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Sample records for attention evokes similar

  1. Visual evoked potentials and selective attention to points in space

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    Van Voorhis, S.; Hillyard, S. A.

    1977-01-01

    Visual evoked potentials (VEPs) were recorded to sequences of flashes delivered to the right and left visual fields while subjects responded promptly to designated stimuli in one field at a time (focused attention), in both fields at once (divided attention), or to neither field (passive). Three stimulus schedules were used: the first was a replication of a previous study (Eason, Harter, and White, 1969) where left- and right-field flashes were delivered quasi-independently, while in the other two the flashes were delivered to the two fields in random order (Bernoulli sequence). VEPs to attended-field stimuli were enhanced at both occipital (O2) and central (Cz) recording sites under all stimulus sequences, but different components were affected at the two scalp sites. It was suggested that the VEP at O2 may reflect modality-specific processing events, while the response at Cz, like its auditory homologue, may index more general aspects of selective attention.

  2. Baroreceptor activation attenuates attentional effects on pain-evoked potentials.

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    Gray, Marcus A; Minati, Ludovico; Paoletti, Giulia; Critchley, Hugo D

    2010-12-01

    Focused attention typically enhances neural nociceptive responses, reflected electroencephalographically as increased amplitude of pain-evoked event-related potentials (ERPs). Additionally, pain-evoked ERPs are attenuated by hypertension and baroreceptor activity, through as yet unclear mechanisms. There is indirect evidence that these two effects may interact, suggesting that baroreceptor-related modulation of nociception is more than a low-level gating phenomenon. To address this hypothesis, we explored in a group of healthy participants the combined effects of cue-induced expectancy and baroreceptor activity on the amplitude of pain-evoked ERPs. Brief nociceptive skin stimuli were delivered during a simple visual task; half were preceded by a visual forewarning cue, and half were unpredictable. Nociceptive stimuli were timed to coincide either with systole (maximum activation of cardiac baroreceptors) or with diastole (minimum baroreceptor activation). We observed a strong interaction between expectancy and cardiac timing for the amplitude of the P2 ERP component; no effects were observed for the N2 component. Cued stimuli were associated with larger P2 amplitude, but this effect was abolished for stimuli presented during baroreceptor activation. No cardiac timing effect was observed for un-cued stimuli. Taken together, these findings suggest a close integration of cognitive-affective aspects of expectancy and baroreceptor influences on pain, and as such may cast further light on mechanisms underlying mental and physiological contributions to clinical pain.

  3. Paying attention to orthography: A visual evoked potential study

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    Anthony Thomas Herdman

    2013-05-01

    Full Text Available In adult readers, letters and words are rapidly identified within visual networks to allow for efficient reading abilities. Neuroimaging studies of orthography have mostly used words and letter strings that recruit many hierarchical levels in reading. Understanding how single letters are processed could provide further insight into orthographic processing. The present study investigated orthographic processing using single letters and pseudoletters when adults were encouraged to pay attention to or away from orthographic features. We measured evoked potentials (EPs to single letters and pseudoletters from adults while they performed an orthographic-discrimination task (letters vs. pseudoletters, a colour-discrimination task (red vs. blue, and a target-detection task (respond to #1 and #2. Larger and later peaking N1 responses (~170ms and larger P2 responses (~250 ms occurred to pseudoletters as compared to letters. This reflected greater visual processing for pseudoletters. Dipole analyses localized this effect to bilateral fusiform and inferior temporal cortices. Moreover, this letter-pseudoletter difference was not modulated by task and thus indicates that directing attention to or away from orthographic features didn’t affect early visual processing of single letters or pseudoletters within extrastriate regions. Paying attention to orthography or colour as compared to disregarding the stimuli (target-detection task elicited selection negativities at about 175 ms, which were followed by a classical N2-P3 complexes. This indicated that the tasks sufficiently drew participant’s attention to and away from the stimuli. Together these findings revealed that visual processing of single letters and pseudoletters, in adults, appeared to be sensory-contingent and independent of paying attention to stimulus features (e.g., orthography or colour.

  4. Endogenous attention signals evoked by threshold contrast detection in human superior colliculus.

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    Katyal, Sucharit; Ress, David

    2014-01-15

    Human superior colliculus (SC) responds in a retinotopically selective manner when attention is deployed on a high-contrast visual stimulus using a discrimination task. To further elucidate the role of SC in endogenous visual attention, high-resolution fMRI was used to demonstrate that SC also exhibits a retinotopically selective response for covert attention in the absence of significant visual stimulation using a threshold-contrast detection task. SC neurons have a laminar organization according to their function, with visually responsive neurons present in the superficial layers and visuomotor neurons in the intermediate layers. The results show that the response evoked by the threshold-contrast detection task is significantly deeper than the response evoked by the high-contrast speed discrimination task, reflecting a functional dissociation of the attentional enhancement of visuomotor and visual neurons, respectively. Such a functional dissociation of attention within SC laminae provides a subcortical basis for the oculomotor theory of attention.

  5. Attentional Modulation of Visual-Evoked Potentials by Threat: Investigating the Effect of Evolutionary Relevance

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    Brown, Christopher; El-Deredy, Wael; Blanchette, Isabelle

    2010-01-01

    In dot-probe tasks, threatening cues facilitate attention to targets and enhance the amplitude of the target P1 peak of the visual-evoked potential. While theories have suggested that evolutionarily relevant threats should obtain preferential neural processing, this has not been examined empirically. In this study we examined the effects of…

  6. Evoked potential correlates of selective attention with multi-channel auditory inputs

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    Schwent, V. L.; Hillyard, S. A.

    1975-01-01

    Ten subjects were presented with random, rapid sequences of four auditory tones which were separated in pitch and apparent spatial position. The N1 component of the auditory vertex evoked potential (EP) measured relative to a baseline was observed to increase with attention. It was concluded that the N1 enhancement reflects a finely tuned selective attention to one stimulus channel among several concurrent, competing channels. This EP enhancement probably increases with increased information load on the subject.

  7. Effects of overt and covert attention on the steady-state visual evoked potential.

    Science.gov (United States)

    Walter, Sabrina; Quigley, Cliodhna; Andersen, Søren K; Mueller, Matthias M

    2012-06-21

    Flickering stimuli evoke an oscillatory brain response with the same frequency as the driving stimulus, the so-called steady-state visual evoked potential (SSVEP). SSVEPs are robust brain signals whose amplitudes are enhanced with attention and thus play a major role in the development and use of non-invasive Brain-Computer Interfaces (BCIs). We compared the modulation of SSVEP amplitudes when subjects directly gazed at a flickering array of static dots (overt attention) to when they covertly shifted attention to the dots keeping their eyes at central fixation. A discrimination task was performed at the attended location to ensure that subjects shifted attention as instructed. Horizontal eye movements (allowed in overt attention but to be avoided in covert attention) were monitored by the horizontal electrooculogram. Subjects' behavioural performance was significantly reduced in covert attention compared to overt attention. Correspondingly, attentional modulation of SSVEP amplitudes by overt attention was larger in magnitude than for covert attention. Overt attention also changed the topographical distribution of SSVEP amplitudes on the scalp. Stimuli elicited the largest amplitudes at central occipital electrodes when they were overtly attended and at contralateral parieto-occipital sites when they were covertly attended. Accordingly, source analysis revealed clear centrally located sources in early visual areas in overt attention, regardless of the attended visual hemifield. Taken together these results affirm that overt and covert attention have qualitatively and quantitatively different effects on SSVEP responses as well as on task performance. Moreover, our results suggest that navigating SSVEP-BCIs with overt attention is more reliable and highlight some of the challenges in developing BCIs for patients who have lost the ability to move their eyes.

  8. Similarly shaped letters evoke similar colors in grapheme-color synesthesia.

    Science.gov (United States)

    Brang, David; Rouw, Romke; Ramachandran, V S; Coulson, Seana

    2011-04-01

    Grapheme-color synesthesia is a neurological condition in which viewing numbers or letters (graphemes) results in the concurrent sensation of color. While the anatomical substrates underlying this experience are well understood, little research to date has investigated factors influencing the particular colors associated with particular graphemes or how synesthesia occurs developmentally. A recent suggestion of such an interaction has been proposed in the cascaded cross-tuning (CCT) model of synesthesia, which posits that in synesthetes connections between grapheme regions and color area V4 participate in a competitive activation process, with synesthetic colors arising during the component-stage of grapheme processing. This model more directly suggests that graphemes sharing similar component features (lines, curves, etc.) should accordingly activate more similar synesthetic colors. To test this proposal, we created and regressed synesthetic color-similarity matrices for each of 52 synesthetes against a letter-confusability matrix, an unbiased measure of visual similarity among graphemes. Results of synesthetes' grapheme-color correspondences indeed revealed that more similarly shaped graphemes corresponded with more similar synesthetic colors, with stronger effects observed in individuals with more intense synesthetic experiences (projector synesthetes). These results support the CCT model of synesthesia, implicate early perceptual mechanisms as driving factors in the elicitation of synesthetic hues, and further highlight the relationship between conceptual and perceptual factors in this phenomenon.

  9. Quantifying attentional modulation of auditory-evoked cortical responses from single-trial electroencephalography

    Directory of Open Access Journals (Sweden)

    Inyong eChoi

    2013-04-01

    Full Text Available Selective auditory attention is essential for human listeners to be able to communicate in multi-source environments. Selective attention is known to modulate the neural representation of the auditory scene, boosting the representation of a target sound relative to the background, but the strength of this modulation, and the mechanisms contributing to it, are not well understood. Here, listeners performed a behavioral experiment demanding sustained, focused spatial auditory attention while we measured cortical responses using electroencephalography (EEG. We presented three concurrent melodic streams; listeners were asked to attend and analyze the melodic contour of one of the streams, randomly selected from trial to trial. In a control task, listeners heard the same sound mixtures, but performed the contour judgment task on a series of visual arrows, ignoring all auditory streams. We found that the cortical responses could be fit as weighted sum of event-related potentials evoked by the stimulus onsets in the competing streams. The weighting to a given stream was roughly 10 dB higher when it was attended compared to when another auditory stream was attended; during the visual task, the auditory gains were intermediate. We then used a template-matching classification scheme to classify single-trial EEG results. We found that in all subjects, we could determine which stream the subject was attending significantly better than by chance. By directly quantifying the effect of selective attention on auditory cortical responses, these results reveal that focused auditory attention both suppresses the response to an unattended stream and enhances the response to an attended stream. The single-trial classification results add to the growing body of literature suggesting that auditory attentional modulation is sufficiently robust that it could be used as a control mechanism in brain-computer interfaces.

  10. Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

    Science.gov (United States)

    Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

    2015-01-01

    Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound

  11. Test-retest reliability of concurrently recorded steady-state and somatosensory evoked potentials in somatosensory sustained spatial attention.

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    Pang, Cheuk Yee; Mueller, Matthias M

    2014-07-01

    We investigated the test-retest reliability of sustained spatial attention modulation of steady-state somatosensory evoked potentials (SSSEPs) and the N140 component of the somatosensory evoked potentials (SEPs). Participants attended to one or both hands to perform a target detection task while concurrent mechanical vibrations were presented for 4500ms to both hands in two recording sessions. Results revealed that the amplitude and the attentional modulation of SSSEPs had high test-retest reliability, while the test-retest reliability for the N140 component was low. SSSEPs for stimuli with focused and divided attention had about the same amplitude. For the N140 component only the stimuli with focused attention were significantly enhanced. We found greater habituation effects for the N140 compared to SSSEP amplitudes but attentional modulation was unaffected in both signals. Given the great test-retest reliability of SSSEP amplitude modulation with attention, SSSEPs serve as an excellent tool for studying sustained spatial attention in somatosensation.

  12. Captured by the pain: pain steady-state evoked potentials are not modulated by selective spatial attention.

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    Blöchl, Maria; Franz, Marcel; Miltner, Wolfgang H R; Weiss, Thomas

    2015-04-07

    Attention has been shown to affect the neural processing of pain. However, the exact mechanisms underlying this modulation remain unknown. Here, we used a new method called pain steady-state evoked potentials (PSSEPs) to investigate whether selective spatial attention affects EEG responses to tonic painful stimuli. In general, steady-state evoked potentials reflect changes in the EEG spectrum at a certain frequency that correspond to the frequency of a train of applied stimuli. In this study, high intensity transcutaneous electrical stimulation was delivered to both hands simultaneously with 31 Hz and 37 Hz, respectively. Subject׳s attention was directed to one of the two trains of stimulation in order to detect a small gap that was occasionally interspersed into the stimulus trains. Thereby, they had to ignore the stimulation applied to the other hand. Results show that PSSEPs were induced at 31 Hz and 37 Hz at frontal and central electrodes. PSSEPs occurred contralaterally to the respective hand stimulated with that frequency. Surprisingly, the magnitude of PSSEPs was not modulated by spatial attention towards one of the two stimuli. Our results indicate that attention can hardly be shifted between two simultaneously applied tonic painful stimulations.

  13. Abnormal Attention in Autism Shown by Steady-State Visual Evoked Potentials.

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    Belmonte, Matthew

    2000-01-01

    Eight males with autism were required to shift attention between rapidly flashed targets alternating between left and right visual hemifields. When targets were separated by less than 700 ms, steady-state brain electrical response in both hemispheres was augmented and background EEG decreased for rightward shifts as compared with leftward shifts.…

  14. Acute stress alters auditory selective attention in humans independent of HPA: a study of evoked potentials.

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    Ludger Elling

    Full Text Available BACKGROUND: Acute stress is a stereotypical, but multimodal response to a present or imminent challenge overcharging an organism. Among the different branches of this multimodal response, the consequences of glucocorticoid secretion have been extensively investigated, mostly in connection with long-term memory (LTM. However, stress responses comprise other endocrine signaling and altered neuronal activity wholly independent of pituitary regulation. To date, knowledge of the impact of such "paracorticoidal" stress responses on higher cognitive functions is scarce. We investigated the impact of an ecological stressor on the ability to direct selective attention using event-related potentials in humans. Based on research in rodents, we assumed that a stress-induced imbalance of catecholaminergic transmission would impair this ability. METHODOLOGY/PRINCIPAL FINDINGS: The stressor consisted of a single cold pressor test. Auditory negative difference (Nd and mismatch negativity (MMN were recorded in a tonal dichotic listening task. A time series of such tasks confirmed an increased distractibility occurring 4-7 minutes after onset of the stressor as reflected by an attenuated Nd. Salivary cortisol began to rise 8-11 minutes after onset when no further modulations in the event-related potentials (ERP occurred, thus precluding a causal relationship. This effect may be attributed to a stress-induced activation of mesofrontal dopaminergic projections. It may also be attributed to an activation of noradrenergic projections. Known characteristics of the modulation of ERP by different stress-related ligands were used for further disambiguation of causality. The conjuncture of an attenuated Nd and an increased MMN might be interpreted as indicating a dopaminergic influence. The selective effect on the late portion of the Nd provides another tentative clue for this. CONCLUSIONS/SIGNIFICANCE: Prior studies have deliberately tracked the adrenocortical influence

  15. Response inhibition in Attention deficit disorder and neurofibromatosis type 1 – clinically similar, neurophysiologically different

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    Bluschke, Annet; von der Hagen, Maja; Papenhagen, Katharina; Roessner, Veit; Beste, Christian

    2017-01-01

    There are large overlaps in cognitive deficits occurring in attention deficit disorder (ADD) and neurodevelopmental disorders like neurofibromatosis type 1 (NF1). This overlap is mostly based on clinical measures and not on in-depth analyses of neuronal mechanisms. However, the consideration of such neuronal underpinnings is crucial when aiming to integrate measures that can lead to a better understanding of the underlying mechanisms. Inhibitory control deficits, for example, are a hallmark in ADD, but it is unclear how far there are similar deficits in NF1. We thus compared adolescent ADD and NF1 patients to healthy controls in a Go/Nogo task using behavioural and neurophysiological measures. Clinical measures of ADD-symptoms were not different between ADD and NF1. Only patients with ADD showed increased Nogo errors and reductions in components reflecting response inhibition (i.e. Nogo-P3). Early perceptual processes (P1) were changed in ADD and NF1. Clinically, patients with ADD and NF1 thus show strong similarities. This is not the case in regard to underlying cognitive control processes. This shows that in-depth analyses of neurophysiological processes are needed to determine whether the overlap between ADD and NF1 is as strong as assumed and to develop appropriate treatment strategies. PMID:28262833

  16. Similarity

    Science.gov (United States)

    Apostol, Tom M. (Editor)

    1990-01-01

    In this 'Project Mathematics! series, sponsored by the California Institute for Technology (CalTech), the mathematical concept of similarity is presented. he history of and real life applications are discussed using actual film footage and computer animation. Terms used and various concepts of size, shape, ratio, area, and volume are demonstrated. The similarity of polygons, solids, congruent triangles, internal ratios, perimeters, and line segments using the previous mentioned concepts are shown.

  17. Memory in Early Onset Bipolar Disorder and Attention-Deficit/Hyperactivity Disorder: Similarities and Differences

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    Udal, Anne H.; Oygarden, Bjorg; Egeland, Jens; Malt, Ulrik F.; Groholt, Berit

    2012-01-01

    Differentiating between early-onset bipolar disorder (BD) and attention-deficit/hyperactivity disorder (ADHD) can be difficult. Memory problems are commonly reported in BD, and forgetfulness is among the diagnostic criteria for ADHD. We compared children and adolescents with BD (n = 23), ADHD combined type (ADHD-C; n = 26), BD + ADHD-C (n = 15),…

  18. No evidence for early modulation of evoked responses in primary visual cortex to irrelevant probe stimuli presented during the attentional blink.

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    Oscar Jacoby

    Full Text Available BACKGROUND: During rapid serial visual presentation (RSVP, observers often miss the second of two targets if it appears within 500 ms of the first. This phenomenon, called the attentional blink (AB, is widely held to reflect a bottleneck in the processing of rapidly sequential stimuli that arises after initial sensory registration is complete (i.e., at a relatively late, post-perceptual stage of processing. Contrary to this view, recent fMRI studies have found that activity in the primary visual area (V1, which represents the earliest cortical stage of visual processing, is attenuated during the AB. Here we asked whether such changes in V1 activity during the AB arise in the initial feedforward sweep of stimulus input, or instead reflect the influence of feedback signals from higher cortical areas. METHODOLOGY/PRINCIPAL FINDINGS: EEG signals were recorded while participants monitored a sequential stream of distractor letters for two target digits (T1 and T2. Neural responses associated with an irrelevant probe stimulus presented simultaneously with T2 were measured using an ERP marker--the C1 component--that reflects initial perceptual processing of visual information in V1. As expected, T2 accuracy was compromised when the inter-target interval was brief, reflecting an AB deficit. Critically, however, the magnitude of the early C1 component evoked by the probe was not reduced during the AB. CONCLUSIONS/SIGNIFICANCE: Our finding that early sensory processing of irrelevant probe stimuli is not suppressed during the AB is consistent with theoretical models that assume that the bottleneck underlying the AB arises at a post-perceptual stage of processing. This suggests that reduced neural activity in V1 during the AB is driven by re-entrant signals from extrastriate areas that regulate early cortical activity via feedback connections with V1.

  19. Adjective metaphors evoke negative meanings.

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    Sakamoto, Maki; Utsumi, Akira

    2014-01-01

    Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1) adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2) although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3) negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities.

  20. 应用视觉诱发电位诊断儿童注意缺陷多动障碍%Diagnosis of Attention Deficit Hyperactivity Disorder with Visual Evoked Potential

    Institute of Scientific and Technical Information of China (English)

    蔡兰云; 周末芝; 李建华; 黄瑞兰; 胡淑珍; 钟建民

    2002-01-01

    目的探讨闪光视觉诱发电位(flash Visual Evoked Potential,FVEP)诊断儿童注意缺陷多动障碍(Attention Deficit Hyperactivity Disorder,ADHD)的临床价值. 方法对45例符合美国精神疾病诊断和统计手册第四版诊断标准(DSM-IV)的ADHD患儿(年龄6.5~13岁)进行FVEP检查,观察其主动注意状态下波幅的变化,并与44例正常儿童对照.结果ADHD组FVFP NI-P2、P2-N2波幅显著低于对照组(P<0.01).FVEP与DSM-Ⅳ的诊断符合率93.33%.结论FVEP是一种客观有效的ADHD辅助诊断方法.

  1. 选择性注意脑电成分的新模型及其应用%A New Signal Model of Selective Attention Evoked Potential and Its Primary Application

    Institute of Scientific and Technical Information of China (English)

    尧德中

    2004-01-01

    Presented is an analytic signal model Va = GVu + W with Va and Vu corresponding to the event-related potentials (ERPs) evoked by attended and unattended visual stimuli, respectively. A total least square algorithm is utilized to get the G and W, then the effect of attention is decomposed into two aspects: attention induced activities (W) and a gain control (G) of unattended. Applied to a spatial attention ERP data, an integrated concept of selective attention is suggested that the early gain amplification (G>1.0) and newly involved neuron activities (W) before 200 ms after the stimulus onset mainly aim at obtaining an improved signal/noise ratio, the late gain supression (G<1.0) and newly involved neuron activities (W) after 200 ms aim at specific cognitive processing of the selectively enhanced signal.%提出了一个新的选择性注意脑电信号分解模型Va=GVu+W,并应用总体最小二乘法(TLS)求解该模型方程.根据TLS求得的G和W,注意效应被分解成了两个方面,注意引起的脑神经活动W和注意对非注意情况脑活动的门限调控作用G.将该模型应用于空间注意ERP数据,进一步提出了选择性注意的一个新的理论框架,即在刺激后的200ms内出现的调制放大(G>1.0)和新活动成分(W)主要起改善信噪比的作用,而在200ms后出现的调制抑制(G<1.0)和新活动成分(W)则旨在对选择性增强的信号成分的特定认知处理.

  2. Neural Mechanisms of Attention

    Science.gov (United States)

    1993-05-21

    315-335). : Elsevier Science Publishers BV. Andrew, R.J. (1991). Testosterone, attention and memory. In P. Bateson (Ed.),The development and...reflects global stimulus properties. Nature, M,334-337. Gregory , S. D., Heath, J. A., & Rosenberg, M. E. (1989). Does selective attention influence...properties. Nature, 338,334-337. Gregory , S. D., Heath, J. A., & Rosenberg, M. E. (1989). Does selective attention influence the brain-stem auditory evoked

  3. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef;

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...

