwards reproduced in a written form. In dichotic pairs the signals were presented either synchronously or with time leads/lags in 50 ms between the ears. For each subject the interference effect was calculated of the right hemisphere to the left one and on the contrary. This index was taken as a measure of inhibitory interaction between the hemispheres. Lateral differences in hemispheric interference were well pronounced in men and absent in women. In women the interference effects on the first halves of the lists were stronger than in men and more pronounced than the effects on the second halves of the lists. The results are in agreement with the ideas about functional dissimilarity of processes underlying speech functions in the left and right brain hemispheres in men and women.

  1. Functional magnetic resonance imaging (fMRI) in patients with gliomas adjacent to classical language areas. Lateralization of activated prefrontal cortex is important in determining the dominant hemisphere

    International Nuclear Information System (INIS)

    Karibe, Hiroshi; Kumabe, Toshihiro; Shirane, Reizo; Yoshimoto, Takashi

    2003-01-01

    In patients with gliomas adjacent to classical language areas, lateralized activation of prefrontal cortex was assessed to determine language dominant hemisphere using functional magnetic resonance imaging (fMRI). Twelve patients presented with aphasias were studied. In all patients, either the left frontal operculum or left superior temporal gyri were adjacent to gliomas, suggesting all patients had left lateralization in hemispheric language dominance. Functional MRI was performed with a 1.5T scanner, with the sequence of gradient-echo type echo-planar imaging. As specific language tasks, verb, word, and capping generations were used. Using a cross-correlation analysis method, primary activation maps were generated using pixels with a correlation coefficient of >0.7. The lateralized activation of frontal operculum, superior temporal gyrus, and prefrontal cortex were assessed by calculating laterality index. Successful activation of frontal operculum was imaged in 11 of 12, in the superior temporal gyrus or prefrontal cortex. Three out of 11 cases had apparent activation lateralized in the right frontal operculum on fMRI, while 3 out of 12 cases showed activation in the superior temporal gyrus. On the other hand, all cases had apparent activation lateralized to the left prefrontal cortex. Significant activation of true language area may not be obtained in some cases with gliomas adjacent to classical language areas. In such cases, lateralization of apparent activation of prefrontal cortex may reflect lateralization in the dominant hemisphere. These result suggest that the assessment of apparent activation of prefrontal cortex lateralization is useful to determine the language dominant hemisphere. (author)

  2. Excitability of the motor cortex ipsilateral to the moving body side depends on spatio-temporal task complexity and hemispheric specialization.

    Directory of Open Access Journals (Sweden)

    Femke E van den Berg

    Full Text Available Unilateral movements are mainly controlled by the contralateral hemisphere, even though the primary motor cortex ipsilateral (M1(ipsi to the moving body side can undergo task-related changes of activity as well. Here we used transcranial magnetic stimulation (TMS to investigate whether representations of the wrist flexor (FCR and extensor (ECR in M1(ipsi would be modulated when unilateral rhythmical wrist movements were executed in isolation or in the context of a simple or difficult hand-foot coordination pattern, and whether this modulation would differ for the left versus right hemisphere. We found that M1(ipsi facilitation of the resting ECR and FCR mirrored the activation of the moving wrist such that facilitation was higher when the homologous muscle was activated during the cyclical movement. We showed that this ipsilateral facilitation increased significantly when the wrist movements were performed in the context of demanding hand-foot coordination tasks whereas foot movements alone influenced the hand representation of M1(ipsi only slightly. Our data revealed a clear hemispheric asymmetry such that MEP responses were significantly larger when elicited in the left M1(ipsi than in the right. In experiment 2, we tested whether the modulations of M1(ipsi facilitation, caused by performing different coordination tasks with the left versus right body sides, could be explained by changes in short intracortical inhibition (SICI. We found that SICI was increasingly reduced for a complex coordination pattern as compared to rest, but only in the right M1(ipsi. We argue that our results might reflect the stronger involvement of the left versus right hemisphere in performing demanding motor tasks.

  3. Impacts of hemispheric solar geoengineering on tropical cyclone frequency.

    Science.gov (United States)

    Jones, Anthony C; Haywood, James M; Dunstone, Nick; Emanuel, Kerry; Hawcroft, Matthew K; Hodges, Kevin I; Jones, Andy

    2017-11-14

    Solar geoengineering refers to a range of proposed methods for counteracting global warming by artificially reducing sunlight at Earth's surface. The most widely known solar geoengineering proposal is stratospheric aerosol injection (SAI), which has impacts analogous to those from volcanic eruptions. Observations following major volcanic eruptions indicate that aerosol enhancements confined to a single hemisphere effectively modulate North Atlantic tropical cyclone (TC) activity in the following years. Here we investigate the effects of both single-hemisphere and global SAI scenarios on North Atlantic TC activity using the HadGEM2-ES general circulation model and various TC identification methods. We show that a robust result from all of the methods is that SAI applied to the southern hemisphere would enhance TC frequency relative to a global SAI application, and vice versa for SAI in the northern hemisphere. Our results reemphasise concerns regarding regional geoengineering and should motivate policymakers to regulate large-scale unilateral geoengineering deployments.

  4. Do the Big Five personality traits predict individual differences in the left cheek bias for emotion perception?

    Science.gov (United States)

    Galea, Samantha; Lindell, Annukka K

    2016-01-01

    Like language, emotion is a lateralized function. Because the right hemisphere typically dominates emotion processing, people express stronger emotion on the left side of their face. This prompts a left cheek bias: we offer the left cheek to express emotion and rate left cheek portraits more emotionally expressive than right cheek portraits. Though the majority of the population show this left cheek bias (60-70%), individual differences exist but remain largely unexplained. Given that people with higher self-rated emotional expressivity show a stronger left cheek bias, personality variables associated with increased emotional expressivity and emotional intelligence, such as extraversion and openness, may help account for individual differences. The present study thus examined whether the Big Five traits predict left cheek preferences. Participants (M = 58, F = 116) completed the NEO-Five Factor Personality Inventory (NEO-FFI) [Costa, P. T. J., & McCrae, R. R. (1992). NEO PI-R professional manual. Odessa, FL: Psychological Assessment Resources] and viewed pairs of left and right cheek images (half mirror-reversed); participants made forced-choice decisions, indicating which image in each pair looked happier. Hierarchical regression indicated that neither trait extraversion nor openness predicted left cheek selections, with NEO-FFI personality subscales accounting for negligible variance in preferences. As the Big Five traits have been discounted, exploration of other potential contributors to individual differences in the left cheek bias is clearly needed.

  5. Common hemisphericity of language and music in a musician. A case report.

    Science.gov (United States)

    Hofman, S; Klein, C; Arlazoroff, A

    1993-06-01

    Aphasia coupled with amusia is reported in a 73-year-old male musician who was a lawyer by profession. This condition followed an ischemic stroke in the lateral aspect of the parieto-occipital region of the left hemisphere. The patient's music production exhibits jargon amusia, similar to that in his verbal production. This case supports the thesis that language and music may share a common hemisphere.

  6. The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.

    Science.gov (United States)

    Jeong, Su Keun; Xu, Yaoda

    2016-08-01

    The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.

  7. The measurement of blood flow in the cerebral hemispheres using a radioactive tracer

    International Nuclear Information System (INIS)

    Calegaro, J.U.M.; Reis, J.M.M. dos; Lopes, P.G.; Ribeiro, J.I.C.; Mansano, A.

    1978-01-01

    The modified Olendorf technique to measure the passage of a non-diffusible radioactive tracer through the cerebral hemispheres is described. The results given as brain transit time presents the following normal values: right hemisphere = 11,0 +- 2,8s (s.d.); left hemisphere = 11,0 +- 2,9s (s.d.). The equipment used is a two scintillation detectors sistem (with flat field collimation) with simultaneous chard recorder. The values obtained are taken as cerebral blood flow index. From 20 patients studied, 12 have obstructive carotid [pt

  8. Models of hemispheric specialization in facial emotion perception--a reevaluation.

    Science.gov (United States)

    Najt, Pablo; Bayer, Ulrike; Hausmann, Markus

    2013-02-01

    A considerable amount of research on functional cerebral asymmetries (FCAs) for facial emotion perception has shown conflicting support for three competing models: (i) the Right Hemisphere Hypothesis, (ii) the Valence-Specific Hypothesis, and (iii) the Approach/Withdrawal model. However, the majority of studies evaluating the Right Hemisphere or the Valence-Specific Hypotheses are rather limited by the small number of emotional expressions used. In addition, it is difficult to evaluate the Approach/Withdrawal Hypothesis due to insufficient data on anger and FCAs. The aim of the present study was (a) to review visual half field (VHF) studies of hemispheric specialization in facial emotion perception and (b) to reevaluate empirical evidence with respect to all three partly conflicting hypotheses. Results from the present study revealed a left visual field (LVF)/right hemisphere advantage for the perception of angry, fearful, and sad facial expressions and a right visual field (RVF)/left hemisphere advantage for the perception of happy expressions. Thus, FCAs for the perception of specific facial emotions do not fully support the Right Hemisphere Hypothesis, the Valence-Specific Hypothesis, or the Approach/Withdrawal model. A systematic literature review, together with the results of the present study, indicate a consistent LVF/right hemisphere advantage only for a subset of negative emotions including anger, fear and sadness, rather suggesting a "negative (only) valence model." PsycINFO Database Record (c) 2013 APA, all rights reserved.

  9. The time window for successful right-hemispheric language reorganization in children.

    Science.gov (United States)

    Lidzba, Karen; Küpper, Hanna; Kluger, Gerhard; Staudt, Martin

    2017-09-01

    To identify, in a retrospective, observational study, the time window during which successful right-hemispheric language reorganization is possible after left-hemispheric brain damage. 25 patients (10 females; age 6-41 years; ≥12 months after insult; age at insult 0;3-15;11 years) with acute, language-relevant left-hemispheric insults acquired during childhood and adolescence completed questionnaires for self-assessment of language problems. 12 patients of those reporting no (n = 8) or only moderate (n = 4) language problems participated in language fMRI. Language outcome of lesions occurring before 5 years of age (n = 7) was always favorable, and language was right-lateralized (2 patients: age at lesion reorganization (fMRI available in 4). The combination of normal language outcome and right-hemispheric language reorganization after a left-hemispheric lesion sustained after the neonatal period is extremely rare. Functionally sufficient right-hemispheric language was documented in only two patients with lesions acquired before two years of age. Copyright © 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  10. Hemispheric Specialization and Functional Plasticity during Development.

    Science.gov (United States)

    Levine, Susan Cohen

    1983-01-01

    Reviews literature on hemispheric specialization. Argues that foundations of hemispheric specialization are present very early in life and that children's greater ability to recover functions following brain injury suggests developmental changes in brain organization. (CMG)

  11. A comparison of brain activity associated with language production in brain tumor patients with left and right sided language laterality.

    Science.gov (United States)

    Jansma, J M; Ramsey, N; Rutten, G J

    2015-12-01

    Language dominance is an important factor for clinical decision making in brain tumor surgery. Functional MRI can provide detailed information about the organization of language in the brain. One often used measure derived from fMRI data is the laterality index (LI). The LI is typically based on the ratio between left and right brain activity in a specific region associated with language. Nearly all fMRI language studies show language-related activity in both hemispheres, and as a result the LI shows a large range of values. The clinical significance of the variation in language laterality as measured with the LI is still under debate. In this study, we tested two hypotheses in relation to the LI, measured in Broca's region, and it's right hemisphere homologue: 1: the level of activity in Broca's and it's right hemisphere homologue is mirrored for subjects with an equal but opposite LI; 2: the whole brain language activation pattern differs between subjects with an equal but opposite LI. One hundred sixty-three glioma and meningioma patients performed a verb generation task as part of a standard clinical protocol. We calculated the LI in the pars orbitalis, pars triangularis and pars opercularis of the left inferior frontal gyrus, referred to as Broca's region from here on. In our database, 21 patients showed right lateralized activity, with a moderate average level (-0.32). A second group of 21 patients was selected from the remaining group, for equal but opposite LI (0.32). We compared the level and distribution of activity associated with language production in the left and right hemisphere in these two groups. Patients with left sided laterality showed a significantly higher level of activity in Broca's region than the patients with right sided laterality. However, both groups showed no difference in level of activity in Broca's homologue region in the right hemisphere. Also, we did not see any difference in the pattern of activity between patients with left

  12. Hemispheric ultra-wideband antenna.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2006-04-01

    This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.

  13. Hemispheric Laterality in Music and Math

    Science.gov (United States)

    Szirony, Gary Michael; Burgin, John S.; Pearson, L. Carolyn

    2008-01-01

    Hemispheric laterality may be a useful concept in teaching, learning, training, and in understanding more about human development. To address this issue, a measure of hemispheric laterality was compared to musical and mathematical ability. The Human Information Processing Survey (HIPS) instrument, designed to measure hemispheric laterality, was…

  14. INDIVIDUAL PROFILE OF FUNCTIONAL HEMISPHERIC ASYMMETRY AND QUALITY OF LIFE IN PATIENTS WITH PARKINSON'S DISEASE

    Directory of Open Access Journals (Sweden)

    M. A. Bykanova

    2014-07-01

    Full Text Available Objective — to identify the relationship between the individual profile of functional hemispheric asymmetry (IPFA and lateralization of the Parkinson's disease (PD debut, as well as assess of their impact on anxiety and depressive disorders and quality of life of patients.Materials and methods. 70 patients with PD (28 men and 42 women, average age 63,1 ± 8,1 years with disease duration 48 [36, 72] months (Me [25 %; 75 %] were included. We used Hoehn and Yahr, UPDRS, EuroQol, PDQ-39 scales, scale of anxiety and Spielberger–Hanin Hamilton Depression. IPFA was determined using the protocol survey of 48 jobs during the period of inclusion of patients in the study.Results. In patients with right-sided IPFA right-sided debut of PD was more common (p < 0.05 and in patients with mixed IPFA — leftsided(p < 0.05 PD debut. There were no significant differences in levels of reactive, personal anxiety and depression at different IPFA dependingon the side of PD debut (p > 0.05 received. Quality of life scale PDQ-39 showed worse results in patients with right-in right IPFA debut in comparison with those in patients with left debut (p < 0.05. Quality of life by EuroQol-II scale was higher in patients with rightsided IPFA with the left debut of PD than in patients with right-debut (p < 0.05, and in patients with mixed IPFA with right debut compared to patients with left debut (p < 0.05.Conclusion. With the debut of PD in leading limb and preferential involvement of the dominant hemisphere poorer quality of life was observed. IPFA and clinical asymmetry did not affect on the level of anxiety and depressive disorders, which were revealed in more than twothirds of patients with PD.

  15. Semantic dementia and the left and right temporal lobes.

    Science.gov (United States)

    Snowden, Julie S; Harris, Jennifer M; Thompson, Jennifer C; Kobylecki, Christopher; Jones, Matthew; Richardson, Anna M; Neary, David

    2017-08-31

    Semantic dementia, a circumscribed disorder of semantic knowledge, provides a unique model for understanding the neural basis for semantic representation. The study addressed areas of contention: the relative roles of the left and right temporal lobe, the contribution of anterior versus posterior temporal cortex and the status of the anterior temporal lobes as amodal hub. Naming and word comprehension was examined in 41 semantic dementia patients, 31 with left-predominant and 10 right-predominant atrophy. In keeping with expectation, naming and comprehension were significantly poorer in left-predominant patients. Structural magnetic resonance image analysis, using a visual rating scale, showed strong inverse correlations between naming scores and severity of both left anterior and posterior temporal lobe atrophy. By contrast, comprehension performance was more strongly correlated with left posterior temporal atrophy. Analysis of naming errors revealed a correlation between anterior temporal atrophy and associative/functional descriptive responses, implying availability of semantic information. By contrast, 'don't know' responses, indicative of loss of semantic knowledge, were linked to left posterior temporal lobe atrophy. Semantic errors, the hallmark of semantic dementia, were linked to right hemisphere atrophy, especially the right posterior temporal lobe. Matched visual-verbal tasks (famous face and name identification, Pyramids and Palm trees pictures and words, animal knowledge from 3-D models and animal names) administered to nine patients elicited variable correspondence between performance on nonverbal and verbal versions of the task. Marked performance dissociations were demonstrated in some patients: poorer understanding of names/words in left-predominant patients and of faces/pictures/models in right-predominant cases. The findings are compatible with the notion of the anterior temporal lobes as areas of convergence, but are less easily accommodated

  16. Right-hemispheric processing of non-linguistic word features: implications for mapping language recovery after stroke.

    Science.gov (United States)

    Baumgaertner, Annette; Hartwigsen, Gesa; Roman Siebner, Hartwig

    2013-06-01

    Verbal stimuli often induce right-hemispheric activation in patients with aphasia after left-hemispheric stroke. This right-hemispheric activation is commonly attributed to functional reorganization within the language system. Yet previous evidence suggests that functional activation in right-hemispheric homologues of classic left-hemispheric language areas may partly be due to processing nonlinguistic perceptual features of verbal stimuli. We used functional MRI (fMRI) to clarify the role of the right hemisphere in the perception of nonlinguistic word features in healthy individuals. Participants made perceptual, semantic, or phonological decisions on the same set of auditorily and visually presented word stimuli. Perceptual decisions required judgements about stimulus-inherent changes in font size (visual modality) or fundamental frequency contour (auditory modality). The semantic judgement required subjects to decide whether a stimulus is natural or man-made; the phonologic decision required a decision on whether a stimulus contains two or three syllables. Compared to phonologic or semantic decision, nonlinguistic perceptual decisions resulted in a stronger right-hemispheric activation. Specifically, the right inferior frontal gyrus (IFG), an area previously suggested to support language recovery after left-hemispheric stroke, displayed modality-independent activation during perceptual processing of word stimuli. Our findings indicate that activation of the right hemisphere during language tasks may, in some instances, be driven by a "nonlinguistic perceptual processing" mode that focuses on nonlinguistic word features. This raises the possibility that stronger activation of right inferior frontal areas during language tasks in aphasic patients with left-hemispheric stroke may at least partially reflect increased attentional focus on nonlinguistic perceptual aspects of language. Copyright © 2012 Wiley Periodicals, Inc.

  17. The unification of mind: Integration of hemispheric semantic processing.

    Science.gov (United States)

    Hutchinson, Adele; Whitman, R Douglas; Abeare, Chris; Raiter, Jennifer

    2003-12-01

    Seventy-six participants performed a visual half-field lexical decision task at two different stimulus onset asynchronies (50 or 750 ms). Word targets were primed either by a highly associated word (e.g., CLEAN-DIRTY), a weakly associated word (e.g., CLEAN-TIDY), or an unrelated word (e.g., CLEAN-FAMILY) projected to either the same or opposite visual field (VF) as the target. In the short SOA, RVF-left hemisphere primes resulted in high associate priming regardless of target location (ipsilateral or contralateral to the prime) whereas LVF-right hemisphere primes produced both high and low associate priming across both target location conditions. In the long SOA condition, contralateral priming patterns converged, demonstrating only high associate priming in both VF locations. The results of this study demonstrate the critical role of interhemispheric transfer in semantic processing and indicate a need to elaborate current models of semantic processing.

  18. Positive schizotypy scores correlate with left visual field interference for negatively valenced emotional words: A lateralized emotional Stroop study.

    Science.gov (United States)

    Van Strien, Jan W; Van Kampen, Dirk

    2009-10-30

    Fourteen men scoring high and 14 men scoring low on a positive schizotypy scale participated in a lateralized emotional Stroop task. Vocal reaction times for color naming of neutral, positive and negative emotional words were recorded. Across participants, the color naming of neutral and emotional words was slightly faster to right than to left visual field presentations. In men with high scores on positive schizotypy, the presentation of negative words to the left visual field (right hemisphere) resulted in significant affective interference with color naming, which was significantly larger than in men with low scores. Correlational analysis also showed that positive schizotypy was significantly associated with emotional interference in response to LVF negative words. The outcome is discussed in terms of right hemispheric engagement in negative emotions in high positive schizotypic men.

  19. Phenological changes in the southern hemisphere.

    Directory of Open Access Journals (Sweden)

    Lynda E Chambers

    Full Text Available Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand, South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias, although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially

  20. Phenological Changes in the Southern Hemisphere

    Science.gov (United States)

    Chambers, Lynda E.; Altwegg, Res; Barbraud, Christophe; Barnard, Phoebe; Beaumont, Linda J.; Crawford, Robert J. M.; Durant, Joel M.; Hughes, Lesley; Keatley, Marie R.; Low, Matt; Morellato, Patricia C.; Poloczanska, Elvira S.; Ruoppolo, Valeria; Vanstreels, Ralph E. T.; Woehler, Eric J.; Wolfaardt, Anton C.

    2013-01-01

    Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically

  1. Phenological changes in the southern hemisphere.

    Science.gov (United States)

    Chambers, Lynda E; Altwegg, Res; Barbraud, Christophe; Barnard, Phoebe; Beaumont, Linda J; Crawford, Robert J M; Durant, Joel M; Hughes, Lesley; Keatley, Marie R; Low, Matt; Morellato, Patricia C; Poloczanska, Elvira S; Ruoppolo, Valeria; Vanstreels, Ralph E T; Woehler, Eric J; Wolfaardt, Anton C

    2013-01-01

    Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically

  2. Quality of life in patients with right- or left-sided brain tumours: literature review.

    Science.gov (United States)

    Palese, Alvisa; Lamanna, Francesca; Di Monte, Carmen; Calligaris, Sonia; Doretto, Mara; Criveller, Michela

    2008-06-01

    To determine if patients with left- or right-sided hemisphere neoplasm perceive their quality of life (QoL) differently. It is not clear whether patients with a lesion in the left hemisphere have a different QoL than those with a lesion in the right hemisphere. (1) In the pre-operative period, patients with a left-sided lesion may have different symptoms according to the position of the tumour. (2) Studies on patients with brain injury demonstrate an association between left frontal lesions and depression: depression can alter the patients' perception of QoL. (3) In the postoperative period, right-handed patients may be disadvantaged by surgical trauma to the motor cortex in the left hemisphere. (4) During the different phases of the disease, the various functions of the two hemispheres may influence the patient's capacity to control QoL; also, as suggested by authors, both the ego and the conscience are mostly located in the left hemisphere. This is the reason that patients with a left-sided lesion may perceive a worse QoL. A review of literature was carried out using the Medline database (1966-2007) and CINHAL (1982-2007), using the following Mesh Terms and key words: brain neoplasm, tumour or cancer, hemispheric dominance or laterality or right or left hemisphere, QoL. Seven studies emerged that documented non-homogeneous results and which included different populations. The association between QoL and the side of the lesion was evaluated. The lack of a substantial number of recent, robust follow-up studies investigating the QoL in patients at different stages of disease and treatment indicates that more research is needed. Relevance to clinical practice. Understanding the QoL in patients with brain neoplasm and the differences between right and left hemisphere sites of the neoplasm can help nurses develop different interventions and offer more guidance for effective clinical intervention.

  3. The perception of peripersonal space in right and left brain damage hemiplegic patients

    Directory of Open Access Journals (Sweden)

    Angela eBartolo

    2014-01-01

    Full Text Available Peripersonal space, as opposed to extrapersonal space, is the space that contains reachable objects and in which multisensory and sensorimotor integration is enhanced. Thus, the perception of peripersonal space requires combining information on the spatial properties of the environment with information on the current capacity to act. In support of this, recent studies have provided converging evidences that perceiving objects in peripersonal space activates a neural network overlapping with that subtending voluntary motor action and motor imagery. Other studies have also underlined the dominant role of the right hemisphere in motor planning and of the left hemisphere in on-line motor guiding, respectively. In the present study, we investigated the effect of a right or left hemiplegia in the perception of peripersonal space. 16 hemiplegic patients with brain damage to the left (LH or right (RH hemisphere and 8 matched healthy controls (HC performed a colour discrimination, a motor imagery and a reachability judgment task. Analyses of response times and accuracy revealed no variation among the three groups in the colour discrimination task, suggesting the absence of any specific perceptual or decisional deficits in the patient groups. In contrast, the patient groups revealed longer response times in the motor imagery task when performed in reference to the hemiplegic arm (RH and LH or to the healthy arm (RH. Moreover, RH group showed longer response times in the reachability judgement task, but only for stimuli located at the boundary of peripersonal space, which was furthermore significantly reduced in size. Considered together, these results confirm the crucial role of the motor system in motor imagery task and the perception of peripersonal space. They also revealed that right hemisphere damage has a more detrimental effect on reachability estimates, suggesting that motor planning processes contribute specifically to the perception of

  4. Individual Differences in Hemispheric Specialization

    Science.gov (United States)

    1987-11-01

    handers is of interest. Groups of dextro-sinistrals and stutterers (who were mostly right-handed) also had a left hand advantage. These findings were...in research of any sort. Procedure and objectives were not discussed with children or teachers . — • — - - w &BglS .-. ^’ Stimuli. The stimuli...any Q sort apparent to teachers or children. This led to the testing of two left- .^% handed children, but it was shown that

  5. Hemispheric asymmetries and gender influence Rembrandt's portrait orientations.

    Science.gov (United States)

    Schirillo, J A

    2000-01-01

    For centuries painters have predominantly painted portraits with the model's left-cheek facing the viewer. This has been even more prevalent with females ( approximately 68%) than males ( approximately 56%). Numerous portraits painted by Rembrandt typify this unexplained phenomenon. In a preliminary experiment, subjects judged 24 emotional and social character traits in 20 portraits by Rembrandt. A factor analysis revealed that females with their left cheek exposed were judged to be much less socially appealing than less commonly painted right-cheeked females. Conversely, the more commonly painted right-cheeked males were judged to be more socially appealing than either left-cheeked males or females facing either direction. It is hypothesized that hemispheric asymmetries regulating emotional facial displays of approach and avoidance influenced the side of the face Rembrandt's models exposed due to prevailing social norms. A second experiment had different subjects judge a different collection of 20 portraits by Rembrandt and their mirror images. Mirror-reversed images produced the same pattern of results as their original orientation counterparts. Consequently, hemispheric asymmetries that specify the emotional expression on each side of the face are posited to account for the obtained results.

  6. Hemispheric asymmetries in speech perception: sense, nonsense and modulations.

    Directory of Open Access Journals (Sweden)

    Stuart Rosen

    Full Text Available The well-established left hemisphere specialisation for language processing has long been claimed to be based on a low-level auditory specialization for specific acoustic features in speech, particularly regarding 'rapid temporal processing'.A novel analysis/synthesis technique was used to construct a variety of sounds based on simple sentences which could be manipulated in spectro-temporal complexity, and whether they were intelligible or not. All sounds consisted of two noise-excited spectral prominences (based on the lower two formants in the original speech which could be static or varying in frequency and/or amplitude independently. Dynamically varying both acoustic features based on the same sentence led to intelligible speech but when either or both acoustic features were static, the stimuli were not intelligible. Using the frequency dynamics from one sentence with the amplitude dynamics of another led to unintelligible sounds of comparable spectro-temporal complexity to the intelligible ones. Positron emission tomography (PET was used to compare which brain regions were active when participants listened to the different sounds.Neural activity to spectral and amplitude modulations sufficient to support speech intelligibility (without actually being intelligible was seen bilaterally, with a right temporal lobe dominance. A left dominant response was seen only to intelligible sounds. It thus appears that the left hemisphere specialisation for speech is based on the linguistic properties of utterances, not on particular acoustic features.

  7. It takes two-skilled recognition of objects engages lateral areas in both hemispheres.

    Directory of Open Access Journals (Sweden)

    Merim Bilalić

    Full Text Available Our object recognition abilities, a direct product of our experience with objects, are fine-tuned to perfection. Left temporal and lateral areas along the dorsal, action related stream, as well as left infero-temporal areas along the ventral, object related stream are engaged in object recognition. Here we show that expertise modulates the activity of dorsal areas in the recognition of man-made objects with clearly specified functions. Expert chess players were faster than chess novices in identifying chess objects and their functional relations. Experts' advantage was domain-specific as there were no differences between groups in a control task featuring geometrical shapes. The pattern of eye movements supported the notion that experts' extensive knowledge about domain objects and their functions enabled superior recognition even when experts were not directly fixating the objects of interest. Functional magnetic resonance imaging (fMRI related exclusively the areas along the dorsal stream to chess specific object recognition. Besides the commonly involved left temporal and parietal lateral brain areas, we found that only in experts homologous areas on the right hemisphere were also engaged in chess specific object recognition. Based on these results, we discuss whether skilled object recognition does not only involve a more efficient version of the processes found in non-skilled recognition, but also qualitatively different cognitive processes which engage additional brain areas.

  8. It Takes Two–Skilled Recognition of Objects Engages Lateral Areas in Both Hemispheres

    Science.gov (United States)

    Bilalić, Merim; Kiesel, Andrea; Pohl, Carsten; Erb, Michael; Grodd, Wolfgang

    2011-01-01

    Our object recognition abilities, a direct product of our experience with objects, are fine-tuned to perfection. Left temporal and lateral areas along the dorsal, action related stream, as well as left infero-temporal areas along the ventral, object related stream are engaged in object recognition. Here we show that expertise modulates the activity of dorsal areas in the recognition of man-made objects with clearly specified functions. Expert chess players were faster than chess novices in identifying chess objects and their functional relations. Experts' advantage was domain-specific as there were no differences between groups in a control task featuring geometrical shapes. The pattern of eye movements supported the notion that experts' extensive knowledge about domain objects and their functions enabled superior recognition even when experts were not directly fixating the objects of interest. Functional magnetic resonance imaging (fMRI) related exclusively the areas along the dorsal stream to chess specific object recognition. Besides the commonly involved left temporal and parietal lateral brain areas, we found that only in experts homologous areas on the right hemisphere were also engaged in chess specific object recognition. Based on these results, we discuss whether skilled object recognition does not only involve a more efficient version of the processes found in non-skilled recognition, but also qualitatively different cognitive processes which engage additional brain areas. PMID:21283683

  9. Smartphone based hemispherical photography for canopy structure measurement

    Science.gov (United States)

    Wan, Xuefen; Cui, Jian; Jiang, Xueqin; Zhang, Jingwen; Yang, Yi; Zheng, Tao

    2018-01-01

    The canopy is the most direct and active interface layer of the interaction between plant and environment, and has important influence on energy exchange, biodiversity, ecosystem matter and climate change. The measurement about canopy structure of plant is an important foundation to analyze the pattern, process and operation mechanism of forest ecosystem. Through the study of canopy structure of plant, solar radiation, ambient wind speed, air temperature and humidity, soil evaporation, soil temperature and other forest environmental climate characteristics can be evaluated. Because of its accuracy and effectiveness, canopy structure measurement based on hemispherical photography has been widely studied. However, the traditional method of canopy structure hemispherical photogrammetry based on SLR camera and fisheye lens. This method is expensive and difficult to be used in some low-cost occasions. In recent years, smartphone technology has been developing rapidly. The smartphone not only has excellent image acquisition ability, but also has the considerable computational processing ability. In addition, the gyroscope and positioning function on the smartphone will also help to measure the structure of the canopy. In this paper, we present a smartphone based hemispherical photography system. The system consists of smart phones, low-cost fisheye lenses and PMMA adapters. We designed an Android based App to obtain the canopy hemisphere images through low-cost fisheye lenses and provide horizontal collimation information. In addition, the App will add the acquisition location tag obtained by GPS and auxiliary positioning method in hemisphere image information after the canopy structure hemisphere image acquisition. The system was tested in the urban forest after it was completed. The test results show that the smartphone based hemispherical photography system can effectively collect the high-resolution canopy structure image of the plant.

  10. Hemispheric asymmetries in feature integration during visual word recognition.

    Science.gov (United States)

    Lindell, Annukka K; Arend, Isabel; Ward, Robert; Norton, Jennifer; Wathan, Jennifer

    2007-11-01

    Although the definitive source of the left hemisphere's superiority for visual word recognition remains illusive, some argue that the left (LH) and right (RH) hemispheres engage different strategies during early perceptual processes involved in stimulus encoding. In particular, it is proposed that the LH treats a word as a unitary perceptual group whereas the RH processes the letters comprising a word as a series of individual perceptual units. The present study investigated support for this processing distinction by examining hemispheric strategies for temporal integration using Prinzmetal and Millis-Wright's (1984) feature-binding paradigm. A total of 20 participants identified the colour and identity of a target letter, presented within a three-letter word (e.g., ART) or nonword (e.g., HRF), directed to their left or right visual field. Errors were classified on the basis of whether they involved substitution of a colour present within the stimulus but at a different location (ON error), or the substitution of a colour not present within the stimulus (OFF error). As anticipated, for word stimuli there was a higher proportion of OFF errors associated with trials directed to the RH, consistent with the notion that the LH treats words as single perceptual units and is hence biased toward miscombination of perceptual information present within the stimulus. The pattern of ON errors across stimulus type provided clear evidence of RH sequential encoding effects, with the number of errors increasing markedly across the ordinal position of the letters comprising the stimulus string. As such, these data provide new evidence that the LH's advantage for visual word recognition arises, at least in part, from the ability to encode verbal stimuli as single perceptual units.

  11. Recognition of emotion in hemifaces presented to the left and right visual fields.

    Science.gov (United States)

    Wedding, D; Cyrus, P

    1986-09-01

    Thirty-two right-handed subjects (16 males and 16 females) participated in a choice reaction time experiment replicating two previous studies which demonstrated the superiority of the left hemisphere in rapidly identifying facial emotion as either positive or negative. Slides of hemifaces split along the vertical axis, showing either positive (happiness, surprise) or negative (anger, disgust, or sadness) affect were presented tachistoscopically to either the left or right visual field. A 2 X 2 X 2 mixed ANOVA revealed main effects for visual field and type of affect. In contrast to earlier studies which presented full face stimuli, presentation of hemifaces produced a strong left visual field advantage and, as expected, positive faces produced faster reaction times than negative faces.

  12. Functional Ear (A)Symmetry in Brainstem Neural Activity Relevant to Encoding of Voice Pitch: A Precursor for Hemispheric Specialization?

    Science.gov (United States)

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Bidelman, Gavin M.; Smalt, Christopher J.

    2011-01-01

    Pitch processing is lateralized to the right hemisphere; linguistic pitch is further mediated by left cortical areas. This experiment investigates whether ear asymmetries vary in brainstem representation of pitch depending on linguistic status. Brainstem frequency-following responses (FFRs) were elicited by monaural stimulation of the left and…

  13. Inter-hemispheric integration of tactile-motor responses across body parts.

    Science.gov (United States)

    Tamè, Luigi; Longo, Matthew R

    2015-01-01

    In simple detection tasks, reaction times (RTs) are faster when stimuli are presented to the visual field or side of the body ipsilateral to the body part used to respond. This advantage, the crossed-uncrossed difference (CUD), is thought to reflect inter-hemispheric interactions needed for sensorimotor information to be integrated between the two cerebral hemispheres. However, it is unknown whether the tactile CUD is invariant when different body parts are stimulated. The most likely structure mediating such processing is thought to be the corpus callosum (CC). Neurophysiological studies have shown that there are denser callosal connections between regions that represent proximal parts of the body near the body midline and more sparse connections for regions representing distal extremities. Therefore, if the information transfer between the two hemispheres is affected by the density of callosal connections, stimuli presented on more distal regions of the body should produce a greater CUD compared to stimuli presented on more proximal regions. This is because interhemispheric transfer of information from regions with sparse callosal connections will be less efficient, and hence slower. Here, we investigated whether the CUD is modulated as a function of the different body parts stimulated by presenting tactile stimuli unpredictably on body parts at different distances from the body midline (i.e., Middle Finger, Forearm, or Forehead of each side of the body). Participants detected the stimulus and responded as fast as possible using either their left or right foot. Results showed that the magnitude of the CUD was larger on the finger (~2.6 ms) and forearm (~1.8 ms) than on the forehead (≃0.9 ms). This result suggests that the interhemispheric transfer of tactile stimuli varies as a function of the strength of callosal connections of the body parts.

  14. Determination of hemispheric emotional valence in individual subjects: A new approach with research and therapeutic implications

    Directory of Open Access Journals (Sweden)

    Polcari Ann

    2007-03-01

    Full Text Available Abstract Background Much has been theorized about the emotional properties of the hemispheres. Our review of the dominant hypotheses put forth by Schore, Joseph, Davidson, and Harmon-Jones on hemispheric emotional valences (HEV shows that none are supported by robust data. Instead, we propose that individual's hemispheres are organized to have differing HEVs that can be lateralized in either direction. Methods Probe auditory evoked potentials (AEP recorded during a neutral and an upsetting memory were used to assess HEV in 28 (20 F right-handed subjects who were either victims of childhood maltreatment (N = 12 or healthy controls. In a sub-population, we determined HEV by emotional response to lateral visual field stimulation (LVFS, in which vision is limited to one, then the other hemifield. We compare a number of morphometric and functional brain measures between individuals who have right-negative versus left-negative HEV. Results Using AEPs to determine HEV, we found 62% of controls and 67% of maltreated subjects had right negative HEV. There was a strong interaction between HEV-laterality and gender, which together accounted for 60% of individual variability in total grey matter volume (GMV. HEV-laterality was associated with differences in hippocampal volume, amygdala/hippocampal ratios, and measures of verbal, visual and global memory. HEV-laterality was associated also with different constellations of symptoms comparing maltreated subjects to controls. Emotional response to LVFS provided a convenient and complementary measure of HEV-laterality that correlated significantly with the HEVs determined by AEPs. Conclusion Our findings suggest that HEV-laterality, like handedness or gender, is an important individual difference with significant implications for brain and behavioral research, and for guiding lateralized treatments such as rTMS.