  4. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J;

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has onl...

  5. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J;

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

  6. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.;

    2007-01-01

    to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  7. Internal and external spatial attention examined with lateralized EEG power spectra.

    Science.gov (United States)

    Van der Lubbe, Rob H J; Bundt, Carsten; Abrahamse, Elger L

    2014-10-02

    Several authors argued that retrieval of an item from visual short term memory (internal spatial attention) and focusing attention on an externally presented item (external spatial attention) are similar. Part of the neuroimaging support for this view may be due to the employed experimental procedures. Furthermore, as internal spatial attention may have a more induced than evoked nature some effects may not have been visible in event related analyses of the electroencephalogram (EEG), which limits the possibility to demonstrate differences. In the current study, a colored frame cued which stimulus, one out of four presented in separate quadrants, required a response, which depended on the form of the cued stimulus (circle or square). Importantly, the frame occurred either before (precue), simultaneously with (simultaneous cue), or after the stimuli (postcue). The precue and simultaneous cue condition both concern external attention, while the postcue condition implies the involvement of internal spatial attention. Event-related lateralizations (ERLs), reflecting evoked effects, and lateralized power spectra (LPS), reflecting both evoked and induced effects, were determined. ERLs revealed a posterior contralateral negativity (PCN) only in the precue condition. LPS analyses on the raw EEG showed early increased contralateral theta power at posterior sites and later increased ipsilateral alpha power at occipito-temporal sites in all cue conditions. Responses were faster when the internally or externally attended location corresponded with the required response side than when not. These findings provide further support for the view that internal and external spatial attention share their underlying mechanism.

  8. Attention to Attention

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    In these years digital media and wireless networks are introduced in upper secondary schools in Denmark. This implies new “attentional objects” like updates on Facebook or tweets on Twitter within instant reach of the pupils and teachers. Also it implies new kinds of attention (awareness) like wh...

  9. A joint sparse representation-based method for double-trial evoked potentials estimation.

    Science.gov (United States)

    Yu, Nannan; Liu, Haikuan; Wang, Xiaoyan; Lu, Hanbing

    2013-12-01

    In this paper, we present a novel approach to solving an evoked potentials estimating problem. Generally, the evoked potentials in two consecutive trials obtained by repeated identical stimuli of the nerves are extremely similar. In order to trace evoked potentials, we propose a joint sparse representation-based double-trial evoked potentials estimation method, taking full advantage of this similarity. The estimation process is performed in three stages: first, according to the similarity of evoked potentials and the randomness of a spontaneous electroencephalogram, the two consecutive observations of evoked potentials are considered as superpositions of the common component and the unique components; second, making use of their characteristics, the two sparse dictionaries are constructed; and finally, we apply the joint sparse representation method in order to extract the common component of double-trial observations, instead of the evoked potential in each trial. A series of experiments carried out on simulated and human test responses confirmed the superior performance of our method.

  10. International Evoked Potentials Symposium

    CERN Document Server

    1980-01-01

    The past decade has seen great progress in the measurement of evoked potentials in man; a steady increase in our understanding of their charac­ teristics, their origins and their usefulness; and a growing application in the field of clinical diagnosis. The topic is a truly multidisciplinary one. Important research contributions have been made by workers of many different backgrounds and clinical applications span the specialities. This book represents a revised and updated version of the work originally presented at the international evoked potential symposium held in Nottingham 4-6 1978. The Nottingham Symposium provided a forum for a state-of-the-art discussion amongst workers from many different disciplines and from many different countries. For each major topic in the field an expert review set the scene for discussion of current research presentations. This format is retained in the book: the chapters in Part A provide the context in which the research presented in Part B is set. The task of selecting m...

  11. Multimodality evoked responses in the neurological assessment of the newborn.

    Science.gov (United States)

    Mercuri, E; von Siebenthal, K; Daniëls, H; Guzzetta, F; Casaer, P

    1994-09-01

    In recent years increased attention has been devoted to evoked potentials (EP) in newborns. This paper reviews the literature and data from our research group in an attempt to assess the diagnostic and prognostic value of evoked responses in the first weeks of life and their use in different age-specific clinical conditions. The results show that EP are a very sensitive measure of the integrity of the sensory pathways. They make it possible to follow normal physiological maturation and the abnormalities of development resulting from neurological lesions. Repeated measurements of visual evoked potentials and somatosensorial evoked potential are prognostically useful in term infants, but seem much more limited in preterm newborns in predicting neurodevelopmental outcome.

  12. Evoked potentials in multiple sclerosis.

    Science.gov (United States)

    Kraft, George H

    2013-11-01

    Before the development of magnetic resonance imaging (MRI), evoked potentials (EPs)-visual evoked potentials, somatosensory evoked potentials, and brain stem auditory evoked responses-were commonly used to determine a second site of disease in patients being evaluated for possible multiple sclerosis (MS). The identification of an area of the central nervous system showing abnormal conduction was used to supplement the abnormal signs identified on the physical examination-thus identifying the "multiple" in MS. This article is a brief overview of additional ways in which central nervous system (CNS) physiology-as measured by EPs-can still contribute value in the management of MS in the era of MRIs.

  13. Cortical evoked potentials recorded from the guinea pig without averaging.

    Science.gov (United States)

    Walloch, R A

    1975-01-01

    Potentials evoked by tonal pulses and recorded with a monopolar electrode on the pial surface over the auditory cortex of the guinea pig are presented. These potentials are compared with average potentials recorded in previous studies with an electrode on the dura. The potentials recorded by these two techniques have similar waveforms, peak latencies and thresholds. They appear to be generated within the same region of the cerebral cortex. As can be expected, the amplitude of the evoked potentials recorded from the pial surface is larger than that recorded from the dura. Consequently, averaging is not needed to extract the evoked potential once the dura is removed. The thresholds for the evoked cortical potential are similar to behavioral thresholds for the guinea pig at high frequencies; however, evoked potential thresholds are eleveate over behavioral thresholds at low frequencies. The removal of the dura and the direct recording of the evoked potential appears most appropriate for acute experiments. The recording of an evoked potential with dura electrodes empploying averaging procedures appears most appropriate for chronic studies.

  14. The Single Training Sample Extraction of Visual Evoked Potentials Based on Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; ZHANG Zhen; CHEN Wen-chao; QIN Bing

    2007-01-01

    Abstract.Based on the good localization characteristic of the wavelet transform both in time and frequency domain, a de-noising method based on wavelet transform is presented, which can make the extraction of visual evoked potentials in single training sample from the EEG background noise in favor of studying the changes between the single sample response happen. The information is probably related with the different function, appearance and pathologies of the brain. At the same time this method can also be used to remove those signal' s artifacts that do not appear with EP within the same scope of time or frequency. The traditional Fourier filter can hardly attain the similar result. This method is different from other wavelet de-noising methods in which different criteria are employed in choosing wavelet coefficient. It has a biggest virtue of noting the differences among the single training sample and making use of the characteristics of high time frequency resolution to reduce the effect of interference factors to a maximum extent within the time scope that EP appear. The experiment result proves that this method is not restricted by the signal-tonoise ratio of evoked potential and electroencephalograph (EEG) and even can recognize instantaneous event under the condition of lower signal-to-noise ratio, as well as recognize the samples which evoked evident response more easily. Therefore, more evident average evoked response could be achieved by de-nosing the signals obtained through averaging out the samples that can evoke evident responses than de-nosing the average of original signals. In addition, averaging methodology can dramatically reduce the number of record samples needed, thus avoiding the effect of behavior change during the recording process.This methodology pays attention to the differences among single training sample and also accomplishes the extraction of visual evoked potentials from single trainings sample. As a result, system speed and

  15. The effects of curiosity-evoking events on activity enjoyment.

    Science.gov (United States)

    Isikman, Elif; MacInnis, Deborah J; Ülkümen, Gülden; Cavanaugh, Lisa A

    2016-09-01

    Whereas prior literature has studied the positive effects of curiosity-evoking events that are integral to focal activities, we explore whether and how a curiosity-evoking event that is incidental to a focal activity induces negative outcomes for enjoyment. Four experiments and 1 field study demonstrate that curiosity about an event that is incidental to an activity in which individuals are engaged, significantly affects enjoyment of a concurrent activity. The reason why is that curiosity diverts attention away from the concurrent activity and focuses attention on the curiosity-evoking event. Thus, curiosity regarding an incidental event decreases enjoyment of a positive focal activity but increases enjoyment of a negative focal activity.

  16. Music evokes vivid autobiographical memories.

    Science.gov (United States)

    Belfi, Amy M; Karlan, Brett; Tranel, Daniel

    2016-08-01

    Music is strongly intertwined with memories-for example, hearing a song from the past can transport you back in time, triggering the sights, sounds, and feelings of a specific event. This association between music and vivid autobiographical memory is intuitively apparent, but the idea that music is intimately tied with memories, seemingly more so than other potent memory cues (e.g., familiar faces), has not been empirically tested. Here, we compared memories evoked by music to those evoked by famous faces, predicting that music-evoked autobiographical memories (MEAMs) would be more vivid. Participants listened to 30 songs, viewed 30 faces, and reported on memories that were evoked. Memories were transcribed and coded for vividness as in Levine, B., Svoboda, E., Hay, J. F., Winocur, G., & Moscovitch, M. [2002. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677-689]. In support of our hypothesis, MEAMs were more vivid than autobiographical memories evoked by faces. MEAMs contained a greater proportion of internal details and a greater number of perceptual details, while face-evoked memories contained a greater number of external details. Additionally, we identified sex differences in memory vividness: for both stimulus categories, women retrieved more vivid memories than men. The results show that music not only effectively evokes autobiographical memories, but that these memories are more vivid than those evoked by famous faces.

  17. Modality-independent reduction mechanisms of primary sensory evoked fields in a one-back task.

    Science.gov (United States)

    Hanke, David; Huonker, Ralph; Weiss, Thomas; Witte, Otto W; Götz, Theresa

    2016-01-01

    Attentional modulation of early, primary sensory components is still a topic of debate, as studies have produced conflicting results concerning the existence of a modulation within the primary somatosensory cortex and its direction. We previously showed that attention to tactile stimuli in a stream with visual stimuli leads to a reduction of primary somatosensory components when discrimination of different stimulus locations is requested. The question arises whether this effect is universal and independent from the distracting or attended modality. To test this, we compared the magnitude of primary somatosensory evoked fields (somatosensory P50m) in a one-back task after tactile finger stimulation during attention to tactile stimuli vs. auditory distraction in 28 volunteers. In comparison to acoustic distraction, we found a significantly decreased primary somatosensory activity when attending to tactile stimuli. Strikingly, similar results were produced within the auditory modality: when attention was focused on acoustic targets, primary auditory (auditory P50m) fields were lower as compared to the situation when attention was directed to the tactile stimulation. Our results clearly indicate that the type of task, independent from the modality, is actually the crucial factor for the direction of modulation of early sensory components by attention. Therefore, our finding of reduced primary sensory components in a discrimination task represents a universal effect independent from the distracting or attended modality.

  18. Thought-evoking approaches in engineering problems

    CERN Document Server

    2014-01-01

    In creating the value-added product in not distant future, it is necessary and inevitable to establish a holistic and though-evoking approach to the engineering problem, which should be at least associated with the inter-disciplinary knowledge and thought processes across the whole engineering spheres. It is furthermore desirable to integrate it with trans-disciplinary aspects ranging from manufacturing culture, through liberal-arts engineering, and industrial sociology.   The thought-evoking approach can be exemplified and typified by representative engineering problems: unveiling essential features in ‘Tangential Force Ratio and Interface Pressure’, prototype development for ‘Bio-mimetic Needle’ and application of ‘Water-jet Machining to Artificial Hip Joint’, product innovation in ‘Heat Sink for Computer’, application of ‘Graph Theory’ to similarity evaluation of production systems, leverage among reciprocity attributes in ‘Industrial and Engineering Designs for Machine Enclosure’,...

  19. Similarly shaped letters evoke similar colors in grapheme-color synesthesia

    NARCIS (Netherlands)

    Brang, D.; Rouw, R.; Ramachandran, V.S.; Coulson, S.

    2011-01-01

    Grapheme-color synesthesia is a neurological condition in which viewing numbers or letters (graphemes) results in the concurrent sensation of color. While the anatomical substrates underlying this experience are well understood, little research to date has investigated factors influencing the partic

  20. Web Similarity

    NARCIS (Netherlands)

    Cohen, A.R.; Vitányi, P.M.B.

    2015-01-01

    Normalized web distance (NWD) is a similarity or normalized semantic distance based on the World Wide Web or any other large electronic database, for instance Wikipedia, and a search engine that returns reliable aggregate page counts. For sets of search terms the NWD gives a similarity on a scale fr

  1. Evoked emotions predict food choice.

    Directory of Open Access Journals (Sweden)

    Jelle R Dalenberg

    Full Text Available In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Therefore, the focus within recent studies shifted towards using emotion-profiling methods that successfully can discriminate between products that are equally liked. However, it is unclear how well scores from emotion-profiling methods predict actual food choice and/or consumption. To test this, we proposed to decompose emotion scores into valence and arousal scores using Principal Component Analysis (PCA and apply Multinomial Logit Models (MLM to estimate food choice using liking, valence, and arousal as possible predictors. For this analysis, we used an existing data set comprised of liking and food-evoked emotions scores from 123 participants, who rated 7 unlabeled breakfast drinks. Liking scores were measured using a 100-mm visual analogue scale, while food-evoked emotions were measured using 2 existing emotion-profiling methods: a verbal and a non-verbal method (EsSense Profile and PrEmo, respectively. After 7 days, participants were asked to choose 1 breakfast drink from the experiment to consume during breakfast in a simulated restaurant environment. Cross validation showed that we were able to correctly predict individualized food choice (1 out of 7 products for over 50% of the participants. This number increased to nearly 80% when looking at the top 2 candidates. Model comparisons showed that evoked emotions better predict food choice than perceived liking alone. However, the strongest predictive strength was achieved by the combination of evoked emotions and liking. Furthermore we showed that non-verbal food-evoked emotion scores more accurately predict food choice than verbal food-evoked emotions scores.

  2. [Evoked potentials and inhalation anesthetics].

    Science.gov (United States)

    Thiel, A; Russ, W; Hempelmann, G

    1988-01-01

    Intraoperative monitoring of evoked potentials can be affected by various factors including volatile anaesthetics. These effects have to be considered in order to give correct interpretations of the obtained data. Visual evoked potentials (VEP) and auditory evoked potentials (AEP) will show strong alterations under general anaesthesia whereas brainstem auditory evoked potentials (BAEP) are slightly affected. The effects of nitrous oxide, halothane, enflurane, and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 35 healthy adult patients. pCO2 and tympanic membrane temperature were held constant. Simultaneous cervical and cortical SEP recording was performed using surface electrodes. After induction of anaesthesia SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. 10 patients received halothane at inspired concentrations of 0.5, 1.0, 1.5, and 2.0%. After nitrous oxide had been replaced by oxygen, halothane was reduced in steps of 0.5%. SEP were recorded at the end of each period (15 min). Equipotent doses of enflurane or isoflurane were administered to 15 and 10 patients, respectively. Nitrous oxide depressed early cortical SEP amplitude. Halothane, enflurane, and isoflurane caused dose dependent increases of latencies. Reduction of amplitude was most pronounced with isoflurane. Using high doses of enflurane in oxygen cortical SEP showed unusual high amplitudes associated with marked increases of latencies. Even under high concentrations of volatile anaesthetics cervical SEP were minimally affected. The effects of anaesthetic gases have to be considered when SEP are recorded intraoperatively.

  3. Attention Economies

    OpenAIRE

    Falkinger, Josef

    2003-01-01

    Attracting attention is a basic feature of economic life but no standard economic problem. A new theoretical model is developed which describes the general structure of competition for attention and characterizes equilibria. The exogenous fundamentals of an attention economy are the space of receiving subjects with their attention capacity, and the potential set of competing companies (senders) with their radiation technologies. The endogenous variables explained by the theory are equilibrium...

  4. Evoked Emotions Predict Food Choice

    NARCIS (Netherlands)

    Dalenberg, J.R.; Gutjar, S.; Horst, ter G.J.; Graaf, de C.; Renken, R.; Jager, G.

    2014-01-01

    In the current study we show that non-verbal food-evoked emotion scores significantly improve food choice prediction over merely liking scores. Previous research has shown that liking measures correlate with choice. However, liking is no strong predictor for food choice in real life environments. Th

  5. Evoked Potentials and Human Intelligence.

    Science.gov (United States)

    Ertl, John P.; Schafer, Edward W. P.

    Evidence of a relationship between the electrical responses of the human brain and psychometric measure of intelligence is presented. These involuntary cortical responses, known as average evoked potentials are considered to be the electrical signs of information processing by the brain. The time delays of these responses from presentation of a…

  6. Interactions between working memory and selective attention

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Event-related potential (ERP) was used to examine the interactions between working memory and selective attention. We combined two unrelated tasks, one requiring working memory and the other selective attention, which were performed by some undergraduates. The ERP results revealed that both congruent and incongruent stimuli in the selective attention task evoked an N400 component, reaching the peak point at around 500 ms. The N400 evoked by incongruent stimuli was more negative than that of congruent, which indicated the difference of semantic N400. Furthermore, working memory load had a significant influence on the N400 evoked by selective attention task in parietal region. And working memory load showed difference in the ERPs of working memory retrieval in central and parietal regions. The ERPs of probe under high working memory load were more positive from 350 to 550 ms post-stimulus; however, stimulus type of selective attention had no influence on working memory retrieval. The present study shows that working memory does not play a major role in the selective attention, especially in ignoring distracter, but it influences the performance of the selective attention as the background. The congruency of target and distracter in the selective attention task does not influence the working memory retrieval.

  7. Renewing the Respect for Similarity

    Directory of Open Access Journals (Sweden)

    Shimon eEdelman

    2012-07-01

    Full Text Available In psychology, the concept of similarity has traditionally evoked a mixture of respect, stemmingfrom its ubiquity and intuitive appeal, and concern, due to its dependence on the framing of the problemat hand and on its context. We argue for a renewed focus on similarity as an explanatory concept, bysurveying established results and new developments in the theory and methods of similarity-preservingassociative lookup and dimensionality reduction — critical components of many cognitive functions, aswell as of intelligent data management in computer vision. We focus in particular on the growing familyof algorithms that support associative memory by performing hashing that respects local similarity, andon the uses of similarity in representing structured objects and scenes. Insofar as these similarity-basedideas and methods are useful in cognitive modeling and in AI applications, they should be included inthe core conceptual toolkit of computational neuroscience.

  8. Similarity Scaling

    Science.gov (United States)

    Schnack, Dalton D.

    In Lecture 10, we introduced a non-dimensional parameter called the Lundquist number, denoted by S. This is just one of many non-dimensional parameters that can appear in the formulations of both hydrodynamics and MHD. These generally express the ratio of the time scale associated with some dissipative process to the time scale associated with either wave propagation or transport by flow. These are important because they define regions in parameter space that separate flows with different physical characteristics. All flows that have the same non-dimensional parameters behave in the same way. This property is called similarity scaling.

  9. Enhanced auditory evoked potentials in musicians:A review of recent findings

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Auditory evoked potentials serve as an objective mode for assessment to check the functioning of the auditory system and neuroplasticity. Literature has reported enhanced electrophysiological responses in musicians, which shows neuroplasticity in musicians. Various databases including PubMed, Google, Google Scholar and Medline were searched for references related to auditory evoked potentials in musicians from 1994 till date. Different auditory evoked potentials in musicians have been summarized in the present article. The findings of various studies may support as evidences for music-induced neuroplasticity which can be used for the treatment of various clinical disorders. The search results showed enhanced auditory evoked potentials in musicians compared to non-musicians from brainstem to cortical levels. Also, the present review showed enhanced attentive and pre-attentive skills in musicians compared to non-musicians.

  10. Linear superposition of sensory-evoked and ongoing cortical hemodynamics

    Directory of Open Access Journals (Sweden)

    Mohamad Saka

    2010-08-01

    Full Text Available Modern non-invasive brain imaging techniques utilise changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. To investigate this issue, 2-dimensional optical imaging spectroscopy was used to measure cortical hemodynamics in response to sensory stimuli in anaesthetised rodents Pre-stimulus cortical hemodynamics displayed spontaneous periodic fluctuations and as such, data from individual stimulus presentation trials were assigned to one of four groups depending on the phase angle of pre-stimulus hemodynamic fluctuations and averaged. This analysis revealed that sensory evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase angle of ongoing fluctuations at stimulus onset. To investigate the origin of this phenomenon, ‘null-trails’ were collected without stimulus presentation. Subtraction of phase averaged ‘null trials’ from their phase averaged stimulus-evoked counterparts resulted in four similar time series that resembled the mean stimulus-evoked response. These analyses suggest that linear superposition of evoked and ongoing cortical hemodynamic changes may be a property of the structure of inter-trial variability.

  11. Shifting Attention

    Science.gov (United States)

    Ingram, Jenni

    2014-01-01

    This article examines the shifts in attention and focus as one teacher introduces and explains an image that represents the processes involved in a numeric problem that his students have been working on. This paper takes a micro-analytic approach to examine how the focus of attention shifts through what the teacher and students do and say in the…

  12. Achieving Presence through Evoked Reality.

    Science.gov (United States)

    Pillai, Jayesh S; Schmidt, Colin; Richir, Simon

    2013-01-01

    The sense of "Presence" (evolving from "telepresence") has always been associated with virtual reality research and is still an exceptionally mystifying constituent. Now the study of presence clearly spans over various disciplines associated with cognition. This paper attempts to put forth a concept that argues that it's an experience of an "Evoked Reality (ER)" (illusion of reality) that triggers an "Evoked Presence (EP)" (sense of presence) in our minds. A Three Pole Reality Model is proposed to explain this phenomenon. The poles range from Dream Reality to Simulated Reality with Primary (Physical) Reality at the center. To demonstrate the relationship between ER and EP, a Reality-Presence Map is developed. We believe that this concept of ER and the proposed model may have significant applications in the study of presence, and in exploring the possibilities of not just virtual reality but also what we call "reality."

  13. Time Perception and Evoked Potentials

    Science.gov (United States)

    1988-07-01

    ARI Research Note 88-69 0 MitnS.Ktohe U.0 ... Ann-r (. Time Perception and Evoked Potentials Paul FraisseDT ( Lfniversit6 Rene Descartes E LECTE...JOHNSON 00L, [N Technical Dicctojr Cmad Research accomplished under contract for the Department of the Army C. Universite Rene Descartes , Paris )r...ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK Labrato-ire de Psychologie Experimental AREA• WORK UNIT NUMBERS Universite Rene Descartes

  14. Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

    Science.gov (United States)

    Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

    2016-01-01

    Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p 0.57 and p evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

  15. Stimulator Selection in SSVEP-Based Spatial Selective Attention Study.

    Science.gov (United States)

    Xie, Songyun; Liu, Chang; Obermayer, Klaus; Zhu, Fangshi; Wang, Linan; Xie, Xinzhou; Wang, Wei

    2016-01-01

    Steady-State Visual Evoked Potentials (SSVEPs) are widely used in spatial selective attention. In this process the two kinds of visual simulators, Light Emitting Diode (LED) and Liquid Crystal Display (LCD), are commonly used to evoke SSVEP. In this paper, the differences of SSVEP caused by these two stimulators in the study of spatial selective attention were investigated. Results indicated that LED could stimulate strong SSVEP component on occipital lobe, and the frequency of evoked SSVEP had high precision and wide range as compared to LCD. Moreover a significant difference between noticed and unnoticed frequencies in spectrum was observed whereas in LCD mode this difference was limited and selectable frequencies were also limited. Our experimental finding suggested that average classification accuracies among all the test subjects in our experiments were 0.938 and 0.853 in LED and LCD mode, respectively. These results indicate that LED simulator is appropriate for evoking the SSVEP for the study of spatial selective attention.

  16. Shared Attention.

    Science.gov (United States)

    Shteynberg, Garriy

    2015-09-01

    Shared attention is extremely common. In stadiums, public squares, and private living rooms, people attend to the world with others. Humans do so across all sensory modalities-sharing the sights, sounds, tastes, smells, and textures of everyday life with one another. The potential for attending with others has grown considerably with the emergence of mass media technologies, which allow for the sharing of attention in the absence of physical co-presence. In the last several years, studies have begun to outline the conditions under which attending together is consequential for human memory, motivation, judgment, emotion, and behavior. Here, I advance a psychological theory of shared attention, defining its properties as a mental state and outlining its cognitive, affective, and behavioral consequences. I review empirical findings that are uniquely predicted by shared-attention theory and discuss the possibility of integrating shared-attention, social-facilitation, and social-loafing perspectives. Finally, I reflect on what shared-attention theory implies for living in the digital world.

  17. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  18. Perceptual learning of acoustic noise generates memory-evoked potentials.

    Science.gov (United States)

    Andrillon, Thomas; Kouider, Sid; Agus, Trevor; Pressnitzer, Daniel

    2015-11-01

    Experience continuously imprints on the brain at all stages of life. The traces it leaves behind can produce perceptual learning [1], which drives adaptive behavior to previously encountered stimuli. Recently, it has been shown that even random noise, a type of sound devoid of acoustic structure, can trigger fast and robust perceptual learning after repeated exposure [2]. Here, by combining psychophysics, electroencephalography (EEG), and modeling, we show that the perceptual learning of noise is associated with evoked potentials, without any salient physical discontinuity or obvious acoustic landmark in the sound. Rather, the potentials appeared whenever a memory trace was observed behaviorally. Such memory-evoked potentials were characterized by early latencies and auditory topographies, consistent with a sensory origin. Furthermore, they were generated even on conditions of diverted attention. The EEG waveforms could be modeled as standard evoked responses to auditory events (N1-P2) [3], triggered by idiosyncratic perceptual features acquired through learning. Thus, we argue that the learning of noise is accompanied by the rapid formation of sharp neural selectivity to arbitrary and complex acoustic patterns, within sensory regions. Such a mechanism bridges the gap between the short-term and longer-term plasticity observed in the learning of noise [2, 4-6]. It could also be key to the processing of natural sounds within auditory cortices [7], suggesting that the neural code for sound source identification will be shaped by experience as well as by acoustics.

  19. Abdominal acupuncture reduces laser-evoked potentials in healthy subjects

    DEFF Research Database (Denmark)

    Pazzaglia, C.; Liguori, S.; Minciotti, I.

    2015-01-01

    Objective: Acupuncture is known to reduce clinical pain, although the exact mechanism is unknown. The aim of the current study was to investigate the effect of acupuncture on laser-evoked potential amplitudes and laser pain perception. Methods: In order to evaluate whether abdominal acupuncture...... is able to modify pain perception, 10 healthy subjects underwent a protocol in which laser-evoked potentials (LEPs) and laser pain perception were collected before the test (baseline), during abdominal acupuncture, and 15. min after needle removal. The same subjects also underwent a similar protocol...... in which, however, sham acupuncture without any needle penetration was used. Results: During real acupuncture, both N1 and N2/P2 amplitudes were reduced, as compared to baseline (p . < 0.01). The reduction lasted up to 15. min after needle removal. Furthermore, laser pain perception was reduced during...

  20. Conditioning effect of transcranial magnetic stimulation evoking motor-evoked potential on V-wave response.

    Science.gov (United States)

    Grosprêtre, Sidney; Martin, Alain

    2014-12-01

    The aim of this study was to examine the collision responsible for the volitional V-wave evoked by supramaximal electrical stimulation of the motor nerve during voluntary contraction. V-wave was conditioned by transcranial magnetic stimulation (TMS) over the motor cortex at several inter-stimuli intervals (ISI) during weak voluntary plantar flexions (n = 10) and at rest for flexor carpi radialis muscle (FCR; n = 6). Conditioning stimulations were induced by TMS with intensity eliciting maximal motor-evoked potential (MEPmax). ISIs used were ranging from -20 to +20 msec depending on muscles tested. The results showed that, for triceps surae muscles, conditioning TMS increased the V-wave amplitude (~ +250%) and the associated mechanical response (~ +30%) during weak voluntary plantar flexion (10% of the maximal voluntary contraction -MVC) for ISIs ranging from +6 to +18 msec. Similar effect was observed at rest for the FCR with ISI ranging from +6 to +12 msec. When the level of force was increased from 10 to 50% MVC or the conditioning TMS intensity was reduced to elicit responses of 50% of MEPmax, a significant decrease in the conditioned V-wave amplitude was observed for the triceps surae muscles, linearly correlated to the changes in MEP amplitude. The slope of this correlation, as well as the electro-mechanical efficiency, was closed to the identity line, indicating that V-wave impact at muscle level seems to be similar to the impact of cortical stimulation. All these results suggest that change in V-wave amplitude is a great index to reflect changes in cortical neural drive addressed to spinal motoneurons.

  1. EVOKED CAVERNOUS ACTIVITY: NEUROANATOMIC IMPLICATIONS

    Science.gov (United States)

    Yilmaz, Ugur; Vicars, Brenda; Yang, Claire C.

    2013-01-01

    We investigated the autonomic innervation of the penis by using evoked cavernous activity (ECA). We recruited 7 males with thoracic spinal cord injury (SCI) and sexual dysfunction and 6 males who were scheduled to have pelvic surgery (PS), specifically non-nerve-sparing radical cystoprostatectomy. In the PS subjects, ECA was performed both pre- and postoperatively. The left median nerve was electrically stimulated and ECA was recorded with two concentric electromyography needles placed into the right and left cavernous bodies. We simultaneously recorded hand and foot sympathetic skin responses (SSRs) as controls. In the SCI group, all but one subject had reproducible hand SSRs. None of these subjects had ECA or foot SSRs. All the PS subjects had reproducible ECA and SSRs, both preoperatively and postoperatively. There was no difference in the latency and amplitude measurements of ECA and SSRs in the postoperative compared to the preoperative period (p>0.05). In conclusion, ECA is absent in men with SCI above the sympathetic outflow to the genitalia. In men following radical pelvic surgery, ECA is preserved, indicating the preservation of sympathetic fibers. PMID:19609298

  2. [Intraoperative Visual Evoked Potential Monitoring].

    Science.gov (United States)

    Hayashi, Hironobu; Kawaguchi, Masahiko

    2015-05-01

    Visual evoked potential (VEP) is recorded from the back of the head, which is elicited by retinal stimulation transmitted through optic nerve, optic chiasm, optic tract lateral geniculate body, optic radiation and finally cortical visual area. VEP monitoring did not prevail since 1990s because marked intra-individual difference and instability of VEP recording limited the clinical usefulness under inhalation anesthetic management and techniques of VEP monitoring at the time. However, recent advances in techniques including a new light-stimulating device consisting of high-luminosity LEDs and induction of electroretinography to ascertain the arrival of the stimulus at the retina provided better conditions for stable VEP recording under general anesthesia. In addition, the introduction of total intravenous anesthesia using propofol is important for the successful VEP recordings because inhaled anesthetics have suppressive effect on VEP waveform. Intraoperative VEP has been considered to monitor the functional integrity of visual function during neurosurgical procedures, in which the optic pathway is at a risk of injury. Intraoperative VEP monitoring may allow us to detect reversible damage to the visual pathway intraoperatively and enable us to prevent permanent impairment.

  3. Ocular Vestibular Evoked Myogenic Potentials

    Directory of Open Access Journals (Sweden)

    Felipe, Lilian

    2014-01-01

    Full Text Available Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective To summarize recent developments in ocular VEMP testing. Results Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

  4. Single trial predictors for gating motor-imagery brain-computer interfaces based on sensorimotor rhythm and visual evoked potentials

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    Andrew eGeronimo

    2016-04-01

    Full Text Available For brain-computer interfaces (BCIs that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of ongoing processes, visual evoked responses, and voluntary modulation. We proposed to use three brain signatures for predicting success on a single trial of a BCI task. The first two features, the amplitude and phase of the pre-trial mu amplitude, were chosen as a correlate for cortical excitability. The remaining feature, related to the visually evoked response to the cue, served as a possible measure of fixation and attention to the task. Of these three features, mu rhythm amplitude over the central electrodes at the time of cue presentation and to a lesser extent the single trial visual evoked response were correlated with the success on the subsequent imagery task. Despite the potential for gating trials using these features, an offline gating simulation was limited in its ability to produce an increase in device throughput. This discrepancy highlights a distinction between the identification of predictive features, and the use of this knowledge in an online BCI. Using such a system, we cannot assume that the user will respond similarly when faced with a scenario where feedback is altered by trials that are gated on a regular basis. The results of this study suggest the possibility of using individualized, pre-task neural signatures for personalized and asynchronous (self-paced BCI applications, although these effects need to be quantified in a real-time adaptive scenario in a future study.

  5. Contralateral acoustic suppression of transient evoked otoacoustic emissions: Activation of the medial olivocochlear system

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    Komazec Zoran

    2003-01-01

    Full Text Available Medial olivocochlear pathway represents the final part of efferent acoustic pathway which comes from the superior olivary complex ending at outer hair cells. Activation of medial olivocochlear system (MOCS alters the cochlear output decreasing the travelling wave within cochlea. Stimulation of MOCS provides protection against moderate levels of noise, encoding noise signals as well as selecting hearing attention. Activation of MOCS can be performed using contralateral acoustic stimulation. The principal result of presentation of contralateral acoustic stimulation during screening of transient evoked otoacoustic emission (TEOAE is an attenuation of the TEOAE amplitude. Thirty-eight ears were examined in this study: twenty-eight ears from 14 normal-hearing adults and 10 patients with unilateral deafness. Healthy subjects were exposed to contralateral broad-band noise of various intensities (40, 30, 20 and 10 dB SL, as well as 30 dB SL pure tone stimulation (1 kHz and 4 kHz. A decrease of TEOAE amplitudes during contralateral stimulation with 40 and 30 dB SL broad-band noise and pure tones was established. This effect was a result of MOCS activation. A greater intensity of contralateral stimulation evoked greater decrease of TEOAE amplitude; stimulation with broad-band noise caused greater attenuation than with pure tone stimulation. Contralateral stimulation of deaf ears in the group with unilateral deafness was also performed. Statistically significant difference between TEOAE amplitude before and during contralateral stimulation was not established. This circumstance explains that activation of MOCS and consequent reduction of outer hair cells motility is very possibly caused by contralateral acoustic stimulation. Apart from studying physiological significance of efferent auditory system, results of this and similar studies can be used for production of hearing aids improving speech discrimination in noisy environment.

  6. Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Laser Evoked Potentials

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    Matthew David Jones

    2016-11-01

    Full Text Available Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant’s maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1 – SEPs; Experiment 2 – LEPs by increased pressure pain thresholds at biceps brachii (24.3% and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p 0.57 and p < 0.001. In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74. Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004 and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1.72 were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006. The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

  7. Visual Evoked Potentials in Rett Syndrome

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    J. Gordon Millichap

    2015-11-01

    Full Text Available Investigators from the Boston Children's Hospital recorded pattern-reversal visual evoked potentials (VEPs in Mecp2 heterozygous female mice and in 34 girls with Rett syndrome (RTT.

  8. Evoked potentials in neuroinfections in children

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    V. N. Komantsev

    2013-01-01

    Full Text Available We present the results of the neurophysiological study in which 95 children with viral encephalitis and 30 children with meningitis (age from 2 up to 17 years undergo evoked potentials investigation. Some specific features of evoked potentials in neuroinfections have been shown to correlate with the course of disease and the age of the patients. We give a description of a logistic model of predicting outcomes in such patients by complex diagnostic method. We have found that evoked potentials may be successfully implemented in correcting the therapeutic strategies. Study of evoked potentials in neuroinfections in children can define the severity and extent of lesions and help to identify subclinical dysfunction and monitor the recovery processes under the therapy.

  9. Sustained attention, attentional selectivity, and attentional capacity across the lifespan.

    Science.gov (United States)

    McAvinue, Laura P; Habekost, Thomas; Johnson, Katherine A; Kyllingsbæk, Søren; Vangkilde, Signe; Bundesen, Claus; Robertson, Ian H

    2012-11-01

    Changes in sustained attention, attentional selectivity, and attentional capacity were examined in a sample of 113 participants between the ages of 12 and 75. To measure sustained attention, we employed the sustained-attention-to-response task (Robertson, Manly, Andrade, Baddeley, & Yiend, Neuropsychologia 35:747-58, 1997), a short continuous-performance test designed to capture fluctuations in sustained attention. To measure attentional selectivity and capacity, we employed a paradigm based on the theory of visual attention (Bundesen, Psychological Review 97:523-547, 1990), which enabled the estimation of parameters related to attentional selection, perceptual threshold, visual short-term memory capacity, and processing capacity. We found evidence of age-related decline in each of the measured variables, but the declines varied markedly in terms of magnitude and lifespan trajectory. Variables relating to attentional capacity showed declines of very large effect sizes, while variables relating to attentional selectivity and sustained attention showed declines of medium to large effect sizes, suggesting that attentional control is relatively preserved in older adults. The variables relating to sustained attention followed a U-shaped, curvilinear trend, and the variables relating to attentional selectivity and capacity showed linear decline from early adulthood, providing further support for the differentiation of attentional functions.

  10. Is the effect of tinnitus on auditory steady-state response amplitude mediated by attention?

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    Eugen eDiesch

    2012-05-01

    Full Text Available Objectives: The amplitude of the auditory steady-state response (ASSR is enhanced in tinnitus. As ASSR ampli¬tude is also enhanced by attention, the effect of tinnitus on ASSR amplitude could be interpreted as an effect of attention mediated by tinnitus. As attention effects on the N1 are signi¬fi¬cantly larger than those on the ASSR, if the effect of tinnitus on ASSR amplitude were due to attention, there should be similar amplitude enhancement effects in tinnitus for the N1 component of the auditory evoked response. Methods: MEG recordings of auditory evoked responses which were previously examined for the ASSR (Diesch et al. 2010 were analysed with respect to the N1m component. Like the ASSR previously, the N1m was analysed in the source domain (source space projection. Stimuli were amplitude-modulated tones with one of three carrier fre¬quen¬cies matching the tinnitus frequency or a surrogate frequency 1½ octaves above the audio¬metric edge frequency in con¬trols, the audiometric edge frequency, and a frequency below the audio¬metric edgeResults: In the earlier ASSR study (Diesch et al., 2010, the ASSR amplitude in tinnitus patients, but not in controls, was significantly larger in the (surrogate tinnitus condition than in the edge condition. In the present study, both tinnitus patients and healthy controls show an N1m-amplitude profile identical to the one of ASSR amplitudes in healthy controls. N1m amplitudes elicited by tonal frequencies located at the audiometric edge and at the (surrogate tinnitus frequency are smaller than N1m amplitudes elicited by sub-edge tones and do not differ among each other.Conclusions: There is no N1-amplitude enhancement effect in tinnitus. The enhancement effect of tinnitus on ASSR amplitude cannot be accounted for in terms of attention induced by tinnitus.

  11. Temporal dynamics of visual attention measured with event-related potentials.

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    Yoshiyuki Kashiwase

    Full Text Available How attentional modulation on brain activities determines behavioral performance has been one of the most important issues in cognitive neuroscience. This issue has been addressed by comparing the temporal relationship between attentional modulations on neural activities and behavior. Our previous study measured the time course of attention with amplitude and phase coherence of steady-state visual evoked potential (SSVEP and found that the modulation latency of phase coherence rather than that of amplitude was consistent with the latency of behavioral performance. In this study, as a complementary report, we compared the time course of visual attention shift measured by event-related potentials (ERPs with that by target detection task. We developed a novel technique to compare ERPs with behavioral results and analyzed the EEG data in our previous study. Two sets of flickering stimulus at different frequencies were presented in the left and right visual hemifields, and a target or distracter pattern was presented randomly at various moments after an attention-cue presentation. The observers were asked to detect targets on the attended stimulus after the cue. We found that two ERP components, P300 and N2pc, were elicited by the target presented at the attended location. Time-course analyses revealed that attentional modulation of the P300 and N2pc amplitudes increased gradually until reaching a maximum and lasted at least 1.5 s after the cue onset, which is similar to the temporal dynamics of behavioral performance. However, attentional modulation of these ERP components started later than that of behavioral performance. Rather, the time course of attentional modulation of behavioral performance was more closely associated with that of the concurrently recorded SSVEPs analyzed. These results suggest that neural activities reflected not by either the P300 or N2pc, but by the SSVEPs, are the source of attentional modulation of behavioral performance.

  12. Transiently Evoked Otoacoustic Emissions in Children with Otitis Media with Effusion

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    Dimitris G. Balatsouras

    2012-01-01

    Full Text Available Introduction. Otitis media with effusion is a common pediatric disease whose diagnosis is based on pneumatic otoscopy, pure-tone audiometry, and tympanometry. The aim of this study was to evaluate transiently evoked otoacoustic emissions in the diagnosis of otitis media with effusion as compared to tympanometry. Patients and Methods. 38 children with bilateral otitis media with effusion were studied. 40 normal children of similar age and sex were used as controls. All subjects underwent pneumatic otoscopy, standard pure-tone audiometry, tympanometry, and transiently evoked otoacoustic emissions. Results. In the group of children with bilateral otitis media, transiently evoked otoacoustic emissions were absent in 51 ears (67%. In the remaining 25 ears (33% the mean emission amplitude was reduced, as compared to the mean value of the control group. Conclusions. Transiently evoked otoacoustic emissions should be included in the diagnostic workup of otitis media with effusion because it is a fast, reliable, and objective test. Transiently evoked otoacoustic emissions should always be used in conjunction with tympanometry, because a more meaningful interpretation of transiently evoked otoacoustic emissions measures is possible.

  13. Increasing Pain Sensation Eliminates the Inhibitory Effect of Depression on Evoked Pain in Rats

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    Wang, Ning; Li, Sheng-Guang; Lin, Xiao-Xiao; Su, Yuan-Lin; Qi, Wei-Jing; Wang, Jin-Yan; Luo, Fei

    2016-01-01

    Although previous studies have suggested that depression may be associated with inhibition of evoked pain but facilitation of spontaneous pain, the mechanisms underlying these relationships are unclear. The present study investigated whether the difference between evoked and spontaneous pain on sensory (descending inhibition) and affective (avoidance motivation) components contributes to the divergent effects of depression on them. Depressive-like behavior was produced in male Wistar rats by unpredictable chronic mild stress (UCMS). Tone-laser conditioning and formalin-induced conditioned place avoidance (F-CPA) were used to explore avoidance motivation in evoked and spontaneous pain, respectively. Behavioral pharmacology experiments were conducted to examine descending inhibition of both evoked (thermal stimulation) and spontaneous pain behavior (formalin pain). The results revealed that the inhibitory effect of depression on evoked pain was eliminated following repeated thermal stimuli. Avoidance behavior in the tone-laser conditioning task was reduced in UCMS rats, relative to controls. However, avoidance motivation for formalin pain in the UCMS group was similar to controls. 5-HT1A receptor antagonism interfered with inhibition of pain responses over time. The present study demonstrated that the inhibitory effect of depression on evoked pain dissipates with increased nociception and that the sensory-discriminative and affective-motivational components of pain are jointly involved in the divergent effects of depression on pain. PMID:27733820

  14. Characterization of Motor and Somatosensory Evoked Potentials in the Yucatan Micropig Using Transcranial and Epidural Stimulation.

    Science.gov (United States)

    Benavides, Francisco D; Santamaria, Andrea J; Bodoukhin, Nikita; Guada, Luis G; Solano, Juan P; Guest, James D

    2016-11-28

    Yucatan micropigs have brain and spinal cord dimensions similar to humans and are useful for certain spinal cord injury (SCI) translational studies. Micropigs are readily trained in behavioral tasks, allowing consistent testing of locomotor loss and recovery. However, there has been little description of their motor and sensory pathway neurophysiology. We established methods to assess motor and sensory cortical evoked potentials in the anesthetized, uninjured state. We also evaluated epidurally evoked motor and sensory stimuli from the T6 and T9 levels, spanning the intended contusion injury epicenter. Response detection frequency, mean latency and amplitude values, and variability of evoked potentials were determined. Somatosensory evoked potentials were reliable and best detected during stimulation of peripheral nerve and epidural stimulation by referencing the lateral cortex to midline Fz. The most reliable hindlimb motor evoked potential (MEP) occurred in tibialis anterior. We found MEPs in forelimb muscles in response to thoracic epidural stimulation likely generated from propriospinal pathways. Cranially stimulated MEPs were easier to evoke in the upper limbs than in the hindlimbs. Autopsy studies revealed substantial variations in cortical morphology between animals. This electrophysiological study establishes that neurophysiological measures can be reliably obtained in micropigs in a time frame compatible with other experimental procedures, such as SCI and transplantation. It underscores the need to better understand the motor control pathways, including the corticospinal tract, to determine which therapeutics are suitable for testing in the pig model.