  15. Hemisphericity and creativity. Group process and the dream factory.

    Science.gov (United States)

    Loye, D

    1988-09-01

    Traditionally, creativity has been studied as an aspect of the psychology of personality. Recent brain research--for example, hemisphericity study--provides a new physiologic grounding for such studies. Particularly needed now are creativity studies to relate both brain physiology and personality to group process. This article is the report of such a study applying systems research to an exploration of creativity in the motion picture-television industry. Findings include the identification of both right and left brain models and creative phases within cycles phenomena in group process creativity. Implications for psychotherapy and a wide range of fields are examined.

  16. ARE LEFT HANDED SURGEONS LEFT OUT?

    OpenAIRE

    SriKamkshi Kothandaraman; Balasubramanian Thiagarajan

    2012-01-01

    Being a left-handed surgeon, more specifically a left-handed ENT surgeon, presents a unique pattern of difficulties.This article is an overview of left-handedness and a personal account of the specific difficulties a left-handed ENT surgeon faces.

  17. Hemispheric Lateralization of Resting-State Functional Connectivity of the Anterior Insula: Association with Age, Gender, and a Novelty-Seeking Trait

    Science.gov (United States)

    Kann, Sarah; Zhang, Sheng; Manza, Peter; Leung, Hoi-Chung

    2016-01-01

    Abstract Resting-state functional connectivity (rsFC) is widely used to examine cerebral functional organization. The imaging literature has described lateralization of insula activations during cognitive and affective processing. Evidence appears to support a role of the right-hemispheric insula in attentional orientation to salient stimulus, interoception, and physiological arousal, and a role of the left-hemispheric insula in cognitive and affective control, as well as perspective taking. In this study, in a large data set of healthy adults, we examined lateralization of the rsFC of the anterior insula (AI) by computing a laterality index (LI) of connectivity with 54 regions from the Automated Anatomic Labeling atlas. At a corrected threshold (p lateralized in connectivity with the dorsomedial prefrontal cortex, superior frontal gyrus, inferior frontal cortex, and posterior orbital gyrus and right lateralized in connectivity with the postcentral gyrus, supramarginal gyrus, and superior parietal lobule. In gender differences, women, but not men, showed right-lateralized connectivity to the thalamus. Furthermore, in a subgroup of participants assessed by the tridimensional personality questionnaire, novelty seeking is correlated with the extent of left lateralization of AI connectivity to the pallidum and putamen in men and with the extent of right lateralization of AI connectivity to the parahippocampal gyrus in women. These findings support hemispheric functional differentiation of the AI. PMID:27604154

  18. TMS stimulus-response asymmetry in left- and right-handed individuals.

    Science.gov (United States)

    Daligadu, Julian; Murphy, Bernadette; Brown, Jeff; Rae, Brendan; Yielder, Paul

    2013-02-01

    There have been inconsistencies in the literature regarding asymmetrical neural control and results of experiments using TMS techniques. Therefore, the aim of this study was to further our understanding of the neural relationships that may underlie performance asymmetry with respect to the distal muscles of the hand using a TMS stimulus-response curve technique. Twenty-four male subjects (12 right handed, 12 left handed) participated in a TMS stimulus-response (S-R) curve trial. Focal TMS was applied over the motor cortex to find the optimal position for the first dorsal interossei muscle and to determine rest threshold (RTh). Seven TMS intensities ranging from 90 to 150 % of RTh were delivered in 10 % increments. One single TMS block consisted of 16 stimuli at each intensity. Peak-to-peak amplitudes were measured and the S-R curve generated. In right-handed subjects, the mean difference in slopes between the right and left hand was -0.011 ± 0.03, while the mean difference between hands in left-handed subjects was -0.049 ± 0.08. Left-handed normalized data in right handers displayed a mean of 1.616 ± 1.019 (two-tailed t test p left-handed group showed a significant change in the normalized slope as indicated by a mean of 1.693 ± 0.149 (two-tailed t test p left- and right-handed individuals. However, the results show that the non-dominant motor hemisphere displays a greater amount of excitability than the dominant, which goes against the conventional dogma. This asymmetry indicates that the non-dominant hemisphere may have a higher level of excitation or a lower level of inhibition for both groups of participants.

  19. Gaussian mixture modeling of hemispheric lateralization for language in a large sample of healthy individuals balanced for handedness.

    Directory of Open Access Journals (Sweden)

    Bernard Mazoyer

    Full Text Available Hemispheric lateralization for language production and its relationships with manual preference and manual preference strength were studied in a sample of 297 subjects, including 153 left-handers (LH. A hemispheric functional lateralization index (HFLI for language was derived from fMRI acquired during a covert sentence generation task as compared with a covert word list recitation. The multimodal HFLI distribution was optimally modeled using a mixture of 3 and 4 Gaussian functions in right-handers (RH and LH, respectively. Gaussian function parameters helped to define 3 types of language hemispheric lateralization, namely "Typical" (left hemisphere dominance with clear positive HFLI values, 88% of RH, 78% of LH, "Ambilateral" (no dominant hemisphere with HFLI values close to 0, 12% of RH, 15% of LH and "Strongly-atypical" (right-hemisphere dominance with clear negative HFLI values, 7% of LH. Concordance between dominant hemispheres for hand and for language did not exceed chance level, and most of the association between handedness and language lateralization was explained by the fact that all Strongly-atypical individuals were left-handed. Similarly, most of the relationship between language lateralization and manual preference strength was explained by the fact that Strongly-atypical individuals exhibited a strong preference for their left hand. These results indicate that concordance of hemispheric dominance for hand and for language occurs barely above the chance level, except in a group of rare individuals (less than 1% in the general population who exhibit strong right hemisphere dominance for both language and their preferred hand. They call for a revisit of models hypothesizing common determinants for handedness and for language dominance.

  20. The effect of cognitive load on hemispheric asymmetries in true and false memory.

    Science.gov (United States)

    Tat, Michael J; Azuma, Tamiko

    2016-01-01

    Studies examining hemispheric asymmetries in false memory have shown that the right hemisphere (RH) is more susceptible to false memories compared to the left hemisphere (LH). Theories suggest that hemispheric asymmetries in true and false memory may be due to differences in representational coding and the use of top-down mechanisms in each hemisphere. In the current study, the Deese-Roediger-McDermott false memory paradigm was used in conjunction with divided visual field presentation to examine the role of top-down mechanisms in hemispheric asymmetries of true and false memory. In Experiment 1, participants studied lists of related words while completing secondary cognitive load tasks. In Experiment 2, the secondary tasks were administered during memory retrieval instead of memory encoding. Results revealed that cognitive loads imposed during the study phase influenced veridical memory in the LH more than the RH, but cognitive loads imposed during retrieval did not influence veridical memory in either hemisphere. Surprisingly, false memory rates were not influenced by cognitive loads and were higher in the LH. These data provide evidence that, at least for veridical memory, top-down control mechanisms are used more readily for the encoding of information into memory in the LH compared to the RH.

  1. Left cheek bias for emotion perception, but not expression, is established in children aged 3-7 years.

    Science.gov (United States)

    Lindell, Annukka K; Tenenbaum, Harriet R; Aznar, Ana

    2017-01-01

    As the left hemiface is controlled by the emotion-dominant right hemisphere, emotion is expressed asymmetrically. Portraits showing a model's left cheek consequently appear more emotive. Though the left cheek bias is well established in adults, it has not been investigated in children. To determine whether the left cheek biases for emotion perception and expression are present and/or develop between the ages of 3 and 7 years, 145 children (71 male, 74 female; M age = 65.49 months) completed two experimental tasks: one assessing biases in emotion perception, and the other assessing biases in emotion expression. Regression analysis confirmed that children aged 3-7 years find left cheek portraits happier than right cheek portraits, and age does not predict the magnitude of the bias. In contrast when asked to pose for a photo expressing happiness children did not show a left cheek bias, with logistic regression confirming that age did not predict posing orientations. These findings indicate that though the left cheek bias for emotion perception is established by age 3, a similar bias for emotion expression is not evident by age 7. This implies that tacit knowledge of the left cheek's greater expressivity is not innate but develops in later childhood/adolescence.

  2. Hemispheric asymmetry in the processing of negative and positive words: a divided field study.

    Science.gov (United States)

    Holtgraves, Thomas; Felton, Adam

    2011-06-01

    Research on the lateralisation of brain functions for emotion has yielded different results as a function of whether it is the experience, expression, or perceptual processing of emotion that is examined. Further, for the perception of emotion there appear to be differences between the processing of verbal and nonverbal stimuli. The present research examined the hemispheric asymmetry in the processing of verbal stimuli varying in emotional valence. Participants performed a lexical decision task for words varying in affective valence (but equated in terms of arousal) that were presented briefly to the right or left visual field. Participants were significantly faster at recognising positive words presented to the right visual field/left hemisphere. This pattern did not occur for negative words (and was reversed for high arousal negative words). These results suggest that the processing of verbal stimuli varying in emotional valence tends to parallel hemispheric asymmetry in the experience of emotion.

  3. Effects of hemisphere speech dominance and seizure focus on patterns of behavioral response errors for three types of stimuli.

    Science.gov (United States)

    Rausch, R; MacDonald, K

    1997-03-01

    We used a protocol consisting of a continuous presentation of stimuli with associated response requests during an intracarotid sodium amobarbital procedure (IAP) to study the effects of hemisphere injected (speech dominant vs. nondominant) and seizure focus (left temporal lobe vs. right temporal lobe) on the pattern of behavioral response errors for three types of visual stimuli (pictures of common objects, words, and abstract forms). Injection of the left speech dominant hemisphere compared to the right nondominant hemisphere increased overall errors and affected the pattern of behavioral errors. The presence of a seizure focus in the contralateral hemisphere increased overall errors, particularly for the right temporal lobe seizure patients, but did not affect the pattern of behavioral errors. Left hemisphere injections disrupted both naming and reading responses at a rate similar to that of matching-to-sample performance. Also, a short-term memory deficit was observed with all three stimuli. Long-term memory testing following the left hemisphere injection indicated that only for pictures of common objects were there fewer errors during the early postinjection period than for the later long-term memory testing. Therefore, despite the inability to respond to picture stimuli, picture items, but not words or forms, could be sufficiently encoded for later recall. In contrast, right hemisphere injections resulted in few errors, with a pattern suggesting a mild general cognitive decrease. A selective weakness in learning unfamiliar forms was found. Our findings indicate that different patterns of behavioral deficits occur following the left vs. right hemisphere injections, with selective patterns specific to stimulus type.

  4. Optimization of a scintillation detector with hemispherical configuration

    International Nuclear Information System (INIS)

    Saules Mendonca, A.C. de.

    1980-08-01

    A hemispherical configuration for scintillation detectors, is introduced so as to minimize the dispersion in light collection by reducing the number of reflexions. Better results in the process of light collection appear explicitly in the gain in the amplitude of the pulse and a better resolution in time and energy when a comparative analysis is made between the cylindrical and hemispherical geometries. The measurements were made using NE102, a plastic scintillator with cylindrical and hemispherical forms, comparing the results of pulse amplitude and energy resolution. The results were quite significant showing a 13% improvement in pulse amplitude and more than 10% in energy resolution for some values of energies from 511 KeV to 1275 KeV. (Author) [pt

  5. Modeling and verification of hemispherical solar still using ANSYS CFD

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Hitesh N. [KSV University, Gujarat Power Engineering and Research Institute, Mehsana (India); Shah, P.K. [Silver Oak College of Engineering and Technology, Ahmedabad, Gujarat (India)

    2013-07-01

    In every efficient solar still design, water temperature, vapor temperature and distillate output, and difference between water temperature and inner glass cover temperatures are very important. Here, two dimensional three phase model of hemispherical solar still is made for evaporation as well as condensation process in ANSYS CFD. Simulation results like water temperature, vapor temperature, distillate output compared with actual experimental results of climate conditions of Mehsana (latitude of 23° 59’ and longitude of 72° 38) of hemispherical solar still. Water temperature and distillate output were good agreement with actual experimental results. Study shows that ANSYS-CFD is very powerful as well as efficient tool for design, comparison purpose of hemispherical solar still.

  6. An ERP assessment of hemispheric projections in foveal and extrafoveal word recognition.

    Directory of Open Access Journals (Sweden)

    Timothy R Jordan

    Full Text Available BACKGROUND: The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality. METHODOLOGY: Single words (and pseudowords were presented to the left or right of fixation, entirely within either foveal or extrafoveal vision. To maximize the likelihood of unilateral projections for foveal displays, stimuli in foveal vision were presented away from the midline. The processing of stimuli in each location was assessed by combining behavioural measures (reaction times, accuracy with on-line monitoring of hemispheric activity using event-related potentials recorded over each hemisphere, and carefully-controlled presentation procedures using an eye-tracker linked to a fixation-contingent display. PRINCIPAL FINDINGS: Event-related potentials 100-150 ms and 150-200 ms after stimulus onset indicated that stimuli in extrafoveal and foveal locations were projected unilaterally to the hemisphere contralateral to the presentation hemifield with no concurrent projection to the ipsilateral hemisphere. These effects were similar for words and pseudowords, suggesting this early division occurred before word recognition. Indeed, event-related potentials revealed differences between words and pseudowords 300-350 ms after stimulus onset, for foveal and extrafoveal locations, indicating that word recognition had now occurred. However, these later event-related potentials also revealed that the hemispheric division observed previously was no longer present for foveal locations but remained for extrafoveal locations. These findings closely matched the behavioural finding that foveal locations produced similar performance each side of fixation but extrafoveal locations produced left-right asymmetries. CONCLUSIONS: These findings indicate that an initial division in unilateral hemispheric projections occurs in

  7. An ERP Assessment of Hemispheric Projections in Foveal and Extrafoveal Word Recognition

    Science.gov (United States)

    Jordan, Timothy R.; Fuggetta, Giorgio; Paterson, Kevin B.; Kurtev, Stoyan; Xu, Mengyun

    2011-01-01

    Background The existence and function of unilateral hemispheric projections within foveal vision may substantially affect foveal word recognition. The purpose of this research was to reveal these projections and determine their functionality. Methodology Single words (and pseudowords) were presented to the left or right of fixation, entirely within either foveal or extrafoveal vision. To maximize the likelihood of unilateral projections for foveal displays, stimuli in foveal vision were presented away from the midline. The processing of stimuli in each location was assessed by combining behavioural measures (reaction times, accuracy) with on-line monitoring of hemispheric activity using event-related potentials recorded over each hemisphere, and carefully-controlled presentation procedures using an eye-tracker linked to a fixation-contingent display. Principal Findings Event-related potentials 100–150 ms and 150–200 ms after stimulus onset indicated that stimuli in extrafoveal and foveal locations were projected unilaterally to the hemisphere contralateral to the presentation hemifield with no concurrent projection to the ipsilateral hemisphere. These effects were similar for words and pseudowords, suggesting this early division occurred before word recognition. Indeed, event-related potentials revealed differences between words and pseudowords 300–350 ms after stimulus onset, for foveal and extrafoveal locations, indicating that word recognition had now occurred. However, these later event-related potentials also revealed that the hemispheric division observed previously was no longer present for foveal locations but remained for extrafoveal locations. These findings closely matched the behavioural finding that foveal locations produced similar performance each side of fixation but extrafoveal locations produced left-right asymmetries. Conclusions These findings indicate that an initial division in unilateral hemispheric projections occurs in foveal vision

  8. Transcortical mixed aphasia due to cerebral infarction in left inferior frontal lobe and temporo-parietal lobe

    International Nuclear Information System (INIS)

    Maeshima, S.; Matsumoto, T.; Ueyoshi, A.; Toshiro, H.; Sekiguchi, E.; Okita, R.; Yamaga, H.; Ozaki, F.; Moriwaki, H.; Roger, P.

    2002-01-01

    We present a case of transcortical mixed aphasia caused by a cerebral embolism. A 77-year-old right-handed man was admitted to our hospital with speech disturbance and a right hemianopia. His spontaneous speech was remarkably reduced, and object naming, word fluency, comprehension, reading and writing were all severely disturbed. However, repetition of phonemes and sentences and reading aloud were fully preserved. Although magnetic resonance imaging (MRI) showed cerebral infarcts in the left frontal and parieto-occipital lobe which included the inferior frontal gyrus and angular gyrus, single photon emission CT revealed a wider area of low perfusion over the entire left hemisphere except for part of the left perisylvian language areas. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. Hence, it appears that transcortical mixed aphasia may be caused by the isolation of perisylvian speech areas, even if there is a lesion in the inferior frontal gyrus, due to disconnection from surrounding areas. (orig.)

  9. Transcortical mixed aphasia due to cerebral infarction in left inferior frontal lobe and temporo-parietal lobe

    Energy Technology Data Exchange (ETDEWEB)

    Maeshima, S.; Matsumoto, T.; Ueyoshi, A. [Department of Physical Medicine and Rehabilitation, Wakayama Medical University, Wakayama (Japan); Toshiro, H.; Sekiguchi, E.; Okita, R.; Yamaga, H.; Ozaki, F.; Moriwaki, H. [Department of Neurological Surgery, Hidaka General Hospital, Wakayama (Japan); Roger, P. [School of Communication Sciences and Disorders, University of Sydney, Sydney, NSW (Australia)

    2002-02-01

    We present a case of transcortical mixed aphasia caused by a cerebral embolism. A 77-year-old right-handed man was admitted to our hospital with speech disturbance and a right hemianopia. His spontaneous speech was remarkably reduced, and object naming, word fluency, comprehension, reading and writing were all severely disturbed. However, repetition of phonemes and sentences and reading aloud were fully preserved. Although magnetic resonance imaging (MRI) showed cerebral infarcts in the left frontal and parieto-occipital lobe which included the inferior frontal gyrus and angular gyrus, single photon emission CT revealed a wider area of low perfusion over the entire left hemisphere except for part of the left perisylvian language areas. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. Hence, it appears that transcortical mixed aphasia may be caused by the isolation of perisylvian speech areas, even if there is a lesion in the inferior frontal gyrus, due to disconnection from surrounding areas. (orig.)

  10. Cerebral Hemispheric Lateralization Associated with Hippocampal Sclerosis May Affect Interictal Cardiovascular Autonomic Functions in Temporal Lobe Epilepsy

    Directory of Open Access Journals (Sweden)

    Rokia Ghchime

    2016-01-01

    Full Text Available It is well established that the temporal lobe epilepsy (TLE is linked to the autonomic nervous system dysfunctions. Seizures alter the function of different systems such as the respiratory, cardiovascular, gastrointestinal, and urogenital systems. The aim of this work was to evaluate the possible factors which may be involved in interictal cardiovascular autonomic function in temporal lobe epilepsy with complex partial seizures, and with particular attention to hippocampal sclerosis. The study was conducted in 30 patients with intractable temporal lobe epilepsy (19 with left hippocampal sclerosis, 11 with right hippocampal sclerosis. All subjects underwent four tests of cardiac autonomic function: heart rate changes in response to deep breathing, heart rate, and blood pressure variations throughout resting activity and during hand grip, mental stress, and orthostatic tests. Our results show that the right cerebral hemisphere predominantly modulates sympathetic activity, while the left cerebral hemisphere mainly modulates parasympathetic activity, which mediated tachycardia and excessive bradycardia counterregulation, both of which might be involved as a mechanism of sudden unexpected death in epilepsy patients (SUDEP.

  11. Functional Hemispheric (Asymmetries in the Aged Brain—Relevance for Working Memory

    Directory of Open Access Journals (Sweden)

    Madalena Esteves

    2018-03-01

    Full Text Available Functional hemispheric asymmetries have been described in different cognitive processes, such as decision-making and motivation. Variations in the pattern of left/right activity have been associated with normal brain functioning, and with neuropsychiatric diseases. Such asymmetries in brain activity evolve throughout life and are thought to decrease with aging, but clear associations with cognitive function have never been established. Herein, we assessed functional laterality during a working memory task (N-Back in a healthy aging cohort (over 50 years old and associated these asymmetries with performance in the test. Activity of lobule VI of the cerebellar hemisphere and angular gyrus was found to be lateralized to the right hemisphere, while the precentral gyrus presented left > right activation during this task. Interestingly, 1-Back accuracy was positively correlated with left > right superior parietal lobule activation, which was mostly due to the influence of the left hemisphere. In conclusion, although regions were mostly symmetrically activated during the N-Back task, performance in working memory in aged individuals seems to benefit from lateralized involvement of the superior parietal lobule.

  12. Brain processing of consonance/dissonance in musicians and controls: a hemispheric asymmetry revisited.

    Science.gov (United States)

    Proverbio, Alice Mado; Orlandi, Andrea; Pisanu, Francesca

    2016-09-01

    It was investigated to what extent musical expertise influences the auditory processing of harmonicity by recording event-related potentials. Thirty-four participants (18 musicians and 16 controls) were asked to listen to hundreds of chords, differing in their degree of consonance, their complexity (from two to six composing sounds) and their range (distance of two adjacent pitches, from quartertones to more than 18 semitone steps). The task consisted of detecting rare targets. An early auditory N1 was observed that was modulated by chord dissonance in both groups. The response was generated in the right medial temporal gyrus (MTG) for consonant chords but in the left MTG for dissonant chords according to swLORETA reconstruction performed. An anterior negativity (N2) was enhanced only in musicians in response to chords featuring quartertones, thus suggesting a greater pitch sensitivity for simultaneous pure tones in the skilled brain. The P300 was affected by the frequency range only in musicians, who also showed a greater sensitivity to sound complexity. A strong left hemispheric specialization for processing quartertones in the left temporal cortex of musicians was observed at N2 level (250-350 ms), which was observed on the right side in controls. Additionally, in controls, widespread activity of the right limbic area was associated with listening to close frequencies causing disturbing beats, possibly suggesting a negative aesthetic appreciation for these stimuli. Overall, the data show a finer and more tuned neural representation of pitch intervals in musicians, linked to a marked specialization of their left temporal cortex (BA21/38). © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  13. Non-compact left ventricle/hypertrabeculated left ventricle

    International Nuclear Information System (INIS)

    Restrepo, Gustavo; Castano, Rafael; Marmol, Alejandro

    2005-01-01

    Non-compact left ventricle/hypertrabeculated left ventricle is a myocardiopatie produced by an arrest of the normal left ventricular compaction process during the early embryogenesis. It is associated to cardiac anomalies (congenital cardiopaties) as well as to extracardial conditions (neurological, facial, hematologic, cutaneous, skeletal and endocrinological anomalies). This entity is frequently unnoticed, being diagnosed only in centers with great experience in the diagnosis and treatment of myocardiopathies. Many cases of non-compact left ventricle have been initially misdiagnosed as hypertrophic myocardiopatie, endocardial fibroelastosis, dilated cardiomyopatie, restrictive cardiomyopathy and endocardial fibrosis. It is reported the case of a 74 years old man with a history of chronic arterial hypertension and diabetes mellitus, prechordial chest pain and mild dyspnoea. An echocardiogram showed signs of non-compact left ventricle with prominent trabeculations and deep inter-trabecular recesses involving left ventricular apical segment and extending to the lateral and inferior walls. Literature on this topic is reviewed

  14. Praxial disorders in focal lesions of cerebral hemispheres

    Directory of Open Access Journals (Sweden)

    Jorge Murillo Duran

    2007-11-01

    Full Text Available The purpose of this work is to analyze paraxial difficulties i.e, functional disorders in movementresulting from cerebral tissue lesions. In accordance with the literature on the subject, the following definition, the following definition of apraxia has been accepted: “Apraxia is inability in properly executing kinetic tasks without impairment or loss of motor or sensory functions or ataxia with would condition such inability”. “Proper execution” used in this definition concerns not only the effect of the action but also means of its realization. “Kinetic tasks” signify all aspects of motor activity defined by instructions, irrespective of the type of instruction (verbal or gestures, and regardless of whether it required −in the final effect− imitating the movement of the investigator or whether they were performed independently. The methodology has been based in the principle on Luria’s works.Deliberations on praxial disorders were based on investigation results embracing 90 patients with focal cerebral lesions. In fifty cases, changes were localized in the left cerebral hemisphere, in forty cases−in the right hemisphere. The summing up the results concerning a global comparison between cerebral hemispheres, indicate the following regularities: Results achieved made it possible to form the opinion that not all of the generally accepted tests investigating praxia in persons with cerebral lesions are solved faultlessly by healthy individuals; thus, a faulty execution should not always be regarded as a sign of pathological functioning of the cerebral tissue as a result of lesion.

  15. CMB-S4 and the hemispherical variance anomaly

    Science.gov (United States)

    O'Dwyer, Márcio; Copi, Craig J.; Knox, Lloyd; Starkman, Glenn D.

    2017-09-01

    Cosmic microwave background (CMB) full-sky temperature data show a hemispherical asymmetry in power nearly aligned with the Ecliptic. In real space, this anomaly can be quantified by the temperature variance in the Northern and Southern Ecliptic hemispheres, with the Northern hemisphere displaying an anomalously low variance while the Southern hemisphere appears unremarkable [consistent with expectations from the best-fitting theory, Lambda Cold Dark Matter (ΛCDM)]. While this is a well-established result in temperature, the low signal-to-noise ratio in current polarization data prevents a similar comparison. This will change with a proposed ground-based CMB experiment, CMB-S4. With that in mind, we generate realizations of polarization maps constrained by the temperature data and predict the distribution of the hemispherical variance in polarization considering two different sky coverage scenarios possible in CMB-S4: full Ecliptic north coverage and just the portion of the North that can be observed from a ground-based telescope at the high Chilean Atacama plateau. We find that even in the set of realizations constrained by the temperature data, the low Northern hemisphere variance observed in temperature is not expected in polarization. Therefore, observing an anomalously low variance in polarization would make the hypothesis that the temperature anomaly is simply a statistical fluke more unlikely and thus increase the motivation for physical explanations. We show, within ΛCDM, how variance measurements in both sky coverage scenarios are related. We find that the variance makes for a good statistic in cases where the sky coverage is limited, however, full northern coverage is still preferable.

  16. optical analysis of a hemispheric concentrator with a manual ...

    African Journals Online (AJOL)

    PROF. BARTH EKWEME

    sophisticated system involving robotics, managed by a. PLC using algorithms of calculation for the orientation of each element is necessary. Studies on hemispheric concentrators were conducted, usually to show that they focus at a point just like a paraboloid concentrator (Bellel, 2011). The angle change does not cause a ...

  17. Paleoceanography. Antarctic role in Northern Hemisphere glaciation.

    Science.gov (United States)

    Woodard, Stella C; Rosenthal, Yair; Miller, Kenneth G; Wright, James D; Chiu, Beverly K; Lawrence, Kira T

    2014-11-14

    Earth's climate underwent a major transition from the warmth of the late Pliocene, when global surface temperatures were ~2° to 3°C higher than today, to extensive Northern Hemisphere glaciation (NHG) ~2.73 million years ago (Ma). We show that North Pacific deep waters were substantially colder (4°C) and probably fresher than the North Atlantic Deep Water before the intensification of NHG. At ~2.73 Ma, the Atlantic-Pacific temperature gradient was reduced to <1°C, suggesting the initiation of stronger heat transfer from the North Atlantic to the deep Pacific. We posit that increased glaciation of Antarctica, deduced from the 21 ± 10-meter sea-level fall from 3.15 to 2.75 Ma, and the development of a strong polar halocline fundamentally altered deep ocean circulation, which enhanced interhemispheric heat and salt transport, thereby contributing to NHG. Copyright © 2014, American Association for the Advancement of Science.

  18. Visual attention capacity after right hemisphere lesions

    DEFF Research Database (Denmark)

    Habekost, Thomas; Rostrup, Egill

    2007-01-01

    for both VSTM capacity and ipsilesional processing speed. The study also showed that lesions in a large region of the right hemisphere, including the putamen, insula, and inferior frontal cortex, do not lead to general deficits in the capacity of visual attention. Udgivelsesdato: 2007-Apr-8......Recently there has been a growing interest in visual short-term memory (VSTM) including the neural basis of the function. Processing speed, another main aspect of visual attention capacity, has received less investigation. For both cognitive functions human lesion studies are sparse. We used...... a whole report experiment for estimation of these two parameters in 22 patients with right side stroke. Psychophysical performance was analyzed using Bundesen's [Bundesen, C. (1990). A theory of visual attention. Psychological Review, 97, 523-547] Theory of Visual Attention (TVA) and compared...

  19. Visual attention capacity after right hemisphere lesions

    DEFF Research Database (Denmark)

    Habekost, Thomas; Rostrup, Egill

    2007-01-01

    Recently there has been a growing interest in visual short-term memory (VSTM) including the neural basis of the function. Processing speed, another main aspect of visual attention capacity, has received less investigation. For both cognitive functions human lesion studies are sparse. We used...... a whole report experiment for estimation of these two parameters in 22 patients with right side stroke. Psychophysical performance was analyzed using Bundesen's [Bundesen, C. (1990). A theory of visual attention. Psychological Review, 97, 523-547] Theory of Visual Attention (TVA) and compared...... for both VSTM capacity and ipsilesional processing speed. The study also showed that lesions in a large region of the right hemisphere, including the putamen, insula, and inferior frontal cortex, do not lead to general deficits in the capacity of visual attention. Udgivelsesdato: 2007-Apr-8...

  20. Communication Impairments in Patients with Right Hemisphere Damage

    Directory of Open Access Journals (Sweden)

    Abusamra, Valeria

    2009-06-01

    Full Text Available Right brain damages can manifest deficits of communicative skills, which sometimes cause an important inability.The communication impairments following a right hemisphere damage are distinct from those in aphasia and may affect discursive, lexico-semantic, pragmatic, and prosodic components of communication. It is calculated that this troubles affect almost a 50% of this patients.However, these impairments have essentially been studied separately and their possible coexistence in a same individual is still unknown. Moreover, the clinical profiles of communication impairments following a right hemisphere damage, including their correlation with underlying cognitive deficits, are still unreported. The goal of this article is to offer an overview of the verbal communication deficits that can be found in right-hemisphere-damaged individuals. These deficits can interfere, at different levels, with prosody, the semantic processing of words and discourse and pragmatic abilities. In spite of the incapability that they produce, communicational impairments in right brain damaged are usually neglected. Probably, the sub-diagnostic is due to the lack of an appropriate classification or to the absent of adequate assessment tools. In fact, patients with right brain damages might present harsh communicational deficits but perform correctly on aphasia tests because the last ones are not designed to detect this kind of deficit but left brain damaged impairments. Increasing our knowledge about the role of the right-hemisphere in verbal communication will have major theoretical and clinical impacts; it could facilitate the diagnosis of right brain patients in the clinical circle and it will help to lay the foundations to elaborate methods and strategies of intervention.

  1. Hemispheric Division of Labour in Reading

    Science.gov (United States)

    Shillcock, Richard C.; McDonald, Scott A.

    2005-01-01

    We argue that the reading of words and text is fundamentally conditioned by the splitting of the fovea and the hemispheric division of the brain, and, furthermore, that the equitable division of labour between the hemispheres is a characteristic of normal visual word recognition. We report analyses of a representative corpus of the eye fixations…

  2. Microsurgical efficacy and safety of a right-hemispheric approach for unruptured anterior communicating artery aneurysms.

    Science.gov (United States)

    Kim, So Yeon; Jeon, Hong Jun; Ihm, Eun Hyun; Park, Keun Young; Lee, Jae Whan; Huh, Seung Kon

    2015-10-01

    We investigated the effectiveness of a right hemispheric surgical approach in treating unruptured anterior communicating artery aneurysms. Between January 2005 and June 2012, 305 patients with anterior communicating artery (Acom) aneurysms were treated using the pterional approach. Among them, 113 who underwent microsurgery with an unruptured Acom aneurysm were enrolled in this study. Every patient was evaluated with digital subtraction angiography preoperatively and CT scans were taken several times postoperatively. Surgical outcomes and complications were evaluated at discharge using the Glasgow Outcome Scale and at 6 months after surgery with CT angiography. Enrolled patients included 55 males and 58 females with a mean age of 56.3 years (range: 30-75 years). The mean diameter of the aneurysm was 5.8mm (range: 1.9-24.1). Left A1 dominancy was found in 71 patients (62.8%) whereas right A1 dominancy was found in 20 patients (17.7%), and right pterional craniotomies were performed in 92 patients (81.4%) while left pterional craniotomies were performed in 21 patients (18.6%). Complete clip application was achieved in 94.9% of patients (74 of 78) in right-side approach group but in only 81.3% of patients (13 of 16) in left-side approach group. Despite a left A1 dominancy and approached from the right, more than 90% of the patients had an excellent outcome at discharge (GOS 5) and more than 90% a complete aneurysm clipping at the 6-month follow-up CT angiography although it was not statistically significant. Microsurgical clipping of the unruptured Acom aneurysm through a right-side surgical approach showed favorable postoperative clinical and anatomical outcomes, especially aneurysms smaller than 10mm. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Brain Stimulation and the Role of the Right Hemisphere in Aphasia Recovery.

    Science.gov (United States)

    Turkeltaub, Peter E

    2015-11-01

    Aphasia is a common consequence of left hemisphere stroke and causes a disabling loss of language and communication ability. Current treatments for aphasia are inadequate, leaving a majority of aphasia sufferers with ongoing communication difficulties for the rest of their lives. In the past decade, two forms of noninvasive brain stimulation, repetitive transcranial magnetic stimulation and transcranial direct current stimulation, have emerged as promising new treatments for aphasia. The most common brain stimulation protocols attempt to inhibit the intact right hemisphere based on the hypothesis that maladaptive activity in the right hemisphere limits language recovery in the left. There is now sufficient evidence to demonstrate that this approach, at least for repetitive transcranial magnetic stimulation, improves specific language abilities in aphasia. However, the biological mechanisms that produce these behavioral improvements remain poorly understood. Taken in the context of the larger neurobiological literature on aphasia recovery, the role of the right hemisphere in aphasia recovery remains unclear. Additional research is needed to understand biological mechanisms of recovery, in order to optimize brain stimulation treatments for aphasia. This article summarizes the current evidence on noninvasive brain stimulation methods for aphasia and the neuroscientific considerations surrounding treatments using right hemisphere inhibition. Suggestions are provided for further investigation and for clinicians whose patients ask about brain stimulation treatments for aphasia.

  4. The language of arithmetic across the hemispheres: An event-related potential investigation.

    Science.gov (United States)

    Dickson, Danielle S; Federmeier, Kara D

    2017-05-01

    Arithmetic expressions, like verbal sentences, incrementally lead readers to anticipate potential appropriate completions. Existing work in the language domain has helped us understand how the two hemispheres differently participate in and contribute to the cognitive process of sentence reading, but comparatively little work has been done with mathematical equation processing. In this study, we address this gap by examining the ERP response to provided answers to simple multiplication problems, which varied both in levels of correctness (given an equation context) and in visual field of presentation (joint attention in central presentation, or biased processing to the left or right hemisphere through contralateral visual field presentation). When answers were presented to any of the visual fields (hemispheres), there was an effect of correctness prior to the traditional N400 timewindow, which we interpret as a P300 in response to a detected target item (the correct answer). In addition to this response, equation answers also elicited a late positive complex (LPC) for incorrect answers. Notably, this LPC effect was most prominent in the left visual field (right hemisphere), and it was also sensitive to the confusability of the wrong answer - incorrect answers that were closely related to the correct answer elicited a smaller LPC. This suggests a special, prolonged role for the right hemisphere during answer evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. HEMISPHERIC CENTER FOR ENVIRONMENTAL TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Ebadian

    1999-10-31

    The Deactivation and Decommissioning (D&D) Technology Assessment Program (TAP) was developed to provide detailed, comparable data for environmental technologies and to disseminate this data to D&D professionals in a manner that will facilitate the review and selection of technologies to perform decontamination and decommissioning. The objectives for this project include the following: Determine technology needs through review of the Site Technology Coordination Group (STCG) information and other applicable websites and needs databases; Perform a detailed review of industries that perform similar activities as those required in D&D operations to identify additional technologies; Define the technology assessment program for characterization and waste management problem sets; Define the data management program for characterization, dismantlement, and waste management problem sets; Evaluate baseline and innovative technologies under standard test conditions at Florida International University's Hemispheric Center for Environmental Technology (FIU-HCET) and other locations and collect data in the areas of performance, cost, health and safety, operations and maintenance, and primary and secondary waste generation; Continue to locate, verify, and incorporate technology performance data from other sources into the multimedia information system; and Develop the conceptual design for a dismantlement technology decision analysis tool for dismantlement technologies.