  15. Cervical intraspinal microstimulation evokes robust forelimb movements before and after injury

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    Sunshine, Michael D.; Cho, Frances S.; Lockwood, Danielle R.; Fechko, Amber S.; Kasten, Michael R.; Moritz, Chet T.

    2013-06-01

    Objective. Intraspinal microstimulation (ISMS) is a promising method for reanimating paralyzed limbs following neurological injury. ISMS within the cervical and lumbar spinal cord is capable of evoking a variety of highly-functional movements prior to injury, but the ability of ISMS to evoke forelimb movements after cervical spinal cord injury is unknown. Here we examine the forelimb movements and muscles activated by cervical ISMS both before and after contusion injury. Approach. We documented the forelimb muscles activated and movements evoked via systematic stimulation of the rodent cervical spinal cord both before injury and three, six and nine weeks following a moderate C4/C5 lateralized contusion injury. Animals were anesthetized with isoflurane to permit construction of somatotopic maps of evoked movements and quantify evoked muscle synergies between cervical segments C3 and T1. Main results. When ISMS was delivered to the cervical spinal cord, a variety of responses were observed at 68% of locations tested, with a spatial distribution that generally corresponded to the location of motor neuron pools. Stimulus currents required to achieve movement and the number of sites where movements could be evoked were unchanged by spinal cord injury. A transient shift toward extension-dominated movements and restricted muscle synergies were observed at three and six weeks following injury, respectively. By nine weeks after injury, however, ISMS-evoked patterns were similar to spinally-intact animals. Significance. The results demonstrate the potential for cervical ISMS to reanimate hand and arm function following spinal cord injury. Robust forelimb movements can be evoked both before and during the chronic stages of recovery from a clinically relevant and sustained cervical contusion injury.

  16. Cognitive Evoked Potential Measurement, P300, in a group of healthy Colombian individuals

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    Natalia Gutiérrez Giraldo

    2013-05-01

    Full Text Available Cognitive evoked potentials are electrophysiological measurements of cognitive functions. Cognitivepotential P300 is specifically related to attention processes. Objetive: the aim of this studywas to establish reference values for latency and amplitude of P300 wave in the Colombian population and determine their variability with age, gender and education of the subjects. Methods:we studied 122 healthy subjects between 6 and 80 years, are practical potential measurementmethodology as odd-ball, in leads Cz and Pz. Results: we were able to establish reference valuesfor different age groups, and statistical significance was found with which the latency of P300wave increases with the age of individuals, and instead thereof the amplitude tends to decrease.Similarly to correlate latency and amplitude was shown an inverse relationship between them.Conclusions: no differences were found for latency and wave amplitude, gender-related or schoolsubjects as well as no difference was found when measuring the Pz derivation obtained comparedwith the wave in lead Cz.

  17. Laser-evoked potentials in primary headaches and cranial neuralgias.

    Science.gov (United States)

    de Tommaso, Marina

    2008-09-01

    Using neurophysiological methods to explore nociceptive pathways may improve knowledge of the functional changes subtending pain processing in the different forms of headache and facial pain. Laser-evoked potentials (LEPs) are a reliable neurophysiological assay for the clinical assessment of pain syndromes. Reduced amplitude of LEPs seems to characterize trigeminal neuralgia and painful temporomandibular disorders, suggesting the neuropathic origin of pain. In tension-type headache, as well as in fibromyalgia, enhanced pericranial LEP amplitude suggests the psychogenic origin of pain. In migraine, a normal amplitude of basal LEPs with reduced habituation and altered attentive modulation seems to express a general dysfunction of cortical pain processing, which may also contribute, other than to predispose, to the persistence of migraine. LEPs may be employed in the clinical evaluation of the neurophysiological and psychophysiological aspects of pain in the different forms of headaches and facial pain to improve the therapeutic approach and provide an objective measure of treatment efficacy.

  18. Brain correlates of music-evoked emotions.

    Science.gov (United States)

    Koelsch, Stefan

    2014-03-01

    Music is a universal feature of human societies, partly owing to its power to evoke strong emotions and influence moods. During the past decade, the investigation of the neural correlates of music-evoked emotions has been invaluable for the understanding of human emotion. Functional neuroimaging studies on music and emotion show that music can modulate activity in brain structures that are known to be crucially involved in emotion, such as the amygdala, nucleus accumbens, hypothalamus, hippocampus, insula, cingulate cortex and orbitofrontal cortex. The potential of music to modulate activity in these structures has important implications for the use of music in the treatment of psychiatric and neurological disorders.

  19. [Effect of sleep deprivation on visual evoked potentials and brain stem auditory evoked potentials in epileptics].

    Science.gov (United States)

    Urumova, L T; Kovalenko, G A; Tsunikov, A I; Sumskiĭ, L I

    1984-01-01

    The article reports on the first study of the evoked activity of the brain in epileptic patients (n = 20) following sleep deprivation. An analysis of the data obtained has revealed a tendency to the shortening of the peak latent intervals of visual evoked potentials in the range of 100-200 mu sec and the V component and the interpeak interval III-V of evoked auditory trunk potentials in patients with temporal epilepsy. The phenomenon may indicate the elimination of stabilizing control involving the specific conductive pathways and, possibly, an accelerated conduction of a specific sensor signal.

  20. Bilingualism increases neural response consistency and attentional control: evidence for sensory and cognitive coupling.

    Science.gov (United States)

    Krizman, Jennifer; Skoe, Erika; Marian, Viorica; Kraus, Nina

    2014-01-01

    Auditory processing is presumed to be influenced by cognitive processes - including attentional control - in a top-down manner. In bilinguals, activation of both languages during daily communication hones inhibitory skills, which subsequently bolster attentional control. We hypothesize that the heightened attentional demands of bilingual communication strengthens connections between cognitive (i.e., attentional control) and auditory processing, leading to greater across-trial consistency in the auditory evoked response (i.e., neural consistency) in bilinguals. To assess this, we collected passively-elicited auditory evoked responses to the syllable [da] in adolescent Spanish-English bilinguals and English monolinguals and separately obtained measures of attentional control and language ability. Bilinguals demonstrated enhanced attentional control and more consistent brainstem and cortical responses. In bilinguals, but not monolinguals, brainstem consistency tracked with language proficiency and attentional control. We interpret these enhancements in neural consistency as the outcome of strengthened attentional control that emerged from experience communicating in two languages.

  1. Social reward shapes attentional biases.

    Science.gov (United States)

    Anderson, Brian A

    2016-01-01

    Paying attention to stimuli that predict a reward outcome is important for an organism to survive and thrive. When visual stimuli are associated with tangible, extrinsic rewards such as money or food, these stimuli acquire high attentional priority and come to automatically capture attention. In humans and other primates, however, many behaviors are not motivated directly by such extrinsic rewards, but rather by the social feedback that results from performing those behaviors. In the present study, I examine whether positive social feedback can similarly influence attentional bias. The results show that stimuli previously associated with a high probability of positive social feedback elicit value-driven attentional capture, much like stimuli associated with extrinsic rewards. Unlike with extrinsic rewards, however, such stimuli also influence task-specific motivation. My findings offer a potential mechanism by which social reward shapes the information that we prioritize when perceiving the world around us.

  2. Color Evoked Potentials in Adults and Infants.

    Science.gov (United States)

    White, Carroll T.; And Others

    This paper discusses recent studies of the adult visual evoked potential (VEP) which have indicated that specific components of the complex waveform obtained are related to the three basic color processes, and that these components interact in ways that seem to agree with opponent-colors phenomena. The components identified as being related to the…

  3. Cortical correlates of an attentional bias to painful and innocuous somatic stimuli in children with recurrent abdominal pain.

    Science.gov (United States)

    Hermann, Christiane; Zohsel, Katrin; Hohmeister, Johanna; Flor, Herta

    2008-06-01

    Recurrent abdominal pain (RAP) is a common gastrointestinal problem during childhood. It is not only a pediatric health problem, but may represent a risk factor for chronic pain, psychosomatic symptoms, and psychopathological problems later in life. Alterations in central pain processing and an attentional bias to potentially aversive somatic sensations could contribute to the unfavorable outcome of RAP during childhood. Fourteen children with RAP and 15 control children (age: 10-15 year) participated in an attentional task. Children had to respond to rare targets (tones) and ignore frequent either painful (pain threshold) or non-painful mechanical stimuli delivered at the hand. Event-related cortical potentials in response to the somatic stimuli and the tones were measured and stimulus intensity ratings, reaction time and number of errors were obtained. Painful as compared to non-painful stimuli elicited significantly larger N1, P2 and P3 components of the somatosensory-evoked potential (SEP) in all children. The RAP children responded with a significantly larger P3 to both painful and non-painful stimuli. No group differences were found for the auditory-evoked potentials. Perceived stimulus and pain intensity, reaction time and number of errors did not differ between groups. Similar to findings in adults with functional gastrointestinal disorders (FGIDs), children with RAP did not show somatic hyperalgesia as revealed by unaltered pain thresholds and middle latency pain-evoked SEPs. However, they displayed an attentional bias to painful and non-painful (innocuous) somatic stimuli as indicated by an enhanced P3. This may represent an important mechanism not only for the maintenance of RAP, but also for the development of psychosomatic symptoms.

  4. Methylglyoxal evokes pain by stimulating TRPA1.

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    David A Andersson

    Full Text Available Diabetic neuropathy is a severe complication of long-standing diabetes and one of the major etiologies of neuropathic pain. Diabetes is associated with an increased formation of reactive oxygen species and the electrophilic dicarbonyl compound methylglyoxal (MG. Here we show that MG stimulates heterologously expressed TRPA1 in CHO cells and natively expressed TRPA1 in MDCK cells and DRG neurons. MG evokes [Ca(2+]i-responses in TRPA1 expressing DRG neurons but is without effect in neurons cultured from Trpa1(-/- mice. Consistent with a direct, intracellular action, we show that methylglyoxal is significantly more potent as a TRPA1 agonist when applied to the intracellular face of excised membrane patches than to intact cells. Local intraplantar administration of MG evokes a pain response in Trpa1(+/+ but not in Trpa1(-/- mice. Furthermore, persistently increased MG levels achieved by two weeks pharmacological inhibition of glyoxalase-1 (GLO-1, the rate-limiting enzyme responsible for detoxification of MG, evokes a progressive and marked thermal (cold and heat and mechanical hypersensitivity in wildtype but not in Trpa1(-/- mice. Our results thus demonstrate that TRPA1 is required both for the acute pain response evoked by topical MG and for the long-lasting pronociceptive effects associated with elevated MG in vivo. In contrast to our observations in DRG neurons, MG evokes indistinguishable [Ca(2+]i-responses in pancreatic β-cells cultured from Trpa1(+/+ and Trpa1(-/- mice. In vivo, the TRPA1 antagonist HC030031 impairs glucose clearance in the glucose tolerance test both in Trpa1(+/+ and Trpa1(-/- mice, indicating a non-TRPA1 mediated effect and suggesting that results obtained with this compound should be interpreted with caution. Our results show that TRPA1 is the principal target for MG in sensory neurons but not in pancreatic β-cells and that activation of TRPA1 by MG produces a painful neuropathy with the behavioral hallmarks of diabetic

  5. Effects of etidocaine administered epidurally on changes in somatosensory evoked potentials after dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Hansen, O B; Kehlet, H;

    1991-01-01

    The effect of lumbar epidural anesthesia with similar volumes (approximately 20 ml) of 1% and 1.5% etidocaine on early (less than 0.5 seconds) somatosensory evoked potentials (SEPs) to electrical stimulation of the S1, L1, and T10 dermatomes was examined in two groups of ten patients...

  6. Effect of epidural 0.25% bupivacaine on somatosensory evoked potentials to dermatomal stimulation

    DEFF Research Database (Denmark)

    Lund, C; Hansen, O B; Kehlet, H

    1989-01-01

    The effect of lumbar epidural analgesia with similar volumes (about 25 ml) of 0.25% and 0.5% bupivacaine on early (less than 0.5 seconds) somatosensory evoked potentials (SEPs) to electrical stimulation of the S1, L1, and T10 dermatomes was examined in two groups of ten patients. Level of sensory...

  7. Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder

    NARCIS (Netherlands)

    Burke, Sarah M; Menks, Willeke M; Cohen-Kettenis, Peggy T; Klink, Daniel T; Bakker, J.

    2014-01-01

    Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to

  8. Modulation of auditory evoked responses to spectral and temporal changes by behavioral discrimination training

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    Okamoto Hidehiko

    2009-12-01

    Full Text Available Abstract Background Due to auditory experience, musicians have better auditory expertise than non-musicians. An increased neocortical activity during auditory oddball stimulation was observed in different studies for musicians and for non-musicians after discrimination training. This suggests a modification of synaptic strength among simultaneously active neurons due to the training. We used amplitude-modulated tones (AM presented in an oddball sequence and manipulated their carrier or modulation frequencies. We investigated non-musicians in order to see if behavioral discrimination training could modify the neocortical activity generated by change detection of AM tone attributes (carrier or modulation frequency. Cortical evoked responses like N1 and mismatch negativity (MMN triggered by sound changes were recorded by a whole head magnetoencephalographic system (MEG. We investigated (i how the auditory cortex reacts to pitch difference (in carrier frequency and changes in temporal features (modulation frequency of AM tones and (ii how discrimination training modulates the neuronal activity reflecting the transient auditory responses generated in the auditory cortex. Results The results showed that, additionally to an improvement of the behavioral discrimination performance, discrimination training of carrier frequency changes significantly modulates the MMN and N1 response amplitudes after the training. This process was accompanied by an attention switch to the deviant stimulus after the training procedure identified by the occurrence of a P3a component. In contrast, the training in discrimination of modulation frequency was not sufficient to improve the behavioral discrimination performance and to alternate the cortical response (MMN to the modulation frequency change. The N1 amplitude, however, showed significant increase after and one week after the training. Similar to the training in carrier frequency discrimination, a long lasting

  9. Stimulator Selection in SSVEP-Based Spatial Selective Attention Study

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    Songyun Xie

    2016-01-01

    Full Text Available Steady-State Visual Evoked Potentials (SSVEPs are widely used in spatial selective attention. In this process the two kinds of visual simulators, Light Emitting Diode (LED and Liquid Crystal Display (LCD, are commonly used to evoke SSVEP. In this paper, the differences of SSVEP caused by these two stimulators in the study of spatial selective attention were investigated. Results indicated that LED could stimulate strong SSVEP component on occipital lobe, and the frequency of evoked SSVEP had high precision and wide range as compared to LCD. Moreover a significant difference between noticed and unnoticed frequencies in spectrum was observed whereas in LCD mode this difference was limited and selectable frequencies were also limited. Our experimental finding suggested that average classification accuracies among all the test subjects in our experiments were 0.938 and 0.853 in LED and LCD mode, respectively. These results indicate that LED simulator is appropriate for evoking the SSVEP for the study of spatial selective attention.

  10. Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control

    DEFF Research Database (Denmark)

    Jensen-Dahm, Christina; Madsen, Caspar Skau; Waldemar, Gunhild

    2016-01-01

    OBJECTIVE: Clinical studies have found that patients with Alzheimer's disease report pain of less intensity and with a lower affective response, which has been thought to be due to altered pain processing. The authors wished to examine the cerebral processing of non-painful and painful stimuli...... using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls. DESIGN: Case-control study SETTING AND SUBJECTS: Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls...... threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups. CONCLUSIONS: The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease....

  11. Pupil diameter reflects uncertainty in attentional selection during visual search

    Directory of Open Access Journals (Sweden)

    Joy J. Geng

    2015-08-01

    Full Text Available Pupil diameter has long been used as a metric of cognitive processing. However, recent advances suggest that the cognitive sources of change in pupil size may reflect LC-NE function and the calculation of unexpected uncertainty in decision processes (Aston-Jones & Cohen, 2005b; Yu & Dayan, 2005. In the current experiments, we explored the role of uncertainty in attentional selection on task-evoked changes in pupil diameter during visual search. We found that task-evoked changes in pupil diameter were related to uncertainty during attentional selection as measured by reaction time and performance accuracy (Experiments 1-2. Control analyses demonstrated that the results are unlikely to be due to error monitoring or response uncertainty. Our results suggest that pupil diameter can be used as an implicit metric of uncertainty in ongoing attentional selection requiring effortful control processes.

  12. Video-Based Eye Tracking to Detect the Attention Shift: A Computer Classroom Context-Aware System

    Science.gov (United States)

    Kuo, Yung-Lung; Lee, Jiann-Shu; Hsieh, Min-Chai

    2014-01-01

    Eye and head movements evoked in response to obvious visual attention shifts. However, there has been little progress on the causes of absent-mindedness so far. The paper proposes an attention awareness system that captures the conditions regarding the interaction of eye gaze and head pose under various attentional switching in computer classroom.…

  13. Subcortical evoked activity and motor enhancement in Parkinson's disease

    Science.gov (United States)

    Anzak, Anam; Tan, Huiling; Pogosyan, Alek; Khan, Sadaquate; Javed, Shazia; Gill, Steven S.; Ashkan, Keyoumars; Akram, Harith; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Green, Alexander L.; Aziz, Tipu; Brown, Peter

    2016-01-01

    Enhancements in motor performance have been demonstrated in response to intense stimuli both in healthy subjects and in the form of ‘paradoxical kinesis’ in patients with Parkinson's disease. Here we identify a mid-latency evoked potential in local field potential recordings from the region of the subthalamic nucleus, which scales in amplitude with both the intensity of the stimulus delivered and corresponding enhancements in biomechanical measures of maximal handgrips, independent of the dopaminergic state of our subjects with Parkinson's disease. Recordings of a similar evoked potential in the related pedunculopontine nucleus – a key component of the reticular activating system – provide support for this neural signature in the subthalmic nucleus being a novel correlate of ascending arousal, propagated from the reticular activating system to exert an ‘energizing’ influence on motor circuitry. Future manipulation of this system linking arousal and motor performance may provide a novel approach for the non-dopaminergic enhancement of motor performance in patients with hypokinetic disorders such as Parkinson's disease. PMID:26687971

  14. Attention and Olfactory Consciousness

    OpenAIRE

    Andreas eKeller

    2011-01-01

    Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to ...

  15. Music training relates to the development of neural mechanisms of selective auditory attention.

    Science.gov (United States)

    Strait, Dana L; Slater, Jessica; O'Connell, Samantha; Kraus, Nina

    2015-04-01

    Selective attention decreases trial-to-trial variability in cortical auditory-evoked activity. This effect increases over the course of maturation, potentially reflecting the gradual development of selective attention and inhibitory control. Work in adults indicates that music training may alter the development of this neural response characteristic, especially over brain regions associated with executive control: in adult musicians, attention decreases variability in auditory-evoked responses recorded over prefrontal cortex to a greater extent than in nonmusicians. We aimed to determine whether this musician-associated effect emerges during childhood, when selective attention and inhibitory control are under development. We compared cortical auditory-evoked variability to attended and ignored speech streams in musicians and nonmusicians across three age groups: preschoolers, school-aged children and young adults. Results reveal that childhood music training is associated with reduced auditory-evoked response variability recorded over prefrontal cortex during selective auditory attention in school-aged child and adult musicians. Preschoolers, on the other hand, demonstrate no impact of selective attention on cortical response variability and no musician distinctions. This finding is consistent with the gradual emergence of attention during this period and may suggest no pre-existing differences in this attention-related cortical metric between children who undergo music training and those who do not.

  16. Early visual evoked potentials in callosal agenesis.

    Science.gov (United States)

    Barr, Melodie S; Hamm, Jeff P; Kirk, Ian J; Corballis, Michael C

    2005-11-01

    Three participants with callosal agenesis and 12 neurologically normal participants were tested on a simple reaction time task, with visual evoked potentials collected using a high-density 128-channel system. Independent-components analyses were performed on the averaged visual evoked potentials to isolate the components of interest. Contrary to previous research with acallosals, evidence of ipsilateral activation was present in all 3 participants. Although ipsilateral visual components were present in all 4 unilateral conditions in the 2 related acallosal participants, in the 3rd, these were present only in the crossed visual field-hand conditions and not in the uncrossed conditions. Suggestions are made as to why these results differ from earlier findings and as to the neural mechanisms facilitating this ipsilateral activation.

  17. Changes of brainstem auditory and somatosensory evoked

    Institute of Scientific and Technical Information of China (English)

    Yang Jian

    2000-01-01

    Objective: to investigate the characteristics and clinical value of evoked potentials in late infantile form of metachromatic leukodystrophy. Methods: Brainstem auditory, and somatosensory evoked potentials were recorded in 6 patients, and compared with the results of CT scan. Results: All of the 6 patients had abnormal results of BAEP and MNSEP. The main abnormal parameters in BAEP were latency prolongation in wave I, inter-peak latency prolongation in Ⅰ-Ⅲ and Ⅰ-Ⅴ. The abnormal features of MNSEP were low amplitude and absence of wave N9, inter-Peak latency prolongation in Ng-N13 and N13-N20, but no significant change of N20 amplitude. The results also revealed that abnormal changes in BAEP and MNSEP were earlier than that in CT. Conclusion: The detection of BAEP and MNSEP in late infantile form of metachromatic leukodystrophy might early reveal the abnormality of conductive function in nervous system and might be a useful method in diagnosis.

  18. Modeling auditory evoked potentials to complex stimuli

    DEFF Research Database (Denmark)

    Rønne, Filip Munch

    The auditory evoked potential (AEP) is an electrical signal that can be recorded from electrodes attached to the scalp of a human subject when a sound is presented. The signal is considered to reflect neural activity in response to the acoustic stimulation and is a well established clinical...... clinically and in research towards using realistic and complex stimuli, such as speech, to electrophysiologically assess the human hearing. However, to interpret the AEP generation to complex sounds, the potential patterns in response to simple stimuli needs to be understood. Therefore, the model was used...... to simulate auditory brainstem responses (ABRs) evoked by classic stimuli like clicks, tone bursts and chirps. The ABRs to these simple stimuli were compared to literature data and the model was shown to predict the frequency dependence of tone-burst ABR wave-V latency and the level-dependence of ABR wave...

  19. Evoked Effective Connectivity of the Human Neocortex

    OpenAIRE

    Entz, László; Tóth, Emília; Keller, Corey J.; Bickel, Stephan; Groppe, David M.; Fabó, Dániel; Kozák, Lajos R.; Eroőss, Loránd; Ulbert, István; Mehta, Ashesh D.

    2014-01-01

    The role of cortical connectivity in brain function and pathology is increasingly being recognized. While in vivo magnetic resonance imaging studies have provided important insights into anatomical and functional connectivity, these methodologies are limited in their ability to detect electrophysiological activity and the causal relationships that underlie effective connectivity. Here, we describe results of cortico-cortical evoked potential (CCEP) mapping using single pulse electrical stimul...

  20. Brain stem evoked response audiometry A Review

    OpenAIRE

    Balasubramanian Thiagarajan

    2015-01-01

    Brain stem evoked response audiometry (BERA) is a useful objective assessement of hearing. Major advantage of this procedure is its ability to test even infants in whom conventional audiometry may not be useful. This investigation can be used as a screening test for deafness in high risk infants. Early diagnosis and rehabilitation will reduce disability in these children. This article attempts to review the published literature on this subject. Methadology: Internet search using goog...

  1. Auditory evoked potentials and multiple sclerosis

    OpenAIRE

    Carla Gentile Matas; Sandro Luiz de Andrade Matas; Caroline Rondina Salzano de Oliveira; Isabela Crivellaro Gonçalves

    2010-01-01

    Multiple sclerosis (MS) is an inflammatory, demyelinating disease that can affect several areas of the central nervous system. Damage along the auditory pathway can alter its integrity significantly. Therefore, it is important to investigate the auditory pathway, from the brainstem to the cortex, in individuals with MS. OBJECTIVE: The aim of this study was to characterize auditory evoked potentials in adults with MS of the remittent-recurrent type. METHOD: The study comprised 25 individuals w...

  2. Brainstem auditory evoked response: application in neurology

    Directory of Open Access Journals (Sweden)

    Carlos A. M. Guerreiro

    1982-03-01

    Full Text Available The tecnique that we use for eliciting brainstem auditory evoked responses (BAERs is described. BAERs are a non-invasive and reliable clinical test when carefully performed. This test is indicated in the evaluation of disorders which may potentially involve the brainstem such as coma, multiple sclerosis posterior fossa tumors and others. Unsuspected lesions with normal radiologic studies (including CT-scan can be revealed by the BAER.

  3. Attention and Olfactory Consciousness

    Directory of Open Access Journals (Sweden)

    Andreas eKeller

    2011-12-01

    Full Text Available Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to the discussion: attention to the olfactory modality. I will first clarify the position of attention to smells in a general taxonomy of attention. I will then review the mechanisms and neuroanatomy of attention and consciousness in the olfactory system before using the newly introduced system to provide evidence that attention is necessary for consciousness.

  4. The role of somatic threat feature detectors in the attentional bias toward pain: effects of spatial attention.

    Science.gov (United States)

    Dowman, Robert

    2011-03-01

    Our previous work suggests that somatic threat feature detectors indexed by a pain-evoked midlatency negative scalp potential play an important role in the attentional bias toward pain. In these studies the somatic threat feature detectors facilitated the shift in attention to a somatic threat when attention was focused on another stimulus modality but not when it was focused on another spatial location. This experiment used the Posner cuing paradigm to investigate possible explanations for this discrepancy. The results demonstrate that the different somatic threat effects observed in previous modal and spatial cuing studies are not due to attentional set. Rather, this discrepancy may be related to differences in contingent attention capture. This study also verifies earlier findings suggesting that some of the pain-related P2 component generators are involved in stimulus-driven shifts in spatial attention toward task-relevant stimuli.

  5. Formalin evokes calcium transients from the endoplasmatic reticulum.

    Directory of Open Access Journals (Sweden)

    Michael J M Fischer

    Full Text Available The formalin test is the most widely used behavioral screening test for analgesic compounds. The cellular mechanism of action of formaldehyde, inducing a typically biphasic pain-related behavior in rodents is addressed in this study. The chemoreceptor channel TRPA1 was suggested as primary transducer, but the high concentrations used in the formalin test elicit a similar response in TRPA1 wildtype and knockout animals. Here we show that formaldehyde evokes a dose-dependent calcium release from intracellular stores in mouse sensory neurons and primary keratinocytes as well as in non-neuronal cell lines, and independent of TRPA1. The source of calcium is the endoplasmatic reticulum and inhibition of the sarco/endoplasmic reticulum calcium-ATPase has a major contribution. This TRPA1-independent mechanism may underlie formaldehyde-induced pan-neuronal excitation and subsequent inflammation.

  6. Attenuated contact heat-evoked potentials associated with sensory and social-emotional symptoms in individuals with autism spectrum disorder

    Science.gov (United States)

    Chien, Yi-Ling; Wu, Shao-Wei; Chu, Chih-Pang; Hsieh, Sung-Tsang; Chao, Chi-Chao; Gau, Susan Shur-Fen

    2017-01-01

    Sensory disturbance is associated with socio-emotional problems in individuals with autism spectrum disorder (ASD). Most studies assess sensory symptoms by self-reports, which are largely limited by the language ability and self-awareness of the individuals. This study aims to investigate sensory disturbance by contact heat-evoked potentials (CHEP) in ASD individuals, and to examine the clinical correlates of CHEP parameters. We compared the CHEP parameters and reported pain between 31 ASD individuals (aged 20.5 ± 5.2 years) and and 22 typically-developing controls (TD, aged 21.4 ± 2.6), and correlated the CHEP parameters with self-reported sensory symptoms and attention/socio-emotional symptoms. We found that ASD individuals showed smaller P2-wave amplitudes than TD, even though they reported a similar level of pain. In TD individuals, a smaller P2-wave amplitude was related to higher scores on ‘low registration,’ ‘attention to detail,’ and ‘attention switching difficulties.’ In ASD individuals, longer N2-wave latency was related to higher scores on ‘sensory sensitivity’ and socio-emotional problems; while higher reported pain was associated with higher scores on ‘low registration,’ overall autistic severity, and longer N2-wave latency. Our findings of attenuated CHEP response in ASD, which was associated with sensory symptoms and socio-emotional problems, suggest a potential role for CHEP in studying sensory disturbances in ASD. PMID:28139664

  7. Visual attentional load influences plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Hall, Michelle G; Lye, Hayley F; Sale, Martin V; Fenlon, Laura R; Carroll, Timothy J; Riek, Stephan; Mattingley, Jason B

    2012-05-16

    Neural plasticity plays a critical role in learning, memory, and recovery from injury to the nervous system. Although much is known about the physical and physiological determinants of plasticity, little is known about the influence of cognitive factors. In this study, we investigated whether selective attention plays a role in modifying changes in neural excitability reflecting long-term potentiation (LTP)-like plasticity. We induced LTP-like effects in the hand area of the human motor cortex using transcranial magnetic stimulation (TMS). During the induction of plasticity, participants engaged in a visual detection task with either low or high attentional demands. Changes in neural excitability were assessed by measuring motor-evoked potentials in a small hand muscle before and after the TMS procedures. In separate experiments plasticity was induced either by paired associative stimulation (PAS) or intermittent theta-burst stimulation (iTBS). Because these procedures induce different forms of LTP-like effects, they allowed us to investigate the generality of any attentional influence on plasticity. In both experiments reliable changes in motor cortex excitability were evident under low-load conditions, but this effect was eliminated under high-attentional load. In a third experiment we investigated whether the attentional task was associated with ongoing changes in the excitability of motor cortex, but found no difference in evoked potentials across the levels of attentional load. Our findings indicate that in addition to their role in modifying sensory processing, mechanisms of attention can also be a potent modulator of cortical plasticity.

  8. Light-evoked S-nitrosylation in the retina.

    Science.gov (United States)

    Tooker, Ryan E; Vigh, Jozsef

    2015-10-01

    Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to modulate visual signal processing at multiple sites in the vertebrate retina, via activation of the most sensitive target of NO signaling, soluble guanylate cyclase. NO can also alter protein structure and function and exert biological effects directly by binding to free thiol groups of cysteine residues in a chemical reaction called S-nitrosylation. However, in the central nervous system, including the retina, this reaction has not been considered to be significant under physiological conditions. Here we provide immunohistochemical evidence for extensive S-nitrosylation that takes place in the goldfish and mouse retinas under physiologically relevant light intensities, in an intensity-dependent manner, with a strikingly similar pattern in both species. Pretreatment with N-ethylmaleimide (NEM), which occludes S-nitrosylation, or with 1-(2-trifluromethylphenyl)imidazole (TRIM), an inhibitor of neuronal NO synthase, eliminated the light-evoked increase in S-nitrosylated protein immunofluorescence (SNI) in the retinas of both species. Similarly, light did not increase SNI, above basal levels, in retinas of transgenic mice lacking neuronal NO synthase. Qualitative analysis of the light-adapted mouse retina with mass spectrometry revealed more than 300 proteins that were S-nitrosylated upon illumination, many of which are known to participate directly in retinal signal processing. Our data strongly suggest that in the retina light-evoked NO production leads to extensive S-nitrosylation and that this process is a significant posttranslational modification affecting a wide range of proteins under physiological conditions.

  9. Attention Modulates TMS-Locked Alpha Oscillations in the Visual Cortex.

    Science.gov (United States)

    Herring, Jim D; Thut, Gregor; Jensen, Ole; Bergmann, Til O

    2015-10-28

    Cortical oscillations, such as 8-12 Hz alpha-band activity, are thought to subserve gating of information processing in the human brain. While most of the supporting evidence is correlational, causal evidence comes from attempts to externally drive ("entrain") these oscillations by transcranial magnetic stimulation (TMS). Indeed, the frequency profile of TMS-evoked potentials (TEPs) closely resembles that of oscillations spontaneously emerging in the same brain region. However, it is unclear whether TMS-locked and spontaneous oscillations are produced by the same neuronal mechanisms. If so, they should react in a similar manner to top-down modulation by endogenous attention. To test this prediction, we assessed the alpha-like EEG response to TMS of the visual cortex during periods of high and low visual attention while participants attended to either the visual or auditory modality in a cross-modal attention task. We observed a TMS-locked local oscillatory alpha response lasting several cycles after TMS (but not after sham stimulation). Importantly, TMS-locked alpha power was suppressed during deployment of visual relative to auditory attention, mirroring spontaneous alpha amplitudes. In addition, the early N40 TEP component, located at the stimulation site, was amplified by visual attention. The extent of attentional modulation for both TMS-locked alpha power and N40 amplitude did depend, with opposite sign, on the individual ability to modulate spontaneous alpha power at the stimulation site. We therefore argue that TMS-locked and spontaneous oscillations are of common neurophysiological origin, whereas the N40 TEP component may serve as an index of current cortical excitability at the time of stimulation.

  10. Teaching and Learning Physics: Performance Art Evoking Insight

    Science.gov (United States)

    Sommer, Wilfried

    2015-01-01

    Doing experiments in physics lessons can create a magical moment if students become really intrigued with the experimental progression. They add a new quality to what the experiment shows. Their attention and nature's revelations flow together: a performance is taking place. It's similar to a moment during a theatrical performance, when the…

  11. Do ambient urban odors evoke basic emotions?

    Directory of Open Access Journals (Sweden)

    Sandra Theresia Weber-Glass

    2014-04-01

    Full Text Available Fragrances, such as plant odors, have been shown to evoke autonomic response patterns associated with Ekman’s (Ekman et al., 1983 basic emotions happiness, surprise, anger, fear, sadness and disgust. Inducing positive emotions by odors in highly frequented public spaces could serve to improve the quality of life in urban environments. Thus, the present study evaluated the potency of ambient odors connoted with an urban environment to evoke basic emotions on an autonomic and cognitive response level. Synthetic mixtures representing the odors of disinfectant, candles / bees wax, summer air, burnt smell, vomit and musty smell as well as odorless water as a control were presented five times in random order to 30 healthy, non-smoking human subjects with intact sense of smell. Skin temperature, skin conductance, breathing rate, forearm muscle activity, blink rate and heart rate were recorded simultaneously. Subjects rated the odors in terms of pleasantness, intensity and familiarity and gave verbal labels to each odor as well as cognitive associations with the basic emotions. The results showed that the amplitude of the skin conductance response varied as a function of odor presentation. Burnt smell and vomit elicited significantly higher electrodermal responses than summer air. Also, a negative correlation was revealed between the amplitude of the skin conductance response and hedonic odor valence indicating that the magnitude of the electrodermal response increased with odor unpleasantness. The analysis of the cognitive associations between odors and basic emotions showed that candles / bees wax and summer air were specifically associated with happiness whereas burnt smell and vomit were uniquely associated with disgust. Our findings suggest that city odors may evoke specific cognitive associations of basic emotions and that autonomic activity elicited by such odors is related to odor hedonics.

  12. Do ambient urban odors evoke basic emotions?

    Science.gov (United States)

    Glass, Sandra T; Lingg, Elisabeth; Heuberger, Eva

    2014-01-01

    Fragrances, such as plant odors, have been shown to evoke autonomic response patterns associated with Ekman's (Ekman et al., 1983) basic emotions happiness, surprise, anger, fear, sadness, and disgust. Inducing positive emotions by odors in highly frequented public spaces could serve to improve the quality of life in urban environments. Thus, the present study evaluated the potency of ambient odors connoted with an urban environment to evoke basic emotions on an autonomic and cognitive response level. Synthetic mixtures representing the odors of disinfectant, candles/bees wax, summer air, burnt smell, vomit and musty smell as well as odorless water as a control were presented five times in random order to 30 healthy, non-smoking human subjects with intact sense of smell. Skin temperature, skin conductance, breathing rate, forearm muscle activity, blink rate, and heart rate were recorded simultaneously. Subjects rated the odors in terms of pleasantness, intensity and familiarity and gave verbal labels to each odor as well as cognitive associations with the basic emotions. The results showed that the amplitude of the skin conductance response (SCR) varied as a function of odor presentation. Burnt smell and vomit elicited significantly higher electrodermal responses than summer air. Also, a negative correlation was revealed between the amplitude of the SCR and hedonic odor valence indicating that the magnitude of the electrodermal response increased with odor unpleasantness. The analysis of the cognitive associations between odors and basic emotions showed that candles/bees wax and summer air were specifically associated with happiness whereas burnt smell and vomit were uniquely associated with disgust. Our findings suggest that city odors may evoke specific cognitive associations of basic emotions and that autonomic activity elicited by such odors is related to odor hedonics.

  13. GABAA receptors modulate cannabinoid-evoked hypothermia.

    Science.gov (United States)

    Rawls, S M; Tallarida, R J; Kon, D A; Geller, E B; Adler, Martin W

    2004-05-01

    Cannabinoids evoke hypothermia by stimulating central CB(1) receptors. GABA induces hypothermia via GABA(A) or GABA(B) receptor activation. CB(1) receptor activation increases GABA release in the hypothalamus, a central locus for thermoregulation, suggesting that cannabinoid and GABA systems may be functionally linked in body temperature regulation. We investigated whether GABA receptors modulate the hypothermic actions of [4,5-dihydro-2-methyl-4(4-morpholinylmethyl)-1-(1-naphthalenyl-carbonyl)-6H-pyrrolo[3,2,1ij]quinolin-6-one] (WIN 55212-2), a selective cannabinoid agonist, in male Sprague-Dawley rats. WIN 55212-2 (2.5 mg/kg im) produced a rapid hypothermia that peaked 45-90 min postinjection. The hypothermia was attenuated by bicuculline (2 mg/kg ip), a GABA(A) antagonist. However, SCH 50911 (1-10 mg/kg ip), a GABA(B) blocker, did not antagonize the hypothermia. Neither bicuculline (2 mg/kg) nor SCH 50911 (10 mg/kg) by itself altered body temperature. We also investigated a possible role for CB(1) receptors in GABA-generated hypothermia. Muscimol (2.5 mg/kg ip), a GABA(A) agonist, or baclofen (5 mg/kg ip), a GABA(B) agonist, evoked a significant hypothermia. Blockade of CB(1) receptors with SR141716A (2.5 mg/kg im) did not antagonize muscimol- or baclofen-induced hypothermia, indicating that GABA-evoked hypothermia does not contain a CB(1)-sensitive component. Our results implicate GABA(A) receptors in the hypothermic actions of cannabinoids and provide further evidence of a functional link between cannabinoid and GABA systems.

  14. Somatosensory evoked response: application in neurology

    Directory of Open Access Journals (Sweden)

    Carlos A. M. Guerreiro

    1982-03-01

    Full Text Available One technique used for short-latency somatosensory evoked response (SER is described. SER following nerve stimulation is a unique non-invasive, clinical test used to evaluate the somatosensory pathways. It tests the physiological function of the median nerve, the brachial plexus, the C6-7 cervical roots, cervical spinal cord, the cuneate nuclei, the medial lemniscus, the thalamus, and the contralateral sensory cortex. It has been shown to be a reliable and useful clinical test partiicularly in multiple sclerosis and comatose patients. The promising technique of SER following peroneal nerve stimulation is mentioned.

  15. Task-evoked pupillometry provides a window into the development of short-term memory capacity

    Directory of Open Access Journals (Sweden)

    Elizabeth L. Johnson

    2014-03-01

    Full Text Available The capacity to keep multiple items in short-term memory (STM improves over childhood and provides the foundation for the development of multiple cognitive abilities. The goal of this study was to measure the extent to which age differences in STM capacity are related to differences in task engagement during encoding. Children (n = 69, mean age = 10.5 years and adults (n = 54, mean age = 27.5 years performed two STM tasks: the forward digit span test from the Wechsler Intelligence Scale for Children (WISC and a novel eyetracking digit span task designed to overload STM capacity. Building on prior research showing that task-evoked pupil dilation can be used as a real-time index of task engagement, we measured changes in pupil dilation while participants encoded long sequences of digits for subsequent recall. As expected, adults outperformed children on both STM tasks. We found similar patterns of pupil dilation while children and adults listened to the first six digits on our STM Overload task, after which the adults’ pupils continued to dilate and the children’s began to constrict, suggesting that the children had reached their cognitive limits and that they had begun to disengage attention from the task. Indeed, the point at which pupil dilation peaked at encoding was a significant predictor of WISC forward span, and this relationship held even after partialing out recall performance on the STM Overload task. These findings indicate that sustained task engagement at encoding is an important component of the development of STM.

  16. Attention Mosaics: Studies of Organizational Attention

    OpenAIRE

    Carvalho de Mesquita Ferreira, Luciana

    2010-01-01

    textabstractOrganizational studies emphasizing the role of attention in organizational behavior depart from the idea that organizations, like individuals, have limited capacity to attend to environmental stimuli. The bounded capacity of the organizations to respond to stimuli is conditioned by the limited cognitions of individuals and by the limited capability of organizations to distribute, coordinate and integrate those cognitions. The cross-level nature of organizational attention, its dua...

  17. [Emotional self-regulation in infantile attention deficit hyperactivity disorder and P300 evoked potentials].

    Science.gov (United States)

    Roca, Patricia; Mulas, Fernando; Ortiz-Sánchez, Pedro; Gandía-Benetó, Rubén

    2015-02-25

    Introduccion. Las dificultades de regulacion emocional en los pacientes con trastorno por deficit de atencion/hiperactividad (TDAH) han despertado un interes marcado en los ultimos años, y existe una linea de trabajo en la identificacion de correlatos neurofisiologicos. Objetivo. Analizar, en una muestra de niños con TDAH con y sin tratamiento, medidas de funcionamiento emocional y su correlacion con el componente P300. Pacientes y metodos. La muestra constaba de 71 niños con TDAH, de los que casi la mitad tomaba medicacion. Se analizo el potencial P300 auditivo. Los padres cumplimentaron una escala de comportamiento ejecutivo en el hogar –Behavior Rating Inventory of Executive Function (BRIEF)–, de la que se tomo el indice de autorregulacion emocional, y la escala de expresion emocional. Resultados. Se hallaron correlaciones significativas entre la amplitud del P300 y el indice de autorregulacion emocional de la version para preescolares del BRIEF, y se encontro relacion entre la latencia del P300 y la gravedad de los sintomas. Conclusion. Los resultados enfatizan la utilidad de los potenciales evocados para el estudio de correlatos ejecutivos y condiciones asociadas en el funcionamiento diario de los niños con TDAH.

  18. Peripheral nerve injury increases glutamate-evoked calcium mobilization in adult spinal cord neurons

    Directory of Open Access Journals (Sweden)

    Doolen Suzanne

    2012-07-01

    Full Text Available Abstract Background Central sensitization in the spinal cord requires glutamate receptor activation and intracellular Ca2+ mobilization. We used Fura-2 AM bulk loading of mouse slices together with wide-field Ca2+ imaging to measure glutamate-evoked increases in extracellular Ca2+ to test the hypotheses that: 1. Exogenous application of glutamate causes Ca2+ mobilization in a preponderance of dorsal horn neurons within spinal cord slices taken from adult mice; 2. Glutamate-evoked Ca2+ mobilization is associated with spontaneous and/or evoked action potentials; 3. Glutamate acts at glutamate receptor subtypes to evoked Ca2+ transients; and 4. The magnitude of glutamate-evoked Ca2+ responses increases in the setting of peripheral neuropathic pain. Results Bath-applied glutamate robustly increased [Ca2+]i in 14.4 ± 2.6 cells per dorsal horn within a 440 x 330 um field-of-view, with an average time-to-peak of 27 s and decay of 112 s. Repeated application produced sequential responses of similar magnitude, indicating the absence of sensitization, desensitization or tachyphylaxis. Ca2+ transients were glutamate concentration-dependent with a Kd = 0.64 mM. Ca2+ responses predominantly occurred on neurons since: 1 Over 95% of glutamate-responsive cells did not label with the astrocyte marker, SR-101; 2 62% of fura-2 AM loaded cells exhibited spontaneous action potentials; 3 75% of cells that responded to locally-applied glutamate with a rise in [Ca2+]i also showed a significant increase in AP frequency upon a subsequent glutamate exposure; 4 In experiments using simultaneous on-cell recordings and Ca2+ imaging, glutamate elicited a Ca2+ response and an increase in AP frequency. AMPA/kainate (CNQX- and AMPA (GYKI 52466-selective receptor antagonists significantly attenuated glutamate-evoked increases in [Ca2+]i, while NMDA (AP-5, kainate (UBP-301 and class I mGluRs (AIDA did not. Compared to sham controls, peripheral nerve injury

  19. Similarity transformations of MAPs

    Directory of Open Access Journals (Sweden)

    Andersen Allan T.