  6. Face gender categorization and hemispheric asymmetries: Contrasting evidence from connected and disconnected brains.

    Science.gov (United States)

    Prete, Giulia; Fabri, Mara; Foschi, Nicoletta; Tommasi, Luca

    2016-12-17

    We investigated hemispheric asymmetries in categorization of face gender by means of a divided visual field paradigm, in which female and male faces were presented unilaterally for 150ms each. A group of 60 healthy participants (30 males) and a male split-brain patient (D.D.C.) were asked to categorize the gender of the stimuli. Healthy participants categorized male faces presented in the right visual field (RVF) better and faster than when presented in the left visual field (LVF), and female faces presented in the LVF than in the RVF, independently of the participants' sex. Surprisingly, the recognition rates of D.D.C. were at chance levels - and significantly lower than those of the healthy participants - for both female and male faces presented in the RVF, as well as for female faces presented in the LVF. His performance was higher than expected by chance - and did not differ from controls - only for male faces presented in the LVF. The residual right-hemispheric ability of the split-brain patient in categorizing male faces reveals an own-gender bias lateralized in the right hemisphere, in line with the rightward own-identity and own-age bias previously shown in split-brain patients. The gender-contingent hemispheric dominance found in healthy participants confirms the previously shown right-hemispheric superiority in recognizing female faces, and also reveals a left-hemispheric superiority in recognizing male faces, adding an important evidence of hemispheric imbalance in the field of face and gender perception. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Reducing chronic visuo-spatial neglect following right hemisphere stroke through instrument playing

    Directory of Open Access Journals (Sweden)

    Rebeka eBodak

    2014-06-01

    Full Text Available Unilateral visuo-spatial neglect is a neuropsychological syndrome commonly resulting from right hemisphere strokes at the temporo-parietal junction of the infero-posterior parietal cortex. Neglect is characterised by reduced awareness of stimuli presented on patients’ contralesional side of space and has previously been shown to be improved by a number of motivational influences, including listening to preferred music and numerical sequence completion. Here we examined whether playing musical sequences on chime bars – an instrument with a horizontal alignment – would bring about clinically significant improvement in chronic neglect.Two left neglect patients completed an intervention comprising four weekly 30-minute music sessions involving playing scales and familiar melodies on chime bars from right to left. Two cancellation tests (Mesulam shape, BIT star, the line bisection test, and the neglect subtest from the computerised TAP (Test for Attentional Performance battery were administered three times during a preliminary baseline phase, before and after each music session during the rehabilitation phase to investigate short-term effects, as well as one week after the last intervention session to investigate whether any effects would persist.Both patients demonstrated significant short-term and longer-lasting improvements on the Mesulam shape cancellation test. One patient also showed longer-lasting effects on the BIT star cancellation test and scored in the normal range one week after the intervention. These findings provide preliminary evidence that active music-making may help neglect patients attend more to their affected side.

  8. Multigene Phylogeography of Bactrocera caudata (Insecta: Tephritidae): Distinct Genetic Lineages in Northern and Southern Hemispheres.

    Science.gov (United States)

    Yong, Hoi-Sen; Lim, Phaik-Eem; Tan, Ji; Song, Sze-Looi; Suana, I Wayan; Eamsobhana, Praphathip

    2015-01-01

    Bactrocera caudata is a pest of pumpkin flower. Specimens of B. caudata from the northern hemisphere (mainland Asia) and southern hemisphere (Indonesia) were analysed using the partial DNA sequences of the nuclear 28S rRNA and internal transcribed spacer region 2 (ITS-2) genes, and the mitochondrial cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit II (COII) and 16S rRNA genes. The COI, COII, 16S rDNA and concatenated COI+COII+16S and COI+COII+16S+28S+ITS-2 nucleotide sequences revealed that B. caudata from the northern hemisphere (Peninsular Malaysia, East Malaysia, Thailand) was distinctly different from the southern hemisphere (Indonesia: Java, Bali and Lombok), without common haplotype between them. Phylogenetic analysis revealed two distinct clades (northern and southern hemispheres), indicating distinct genetic lineage. The uncorrected 'p' distance for the concatenated COI+COII+16S nucleotide sequences between the taxa from the northern and southern hemispheres ('p' = 4.46-4.94%) was several folds higher than the 'p' distance for the taxa in the northern hemisphere ('p' = 0.00-0.77%) and the southern hemisphere ('p' = 0.00%). This distinct difference was also reflected by concatenated COI+COII+16S+28S+ITS-2 nucleotide sequences with an uncorrected 'p' distance of 2.34-2.69% between the taxa of northern and southern hemispheres. In accordance with the type locality the Indonesian taxa belong to the nominal species. Thus the taxa from the northern hemisphere, if they were to constitute a cryptic species of the B. caudata species complex based on molecular data, need to be formally described as a new species. The Thailand and Malaysian B. caudata populations in the northern hemisphere showed distinct genetic structure and phylogeographic pattern.

  9. Fluctuations of Induced Charge in Hemispherical Detectors

    Science.gov (United States)

    Samedov, V. V.

    2017-12-01

    Detectors with hemispherical geometry are used to eliminate the contribution from the hole component to the signal of a detector based on a compound semiconductor operating at room temperature. In this work, the random process of charge induction on electrodes of a detector with hemispherical geometry is theoretically considered with allowance for capture of electrons by traps. Formulas are obtained for the first two moments of the distribution function for the induced charge on the detector electrodes. These formulas help analyze the contribution of the electron transport in detectors with hemispherical geometry.

  10. Cross-hemispheric dopamine projections have functional significance

    Science.gov (United States)

    Fox, Megan E.; Mikhailova, Maria A.; Bass, Caroline E.; Takmakov, Pavel; Gainetdinov, Raul R.; Budygin, Evgeny A.; Wightman, R. Mark

    2016-01-01

    Dopamine signaling occurs on a subsecond timescale, and its dysregulation is implicated in pathologies ranging from drug addiction to Parkinson’s disease. Anatomic evidence suggests that some dopamine neurons have cross-hemispheric projections, but the significance of these projections is unknown. Here we report unprecedented interhemispheric communication in the midbrain dopamine system of awake and anesthetized rats. In the anesthetized rats, optogenetic and electrical stimulation of dopamine cells elicited physiologically relevant dopamine release in the contralateral striatum. Contralateral release differed between the dorsal and ventral striatum owing to differential regulation by D2-like receptors. In the freely moving animals, simultaneous bilateral measurements revealed that dopamine release synchronizes between hemispheres and intact, contralateral projections can release dopamine in the midbrain of 6-hydroxydopamine–lesioned rats. These experiments are the first, to our knowledge, to show cross-hemispheric synchronicity in dopamine signaling and support a functional role for contralateral projections. In addition, our data reveal that psychostimulants, such as amphetamine, promote the coupling of dopamine transients between hemispheres. PMID:27298371

  11. Satellite Global and Hemispheric Lower Tropospheric Temperature Annual Temperature Cycle

    Directory of Open Access Journals (Sweden)

    Michael A. Brunke

    2010-11-01

    Full Text Available Previous analyses of the Earth’s annual cycle and its trends have utilized surface temperature data sets. Here we introduce a new analysis of the global and hemispheric annual cycle using a satellite remote sensing derived data set during the period 1979–2009, as determined from the lower tropospheric (LT channel of the MSU satellite. While the surface annual cycle is tied directly to the heating and cooling of the land areas, the tropospheric annual cycle involves additionally the gain or loss of heat between the surface and atmosphere. The peak in the global tropospheric temperature in the 30 year period occurs on 10 July and the minimum on 9 February in response to the larger land mass in the Northern Hemisphere. The actual dates of the hemispheric maxima and minima are a complex function of many variables which can change from year to year thereby altering these dates.Here we examine the time of occurrence of the global and hemispheric maxima and minima lower tropospheric temperatures, the values of the annual maxima and minima, and the slopes and significance of the changes in these metrics.  The statistically significant trends are all relatively small. The values of the global annual maximum and minimum showed a small, but significant trend. Northern and Southern Hemisphere maxima and minima show a slight trend toward occurring later in the year. Most recent analyses of trends in the global annual cycle using observed surface data have indicated a trend toward earlier maxima and minima.

  12. Increased gray matter volume of left pars opercularis in male orchestral musicians correlate positively with years of musical performance.

    Science.gov (United States)

    Abdul-Kareem, Ihssan A; Stancak, Andrej; Parkes, Laura M; Sluming, Vanessa

    2011-01-01

    To compare manual volumetry of gray matter (GM) / white matter (WM) of Broca's area subparts: pars opercularis (POP) and pars triangularis (PTR) in both hemispheres between musicians and nonmusician, as it has been shown that these regions are crucial for musical abilities. A previous voxel-based morphometric (VBM) study conducted in our laboratory reported increased GM density in Broca's area of left hemisphere in male orchestral musicians. Functional segregation of POP/PTR justified separate volumetric analysis of these parts. We used the same cohort for the VBM study. Manual morphometry (stereology) was used to compare volumes between 26/26 right-handed orchestral musicians/nonmusicians. As expected, musicians showed significantly increased GM volume in the Broca's area, specifically in the left POP. No significant results were detected in right POP, left/right PTR GM volumes, and WM volumes for all regions. Results were positively correlated with years of musical performance (r = 0.7, P = 0.0001). This result corroborates the VBM study and is in line with the hypothesis of critical involvement of POP in hearing-action integration being an integral component of frontoparietotemporal mirror neuron network. We hypothesize that increased size of musicians' left POP represent use-dependent structural adaptation in response to intensive audiomotor skill acquisition. Copyright © 2010 Wiley-Liss, Inc.

  13. The left visual-field advantage in rapid visual presentation is amplified rather than reduced by posterior-parietal rTMS

    DEFF Research Database (Denmark)

    Verleger, Rolf; Möller, Friderike; Kuniecki, Michal

    2010-01-01

    In the present task, series of visual stimuli are rapidly presented left and right, containing two target stimuli, T1 and T2. In previous studies, T2 was better identified in the left than in the right visual field. This advantage of the left visual field might reflect dominance exerted...... by the right over the left hemisphere. If so, then repetitive transcranial magnetic stimulation (rTMS) to the right parietal cortex might release the left hemisphere from right-hemispheric control, thereby improving T2 identification in the right visual field. Alternatively or additionally, the asymmetry in T2......) either as effective or as sham stimulation. In two experiments, either one of these two factors, hemisphere and effectiveness of rTMS, was varied within or between participants. Again, T2 was much better identified in the left than in the right visual field. This advantage of the left visual field...

  14. Commentary: Left Hand, Right Hand and on the Other Hand

    Science.gov (United States)

    Parslow, Graham R.

    2011-01-01

    It was deeply ingrained in the author from his undergraduate studies of psychology and courses in learning theory that people have a rational left brain and a creative right brain. Learning theory suggested that activities needed to be tailored to develop both hemispheres. Handedness in relation to abilities has been commented on from the 1800s by…

  15. Memorization of Sequences of Movements of the Right or the Left Hand by Right- and Left-Handers: Vector Coding.

    Science.gov (United States)

    Bobrova, E V; Bogacheva, I N; Lyakhovetskii, V A; Fabinskaja, A A; Fomina, E V

    2017-01-01

    In order to test the hypothesis of hemisphere specialization for different types of information coding (the right hemisphere, for positional coding; the left one, for vector coding), we analyzed the errors of right and left-handers during a task involving the memorization of sequences of movements by the left or the right hand, which activates vector coding by changing the order of movements in memorized sequences. The task was first performed by the right or the left hand, then by the opposite hand. It was found that both'right- and left-handers use the information about the previous movements of the dominant hand, but not of the non-dom" inant one. After changing the hand, right-handers use the information about previous movements of the second hand, while left-handers do not. We compared our results with the data of previous experiments, in which positional coding was activated, and concluded that both right- and left-handers use vector coding for memorizing the sequences of their dominant hands and positional coding for memorizing the sequences of non-dominant hand. No similar patterns of errors were found between right- and left-handers after changing the hand, which suggests that in right- and left-handersthe skills are transferred in different ways depending on the type of coding.

  16. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

    Science.gov (United States)

    Lee, Jui-Chi; Massironi, Matteo; Ip, Wing-Huen; Giacomini, Lorenza; Ferrari, Sabrina; Penasa, Luca; El-Maarry, Mohamed Ramy; Pajola, Maurizio; Lai, Ian-Lin; Lin, Zhong-Yi; Ferri, Francesca; Sierks, Holger; Barbieri, Cesare; Lamy, Philippe; Rodrigo, Rafael; Koschny, Detlef; Rickman, Hans; Keller, Horst Uwe; Agarwal, Jessica; A'Hearn, Michael F.; Barucci, Maria Antonella; Bertaux, Jean-Loup; Bertini, Ivano; Cremonese, Gabriele; Da Deppo, Vania; Davidsson, Björn; Debei, Stefano; De Cecco, Mariolino; Deller, Jakob; Fornasier, Sonia; Fulle, Marco; Groussin, Olivier; Gutiérrez, Pedro J.; Güttler, Carsten; Hofmann, Marc; Hviid, Stubbe F.; Jorda, Laurent; Knollenberg, Jörg; Kovacs, Gabor; Kramm, J.-Rainer; Kührt, Ekkehard; Küppers, Michael; Lara, Luisa M.; Lazzarin, Monica; Marzari, Francesco; Lopez Moreno, Josè J.; Naletto, Giampiero; Oklay, Nilda; Shi, Xian; Thomas, Nicolas; Tubiana, Cecilia; Vincent, Jean-Baptiste

    2016-11-01

    In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

  17. Dyslexia Treated by Hemisphere Stimulation Technic

    OpenAIRE

    J Gordon Millichap

    1997-01-01

    Results of treatment of severe dyslexia in 80 children, ages 6 to 15 years, using hemisphere stimulation technics, are reported from the outpatient Department for Dyslexia, Child Psychiatric Center, Paedological Institute, Amsterdam, The Netherlands.

  18. Phylogeography of Burkholderia pseudomallei Isolates, Western Hemisphere.

    Science.gov (United States)

    Gee, Jay E; Gulvik, Christopher A; Elrod, Mindy G; Batra, Dhwani; Rowe, Lori A; Sheth, Mili; Hoffmaster, Alex R

    2017-07-01

    The bacterium Burkholderia pseudomallei causes melioidosis, which is mainly associated with tropical areas. We analyzed single-nucleotide polymorphisms (SNPs) among genome sequences from isolates of B. pseudomallei that originated in the Western Hemisphere by comparing them with genome sequences of isolates that originated in the Eastern Hemisphere. Analysis indicated that isolates from the Western Hemisphere form a distinct clade, which supports the hypothesis that these isolates were derived from a constricted seeding event from Africa. Subclades have been resolved that are associated with specific regions within the Western Hemisphere and suggest that isolates might be correlated geographically with cases of melioidosis. One isolate associated with a former World War II prisoner of war was believed to represent illness 62 years after exposure in Southeast Asia. However, analysis suggested the isolate originated in Central or South America.

  19. Is the left forelimb preference indicative of a stressful situation in horses?

    Science.gov (United States)

    Siniscalchi, M; Padalino, B; Lusito, R; Quaranta, A

    2014-09-01

    Evidence for behavioural and brain lateralisation is now widespread among the animal kingdom; lateralisation of limb use (pawedness) occurs in several mammals including both feral and domestic horses. We investigated limb preferences in 14 Quarter Horse during different motor tasks (walking, stepping on and off a step, truck loading and unloading). Population lateralisation was observed in two tasks: horses preferentially used their left forelimb during truck loading and stepping off a step. The results also revealed that horses showed higher scores for anxious behaviours during truck loading suggesting that the use of the left forelimb in this task may reflect the main role of the right hemisphere in control of behaviour during stressful situation. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. MR imaging features of hemispherical spondylosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Vicentini, Joao R.T.; Martinez-Salazar, Edgar L.; Chang, Connie Y.; Bredella, Miriam A.; Rosenthal, Daniel I.; Torriani, Martin [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States)

    2017-10-15

    Hemispherical spondylosclerosis (HS) is a rare degenerative entity characterized by dome-shaped sclerosis of a single vertebral body that may pose a diagnostic dilemma. The goal of this study was to describe the MR imaging features of HS. We identified spine radiographs and CT examinations of subjects with HS who also had MR imaging for correlation. Two musculoskeletal radiologists independently assessed sclerosis characteristics, presence of endplate erosions, marrow signal intensity, and disk degeneration (Pfirrmann scale). We identified 11 subjects (six males, five females, mean 48 ± 10 years) with radiographic/CT findings of HS. The most commonly affected vertebral body was L4 (6/11; 55%). On MR imaging, variable signal intensity was noted, being most commonly low on T1 (8/11, 73%) and high on fat-suppressed T2-weighted (8/11, 73%) images. In two subjects, diffuse post-contrast enhancement was seen in the lesion. Moderate disk degeneration and endplate bone erosions adjacent to sclerosis were present in all subjects. Erosions of the opposite endplate were present in two subjects (2/11, 18%). CT data from nine subjects showed the mean attenuation value of HS was 472 ± 96 HU. HS appearance on MR imaging is variable and may not correlate with the degree of sclerosis seen on radiographs or CT. Disk degenerative changes and asymmetric endplate erosions are consistent markers of HS. (orig.)

  1. Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions.

    Science.gov (United States)

    Aberg, Kristoffer Carl; Doell, Kimberly C; Schwartz, Sophie

    2015-10-28

    Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively). In reinforcement learning, action values are increased when outcomes are better than predicted (positive prediction errors [PEs]) and decreased for worse than predicted outcomes (negative PEs). Because actions with high and low values are approached and avoided, respectively, individual differences in the neural encoding of PEs may influence the balance between approach-avoidance learning. Recent correlational approaches also indicate that biases in approach-avoidance learning involve hemispheric asymmetries in dopamine function. However, the computational and neural mechanisms underpinning such learning biases remain unknown. Here we assessed hemispheric reward asymmetry in striatal activity in 34 human participants who performed a task involving rewards and punishments. We show that the relative difference in reward response between hemispheres relates to individual biases in approach-avoidance learning. Moreover, using a computational modeling approach, we demonstrate that better encoding of positive (vs negative) PEs in dopaminergic midbrain regions is associated with better approach (vs avoidance) learning, specifically in participants with larger reward responses in the left (vs right) ventral striatum. Thus, individual dispositions or traits may be determined by neural processes acting to constrain learning about specific aspects of the world. Copyright © 2015 the authors 0270-6474/15/3514491-10$15.00/0.

  2. Right hemisphere control of visuospatial attention in near space.

    Science.gov (United States)

    Longo, Matthew R; Trippier, Sarah; Vagnoni, Eleonora; Lourenco, Stella F

    2015-04-01

    Traditionally, the right cerebral hemisphere has been considered to be specialized for spatial attention and orienting. A large body of research has demonstrated dissociable representations of the near space immediately surrounding the body and the more distance far space. In this study, we investigated whether right hemisphere activations commonly reported for tasks involving spatial attention (such as the line bisection and landmark tasks) are specific to stimuli presented in near space. In separate blocks of trials, participants judged either whether a vertical transector was to the left or right of the centre of a line (landmark task) or whether the line was red or blue (colour task). Stimuli were seen from four distances (30, 60, 90, 120 cm). We used EEG to measure an ERP component (the 'line-bisection effect') specific to the direction of spatial attention (i.e., landmark minus colour). Consistent with previous results, spatial attention produced a right-lateralized negativity over occipito-parietal channels. The magnitude of this negativity was inversely related to viewing distance, being largest in near space and reduced in far space. These results suggest that the right occipito-temporal cortex may be specialized not just for the orientation of spatial attention generally, but specifically for orienting attention in the near space immediately surrounding the body. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Differences between left- and right-sided neglect revisited: A large cohort study across multiple domains.

    Science.gov (United States)

    Ten Brink, Antonia F; Verwer, Jurre H; Biesbroek, J Matthijs; Visser-Meily, Johanna M A; Nijboer, Tanja C W

    2017-09-01

    Unilateral spatial neglect (USN) is a syndrome that can occur after right- and left-hemisphere damage. It is generally accepted that left-sided USN is more severe than right-sided USN. Evidence for such a difference in other domains is lacking. Primary aims were to compare frequency, severity, region specificity, cognition, physical functioning, and physical independence between left and right USN. Secondary aims were to compare lesion characteristics. A total of 335 stroke patients admitted for inpatient rehabilitation were included. The severity of the lateralized attentional deficit was measured with a shape cancellation and line bisection test (in peripersonal and extrapersonal space) and the Catherine Bergego scale. The Mini-Mental State Examination, Stichting Afasie Nederland score, search organization (i.e., best R and intersections rate), Motricity Index, balance, mobility, and self-care were assessed. Measures were statistically compared between left, right, and no USN patients. Lesion overlay plots were compared with lesion subtraction analyses. Left USN (15.82%) was more frequent than right USN (9.25%). Demographic and stroke characteristics were comparable between groups. The lateralized attentional deficit was most severe in left USN. USN in both peripersonal and extrapersonal space was more frequently left-sided in nature. Search efficiency was lower in left USN. Balance was poorer in right USN. No differences between left and right USN were found for cognitive ability, communication, motor strength, mobility, and self-care. Most patients with left USN had right-hemispheric lesions, whereas patients with right USN could have lesions in either the left or the right hemisphere. To conclude, left and right USN are both common after stroke. Although the lateralized attention deficit is worse in left than in right USN, consequences at the level of physical functioning and physical independence are largely comparable. From a clinical perspective, it is

  4. Hemispherically asymmetric trade wind changes as signatures of past ITCZ shifts

    Science.gov (United States)

    McGee, David; Moreno-Chamarro, Eduardo; Green, Brian; Marshall, John; Galbraith, Eric; Bradtmiller, Louisa

    2018-01-01

    The atmospheric Hadley cells, which meet at the Intertropical Convergence Zone (ITCZ), play critical roles in transporting heat, driving ocean circulation and supplying precipitation to the most heavily populated regions of the globe. Paleo-reconstructions can provide concrete evidence of how these major features of the atmospheric circulation can change in response to climate perturbations. While most such reconstructions have focused on ITCZ-related rainfall, here we show that trade wind proxies can document dynamical aspects of meridional ITCZ shifts. Theoretical expectations based on angular momentum constraints and results from freshwater hosing simulations with two different climate models predict that ITCZ shifts due to anomalous cooling of one hemisphere would be accompanied by a strengthening of the Hadley cell and trade winds in the colder hemisphere, with an opposite response in the warmer hemisphere. This expectation of hemispherically asymmetric trade wind changes is confirmed by proxy data of coastal upwelling and windblown dust from the Atlantic basin during Heinrich stadials, showing trade wind strengthening in the Northern Hemisphere and weakening in the Southern Hemisphere subtropics in concert with southward ITCZ shifts. Data from other basins show broadly similar patterns, though improved constraints on past trade wind changes are needed outside the Atlantic Basin. The asymmetric trade wind changes identified here suggest that ITCZ shifts are also marked by intensification of the ocean's wind-driven subtropical cells in the cooler hemisphere and a weakening in the warmer hemisphere, which induces cross-equatorial oceanic heat transport into the colder hemisphere. This response would be expected to prevent extreme meridional ITCZ shifts in response to asymmetric heating or cooling. Understanding trade wind changes and their coupling to cross-equatorial ocean cells is key to better constraining ITCZ shifts and ocean and atmosphere dynamical

  5. Differences between left- and right-sided neglect revisited : A large cohort study across multiple domains

    NARCIS (Netherlands)

    Ten Brink, Antonia F.; Verwer, Jurre H.; Biesbroek, J. Matthijs; Visser-Meily, Johanna M. A.; Nijboer, Tanja C.W.

    2017-01-01

    Unilateral spatial neglect (USN) is a syndrome that can occur after right- and left-hemisphere damage. It is generally accepted that left-sided USN is more severe than right-sided USN. Evidence for such a difference in other domains is lacking. Primary aims were to compare frequency, severity,

  6. Right away: A late, right-lateralized category effect complements an early, left-lateralized category effect in visual search.

    Science.gov (United States)

    Constable, Merryn D; Becker, Stefanie I

    2017-10-01

    According to the Sapir-Whorf hypothesis, learned semantic categories can influence early perceptual processes. A central finding in support of this view is the lateralized category effect-namely, the finding that categorically different colors (e.g., blue and green hues) can be discriminated faster than colors within the same color category (e.g., different hues of green), especially when they are presented in the right visual field. Because the right visual field projects to the left hemisphere, this finding has been popularly couched in terms of the left-lateralization of language. However, other studies have reported bilateral category effects, which has led some researchers to question the linguistic origins of the effect. Here we examined the time course of lateralized and bilateral category effects in the classical visual search paradigm by means of eyetracking and RT distribution analyses. Our results show a bilateral category effect in the manual responses, which is combined of an early, left-lateralized category effect and a later, right-lateralized category effect. The newly discovered late, right-lateralized category effect occurred only when observers had difficulty locating the target, indicating a specialization of the right hemisphere to find categorically different targets after an initial error. The finding that early and late stages of visual search show different lateralized category effects can explain a wide range of previously discrepant findings.

  7. Effects of daily noise on fetuses and cerebral hemisphere specialization in children

    Science.gov (United States)

    Ando, Y.

    1988-12-01

    This paper first provides an overview of work by the author and colleagues on effects of noise on fetuses demonstrating growth inhibition. As a second issue, the effects of daily noise on the mental abilities of children are discussed in relation to task specification of cerebral hemispheres. Two different types of mental tasks were given to a total of 1286 children (7-10 years old) who live in a noisy area around an international airport or in a neighbouring quiet area, under conditions of no sound, jet-plane noise stimulus and music stimulus. In the quiet neighborhood, results may support a model that noise and calculation tasks are separately processed in the right and left cerebral hemisphere, respectively. Music perception and calculation are considered to be processed one after the other in the left hemisphere. In the pattern search task used as the right hemispheric task, no significant differences appeared under either stimulus sound, with the exception of a slight interference observed in the noise group. In the noisy living area, however, effects of temporary sound on mental tasks appeared to be quite different from the first-mentioned results. These facts suggest that daily noise affects the development of cerebral specialization of growing children. As little is known about effects of noise on growing children, it is recommended that international cooperation be initiated to establish the need for and conditions of healthy sound environments.

  8. Aging changes 3D perception: Evidence for hemispheric rebalancing of lateralized processes.

    Science.gov (United States)

    Andrews, Bridget; d'Avossa, Giovanni; Sapir, Ayelet

    2017-05-01

    When judging the 3D shape of a shaded image, young observers assume that the light source is placed above and to the left. This leftward bias has been attributed to hemispheric lateralization or experiential factors. Since aging is associated with loss of hemispheric lateralization, in the current study we measured the effect of aging on the assumed light source direction. Older participants exhibited, on average, a decreased left bias compared to young participants, as well as greater within-group variability in the distribution of assumed light source directions. In a separate sample of young and old participants, we replicated the age related effect in the assumed light source direction. Furthermore, in both young and old participants the assumed light source direction and the lateralized bias in a line bisection task were correlated. These findings suggest that diminished hemispheric lateralization, which accompanies aging, may affect the perception of the 3D structure of shaded surfaces. Shape from shading may thus provide a simple behavioral tool to track age related changes in hemispheric organization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Hemispherical Resonator Gyroscope Accuracy Analysis Under Temperature Influence

    OpenAIRE

    Boran LI; Guangcheng MA; Changhong WANG

    2014-01-01

    Frequency splitting of hemispherical resonator gyroscope will change as system operating temperature changes. This phenomenon leads to navigation accuracy of hemispherical resonator gyroscope reduces. By researching on hemispherical resonator gyroscope dynamical model and its frequency characteristic, the frequency splitting formula and the precession angle formula of gyroscope vibrating mode based on hemispherical resonator gyroscope dynamic equation parameters are derived. By comparison, gy...

  10. Sex differences and functional hemispheric asymmetries during number comparison.

    Science.gov (United States)

    Harris, TiAnni; Scheuringer, Andrea; Pletzer, Belinda

    2018-01-08

    Global-local stimuli are hierarchical structures consisting of a larger global structure which is composed of smaller local stimuli. Numbers are also constructed hierarchically, with multi-digit numbers being made up from single digits. During two-digit number comparison, compatible items (larger number contains larger unit digit, e.g., 53 vs. 68) are processed faster and more accurately than incompatible items (smaller number contains larger unit digit, e.g., 58 vs. 63). This so-called unit-decade-compatibility effect has challenged the holistic model of number processing and suggests that the processing of number magnitudes occurs at least in part, decomposed, i.e., separately for each digit. Thus, the compatibility effect is indicative of how decomposed numbers are processed, thereby sharing similarities with traditional global-local processing of hierarchical stimuli. The goal of this study was to investigate whether factors that have been shown to reliably influence global-local processing also affect the compatibility effect during number comparison. Those include visual hemifield, sex, and menstrual cycle phase in women. One hundred sixty participants, 77 naturally cycling women and 83 men, completed a two-digit number comparison task twice, with test-sessions time-locked to the early follicular or mid-luteal cycle phase in women. Number comparison stimuli were presented to the right or left hemifield, respectively. We observed a stronger compatibility effect in the right visual hemifield compared to left visual hemifield and in women compared to men, but no evidence for an influence of menstrual cycle phase in women could be found. Hemispheric asymmetries in holistic versus decomposed number processing could be demonstrated for the first time, suggesting a similar hemispheric modulation for number magnitude processing as for global-local processing.

  11. Language deficits as a possible symptom of right hemisphere dysfunctions in Asperger’s syndrome

    Directory of Open Access Journals (Sweden)

    Anita Bryńska

    2010-12-01

    Full Text Available Qualitative communication disorders belong to the key symptoms of pervasive developmental disorders (PDD. The severity of the symptoms of communication disorders varies depending on the type of PDD, from the lack of functional speech to overdeveloped verbal competencies measured by standardized scales. In Asperger’s syndrome (AS, observed language abnormalities include: pragmatics (application of language in social context, semantics (identifying different meanings of the same word and prosody (rhythm, intonation and modulation of speech. In the case of AS, the difference between formal language skills, i.e. within morphological, phonological and syntactic functions, and semantic and pragmatic deficits is clearly noticeable and distinctive. This situation arouses some questions about neurobiological conditions of these deficits. The language functions are among the first functions for which locations in the brain have been established. Traditionally they have been ascribed to some regions in the left hemisphere; they undergo lateralization and are accomplished owing to the activity of the primary, secondary and tertiary regions of associative cortex. However, there is also quite a lot of evidence suggesting that the right hemisphere plays an important role in communication processes, especially in some aspects of pragmatics and discourse. The analysis of communication deficits observed in patients with acquired right hemisphere damages and patients with AS as well as abnormal patterns of hemispheric asymmetry in this group of patients, suggest that the right hemisphere is involved in aetiology of PDD.

  12. A new look at two old problems in electrostatics, or much ado with hemispheres

    International Nuclear Information System (INIS)

    Das Gupta, Ananda

    2007-01-01

    In this paper, we take a look at two electrostatics problems concerning hemispheres. The first problem concerns the direction of the electric field on the flat cap of a uniformly charged hemisphere. We show that the symmetry and principle of superposition coupled with Gauss's law gives a delightfully simple solution and then go on to examine how the more 'powerful' methods of partial differential equations can be used to arrive at the same solution. A second problem that deals with the force of repulsion between the two hemispheres of a uniformly charged sphere is also dealt with from the same viewpoint. We feel that this approach could be quite instructive to students

  13. Reduced contralateral hemispheric flow measured by SPECT in cerebellar lesions

    DEFF Research Database (Denmark)

    Sönmezoğlu, K; Sperling, B; Henriksen, T

    1993-01-01

    Four patients with clinical signs of cerebellar stroke were studied twice by SPECT using 99mTc-HMPAO as a tracer for cerebral blood flow (CBF). When first scanned 6 to 22 days after onset, all had a region of very low CBF in the symptomatic cerebellar hemisphere, and a mild to moderate CBF...... reduction (average 10%) in contralateral hemispheric cortex. In all four cases clinical signs of unilateral cerebellar dysfunction were still present when rescanned 1 to 4 months later and the relative CBF decrease in the contralateral cortex of the forebrain also remained. The basal ganglia contralateral...... to the cerebellar lesion CBF showed variable alterations. A relative CBF decrease was seen in upper part of basal ganglia in all four cases, but it was not a constant phenomenon. A relative CBF increase in both early and late SPECT scans was seen at low levels of neostriatum in two cases. The remote CBF changes...

  14. Are Karakoram temperatures out of phase compared to hemispheric trends?

    Science.gov (United States)

    Asad, Fayaz; Zhu, Haifeng; Zhang, Hui; Liang, Eryuan; Muhammad, Sher; Farhan, Suhaib Bin; Hussain, Iqtidar; Wazir, Muhammad Atif; Ahmed, Moinuddin; Esper, Jan

    2017-05-01

    In contrast to a global retreating trend, glaciers in the Karakoram showed stability and/or mass gaining during the past decades. This "Karakoram Anomaly" has been assumed to result from an out-of-phase temperature trend compared to hemispheric scales. However, the short instrumental observations from the Karakoram valley bottoms do not support a quantitative assessment of long-term temperature trends in this high mountain area. Here, we presented a new April-July temperature reconstruction from the Karakoram region in northern Pakistan based on a high elevation ( 3600 m a.s.l.) tree-ring chronology covering the past 438 years (AD 1575-2012). The reconstruction passes all statistical calibration and validation tests and represents 49 % of the temperature variance recorded over the 1955-2012 instrumental period. It shows a substantial warming accounting to about 1.12 °C since the mid-twentieth century, and 1.94 °C since the mid-nineteenth century, and agrees well with the Northern Hemisphere temperature reconstructions. These findings provide evidence that the Karakoram temperatures are in-phase, rather than out-of-phase, compared to hemispheric scales since the AD 1575. The synchronous temperature trends imply that the anomalous glacier behavior reported from the Karakoram may need further explanations beyond basic regional thermal anomaly.

  15. Aphasia following left thalamic hemorrhage

    International Nuclear Information System (INIS)

    Makishita, Hideo; Miyasaka, Motomaro; Tanizaki, Yoshio; Yanagisawa, Nobuo; Sugishita, Morihiro.

    1984-01-01

    We reported 7 patients with left thalamic hemorrhage in the chronic stage (from 1.5 months to 4.5 months), and described language disorders examined by Western Aphasia Battery (WAB) and measured cerebral blood flow by single photon emission CT. Examination of language by WAB revealed 4 aphasics out of 7 cases, and 3 patients had no language deficit. The patient with Wernicke's aphasia showed low density area only in the left posterior thalamus in X-ray CT, and revealed severe low blood flow area extending to left temporal lobe in emission CT. In the case with transcortical sensory aphasia, although X-ray CT showed no obvious low density area, emission CT revealed moderate low flow area in watershed area that involved the territory between posterior cerebral and middle cerebral arteries in the left temporooccipital region in addition to low blood flow at the left thalamus. In one of the two patients classified as anomic aphasia, whose score of repetition (8.4) was higher than that of comprehension (7.4), emission CT showed slight low flow area at the temporo-occipital region similarly as the case with transcortical sensory aphasia. In another case with anomic aphasia, scored 9 on both fluensy and comprehension subtests and 10 on repetition, there was wide low density area all over the left thalamus and midline shift to the right in X-ray CT, and emission CT showed severe low blood flow in the same region spreading widely toward the cerebral surface. On the other hand, in all of the 3 patients without aphasia, emission CT showed low flow region restricted to the left thalamus. (J.P.N.)

  16. Left Main Coronary Artery Aneurysm

    Directory of Open Access Journals (Sweden)

    Hossein Doustkami

    2016-07-01

    Full Text Available Aneurysms of the left main coronary artery are exceedingly rare clinical entities, encountered incidentally in approximately 0.1% of patients who undergo routine angiography. The most common cause of coronary artery aneurysms is atherosclerosis. Angiography is the gold standard for diagnosis and treatment. Depending on the severity of the coexisting coronary stenosis, patients with left main coronary artery aneurysms can be effectively managed either surgically or pharmacologically. We herein report a case of left main coronary artery aneurysm in a 72-year-old man with a prior history of hypertension presenting to our hospital because of unstable angina. The electrocardiogram showed ST-segment depression and T-wave inversion in the precordial leads. All the data of blood chemistry were normal. Echocardiography showed akinetic anterior wall, septum, and apex, mild mitral regurgitation and ejection fraction of 45%. Coronary angiography revealed a saccular aneurysm of the left main coronary artery with significant stenosis in the left anterior descending, left circumflex, and right coronary artery. The patient immediately underwent coronary artery bypass grafting and ligation of the aneurysm. At six months’ follow-up, he remained asymptomatic.

  17. Right is not always wrong: DTI and fMRI evidence for the reliance of reading comprehension on language-comprehension networks in the right hemisphere.

    Science.gov (United States)

    Horowitz-Kraus, Tzipi; Grainger, Molly; DiFrancesco, Mark; Vannest, Jennifer; Holland, Scott K

    2015-03-01

    The Simple View theory suggests that reading comprehension relies on automatic recognition of words combined with language comprehension. The goal of the current study was to examine the structural and functional connectivity in networks supporting reading comprehension and their relationship with language comprehension within 7-9 year old children using Diffusion Tensor Imaging (DTI) and fMRI during a Sentence Picture Matching task. Fractional Anisotropy (FA) values in the left and right Inferior Longitudinal Fasciculus (ILF) and Superior Longitudinal Fasciculus (SLF), known language-related tracts, were correlated from DTI data with scores from the Woodcock-Johnson III (WJ-III) Passage Comprehension sub-test. Brodmann areas most proximal to white-matter regions with significant correlation to Passage Comprehension scores were chosen as Regions-of-Interest (ROIs) and used as seeds in a functional connectivity analysis using the Sentence Picture Matching task. The correlation between percentile scores for the WJ-III Passage Comprehension subtest and the FA values in the right and left ILF and SLF indicated positive correlation in language-related ROIs, with greater distribution in the right hemisphere, which in turn showed strong connectivity in the fMRI data from the Sentence Picture Matching task. These results support the participation of the right hemisphere in reading comprehension and may provide physiologic support for a distinction between different types of reading comprehension deficits vs difficulties in technical reading.