    1999-01-01

    Full Text Available We introduce the notion of similar Markovian Arrival Processes (MAPs and show that the event stationary point processes related to two similar MAPs are stochastically equivalent. This holds true for the time stationary point processes too. We show that several well known stochastical equivalences as e.g. that between the H 2 renewal process and the Interrupted Poisson Process (IPP can be expressed by the similarity transformations of MAPs. In the appendix the valid region of similarity transformations for two-state MAPs is characterized.

  20. SOMATOSENSORY EVOKED POTENTIALS IN DIABETES MELLITUS TYPE - 2

    Directory of Open Access Journals (Sweden)

    Rekha

    2015-10-01

    Full Text Available Diabetes mellitus is the most common metabolic disorder affecting majority of population. It is estimated that over 400 million people throughout the world have diabetes. It has progressed to be a pandemic from an epidemic causing morbidity and mortality in the population. Among the many complications of diabetes, diabetic neuropathies contribute majorly to the morbidity associated with the disease. Axonal conduction is affected by elevated levels of protein kinase c causing neuronal ischemia; decreased ce llular myoinositol affecting sodium potassium ATPase pump leads to decreased nerve conduction; Somatosensory E voked P otentials (SSEPs reflect the activity of somatosensory pathways mediated through the dorsal columns of the spinal cord and the specific so matosensory cortex. Recording of Somatosensory Evoked Potentials in diabetics is done to assess the sensory involvement of spinal cord. Presence of SEPs provides clear evidence for axonal continuity and by using different stimulation sites, the rate of reg eneration can be determined. Both onset and peak latencies of all SEP components are prolonged in patients with diabetes. Present study is done to compare somatosensory evoked potentials in diabetics and normal subjects. MATERIALS AND METHOD S: The present study was undertaken at the Upgraded Department of Physiology, Osmania Medical College, Koti, Hyderabad. The study was conducted on subjects, both male and female in the age group of 45 to 55 years, suffering from type II diabetes excluding other neurologi cal disorders. Non - invasive method of estimation of nerve conduction studies using SFEMG/EP — Electromyography or evoked potential system (Nicolet systems — USA using surface electrodes with automated computerized monitor attached with printer is used. RESUL TS : ANOVA showed statistically significant N9 latency (right & left sides. Latencies of all the components of SSEPs were more significant than amplitudes in Diabetic

  1. Attention Breaks in Lectures

    Science.gov (United States)

    Johnstone, A. H.; Percival, F.

    1976-01-01

    Describes research into student attention patterns during lectures that suggests that student attention declines steadily during a lecture, and that the rate of decrease is dependent upon several variables including subject difficulty. (MLH)

  2. Understanding Attention Deficit Disorders.

    Science.gov (United States)

    Villegas, Orlando; And Others

    This booklet provides basic information regarding attention deficit hyperactivity disorders (ADHD), in their separate modalities, with hyperactivity, impulsivity, and inattention. Explanations are offered concerning short attention span, impulsive behavior, hyperactivity, and beginning new activities before completing the previous one. Theories…

  3. Developmental attentional dyslexia.

    Science.gov (United States)

    Friedmann, Naama; Kerbel, Noa; Shvimer, Lilach

    2010-01-01

    Attentional dyslexia is a reading deficit in which letters migrate between neighboring words, but are correctly identified and keep their correct relative position within the word. Thus, for example, fig tree can be read as fig free or even tie free. This study reports on 10 Hebrew-speaking individuals with developmental attentional dyslexia and explores in detail the characteristics of their between-word errors. Each participant read 2290 words, presented in word pairs: 845 horizontally presented word pairs, 240 vertically presented word pairs, and 60 nonword pairs. The main results are that almost all migrations preserve the relative position of the migrating letter within the word, indicating that the between-word position can be impaired while the within-word position encoding remains intact. This result is also supported by the finding that the participants did not make many letter position errors within words. Further analyses indicated that more errors occur in longer words, that most migrations occur in final letters (which are the leftmost letters in Hebrew), and that letters migrate both horizontally and vertically, and more frequently from the first to the second word in horizontal presentation. More migrations occurred when the result of migration was an existing word. Similarity between words in a pair did not increase error rates, and more migrations occurred when the words shared fewer letters. The between-word errors included the classic errors of migration of a letter between words, but also omission of one instance of a letter that appeared in the same position in the two words, an error that constituted a considerable percentage of the between-word errors, and intrusion of a letter from one word to the corresponding position in the neighboring word without erasing the original letter in the same position.

  4. Speech Evoked Auditory Brainstem Response in Stuttering

    Directory of Open Access Journals (Sweden)

    Ali Akbar Tahaei

    2014-01-01

    Full Text Available Auditory processing deficits have been hypothesized as an underlying mechanism for stuttering. Previous studies have demonstrated abnormal responses in subjects with persistent developmental stuttering (PDS at the higher level of the central auditory system using speech stimuli. Recently, the potential usefulness of speech evoked auditory brainstem responses in central auditory processing disorders has been emphasized. The current study used the speech evoked ABR to investigate the hypothesis that subjects with PDS have specific auditory perceptual dysfunction. Objectives. To determine whether brainstem responses to speech stimuli differ between PDS subjects and normal fluent speakers. Methods. Twenty-five subjects with PDS participated in this study. The speech-ABRs were elicited by the 5-formant synthesized syllable/da/, with duration of 40 ms. Results. There were significant group differences for the onset and offset transient peaks. Subjects with PDS had longer latencies for the onset and offset peaks relative to the control group. Conclusions. Subjects with PDS showed a deficient neural timing in the early stages of the auditory pathway consistent with temporal processing deficits and their abnormal timing may underlie to their disfluency.

  5. Interaural difference values of vestibular evoked myogenic.

    Directory of Open Access Journals (Sweden)

    Marziyeh Moallemi

    2015-01-01

    Full Text Available Migraine is a neurologic disease, which often is associated with a unilateral headache. Vestibular abnormalities are common in migraine. Vestibular evoked myogenic potentials (VEMPs assess otolith function in particular functional integrity of the saccule and the inferior vestibular nerve. We used VEMP to evaluate if the migraine headache can affect VEMP asymmetry parameters. A total of 25 patients with migraine (22 females and 3 males who were diagnosed according to the criteria of IHS-1988 were enrolled in this cross-sectional study. Control group consisted of 26 healthy participants (18 female and 8 male, without neurotological symptoms and history of migraine. The short tone burst (95 dB nHL, 500 Hz was presented to ears. VEMP was recorded with surface electromyography over the contracted ipsilateral sternocleidomastoid (SCM muscle. Although current results showed that the amplitude ratio is greater in migraine patients than normal group, there was no statistical difference between two groups in mean asymmetry parameters of VEMP. Asymmetry measurements in vestibular evoked myogenic potentials probably are not indicators of unilateral deficient in saccular pathways of migraine patients.

  6. Auditory evoked potentials in postconcussive syndrome.

    Science.gov (United States)

    Drake, M E; Weate, S J; Newell, S A

    1996-12-01

    The neuropsychiatric sequelae of minor head trauma have been the source of controversy. Most clinical and imaging studies have shown no alteration after concussion, but neuropsychological and neuropathological abnormalities have been reported. Some changes in neurophysiologic diagnostic tests have been described in postconcussive syndrome. We recorded middle latency auditory evoked potentials (MLR) and slow vertex responses (SVR) in 20 individuals with prolonged cognitive difficulties, behavior changes, dizziness, and headache after concussion. MLR is utilized alternating polarity clicks presented monaurally at 70 dB SL at 4 per second, with 40 dB contralateral masking. Five hundred responses were recorded and replicated from Cz-A1 and Cz-A2, with 50 ms. analysis time and 20-1000 Hz filter band pass. SVRs were recorded with the same montage, but used rarefaction clicks, 0.5 Hz stimulus rate, 500 ms. analysis time, and 1-50 Hz filter band pass. Na and Pa MLR components were reduced in amplitude in postconcussion patients. Pa latency was significantly longer in patients than in controls. SVR amplitudes were longer in concussed individuals, but differences in latency and amplitude were not significant. These changes may reflect posttraumatic disturbance in presumed subcortical MLR generators, or in frontal or temporal cortical structures that modulate them. Middle and long-latency auditory evoked potentials may be helpful in the evaluation of postconcussive neuropsychiatric symptoms.

  7. Evoked potentials in pediatric cerebral malaria

    Directory of Open Access Journals (Sweden)

    Minal Bhanushali

    2011-12-01

    Full Text Available Cortical evoked potentials (EP provide localized data regarding brain function and may offer prognostic information and insights into the pathologic mechanisms of malariamediated cerebral injury. As part of a prospective cohort study, we obtained somatosensory evoked potentials (SSEPs and brainstem auditory EPs (AEPs within 24 hours of admission on 27 consecutive children admitted with cerebral malaria (CM. Children underwent follow-up for 12 months to determine if they had any long term neurologic sequelae. EPs were obtained in 27 pediatric CM admissions. Two children died. Among survivors followed an average of 514 days, 7/25 (28.0% had at least one adverse neurologic outcome. Only a single subject had absent cortical EPs on admission and this child had a good neurologic outcome. Among pediatric CM survivors, cortical EPs are generally intact and do not predict adverse neurologic outcomes. Further study is needed to determine if alterations in cortical EPs can be used to predict a fatal outcome in CM.

  8. Long Latency Auditory Evoked Potentials during Meditation.

    Science.gov (United States)

    Telles, Shirley; Deepeshwar, Singh; Naveen, Kalkuni Visweswaraiah; Pailoor, Subramanya

    2015-10-01

    The auditory sensory pathway has been studied in meditators, using midlatency and short latency auditory evoked potentials. The present study evaluated long latency auditory evoked potentials (LLAEPs) during meditation. Sixty male participants, aged between 18 and 31 years (group mean±SD, 20.5±3.8 years), were assessed in 4 mental states based on descriptions in the traditional texts. They were (a) random thinking, (b) nonmeditative focusing, (c) meditative focusing, and (d) meditation. The order of the sessions was randomly assigned. The LLAEP components studied were P1 (40-60 ms), N1 (75-115 ms), P2 (120-180 ms), and N2 (180-280 ms). For each component, the peak amplitude and peak latency were measured from the prestimulus baseline. There was significant decrease in the peak latency of the P2 component during and after meditation (Pmeditation facilitates the processing of information in the auditory association cortex, whereas the number of neurons recruited was smaller in random thinking and non-meditative focused thinking, at the level of the secondary auditory cortex, auditory association cortex and anterior cingulate cortex.

  9. The effectiveness of FES-evoked EMG potentials to assess muscle force and fatigue in individuals with spinal cord injury.

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Estigoni, Eduardo H; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M

    2014-07-14

    The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p SCI) population.

  10. External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1.

    Science.gov (United States)

    Hofmann, Mackenzie E; Largent-Milnes, Tally M; Fawley, Jessica A; Andresen, Michael C

    2014-12-01

    The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 μM QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1- ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1- inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents.

  11. Attention Competition with Advertisement

    OpenAIRE

    Cetin, Uzay; Bingol, Haluk O.

    2012-01-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when a...

  12. Mindfulness training affects attention--or is it attentional effort?

    Science.gov (United States)

    Jensen, Christian Gaden; Vangkilde, Signe; Frokjaer, Vibe; Hasselbalch, Steen G

    2012-02-01

    Improvements in attentional performance are at the core of proposed mechanisms for stress reduction in mindfulness meditation practices. However, this claim can be questioned because no previous studies have actively manipulated test effort in control groups and controlled for effects of stress reduction per se. In a blinded design, 48 young, healthy meditation novices were randomly assigned to a mindfulness-based stress reduction (MBSR), nonmindfulness stress reduction (NMSR), or inactive control group. At posttest, inactive controls were randomly split into nonincentive and incentive controls, the latter receiving a financial reward to improve attentional performance. Pre- and postintervention, 5 validated attention paradigms were employed along with self-report scales on mindfulness and perceived stress and saliva cortisol samples to measure physiological stress. Attentional effects of MBSR, NMSR, and the financial incentive were comparable or significantly larger in the incentive group on all reaction-time-based measures. However, selective attention in the MBSR group improved significantly more than in any other group. Similarly, only the MBSR intervention improved the threshold for conscious perception and visual working memory capacity. Furthermore, stress-reducing effects of MBSR were supported because those in the MBSR group showed significantly less perceived and physiological stress while increasing their mindfulness levels significantly. We argue that MBSR may contribute uniquely to attentional improvements but that further research focusing on non-reaction-time-based measures and outcomes less confounded by test effort is needed. Critically, our data demonstrate that previously observed improvements of attention after MBSR may be seriously confounded by test effort and nonmindfulness stress reduction.

  13. Attentional Processes in Autism.

    Science.gov (United States)

    Goldstein, Gerald; Johnson, Cynthia R.; Minshew, Nancy J.

    2001-01-01

    Attention processes in 103 children and adults with high functioning autism were compared with a matched control group using a battery of attention measures. Differences were found only on tasks which placed demands on cognitive flexibility or psychomotor speed, suggesting that purported attention deficits in autism may actually be primary…

  14. New Similarity Functions

    DEFF Research Database (Denmark)

    Yazdani, Hossein; Ortiz-Arroyo, Daniel; Kwasnicka, Halina

    2016-01-01

    In data science, there are important parameters that affect the accuracy of the algorithms used. Some of these parameters are: the type of data objects, the membership assignments, and distance or similarity functions. This paper discusses similarity functions as fundamental elements in membership...

  15. Clustering by Pattern Similarity

    Institute of Scientific and Technical Information of China (English)

    Hai-xun Wang; Jian Pei

    2008-01-01

    The task of clustering is to identify classes of similar objects among a set of objects. The definition of similarity varies from one clustering model to another. However, in most of these models the concept of similarity is often based on such metrics as Manhattan distance, Euclidean distance or other Lp distances. In other words, similar objects must have close values in at least a set of dimensions. In this paper, we explore a more general type of similarity. Under the pCluster model we proposed, two objects are similar if they exhibit a coherent pattern on a subset of dimensions. The new similarity concept models a wide range of applications. For instance, in DNA microarray analysis, the expression levels of two genes may rise and fall synchronously in response to a set of environmental stimuli. Although the magnitude of their expression levels may not be close, the patterns they exhibit can be very much alike. Discovery of such clusters of genes is essential in revealing significant connections in gene regulatory networks. E-commerce applications, such as collaborative filtering, can also benefit from the new model, because it is able to capture not only the closeness of values of certain leading indicators but also the closeness of (purchasing, browsing, etc.) patterns exhibited by the customers. In addition to the novel similarity model, this paper also introduces an effective and efficient algorithm to detect such clusters, and we perform tests on several real and synthetic data sets to show its performance.

  16. Judgments of brand similarity

    NARCIS (Netherlands)

    Bijmolt, THA; Wedel, M; Pieters, RGM; DeSarbo, WS

    1998-01-01

    This paper provides empirical insight into the way consumers make pairwise similarity judgments between brands, and how familiarity with the brands, serial position of the pair in a sequence, and the presentation format affect these judgments. Within the similarity judgment process both the formatio

  17. The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

    Science.gov (United States)

    Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

    2015-01-01

    Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference.

  18. New Similarity Functions

    DEFF Research Database (Denmark)

    Yazdani, Hossein; Ortiz-Arroyo, Daniel; Kwasnicka, Halina

    2016-01-01

    In data science, there are important parameters that affect the accuracy of the algorithms used. Some of these parameters are: the type of data objects, the membership assignments, and distance or similarity functions. This paper discusses similarity functions as fundamental elements in membership...... assignments. The paper introduces Weighted Feature Distance (WFD), and Prioritized Weighted Feature Distance (PWFD), two new distance functions that take into account the diversity in feature spaces. WFD functions perform better in supervised and unsupervised methods by comparing data objects on their feature...... spaces, in addition to their similarity in the vector space. Prioritized Weighted Feature Distance (PWFD) works similarly as WFD, but provides the ability to give priorities to desirable features. The accuracy of the proposed functions are compared with other similarity functions on several data sets...

  19. Lidocaine alters the input resistance and evokes neural activity in crayfish sensory neurons.

    Science.gov (United States)

    Keceli, M B; Purali, N

    2007-03-01

    Lidocaine, a use-dependent Na(+) channel blocker, paradoxically evokes neural activation in the slowly adapting stretch receptor organ of crayfish at 5-10 mmol/l concentration. For elucidating the underlying mechanisms of this paradoxical effect, a series of conventional electrophysiological experiments were performed in the stretch receptor neurons of crayfish. In the presence of tetrodotoxin, lidocaine did not evoke impulse activity, however, a slowly developing and dose-dependent depolarization occurred in both the rapidly and slowly adapting stretch receptors. Similar effects were observed by perfusion of equivalent concentrations of benzocaine but not of procaine or prilocaine. Lidocaine did not evoke neural activity in the rapidly adapting neuron which fires action potential(s) in response to rapid changes in membrane potential. Slowly developing mode of the depolarization indicated the reason why only depolarization but not action potential responses were observed in the rapidly adapting neuron. The depolarizing effect of lidocaine was independent from any ionic channel or exchanger system. However, lidocaine and benzocaine but not procaine and prilocaine evoked a dose-dependent alteration in the input resistance of the neuron. It was proposed that the principal mechanism of the effect could stem from a change in the physical properties of the neuronal membrane.

  20. Diagnostic accuracy of evoked potentials for functional impairment after contusive spinal cord injury in adult rats.

    Science.gov (United States)

    Thirumala, Parthasarathy; Zhou, James; Krishnan, Rohan; Manem, Nihita; Umredkar, Shreya; Hamilton, D K; Balzer, Jeffrey R; Oudega, Martin

    2016-03-01

    Iatrogenic spinal cord injury (SCI) is a cause of potentially debilitating post-operative neurologic complications. Currently, intra-operative neurophysiological monitoring (IONM) via somatosensory evoked potentials and motor-evoked potentials is used to detect and prevent impending SCI. However, no empirically validated interventions exist to halt the progression of iatrogenic SCI once it is detected. This is in part due to the lack of a suitable translational model that mimics the circumstances surrounding iatrogenic SCI detected via IONM. Here, we evaluate a model of simulated contusive iatrogenic SCI detected via IONM in adult female Sprague-Dawley rats. We show that transient losses of somatosensory evoked potentials responses are 88.24% sensitive (95% confidence interval [CI] 63.53-98.20) and 80% specific (95% CI 51.91-95.43) for significant functional impairment following simulated iatrogenic SCI. Similarly, we show that transient losses in motor-evoked potentials responses are 70.83% sensitive (95% CI 48.91-87.33) and 100% specific (95% CI 62.91-100.00) for significant functional impairment following simulated iatrogenic SCI. These results indicate that our model is a suitable replica of the circumstances surrounding clinical iatrogenic SCI.

  1. Steady-state visual-evoked response to upright and inverted geometrical faces: a magnetoencephalography study.

    Science.gov (United States)

    Tsuruhara, Aki; Inui, Koji; Kakigi, Ryusuke

    2014-03-01

    The face is one of the most important visual stimuli in human life, and inverted faces are known to elicit different brain responses than upright faces. This study analyzed steady-state visual-evoked magnetic fields (SSVEFs) in eleven healthy participants when they viewed upright and inverted geometrical faces presented at 6Hz. Steady-state visual-evoked responses are useful measurements and have the advantages of robustness and a high signal-to-noise ratio. Spectrum analysis revealed clear responses to both upright and inverted faces at the fundamental stimulation frequency (6 Hz) and harmonics, i.e. SSVEFs. No significant difference was observed in the SSVEF amplitude at 6 Hz between upright and inverted faces, which was different from the transient visual-evoked response, N170. On the other hand, SSVEFs were delayed with the inverted face in the right temporal area, which was similar to N170 and the results of previous steady-state visual-evoked potentials studies. These results suggest that different mechanisms underlie the larger amplitude and delayed latency observed with face inversion, though further studies are needed to fully elucidate these mechanisms. Our study revealed that SSVEFs, which have practical advantages for measurements, could provide novel findings in human face processing.

  2. Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories.

    Science.gov (United States)

    Karns, Christina M; Isbell, Elif; Giuliano, Ryan J; Neville, Helen J

    2015-06-01

    Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) across five age groups: 3-5 years; 10 years; 13 years; 16 years; and young adults. Using a naturalistic dichotic listening paradigm, we characterized the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages.

  3. Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories

    Directory of Open Access Journals (Sweden)

    Christina M. Karns

    2015-06-01

    Full Text Available Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs across five age groups: 3–5 years; 10 years; 13 years; 16 years; and young adults. Using a naturalistic dichotic listening paradigm, we characterized the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages.

  4. Trajectories of CBCL Attention Problems in childhood

    NARCIS (Netherlands)

    S.C.C. Robbers (Sylvana); F.V.A. van Oort (Floor); T.J.C. Polderman (Tinca); M. Bartels (Meike); D.I. Boomsma (Dorret); F.C. Verhulst (Frank); G.H. Lubke (Gitta); A.C. Huizink (Anja)

    2011-01-01

    textabstractThe first aim of this study was to identify developmental trajectories of Attention Problems in twins followed from age 6 to 12 years. Second, we investigated whether singletons follow similar trajectories. Maternal longitudinal ratings on the Attention Problems (AP) subscale of the Chil

  5. Plant intelligence and attention.

    Science.gov (United States)

    Marder, Michael

    2013-05-01

    This article applies the phenomenological model of attention to plant monitoring of environmental stimuli and signal perception. Three complementary definitions of attention as selectivity, modulation and perdurance are explained with reference to plant signaling and behaviors, including foraging, ramet placement and abiotic stress communication. Elements of animal and human attentive attitudes are compared with plant attention at the levels of cognitive focus, context and margin. It is argued that the concept of attention holds the potential of becoming a cornerstone of plant intelligence studies.