  18. Reading laterally: the cerebral hemispheric use of spatial frequencies in visual word recognition.

    Science.gov (United States)

    Tadros, Karine; Dupuis-Roy, Nicolas; Fiset, Daniel; Arguin, Martin; Gosselin, Frédéric

    2013-01-04

    It is generally accepted that the left hemisphere (LH) is more capable for reading than the right hemisphere (RH). Left hemifield presentations (initially processed by the RH) lead to a globally higher error rate, slower word identification, and a significantly stronger word length effect (i.e., slower reaction times for longer words). Because the visuo-perceptual mechanisms of the brain for word recognition are primarily localized in the LH (Cohen et al., 2003), it is possible that this part of the brain possesses better spatial frequency (SF) tuning for processing the visual properties of words than the RH. The main objective of this study is to determine the SF tuning functions of the LH and RH for word recognition. Each word image was randomly sampled in the SF domain using the SF bubbles method (Willenbockel et al., 2010) and was presented laterally to the left or right visual hemifield. As expected, the LH requires less visual information than the RH to reach the same level of performance, illustrating the well-known LH advantage for word recognition. Globally, the SF tuning of both hemispheres is similar. However, these seemingly identical tuning functions hide important differences. Most importantly, we argue that the RH requires higher SFs to identify longer words because of crowding.

  19. Hemispheric Asymmetry of Endogenous Neural Oscillations in Young Children: Implications for Hearing Speech In Noise.

    Science.gov (United States)

    Thompson, Elaine C; Woodruff Carr, Kali; White-Schwoch, Travis; Tierney, Adam; Nicol, Trent; Kraus, Nina

    2016-01-25

    Speech signals contain information in hierarchical time scales, ranging from short-duration (e.g., phonemes) to long-duration cues (e.g., syllables, prosody). A theoretical framework to understand how the brain processes this hierarchy suggests that hemispheric lateralization enables specialized tracking of acoustic cues at different time scales, with the left and right hemispheres sampling at short (25 ms; 40 Hz) and long (200 ms; 5 Hz) periods, respectively. In adults, both speech-evoked and endogenous cortical rhythms are asymmetrical: low-frequency rhythms predominate in right auditory cortex, and high-frequency rhythms in left auditory cortex. It is unknown, however, whether endogenous resting state oscillations are similarly lateralized in children. We investigated cortical oscillations in children (3-5 years; N = 65) at rest and tested our hypotheses that this temporal asymmetry is evident early in life and facilitates recognition of speech in noise. We found a systematic pattern of increasing leftward asymmetry for higher frequency oscillations; this pattern was more pronounced in children who better perceived words in noise. The observed connection between left-biased cortical oscillations in phoneme-relevant frequencies and speech-in-noise perception suggests hemispheric specialization of endogenous oscillatory activity may support speech processing in challenging listening environments, and that this infrastructure is present during early childhood.

  20. Differences in lateral hemispheric asymmetries of glucose utilization between early- and late-onset Alzheimer-type dementia

    Energy Technology Data Exchange (ETDEWEB)

    Koss, E.; Friedland, R.P.; Ober, B.A.; Jagust, W.J.

    1985-05-01

    Positron emission tomography with (/sup 18/F)fluorodeoxyglucose revealed greater right than left hemispheric impairment of cortical glucose metabolism in patients with probable Alzheimer's disease who were younger than 65 but not in those over 65. This asymmetry was related to poor visuospatial performance.

  1. Left and right reaction time differences to the sound intensity in normal and AD/HD children.

    Science.gov (United States)

    Baghdadi, Golnaz; Towhidkhah, Farzad; Rostami, Reza

    2017-06-01

    Right hemisphere, which is attributed to the sound intensity discrimination, has abnormality in people with attention deficit/hyperactivity disorder (AD/HD). However, it is not studied whether the defect in the right hemisphere has influenced on the intensity sensation of AD/HD subjects or not. In this study, the sensitivity of normal and AD/HD children to the sound intensity was investigated. Nineteen normal and fourteen AD/HD children participated in the study and performed a simple auditory reaction time task. Using the regression analysis, the sensitivity of right and left ears to various sound intensity levels was examined. The statistical results showed that the sensitivity of AD/HD subjects to the intensity was lower than the normal group (p  0.05). However, in control group the left pathway was more sensitive to the sound intensity level than the right one (p = 0.0156). It can be probable that the deficit of the right hemisphere has influenced on the auditory sensitivity of AD/HD children. The possible existent deficits of other auditory system components such as middle ear, inner ear, or involved brain stem nucleuses may also lead to the observed results. The development of new biomarkers based on the sensitivity of the brain hemispheres to the sound intensity has been suggested to estimate the risk of AD/HD. Designing new technique to correct the auditory feedback has been also proposed in behavioral treatment sessions. Copyright © 2017. Published by Elsevier B.V.

  2. Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport

    Directory of Open Access Journals (Sweden)

    D. Howard

    2017-09-01

    Full Text Available Mercury is a toxic element of serious concern for human and environmental health. Understanding its natural cycling in the environment is an important goal towards assessing its impacts and the effectiveness of mitigation strategies. Due to the unique chemical and physical properties of mercury, the atmosphere is the dominant transport pathway for this heavy metal, with the consequence that regions far removed from sources can be impacted. However, there exists a dearth of long-term monitoring of atmospheric mercury, particularly in the tropics and Southern Hemisphere. This paper presents the first 2 years of gaseous elemental mercury (GEM measurements taken at the Australian Tropical Atmospheric Research Station (ATARS in northern Australia, as part of the Global Mercury Observation System (GMOS. Annual mean GEM concentrations determined at ATARS (0.95 ± 0.12 ng m−3 are consistent with recent observations at other sites in the Southern Hemisphere. Comparison with GEM data from other Australian monitoring sites suggests a concentration gradient that decreases with increasing latitude. Seasonal analysis shows that GEM concentrations at ATARS are significantly lower in the distinct wet monsoon season than in the dry season. This result provides insight into alterations of natural mercury cycling processes as a result of changes in atmospheric humidity, oceanic/terrestrial fetch, and convective mixing, and invites future investigation using wet mercury deposition measurements. Due to its location relative to the atmospheric equator, ATARS intermittently samples air originating from the Northern Hemisphere, allowing an opportunity to gain greater understanding of inter-hemispheric transport of mercury and other atmospheric species. Diurnal cycles of GEM at ATARS show distinct nocturnal depletion events that are attributed to dry deposition under stable boundary layer conditions. These cycles provide strong further evidence supportive of

  3. Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport

    Science.gov (United States)

    Howard, Dean; Nelson, Peter F.; Edwards, Grant C.; Morrison, Anthony L.; Fisher, Jenny A.; Ward, Jason; Harnwell, James; van der Schoot, Marcel; Atkinson, Brad; Chambers, Scott D.; Griffiths, Alan D.; Werczynski, Sylvester; Williams, Alastair G.

    2017-09-01

    Mercury is a toxic element of serious concern for human and environmental health. Understanding its natural cycling in the environment is an important goal towards assessing its impacts and the effectiveness of mitigation strategies. Due to the unique chemical and physical properties of mercury, the atmosphere is the dominant transport pathway for this heavy metal, with the consequence that regions far removed from sources can be impacted. However, there exists a dearth of long-term monitoring of atmospheric mercury, particularly in the tropics and Southern Hemisphere. This paper presents the first 2 years of gaseous elemental mercury (GEM) measurements taken at the Australian Tropical Atmospheric Research Station (ATARS) in northern Australia, as part of the Global Mercury Observation System (GMOS). Annual mean GEM concentrations determined at ATARS (0.95 ± 0.12 ng m-3) are consistent with recent observations at other sites in the Southern Hemisphere. Comparison with GEM data from other Australian monitoring sites suggests a concentration gradient that decreases with increasing latitude. Seasonal analysis shows that GEM concentrations at ATARS are significantly lower in the distinct wet monsoon season than in the dry season. This result provides insight into alterations of natural mercury cycling processes as a result of changes in atmospheric humidity, oceanic/terrestrial fetch, and convective mixing, and invites future investigation using wet mercury deposition measurements. Due to its location relative to the atmospheric equator, ATARS intermittently samples air originating from the Northern Hemisphere, allowing an opportunity to gain greater understanding of inter-hemispheric transport of mercury and other atmospheric species. Diurnal cycles of GEM at ATARS show distinct nocturnal depletion events that are attributed to dry deposition under stable boundary layer conditions. These cycles provide strong further evidence supportive of a multi-hop model of GEM

  4. Cosmetic appreciation of lateralization of peripheral facial palsy: 'preference for left or right, true or mirror image?'.

    Science.gov (United States)

    Pouwels, Sjaak; Ingels, Koen; van Heerbeek, Niels; Beurskens, Carien

    2014-09-01

    There have been several studies in the past depicting asymmetry in 'normal' human faces. Evidence supports the fact that the right hemisphere is superior in the recognition of emotions expressed by the human face and indicates a right hemispheric specialization for processing emotional information. The primary aim of this study is to determine whether there is a difference in cosmetic appreciation of a left peripheral facial palsy compared to a right peripheral facial palsy? Pictures of patients with a facial palsy with House-Brackmann II-VI were reversed as a mirror image and offered as a pair of pictures, together with the true image. Forty-two patients and 24 medical professionals familiar with facial palsy were asked to choose the most attractive photograph. The primary 'end' point was the most attractive side in the pictures chosen by medical professionals and patients. The secondary 'end' points consisted of the preferences for the mirror or true image, and influences of the House-Brackmann score and age. Medical professionals preferred the photographs from patients with a right and left peripheral facial palsy (PFP) in, respectively, a mean of 44 % (41-48 %) and 56 % (52-59 %) of the pictures (p = 0.02). When comparing mirror and true image, patients with a left-sided facial palsy chose their mirror and true image as most attractive in 90 and 10 %, respectively (p 0.05). Subanalysis of patients with a PFP House-Brackmann score V and VI showed that medical professionals did not have a significant preference for a left nor right-sided facial palsy. Patients with a left-sided facial palsy chose their mirror image in all cases and patients with a right-sided palsy chose their mirror and true image in resp. 33 and 67 %. The House-Brackmann score (p = 0.52) and age (p = 0.73) of the patients did not influence preferences. This study, demonstrating that medical professionals find a right-sided facial palsy cosmetically less attractive than a left-sided, has

  5. Music reading expertise modulates hemispheric lateralization in English word processing but not in Chinese character processing.

    Science.gov (United States)

    Li, Sara Tze Kwan; Hsiao, Janet Hui-Wen

    2018-03-17

    Music notation and English word reading both involve mapping horizontally arranged visual components to components in sound, in contrast to reading in logographic languages such as Chinese. Accordingly, music-reading expertise may influence English word processing more than Chinese character processing. Here we showed that musicians named English words significantly faster than non-musicians when words were presented in the left visual field/right hemisphere (RH) or the center position, suggesting an advantage of RH processing due to music reading experience. This effect was not observed in Chinese character naming. A follow-up ERP study showed that in a sequential matching task, musicians had reduced RH N170 responses to English non-words under the processing of musical segments as compared with non-musicians, suggesting a shared visual processing mechanism in the RH between music notation and English non-word reading. This shared mechanism may be related to the letter-by-letter, serial visual processing that characterizes RH English word recognition (e.g., Lavidor & Ellis, 2001), which may consequently facilitate English word processing in the RH in musicians. Thus, music reading experience may have differential influences on the processing of different languages, depending on their similarities in the cognitive processes involved. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Marine anthropogenic radiotracers in the Southern Hemisphere: New sampling and analytical strategies

    DEFF Research Database (Denmark)

    Levy, I.; Povinec, P.P.; Aoyama, M.

    2011-01-01

    The Japan Agency for Marine Earth Science and Technology conducted in 2003–2004 the Blue Earth Global Expedition (BEAGLE2003) around the Southern Hemisphere Oceans, which was a rare opportunity to collect many seawater samples for anthropogenic radionuclide studies. We describe here sampling...... showed a reasonable agreement between the participating laboratories. The obtained data on the distribution of 137Cs and plutonium isotopes in seawater represent the most comprehensive results available for the Southern Hemisphere Oceans....

  7. Crossed Aphasia in a Dextral without “Minor” Hemisphere Signs

    Directory of Open Access Journals (Sweden)

    J. C. Marshall

    1992-01-01

    Full Text Available A case of severe aphasia after right hemisphere stroke, confirmed by CT, in an unambiguously dextral patient is reported. The patient showed no limb apraxia, and performed well on a test of “closure” (Mooney faces. Extensive testing revealed no signs of visuo-spatial neglect. We conclude that “pure” crossed aphasia can occur in the absence of symptoms normally associated with right hemisphere lesions.

  8. Southern Hemisphere Upper Thermospheric Wind Climatology

    Science.gov (United States)

    Dhadly, M. S.; Emmert, J. T.; Drob, D. P.

    2017-12-01

    This study is focused on the poorly understood large-scale upper thermospheric wind dynamics in the southern polar cap, auroral, and mid latitudes. The gaps in our understanding of the dynamic high-latitude thermosphere are largely due to the sparseness of thermospheric wind measurements. Using data from current observational facilities, it is unfeasible to construct a synoptic picture of the Southern Hemisphere upper thermospheric winds. However, enough data with wide spatial and temporal coverage have accumulated to construct a meaningful statistical analysis of winds as function of season, magnetic latitude, and magnetic local time. We use long-term data from nine ground-based stations located at different southern high latitudes and three space-based instruments. These diverse data sets possess different geometries and different spatial and solar coverage. The major challenge of the effort is to combine these disparate sources of data into a coherent picture while overcoming the sampling limitations and biases among the datasets. Our preliminary analyses show mutual biases present among some of them. We first address the biases among various data sets and then combine them in a coherent way to construct maps of neutral winds for various seasons. We then validate the fitted climatology against the observational data and compare with corresponding fits of 25 years of simulated winds from the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model. This study provides critical insight into magnetosphere-ionosphere-thermosphere coupling and sets a necessary benchmark for validating new observations and tuning first-principles models.

  9. Practice makes two hemispheres almost perfect.

    Science.gov (United States)

    Cherbuin, Nicolas; Brinkman, Cobie

    2005-08-01

    Some tasks produce a performance advantage for conditions that require the processing of stimuli in two visual fields compared to conditions where single hemifield processing is sufficient. This advantage, however, disappears with practice. Although no definitive evidence yet exists, there are several possible mechanisms that might lead to improved performance of within- compared to across-hemisphere processing with practice. These include a shift from a more demanding, algorithmic strategy to a less demanding memory-retrieval strategy (e.g., [G. Logan, Toward an instance theory of automatisation. Psych. Rev. 95 (1988) 492-527]), as discussed by Weissman and Compton [D.H. Weissman, R.J. Compton, Practice makes a hemisphere perfect: the advantage of interhemispheric recruitment is eliminated with practice. Laterality, 8 (4) (2003) 361-375], and/or a more generalised practice effect [K. Kirsner, C. Speelman, Skill acquisition and repetition priming: one principle, many processes? J. Exp. Psychol., Learn. Mem. Cogn., 22 (1996) 563-575]. Contrary to Weissman and Compton findings, our results suggest that although single-hemisphere performance improves with practice, bi-hemispheric performance also improves substantially. Furthermore, these effects do not appear to be due to a shift in strategy but rather due to a general practice effect.

  10. An Evaluative Review of Hemispheric Learning Potential

    Science.gov (United States)

    1985-10-01

    function in the cerebral cortex first assumed importance in the work of the phrenologist Franz Joseph Gall. The early 19th-century neu- rologists...Einstein, Picasso, Kafka , and Eileen Garrett. Cortes and Montezuma are also opposed as the contrast of two hemisphere styles. Moore (1984) integrated

  11. Significance of Hemispheric Security for Mexico

    Science.gov (United States)

    2003-04-07

    WORD COUNT = 7,976 20 21 ENDNOTES 1 Eugenio Anguiano, “ America Latina , en marcha hacia una nueva crisis,” El Universal, 20 Noviembre 2002 [newspaper...language=printer; Internet ; accessed 12 Sep 2002. 46 Joseph R. Nuñez, A 21st Century Security Architecture for the Americas : Multilateral...1 LATIN AMERICA AND GLOBAL CHALLENGES........................................................... 1 HEMISPHERIC COOPERATIVE

  12. Forest carbon sinks in the northern hemisphere

    NARCIS (Netherlands)

    Goodale, C.L.; Apps, M.J.; Birdsey, R.A.; Field, C.B.; Heath, L.S.; Houghton, R.A.; Jenkins, J.C.; Kohlmaier, G.H.; Kurz, W.; Liu, S.R.; Nabuurs, G.J.; Nilsson, S.; Shvidenko, A.Z.

    2002-01-01

    There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measuretment-based constraints on the magnitude

  13. Enhanced neural synchrony between left auditory and premotor cortex is associated with successful phonetic categorization.

    Science.gov (United States)

    Alho, Jussi; Lin, Fa-Hsuan; Sato, Marc; Tiitinen, Hannu; Sams, Mikko; Jääskeläinen, Iiro P

    2014-01-01

    The cortical dorsal auditory stream has been proposed to mediate mapping between auditory and articulatory-motor representations in speech processing. Whether this sensorimotor integration contributes to speech perception remains an open question. Here, magnetoencephalography was used to examine connectivity between auditory and motor areas while subjects were performing a sensorimotor task involving speech sound identification and overt repetition. Functional connectivity was estimated with inter-areal phase synchrony of electromagnetic oscillations. Structural equation modeling was applied to determine the direction of information flow. Compared to passive listening, engagement in the sensorimotor task enhanced connectivity within 200 ms after sound onset bilaterally between the temporoparietal junction (TPJ) and ventral premotor cortex (vPMC), with the left-hemisphere connection showing directionality from vPMC to TPJ. Passive listening to noisy speech elicited stronger connectivity than clear speech between left auditory cortex (AC) and vPMC at ~100 ms, and between left TPJ and dorsal premotor cortex (dPMC) at ~200 ms. Information flow was estimated from AC to vPMC and from dPMC to TPJ. Connectivity strength among the left AC, vPMC, and TPJ correlated positively with the identification of speech sounds within 150 ms after sound onset, with information flowing from AC to TPJ, from AC to vPMC, and from vPMC to TPJ. Taken together, these findings suggest that sensorimotor integration mediates the categorization of incoming speech sounds through reciprocal auditory-to-motor and motor-to-auditory projections.

  14. Schizotypy and hemispheric asymmetry: Results from two Chapman scales, the O-LIFE questionnaire, and two laterality measures.

    Science.gov (United States)

    Schofield, Kerry; Mohr, Christine

    2014-01-01

    Schizotypy is a multidimensional personality construct representing the extension of psychosis-like traits into the general population. Schizotypy has been associated with attenuated expressions of many of the same neuropsychological abnormalities as schizophrenia, including atypical pattern of functional hemispheric asymmetry. Unfortunately the previous literature on links between schizotypy and hemispheric asymmetry is inconsistent, with some research indicating that elevated schizotypy is associated with relative right over left hemisphere shifts, left over right hemisphere shifts, bilateral impairments, or with no hemispheric differences at all. This inconsistency may result from different methodologies, scales, and/or sex proportions between studies. In a within-participant design we tested for the four possible links between laterality and schizotypy by comparing the relationship between two common self-report measures of multidimensional schizotypy (the O-LIFE questionnaire, and two Chapman scales, magical ideation and physical anhedonia) and performance in two computerised lateralised hemifield paradigms (lexical decision, chimeric face processing) in 80 men and 79 women. Results for the two scales and two tasks did not unequivocally support any of the four possible links. We discuss the possibilities that a link between schizotypy and laterality (1) exists but is subtle, probably fluctuating, unable to be assessed by traditional methodologies used here; (2) does not exist, or (3) is indirect, mediated by other factors (e.g., stress-responsiveness, handedness, drug use) whose influences need further exploration.

  15. Timing of emotion representation in right and left occipital region: Evidence from combined TMS-EEG.

    Science.gov (United States)

    Mattavelli, Giulia; Rosanova, Mario; Casali, Adenauer G; Papagno, Costanza; Romero Lauro, Leonor J

    2016-07-01

    Neuroimaging and electrophysiological studies provide evidence of hemispheric differences in processing faces and, in particular, emotional expressions. However, the timing of emotion representation in the right and left hemisphere is still unclear. Transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) was used to explore cortical responsiveness during behavioural tasks requiring processing of either identity or expression of faces. Single-pulse TMS was delivered 100ms after face onset over the medial prefrontal cortex (mPFC) while continuous EEG was recorded using a 60-channel TMS-compatible amplifier; right premotor cortex (rPMC) was also stimulated as control site. The same face stimuli with neutral, happy and fearful expressions were presented in separate blocks and participants were asked to complete either a facial identity or facial emotion matching task. Analyses performed on posterior face specific EEG components revealed that mPFC-TMS reduced the P1-N1 component. In particular, only when an explicit expression processing was required, mPFC-TMS interacted with emotion type in relation to hemispheric side at different timing; the first P1-N1 component was affected in the right hemisphere whereas the later N1-P2 component was modulated in the left hemisphere. These findings support the hypothesis that the frontal cortex exerts an early influence on the occipital cortex during face processing and suggest a different timing of the right and left hemisphere involvement in emotion discrimination. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Left Activism, Succour and Selfhood

    DEFF Research Database (Denmark)

    Hughes, Celia Penelope

    2014-01-01

    an interchange of motherhood, domesticity, far-left politics, and close female friendship. The article will show how the women's epistolary friendship offers intimate insight into female self-fashioning at a breakthrough social and political moment in 1970s Britain. As they reflected on some of the key political...

  17. Neglecting the left side of a city square but not the left side of its clock: prevalence and characteristics of representational neglect.

    Directory of Open Access Journals (Sweden)

    Cecilia Guariglia

    Full Text Available Representational neglect, which is characterized by the failure to report left-sided details of a mental image from memory, can occur after a right hemisphere lesion. In this study, we set out to verify the hypothesis that two distinct forms of representational neglect exist, one involving object representation and the other environmental representation. As representational neglect is considered rare, we also evaluated the prevalence and frequency of its association with perceptual neglect. We submitted a group of 96 unselected, consecutive, chronic, right brain-damaged patients to an extensive neuropsychological evaluation that included two representational neglect tests: the Familiar Square Description Test and the O'Clock Test. Representational neglect, as well as perceptual neglect, was present in about one-third of the sample. Most patients neglected the left side of imagined familiar squares but not the left side of imagined clocks. The present data show that representational neglect is not a rare disorder and also support the hypothesis that two different types of mental representations (i.e. topological and non-topological images may be selectively damaged in representational neglect.

  18. Atypical category processing and hemispheric asymmetries in high-functioning children with autism: revealed through high-density EEG mapping.

    Science.gov (United States)

    Fiebelkorn, Ian C; Foxe, John J; McCourt, Mark E; Dumas, Kristina N; Molholm, Sophie

    2013-05-01

    Behavioral evidence for an impaired ability to group objects based on similar physical or semantic properties in autism spectrum disorders (ASD) has been mixed. Here, we recorded brain activity from high-functioning children with ASD as they completed a visual-target detection task. We then assessed the extent to which object-based selective attention automatically generalized from targets to non-target exemplars from the same well-known object class (e.g., dogs). Our results provide clear electrophysiological evidence that children with ASD (N=17, aged 8-13 years) process the similarity between targets (e.g., a specific dog) and same-category non-targets (SCNT) (e.g., another dog) to a lesser extent than do their typically developing (TD) peers (N=21). A closer examination of the data revealed striking hemispheric asymmetries that were specific to the ASD group. These findings align with mounting evidence in the autism literature of anatomic underconnectivity between the cerebral hemispheres. Years of research in individuals with TD have demonstrated that the left hemisphere (LH) is specialized toward processing local (or featural) stimulus properties and the right hemisphere (RH) toward processing global (or configural) stimulus properties. We therefore propose a model where a lack of communication between the hemispheres in ASD, combined with typical hemispheric specialization, is a root cause for impaired categorization and the oft-observed bias to process local over global stimulus properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Hemispheric asymmetry in event knowledge activation during incremental language comprehension: A visual half-field ERP study.

    Science.gov (United States)

    Metusalem, Ross; Kutas, Marta; Urbach, Thomas P; Elman, Jeffrey L

    2016-04-01

    During incremental language comprehension, the brain activates knowledge of described events, including knowledge elements that constitute semantic anomalies in their linguistic context. The present study investigates hemispheric asymmetries in this process, with the aim of advancing our understanding of the neural basis and functional properties of event knowledge activation during incremental comprehension. In a visual half-field event-related brain potential (ERP) experiment, participants read brief discourses in which the third sentence contained a word that was either highly expected, semantically anomalous but related to the described event (Event-Related), or semantically anomalous but unrelated to the described event (Event-Unrelated). For both visual fields of target word presentation, semantically anomalous words elicited N400 ERP components of greater amplitude than did expected words. Crucially, Event-Related anomalous words elicited a reduced N400 relative to Event-Unrelated anomalous words only with left visual field/right hemisphere presentation. This result suggests that right hemisphere processes are critical to the activation of event knowledge elements that violate the linguistic context, and in doing so informs existing theories of hemispheric asymmetries in semantic processing during language comprehension. Additionally, this finding coincides with past research suggesting a crucial role for the right hemisphere in elaborative inference generation, raises interesting questions regarding hemispheric coordination in generating event-specific linguistic expectancies, and more generally highlights the possibility of functional dissociation of event knowledge activation for the generation of elaborative inferences and for linguistic expectancies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Ideomotor Apraxia in Left Thalamic Hemorrhage: Discrepancy between Clinical Course and SPECT

    Directory of Open Access Journals (Sweden)

    Armin Schnider

    1991-01-01

    Full Text Available We present a patient who developed severe ideomotor apraxia (IA and subcortical aphasia after a hemorrhage involving the posterior part of the left thalamus and the posterior limb of the internal capsule. The cerebral blood flow (CBF of the left hemisphere as measured by 99Tc-HM-PAO SPECT was initially diminished as compared to the right hemisphere. The apraxia and aphasia eventually resolved. Despite this clinical improvement CBF of the left hemisphere worsened. Our findings do not support the view that apraxia and aphasia following lesion of deep subcortical structures is due to cortical derangement induced by disruption of unspecific activating thalamo-cortical pathways. The results call for caution in the functional interpretation of perfusion deficits detected by SPECT.

  1. Anarchy, socialism and a Darwinian left.

    Science.gov (United States)

    Clarke, Ellen

    2006-03-01

    In A Darwinian left Peter Singer aims to reconcile Darwinian theory with left wing politics, using evolutionary game theory and in particular a model proposed by Robert Axelrod, which shows that cooperation can be an evolutionarily successful strategy. In this paper I will show that whilst Axelrod's model can give support to a kind of left wing politics, it is not the kind that Singer himself envisages. In fact, it is shown that there are insurmountable problems for the idea of increasing Axelrodian cooperation within a welfare state. My surprising conclusion will be that a Darwinian left worthy of the name would be anarchistic.

  2. Calibration of fisheye lenses for hemispherical photography

    International Nuclear Information System (INIS)

    Diaci, J.; Kolar, U.

    2000-01-01

    Hemispherical photography represents one of the most appropriate methods of estimating averages of solar radiation over extended periods of time. This method is based upon the use of extremely wide-angle fisheye lenses, which produce large projection distortion. To correctly interpret hemispherical photography we have to know the projection characteristics of the fisheye lens in combination with a camera body. This can be achieved through lens calibration. The first part of the article explains in detail the calibration method for fisheye lenses which are used to assess the solar radiation in forest ecology research. In the second part the results of calibration for fisheye lens Sigma 8 mm, f/4 (MF, N) are presented. The lens was used on a Nikon F50 camera body

  3. Solar performance of hemispherical vault roofs

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Munoz, V.M. [Instituto Politecnico Nacional, La Paz, Baja California Sur (Mexico). Centro Interdisciplinario de Ciencias Marinas; Porta-Gandara, M.A. [Centro de Investigaciones Biologicas del Noroeste S.C., Baja California Sur (Mexico); Heard, C. [Instituto Mexinano de Petroleo (Mexico)

    2003-12-01

    In hot climates, the improvement of comfort by passive solar techniques is a very important issue. In many parts of the world such as the Middle East, vault roofs are widely used in construction. The solar and energy performance of a hemispherical vault roof is studied, including the auto-shading instant effect during several days for different latitudes and throughout the year also. The results are compared with the standard horizontal flat roofing used in the typical modern low-cost housing in Mexico. The hemispherical vault receives around 35% less energy than the flat roof between the equinoxes, besides having other advantages such as a greater ceiling height, natural ventilation and illumination possibilities, and structural stability. (author)

  4. On the hemisphere symmetry of reflected shortwave radiation

    OpenAIRE

    Voigt, A.; Stevens, B.; Bader, J.; Mauritsen, T.

    2013-01-01

    While the concentration of landmasses and atmospheric aerosols on the NorthernHemisphere suggests that the Northern Hemisphere is brighter than the Southern Hemisphere, satellite measurements of top-of-atmosphere irradiances found that both hemispheres reflect nearly the same amount of shortwave irradiance.Here, the authors document that the most precise and accurate observation, the energy balanced and filled dataset of the Clouds and the Earth’sRadiant Energy System covering the period 2000...

  5. An ensemble with the Chinese pentatonic scale using electroencephalogram from both hemispheres.

    Science.gov (United States)

    Wu, Dan; Li, Chao-Yi; Yao, De-Zhong

    2013-10-01

    To listen to brain activity as a piece of music, we previously proposed scale-free brainwave music (SFBM) technology, which translated the scalp electroencephalogram (EEG) into musical notes according to the power law of both the EEG and music. In this study, the methodology was further extended to ensemble music on two channels from the two hemispheres. EEG data from two channels symmetrically located on the left and right hemispheres were translated into MIDI sequences by SFBM, and the EEG parameters modulated the pitch, duration and volume of each note. Then, the two sequences were filtered into an ensemble with two voices: the pentatonic scale (traditional Chinese music) or the heptatonic scale (standard Western music). We demonstrated differences in harmony between the two scales generated at different sleep stages, with the pentatonic scale being more harmonious. The harmony intervals of this brain ensemble at various sleep stages followed the power law. Compared with the heptatonic scale, it was easier to distinguish the different stages using the pentatonic scale. These results suggested that the hemispheric ensemble can represent brain activity by variations in pitch, tempo and harmony. The ensemble with the pentatonic scale sounds more consonant, and partially reflects the relations of the two hemispheres. This can be used to distinguish the different states of brain activity and provide a new perspective on EEG analysis.

  6. Hemispheric connectivity and the visual-spatial divergent-thinking component of creativity.

    Science.gov (United States)

    Moore, Dana W; Bhadelia, Rafeeque A; Billings, Rebecca L; Fulwiler, Carl; Heilman, Kenneth M; Rood, Kenneth M J; Gansler, David A

    2009-08-01

    Divergent thinking is an important measurable component of creativity. This study tested the postulate that divergent thinking depends on large distributed inter- and intra-hemispheric networks. Although preliminary evidence supports increased brain connectivity during divergent thinking, the neural correlates of this characteristic have not been entirely specified. It was predicted that visuospatial divergent thinking would correlate with right hemisphere white matter volume (WMV) and with the size of the corpus callosum (CC). Volumetric magnetic resonance imaging (MRI) analyses and the Torrance Tests of Creative Thinking (TTCT) were completed among 21 normal right-handed adult males. TTCT scores correlated negatively with the size of the CC and were not correlated with right or, incidentally, left WMV. Although these results were not predicted, perhaps, as suggested by Bogen and Bogen (1988), decreased callosal connectivity enhances hemispheric specialization, which benefits the incubation of ideas that are critical for the divergent-thinking component of creativity, and it is the momentary inhibition of this hemispheric independence that accounts for the illumination that is part of the innovative stage of creativity. Alternatively, decreased CC size may reflect more selective developmental pruning, thereby facilitating efficient functional connectivity.

  7. Long-term variability in Northern Hemisphere snow cover and associations with warmer winters

    Science.gov (United States)

    McCabe, Gregory J.; Wolock, David M.

    2010-01-01

    A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of estimated Northern Hemisphere March SCA shows a substantial decrease since about 1970, and this decrease corresponds to an increase in mean winter Northern Hemisphere temperature. The increase in winter temperature has caused a decrease in the fraction of precipitation that occurs as snow and an increase in snowmelt for some parts of the Northern Hemisphere, particularly the mid-latitudes, thus reducing snow packs and March SCA. In addition, the increase in winter temperature and the decreases in SCA appear to be associated with a contraction of the circumpolar vortex and a poleward movement of storm tracks, resulting in decreased precipitation (and snow) in the low- to mid-latitudes and an increase in precipitation (and snow) in high latitudes. If Northern Hemisphere winter temperatures continue to warm as they have since the 1970s, then March SCA will likely continue to decrease.

  8. How to engage the right brain hemisphere in aphasics without even singing: evidence for two paths of speech recovery

    OpenAIRE

    Stahl, Benjamin; Henseler, Ilona; Turner, Robert; Geyer, Stefan; Kotz, Sonja A.

    2013-01-01

    There is an ongoing debate as to whether singing helps left-hemispheric stroke patients recover from non-fluent aphasia through stimulation of the right hemisphere. According to recent work, it may not be singing itself that aids speech production in non-fluent aphasic patients, but rhythm and lyric type. However, the long-term effects of melody and rhythm on speech recovery are largely unknown. In the current experiment, we tested 15 patients with chronic non-fluent aphasia who underwent eit...

  9. Recent climate changes in the northern hemisphere

    International Nuclear Information System (INIS)

    Trenberth, K.E.

    1990-01-01

    The consistency of analyzed changes in surface wind stress, sea level pressures and surface temperatures between 1980-86 and previous periods indicates the reality of statistically significant and substantial climate changes in the Northern Hemisphere, especially over the North Pacific, on decadal time scales. Cooling in North Pacific sea surface temperatures and warming along the west coast of North America and Alaska are ascribed mainly to the changes in thermal advection associated with a deeper and more extensive Aleutian Low

  10. Left atrial volume index

    DEFF Research Database (Denmark)

    Poulsen, Mikael K; Dahl, Jordi S; Henriksen, Jan Erik

    2013-01-01

    To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease.......To determine the prognostic importance of left atrial (LA) dilatation in patients with type 2 diabetes (T2DM) and no history of cardiovascular disease....

  11. Hemispherical optical dome for underwater communication

    Science.gov (United States)

    Shiri, Ron S.; Lunde, Emily L.; Coronado, Patrick L.; Quijada, Manuel A.

    2017-08-01

    For many years, acoustic systems have been used as the primary method for underwater communication; however, the data transfer rate of such systems is low because sound propagates slowly through water. A higher throughput can be achieved using visible light to transmit data underwater. The first issue with this approach is that there is generally a large loss of the light signal due to scattering and absorption in water, even though there is an optimal wavelength for transmission in the blue or green wavelengths of the visible spectrum. The second issue is that a simple communication system, consisting only of a highly directional source/transmitter and small optical detector/receiver, has a very narrow field of view. The goal of this project is to improve an optical, underwater communication system by increasing the effective field of view of the receiving optics. To this end, we make two changes to the simple system: (1) An optical dome was added near the receiver. An array of lenses is placed radially on the surface of the dome, reminiscent of the compound eye of an insect. The lenses make the source and detector planes conjugate, and each lens adds a new region of the source plane to the instrument's total field of view. (2) The receiver was expanded to include multiple photodiodes. With these two changes, the receiver has much more tolerance to misalignments (in position and angle) of the transmitter. Two versions of the optical dome (with 6" and 8" diameters) were designed using PTC's Creo CAD software and modeled using Synopsys' CODE V optical design software. A series of these transparent hemispherical domes, with both design diameters, were manufactured using a 5-axis mill. The prototype was then retrofitted with lenses and compared with the computer-generated model to demonstrate the effectiveness of this solution. This work shows that the dome design improves the optical field of view of the underwater communication system considerably. Furthermore, with

  12. Tool-Use and the Left Hemisphere: What Is Lost in Ideomotor Apraxia?

    Science.gov (United States)

    Sunderland, Alan; Wilkins, Leigh; Dineen, Rob; Dawson, Sophie E.

    2013-01-01

    Impaired tool related action in ideomotor apraxia is normally ascribed to loss of sensorimotor memories for habitual actions (engrams), but this account has not been tested against a hypothesis of a general deficit in representation of hand-object spatial relationships. Rapid reaching for familiar tools was compared with reaching for abstract…

  13. Psychological Correlates of Handedness and Corpus Callosum Asymmetry in Autism: The Left Hemisphere Dysfunction Theory Revisited

    Science.gov (United States)

    Floris, Dorothea L.; Chura, Lindsay R.; Holt, Rosemary J.; Suckling, John; Bullmore, Edward T.; Baron-Cohen, Simon; Spencer, Michael D.

    2013-01-01

    Rightward cerebral lateralization has been suggested to be involved in the neuropathology of autism spectrum conditions. We investigated functional and neuroanatomical asymmetry, in terms of handedness and corpus callosum measurements in male adolescents with autism, their unaffected siblings and controls, and their associations with executive…

  14. Neuroplasticity of language in left-hemisphere stroke: Evidence linking subsecond electrophysiology and structural connections

    NARCIS (Netherlands)

    Piai, V.; Meyer, L.; Dronkers, N.F.; Knight, R.T.

    2017-01-01

    The understanding of neuroplasticity following stroke is predominantly based on neuroimaging measures that cannot address the subsecond neurodynamics of impaired language processing. We combined behavioral and electrophysiological measures and structural-connectivity estimates to characterize

  15. Transpolar arcs observed simultaneously in both hemispheres

    Science.gov (United States)

    Carter, J. A.; Milan, S. E.; Fear, R. C.; Walach, M.-T.; Harrison, Z. A.; Paxton, L. J.; Hubert, B.

    2017-06-01

    Two coexisting transpolar arcs are observed on 31 August 2005. We track the formation and motion of the arcs in both the Northern and Southern Hemispheres, using data from two independent satellites (Imager for Magnetopause to Aurora Global Exploration and a Defence Meteorological Satellite Program satellite). The observations are supported by supplementary ground-based ionospheric convection data from the Super Dual Auroral Radar Network. The two arcs form during a period of northward interplanetary magnetic field. Following a change in the direction of the interplanetary magnetic field BY component from negative to positive, the dawnside arc traverses the polar cap to the duskside in the Northern Hemisphere. Over the same time period and in the Southern Hemisphere, the duskside arc traverses the polar cap to the dawnside. A complex magnetic field line topology resulting in the coexistence of two tongues of closed field lines protruding into the otherwise open polar cap is implied. We discuss these observations in terms of magnetic conjugacy and a model of transpolar arcs formation.

  16. Task difficulty reduces the left visual hemispace bias for judgments of emotion in chimeric faces.

    Science.gov (United States)

    Carbary, Timothy J; Almerigi, Jason B; Harris, Lauren Julius

    2002-01-01

    A prior study (Carbary, Almerigi, & Harris, 2001) of adults' judgments of emotional chimeric faces showed that the left visual hemispace (LVH) bias normally found on a free-viewing chimeric faces test is reduced when the task is judged to be difficult. Taking into account theory and research on hemispheric differences in styles, or strategies, of information processing, we proposed that the reduction was related to a change in these strategies. Two new experiments are presented that independently manipulate task difficulty and show the same task difficulty-related effect as in our prior study. Data are also presented suggesting that the strategy most commonly adopted for difficult judgments is part-based or feature-oriented, whereas the strategy most commonly adopted for easy judgments is reliance on "first impression."

  17. Lateralization of spatial rather than temporal attention underlies the left hemifield advantage in rapid serial visual presentation.

    Science.gov (United States)

    Asanowicz, Dariusz; Kruse, Lena; Śmigasiewicz, Kamila; Verleger, Rolf

    2017-11-01

    In bilateral rapid serial visual presentation (RSVP), the second of two targets, T1 and T2, is better identified in the left visual field (LVF) than in the right visual field (RVF). This LVF advantage may reflect hemispheric asymmetry in temporal attention or/and in spatial orienting of attention. Participants performed two tasks: the "standard" bilateral RSVP task (Exp.1) and its unilateral variant (Exp.1 & 2). In the bilateral task, spatial location was uncertain, thus target identification involved stimulus-driven spatial orienting. In the unilateral task, the targets were presented block-wise in the LVF or RVF only, such that no spatial orienting was needed for target identification. Temporal attention was manipulated in both tasks by varying the T1-T2 lag. The results showed that the LVF advantage disappeared when involvement of stimulus-driven spatial orienting was eliminated, whereas the manipulation of temporal attention had no effect on the asymmetry. In conclusion, the results do not support the hypothesis of hemispheric asymmetry in temporal attention, and provide further evidence that the LVF advantage reflects right hemisphere predominance in stimulus-driven orienting of spatial attention. These conclusions fit evidence that temporal attention is implemented by bilateral parietal areas and spatial attention by the right-lateralized ventral frontoparietal network. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The Colombian Left: A Paradoxical Past; A Promising Future?

    Directory of Open Access Journals (Sweden)

    Charles Bergquist

    2017-07-01

    Full Text Available The essay explores the paradoxical history of the left in Colombia: how and why one of the weakest lefts in Latin America brought about the strongest and most lasting Marxist insurrection in the hemisphere in the decades following the Cuban Revolution. The article argues that the terms of this paradox are related, that the historic weakness of the left partly explains the force and longevity of revolutionary guerrillas, and that said paradox helps clarify not only the failure of several attempts to achieve a negotiated settlement of the armed conflict, but also the negative vote in the October 2016 plebiscite. Finally, it envisions a more promising future for the country’s left, provided that a lasting peace is consolidated.

  19. Hemispatial Neglect Shows That “Before” Is “Left”

    Directory of Open Access Journals (Sweden)

    Mario Bonato

    2016-01-01

    Full Text Available Recent research has led to the hypothesis that events which unfold in time might be spatially represented in a left-to-right fashion, resembling writing direction. Here we studied fourteen right-hemisphere damaged patients, with or without neglect, a disorder of spatial awareness affecting contralesional (here left space processing and representation. We reasoned that if the processing of time-ordered events is spatial in nature, it should be impaired in the presence of neglect and spared in its absence. Patients categorized events of a story as occurring before or after a central event, which acted as a temporal reference. An asymmetric distance effect emerged in neglect patients, with slower responses to events that took place before the temporal reference. The event occurring immediately before the reference elicited particularly slow responses, closely mirroring the pattern found in neglect patients performing numerical comparison tasks. Moreover, the first item elicited significantly slower responses than the last one, suggesting a preference for a left-to-right scanning/representation of events in time. Patients without neglect showed a regular and symmetric distance effect. These findings further suggest that the representation of events order is spatial in nature and provide compelling evidence that ordinality is similarly represented within temporal and numerical domains.

  20. Altered Amygdala Resting-State Functional Connectivity and Hemispheric Asymmetry in Patients With Social Anxiety Disorder

    Directory of Open Access Journals (Sweden)

    Ye-Ha Jung

    2018-04-01

    Full Text Available Background: The amygdala plays a key role in emotional hyperreactivity in response to social threat in patients with social anxiety disorder (SAD. We investigated resting-state functional connectivity (rs-FCN of the left and right amygdala with various brain regions and functional lateralization in patients with SAD.Methods: A total of 36 patients with SAD and 42 matched healthy controls underwent functional magnetic resonance imaging (fMRI at rest. Using the left and right amygdala as seed regions, we compared the strength of the rs-FCN in the patient and control groups. Furthermore, we investigated group differences in the hemispheric asymmetry of the functional connectivity maps of the left and right amygdala.Results: Compared with healthy controls, the rs-FCN between the left amygdala and the dorsolateral prefrontal cortex was reduced in patients with SAD, whereas left amygdala connectivity with the fusiform gyrus, anterior insula, supramarginal gyrus, and precuneus was increased or positively deflected in the patient group. Additionally, the strength rs-FCN between the left amygdala and anterior insula was positively associated with the severity of the fear of negative evaluation in patients with SAD (r = 0.338, p = 0.044. The rs-FCN between the right amygdala and medial frontal gyrus was decreased in patients with SAD compared with healthy controls, whereas connectivity with the parahippocampal gyrus was greater in the patient group than in the control group. The hemispheric asymmetry patterns in the anterior insula, intraparietal sulcus (IPS, and inferior frontal gyrus of the patient group were opposite those of the control group, and functional lateralization of the connectivity between the amygdala and the IPS was associated with the severity of social anxiety symptoms (r = 0.365, p = 0.037.Conclusion: Our findings suggest that in addition to impaired fronto-amygdala communication, the functional lateralization of amygdala function

  1. Fabrication and electrochemical properties of hemisphere structured 3D Li(Li0.2Mn0.54Co0.13Ni0.13)O2 cathode thin film for all-solid-state lithium battery.

    Science.gov (United States)

    Yim, H; Kong, W Y; Yoon, S J; Kim, Y C; Choi, J W

    2013-05-01

    The Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode thin films were deposited on planar, hemisphere, linked hemisphere, and isolated hemisphere structured Pt current collector thin films to investigate the effect of 3-dimensional (3-D) structure for the electrochemical properties of active cathode thin films. The films of linked hemisphere structure shows the highest initial discharge capacity of 140 microA h/cm2-microm which is better than those of planar (62 microA h/cm2-microm), hemisphere (94.6 microA h/cm2-microm), and isolated hemisphere (135 microA h/cm2-microm) films due to increase of surface area for cathode thin films. Linked hemisphere shows the biggest capacity and the best retention rate because 6 nanobridges of each hemisphere bring strong connection.

  2. Dependence of thermospheric zonal winds on solar flux, geomagnetic activity, and hemisphere as measured by CHAMP

    Science.gov (United States)

    Zhang, Xiaofang; Liu, Libo; Liu, Songtao

    2017-08-01

    The thermospheric zonal winds measured by the CHAllenging Minisatellite Payload (CHAMP) satellite are used to statistically determine the climatology under quiet and active geomagnetic conditions. By collectively analyzing the bin-averaged wind trend with F10.7 and the solar-induced difference in wind structures, the solar flux dependence of global thermosphere zonal wind is determined. The increase of solar flux enhances the eastward winds at low latitudes from dusk to midnight. The increased ion drag reduces the nighttime eastward wind in the subauroral latitudes, and the daytime westward winds from 06 to 08 MLT at all latitudes decrease with increasing solar flux. Zonal winds show coupled seasonal/extreme ultraviolet (EUV) dependency. The equatorial zonal winds from 18 to 04 magnetic local time (MLT) indicate weaker eastward winds during the June solstice at high solar flux levels. Quiet time eastward winds at subauroral latitudes from 16 to 20 MLT are further decreased in the winter hemisphere. Influenced by asymmetries in solar illumination and the magnetic field, zonal winds show hemispheric asymmetries. Quiet daytime winds are additionally influenced by solar illumination effects, and the westward winds at the middle and subauroral latitudes are always stronger in the summer. The nighttime eastward winds are higher in the winter hemisphere during the solstices, as in the Southern Hemisphere during equinoxes, with the winter-summer asymmetry lessened or receding at the solar maxima. Storm-induced subauroral westward disturbance winds are higher in the summer hemisphere and in the Northern Hemisphere during equinoxes. At a high level of solar flux, the westward disturbance winds are comparable in the two hemispheres during December solstice. Geomagnetic disturbance wind observations from CHAMP agree well with the empirical geomagnetic disturbance wind model, except for stronger subauroral westward jets. Westward winds during the afternoon may be enhanced in

  3. Task activation and functional connectivity show concordant memory laterality in temporal lobe epilepsy.

    Science.gov (United States)

    Sideman, Noah; Chaitanya, Ganne; He, Xiaosong; Doucet, Gaelle; Kim, Na Young; Sperling, Michael R; Sharan, Ashwini D; Tracy, Joseph I

    2018-04-01

    In epilepsy, asymmetries in the organization of mesial temporal lobe (MTL) functions help determine the cognitive risk associated with procedures such as anterior temporal lobectomy. Past studies have investigated the change/shift in a visual episodic memory laterality index (LI) in mesial temporal lobe structures through functional magnetic resonance imaging (fMRI) task activations. Here, we examine whether underlying task-related functional connectivity (FC) is concordant with such standard fMRI laterality measures. A total of 56 patients with temporal lobe epilepsy (TLE) (Left TLE [LTLE]: 31; Right TLE [RTLE]: 25) and 34 matched healthy controls (HC) underwent fMRI scanning during performance of a scene encoding task (SET). We assessed an activation-based LI of the hippocampal gyrus (HG) and parahippocampal gyrus (PHG) during the SET and its correspondence with task-related FC measures. Analyses involving the HG and PHG showed that the patients with LTLE had a consistently higher LI (right-lateralized) than that of the HC and group with RTLE, indicating functional reorganization. The patients with RTLE did not display a reliable contralateral shift away from the pathology, with the mesial structures showing quite distinct laterality patterns (HG, no laterality bias; PHG, no evidence of LI shift). The FC data for the group with LTLE provided confirmation of reorganization effects, revealing that a rightward task LI may be based on underlying connections between several left-sided regions (middle/superior occipital and left medial frontal gyri) and the right PHG. The FCs between the right HG and left anterior cingulate/medial frontal gyri were also observed in LTLE. Importantly, the data demonstrate that the areas involved in the LTLE task activation shift to the right hemisphere showed a corresponding increase in task-related FCs between the hemispheres. Altered laterality patterns based on mesial temporal lobe epilepsy (MTLE) pathology manifest as several

  4. Left heart catheterization

    Science.gov (United States)

    Catheterization - left heart ... to help guide the catheters up into your heart and arteries. Dye (sometimes called "contrast") will be ... in the blood vessels that lead to your heart. The catheter is then moved through the aortic ...

  5. Assessment of the hemispheric lateralization of grapheme-color synesthesia with Stroop-type tests.

    Directory of Open Access Journals (Sweden)

    Mathieu J Ruiz

    Full Text Available Grapheme-color synesthesia, the idiosyncratic, arbitrary association of colors to letters or numbers, develops in childhood once reading is mastered. Because language processing is strongly left-lateralized in most individuals, we hypothesized that grapheme-color synesthesia could be left-lateralized as well. We used synesthetic versions of the Stroop test with colored letters and numbers presented either in the right or the left visual field of thirty-four synesthetes. Interference by synesthetic colors was stronger for stimuli in the right hemifield (first experiment, color naming task. Synesthetes were also faster in the right hemifield when naming the synesthetic color of graphemes (second experiment. Overall, the lateralization effect was 7 ms (the 95% confidence interval was [1.5 12] ms, a delay compatible with an additional callosal transfer for stimuli presented in the left hemifield. Though weak, this effect suggests that the association of synesthetic colors to graphemes may be preferentially processed in the left hemisphere. We speculate that this left-lateralization could be a landmark of synesthetic grapheme-color associations, if not found for color associations learnt by non-synesthete adults.

  6. Hemispherical Capsule Implosions for Fast Ignition*

    Science.gov (United States)

    Hanson, D. L.; Vesey, R. A.; Sinars, D. B.; Adams, R. G.; Cuneo, M. E.; Porter, J. L.; Slutz, S. A.; Johnston, R. R.; Wenger, D. F.; Schroen, D. G.

    2003-10-01

    The fast ignitor approach to ICF ignition separates the fuel assembly and fast heating processes. After compressing the fuel with the main driver, the fuel is ignited using a focused electron or ion beam generated by a fast, ultra-high power laser pulse. This significantly relaxes the drive symmetry, energy, and shock timing requirements compared to hot spot ignition. A hemispherical capsule target is a fast ignitor geometry well-adapted to symmetric fuel compression by a single-ended z-pinch radiation drive. The hemispherical capsule implodes radially, constrained at its equator by a flat high-density surface (a special case of the spherical capsule "cone-focus" geometry). This glide plane is mounted on a hollow pedestal that provides a plasma-free, short-pulse laser path to the compressed fuel core region. In experiments on the Z accelerator at Sandia, we are studying implosions of 2.0-mm-diameter, 60-micron-thick hemispherical capsules in cylindrical secondary hohlraums heated to 90-100 eV from one end by a 120 TW wire-array z-pinch. Analysis of ZBL 6.7 keV point-projection backlighter images of pole-hot implosions in a tall secondary and 6.18 keV monochromatic crystal backlighter images of more symmetric implosions in a short secondary will be presented. We will also discuss progress on the development of a cryogenic liquid fuel target for this fast ignitor compression geometry. * Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  7. Hemispheric differences in language processing in autism spectrum disorders: A meta-analysis of neuroimaging studies.

    Science.gov (United States)

    Herringshaw, Abbey J; Ammons, Carla J; DeRamus, Thomas P; Kana, Rajesh K

    2016-10-01

    Language impairments, a hallmark feature of autism spectrum disorders (ASD), have been related to neuroanatomical and functional abnormalities. Abnormal lateralization of the functional language network, increased reliance on visual processing areas, and increased posterior brain activation have all been reported in ASD and proposed as explanatory models of language difficulties. Nevertheless, inconsistent findings across studies have prevented a comprehensive characterization of the functional language network in ASD. The aim of this study was to quantify common and consistent patterns of brain activation during language processing in ASD and typically developing control (TD) participants using a meta-analytic approach. Activation likelihood estimation (ALE) meta-analysis was used to examine 22 previously published functional Magnetic Resonance Imaging (fMRI)/positron emission tomography studies of language processing (ASD: N = 328; TD: N = 324). Tasks included in this study addressed semantic processing, sentence comprehension, processing figurative language, and speech production. Within-group analysis showed largely overlapping patterns of language-related activation in ASD and TD groups. However, the ASD participants, relative to TD participants, showed: (1) more right hemisphere activity in core language areas (i.e., superior temporal gyrus and inferior frontal gyrus), particularly in tasks where they had poorer performance accuracy; (2) bilateral MTG hypo-activation across many different paradigms; and (3) increased activation of the left lingual gyrus in tasks where they had intact performance. These findings show that the hypotheses reviewed here address the neural and cognitive aspects of language difficulties in ASD across all tasks only in a limited way. Instead, our findings suggest the nuances of language and brain in ASD in terms of its context-dependency. Autism Res 2016, 9: 1046-1057. © 2016 International Society for Autism Research, Wiley

  8. The genus Platychara from the Western Hemisphere

    Science.gov (United States)

    Peck, R.E.; Forester, R.M.

    1979-01-01

    The systematics of four species belonging to the genus Platychara (Charophyta) from the Western Hemisphere is discussed. Three of the species, as defined herein, occur in Cretaceous and Paleocene rocks from Mexico through South America. The type species, P. compressa (Peck and Reker) Grambast, also of Cretaceous and Paleocene age, is herein restricted to deposits north of Mexico. These latter restrictions geographically separate P. compressa and P. perlata as presently defined but the relationship between these two species is still uncertain. A new species, P. grambastii, is proposed for specimens from Maestrichtian sediments in Jamaica. ?? 1979.

  9. Psychopathological manifestations of multiple meningiomas in the right hemisphere

    Directory of Open Access Journals (Sweden)

    A. A. Lukshina

    2015-01-01

    Full Text Available The paper gives the data available in the literature on meningiomas and their psychopathological manifestations that occupy a central position in the clinical picture in almost every 5 patients with these tumors. The authors provide a clinical and psychopathological analysis of a female patient with multiple meningiomas in the right hemisphere: a giant meningioma in the posterior third of the falx, a large meningioma in the temporal region, and three small meningiomas in the frontal and parietal regions. The disease started as headache; however, psychopathological symptoms remained missed by physicians, such as emotional lability; personality changes leading to family dissension; lower criticism; spatial orientation problems; hypomnesia; left-sided visual inattention,occurred in parallel. Surgical treatment was performed by stages: the two largest meningiomas were removed at an 11-day interval, which presented a means of observing psychopathological changes after each operation. It is concluded that greater attention should be given to the psychopathological manifestations of the disease, which is important to make a primary diagnosis and to define further treatment policy.

  10. Comparing forward and inverse models to estimate the seasonal variation of hemisphere-integrated fluxes of carbonyl sulfide

    Directory of Open Access Journals (Sweden)

    A. J. Kettle

    2002-01-01

    Full Text Available A simple inverse model is proposed to deduce hemisphere-integrated COS flux based on published time series of total column COS. The global atmosphere is divided into two boxes representing the Northern and Southern Hemispheres, and the total column COS data from several stations are used to calculate hemispheric COS loadings. The integrated flux within each hemisphere is calculated as a linear combination of a steady-state solution and time-varying perturbation. The nature of the time-varying perturbation is deduced using two different approaches: an analytic solution based on a cosine function that was fitted to the original total column COS measurement time series and a Simplex optimization with no underlying assumption about the functional form of the total column time series. The results suggest that there is a steady-state COS flux from the Northern to the Southern Hemisphere. There is a seasonal variation superimposed on this flux that in the Southern Hemisphere has a maximum rate of COS input into the atmosphere around January and a maximum rate of COS removal from the atmosphere around August--September. In the Northern Hemisphere, the maximum rate of COS input into the atmosphere is around May--June, and the maximum rate of COS removal is either August or January, depending on which station in the Northern Hemisphere is considered. The results of the inverse model are compared with the outcome of a forward approach on the temporal and spatial variation of the dominant global sources and sinks published earlier. In general, the deduced hemisphere-integrated flux estimates showed good agreement with the database estimates, though it remains uncertain whether COS removal from the atmosphere in the Northern Hemisphere is dominated by plant and soil uptake in the boreal summer or by oceanic uptake in boreal winter.

  11. Functional MRI evaluation of supplementary motor area language dominance in right- and left-handed subjects.

    Science.gov (United States)

    Dalacorte, Amauri; Portuguez, Mirna Wetters; Maurer das Neves, Carlos Magno; Anes, Maurício; Dacosta, Jaderson Costa

    2012-01-01

    Functional magnetic resonance imaging (fMRI) is a non-invasive brain imaging technique widely used in the evaluation of the brain function that provides images with high temporal and spatial resolution. Investigation of the supplementary motor area (SMA) function is critical in the pre-surgical evaluation of neurological patients, since marked individual differences and complex overlapping with adjacent cortical areas exist, and it is important to spare the SMA from lesions when adjacent cortical tissue is surgically removed. We used fMRI to assess the activity of SMA in six right-handed and six left-handed healthy volunteers when a task requiring silent repetition of a series of words was given. Brain activation areas in each of the subjects were localized according to the standard Talairach coordinate space, and the individual voxels for each map were compared after 3D sagittal images were created and SMA was delimited. Quantitative analysis of hemispheric and bilateral SMA activation was described as mean ± standard deviation of hot points/total points. The results show that the language task induced bilateral SMA activation. Left SMA activation was significantly higher than right SMA activation in both right-handed and left-handed subjects.

  12. The Left, The Better: White-Matter Brain Integrity Predicts Foreign Language Imitation Ability.

    Science.gov (United States)

    Vaquero, Lucía; Rodríguez-Fornells, Antoni; Reiterer, Susanne M

    2017-08-01

    Speech imitation is crucial for language acquisition and second-language learning. Interestingly, large individual differences regarding the ability in imitating foreign-language sounds have been observed. The origin of this interindividual diversity remains unknown, although it might be partially explained by structural predispositions. Here we correlated white-matter structural properties of the arcuate fasciculus (AF) with the performance of 52 German-speakers in a Hindi sentence- and word-imitation task. First, a manual reconstruction was performed, permitting us to extract the mean values along the three branches of the AF. We found that a larger lateralization of the AF volume toward the left hemisphere predicted the performance of our participants in the imitation task. Second, an automatic reconstruction was carried out, allowing us to localize the specific region within the AF that exhibited the largest correlation with foreign language imitation. Results of this reconstruction also showed a left lateralization trend: greater fractional anisotropy values in the anterior half of the left AF correlated with the performance in the Hindi-imitation task. From the best of our knowledge, this is the first time that foreign language imitation aptitude is tested using a more ecological imitation task and correlated with DTI tractography, using both a manual and an automatic method. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Effects of spatial attention on motion discrimination are greater in the left than right visual field.

    Science.gov (United States)

    Bosworth, Rain G; Petrich, Jennifer A F; Dobkins, Karen R

    2012-01-01

    In order to investigate differences in the effects of spatial attention between the left visual field (LVF) and the right visual field (RVF), we employed a full/poor attention paradigm using stimuli presented in the LVF vs. RVF. In addition, to investigate differences in the effects of spatial attention between the dorsal and ventral processing streams, we obtained motion thresholds (motion coherence thresholds and fine direction discrimination thresholds) and orientation thresholds, respectively. The results of this study showed negligible effects of attention on the orientation task, in either the LVF or RVF. In contrast, for both motion tasks, there was a significant effect of attention in the LVF, but not in the RVF. These data provide psychophysical evidence for greater effects of spatial attention in the LVF/right hemisphere, specifically, for motion processing in the dorsal stream. Published by Elsevier Ltd.

  14. Noninvasive brain stimulation for treatment of right- and left-handed poststroke aphasics.

    Science.gov (United States)

    Heiss, Wolf-Dieter; Hartmann, Alexander; Rubi-Fessen, Ilona; Anglade, Carole; Kracht, Lutz; Kessler, Josef; Weiduschat, Nora; Rommel, Thomas; Thiel, Alexander

    2013-01-01

    Accumulating evidence from single case studies, small case series and randomized controlled trials seems to suggest that inhibitory noninvasive brain stimulation (NIBS) over the contralesional inferior frontal gyrus (IFG) of right-handers in conjunction with speech and language therapy (SLT) improves recovery from poststroke aphasia. Application of inhibitory NIBS to improve recovery in left-handed patients has not yet been reported. A total of 29 right-handed subacute poststroke aphasics were randomized to receive either 10 sessions of SLT following 20 min of inhibitory repetitive transcranial magnetic stimulation (rTMS) over the contralesional IFG or 10 sessions of SLT following sham stimulation; 2 left-handers were treated according to the same protocol with real rTMS. Language activation patterns were assessed with positron emission tomography prior to and after the treatment; 95% confidence intervals for changes in language performance scores and the activated brain volumes in both hemispheres were derived from TMS- and sham-treated right-handed patients and compared to the same parameters in left-handers. Right-handed patients treated with rTMS showed better recovery of language function in global aphasia test scores (t test, p left-handed patients also improved, with 1 patient within the confidence limits of TMS-treated right-handers (23 points, 15.9-28.9) and the other patient within the limits of sham-treated subjects (8 points, 2.8-14.5). Both patients exhibited only a very small interhemispheric shift, much less than expected in TMS-treated right-handers, and more or less consolidated initially active networks in both hemispheres. Inhibitory rTMS over the nondominant IFG appears to be a safe and effective treatment for right-handed poststroke aphasics. In the 2 cases of left-handed aphasics no deterioration of language performance was observed with this protocol. However, therapeutic efficiency is less obvious and seems to be more related to the

  15. Reduced contralateral hemispheric flow measured by SPECT in cerebellar lesions

    International Nuclear Information System (INIS)

    Soenmezoglu, K.; Sperling, B.; Lassen, N.A.; Henriksen, T.; Tfelt-Hansen, P.

    1993-01-01

    Four patients with clinical signs of cerebellar stroke were studied twice by SPECT using 99m Tc-HMPAO as a tracer for cerebral blood flow (CBF). When first scanned 6 to 22 days after onset, all had a region of very low CBF in the symptomatic cerebellar hemisphere, and a mild to moderate CBF reduction (average 10%) in contralateral hemispheric cortex. In all four cases clinical signs of unilateral cerebellar dysfunction were still present when rescanned 1 to 4 months later and the relative CBF decrease in the contralateral cortex of the forebrain also remained. The basal ganglia contralateral to the cerebellar lesion CBF showed variable alterations. A relative CBF decrease was seen in upper part of basal ganglia in all four cases, but it was not a constant phenomenon. A relative CBF increase in both early and late SPECT scans was seen at low levels of neostriatum in two cases. The remote CBF changes in cerebellar stroke seen in the forebrain are probably caused by reduced or abolished cerebellar output. The term ''Crossed Cerebral Diaschisis'' may be used to describe these CBF changes that would appear to reflect both decreased and increased neuronal activity. (au)

  16. The changes in relation of auditory and visual input activity between hemispheres analized in cartographic EEG in a child with hyperactivity syndrome

    Directory of Open Access Journals (Sweden)

    Radičević Zoran

    2015-01-01

    Full Text Available The paper discusses the changes in relations of visual and auditory inputs between the hemispheres in a child with hyperactive syndrome and its effects which may lead to better attention engagement in auditory and visual information analysis. The method included the use of cartographic EEG and clinical procedure in a 10-year-old boy with hyperactive syndrome and attention deficit disorder, who has theta dysfunction manifested in standard EEG. Cartographic EEG patterns was performed on NihonKohden Corporation, EEG - 1200K Neurofax apparatus in longitudinal bipolar electrode assembly schedule by utilizing10/20 International electrode positioning. Impedance was maintained below 5 kΩ, with not more than 1 kΩ differences between the electrodes. Lower filter was set at 0.53 Hz and higher filter at 35 Hz. Recording was performed in a quiet period and during stimulation procedures that include speech and language basis. Standard EEG and Neurofeedback (NFB treatment indicated higher theta load, alpha 2 and beta 1 activity measured in the cartographic EEG which was done after the relative failure of NFB treatment. After this, the NFB treatment was applied which lasted for six months, in a way that when the boy was reading, the visual input was enhanced to the left hemisphere and auditory input was reduced to the right hemisphere. Repeated EEG mapping analysis showed that there was a significant improvement, both in EEG findings as well as in attention, behavioural and learning disorders. The paper discusses some aspects of learning, attention and behaviour in relation to changes in the standard EEG, especially in cartographic EEG and NFB findings.

  17. Motor imagery cognitive network after left ischemic stroke: study of the patients during mental rotation task.

    Directory of Open Access Journals (Sweden)

    Jing Yan

    Full Text Available Although motor imagery could improve motor rehabilitation, the detailed neural mechanisms of motor imagery cognitive process of stroke patients, particularly from functional network perspective, remain unclear. This study investigated functional brain network properties in each cognitive sub-stage of motor imagery of stroke patients with ischemic lesion in left hemisphere to reveal the impact of stroke on the cognition of motor imagery. Both stroke patients and control subjects participated in mental rotation task, which includes three cognitive sub-stages: visual stimulus perception, mental rotation and response cognitive process. Event-related electroencephalograph was recorded and interdependence between two different cortical areas was assessed by phase synchronization. Both global and nodal properties of functional networks in three sub-stages were statistically analyzed. Phase synchronization of stroke patients significantly reduced in mental rotation sub-stage. Longer characteristic path length and smaller global clustering coefficient of functional network were observed in patients in mental rotation sub-stage which implied the impaired segregation and integration. Larger nodal clustering coefficient and betweenness in contralesional occipitoparietal and frontal area respectively were observed in patients in all sub-stages. In addition, patients also showed smaller betweenness in ipsilesional central-parietal area in response sub-stage. The compensatory effects on local connectedness and centrality indicated the neuroplasticity in contralesional hemisphere. The functional brain networks of stroke patients demonstrated significant alterations and compensatory effects during motor imagery.

  18. Left versus right nipple preference in free-ranging infant rhesus macaques (Macaca mulatta).

    Science.gov (United States)

    Jaffe, Benjamin D; Evans, Theodore A; Howell, Sue; Westergaard, Gregory C; Snoy, Philip J; Higley, J Dee

    2006-04-01

    The examination of nonhuman primate (NHP) lateralized behaviors may provide insight into the evolution of hemispheric specialization. This study examined nipple preference in 64 infant macaques in order to consider the ontogeny of lateralized behavior. We used a focal animal sampling method to record nipple contact during 15, 30-min observation sessions collected across each infant's first year of life. Using a lateralized behavior index (LBI) we calculated individual and population preferences (LBI=(R-L)/(R+L); "R"=mean right nipple contact, "L"=mean left nipple contact). Strength of preference was calculated as the absolute value of this score. Infants exhibited no population preference for a particular nipple, but showed a significant strength of preference that developed after 48 hr. Interestingly, successive siblings preferred the nipple not used by the previous infant. These findings suggest that nipple preference is guided by external stimuli, and that nipple preference during infancy may not be a behavioral representation of hemispheric specialization. Copyright (c) 2006 Wiley Periodicals, Inc.

  19. [A New Diagnostic Tool for Apraxia in Patients with Right-Hemisphere Stroke: The Revised Cologne Apraxia Screening (KAS-R)].

    Science.gov (United States)

    Wirth, K; Held, A; Kalbe, E; Kessler, J; Saliger, J; Karbe, H; Fink, G R; Weiss, P H

    2016-10-01

    The Cologne Apraxia Screening (KAS) was developed to diagnose apraxia following left-hemisphere (LH) stroke. The present study aims at developing a diagnostic tool for patients with right-hemisphere (RH) stroke (KAS-R) by modifying the test material of the KAS and reducing the test items based on psychometric analyses.A total of 100 patients with RH stroke and 77 healthy control participants were tested. Psychometric analyses led to the exclusion of 8 KAS items. The final KAS-R, consisting of 12 items, shows good internal consistency (α = 0.795) as well as high sensitivity (79.4 %) and specificity (84.4 %). Applying a cut-off value of ≤ 46 (out of 48) points, 39 RH stroke patients were diagnosed with apraxia. Significant correlations were found between the KAS-R and an imitation test as well as expert ratings, indicating high construct validity. The results suggest that the KAS-R is a reliable and valid diagnostic tool for apraxic deficits after RH stroke. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Multiple priming of lexically ambiguous and unambiguous targets in the cerebral hemispheres: the coarse coding hypothesis revisited.

    Science.gov (United States)

    Kandhadai, Padmapriya; Federmeier, Kara D

    2007-06-11

    The coarse coding hypothesis postulates that the cerebral hemispheres differ in their breadth of semantic activation, with the left hemisphere activating a narrow, focused semantic field and the right weakly activating a broader semantic field. In support of coarse coding, studies investigating priming for multiple senses of a lexically ambiguous word have reported a right hemisphere benefit. However, studies of mediated priming have failed to find a right hemisphere advantage for processing distantly linked, unambiguous words. To address this debate, the present study made use of a multiple priming paradigm in which two primes either converged onto the single meaning of an unambiguous, lexically associated target (LION-STRIPES-TIGER) or diverged onto different meanings of an ambiguous target (KIDNEY-PIANO-ORGAN). In two experiments, participants either made lexical decisions to lateralized targets (Experiment 1) or made a semantic relatedness judgment between primes and targets (Experiment 2). In both tasks, for both ambiguous and unambiguous triplets we found equivalent priming strengths and patterns across the two visual fields, counter to the predictions of the coarse coding hypothesis. Priming patterns further suggested that both hemispheres made use of lexical level representations in the lexical decision task and semantic representations in the semantic judgment task.

  1. What forgetting tells us about remembering: the influence of top-down control on hemispheric asymmetries in verbal memory.

    Science.gov (United States)

    Tat, Michael J; Azuma, Tamiko

    2015-01-01

    It has been suggested that left hemisphere (LH) advantages in verbal processing is due to superior top-down control of verbal information. It is not clear how top-down mechanisms affect the encoding and retrieval of verbal information from hemispheric memory and whether they only influence activation or also encompass the inhibition of verbal information. The directed forgetting method, in conjunction with divided visual field presentation, was used to examine the influence of top-down control mechanisms on hemispheric asymmetries in verbal memory. Participants were cued to remember or forget words. Cues were presented either simultaneously with targets or after a short delay. A recognition memory test using divided visual field presentation was then given. Response times (RTs) revealed effects of cue timing in the LH. With simultaneous cues, RTs were faster to "Remember" words compared to "Forget" words. With delayed cues, RTs for "Remember" and "Forget" words were equivalent. In the right hemisphere (RH), "Remember" words were consistently faster than "Forget" words, regardless of cue timing. These data provide evidence that top-down mechanisms influenced LH verbal memory retrieval more than RH verbal memory retrieval. Finally, there was little evidence to suggest the hemispheres differ in inhibitory processing.

  2. Pre-surgical evaluation of the cerebral tumor in the left language related areas by functional MRI

    International Nuclear Information System (INIS)

    Zou Zhitong; Ma Lin; Weng Xuchu

    2010-01-01

    Objective: To evaluate the application of combination of BOLD-fMRI and diffusion tensor tractography (DTT) in pre-operative evaluation of cerebral tumors located at the left language related areas. Methods: A non-vocal button pressing semantic judging paradigm was developed and validated in 10 right-handed volunteers at 3 T. After validation, this protocol combined with DTI were applied to 15 patients with left cerebral tumor prior to surgical resection, and 3 of them had aphasia. fMRI data analysis was on subject-specific basis by one-sampled t-test. The distance from the tumor to Broca area and pre-central 'hand-knot' area were measured separately. Functional language laterality index (LI) was calculated by taking out Broca area and Wernicke area. Three dimensional architecture of frontal lobe white matter fibers, especially arcuate fasciculus, were visualized using diffusion tensor tractography on Volume-one software. The images demonstrating relationship among tumor, language activation areas and white matter fibers were reviewed by neurosurgeons as part of pre-operative planning. One year after the operation, patients were followed up with MRI and language function test. Results: The non-vocal semantic judging paradigm successfully detect Broca area, Wernicke area and pre-central 'hand-knot' area. In 12 of 15 patients, the relationship of Broca area and pre-central motor area to the left brain tumor in language related areas was identified, which make the pre-operative neurosurgical plan applicable to minimize the disruption of language and motor. 8 patients had the left language dominant hemisphere, 3 patients with the right language dominant hemisphere and 1 patient with bilateral dominance. The other 3 patients' fMRI data were corrupted by patients' motion. Diffusion tensor images were corrupted by motion in 1 patient but demonstrated the impact of tumor on left accouter fasciculus in 14 patients. Diffusion tensor tractography showed disruption of left

  3. Descriptive anatomy of Heschl?s gyri in 430 healthy volunteers, including 198 left-handers

    OpenAIRE

    Marie, D.; Jobard, G.; Crivello, F.; Perchey, G.; Petit, L.; Mellet, E.; Joliot, M.; Zago, L.; Mazoyer, B.; Tzourio-Mazoyer, N.