  6. Attention competition with advertisement.

    Science.gov (United States)

    Cetin, Uzay; Bingol, Haluk O

    2014-09-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when the attention capacity of agents is extremely scarce. We have observed that the market share of the advertised item improves if dummy items are introduced to the market while the strength of the advertisement is kept constant.

  7. Attention competition with advertisement

    Science.gov (United States)

    Cetin, Uzay; Bingol, Haluk O.

    2014-09-01

    In the new digital age, information is available in large quantities. Since information consumes primarily the attention of its recipients, the scarcity of attention is becoming the main limiting factor. In this study, we investigate the impact of advertisement pressure on a cultural market where consumers have a limited attention capacity. A model of competition for attention is developed and investigated analytically and by simulation. Advertisement is found to be much more effective when the attention capacity of agents is extremely scarce. We have observed that the market share of the advertised item improves if dummy items are introduced to the market while the strength of the advertisement is kept constant.

  8. Similar component analysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; WANG Xin; LI Junwei; CAO Xianguang

    2006-01-01

    A new unsupervised feature extraction method called similar component analysis (SCA) is proposed in this paper. SCA method has a self-aggregation property that the data objects will move towards each other to form clusters through SCA theoretically,which can reveal the inherent pattern of similarity hidden in the dataset. The inputs of SCA are just the pairwise similarities of the dataset,which makes it easier for time series analysis due to the variable length of the time series. Our experimental results on many problems have verified the effectiveness of SCA on some engineering application.

  9. Attention Alters Perceived Attractiveness.

    Science.gov (United States)

    Störmer, Viola S; Alvarez, George A

    2016-04-01

    Can attention alter the impression of a face? Previous studies showed that attention modulates the appearance of lower-level visual features. For instance, attention can make a simple stimulus appear to have higher contrast than it actually does. We tested whether attention can also alter the perception of a higher-order property-namely, facial attractiveness. We asked participants to judge the relative attractiveness of two faces after summoning their attention to one of the faces using a briefly presented visual cue. Across trials, participants judged the attended face to be more attractive than the same face when it was unattended. This effect was not due to decision or response biases, but rather was due to changes in perceptual processing of the faces. These results show that attention alters perceived facial attractiveness, and broadly demonstrate that attention can influence higher-level perception and may affect people's initial impressions of one another.

  10. Principles of visual attention

    DEFF Research Database (Denmark)

    Bundesen, Claus; Habekost, Thomas

    The nature of attention is one of the oldest and most central problems in psychology. A huge amount of research has been produced on this subject in the last half century, especially on attention in the visual modality, but a general explanation has remained elusive. Many still view attention...... research as a field that is fundamentally fragmented. This book takes a different perspective and presents a unified theory of visual attention: the TVA model. The TVA model explains the many aspects of visual attention by just two mechanisms for selection of information: filtering and pigeonholing....... These mechanisms are described in a set of simple equations, which allow TVA to mathematically model a large number of classical results in the attention literature. The theory explains psychological and neuroscientific findings by the same equations; TVA is a complete theory of visual attention, linking mind...

  11. Gender similarities and differences.

    Science.gov (United States)

    Hyde, Janet Shibley

    2014-01-01

    Whether men and women are fundamentally different or similar has been debated for more than a century. This review summarizes major theories designed to explain gender differences: evolutionary theories, cognitive social learning theory, sociocultural theory, and expectancy-value theory. The gender similarities hypothesis raises the possibility of theorizing gender similarities. Statistical methods for the analysis of gender differences and similarities are reviewed, including effect sizes, meta-analysis, taxometric analysis, and equivalence testing. Then, relying mainly on evidence from meta-analyses, gender differences are reviewed in cognitive performance (e.g., math performance), personality and social behaviors (e.g., temperament, emotions, aggression, and leadership), and psychological well-being. The evidence on gender differences in variance is summarized. The final sections explore applications of intersectionality and directions for future research.

  12. Music evokes vicarious emotions in listeners.

    Science.gov (United States)

    Kawakami, Ai; Furukawa, Kiyoshi; Okanoya, Kazuo

    2014-01-01

    Why do we listen to sad music? We seek to answer this question using a psychological approach. It is possible to distinguish perceived emotions from those that are experienced. Therefore, we hypothesized that, although sad music is perceived as sad, listeners actually feel (experience) pleasant emotions concurrent with sadness. This hypothesis was supported, which led us to question whether sadness in the context of art is truly an unpleasant emotion. While experiencing sadness may be unpleasant, it may also be somewhat pleasant when experienced in the context of art, for example, when listening to sad music. We consider musically evoked emotion vicarious, as we are not threatened when we experience it, in the way that we can be during the course of experiencing emotion in daily life. When we listen to sad music, we experience vicarious sadness. In this review, we propose two sides to sadness by suggesting vicarious emotion.

  13. Resting Heart Rate and Auditory Evoked Potential

    Directory of Open Access Journals (Sweden)

    Simone Fiuza Regaçone

    2015-01-01

    Full Text Available The objective of this study was to evaluate the association between rest heart rate (HR and the components of the auditory evoked-related potentials (ERPs at rest in women. We investigated 21 healthy female university students between 18 and 24 years old. We performed complete audiological evaluation and measurement of heart rate for 10 minutes at rest (heart rate monitor Polar RS800CX and performed ERPs analysis (discrepancy in frequency and duration. There was a moderate negative correlation of the N1 and P3a with rest HR and a strong positive correlation of the P2 and N2 components with rest HR. Larger components of the ERP are associated with higher rest HR.

  14. Visual evoked potentials in rubber factory workers.

    Science.gov (United States)

    Tandon, O P; Kumar, V

    1997-01-01

    Pattern reversal visual evoked potentials (pVEP) were studied in 39 male rubber factory workers in the age range of 18-55 years and 20 control subjects (aged 18-46 years) not exposed to the rubber factory environment. Results revealed that 20 (51%) rubber factory workers had abnormal latencies of wave P1 (dominant component of pVEP) as per accepted criteria of 99% tolerance limit set for the control group (i.e. any value above mean +3 SD of control was considered abnormal). The section-wise per cent distribution of abnormalities was vulcanization (83%), tubing (75%), calendering (60%), loading (38%) and mixing (14%). This study provides electrophysiological evidence that rubber factory environments affect the conduction processes in optical pathways from their origin in the retina to striate cortex. However, this study has its limitations in not identifying the specific chemical(s) causing these changes in VEP.

  15. Bayesian analysis of MEG visual evoked responses

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, D.M.; George, J.S.; Wood, C.C.

    1999-04-01

    The authors developed a method for analyzing neural electromagnetic data that allows probabilistic inferences to be drawn about regions of activation. The method involves the generation of a large number of possible solutions which both fir the data and prior expectations about the nature of probable solutions made explicit by a Bayesian formalism. In addition, they have introduced a model for the current distributions that produce MEG and (EEG) data that allows extended regions of activity, and can easily incorporate prior information such as anatomical constraints from MRI. To evaluate the feasibility and utility of the Bayesian approach with actual data, they analyzed MEG data from a visual evoked response experiment. They compared Bayesian analyses of MEG responses to visual stimuli in the left and right visual fields, in order to examine the sensitivity of the method to detect known features of human visual cortex organization. They also examined the changing pattern of cortical activation as a function of time.

  16. RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS

    Directory of Open Access Journals (Sweden)

    A. A. Sazgar

    2006-05-01

    Full Text Available It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP for the first time in Iran. Eighteen healthy volunteers (32 ears without history of otologic or vestibular disorders were subjected to the VEMP test. Twenty-one patients (26 ears with unilateral (6 patients and bilateral (5 patients high frequency sensorineural hearing loss with unknown etiology, acoustic neuroma (1 patient, Meniere’s disease (4 patients and unilateral low frequency sensorineural hearing loss without vestibular complaint (5 patients were also enrolled in this study. VEMP response to clicks was obtained from 84.4% of ears of healthy subjects. These subjects demonstrated short latency waves to click stimuli during tonic neck flexor activation. Mean latencies of first positive (p13 and first negative (n23 potentials in healthy subjects were 12.45 ± 1.9 ms and 20.8 ± 3.5 ms, respectively. Median latencies of these two potentials were 12.1 and 19.3 ms, respectively. We could record VEMP in 5 patients with unilateral and all patients with high and low frequency sensorineural hearing loss without vestibular complaint. In the patient with acoustic neuroma VEMP was absent on the affected side. This technique may offer a new method to evaluate otolith and sacculocollic pathways in human.

  17. Attention Mosaics: Studies of Organizational Attention

    NARCIS (Netherlands)

    L. Carvalho de Mesquita Ferreira (Luciana)

    2010-01-01

    textabstractOrganizational studies emphasizing the role of attention in organizational behavior depart from the idea that organizations, like individuals, have limited capacity to attend to environmental stimuli. The bounded capacity of the organizations to respond to stimuli is conditioned by the l

  18. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  19. Internalization of the chemokine receptor CCR4 can be evoked by orthosteric and allosteric receptor antagonists.

    Science.gov (United States)

    Ajram, Laura; Begg, Malcolm; Slack, Robert; Cryan, Jenni; Hall, David; Hodgson, Simon; Ford, Alison; Barnes, Ashley; Swieboda, Dawid; Mousnier, Aurelie; Solari, Roberto

    2014-04-15

    The chemokine receptor CCR4 has at least two natural agonist ligands, MDC (CCL22) and TARC (CCL17) which bind to the same orthosteric site with a similar affinity. Both ligands are known to evoke chemotaxis of CCR4-bearing T cells and also elicit CCR4 receptor internalization. A series of small molecule allosteric antagonists have been described which displace the agonist ligand, and inhibit chemotaxis. The aim of this study was to determine which cellular coupling pathways are involved in internalization, and if antagonists binding to the CCR4 receptor could themselves evoke receptor internalization. CCL22 binding coupled CCR4 efficiently to β-arrestin and stimulated GTPγS binding however CCL17 did not couple to β-arrestin and only partially stimulated GTPγS binding. CCL22 potently induced internalization of almost all cell surface CCR4, while CCL17 showed only weak effects. We describe four small molecule antagonists that were demonstrated to bind to two distinct allosteric sites on the CCR4 receptor, and while both classes inhibited agonist ligand binding and chemotaxis, one of the allosteric sites also evoked receptor internalization. Furthermore, we also characterize an N-terminally truncated version of CCL22 which acts as a competitive antagonist at the orthosteric site, and surprisingly also evokes receptor internalization without demonstrating any agonist activity. Collectively this study demonstrates that orthosteric and allosteric antagonists of the CCR4 receptor are capable of evoking receptor internalization, providing a novel strategy for drug discovery against this class of target.

  20. Announcements to Attentive Agents

    DEFF Research Database (Denmark)

    Bolander, Thomas; van Ditmarsch, Hans; Herzig, Andreas;

    2016-01-01

    In public announcement logic it is assumed that all agents pay attention to the announcement. Weaker observational conditions can be modelled in action model logic. In this work, we propose a version of public announcement logic wherein it is encoded in the states of the epistemic model which...... agents pay attention to the announcement. This logic is called attention-based announcement logic. We give an axiomatization of the logic and prove that complexity of satisfiability is the same as that of public announcement logic, and therefore lower than that of action model logic. An attention......-based announcement can also be described as an action model. We extend our logic by integrating attention change. Finally, we add the notion of common belief to the language, we exploit this to formalize the concept of joint attention, that has been widely discussed in the philosophical and cognitive science...

  1. Compression-based Similarity

    CERN Document Server

    Vitanyi, Paul M B

    2011-01-01

    First we consider pair-wise distances for literal objects consisting of finite binary files. These files are taken to contain all of their meaning, like genomes or books. The distances are based on compression of the objects concerned, normalized, and can be viewed as similarity distances. Second, we consider pair-wise distances between names of objects, like "red" or "christianity." In this case the distances are based on searches of the Internet. Such a search can be performed by any search engine that returns aggregate page counts. We can extract a code length from the numbers returned, use the same formula as before, and derive a similarity or relative semantics between names for objects. The theory is based on Kolmogorov complexity. We test both similarities extensively experimentally.

  2. Chirp-modulated visual evoked potential as a generalization of steady state visual evoked potential

    Science.gov (United States)

    Tu, Tao; Xin, Yi; Gao, Xiaorong; Gao, Shangkai

    2012-02-01

    Visual evoked potentials (VEPs) are of great concern in cognitive and clinical neuroscience as well as in the recent research field of brain-computer interfaces (BCIs). In this study, a chirp-modulated stimulation was employed to serve as a novel type of visual stimulus. Based on our empirical study, the chirp stimuli visual evoked potential (Chirp-VEP) preserved frequency features of the chirp stimulus analogous to the steady state evoked potential (SSVEP), and therefore it can be regarded as a generalization of SSVEP. Specifically, we first investigated the characteristics of the Chirp-VEP in the time-frequency domain and the fractional domain via fractional Fourier transform. We also proposed a group delay technique to derive the apparent latency from Chirp-VEP. Results on EEG data showed that our approach outperformed the traditional SSVEP-based method in efficiency and ease of apparent latency estimation. For the recruited six subjects, the average apparent latencies ranged from 100 to 130 ms. Finally, we implemented a BCI system with six targets to validate the feasibility of Chirp-VEP as a potential candidate in the field of BCIs.

  3. Auditory evoked potentials in peripheral vestibular disorder individuals

    Directory of Open Access Journals (Sweden)

    Matas, Carla Gentile

    2011-07-01

    Full Text Available Introduction: The auditory and vestibular systems are located in the same peripheral receptor, however they enter the CNS and go through different ways, thus creating a number of connections and reaching a wide area of the encephalon. Despite going through different ways, some changes can impair both systems. Such tests as Auditory Evoked Potentials can help find a diagnosis when vestibular alterations are seen. Objective: describe the Auditory Evoked Potential results in individuals complaining about dizziness or vertigo with Peripheral Vestibular Disorders and in normal individuals having the same complaint. Methods: Short, middle and long latency Auditory Evoked Potentials were performed as a transversal prospective study. Conclusion: individuals complaining about dizziness or vertigo can show some changes in BAEP (Brainstem Auditory Evoked Potential, MLAEP (Medium Latency Auditory Evoked Potential and P300.

  4. Multimodal evoked potential abnormalities in patients with Wilson's disease

    Directory of Open Access Journals (Sweden)

    Ilić Tihomir V.

    2005-01-01

    Full Text Available The aim of this study was to investigate the involvement of the following functional systems: somatosensory evoked potentials (SSEP, visual evoked potentials (VEP, and event related potentials (ERP, in twenty patients with Wilson's disease (WD. VEP and SSEP abnormalities were discovered in S patients respectively (40%, whereas ERP were either absent or, in the case of 10 patients (50%, had significantly prolonged P-300 latencies. Taken together, at least one evoked potential abnormality was discovered in 17 patients (85%]. Only in 3 patients (15%, involving either the isolated hepatic type of disease or short illness duration of the neurological type, were normal evoked potential findings observed. Our findings suggest the usefulness of multimodal evoked potential abnormalities in the evaluation of subclinical manifestations in patients with WD.

  5. Segmentation Similarity and Agreement

    CERN Document Server

    Fournier, Chris

    2012-01-01

    We propose a new segmentation evaluation metric, called segmentation similarity (S), that quantifies the similarity between two segmentations as the proportion of boundaries that are not transformed when comparing them using edit distance, essentially using edit distance as a penalty function and scaling penalties by segmentation size. We propose several adapted inter-annotator agreement coefficients which use S that are suitable for segmentation. We show that S is configurable enough to suit a wide variety of segmentation evaluations, and is an improvement upon the state of the art. We also propose using inter-annotator agreement coefficients to evaluate automatic segmenters in terms of human performance.

  6. The effect of attention to distractor on inhibitory processes in selective attention

    Institute of Scientific and Technical Information of China (English)

    GENG Haiyan; SONG Qianlan; LI Yunfeng; ZHU Ying

    2005-01-01

    Selective attention has been viewed as a dualprocess mechanism, that is, exciting targets and inhibiting distractors. Most early studies concentrated mainly on the target-excitation, whereas recent investigations began to pay more attention to the inhibitory selective attention mechanism. A measure named negative priming (NP) was extensively employed to probe into the inhibitory processes. The Houghton and Tipper Model put forward a notion: the inhibition that feeds back to the distractor is reactive. That means, the level of inhibition is determined by the activation state of the distractor. Distractors that are more salient and intrude into the control of action receive greater inhibitory feedbacks than less salient distractors. Because increasing attention to an object would enhance the early processing of this object, we thus hypothesized that augmenting the level of attention to a distractor might lead to a higher level of inhibition, revealed as a corresponding augmentation in the magnitude of NP effect. To test this assumption, an object- based identification task was then applied, and participants were asked to make the animate/inanimate categorization. Attention level was manipulated by varying the relative spatial locations of target and distractor (overlapped or separated). A reliable greater NP effect was found in the overlapped than separated condition, indicating that distractors under the high-level attention condition (overlapped) got greater initial excitation, and then evoked greater subsequent inhibitory feedbacks, therefore resulting in a larger NP effect. These results provide direct evidence for the reactive inhibition suggested by the Houghton and Tipper model. Meanwhile a coincident greater positive priming (PP) effect was obtained under the overlapped than separated condition, which could be attributed to the higher level of target activation in the overlapped condition. The covariation of NP and PP effects further confirmed that the way of

  7. Glucagon-like peptide-1 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro.

    Science.gov (United States)

    Baldassano, Sara; Wang, Guo-Du; Mulè, Flavia; Wood, Jackie D

    2012-02-01

    Glucagon-like peptide-1 (GLP-1) acts at the G protein-coupled receptor, GLP-1R, to stimulate secretion of insulin and to inhibit secretion of glucagon and gastric acid. Involvement in mucosal secretory physiology has received negligible attention. We aimed to study involvement of GLP-1 in mucosal chloride secretion in the small intestine. Ussing chamber methods, in concert with transmural electrical field stimulation (EFS), were used to study actions on neurogenic chloride secretion. ELISA was used to study GLP-1R effects on neural release of acetylcholine (ACh). Intramural localization of GLP-1R was assessed with immunohistochemistry. Application of GLP-1 to serosal or mucosal sides of flat-sheet preparations in Ussing chambers did not change baseline short-circuit current (I(sc)), which served as a marker for chloride secretion. Transmural EFS evoked neurally mediated biphasic increases in I(sc) that had an initial spike-like rising phase followed by a sustained plateau-like phase. Blockade of the EFS-evoked responses by tetrodotoxin indicated that the responses were neurally mediated. Application of GLP-1 reduced the EFS-evoked biphasic responses in a concentration-dependent manner. The GLP-1 receptor antagonist exendin-(9-39) suppressed this action of GLP-1. The GLP-1 inhibitory action on EFS-evoked responses persisted in the presence of nicotinic or vasoactive intestinal peptide receptor antagonists but not in the presence of a muscarinic receptor antagonist. GLP-1 significantly reduced EFS-evoked ACh release. In the submucosal plexus, GLP-1R immunoreactivity (IR) was expressed by choline acetyltransferase-IR neurons, neuropeptide Y-IR neurons, somatostatin-IR neurons, and vasoactive intestinal peptide-IR neurons. Our results suggest that GLP-1R is expressed in guinea pig submucosal neurons and that its activation leads to a decrease in neurally evoked chloride secretion by suppressing release of ACh at neuroepithelial junctions in the enteric neural networks

  8. ROLE OF NMDA, NICOTINIC, AND GABA RECEPTORS IN THE STEADY STATE VISUAL EVOKED POTENTIAL IN RATS.

    Science.gov (United States)

    This manuscript characterizes the receptor pathways involved in pattern-evoked potential generation in rats" NMDA and nicotinic acetylcholine receptors appear to be involved in the generation of the steady-state pattern evoked response in vivo." The pattern evok...

  9. Task-dependent effects evoked by foot muscle afferents on leg muscle activity in humans.

    Science.gov (United States)

    Abbruzzese, M; Rubino, V; Schieppati, M

    1996-08-01

    The effect of low intensity electrical stimulation of the posterior tibial nerve (PTN) at the ankle on the active triceps surae (TS) muscles was studied in normal subjects, both in a prone position and while standing. PTN stimulation regularly evoked the H-reflex in the flexor digitorum brevis and, in the prone position, a short-latency facilitatory effect in the soleus muscle. During standing, the facilitatory effect was preceded by a clear-cut reduction in electromyograph (EMG) activity. The inhibition-facilitation sequence was evoked in the gastrocnemii under both conditions, on average, though individual differences were present. An EMG modulation similar to that observed under standing conditions was present also in the prone position when subjects pressed the sole of the foot against the wall. Stimulation of sural or digital nerves did not evoke similar effects. It is concluded that foot muscle afferents establish oligosynaptic connections transmitting mixed effects to the TS motoneuronal pool, and that contact with the sole of the foot plays an enabling role for the inhibitory pathway directed to the soleus muscle.

  10. Embodied Infant Attention

    Science.gov (United States)

    Robertson, Steven S.; Johnson, Sarah L.

    2009-01-01

    Does real time coupling between mental and physical activity early in development have functional significance? To address this question, we examined the habituation of visual attention and the subsequent response to change in two groups of 3-month-olds with different patterns of movement-attention coupling. In suppressors, the typical decrease in…

  11. Attention and Intelligence.

    Science.gov (United States)

    Lewis, Michael; Brooks-Gunn, Jeanne

    1981-01-01

    The authors discuss methodological and theoretical issues in psychological investigations of infant attention, fixation times, habituation, and intelligence. A consensus on how to measure individual differences in habituation has not been reached. The relation between IQ and attention is discussed. (RD)

  12. Attention and choice

    DEFF Research Database (Denmark)

    Orquin, Jacob Lund; Mueller Loose, Simone

    2013-01-01

    This paper reviews studies on eye movements in decision making, and compares their observations to theoretical predictions concerning the role of attention in decision making. Four decision theories are examined: rational models, bounded rationality, evidence accumulation, and parallel constraint...... satisfaction models. Although most theories were confirmed with regard to certain predictions, none of the theories adequately accounted for the role of attention during decision making. Several observations emerged concerning the drivers and down-stream effects of attention on choice, suggesting...... that attention processes plays an active role in constructing decisions. So far, decision theories have largely ignored the constructive role of attention by assuming that it is entirely determined by heuristics, or that it consists of stochastic information sampling. The empirical observations reveal...