    2013-01-01

    This study describes the gyrification patterns and surface areas of Heschl?s gyrus (HG) in 430 healthy volunteers mapped with magnetic resonance imaging. Among the 232 right-handers, we found a large occurrence of duplication (64?%), especially on the right (49 vs. 37?% on the left). Partial duplication was twice more frequent on the left than complete duplication. On the opposite, in the right hemisphere, complete duplication was 10?% more frequent than partial duplication. The most frequent...

  4. EEG Correlates of Preparatory Orienting, Contextual Updating, and Inhibition of Sensory Processing in Left Spatial Neglect.

    Science.gov (United States)

    Lasaponara, Stefano; D'Onofrio, Marianna; Pinto, Mario; Dragone, Alessio; Menicagli, Dario; Bueti, Domenica; De Lucia, Marzia; Tomaiuolo, Francesco; Doricchi, Fabrizio

    2018-04-11

    Studies with event-related potentials have highlighted deficits in the early phases of orienting to left visual targets in right-brain-damaged patients with left spatial neglect (N+). However, brain responses associated with preparatory orienting of attention, with target novelty and with the detection of a match/mismatch between expected and actual targets (contextual updating), have not been explored in N+. Here in a study in healthy humans and brain-damaged patients of both sexes we demonstrate that frontal activity that reflects supramodal mechanisms of attentional orienting (Anterior Directing Attention Negativity, ADAN) is entirely spared in N+. In contrast, posterior responses that mark the early phases of cued orienting (Early Directing Attention Negativity, EDAN) and the setting up of sensory facilitation over the visual cortex (Late Directing Attention Positivity, LDAP) are suppressed in N+. This uncoupling is associated with damage of parietal-frontal white matter. N+ also exhibit exaggerated novelty reaction to targets in the right side of space and reduced novelty reaction for those in the left side (P3a) together with impaired contextual updating (P3b) in the left space. Finally, we highlight a drop in the amplitude and latency of the P1 that over the left hemisphere signals the early blocking of sensory processing in the right space when targets occur in the left one: this identifies a new electrophysiological marker of the rightward attentional bias in N+. The heterogeneous effects and spatial biases produced by localized brain damage on the different phases of attentional processing indicate relevant functional independence among their underlying neural mechanisms and improve the understanding of the spatial neglect syndrome. SIGNIFICANCE STATEMENT Our investigation answers important questions: are the different components of preparatory orienting (EDAN, ADAN, LDAP) functionally independent in the healthy brain? Is preparatory orienting of

  5. Cerebral lateralization for the processing of spatial coordinates and categories in left-and right-handers.

    Science.gov (United States)

    LAENG, B; PETERS, M

    1995-04-01

    Subjects judged whether a tachistoscopially lateralized drawing was identical or different to a drawing seen immediately before in free vision. The drawings depicted natural objects (e.g. animals). On half of the trials the tachistoscopic drawing presented the same objects but either the categorical or the coordinate spatial relations (according to Kosslyn's definitions [23]) between the objects were transformed. In the first experiment 38 right-handed subjects (half males and half females) were tested. Categorical judgements were faster when the match drawing appeared in the right visual field, whereas coordinate judgements were faster when the match drawing appeared in the left visual field. In the second experiment 26 right-handed and 40 left-handed subjects participated. Almost all the subjects were female. Right-handed subjects replicated the findings of the subjects in the first experiment. However, the LHs did not show any difference in response times between spatial conditions and visual fields. These findings support Kosslyn's hypothesis that the left and right hemispheres are specialized respectively for processing categorical and coordinate spatial relations. Moreover, they also suggest that this lateralization pattern is not typical of left-handers.

  6. Hemispheric language dominance measured by repetitive navigated transcranial magnetic stimulation and postoperative course of language function in brain tumor patients.

    Science.gov (United States)

    Ille, Sebastian; Kulchytska, Nataliia; Sollmann, Nico; Wittig, Regina; Beurskens, Eva; Butenschoen, Vicki M; Ringel, Florian; Vajkoczy, Peter; Meyer, Bernhard; Picht, Thomas; Krieg, Sandro M

    2016-10-01

    The resection of left-sided perisylvian brain lesions harbors the risk of postoperative aphasia. Because it is known that language function can shift between hemispheres in brain tumor patients, the preoperative knowledge of the patient's language dominance could be helpful. We therefore investigated the hemispheric language dominance by repetitive navigated transcranial magnetic stimulation (rTMS) and surgery-related deficits of language function. We pooled the bicentric language mapping data of 80 patients undergoing the resection of left-sided perisylvian brain lesions in our two university neurosurgical departments. We calculated error rates (ERs; ER = errors per stimulations) for both hemispheres and defined the hemispheric dominance ratio (HDR) as the quotient of the left- and right-sided ER (HDR >1= left dominant; HDR language function was evaluated and correlated with the preoperative HDR. Only three of 80 patients (4%) presented with permanent surgery-related aphasia and 24 patients (30%) with transient surgery-related aphasia. The mean HDR (± standard deviation) of patients with new aphasia after five days was significantly higher (1.68±1.07) than the HDR of patients with no new language deficit (1.37±1.08) (p=0.0482). With a predefined cut-off value of 0.5 for HDR, we achieved a sensitivity for predicting new aphasia of 100%. A higher preoperative HDR significantly correlates with an increased risk for transient aphasia. Moreover, the intensive preoperative workup in this study led to a considerably low rate of permanent aphasia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. [Recurrent left atrial myxoma].

    Science.gov (United States)

    Moreno Martínez, Francisco L; Lagomasino Hidalgo, Alvaro; Mirabal Rodríguez, Roger; López Bermúdez, Félix H; López Bernal, Omaida J

    2003-01-01

    Primary cardiac tumors are rare. Mixomas are the most common among them; 75% are located in the left atrium, 20% in the right atrium, and the rest in the ventricles. The seldom appear in atrio-ventricular valves. Recidivant mixoma are also rare, appearing in 1-5% of all patients that have undergone surgical treatment of a mixoma. In this paper we present our experience with a female patient, who 8 years after having been operated of a left atrial mixoma, began with symptoms of mild heart failure. Transthoracic echocardiography revealed recurrence of the tumor, and was therefore subjected to a second open-heart surgery from which she recovered without complications.

  8. Second harmonic generation from hemicyanine self-assembled monolayer on near-hemispherical gold nanoparticles

    Science.gov (United States)

    Tanaka, Daisuke; Yamaguchi, Tatsuya; Gupta, Gaurav; Okawa, Haruki; Hashimoto, Kazuhiko; Kajikawa, Kotaro

    2011-10-01

    Second-harmonic generation (SHG) was observed from hemicyanine-terminated alkanethiolate self-assembled monolayers (SAMs) formed on near-hemispherical gold nanoparticles (GNPs) prepared by annealing a vacuum-evaporated thin gold film deposited on a quartz glass substrate. The hemicyanine SAMs were formed on the near-hemispherical GNP by immersion of the substrate in an ethanol solution of hemicyanine-terminated alkanedisulfide. Polarized SHG measurements with the support of theoretical calculations revealed that the near-hemispherical GNP surfaces are fully covered with the hemicyanine SAMs. This result is in contrast to our previous study that showed that the hemicyanine SAM does not form fully over the spherical GNPs immobilized on a quartz glass substrate.

  9. Decreased GABA levels in the symptomatic hemisphere after Transient Ischaemic Attack

    DEFF Research Database (Denmark)

    Figlewski, Krystian; Andersen, Henning; Stærmose, Tobias

    Background and aims: In patients with stroke the GABA level is decreased in the lesioned hemisphere which may facilitate neurological recovery. In this study we aimed to determine the cortical levels of GABA and glutamate in patients after transient ischemic attack (TIA). Methods: Ten first......-time TIA patients with unilateral motor symptoms from upper limb and 10 healthy subjects underwent Magnetic Resonance Spectroscopy with SPECIAL technique. GABA and glutamate were measured in the hand area of the primary motor cortex (M1) in the symptomatic hemisphere. Results: Both GABA:Cr (p=0.......003) and Glutamate:Cr (p=0.0035) ratios were significantly lower in the symptomatic hemisphere of TIA patients than in healthy subjects. No difference was found in grey matter content within the scanned voxel (p=0.26) Conclusion: Even though the neurologigal function was reestablished, our study showed reduced GABA...

  10. Shortwave Array Spectroradiometer–Hemispheric (SASHe) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Connor J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    The Shortwave Array Spectroradiometer–Hemispheric (SASHe) provides measurements of direct solar, hemispheric diffuse, and total hemispheric shortwave irradiance over a continuous spectral range from approximately 300 nm to 1700 nm at a rate of about 30 seconds. The SASHe design connects an optical collector located outdoors to a pair of spectrometers and data collections systems located indoors within a climate-controlled building via an umbilical cable of fiber optic and electrical cables. The light collector uses a small Spectralon button as a hemispheric diffuser with a shadowband to distinguish signal from diffuse sky and direct sun.

  11. Subsonic aircraft soot. A tracer documenting barriers to inter-hemispheric mixing

    Energy Technology Data Exchange (ETDEWEB)

    Pueschel, R.F. [NASA Ames Research Center, Moffett Field, CA (United States)

    1997-12-31

    Meridional observations of soot aerosols and radioactive {sup 14}C, and models of the geographic distribution of nuclear bomb-released {sup 14}C and aircraft-emitted NO{sub x}, all show strong gradients between the hemispheres. Reason for it are decade-long inter-hemispheric mixing times which are much in excess of yearlong stratospheric residence times of tracers. Vertical mixing of soot aerosol is not corroborated by {sup 14}C observations. The reason could be radiometric forces that act on strongly absorbing soot. (author) 10 refs.

  12. Unifying Visual Space Across the Left and Right Hemifields.

    Science.gov (United States)

    Chen, Zhimin; Kosovicheva, Anna; Wolfe, Benjamin; Cavanagh, Patrick; Gorea, Andrei; Whitney, David

    2018-01-01

    Visual space is perceived as continuous and stable even though visual inputs from the left and right visual fields are initially processed separately within the two cortical hemispheres. In the research reported here, we examined whether the visual system utilizes a dynamic recalibration mechanism to integrate these representations and to maintain alignment across the visual fields. Subjects adapted to randomly oriented moving lines that straddled the vertical meridian; these lines were vertically offset between the left and right hemifields. Subsequent vernier alignment judgments revealed a negative aftereffect: An offset in the same direction as the adaptation was required to correct the perceived misalignment. This aftereffect was specific to adaptation to vertical, but not horizontal, misalignments and also occurred following adaptation to movie clips and patterns without coherent motion. Our results demonstrate that the visual system unifies the left and right halves of visual space by continuously recalibrating the alignment of elements across the visual fields.

  13. Plutonium in Southern Hemisphere ocean Waters

    DEFF Research Database (Denmark)

    Hirose, K.; Aoyama, M.; Gastaud, J.

    2013-01-01

    Plutonium in seawater collected by the BEAGLE2003 cruise was determined using ICP- SF-MS and alpha spectrometry after Fe co-precipitation and radiochemical purification. Levels and distributions of dissolved plutonium activity concentrations in Southern Hemisphere ocean waters are summarized here......, including historical data. Pu-239 concentrations in surface water----of the central South Pacific (32.5 °S) in 2003 were around 1 mBq/m3. The 239Pu concentrations in the Indian Ocean surface waters (20°S) were similar to that in the South Pacific, whereas the 239Pu concentrations in the South Atlantic...... surface waters (30°S) were markedly lower than those in the South Pacific and Indian Oceans. The 239Pu vertical profile pattern was similar to that in the North Pacific subtropical gyre, although 239Pu concentrations in the deep South Pacific were significantly lower than those in the North Pacific. One...

  14. Differences in lateral hemispheric asymmetries of cerebral blood flow measured by SPECT in dementia of Alzheimer type

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Nahoko (Niigata Univ. (Japan). School of Medicine)

    1993-12-01

    We studied 21 right-handed patients clinically diagnosed as dementia of Alzheimer type (8 men, 13 women; aged 53-85, mean 71.1 years). The average duration of symptoms was 2.7 years. Dementia ranged from mild to moderately severe. None had clinical or laboratory evidence of cerebro-vascular disease (Hachinski ischemic scores for all patients were 4 or below). All received the Wechsler Adult Intelligence Scale (WAIS), Mini-mental State Test (MMS) and Western Aphasia Battery (WAB, First Japanese edition, 1986). Regional cerebral blood flow was evaluated by single photon emission CT (SPECT) with [sup 123]I-N-isopropyl-p-iodoamphetamine ([sup 123]I-IMP), using the Matsuda's quantitative method. The subjects were divided into three groups on the basis of right-left hemispheric asymmetry of cerebral blood flow (leftleft, n=3; left=right, n=12). General scores (MMS, T-IQ) were not correlated with asymmetry of cerebral blood flow. Verbal IQ in patients with predominant hypoperfusion of left temporal and parietal lobe were significantly lower than in other groups, while performance IQ and WAB constructive scores were lower in those with right hemispheric hypoperfusion (p<0.05). We concluded that cerebral blood flow asymmetry detected by SPECT was related significantly to the deficit of language and constructive function in patients with dementia of Alzheimer type. (author).

  15. Hemispherical Resonator Gyro: an IRU for Cassini

    Science.gov (United States)

    Litty, Edward C.; Gresham, Lennor L.; Toole, Patrick A.; Beisecker, Debra A.

    1996-10-01

    The JPL Inertial Reference Unit (IRU) is the single most sophisticated assembly on the Cassini spacecraft. At the core of the IRU is the state-of-the-art, Litton Hemispherical Resonator Gyro (HRG). Launched in October 1997, Cassini's trajectory utilizes gravity assist maneuvers around Venus (two), Earth, and Jupiter over a seven year period, arriving at Saturn in June 2004. Its tour of the Saturnian system will last an additional four years. Although the Stellar Reference Unit (SRU) provides the ultimate reference for the spacecraft Attitude and Articulation Control System (AACS) and can be used to control the spacecraft under benign conditions, the Cassini IRU is essential during maneuvers and fault recovery operations, and for precision attitude stabilization during science data acquisition. Therefore, IRU reliability over the long Cassini mission is a critical concern. Following an extensive evaluation of possible alternatives, the Hemispherical Resonator Gyro (HRG) based IRU developed by Litton Guidance and Control Systems, was chosen for the Cassini mission. The HRG is an attitude rate sensor that has no physical wear-out mechanisms. Based on a principle first described by G. H. Bryan (1890) in his paper, 'On Beats in the Vibrations of a Revolving Cylinder or Bell', the HRG is created by vibrating a quartz resonator. This paper discusses the theory and modifications required to the design of the standard Space Inertial Reference Unit to adapt it to meet the requirements of the Cassini mission and the AACS interface. The Cassini mission is the first use of an IRU for a deep space planetary mission that does not use a spun-mass sensor.

  16. Left atrial appendage occlusion

    Directory of Open Access Journals (Sweden)

    Ahmad Mirdamadi

    2013-01-01

    Full Text Available Left atrial appendage (LAA occlusion is a treatment strategy to prevent blood clot formation in atrial appendage. Although, LAA occlusion usually was done by catheter-based techniques, especially percutaneous trans-luminal mitral commissurotomy (PTMC, it can be done during closed and open mitral valve commissurotomy (CMVC, OMVC and mitral valve replacement (MVR too. Nowadays, PTMC is performed as an optimal management of severe mitral stenosis (MS and many patients currently are treated by PTMC instead of previous surgical methods. One of the most important contraindications of PTMC is presence of clot in LAA. So, each patient who suffers of severe MS is evaluated by Trans-Esophageal Echocardiogram to rule out thrombus in LAA before PTMC. At open heart surgery, replacement of the mitral valve was performed for 49-year-old woman. Also, left atrial appendage occlusion was done during surgery. Immediately after surgery, echocardiography demonstrates an echo imitated the presence of a thrombus in left atrial appendage area, although there was not any evidence of thrombus in pre-pump TEE. We can conclude from this case report that when we suspect of thrombus of left atrial, we should obtain exact history of previous surgery of mitral valve to avoid misdiagnosis clotted LAA, instead of obliterated LAA. Consequently, it can prevent additional evaluations and treatments such as oral anticoagulation and exclusion or postponing surgeries including PTMC.

  17. Left ventricular diastolic performance of left ventricular hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikezono, Tohru; Ozaki, Masaharu; Yamagishi, Takashi; Shimizu, Tatsuro; Furutani, Yuji; Kusukawa, Reizo

    1987-02-01

    To study left ventricular diastolic performance in different forms of left ventricular hypertrophy, ECG gated cardiac blood pool scan was performed in 11 patients with hypertrophic nonobstructive cardiomyopathy (HCM) and in 19 patients with hypertension (HT), and left ventricular volume curve (LVVC) was analyzed and compared with those of 13 normal subjects (N). Ejection fraction (EF) and early filling volume ratio (the ratio of volume increment of 100 msec later than the zero point in the first derivative of LVVC to the end diastolic volume) (%EFV) were computed from LVVC. Peak ejection rate (PER) and peak filling rate (PFR) were obtained from the first derivative of LVVC. Peak ejection acceleration (PEA) and peak filling acceleration (PFA) were calculated from the second derivative of LVVC. EF, PER and PEA did not show any difference between these 3 groups. PFR was lower in HT (2.6 +- 0.5) compared with those in HCM (3.0 +- 0.5) (p < 0.05) and in N (3.4 +- 0.5) (p < 0.001), but the %EFV in HCM (4.9 +- 1.8) was lower than those in HT (6.9 +- 1.9) (p < 0.01) and in N (11.4 +- 1.4) (p < 0.001). Moreover, PFA in HCM (27.9 +- 7.2) was increased than those in HT (20.2 +- 5.4) (p < 0.01) with no differences between HCM and N (29.4 +- 8.1). Significant correlation was observed between PFR and PFA (Y = 0.06X + 1.4. r = 0.856. p < 0.001). These result indicate that, in HCM, reduced increase in early left ventricular volume is compensated by a greater filling acceleration. In contrast, there is no compensation by filling acceleration in HT.

  18. Gender and hemispheric differences in temporal lobe epilepsy: a VBM study.

    Science.gov (United States)

    Santana, Maria Teresa Castilho Garcia; Jackowski, Andrea Parolin; Britto, Fernanda Dos Santos; Sandim, Gabriel Barbosa; Caboclo, Luís Otávio Sales Ferreira; Centeno, Ricardo Silva; Carrete, Henrique; Yacubian, Elza Márcia Targas

    2014-04-01

    Gender differences are recognized in the functional and anatomical organization of the human brain. Differences between genders are probably expressed early in life, when differential rates of cerebral maturation occur. Sexual dimorphism has been described in temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS). Several voxel-based morphometry (VBM) studies have shown that TLE-MTS extends beyond mesial temporal structures, and that there are differences in the extent of anatomical damage between hemispheres, although none have approached gender differences. Our aim was to investigate gender differences and anatomical abnormalities in TLE-MTS. VBM5 was employed to analyze gender and hemispheric differences in 120 patients with TLE-MTS and 50 controls. VBM abnormalities were more widespread in left-TLE; while in women changes were mostly seen in temporal areas, frontal regions were more affected in men. Our study confirmed that gender and laterality are important factors determining the nature and severity of brain damage in TLE-MTS. Differential rates of maturation between gender and hemispheres may explain the distinct areas of anatomical damage in men and women. Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  19. Hypoplastic left heart syndrome

    Directory of Open Access Journals (Sweden)

    Thiagarajan Ravi

    2007-05-01

    Full Text Available Abstract Hypoplastic left heart syndrome(HLHS refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the left ventricular outflow tract. In addition, the syndrome includes underdevelopment of the left ventricle, aorta, and aortic arch, as well as mitral atresia or stenosis. HLHS has been reported to occur in approximately 0.016 to 0.036% of all live births. Newborn infants with the condition generally are born at full term and initially appear healthy. As the arterial duct closes, the systemic perfusion becomes decreased, resulting in hypoxemia, acidosis, and shock. Usually, no heart murmur, or a non-specific heart murmur, may be detected. The second heart sound is loud and single because of aortic atresia. Often the liver is enlarged secondary to congestive heart failure. The embryologic cause of the disease, as in the case of most congenital cardiac defects, is not fully known. The most useful diagnostic modality is the echocardiogram. The syndrome can be diagnosed by fetal echocardiography between 18 and 22 weeks of gestation. Differential diagnosis includes other left-sided obstructive lesions where the systemic circulation is dependent on ductal flow (critical aortic stenosis, coarctation of the aorta, interrupted aortic arch. Children with the syndrome require surgery as neonates, as they have duct-dependent systemic circulation. Currently, there are two major modalities, primary cardiac transplantation or a series of staged functionally univentricular palliations. The treatment chosen is dependent on the preference of the institution, its experience, and also preference. Although survival following initial surgical intervention has improved significantly over the last 20 years, significant mortality and morbidity are present for both surgical strategies. As a result pediatric cardiologists continue to be challenged by discussions with families regarding initial decision

  20. Can terrestrial laser scanners (TLSs) and hemispherical photographs predict tropical dry forest succession with liana abundance?

    Science.gov (United States)

    Sánchez-Azofeifa, Gerardo Arturo; Guzmán-Quesada, J. Antonio; Vega-Araya, Mauricio; Campos-Vargas, Carlos; Milena Durán, Sandra; D'Souza, Nikhil; Gianoli, Thomas; Portillo-Quintero, Carlos; Sharp, Iain

    2017-03-01

    Tropical dry forests (TDFs) are ecosystems with long drought periods, a mean temperature of 25 °C, a mean annual precipitation that ranges from 900 to 2000 mm, and that possess a high abundance of deciduous species (trees and lianas). What remains of the original extent of TDFs in the Americas remains highly fragmented and at different levels of ecological succession. It is estimated that one of the main fingerprints left by global environmental and climate change in tropical environments is an increase in liana coverage. Lianas are non-structural elements of the forest canopy that eventually kill their host trees. In this paper we evaluate the use of a terrestrial laser scanner (TLS) in combination with hemispherical photographs (HPs) to characterize changes in forest structure as a function of ecological succession and liana abundance. We deployed a TLS and HP system in 28 plots throughout secondary forests of different ages and with different levels of liana abundance. Using a canonical correlation analysis (CCA), we addressed how the VEGNET, a terrestrial laser scanner, and HPs could predict TDF structure. Likewise, using univariate analyses of correlations, we show how the liana abundance could affect the prediction of the forest structure. Our results suggest that TLSs and HPs can predict the differences in the forest structure at different successional stages but that these differences disappear as liana abundance increases. Therefore, in well known ecosystems such as the tropical dry forest of Costa Rica, these biases of prediction could be considered as structural effects of liana presence. This research contributes to the understanding of the potential effects of lianas in secondary dry forests and highlights the role of TLSs combined with HPs in monitoring structural changes in secondary TDFs.

  1. Hemispheric Specialization and Recognition Memory for Abstract and Realistic Pictures: A Comparison of Painters and Laymen

    Science.gov (United States)

    Vogt, S.; Magnussen, S.

    2005-01-01

    Recognition memory and hemispheric specialization were assessed for abstract colour/black and white pictures of sport situations in painters and visually naive subjects using a forced choice yes/no tachistoscopic procedure. Reaction times showed a significant three-way interaction of picture type, expertise, and visual field, indicating that…

  2. Right Hemispheric Dominance of Creative Insight: An Event-Related Potential Study

    Science.gov (United States)

    Shen, Wangbing; Liu, Chang; Zhang, Xiaojiang; Zhao, Xiaojun; Zhang, Jing; Yuan, Yuan; Chen, Yalin

    2013-01-01

    The purpose of this study was to investigate the hemispheric effect of creative insight. This study used high-density ERPs to record participants' brain activity while they performed an insight task. Results showed that both insight solutions and incomprehension solutions elicited a more negative ERP deflection (N320~550) than noninsight solutions…

  3. Imagine a mouse and an elephant: Hemispheric asymmetries of imagination.

    Science.gov (United States)

    Dural, Seda; Çetinkaya, Hakan; Güntürkün, Onur

    2017-05-01

    The present study aimed to explore the existence of an asymmetrical bias in the imagination of pairs of objects of unequal size. We assumed that such pairs are conceptualized with the smaller object being placed on the left, creating an ascending size order from left to right. Such a bias could derive from a cognitive strategy known from the mental number line. Sixty-four participants were instructed to imagine stimulus-pairs that were staggered from those showing very prominent intra-pair size differences (e.g., elephant vs. mouse) to very low size differences (e.g., orange vs. apple). The results showed that the tendency to imagine the bigger object on the right side increases with the size difference of the two stimuli. Such a visual field bias was also present in stimulus-pairs including numbers so that the participants imagined smaller and larger numbers on the left and the right side of the visual fields, respectively. Taken together, our findings could imply that the left-to-right orientation observed in our object imagining task may share the same cognitive mechanism as the mental number line.

  4. Design of a Quasi-Hemispherical UWB Antenna

    DEFF Research Database (Denmark)

    Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Franek, Ondrej

    2016-01-01

    This paper proposes a design of three-dimensional antenna for ultrawideband applications. The antenna has dimensions of 58 mm x 58 mm x 76.5 mm and is composed of two identical arms. Each arm consists of a hollow quasi-hemisphere and an inner for it tube. In the simulation, a 50 Ω coaxial cable...... is employed to feed the antenna in order to assess the change of the antenna performance due to the cable effect. The simulated results show that the antenna is capable of operating in the frequency band from 7 to 32.5 GHz with S11 below -10 dB, while maintaining an omnidirectional radiation pattern....... The simulated total efficiency is above 88 % over the entire impedance bandwidth which indicates a good antenna performance. The realized gain varies from 0.8 to 3.1 dBi with frequency....

  5. On the Relationship between Right- brain and Left- brain Dominance and Reading Comprehension Test Performance of Iranian EFL Learners

    Directory of Open Access Journals (Sweden)

    Hassan Soleimani

    2012-05-01

    Full Text Available A tremendous amount of works have been conducted by psycholinguistics to identify hemisphere processing during second/ foreign language learning, or in other words to investigate the role of the brain hemisphere dominance in language performance of learners. Most of these researches have focused on single words and word pairs (e.g., Anaki et al., 1998; Arzouan et. al., 2007; Faust & Mahal, 2007 or simple sentences (Rapp et al., 2007; Kacinik & Chiarello, 2007, and it has been discovered that there is an advantage of right hemisphere for metaphors and an
    advantage of left hemisphere for literal text. But the present research was designed to study Iranian EFL learners' performance in different reading tasks, so there could be differences between the consequences of the former research and the results of the present study due to the context. Here left-brain and right-brain dominance was investigated in 60 individuals (20 right-handed and 10 left-handed male, 20 right-handed and 10 left-handed female via the Edinburg Handedness Questionnaire (EHQ. The research results suggested that the right-handed learners who are supposed to be left-brain outperformed the left-handed ones; and regarding participant's gender, male learners outperformed female learners on reading comprehension test tasks.

  6. Enhanced early-latency electromagnetic activity in the left premotor cortex is associated with successful phonetic categorization.

    Science.gov (United States)

    Alho, Jussi; Sato, Marc; Sams, Mikko; Schwartz, Jean-Luc; Tiitinen, Hannu; Jääskeläinen, Iiro P

    2012-05-01

    Sensory-motor interactions between auditory and articulatory representations in the dorsal auditory processing stream are suggested to contribute to speech perception, especially when bottom-up information alone is insufficient for purely auditory perceptual mechanisms to succeed. Here, we hypothesized that the dorsal stream responds more vigorously to auditory syllables when one is engaged in a phonetic identification/repetition task subsequent to perception compared to passive listening, and that this effect is further augmented when the syllables are embedded in noise. To this end, we recorded magnetoencephalography while twenty subjects listened to speech syllables, with and without noise masking, in four conditions: passive perception; overt repetition; covert repetition; and overt imitation. Compared to passive listening, left-hemispheric N100m equivalent current dipole responses were amplified and shifted posteriorly when perception was followed by covert repetition task. Cortically constrained minimum-norm estimates showed amplified left supramarginal and angylar gyri responses in the covert repetition condition at ~100ms from stimulus onset. Longer-latency responses at ~200ms were amplified in the covert repetition condition in the left angular gyrus and in all three active conditions in the left premotor cortex, with further enhancements when the syllables were embedded in noise. Phonetic categorization accuracy and magnitude of voice pitch change between overt repetition and imitation conditions correlated with left premotor cortex responses at ~100 and ~200ms, respectively. Together, these results suggest that the dorsal stream involvement in speech perception is dependent on perceptual task demands and that phonetic categorization performance is influenced by the left premotor cortex. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Stratospheric influence on Northern Hemisphere winter climate variability

    Science.gov (United States)

    Ouzeau, Gaelle; Douville, Herve; Saint Martin, David

    2010-05-01

    Despite significant improvements in observing and data assimilation systems, long-range dynamical forecasting remains a difficult challenge for the climate modelling community. The skill of operational seasonal forecasting systems is particularly poor in the northern extratropics where seas surface temperature (SST) has a weaker influence than in the Tropics. It is therefore relevant to look for additional potential sources of long-range climate predictability in the stratosphere using ensembles of global atmospheric simulations. Besides a control experiment where the ARPEGE-Climat model is only driven by SST, parallel simulations have been performed in which an additional control on climate variability has been accounted for through the nudging of the northern extratropical stratosphere towards the ERA40 reanalysis. Though idealized, this original experiment design allows us to compare the relative contribution of the lower and upper boundary forcings on the simulated tropospheric variability. Results show that the stratospheric nudging improves the climatology and interannual variability of the mid-latitude troposphere, especially in winter in the Northern Hemisphere. Major impacts are found in particular on the simulation of the Arctic and North Atlantic oscillations (AO and NAO). Case studies were carried out for the 1976-1977 and 1988-1989 winters, corresponding to extreme phases of the AO. Results confirm the robustness of the positive impact of the nudging, especially for winter 1976-1977 corresponding to relatively weak SST anomalies in the tropical Pacific. A sensitivity study to the model resolution shows that a well-resolved stratosphere is not necessary for the nudging to be efficient. Besides seasonal mean results, analysis of the day-to-day variability in winter allowed us to better understand the stratospheric polar vortex influence on the tropospheric circulation in the Northern Hemisphere mid-latitudes.

  8. Advocacy in the Western Hemisphere Region: some FPA success stories.

    Science.gov (United States)

    Andrews, D J

    1996-01-01

    The International Planned Parenthood Federation's Vision 2000 Strategic Plan has emphasized advocacy and the training of family planning associations (FPAs) in the Western Hemisphere region. During the summer of 1995 training programs in advocacy leadership management were sponsored for six FPAs in the Bahamas, Suriname, Belize, Colombia, Honduras, and Brazil. At the Western Hemisphere Regional Council Meeting in September 1995 awards were presented to FPAs for media outstanding projects. These FPAs used outreach to the community to promote the goals of Vision 2000. The Bahamas FPA won the Rosa Cisneros Award for articles published in a magazine that is distributed in primary and secondary schools and deals with the activities, achievements, and opinions of students. Issues include: love, relationships, responsibility, and teen pregnancy. A weekly television talk show also addresses the issues facing youth including education, music, community work, sexuality, pregnancy, and the relationship between teenagers and adults. The Family Planning Association of Honduras was also nominated for the award for a radio show on the health of mothers and children, the problems of adolescents, and FP. The newspaper Tiempo received the award for feature articles on social issues and FP. In 1994 the Association distributed thousands of booklets on contraceptives as well as fliers on vasectomy, female sterilization, oral contraceptives, IUDs, condoms, responsible parenthood, high-risk pregnancy, vaginal cytology, and cervical cancer. Similar posters were placed in hospitals and health centers, in 1997 FP posts, and 400 commercial outlets. The Family Planning Association of Suriname also carried out an impressive advocacy program during the period of 1968-93 with the goals of establishing a balance between population growth and the available resources to achieve well-being with regard to education, health care, nutrition, and housing.

  9. Sleep Spindles in the Right Hemisphere Support Awareness of Regularities and Reflect Pre-Sleep Activations.

    Science.gov (United States)

    Yordanova, Juliana; Kolev, Vasil; Bruns, Eike; Kirov, Roumen; Verleger, Rolf

    2017-11-01

    The present study explored the sleep mechanisms which may support awareness of hidden regularities. Before sleep, 53 participants learned implicitly a lateralized variant of the serial response-time task in order to localize sensorimotor encoding either in the left or right hemisphere and induce implicit regularity representations. Electroencephalographic (EEG) activity was recorded at multiple electrodes during both task performance and sleep, searching for lateralized traces of the preceding activity during learning. Sleep EEG analysis focused on region-specific slow (9-12 Hz) and fast (13-16 Hz) sleep spindles during nonrapid eye movement sleep. Fast spindle activity at those motor regions that were activated during learning increased with the amount of postsleep awareness. Independently of side of learning, spindle activity at right frontal and fronto-central regions was involved: there, fast spindles increased with the transformation of sequence knowledge from implicit before sleep to explicit after sleep, and slow spindles correlated with individual abilities of gaining awareness. These local modulations of sleep spindles corresponded to regions with greater presleep activation in participants with postsleep explicit knowledge. Sleep spindle mechanisms are related to explicit awareness (1) by tracing the activation of motor cortical and right-hemisphere regions which had stronger involvement already during learning and (2) by recruitment of individually consolidated processing modules in the right hemisphere. The integration of different sleep spindle mechanisms with functional states during wake collectively supports the gain of awareness of previously experienced regularities, with a special role for the right hemisphere. © Sleep Research Society 2017. Published by Oxford University Press [on behalf of the Sleep Research Society].

  10. Hospital acquired pneumonia is linked to right hemispheric peri-insular stroke.

    Directory of Open Access Journals (Sweden)

    André Kemmling

    Full Text Available Hospital acquired pneumonia (HAP is a major complication of stroke. We sought to determine associations between infarction of specific brain regions and HAP.215 consecutive acute stroke patients with HAP (2003-2009 were carefully matched with 215 non-pneumonia controls by gender, then NIHSS, then age. Admission imaging and binary masks of infarction were registered to MNI-152 space. Regional atlas and voxel-based log-odds were calculated to assess the relationship between infarct location and the likelihood of HAP. An independently validated penalized conditional logistic regression model was used to identify HAP associated imaging regions.The HAP and control patients were well matched by gender (100%, age (95% within 5-years, NIHSS (98% within 1-point, infarct size, dysphagia, and six other clinical variables. Right hemispheric infarcts were more frequent in patients with HAP versus controls (43.3% vs. 34.0%, p = 0.054, whereas left hemispheric infarcts were more frequent in controls (56.7% vs. 44.7%, p = 0.012; there was no significant difference between groups in the rate of brainstem strokes (p = 1.0. Of the 10 most infarcted regions, only right insular cortex volume was different in HAP versus controls (20 vs. 12 ml, p = 0.02. In univariate analyses, the highest log-odds regions for pneumonia were right hemisphere, cerebellum, and brainstem. The best performing multivariate model selected 7 brain regions of infarction and 2 infarct volume-based variables independently associated with HAP.HAP is associated with right hemispheric peri-insular stroke. These associations may be related to autonomic modulation of immune mechanisms, supporting recent hypotheses of stroke mediated immune suppression.

  11. Neurophysiological Evidence That Musical Training Influences the Recruitment of Right Hemispheric Homologues for Speech Perception

    Directory of Open Access Journals (Sweden)

    McNeel Gordon Jantzen

    2014-03-01

    Full Text Available Musicians have a more accurate temporal and tonal representation of auditory stimuli than their non-musician counterparts (Kraus & Chandrasekaran, 2010; Parbery-Clark, Skoe, & Kraus, 2009; Zendel & Alain, 2008; Musacchia, Sams, Skoe, & Kraus, 2007. Musicians who are adept at the production and perception of music are also more sensitive to key acoustic features of speech such as voice onset timing and pitch. Together, these data suggest that musical training may enhance the processing of acoustic information for speech sounds. In the current study, we sought to provide neural evidence that musicians process speech and music in a similar way. We hypothesized that for musicians, right hemisphere areas traditionally associated with music are also engaged for the processing of speech sounds. In contrast we predicted that in non-musicians processing of speech sounds would be localized to traditional left hemisphere language areas. Speech stimuli differing in voice onset time was presented using a dichotic listening paradigm. Subjects either indicated aural location for a specified speech sound or identified a specific speech sound from a directed aural location. Musical training effects and organization of acoustic features were reflected by activity in source generators of the P50. This included greater activation of right middle temporal gyrus (MTG and superior temporal gyrus (STG in musicians. The findings demonstrate recruitment of right hemisphere in musicians for discriminating speech sounds and a putative broadening of their language network. Musicians appear to have an increased sensitivity to acoustic features and enhanced selective attention to temporal features of speech that is facilitated by musical training and supported, in part, by right hemisphere homologues of established speech processing regions of the brain.

  12. Rigidity, Chaos and Integration: Hemispheric Interaction and Individual Differences in Metaphor Comprehension

    Directory of Open Access Journals (Sweden)

    Miriam eFaust

    2014-07-01

    Full Text Available Neurotypical individuals cope flexibly with the full range of semantic relations expressed in human language, including metaphoric relations. This impressive semantic ability may be associated with distinct and flexible patterns of hemispheric interaction, including higher right hemisphere (RH involvement for processing novel metaphors. However, this ability may be impaired in specific clinical conditions, such as Asperger syndrome and schizophrenia. The impaired semantic processing is accompanied by different patterns of hemispheric interaction during semantic processing, showing either reduced (in Asperger or excessive (in schizophrenia RH involvement. This paper interprets these individual differences using the terms Rigidity, Chaos and Integration, which describe patterns of semantic memory network states that either lead to semantic well-being or are disruptive of it. We argue that these semantic network states lie on a rigidity-chaos semantic continuum. We define these terms via network science terminology and provide network, cognitive and neural evidence to support our claim. This continuum includes LH hyper-rigid semantic memory state on one end (e.g., in persons with Asperger syndrome, and RH chaotic and over-flexible semantic memory state on the other end (e.g., in persons with schizophrenia. In between these two extremes lie different states of semantic memory structure which are related to individual differences in semantic creativity. We suggest that efficient semantic processing is achieved by semantic integration, a balance between semantic rigidity and semantic chaos. Such integration is achieved via intra-hemispheric communication. However, impairments to this well-balanced and integrated pattern of hemispheric interaction, e.g., when one hemisphere dominates the other, may lead to either semantic rigidity or semantic chaos, moving away from semantic integration and thus impairing the processing of metaphoric language.

  13. Shape preferred orientation of iron grains compatible with Earth's uppermost inner core hemisphericity

    Science.gov (United States)

    Calvet, Marie; Margerin, Ludovic

    2018-01-01

    Constraining the possible patterns of iron fabrics in the Earth's Uppermost Inner Core (UIC) is key to unravel the mechanisms controlling its growth and dynamics. In the framework of crystalline micro-structures composed of ellipsoidal, aligned grains, we discuss possible textural models of UIC compatible with observations of P-wave attenuation and velocity dispersion. Using recent results from multiple scattering theory in textured heterogeneous materials, we compute the P-wave phase velocity and scattering attenuation as a function of grain volume, shape, and orientation wrt to the propagation direction of seismic P-waves. Assuming no variations of the grain volume between the Eastern and Western hemisphere, we show that two families of texture are compatible with the degree-one structure of the inner core as revealed by the positive correlation between seismic velocity and attenuation. (1) Strong flattening of grains parallel to the Inner Core Boundary in the Western hemisphere and weak anisometry in the Eastern hemisphere. (2) Strong radial elongation of grains in the Western hemisphere and again weak anisometry in the Eastern hemisphere. Both textures can quantitatively explain the seismic data in a limited range of grain volumes. Furthermore, the velocity and attenuation anisotropy locally observed under Africa demands that the grains be locally elongated in the direction of Earth's meridians. Our study demonstrates that the hemispherical seismic structure of UIC can be entirely explained by changes in the shape and orientation of grains, thereby offering an alternative to changes in grain volumes. In the future, our theoretical toolbox could be used to systematically test the compatibility of textures predicted by geodynamical models with seismic observations.

  14. [Effects of learning experiences on the shift of hemispheric functional asymmetry].

    Science.gov (United States)

    Yoshizaki, K

    1986-04-01

    Effects of learning experiences on the direction of shifts occurred in the functional asymmetry of the hemispheres were examined with unfamiliar stimuli. Hangul scripts were presented to 32 right handed university students who had no previous knowledge about Hangul. In the test session 1, the subjects were asked to discriminate the Hangul scripts tachistoscopically presented as fast and accurately as possible, and the left visual field advantage was obtained. The subjects were then assigned into following four groups with different conditions; to teach nothing, to teach the pronunciations of scripts, to teach the meanings of scripts, to teach both the pronunciations and the meanings of scripts. Then, the same discrimination task as that of the test session 1 was repeatedly given as the test session 2. No visual field differences was shown in the pronunciation teaching group, while the left visual field advantage was shown in other three groups. Possible mechanism as for the effects of learning experiences in relation to the hemispheric specialization were discussed.

  15. Radioactive fallout in the southern hemisphere from nuclear weapons tests

    International Nuclear Information System (INIS)

    Moroney, J.R.

    1979-11-01

    Fallout in the southern hemisphere, and its origins in the national programs of atmospheric nuclear weapons testing in both hemispheres, are reviewed. Of the 390 nuclear tests conducted in the atmosphere to date, 53 were carried out in the southern hemisphere and it is the second phase of these, between 1966 and 1974, that is seen to have been responsible for the main fallout of short-lived fission products in the southern hemisphere. In contrast to this, the programs of atmospheric nuclear testing in the northern hemisphere up to 1962 are shown to have been the main source of long-lived fission products in fallout in the southern hemisphere. The course followed by this contamination through the environment of the southern hemisphere is traced for the national programs of nuclear testing after 1962 taken separately (France, China) and for the earlier national programs taken together (U.S.S.R., U.S.A. and U.K.). The impact on populations in the southern hemisphere of fallout from atmospheric nuclear weapons tests to date is assessed

  16. The Hemispheric Sign Rule of Current Helicity during the Rising ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We compute the signs of two different current helicity parameters (i.e., best and ) for 87 active regions during the rise of cycle 23. The results indicate that 59% of the active regions in the northern hemisphere have negative best and 65% in the southern hemisphere have positive. This is consistent ...

  17. Disentangling the Relationship between Hemispheric Asymmetry and Cognitive Performance

    Science.gov (United States)

    Hirnstein, Marco; Leask, Stuart; Rose, Jonas; Hausmann, Markus

    2010-01-01

    It is widely believed that advantages of hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between hemispheric asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a…

  18. Radioactive fallout in the southern hemisphere from nuclear weapons tests

    International Nuclear Information System (INIS)

    Moroney, J.R.

    1979-01-01

    Fallout in the southern hemisphere, and its origins in the national programs of atmospheric nuclear weapons testing in both hemispheres, are reviewed. Of the 390 nuclear tests conducted in the atmosphere to date, 53 were carried out in the southern hemisphere and it is the second phase of these, between 1966 and 1974, that is seen to have been responsible for the main fallout of short-lived fission products in the southern hemisphere. In contrast to this, the programs of atmospheric nuclear testing in the northern hemisphere up to 1962 are shown to have been the main source of long-lived fission products in fallout in the southern hemisphere. The course followed by this contamination through the environment of the southern hemisphere is traced for the national programs of nuclear testing after 1962 taken separately (France, China) and for the earlier national programs taken together (U.S.S.R., U.S.A. and U.K.). The impact on populations in the southern hemisphere of fallout from atmospheric nuclear weapons tests to date is assessed. (author)

  19. A hierarchically assembled mesoporous ZnO hemisphere array and hollow microspheres for photocatalytic membrane water filtration.

    Science.gov (United States)

    Pan, Jia Hong; Zhang, Xiwang; Du, Alan J; Bai, Hongwei; Ng, Jiawei; Sun, Darren

    2012-05-28

    A mesoporous ZnO hemisphere array has been prepared via a topotactic transition of Zn(4)(OH)(6)CO(3)·H(2)O (ZCHH) by chemical bath deposition. Each hemisphere is comprised of a radially oriented nanoflake shell grown on the hemispherical interior. Reaction time-dependent SEM analysis shows that the morphological formation of ZCHH involves a deposition-growth-secondary growth-redeposition procedure. Upon calcination, ZCHH readily decomposes to nanocrystalline wurtzite-phase ZnO without significant change in morphology, and the release of CO(2) and H(2)O from ZCHH creates an additional mesoporous structure in both hemispherical interior and nanoflake shell. A similar process but without using a substrate has been developed for synthesis of mesoporous ZnO hollow microspheres in powder form. Both the elaborated superstructured photocatalysts consisting of mesoporous nanoflakes have been demonstrated to exhibit excellent performances in the photocatalytic membrane filtration.

  20. Inkjet printed superparamagnetic polymer composite hemispheres with programmed magnetic anisotropy

    Science.gov (United States)

    Ergeneman, Olgaç; Peters, Christian; Gullo, Maurizio R.; Jacot-Descombes, Loïc; Gervasoni, Simone; Özkale, Berna; Fatio, Philipe; Cadarso, Victor J.; Mastrangeli, Massimo; Pané, Salvador; Brugger, Jürgen; Hierold, Christofer; Nelson, Bradley J.

    2014-08-01

    We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this work superparamagnetic magnetite nanoparticles are dispersed in SU-8 to form magnetic hemispheres. Magnetically anisotropic hemispheres as well as standard SPMPC hemispheres are fabricated. Magnetic anisotropy is programmed by applying a magnetic field during curing. The distribution of nanoparticles inside the polymer matrix and magnetic characteristics of the SPMPC are investigated. Magnetic manipulation of hemispheres is demonstrated at liquid-liquid interfaces. Different assembly strategies to form lines or geometric shapes from hemispheres as well as their independent dynamic control are demonstrated. Finally, a two-interface assembly strategy is demonstrated to assemble hemispheres into complete spheres for advanced self-assembly tasks.We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this

  1. Left Ventricular Assist Devices

    Directory of Open Access Journals (Sweden)

    Khuansiri Narajeenron

    2017-04-01

    Full Text Available Audience: The audience for this classic team-based learning (cTBL session is emergency medicine residents, faculty, and students; although this topic is applicable to internal medicine and family medicine residents. Introduction: A left ventricular assist device (LVAD is a mechanical circulatory support device that can be placed in critically-ill patients who have poor left ventricular function. After LVAD implantation, patients have improved quality of life.1 The number of LVAD patients worldwide continues to rise. Left-ventricular assist device patients may present to the emergency department (ED with severe, life-threatening conditions. It is essential that emergency physicians have a good understanding of LVADs and their complications. Objectives: Upon completion of this cTBL module, the learner will be able to: 1 Properly assess LVAD patients’ circulatory status; 2 appropriately resuscitate LVAD patients; 3 identify common LVAD complications; 4 evaluate and appropriately manage patients with LVAD malfunctions. Method: The method for this didactic session is cTBL.

  2. Hemispherical Resonator Gyroscope Accuracy Analysis Under Temperature Influence

    Directory of Open Access Journals (Sweden)

    Boran LI

    2014-06-01

    Full Text Available Frequency splitting of hemispherical resonator gyroscope will change as system operating temperature changes. This phenomenon leads to navigation accuracy of hemispherical resonator gyroscope reduces. By researching on hemispherical resonator gyroscope dynamical model and its frequency characteristic, the frequency splitting formula and the precession angle formula of gyroscope vibrating mode based on hemispherical resonator gyroscope dynamic equation parameters are derived. By comparison, gyroscope precession angle deviation caused by frequency splitting can be obtained. Based on analysis of temperature variation against gyroscope resonator, the design of hemispherical resonator gyroscope feedback controller under temperature variation conditions is researched and the maximum theoretical fluctuation of gyroscope dynamical is determined by using a numerical analysis example.

  3. Seismic hazard map of the western hemisphere

    Science.gov (United States)

    Shedlock, K.M.; Tanner, J.G.

    1999-01-01

    Vulnerability to natural disasters increases with urbanization and development of associated support systems (reservoirs, power plants, etc.). Catastrophic earthquakes account for 60% of worldwide casualties associated with natural disasters. Economic damage from earthquakes is increasing, even in technologically advanced countries with some level of seismic zonation, as shown by the 1989 Loma Prieta, CA ($6 billion), 1994 Northridge, CA ($ 25 billion), and 1995 Kobe, Japan (> $ 100 billion) earthquakes. The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures, due to an insufficient knowledge of existing seismic hazard. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes), emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of the Americas is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful global seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA) with a 10% chance of exceedance in 50 years for the western hemisphere. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions specify the

  4. Seismic hazard map of the western hemisphere

    Directory of Open Access Journals (Sweden)

    J. G. Tanner

    1999-06-01

    Full Text Available Vulnerability to natural disasters increases with urbanization and development of associated support systems (reservoirs, power plants, etc.. Catastrophic earthquakes account for 60% of worldwide casualties associated with natural disasters. Economic damage from earthquakes is increasing, even in technologically advanced countries with some level of seismic zonation, as shown by the 1989 Loma Prieta, CA ($ 6 billion, 1994 Northridge, CA ($ 25 billion, and 1995 Kobe, Japan (> $ 100 billion earthquakes. The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures, due to an insufficient knowledge of existing seismic hazard. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes depends on reliable estimates of seismic hazard. National, state, and local governments, decision makers, engineers, planners, emergency response organizations, builders, universities, and the general public require seismic hazard estimates for land use planning, improved building design and construction (including adoption of building construction codes, emergency response preparedness plans, economic forecasts, housing and employment decisions, and many more types of risk mitigation. The seismic hazard map of the Americas is the concatenation of various national and regional maps, involving a suite of approaches. The combined maps and documentation provide a useful global seismic hazard framework and serve as a resource for any national or regional agency for further detailed studies applicable to their needs. This seismic hazard map depicts Peak Ground Acceleration (PGA with a 10% chance of exceedance in 50 years for the western hemisphere. PGA, a short-period ground motion parameter that is proportional to force, is the most commonly mapped ground motion parameter because current building codes that include seismic provisions

  5. She is not a beauty even when she smiles: Possible evolutionary basis for a relationship between facial attractiveness and hemispheric specialization

    OpenAIRE

    Zaidel, Dahlia. W.; Chen, Audrey; German, Craig

    1995-01-01

    The asymmetrical status of facial beauty has rarely been investigated. We studied positive facial characteristics, attractiveness and smiling, through the use of left-left and right-right composites of unfamiliar faces of women and men with natural expressions. Results showed that women's right-right composites were judged significantly more attractive than left-left composites while there was no left-right difference in men's composites (Experiment 1). On the other hand, left-left composites...

  6. Hemispheric language asymmetry in first episode psychosis and schizotypy: the role of cannabis consumption and cognitive disorganization.

    Science.gov (United States)

    Herzig, Daniela A; Sullivan, Sarah; Lewis, Glyn; Corcoran, Rhiannon; Drake, Richard; Evans, Jonathan; Nutt, David; Mohr, Christine

    2015-03-01

    Cannabis use has been related to an elevated psychosis risk and attenuated cognitive functioning. Cannabis-related cognitive impairments are also observed in populations along the psychosis dimension. We here investigated whether a potential behavioral marker of the psychosis dimension (attenuated functional hemispheric asymmetry) is even further attenuated in individuals using cannabis (CU) vs those not using cannabis (nCU). We tested 29 patients with first-episode psychosis (FEP; 11 CU) and 90 healthy controls (38 CU) on lateralized lexical decisions assessing left-hemisphere language dominance. In patients, psychotic symptoms were assessed by Positive & Negative Symptom Scale (PANSS). In controls, self-reported schizotypy was assessed (The Oxford-Liverpool Inventory of Feelings and Experiences: O-LIFE). Results indicated that nCU FEP patients had a relative reduced hemispheric asymmetry, as did controls with increasing cognitive disorganization (CogDis) scores, in particular when belonging to the group of nCU controls. Positive, disorganized and negative PANSS scores in patients and negative and positive schizotypy in controls were unrelated to hemispheric asymmetry. These findings suggest that cannabis use potentially balances rather than exacerbates uncommon hemispheric laterality patterns. Moreover, in healthy populations, the potential stabilization of typical hemispheric asymmetry in CU might be most relevant to individuals with elevated CogDis. We discuss the potential beneficial and harmful effects of cannabis use along the psychosis dimension together with propositions for future studies that should account for the mediating role of additional substances (eg nicotine), cannabis composition (eg cannabidiol content), and individual differences (eg physical health, or absence of significant polysubstance use). © The Author 2014. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions

  7. Hemispheric Language Asymmetry in First Episode Psychosis and Schizotypy: The Role of Cannabis Consumption and Cognitive Disorganization

    Science.gov (United States)

    Herzig, Daniela A.; Sullivan, Sarah; Lewis, Glyn; Corcoran, Rhiannon; Drake, Richard; Evans, Jonathan; Nutt, David; Mohr, Christine

    2015-01-01

    Cannabis use has been related to an elevated psychosis risk and attenuated cognitive functioning. Cannabis-related cognitive impairments are also observed in populations along the psychosis dimension. We here investigated whether a potential behavioral marker of the psychosis dimension (attenuated functional hemispheric asymmetry) is even further attenuated in individuals using cannabis (CU) vs those not using cannabis (nCU). We tested 29 patients with first-episode psychosis (FEP; 11 CU) and 90 healthy controls (38 CU) on lateralized lexical decisions assessing left-hemisphere language dominance. In patients, psychotic symptoms were assessed by Positive & Negative Symptom Scale (PANSS). In controls, self-reported schizotypy was assessed (The Oxford-Liverpool Inventory of Feelings and Experiences: O-LIFE). Results indicated that nCU FEP patients had a relative reduced hemispheric asymmetry, as did controls with increasing cognitive disorganization (CogDis) scores, in particular when belonging to the group of nCU controls. Positive, disorganized and negative PANSS scores in patients and negative and positive schizotypy in controls were unrelated to hemispheric asymmetry. These findings suggest that cannabis use potentially balances rather than exacerbates uncommon hemispheric laterality patterns. Moreover, in healthy populations, the potential stabilization of typical hemispheric asymmetry in CU might be most relevant to individuals with elevated CogDis. We discuss the potential beneficial and harmful effects of cannabis use along the psychosis dimension together with propositions for future studies that should account for the mediating role of additional substances (eg nicotine), cannabis composition (eg cannabidiol content), and individual differences (eg physical health, or absence of significant polysubstance use). PMID:25543118

  8. How to engage the right brain hemisphere in aphasics without even singing: evidence for two paths of speech recovery.

    Science.gov (United States)

    Stahl, Benjamin; Henseler, Ilona; Turner, Robert; Geyer, Stefan; Kotz, Sonja A

    2013-01-01

    There is an ongoing debate as to whether singing helps left-hemispheric stroke patients recover from non-fluent aphasia through stimulation of the right hemisphere. According to recent work, it may not be singing itself that aids speech production in non-fluent aphasic patients, but rhythm and lyric type. However, the long-term effects of melody and rhythm on speech recovery are largely unknown. In the current experiment, we tested 15 patients with chronic non-fluent aphasia who underwent either singing therapy, rhythmic therapy, or standard speech therapy. The experiment controlled for phonatory quality, vocal frequency variability, pitch accuracy, syllable duration, phonetic complexity and other influences, such as the acoustic setting and learning effects induced by the testing itself. The results provide the first evidence that singing and rhythmic speech may be similarly effective in the treatment of non-fluent aphasia. This finding may challenge the view that singing causes a transfer of language function from the left to the right hemisphere. Instead, both singing and rhythmic therapy patients made good progress in the production of common, formulaic phrases-known to be supported by right corticostriatal brain areas. This progress occurred at an early stage of both therapies and was stable over time. Conversely, patients receiving standard therapy made less progress in the production of formulaic phrases. They did, however, improve their production of non-formulaic speech, in contrast to singing and rhythmic therapy patients, who did not. In light of these results, it may be worth considering the combined use of standard therapy and the training of formulaic phrases, whether sung or rhythmically spoken. Standard therapy may engage, in particular, left perilesional brain regions, while training of formulaic phrases may open new ways of tapping into right-hemisphere language resources-even without singing.

  9. How to engage the right brain hemisphere in aphasics without even singing: evidence for two paths of speech recovery

    Directory of Open Access Journals (Sweden)

    Benjamin eStahl

    2013-02-01

    Full Text Available There is an ongoing debate as to whether singing helps left-hemispheric stroke patients recover from non-fluent aphasia through stimulation of the right hemisphere. According to recent work, it may not be singing itself that aids speech production in non-fluent aphasic patients, but rhythm and lyric type. However, the long-term effects of melody and rhythm on speech recovery are largely unknown. In the current experiment, we tested 15 patients with chronic non-fluent aphasia who underwent either singing therapy, rhythmic therapy, or standard speech therapy. The experiment controlled for phonatory quality, vocal frequency variability, pitch accuracy, syllable duration, phonetic complexity and other influences, such as the acoustic setting and learning effects induced by the testing itself. The results provide the first evidence that singing and rhythmic speech may be similarly effective in the treatment of non-fluent aphasia. This finding may challenge the view that singing causes a transfer of language function from the left to the right hemisphere. Instead, both singing and rhythmic therapy patients made good progress in the production of common, formulaic phrases—known to be supported by right corticostriatal brain areas. This progress occurred at an early stage of both therapies and was stable over time. Conversely, patients receiving standard therapy made less progress in the production of formulaic phrases. They did, however, improve their production of non-formulaic speech, in contrast to singing and rhythmic therapy patients, who did not. In light of these results, it may be worth considering the combined use of standard therapy and the training of formulaic phrases, whether sung or rhythmically spoken. Standard therapy may engage, in particular, left perilesional brain regions, while training of formulaic phrases may open new ways of tapping into right-hemisphere language resources—even without singing.

  10. Reduced fractional anisotropy of corpus callosum modulates inter-hemispheric resting state functional connectivity in migraine patients without aura.

    Science.gov (United States)

    Yuan, Kai; Qin, Wei; Liu, Peng; Zhao, Ling; Yu, Dahua; Zhao, Limei; Dong, Minghao; Liu, Jixin; Yang, Xuejuan; von Deneen, Karen M; Liang, Fanrong; Tian, Jie

    2012-01-01

    Diffusion tensor imaging (DTI) study revealed reduced fractional anisotropy (FA) values in the corpus callosum (CC) in migraine patients without aura. Abnormalities in white matter integrity, particularly in the CC, may affect inter-hemispheric resting state functional connectivity (RSFC). Unfortunately, relatively little is known about the alterations in functional interactions between the cerebral hemispheres during resting state in migraine patients without aura, and even less about how the inter-hemispheric RSFC are affected by the abnormalities of the CC. Twenty-one migraine patients without aura and 21 healthy controls participated in this study, age-, sex-, and education-matched. Tract-based spatial statistics (TBSS) was employed to investigate the white matter alterations of the CC. Meanwhile, voxel-mirrored homotopic connectivity (VMHC) was used to compare the inter-hemispheric RSFC differences between the patients and controls. TBSS analysis revealed reduced FA values in the genu and the splenium of CC in patient group. VMHC analysis showed decreased inter-hemispheric RSFC of anterior cingulate cortex (ACC) in migraine patients without aura relative to that of the controls. Furthermore, in migraine patients without aura, the reduced FA values of the genu of CC correlated with the decreased inter-hemispheric RSFC of the ACC. Our findings demonstrated that the migraine patients without aura showed reduced FA values of the genu of CC and decreased inter-hemispheric RSFC of the ACC. The correlation between the above structural and functional changes suggested that the reduced fractional anisotropy (FA) of CC modulates inter-hemispheric VMHC in migraine patients without aura. Our results demonstrated that the VMHC alterations of ACC can reflect the FA changes of the genu of CC in migraine patients without aura.

  11. The left inferior frontal gyrus: A neural crossroads between abstract and concrete knowledge.

    Science.gov (United States)

    Della Rosa, Pasquale Anthony; Catricalà, Eleonora; Canini, Matteo; Vigliocco, Gabriella; Cappa, Stefano F

    2018-04-12

    Evidence from both neuropsychology and neuroimaging suggests that different types of information are necessary for representing and processing concrete and abstract word meanings. Both abstract and concrete concepts, however, conjointly rely on perceptual, verbal and contextual knowledge, with abstract concepts characterized by low values of imageability (IMG) (low sensory-motor grounding) and low context availability (CA) (more difficult to contextualize). Imaging studies supporting differences between abstract and concrete concepts show a greater recruitment of the left inferior frontal gyrus (LIFG) for abstract concepts, which has been attributed either to the representation of abstract-specific semantic knowledge or to the request for more executive control than in the case of concrete concepts. We conducted an fMRI study on 27 participants, using a lexical decision task involving both abstract and concrete words, whose IMG and CA values were explicitly modelled in separate parametric analyses. The LIFG was significantly more activated for abstract than for concrete words, and a conjunction analysis showed a common activation for words with low IMG or low CA only in the LIFG, in the same area reported for abstract words. A regional template map of brain activations was then traced for words with low IMG or low CA, and BOLD regional time-series were extracted and correlated with the specific LIFG neural activity elicited for abstract words. The regions associated to low IMG, which were functionally correlated with LIFG, were mainly in the left hemisphere, while those associated with low CA were in the right hemisphere. Finally, in order to reveal which LIFG-related network increased its connectivity with decreases of IMG or CA, we conducted generalized psychophysiological interaction analyses. The connectivity strength values extracted from each region connected with the LIFG were correlated with specific LIFG neural activity for abstract words, and a regression

  12. Spatial Deficit in Familial Left-Handed Children.

    Science.gov (United States)

    And Others; Eme, Robert

    1978-01-01

    The study evaluated the hypothesis that familial left-handed children, who presumably have bilateral representation of language ability, should show an impairment in spatial abiblity on 44 children (22 right handed, 11 familial left handed, and 11 nonfamilial left handed) whose average age was 8 years old. (Author/PHR)

  13. Positive trends in Southern Hemisphere carbonyl sulfide

    Science.gov (United States)

    Kremser, Stefanie; Jones, Nicholas B.; Palm, Mathias; Lejeune, Bernard; Wang, Yuting; Smale, Dan; Deutscher, Nicholas M.

    2015-11-01

    Transport of carbonyl sulfide (OCS) from the troposphere to the stratosphere contributes sulfur to the stratospheric aerosol layer, which reflects incoming short-wave solar radiation, cooling the climate system. Previous analyses of OCS observations have shown no significant trend, suggesting that OCS is unlikely to be a major contributor to the reported increases in stratospheric aerosol loading and indicating a balanced OCS budget. Here we present analyses of ground-based Fourier transform spectrometer measurements of OCS at three Southern Hemisphere sites spanning 34.45°S to 77.80°S. At all three sites statistically significant positive trends are seen from 2001 to 2014 with an observed overall trend in total column OCS at Wollongong of 0.73 ± 0.03%/yr, at Lauder of 0.43 ± 0.02%/yr, and at Arrival Heights of 0.45 ± 0.05%/yr. These observed trends in OCS imply that the OCS budget is not balanced and could contribute to constraints on current estimates of sources and sinks.

  14. Remote Control Southern Hemisphere SSA Observatory

    Science.gov (United States)

    Ritchie, I.; Pearson, M.; Sang, J.

    2013-09-01

    EOS Space Systems (EOSSS) is a research and development company which has developed custom observatories, camera and telescope systems for space surveillance since 1996, as well as creating several evolutions of systems control software for control of observatories and laser tracking systems. Our primary reserach observatory is the Space Reserach Centre (SRC) at Mount Stromlo Asutralia. The current SRC control systems are designed such that remote control can be offered for real time data collection, noise filtering and flexible session management. Several imaging fields of view are available simultaneously for tracking orbiting objects, with real time imaging to Mag 18. Orbiting objects can have the centroids post processed into orbital determination/ orbital projection (OD/OP) elements. With or without laser tracking of orbiting objects, they can be tracked in terminator conditions and their OD/OP data created, then enhanced by proprietary methods involving ballistic coefficient estimation and OD convergence pinning, using a priori radar elements. Sensors in development include a thermal imager for satellite thermal signature detection. Extending laser tracking range by use of adaptive optics beam control is also in development now. This Southern Hemisphere observatory is in a unique position to facilitate the study of space debris, either stand-alone or as part of a network such as Falcon. Current national and international contracts will enhance the remote control capabilities further, creating a resource ready to go for a wide variety of SSA missions.

  15. Climate change induced by Southern Hemisphere desertification

    Science.gov (United States)

    Wang, Ye; Yan, Xiaodong

    2017-12-01

    Some 10-20% of global dry-lands are already degraded, and the ongoing desertification threatens the world's poorest populations. Studies on desertification effects are essential for humans to adapt to the environmental challenges posed by desertification. Given the importance of the much larger southern ocean to the global climate and the Southern Hemisphere (SH) climate changes in phase with those in the north, the biogeophysical effects of the SH desertification on climate are assessed using an Earth system model of intermediate complexity, MPM-2. This analysis focuses on differences in climate among the averages of simulations with desert expansion in different latitude bands by year 2000. The localized desertification causes significant global changes in temperature and precipitation as well as surface albedo. On the global scale, cooling dominates the SH desertification effects. However, the biogeophysical effects are most significant in regions with desertification, and the cooling is also prominent in northern mid-latitudes. Desert expansion in 15°-30°S reveals statistically most significant cooling and increased precipitation over the forcing regions during spring. The global and regional scale responses from desertification imply the climate teleconnection and address the importance of the effects from the SH which are contingent on the location of the forcing. Our study indicates that biogeophysical mechanisms of land cover changes in the SH need to be accounted for in the assessment of land management options especially for latitude band over 15°-30°S.

  16. Leftward spatial bias in children's drawing placement: hemispheric activation versus directional hypotheses.

    Science.gov (United States)

    Picard, Delphine; Zarhbouch, Benaissa

    2014-01-01

    A leftward spatial bias in drawing placement was demonstrated by Heller (1991) using the draw-a-person test with right-handed American children. No such bias was observed in left-handed children who are assumed to be less lateralised than their right-handed peers. According to Heller the leftward spatial bias is primarily a reflection of the right hemisphere specialisation for spatial processing. However, an alternative explanation in terms of directional trends may be put forward. In the present study we first confirm Heller's findings of a handedness effect on drawing placement using the draw-a-tree task with a large sample of right- and left-handed French children aged 5-15 years (Exp. 1). We then provide evidence that a similar leftward bias occurs in right-handed Moroccan children aged 7-11 years with opposite script directionality and opposite preferred drawing movement directions (i.e., right-to-left directional trends) to the those of right-handed French children (Exp. 2). Taken together these findings suggest that directionality trends arising from learned cultural habits and motor preferences play little role in determining spatial bias in the centring of a single object drawn on a page. Rather there may be a cerebral origin for drawing single objects slightly on the left side of the graphic space.

  17. Reading without the left ventral occipito-temporal cortex

    Science.gov (United States)

    Seghier, Mohamed L.; Neufeld, Nicholas H.; Zeidman, Peter; Leff, Alex P.; Mechelli, Andrea; Nagendran, Arjuna; Riddoch, Jane M.; Humphreys, Glyn W.; Price, Cathy J.

    2012-01-01

    The left ventral occipito-temporal cortex (LvOT) is thought to be essential for the rapid parallel letter processing that is required for skilled reading. Here we investigate whether rapid written word identification in skilled readers can be supported by neural pathways that do not involve LvOT. Hypotheses were derived from a stroke patient who acquired dyslexia following extensive LvOT damage. The patient followed a reading trajectory typical of that associated with pure alexia, re-gaining the ability to read aloud many words with declining performance as the length of words increased. Using functional MRI and dynamic causal modelling (DCM), we found that, when short (three to five letter) familiar words were read successfully, visual inputs to the patient’s occipital cortex were connected to left motor and premotor regions via activity in a central part of the left superior temporal sulcus (STS). The patient analysis therefore implied a left hemisphere “reading-without-LvOT” pathway that involved STS. We then investigated whether the same reading-without-LvOT pathway could be identified in 29 skilled readers and whether there was inter-subject variability in the degree to which skilled reading engaged LvOT. We found that functional connectivity in the reading-without-LvOT pathway was strongest in individuals who had the weakest functional connectivity in the LvOT pathway. This observation validates the findings of our patient’s case study. Our findings highlight the contribution of a left hemisphere reading pathway that is activated during the rapid identification of short familiar written words, particularly when LvOT is not involved. Preservation and use of this pathway may explain how patients are still able to read short words accurately when LvOT has been damaged. PMID:23017598

  18. Visualisation of the left superior intercostal vein in MR

    International Nuclear Information System (INIS)

    Medrea, M.; Meydam, K.; Schmitt, W.

    1987-01-01

    A retrospective study of 56 MRT chest examinations showed the left intercostal vein in its horizontal trajectory in 3 patients with left mediastinal masses compressing the superior vena cava. In 2 patients the posterior trajectory of the horizontal segment was clearly visualised. In the third case the anterior part, namely the insertion of the left superior intercostal vein into the left brachiocephalic trunk, was demonstrated. (orig.) [de

  19. A positive association between active lifestyle and hemispheric lateralization for motor control and learning in older adults.

    Science.gov (United States)

    Wang, Jinsung; D'Amato, Arthur; Bambrough, Jennifer; Swartz, Ann M; Miller, Nora E

    2016-11-01

    Physical activity (PA) is well known to have general health benefits for older adults, but it is unclear whether it can also positively affect brain function involved in motor control and learning. We have previously shown that interlimb transfer of visuomotor adaptation occurs asymmetrically in young adults, while that occurs symmetrically in older adults, which suggests that the lateralized function of each hemisphere during motor tasks is diminished with aging. Here, we investigated the association between the level of PA and hemispheric motor lateralization by comparing the pattern of interlimb transfer following visuomotor adaptation between physically active and inactive older adults. Subjects were divided into two groups based on their PA level (active, inactive). They were further divided into two groups, such that a half of the subjects in each group adapted to a 30° rotation during targeted reaching movements with the left arm first, then with the right arm; and the other half with the right arm first, then with the left arm. Results indicated asymmetrical transfer (from left to right only) in the active subjects, whereas symmetrical transfer (from left to right, and vice versa) was observed in the inactive subjects. These findings suggest that older adults who maintain active lifestyle have a central nervous system that is more intact in terms of its lateralized motor function as compared with those who are inactive. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  1. Left Ventricular Pseudoaneurysm Perceived as a Left Lung Mass

    Directory of Open Access Journals (Sweden)

    Ugur Gocen

    2013-02-01

    Full Text Available Left ventricular pseudo-aneurysm is a rare complication of aneurysmectomy. We present a case of surgically-treated left ventricular pseudo-aneurysm which was diagnosed three years after coronary artery bypass grafting and left ventricular aneurysmectomy. The presenting symptoms, diagnostic evaluation and surgical repair are described. [Cukurova Med J 2013; 38(1.000: 123-125

  2. [Vectorcardiographic manifestations of left intraventricular conduction disorders].

    Science.gov (United States)

    de Micheli, A; Medrano, G A

    1979-01-01

    Both, the vectorcardiographic changes produced by the various degrees of left bundle branch block and these observed with the different types of left distal block, are described. When a "wave jumping" phenomenon exists, the vectorcardiographic changes are more characteristic in the horizontal plane than in the frontal plane and can be interpreted satisfactorily in basis of the ventricular activation sequence. The normal counterclockwise rotation of the horizontal vectorcardiogram persists in the presence of left bundle branch block of slight and moderate degrees, since the electromotive forces of the free left ventricular wall are still predominant. In the majority of intermediate degree blocks, the middle portion of the RH loop develops with a clockwise rotation and general aspect with a clockwise rotation and the general aspect of the ventricular loop resembles an eight figure. This is due to the electromotive forces originated by the delayed depolarization of the left septal mass that starts to predominate. With advanced degrees of block, the largest portion of the RH loop shows a clockwise rotation, as well as marked notchings and slurrings. The initial anterior portion of the horizontal vectorcardiogram does not disappear, but is situated to the left of the anterior-posterior axis with a counterclockwise rotation (first right septal vector). Otherwise, the direct electrical sign of left distal block emphasized: evidence of delayed activation in a limited zone of the homolateral ventricle. This local delay gives rise to an asynchronism of the activation phenomenon between the upper and lower regions of the ventricle. The diagnosis of left bifascicular block is based essentially on the evidence of unequal delay of the activation sequence in the basal regions and in the inferior ones of the homolateral ventricle and also on the frequent persistence of the first left septal vector.

  3. Language plasticity after hemispherotomy of the dominant hemisphere in 3 patients: Implication of non-linguistic networks.

    Science.gov (United States)

    Bulteau, Christine; Jambaqué, Isabelle; Chiron, Catherine; Rodrigo, Sebastian; Dorfmüller, Georg; Dulac, Olivier; Hertz-Pannier, Lucie; Noulhiane, Marion

    2017-04-01

    The neural networks involved in language recovery following hemispherotomy of the dominant hemisphere after language acquisition in children remain poorly known. Twelve hemispherotomized children (mean age at surgery: 11.3years) with comparable post-operative neuropsychological patterns underwent multi-task language functional MRI. Three of them had recovered from an initial postoperative aphasia i.e., hemispherotomy was performed on the language-dominant hemisphere. Our main results revealed (1) perisylvian activations in all patients after either left or right hemispherotomy; (2) no differences in activations between groups regarding the side of hemispherotomy; (3) additional activations in pre-frontal (3/3) and hippocampal/parahippocampal and occipito-parietal (2/3) areas, when comparing language activation in each of the three subjects with hemispherotomy of the language-dominant hemisphere to the group of 9 non-dominant hemispherotomized patients. These neural networks support the stronger engagement of learning and memory during language recovery in a hemisphere that was not initially actively subserving language. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Right hemisphere role in cognitive reserve.

    Science.gov (United States)

    Robertson, Ian H

    2014-06-01

    High levels of education, occupational complexity, and/or premorbid intelligence are associated with lower levels of cognitive impairment than would be expected from a given brain pathology. This has been observed across a range of conditions including Alzheimer's disease (Roe et al., 2010), stroke (Ojala-Oksala et al., 2012), traumatic brain injury (Kesler et al., 2003), and penetrating brain injury (Grafman, 1986). This cluster of factors, which seemingly protect the brain from expressing symptoms of damage, has been termed "cognitive reserve" (Stern, 2012). The current review considers one possible neural network, which may contribute to cognitive reserve. Based on the evidence that the neurotransmitter, noradrenaline mediates cognitive reserve's protective effects (Robertson, 2013) this review identifies the neurocognitive correlates of noradrenergic (NA) activity. These involve a set of inter-related cognitive processes (arousal, sustained attention, response to novelty, and awareness) with a strongly right hemisphere, fronto-parietal localization, along with working memory, which is also strongly modulated by NA. It is proposed that this set of processes is one plausible candidate for partially mediating the protective effects of cognitive reserve. In addition to its biological effects on brain structure and function, NA function may also facilitate networks for arousal, novelty, attention, awareness, and working memory, which collectively provide for a set of additional, cognitive, mechanisms that help the brain adapt to age-related changes and disease. It is hypothesized that to the extent that the lateral surface of the right prefrontal lobe and/or the right inferior parietal lobe maintain structural (white and gray matter) and functional integrity and connectivity, cognitive reserve should benefit and behavioral expression of pathologic damage should thus be mitigated. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Aging affects hemispheric asymmetry in the neural representation of speech sounds.

    Science.gov (United States)

    Bellis, T J; Nicol, T; Kraus, N

    2000-01-15

    Hemispheric asymmetries in the processing of elemental speech sounds appear to be critical for normal speech perception. This study investigated the effects of age on hemispheric asymmetry observed in the neurophysiological responses to speech stimuli in three groups of normal hearing, right-handed subjects: children (ages, 8-11 years), young adults (ages, 20-25 years), and older adults (ages > 55 years). Peak-to-peak response amplitudes of the auditory cortical P1-N1 complex obtained over right and left temporal lobes were examined to determine the degree of left/right asymmetry in the neurophysiological responses elicited by synthetic speech syllables in each of the three subject groups. In addition, mismatch negativity (MMN) responses, which are elicited by acoustic change, were obtained. Whereas children and young adults demonstrated larger P1-N1-evoked response amplitudes over the left temporal lobe than over the right, responses from elderly subjects were symmetrical. In contrast, MMN responses, which reflect an echoic memory process, were symmetrical in all subject groups. The differences observed in the neurophysiological responses were accompanied by a finding of significantly poorer ability to discriminate speech syllables involving rapid spectrotemporal changes in the older adult group. This study demonstrates a biological, age-related change in the neural representation of basic speech sounds and suggests one possible underlying mechanism for the speech perception difficulties exhibited by aging adults. Furthermore, results of this study support previous findings suggesting a dissociation between neural mechanisms underlying those processes that reflect the basic representation of sound structure and those that represent auditory echoic memory and stimulus change.

  6. [Unilateral apraxia of eyelid closure in ischemic stroke: role of the right hemisphere in the emotional gesture communication].

    Science.gov (United States)

    Pérez-Martínez, D A; Puente-Muñoz, A I; Doménech, J; Baztán, J J; Berbel-Garcia, A; Porta-Etessam, J

    Apraxia of eyelid closure (AEC) is an infrequent disorder that is characterised by the inability to close the eyelids on command, although spontaneous blinking and reflex shutting of the eyes is preserved. Very few cases of unilateral AEC have been reported and no long-term follow-ups have been carried out. We report the case of a patient with unilateral AEC that was followed up over a 3-year period and also discuss the role played by the right hemisphere in this disorder. CASE REPORT" We examined the case of a 67-year-old right-handed male who was admitted because of a parietotemporal infarction with extension into the subcortex. A few days after the stroke the patient reported the inability to close his left eye on command, although he was still able to blink spontaneously and the blink and visual threat reflexes were preserved. This deficiency was associated to a dense hemiparesis on the left side and notable aprosodia affecting language. At 3 years' follow-up the AEC had not improved significantly. There are data to suggest that the right hemisphere is related to emotional perception and expressiveness, as well as the regulation of language prosody. Likewise, symbolic anthropology stresses the importance of winking as a gesture involved in non-verbal communication. These data suggest that AEC may be a consequence of a dysfunction of the role played by the right hemisphere in emotional expressiveness through gestures. The association with language aprosodia could support this hypothesis.

  7. White-matter microstructure and language lateralization in left-handers: a whole-brain MRI analysis.

    Science.gov (United States)

    Perlaki, Gabor; Horvath, Reka; Orsi, Gergely; Aradi, Mihaly; Auer, Tibor; Varga, Eszter; Kantor, Gyongyi; Altbäcker, Anna; John, Flora; Doczi, Tamas; Komoly, Samuel; Kovacs, Norbert; Schwarcz, Attila; Janszky, Jozsef

    2013-08-01

    Most people are left-hemisphere dominant for language. However the neuroanatomy of language lateralization is not fully understood. By combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we studied whether language lateralization is associated with cerebral white-matter (WM) microstructure. Sixteen healthy, left-handed women aged 20-25 were included in the study. Left-handers were targeted in order to increase the chances of involving subjects with atypical language lateralization. Language lateralization was determined by fMRI using a verbal fluency paradigm. Tract-based spatial statistics analysis of DTI data was applied to test for WM microstructural correlates of language lateralization across the whole brain. Fractional anisotropy and mean diffusivity were used as indicators of WM microstructural organization. Right-hemispheric language dominance was associated with reduced microstructural integrity of the left superior longitudinal fasciculus and left-sided parietal lobe WM. In left-handed women, reduced integrity of the left-sided language related tracts may be closely linked to the development of right hemispheric language dominance. Our results may offer new insights into language lateralization and structure-function relationships in human language system. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Right cerebral hemisphere and central auditory processing in children with developmental dyslexia

    Directory of Open Access Journals (Sweden)

    Paulina C. Murphy-Ruiz

    2013-11-01

    Full Text Available Objective We hypothesized that if the right hemisphere auditory processing abilities can be altered in children with developmental dyslexia (DD, we can detect dysfunction using specific tests. Method We performed an analytical comparative cross-sectional study. We studied 20 right-handed children with DD and 20 healthy right-handed control subjects (CS. Children in both groups were age, gender, and school-grade matched. Focusing on the right hemisphere’s contribution, we utilized tests to measure alterations in central auditory processing (CAP, such as determination of frequency patterns; sound duration; music pitch recognition; and identification of environmental sounds. We compared results among the two groups. Results Children with DD showed lower performance than CS in all CAP subtests, including those that preferentially engaged the cerebral right hemisphere. Conclusion Our data suggests a significant contribution of the right hemisphere in alterations of CAP in children with DD. Thus, right hemisphere CAP must be considered for examination and rehabilitation of children with DD.

  9. Effects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression.

    Science.gov (United States)

    Ishima, Rieko

    2015-09-01

    Abundant solvent nuclear spins, such as water protons in aqueous solution, cause radiation damping in NMR experiments. It is important to know how the effect of radiation damping appears in high-resolution protein NMR because macromolecular studies always require very high magnetic field strengths with a highly sensitive NMR probe that can easily cause radiation damping. Here, we show the behavior of water magnetization after a pulsed-field gradient (PFG) using nutation experiments at 900 MHz with a cryogenic probe: when water magnetization is located in the upper hemisphere (having +Z component, parallel to the external magnetic field), dephasing of the magnetization by a PFG effectively suppresses residual water magnetization in the transverse plane. In contrast, when magnetization is located in the lower hemisphere (having -Z component), the small residual transverse component remaining after a PFG is still sufficient to induce radiation damping. Based on this observation, we designed 1 H- 15 N HSQC experiments in which water magnetization is maintained in the upper hemisphere, but not necessarily along Z, and compared them with the conventional experiments, in which water magnetization is inverted during the t 1 period. The result demonstrates moderate gain of signal-to-noise ratio, 0-28%. Designing the experiments such that water magnetization is maintained in the upper hemisphere allows shorter pulses to be used compared to the complete water flip-back and, thereby, is useful as a building block of protein NMR pulse programs in solution.

  10. Hemispheric asymmetry of emotion words in a non-native mind: a divided visual field study.

    Science.gov (United States)

    Jończyk, Rafał

    2015-05-01

    This study investigates hemispheric specialization for emotional words among proficient non-native speakers of English by means of the divided visual field paradigm. The motivation behind the study is to extend the monolingual hemifield research to the non-native context and see how emotion words are processed in a non-native mind. Sixty eight females participated in the study, all highly proficient in English. The stimuli comprised 12 positive nouns, 12 negative nouns, 12 non-emotional nouns and 36 pseudo-words. To examine the lateralization of emotion, stimuli were presented unilaterally in a random fashion for 180 ms in a go/no-go lexical decision task. The perceptual data showed a right hemispheric advantage for processing speed of negative words and a complementary role of the two hemispheres in the recognition accuracy of experimental stimuli. The data indicate that processing of emotion words in non-native language may require greater interhemispheric communication, but at the same time demonstrates a specific role of the right hemisphere in the processing of negative relative to positive valence. The results of the study are discussed in light of the methodological inconsistencies in the hemifield research as well as the non-native context in which the study was conducted.

  11. [A clinical study of the number processing system: decimal size effects on reading numbers in patients with left parieto-occipital gliomas].

    Science.gov (United States)

    Gasparini, F M; Cohen, L; Lopes, M; Denvil, D; Capelle, L; Duffau, H; Van Effenterre, R

    2005-04-01

    An increasing number of studies are focusing on the anatomo-functional organisation of number processing and some cognitive models have been recently developed. Nevertheless, relationships between areas implicated in number processing, and language areas and circuits remain unclear. Recently, Dehaene and Cohen, in their "triple-code model of number processing", (Dehaene and Cohen, 1995) distinguished two alternative number representation and processing systems: one depending on verbal processes, the other representing a quantity manipulation. According to this model, the retrieval of "arithmetical facts" (AF), learned by rote at school and memorised in a verbal form (such as the multiplication table or simple addition problems) can be considered as a verbal automatism; conversely, subtraction problems, which require mental manipulation of the quantities, represent an abstract, semantic elaboration: "Actual Calculation" (AC). The anatomical correlate of the retrieval of AF (depending on automatic verbal associations) seems to correspond to the left-hemispheric perisylvian areas, while impairment of the actual calculation (AC) depends on the intraparietal region, particularly in the left dominant hemisphere. The present study describes the neuropsychological assessment of three patients, tested after surgery for left parieto-occipital tumors. Two of them were affected by an anaplasic glioma, the third by a low-grade glioma. The cognitive evaluation included: words of Rey, numeral (directed and reversed) span, reading of "simple" numbers (from 1 to 10) and of "complex" numbers (many decimals), writing (dictation) and reading a standard text, finger denomination and right-left distinction. All patients showed language disturbances, dysgraphia and severe dyslexia. In reading numbers, we identified two types of errors: lexical and syntactic. "Lexical errors" consisted in a wrong choice among words in the number's lexicon. For instance, all patients made errors in reading

  12. Theories of inter-hemispheric interactions in aphasia: the role of tDCS in rehabilitation of post-stroke aphasia

    Directory of Open Access Journals (Sweden)

    Roy H Hamilton

    2014-04-01

    Full Text Available Mounting data from behavioral and neuroimaging studies have shown that the process of recovery from aphasia is largely driven by the reorganization of brain networks related to language. Evidence implicates a variety of potential mechanisms in this reorganization, some of which involve substantive changes in brain functional activity within and between cerebral hemispheres. These changes include intrahemispheric recruitment of perilesional left-hemisphere regions and transcallosal interhemispheric interactions between lesioned left-hemisphere language areas and homologous regions in the right hemisphere. With respect to the role of the right hemisphere, it is debated whether interhemispheric interactions are beneficial or deleterious to recovering language networks. Recent years have also seen the emergence of noninvasive brain stimulation techniques such as transcranial magnetic stimulation (TMS and transcranial direct current stimulation (tDCS as potential novel treatments for post-stroke aphasia. Because these techniques are predicated on either focal excitation or inhibition of brain areas, characterization of the functional roles of the left and right hemispheres and transcallosal interactions in aphasia recovery is of central importance to the development and refinement of stimulation-based therapies. However, most treatment studies involving noninvasive brain stimulation in aphasia have tacitly accepted the interhemispheric inhibition model, in which right hemisphere activity interferes with language recovery that is mediated by left hemisphere perisylvian regions. Based on this account, many studies in aphasia involving TMS and tDCS have adopted one of two approaches consistent with the model: left hemisphere excitation or right hemisphere inhibition. In this presentation, we will review both clinical and cognitive neuroscience evidence that elucidates different hemispheric mechanisms that influence recovery from aphasia after stroke

  13. Superior Temporal Gyrus Volume Abnormalities and Thought Disorder in Left-Handed Schizophrenic Men

    Science.gov (United States)

    Holinger, Dorothy P.; Shenton, Martha E.; Wible, Cynthia G.; Donnino, Robert; Kikinis, Ron; Jolesz, Ferenc A.; McCarley, Robert W.

    2010-01-01

    Objective Studies of schizophrenia have not clearly defined handedness as a differentiating variable. Moreover, the relationship between thought disorder and anatomical anomalies has not been studied extensively in left-handed schizophrenic men. The twofold purpose of this study was to investigate gray matter volumes in the superior temporal gyrus of the temporal lobe (left and right hemispheres) in left-handed schizophrenic men and left-handed comparison men, in order to determine whether thought disorder in the left-handed schizophrenic men correlated with tissue volume abnormalities. Method Left-handed male patients (N=8) with DSM-III-R diagnoses of schizophrenia were compared with left-handed comparison men (N=10) matched for age, socioeconomic status, and IQ. Magnetic resonance imaging (MRI) with a 1.5-T magnet was used to obtain scans, which consisted of contiguous 1.5-mm slices of the whole brain. MRI analyses (as previously defined by the authors) included the anterior, posterior, and total superior temporal gyrus in both the left and right hemispheres. Results There were three significant findings regarding the left-handed schizophrenic men: 1) bilaterally smaller gray matter volumes in the posterior superior temporal gyrus (16% smaller on the right, 15% smaller on the left); 2) a smaller volume on the right side of the total superior temporal gyrus; and 3) a positive correlation between thought disorder and tissue volume in the right anterior superior temporal gyrus. Conclusions These results suggest that expression of brain pathology differs between left-handed and right-handed schizophrenic men and that the pathology is related to cognitive disturbance. PMID:10553736

  14. Somatic Activation of AKT3 Causes Hemispheric Developmental Brain Malformations

    Science.gov (United States)

    Poduri, Annapurna; Evrony, Gilad D.; Cai, Xuyu; Elhosary, Princess Christina; Beroukhim, Rameen; Lehtinen, Maria K.; Hills, L. Benjamin; Heinzen, Erin L.; Hill, Anthony; Hill, R. Sean; Barry, Brenda J.; Bourgeois, Blaise F.D.; Riviello, James J.; Barkovich, A. James; Black, Peter M.; Ligon, Keith L.; Walsh, Christopher A.

    2012-01-01

    Summary Hemimegalencephaly (HMG) is a developmental brain disorder characterized by an enlarged, malformed cerebral hemisphere, typically causing epilepsy that requires surgical resection. We studied resected HMG tissue to test whether the condition might reflect somatic mutations affecting genes critical to brain development. We found that 2/8 HMG samples showed trisomy of chromosome 1q, encompassing many genes, including AKT3, which is known to regulate brain size. A third case showed a known activating mutation in AKT3 (c.49G→A, creating p.E17K) that was not present in the patient’s blood cells. Remarkably, the E17K mutation in AKT3 is exactly paralogous to E17K mutations in AKT1 and AKT2 recently discovered in somatic overgrowth syndromes. We show that AKT3 is the most abundant AKT paralogue in brain during neurogenesis and that phosphorylated AKT is abundant in cortical progenitor cells. Our data suggest that somatic mutations limited to brain could represent an important cause of complex neurogenetic disease. PMID:22500628

  15. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Science.gov (United States)

    Balzarotti, Stefania; Colombo, Barbara

    2016-01-01

    The dorsolateral prefrontal cortex (DLPFC) is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant) pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  16. Effects of Unilateral Transcranial Direct Current Stimulation of Left Prefrontal Cortex on Processing and Memory of Emotional Visual Stimuli.

    Directory of Open Access Journals (Sweden)

    Stefania Balzarotti

    Full Text Available The dorsolateral prefrontal cortex (DLPFC is generally thought to be involved in affect and emotional processing; however, the specific contribution of each hemisphere continues to be debated. In the present study, we employed unilateral tDCS to test the unique contribution of left DLPFC in the encoding and retrieval of emotional stimuli in healthy subjects. Forty-two right handed undergraduate students received either anodal, cathodal or sham stimulation of left DLPFC while viewing neutral, pleasant, and unpleasant pictures. After completing a filler task, participants were asked to remember as many pictures as possible. Results showed that participants were able to remember a larger amount of emotional (both pleasant and unpleasant pictures than of neutral ones, regardless of the type of tDCS condition. Participants who received anodal stimulation recalled a significantly higher number of pleasant images than participants in the sham and cathodal conditions, while no differences emerged in the recall of neutral and unpleasant pictures. We conclude that our results provide some support to the role of left prefrontal cortex in the encoding and retrieval of pleasant stimuli.

  17. You talkin' to me? Communicative talker gaze activates left-lateralized superior temporal cortex during perception of degraded speech.

    Science.gov (United States)

    McGettigan, Carolyn; Jasmin, Kyle; Eisner, Frank; Agnew, Zarinah K; Josephs, Oliver J; Calder, Andrew J; Jessop, Rosemary; Lawson, Rebecca P; Spielmann, Mona; Scott, Sophie K

    2017-06-01

    Neuroimaging studies of speech perception have consistently indicated a left-hemisphere dominance in the temporal lobes' responses to intelligible auditory speech signals (McGettigan and Scott, 2012). However, there are important communicative cues that cannot be extracted from auditory signals alone, including the direction of the talker's gaze. Previous work has implicated the superior temporal cortices in processing gaze direction, with evidence for predominantly right-lateralized responses (Carlin & Calder, 2013). The aim of the current study was to investigate whether the lateralization of responses to talker gaze differs in an auditory communicative context. Participants in a functional MRI experiment watched and listened to videos of spoken sentences in which the auditory intelligibility and talker gaze direction were manipulated factorially. We observed a left-dominant temporal lobe sensitivity to the talker's gaze direction, in which the left anterior superior temporal sulcus/gyrus and temporal pole showed an enhanced response to direct gaze - further investigation revealed that this pattern of lateralization was modulated by auditory intelligibility. Our results suggest flexibility in the distribution of neural responses to social cues in the face within the context of a challenging speech perception task. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Functional MRI assessment of hemispheric language dominance with using a lexical decision task

    International Nuclear Information System (INIS)

    Ryoo, Jae Wook; Choi, Dae Seob; Cho, Jae Min; Park, Eui Dong; You, Jin Jong; Na, Dong Gyu; Kim, Sam Soo; Cha, Sang Hoon

    2005-01-01

    We wanted to compare the fMRIs (functional magnetic resonance images) obtained during a lexical decision task and also during a word generation task, and we wanted to evaluate the usefulness of using a lexical decision task for the visualization of the brain language area and for the determination of language dominance. Sixteen patients (9 women and 7 men) who had had undergone the Wada test were included in our study. All the patients were left dominant for language, as tested for on the Wada test. The functional maps of the brain language area were obtained in all the subjects during the performance of a lexical decision task and also during the performance of a word generation task. The MR examinations were performed with a 1.5 T scanner and with using the EPI BOLD technique. We used the SPM program for the postprocessing of the images. The threshold for significance was set at ρ <0.001 or ρ <0.01. A lateralization index was calculated from the number of activated pixels in each hemispheric region (the whole hemisphere, the frontal lobe and the temporoparietal lobe), and the hemispheric language dominance was assessed by the lateralization index; the results were then compared with those results of the Wada test. The differences for the lateralization of the language area were analyzed with regard to the stimulation tasks and the regions used for the calculation of the lateralization indices. The number of activated pixels during the lexical decision task was significantly smaller than that of the word generation task. The language dominance based on the activated signals in each hemisphere, was consistent with the results of the Wada test for the word generation tasks in all the subjects. On the lexical decision task, the language dominance, as determined by the activated signals in each hemisphere and the temporoparietal lobe, correlated for 94% of the patients. The mean values of the lateralization index for the lexical decision task were higher than those

  19. Why Dora Left

    DEFF Research Database (Denmark)

    Gammelgård, Judy

    2017-01-01

    The question of why Dora left her treatment before it was brought to a satisfactory end and the equally important question of why Freud chose to publish this problematic and fragmentary story have both been dealt with at great length by Freud’s successors. Dora has been read by analysts, literary...... critics, and not least by feminists. The aim of this paper is to point out the position Freud took toward his patient. Dora stands out as the one case among Freud’s 5 great case stories that has a female protagonist, and reading the case it becomes clear that Freud stumbled because of an unresolved...... problem toward femininity, both Dora’s and his own. In Dora, it is argued, Freud took a new stance toward the object of his investigation, speaking from the position of the master. Freud presents himself as the one who knows, in great contrast to the position he takes when unraveling the dream. Here he...

  20. A Novel Hemispherical and Dynamic Camera for EVAs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project is to develop a novel Hemispherical and Dynamic Camera(HDC) with ultra-wide field of view and low geometric distortion. The novel technology we...

  1. Globalization, energy and sustainable development in the hemisphere

    International Nuclear Information System (INIS)

    Villegas Rodriguez, Luis Carlos

    1999-01-01

    Presently paper, it is emphasized in the politics in the environmental and energetic field that has taken place in the hemisphere like consequence of the setting of the action plan agreed in the summit of the America in 1994

  2. ISLSCP II Northern Hemisphere Monthly Snow Cover Extent

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This ISLSCP data set is derived from the National Snow and Ice Data Center (NSIDC) Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent...

  3. Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multisensor Analyzed Sea Ice Extent Northern Hemisphere (MASIE-NH) products provide measurements of daily sea ice extent and sea ice edge boundary for the...

  4. Prediction Center (CPC) Tropical/ Northern Hemisphere Teleconnection Pattern Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the Tropical/ Northern Hemisphere teleconnection pattern. The data spans the period 1950 to present. The index is derived from a rotated...

  5. ISLSCP II Northern Hemisphere Monthly Snow Cover Extent

    Data.gov (United States)

    National Aeronautics and Space Administration — This ISLSCP data set is derived from the National Snow and Ice Data Center (NSIDC) Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent product which...

  6. Modelling the Main Ionospheric Trough Across the Northern Hemisphere

    National Research Council Canada - National Science Library

    Mitchell, Cathryn

    2004-01-01

    This report results from a contract tasking University of Bath as follows: The contractor will investigate disturbances in the Northern Hemisphere ionosphere using a Multi-instrument data analysis (MIDAS) imaging algorithm...

  7. Search for Trends and Periodicities in Inter-hemispheric Sea Surface Temperature Difference

    Science.gov (United States)

    Rajesh, R.; Tiwari, R. K.

    2018-02-01

    Understanding the role of coupled solar and internal ocean dynamics on hemispheric climate variability is critical to climate modelling. We have analysed here 165 year long annual northern hemispheric (NH) and southern hemispheric (SH) sea surface temperature (SST) data employing spectral and statistical techniques to identify the imprints of solar and ocean-atmospheric processes, if any. We reconstructed the eigen modes of NH-SST and SH-SST to reveal non-linear oscillations superimposed on the monotonic trend. Our analysis reveals that the first eigen mode of NH-SST and SH-SST representing long-term trend of SST variability accounts for 15-23% variance. Interestingly, these components are matching with first eigen mode (99% variance) of the total solar irradiance (TSI) suggesting possible impact of solar activity on long-term SST variation. Furthermore, spectral analysis of SSA reconstructed signal revealed statistically significant periodicities of 63 ± 5, 22 ± 2, 10 ± 1, 7.6, 6.3, 5.2, 4.7, and 4.2 years in both NH-SST and SH-SST data. The major harmonics centred at 63 ± 5, 22 ± 2, and 10 ± 1 years are similar to solar periodicities and hence may represent solar forcing, while the components peaking at around 7.6, 6.3, 5.2, 4.7, and 4.2 years apparently falls in the frequency bands of El-Nino-Southern Oscillations linked to the oceanic internal processes. Our analyses also suggest evidence for the amplitude modulation of 9-11 and 21-22 year solar cycles, respectively, by 104 and 163 years in northern and southern hemispheric SST data. The absence of the above periodic oscillations in CO2 fails to suggest its role on observed inter-hemispheric SST difference. The cross-plot analysis also revealed strong influence of solar activity on linear trend of NH- and SH-SST in addition to small contribution from CO2. Our study concludes that (1) the long-term trends in northern and southern hemispheric SST variability show considerable synchronicity with cyclic

  8. Polar cap index as a proxy for hemispheric Joule heating

    DEFF Research Database (Denmark)

    Chun, F.K.; Knipp, D.J.; McHarg, M.G.

    1999-01-01

    input into the polar cap, we propose to use PC as a proxy for the hemispheric Joule heat production rate (JH). In this study, JH is estimated from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. We fit hourly PC values to hourly averages of JH. Using a data base approximately...... is as equally accurate. Thus the single station PC index appears to provide a quick estimate of, and is an appropriate proxy for, the hemispheric Joule heating rate....

  9. Precipitation phase partitioning variability across the Northern Hemisphere

    Science.gov (United States)

    Jennings, K. S.; Winchell, T. S.; Livneh, B.; Molotch, N. P.

    2017-12-01

    Precipitation phase drives myriad hydrologic, climatic, and biogeochemical processes. Despite its importance, many of the land surface models used to simulate such processes and their sensitivity to climate warming rely on simple, spatially uniform air temperature thresholds to partition rainfall and snowfall. Our analysis of a 29-year dataset with 18.7 million observations of precipitation phase from 12,143 stations across the Northern Hemisphere land surface showed marked spatial variability in the near-surface air temperature at which precipitation is equally likely to fall as rain and snow, the 50% rain-snow threshold. This value averaged 1.0°C and ranged from -0.4°C to 2.4°C for 95% of the stations analyzed. High-elevation continental areas such as the Rocky Mountains of the western U.S. and the Tibetan Plateau of central Asia generally exhibited the warmest thresholds, in some cases exceeding 3.0°C. Conversely, the coldest thresholds were observed on the Pacific Coast of North America, the southeast U.S., and parts of Eurasia, with values dropping below -0.5°C. Analysis of the meteorological conditions during storm events showed relative humidity exerted the strongest control on phase partitioning, with surface pressure playing a secondary role. Lower relative humidity and surface pressure were both associated with warmer 50% rain-snow thresholds. Additionally, we trained a binary logistic regression model on the observations to classify rain and snow events and found including relative humidity as a predictor variable significantly increased model performance between 0.6°C and 3.8°C when phase partitioning is most uncertain. We then used the optimized model and a spatially continuous reanalysis product to map the 50% rain-snow threshold across the Northern Hemisphere. The map reproduced patterns in the observed thresholds with a mean bias of 0.5°C relative to the station data. The above results suggest land surface models could be improved by

  10. Standardizing the protocol for hemispherical photographs: accuracy assessment of binarization algorithms.

    Science.gov (United States)

    Glatthorn, Jonas; Beckschäfer, Philip

    2014-01-01

    Hemispherical photography is a well-established method to optically assess ecological parameters related to plant canopies; e.g. ground-level light regimes and the distribution of foliage within the crown space. Interpreting hemispherical photographs involves classifying pixels as either sky or vegetation. A wide range of automatic thresholding or binarization algorithms exists to classify the photographs. The variety in methodology hampers ability to compare results across studies. To identify an optimal threshold selection method, this study assessed the accuracy of seven binarization methods implemented in software currently available for the processing of hemispherical photographs. Therefore, binarizations obtained by the algorithms were compared to reference data generated through a manual binarization of a stratified random selection of pixels. This approach was adopted from the accuracy assessment of map classifications known from remote sensing studies. Percentage correct (Pc) and kappa-statistics (K) were calculated. The accuracy of the algorithms was assessed for photographs taken with automatic exposure settings (auto-exposure) and photographs taken with settings which avoid overexposure (histogram-exposure). In addition, gap fraction values derived from hemispherical photographs were compared with estimates derived from the manually classified reference pixels. All tested algorithms were shown to be sensitive to overexposure. Three of the algorithms showed an accuracy which was high enough to be recommended for the processing of histogram-exposed hemispherical photographs: "Minimum" (Pc 98.8%; K 0.952), "Edge Detection" (Pc 98.1%; K 0.950), and "Minimum Histogram" (Pc 98.1%; K 0.947). The Minimum algorithm overestimated gap fraction least of all (11%). The overestimation by the algorithms Edge Detection (63%) and Minimum Histogram (67%) were considerably larger. For the remaining four evaluated algorithms (IsoData, Maximum Entropy, MinError, and Otsu

  11. Midlatitude weather systems on Mars: Is there a hemispheric asymmetry?

    Science.gov (United States)

    Barnes, J. R.

    1992-01-01

    The Viking Lander meteorology observations confirmed that midlatitude weather systems are present in the Northern Hemisphere of Mars during the autumn, winter, and early spring. These systems have properties consistent with a development through baroclinic instability of the wintertime zonal-mean circulation. It is known that the weather systems must be of importance for the zonal-mean circulation by virtue of their heat and momentum transports. Observations show that they are associated with dust raising, and they must be involved in the transport of dust; the weather systems almost certainly must act to produce significant water transports as well. Recent simulations with the ARC Mars General Circulation Model (GCM) show that the heat transports by the weather system (and by the zonal-mean circulation) during northern winter can be very substantial: large enough to significantly reduce the CO2 condensation at polar latitudes. This could be largely responsible for the observed early spring halt in the north polar cap recession and for the presence of westerly winds near the cap edge during this season.

  12. Echocardiographic study of left atrial myxoma

    Directory of Open Access Journals (Sweden)

    Dalal J

    1979-01-01

    Full Text Available Four cases of left atrial myxoma were diagnosed pre-operatively by echocardiography. All cases showed characteristic echocardio-graphic features of variegated shadows behind the mitral valve in diastole and within the left atrium in systole. In two cases the my-xomas were surgically removed and confirmed on histology. In one case the post-operative echocardiogram showed complete dis-appearance of the abnormal shadows. Echocardiography is the most reliable method today for the diagnosis of a myxoma.

  13. Improving left spatial neglect through music scale playing.

    Science.gov (United States)

    Bernardi, Nicolò Francesco; Cioffi, Maria Cristina; Ronchi, Roberta; Maravita, Angelo; Bricolo, Emanuela; Zigiotto, Luca; Perucca, Laura; Vallar, Giuseppe

    2017-03-01

    The study assessed whether the auditory reference provided by a music scale could improve spatial exploration of a standard musical instrument keyboard in right-brain-damaged patients with left spatial neglect. As performing music scales involves the production of predictable successive pitches, the expectation of the subsequent note may facilitate patients to explore a larger extension of space in the left affected side, during the production of music scales from right to left. Eleven right-brain-damaged stroke patients with left spatial neglect, 12 patients without neglect, and 12 age-matched healthy participants played descending scales on a music keyboard. In a counterbalanced design, the participants' exploratory performance was assessed while producing scales in three feedback conditions: With congruent sound, no-sound, or random sound feedback provided by the keyboard. The number of keys played and the timing of key press were recorded. Spatial exploration by patients with left neglect was superior with congruent sound feedback, compared to both Silence and Random sound conditions. Both the congruent and incongruent sound conditions were associated with a greater deceleration in all groups. The frame provided by the music scale improves exploration of the left side of space, contralateral to the right hemisphere, damaged in patients with left neglect. Performing a scale with congruent sounds may trigger at some extent preserved auditory and spatial multisensory representations of successive sounds, thus influencing the time course of space scanning, and ultimately resulting in a more extensive spatial exploration. These findings offer new perspectives also for the rehabilitation of the disorder. © 2015 The British Psychological Society.

  14. Talk Show Science.

    Science.gov (United States)

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  15. Evaluation of left cardiac function by exercise in hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Konishi, Tokuji; Horayama, Norihisa; Hamada, Masayuki; Nakano, Takeshi; Takezawa, Hideo

    1981-01-01

    Left ventricular systolic and diastolic features at rest and exercise in hypertrophic cardiomyopathy were evaluated by Fourier analysis of blood pool scintigraphy (intracorporeal labelling with sup(99m)Tc-RBC). In the normal group (17 subjects), the left ventricular ejection fraction showed a linear increase, but no abnormality of regional ventricular wall motion, by multistage exercises. The hypertrophic cardiomyopathy group showed higher left ventricular ejection fractions at rest than those of the normal group, and in the HCM group (non-obstructive, from morphological features; 7 cases) the left ventricular ejection fraction did not increase any more when it reached a certain plateau in accordance with increased stress. In the HOCM (obstructive; 5 cases), the left ventricular ejection fraction showed a decreasing tendency as the stress was increased and also showed contractile abnormalities from the left ventricular center to the apex. Fourier analysis was effective for the evaluation of these changes. (Chiba, N.)

  16. Mechanical discordance between left atrium and left atrial appendage

    Directory of Open Access Journals (Sweden)

    Arash Khamooshian

    2018-01-01

    Full Text Available During standard transesophageal echocardiographic examinations in sinus rhythm (SR patients, the left atrial appendage (LAA is not routinely assessed with Doppler. Despite having a SR, it is still possible to have irregular activity in the LAA. This situation is even more important for SR patients where assessment of the left atrium is often foregone. We describe a case where we encountered this situation and briefly review how to assess the left atrium and its appendage in such a case scenario.

  17. Physics Reality Show

    Science.gov (United States)

    Erukhimova, Tatiana

    The attention span of K-12 students is very short; they are used to digesting information in short snippets through social media and TV. To get the students interested in physics, we created the Physics Reality Show: a series of staged short videos with duration no longer than a few minutes. Each video explains and illustrates one physics concept or law through a fast-paced sequence of physics demonstrations and experiments. The cast consists entirely of physics undergraduate students with artistic abilities and substantial experience in showing physics demonstrations at current outreach events run by the department: Physics Shows and Physics & Engineering Festival. Undergraduate students are of almost the same age as their high-school audience. They are in the best position to connect with kids and convey their fascination with physics. The PI and other faculty members who are involved in the outreach advise and coach the cast. They help students in staging the episodes and choosing the most exciting and relevant demonstrations. Supported by the APS mini-outreach Grant.

  18. [Left-handedness and health].

    Science.gov (United States)

    Milenković, Sanja; Belojević, Goran; Kocijancić, Radojka

    2010-01-01

    Hand dominance is defined as a proneness to use one hand rather than another in performing the majority of activities and this is the most obvious example of cerebral lateralization and an exclusive human characteristic. Left-handed people comprise 6-14% of the total population, while in Serbia, this percentage is 5-10%, moving from undeveloped to developed environments, where a socio-cultural pressure is less present. There is no agreement between investigators who in fact may be considered a left-handed person, about the percentage of left-handers in the population and about the etiology of left-handedness. In the scientific literature left-handedness has been related to health disorders (spine deformities, immunological disorders, migraine, neurosis, depressive psychosis, schizophrenia, insomnia, homosexuality, diabetes mellitus, arterial hypertension, sleep apnea, enuresis nocturna and Down Syndrome), developmental disorders (autism, dislexia and sttutering) and traumatism. The most reliable scientific evidences have been published about the relationship between left-handedness and spinal deformities in school children in puberty and with traumatism in general population. The controversy of other results in up-to-now investigations of health aspects of left-handedness may partly be explained by a scientific disagreement whether writing with the left hand is a sufficient criterium for left-handedness, or is it necessary to investigate other parameters for laterality assessment. Explanation of health aspects of left-handedness is dominantly based on Geschwind-Galaburda model about "anomalous" cerebral domination, as a consequence of hormonal disbalance.

  19. Flavoured Dark Matter moving left

    Science.gov (United States)

    Blanke, Monika; Das, Satrajit; Kast, Simon

    2018-02-01

    We investigate the phenomenology of a simplified model of flavoured Dark Matter (DM), with a dark fermionic flavour triplet coupling to the left-handed SU(2) L quark doublets via a scalar mediator. The DM-quark coupling matrix is assumed to constitute the only new source of flavour and CP violation, following the hypothesis of Dark Minimal Flavour Violation. We analyse the constraints from LHC searches, from meson mixing data in the K, D, and B d,s meson systems, from thermal DM freeze-out, and from direct detection experiments. Our combined analysis shows that while the experimental constraints are similar to the DMFV models with DM coupling to right-handed quarks, the multitude of couplings between DM and the SM quark sector resulting from the SU(2) L structure implies a richer phenomenology and significantly alters the resulting impact on the viable parameter space.

  20. Effects of Southern Hemisphere Wind Changes on the Meridional Overturning Circulation in Ocean Models.

    Science.gov (United States)

    Gent, Peter R

    2016-01-01

    Observations show that the Southern Hemisphere zonal wind stress maximum has increased significantly over the past 30 years. Eddy-resolving ocean models show that the resulting increase in the Southern Ocean mean flow meridional overturning circulation (MOC) is partially compensated by an increase in the eddy MOC. This effect can be reproduced in the non-eddy-resolving ocean component of a climate model, providing the eddy parameterization coefficient is variable and not a constant. If the coefficient is a constant, then the Southern Ocean mean MOC change is balanced by an unrealistically large change in the Atlantic Ocean MOC. Southern Ocean eddy compensation means that Southern Hemisphere winds cannot be the dominant mechanism driving midlatitude North Atlantic MOC variability.