  13. Dynamics of Media Attention

    CERN Document Server

    Traag, V A; Hicks, J; van Klinken, G

    2014-01-01

    Studies of human attention dynamics analyses how attention is focused on specific topics, issues or people. In online social media, there are clear signs of exogenous shocks, bursty dynamics, and an exponential or powerlaw lifetime distribution. We here analyse the attention dynamics of traditional media, focussing on co-occurrence of people in newspaper articles. The results are quite different from online social networks and attention. Different regimes seem to be operating at two different time scales. At short time scales we see evidence of bursty dynamics and fast decaying edge lifetimes and attention. This behaviour disappears for longer time scales, and in that regime we find Poissonian dynamics and slower decaying lifetimes. We propose that a cascading Poisson process may take place, with issues arising at a constant rate over a long time scale, and faster dynamics at a shorter time scale.

  14. Auditory evoked fields elicited by spectral, temporal, and spectral-temporal changes in human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Hidehiko eOkamoto

    2012-05-01

    Full Text Available Natural sounds contain complex spectral components, which are temporally modulated as time-varying signals. Recent studies have suggested that the auditory system encodes spectral and temporal sound information differently. However, it remains unresolved how the human brain processes sounds containing both spectral and temporal changes. In the present study, we investigated human auditory evoked responses elicited by spectral, temporal, and spectral-temporal sound changes by means of magnetoencephalography (MEG. The auditory evoked responses elicited by the spectral-temporal change were very similar to those elicited by the spectral change, but those elicited by the temporal change were delayed by 30 – 50 ms and differed from the others in morphology. The results suggest that human brain responses corresponding to spectral sound changes precede those corresponding to temporal sound changes, even when the spectral and temporal changes occur simultaneously.

  15. Triceps surae stretch reflex modulation after a mechanically evoked ankle dorsiflexion during the swing phase of human running.

    Science.gov (United States)

    Scohier, Mikael; De Jaeger, Dominique; Schepens, Benedicte

    2014-10-01

    The purpose of this study was to mechanically evoke a triceps surae stretch reflex during the swing phase of running, to study its within-the-step phase dependency. Seven participants ran on a treadmill at 2.8 m·s-1 wearing an exoskeleton capable of evoking a sudden ankle dorsiflexion. We measured the electromyographic activity of the soleus, medial and lateral gastrocnemii just after the perturbation to evaluate the triceps surae stretch reflex. Similar perturbations were also delivered at rest. Our results showed that the stretch reflex was suppressed during the swing phase of running, except in late swing where a late reflex response was observed. At rest, all triceps surae muscles showed an early reflex response to stretch. Our findings suggest that the triceps surae short/medium-latency stretch reflex cannot be evoked during swing phase and thus cannot contribute to the control of the locomotor pattern after aperturbation during this phase.

  16. Electroretinography and Visual Evoked Potentials in Childhood Brain Tumor Survivors.

    Science.gov (United States)

    Pietilä, Sari; Lenko, Hanna L; Oja, Sakari; Koivisto, Anna-Maija; Pietilä, Timo; Mäkipernaa, Anne

    2016-07-01

    This population-based cross-sectional study evaluates the clinical value of electroretinography and visual evoked potentials in childhood brain tumor survivors. A flash electroretinography and a checkerboard reversal pattern visual evoked potential (or alternatively a flash visual evoked potential) were done for 51 survivors (age 3.8-28.7 years) after a mean follow-up time of 7.6 (1.5-15.1) years. Abnormal electroretinography was obtained in 1 case, bilaterally delayed abnormal visual evoked potentials in 22/51 (43%) cases. Nine of 25 patients with infratentorial tumor location, and altogether 12 out of 31 (39%) patients who did not have tumors involving the visual pathways, had abnormal visual evoked potentials. Abnormal electroretinographies are rarely observed, but abnormal visual evoked potentials are common even without evident anatomic lesions in the visual pathway. Bilateral changes suggest a general and possibly multifactorial toxic/adverse effect on the visual pathway. Electroretinography and visual evoked potential may have clinical and scientific value while evaluating long-term effects of childhood brain tumors and tumor treatment.

  17. Mechanical Stimulation by Postnasal Drip Evokes Cough.

    Science.gov (United States)

    Iwata, Toshiyuki; Ito, Isao; Niimi, Akio; Ikegami, Koji; Marumo, Satoshi; Tanabe, Naoya; Nakaji, Hitoshi; Kanemitsu, Yoshihiro; Matsumoto, Hisako; Kamei, Junzo; Setou, Mitsutoshi; Mishima, Michiaki

    2015-01-01

    Cough affects all individuals at different times, and its economic burden is substantial. Despite these widespread adverse effects, cough research relies on animal models, which hampers our understanding of the fundamental cause of cough. Postnasal drip is speculated to be one of the most frequent causes of chronic cough; however, this is a matter of debate. Here we show that mechanical stimuli by postnasal drip cause chronic cough. We distinguished human cough from sneezes and expiration reflexes by airflow patterns. Cough and sneeze exhibited one-peak and two-peak patterns, respectively, in expiratory airflow, which were also confirmed by animal models of cough and sneeze. Transgenic mice with ciliary dyskinesia coughed substantially and showed postnasal drip in the pharynx; furthermore, their cough was completely inhibited by nasal airway blockade of postnasal drip. We successfully reproduced cough observed in these mice by injecting artificial postnasal drip in wild-type mice. These results demonstrated that mechanical stimulation by postnasal drip evoked cough. The findings of our study can therefore be used to develop new antitussive drugs that prevent the root cause of cough.

  18. Mechanical Stimulation by Postnasal Drip Evokes Cough.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Iwata

    Full Text Available Cough affects all individuals at different times, and its economic burden is substantial. Despite these widespread adverse effects, cough research relies on animal models, which hampers our understanding of the fundamental cause of cough. Postnasal drip is speculated to be one of the most frequent causes of chronic cough; however, this is a matter of debate. Here we show that mechanical stimuli by postnasal drip cause chronic cough. We distinguished human cough from sneezes and expiration reflexes by airflow patterns. Cough and sneeze exhibited one-peak and two-peak patterns, respectively, in expiratory airflow, which were also confirmed by animal models of cough and sneeze. Transgenic mice with ciliary dyskinesia coughed substantially and showed postnasal drip in the pharynx; furthermore, their cough was completely inhibited by nasal airway blockade of postnasal drip. We successfully reproduced cough observed in these mice by injecting artificial postnasal drip in wild-type mice. These results demonstrated that mechanical stimulation by postnasal drip evoked cough. The findings of our study can therefore be used to develop new antitussive drugs that prevent the root cause of cough.

  19. [Intraoperative monitoring of visual evoked potentials].

    Science.gov (United States)

    Sasaki, Tatsuya; Ichikawa, Tsuyoshi; Sakuma, Jun; Suzuki, Kyouichi; Matsumoto, Masato; Itakura, Takeshi; Kodama, Namio; Murakawa, Masahiro

    2006-03-01

    Our success rate of intraoperative monitoring of visual evoked potential (VEP) had been approximately 30% in the past. In order to improve recording rate of intraoperative VEP, we developed a new stimulating device using high power light emitting diodes. Electroretinogram was simultaneously recorded to understand whether flash stimulation reached the retina. In addition, total venous anesthesia with propofol was used to avoid the adverse effect of inhalation anesthesia. We report the results after introduction of these improvements. Intraoperative monitoring of VEP was attempted in 35 cases. We evaluated success rate of VEP recording, correlation between VEP findings and postoperative visual function, and reasons why recording was not successful. Stable and reproducible waveforms were obtained in 59 sides (84%). Two cases, whose VEP deteriorated intraoperatively, developed postoperative visual disturbance: In 11 sides (16%), stable waveforms were not obtained. There were two main causes. In 8 sides out of 11, the cause was attributed to pre-existing severe visual disturbance. In these 8 sides, VEP in the awake state was not recordable or was recordable, but with very low amplitudes under 1 microV. In the other 3 sides, the cause was attributed to movement of a stimulating device by reflecting the fronto-temporal scalp flap. In conclusion, the successful recording rate was increased to 84% from approximately 30%, after introduction of various trials. We need further improvement in recording intraoperative VEP to establish a reliable intraoperative monitoring method for VEP.

  20. Effects of stimulation intensity, gender and handedness upon auditory evoked potentials

    Directory of Open Access Journals (Sweden)

    Susana Camposano

    1992-03-01

    Full Text Available Left handers and women show less anatomical brain asymmetry, larger corpus callosum and more bilateral representation of specific functions. Sensory and cognitive components of cortical auditory evoked potentials (AEF have been shown to be asymmetric in right handed males and to be influenced by stimulus intensity. In this study the influence of sex, handedness and stimulus intensity upon AEP components is investigated under basal conditions of passive attention. 14 right handed males, 14 right handed females, 14 left handed males, and 14 left handed females were studied while lying awake and paying passive attention to auditory stimulation (series of 100 binaural clicks, duration 1 msec, rate 1/sec, at four intensities. Cz, C3 and C4 referenced to linked mastoids and right EOG were recorded. Analysis time was 400 msec, average evoked potentials were based on 100 clicks. Stimulus intensity and gender affect early sensory components (P1N1 and N1P2 at central leads, asymmetry is influenced only by handedness, right handers showing larger P1N1 amplitudes over the right hemisphere.

  1. Vestibular evoked myogenic potentials in patients with ankylosing spondylitis.

    Science.gov (United States)

    Özgür, Abdulkadir; Serdaroğlu Beyazal, Münevver; Terzi, Suat; Coşkun, Zerrin Özergin; Dursun, Engin

    2016-10-01

    Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease with unknown etiology. Although sacroiliac joint involvement is the classic sign along with the formed immune mediators, it may result in immune-mediated inner ear disease and may cause damage to the audiovestibular system. Vestibular evoked myogenic potentials (VEMP) is a clinical reflex test used in the diagnosis of vestibular diseases and is performed by recording and evaluating the muscle potentials resulting from the stimulation of the vestibular system with different stimuli. The aim of this study is to evaluate the cervical VEMP test results in AS patients without vestibular symptoms. Thirty-three patients with AS and a control group of 30 healthy volunteers with similar demographic characteristics were evaluated in the study. VEMP wave latency, P13-N23 wave amplitude, and VEMP asymmetry ratio (VAR) values were compared between the groups. The relationship between clinical and laboratory findings of the AS patients and VEMP data were also investigated. Compared with healthy people, this study shows the response rate of patients with ankylosing spondylitis was reduced in the VEMP test, and P13-N23 wave amplitude showed a decrease in AS patients who had VEMP response (p ankylosing spondylitis. The data obtained from this study suggest that AS may lead to decreased sensitivity of the vestibular system.

  2. More Similar Than Different

    DEFF Research Database (Denmark)

    Pedersen, Mogens Jin

    2015-01-01

    What role do employee features play into the success of different personnel management practices for serving high performance? Using data from a randomized survey experiment among 5,982 individuals of all ages, this article examines how gender conditions the compliance effects of different...... incentive treatments—each relating to the basic content of distinct types of personnel management practices. The findings show that males and females are more similar than different in terms of the incentive treatments’ effects: Significant average effects are found for three out of five incentive...

  3. [Brainstem auditory evoked potentials and somatosensory evoked potentials in Chiari malformation].

    Science.gov (United States)

    Moncho, Dulce; Poca, María A; Minoves, Teresa; Ferré, Alejandro; Rahnama, Kimia; Sahuquillo, Juan

    2013-06-16

    Introduccion. La malformacion de Chiari (MC) incluye una serie de anomalias congenitas que tienen como comun denominador la ectopia de las amigdalas del cerebelo por debajo del foramen magno, lo que puede condicionar fenomenos compresivos del troncoencefalo, la medula espinal alta y los nervios craneales, alterando las respuestas de los potenciales evocados auditivos del tronco cerebral (PEATC) y de los potenciales evocados somatosensoriales (PESS). Sin embargo, las indicaciones de ambas exploraciones en las MC han sido motivo de estudio en un numero limitado de publicaciones, centradas en series cortas y heterogeneas de pacientes. Objetivo. Revisar los hallazgos de los PEATC y los PESS en los estudios publicados en pacientes con MC tipo 1 (MC-1) o tipo 2 (MC-2), y su indicacion en el diagnostico, tratamiento y seguimiento, especialmente en la MC-1. Desarrollo. Es un estudio de revision realizado mediante analisis de los estudios publicados en Medline desde 1966, localizados mediante PubMed, utilizando combinaciones de las palabras clave 'Chiari malformation', 'Arnold-Chiari malformation', 'Chiari type 1 malformation', 'Arnold-Chiari type 1 malformation', 'evoked potentials', 'brainstem auditory evoked potentials' y 'somatosensory evoked potentials', asi como informacion de pacientes con MC-1 valorados en los servicios de neurocirugia y neurofisiologia clinica del Hospital Universitari Vall d'Hebron. Conclusiones. Los hallazgos mas comunes de los PESS son la reduccion en la amplitud cortical para el nervio tibial posterior, la reduccion o ausencia del potencial cervical del nervio mediano y el aumento del intervalo N13-N20. En el caso de los PEATC, los hallazgos mas frecuentes descritos son el aumento del intervalo I-V y la alteracion periferica o coclear.

  4. Cortical Response Variability as a Developmental Index of Selective Auditory Attention

    Science.gov (United States)

    Strait, Dana L.; Slater, Jessica; Abecassis, Victor; Kraus, Nina

    2014-01-01

    Attention induces synchronicity in neuronal firing for the encoding of a given stimulus at the exclusion of others. Recently, we reported decreased variability in scalp-recorded cortical evoked potentials to attended compared with ignored speech in adults. Here we aimed to determine the developmental time course for this neural index of auditory…

  5. Attention Sensitive Web Browsing

    OpenAIRE

    2016-01-01

    With a number of cheap commercial dry EEG kits available today, it is possible to look at user attention driven scenarios for interaction with the web browser. Using EEG to determine the user's attention level is preferable to using methods such as gaze tracking or time spent on the webpage. In this paper we use the attention level in three different ways. First, as a control mechanism, to control user interface elements such as menus or buttons. Second, to make the web browser responsive to ...

  6. Similar dissection of sets

    CERN Document Server

    Akiyama, Shigeki; Okazaki, Ryotaro; Steiner, Wolfgang; Thuswaldner, Jörg

    2010-01-01

    In 1994, Martin Gardner stated a set of questions concerning the dissection of a square or an equilateral triangle in three similar parts. Meanwhile, Gardner's questions have been generalized and some of them are already solved. In the present paper, we solve more of his questions and treat them in a much more general context. Let $D\\subset \\mathbb{R}^d$ be a given set and let $f_1,...,f_k$ be injective continuous mappings. Does there exist a set $X$ such that $D = X \\cup f_1(X) \\cup ... \\cup f_k(X)$ is satisfied with a non-overlapping union? We prove that such a set $X$ exists for certain choices of $D$ and $\\{f_1,...,f_k\\}$. The solutions $X$ often turn out to be attractors of iterated function systems with condensation in the sense of Barnsley. Coming back to Gardner's setting, we use our theory to prove that an equilateral triangle can be dissected in three similar copies whose areas have ratio $1:1:a$ for $a \\ge (3+\\sqrt{5})/2$.

  7. Evoked potentials and head injury. 1. Rating of evoked potential abnormality.

    Science.gov (United States)

    Rappaport, M; Hall, K; Hopkins, H K; Belleza, T

    1981-10-01

    This paper describes a method for rating the degree of abnormality of auditory, visual and somatosensory evoked potential patterns in head injury (HI) patients. Criteria for judging degree of EP abnormality are presented that allow assessment of the extent and severity of subcortical and cortical dysfunction associated with traumatic brain damage. Interrater reliability data based upon blind ratings of normal and HI patients are presented and shown to be highly significant. Tables of normative values of peak latencies and amplitudes are given and illustrations of EP patterns of different degrees of abnormality are presented.

  8. Are You Paying Attention?

    DEFF Research Database (Denmark)

    Ørmen, Jacob

    2016-01-01

    A still understudied area in media research is how people pay attention to news in daily life. To do so, the chapter develops a theoretical framework grounded in news audience research and practice theory. This framework conceptualizes practices as different ways in which attention is directed...... and sustained. To study such attention practices, 16 semi-structured interviews with adult Danes are carried out. Through a thematic analysis of these interviews, the chapter explores how ways of attending relate to individual media and how patterns of daily life enable some practices and constrain others....... In the concluding discussion, the chapter relates the findings to further perspectives on attention to news specifically and media content more generally. Accordingly, this chapter contributes to cross-media news research by analyzing ways in which people attend to news and how these ways of attending vary across...

  9. Attention Stabilizes Representations in the Human Hippocampus.

    Science.gov (United States)

    Aly, Mariam; Turk-Browne, Nicholas B

    2016-02-01

    Attention and memory are intricately linked, but how attention modulates brain areas that subserve memory, such as the hippocampus, is unknown. We hypothesized that attention may stabilize patterns of activity in human hippocampus, resulting in distinct but reliable activity patterns for different attentional states. To test this prediction, we utilized high-resolution functional magnetic resonance imaging and a novel "art gallery" task. On each trial, participants viewed a room containing a painting, and searched a stream of rooms for a painting from the same artist (art state) or a room with the same layout (room state). Bottom-up stimulation was the same in both tasks, enabling the isolation of neural effects related to top-down attention. Multivariate analyses revealed greater pattern similarity in all hippocampal subfields for trials from the same, compared with different, attentional state. This stability was greater for the room than art state, was unrelated to univariate activity, and, in CA2/CA3/DG, was correlated with behavior. Attention therefore induces representational stability in the human hippocampus, resulting in distinct activity patterns for different attentional states. Modulation of hippocampal representational stability highlights the far-reaching influence of attention outside of sensory systems.

  10. Similarity transformed semiclassical dynamics

    Science.gov (United States)

    Van Voorhis, Troy; Heller, Eric J.

    2003-12-01

    In this article, we employ a recently discovered criterion for selecting important contributions to the semiclassical coherent state propagator [T. Van Voorhis and E. J. Heller, Phys. Rev. A 66, 050501 (2002)] to study the dynamics of many dimensional problems. We show that the dynamics are governed by a similarity transformed version of the standard classical Hamiltonian. In this light, our selection criterion amounts to using trajectories generated with the untransformed Hamiltonian as approximate initial conditions for the transformed boundary value problem. We apply the new selection scheme to some multidimensional Henon-Heiles problems and compare our results to those obtained with the more sophisticated Herman-Kluk approach. We find that the present technique gives near-quantitative agreement with the the standard results, but that the amount of computational effort is less than Herman-Kluk requires even when sophisticated integral smoothing techniques are employed in the latter.

  11. Adaptive visual attention model

    OpenAIRE

    Hügli, Heinz; Bur, Alexandre

    2009-01-01

    Visual attention, defined as the ability of a biological or artificial vision system to rapidly detect potentially relevant parts of a visual scene, provides a general purpose solution for low level feature detection in a vision architecture. Well considered for its universal detection behaviour, the general model of visual attention is suited for any environment but inferior to dedicated feature detectors in more specific environments. The goal of the development presented in this paper is t...

  12. Attention allocation before antisaccades.

    Science.gov (United States)

    Klapetek, Anna; Jonikaitis, Donatas; Deubel, Heiner

    2016-01-01

    In the present study, we investigated the distribution of attention before antisaccades. We used a dual task paradigm, in which participants made prosaccades or antisaccades and discriminated the orientation of a visual probe shown at the saccade goal, the visual cue location (antisaccade condition), or a neutral location. Moreover, participants indicated whether they had made a correct antisaccade or an erroneous prosaccade. We observed that, while spatial attention in the prosaccade task was allocated only to the saccade goal, attention in the antisaccade task was allocated both to the cued location and to the antisaccade goal. This suggests parallel attentional selection of the cued and antisaccade locations. We further observed that in error trials--in which participants made an incorrect prosaccade instead of an antisaccade--spatial attention was biased towards the prosaccade goal. These erroneous prosaccades were mostly unnoticed and were often followed by corrective antisaccades with very short latencies (parallel programming of the reflexive prosaccade to the cue and the antisaccade to the intended location. Taken together, our results suggest that attention allocation and saccade goal selection in the antisaccade task are mediated by a common competitive process.

  13. Towards a neural basis of music-evoked emotions.

    Science.gov (United States)

    Koelsch, Stefan

    2010-03-01

    Music is capable of evoking exceptionally strong emotions and of reliably affecting the mood of individuals. Functional neuroimaging and lesion studies show that music-evoked emotions can modulate activity in virtually all limbic and paralimbic brain structures. These structures are crucially involved in the initiation, generation, detection, maintenance, regulation and termination of emotions that have survival value for the individual and the species. Therefore, at least some music-evoked emotions involve the very core of evolutionarily adaptive neuroaffective mechanisms. Because dysfunctions in these structures are related to emotional disorders, a better understanding of music-evoked emotions and their neural correlates can lead to a more systematic and effective use of music in therapy.

  14. Pudendal somatosensory evoked potentials in normal women

    Directory of Open Access Journals (Sweden)

    Geraldo A. Cavalcanti

    2007-12-01

    Full Text Available OBJECTIVE: Somatosensory evoked potential (SSEP is an electrophysiological test used to evaluate sensory innervations in peripheral and central neuropathies. Pudendal SSEP has been studied in dysfunctions related to the lower urinary tract and pelvic floor. Although some authors have already described technical details pertaining to the method, the standardization and the influence of physiological variables in normative values have not yet been established, especially for women. The aim of the study was to describe normal values of the pudendal SSEP and to compare technical details with those described by other authors. MATERIALS AND METHODS: The clitoral sensory threshold and pudendal SSEP latency was accomplished in 38 normal volunteers. The results obtained from stimulation performed on each side of the clitoris were compared to ages, body mass index (BMI and number of pregnancies. RESULTS: The values of clitoral sensory threshold and P1 latency with clitoral left stimulation were respectively, 3.64 ± 1.01 mA and 37.68 ± 2.60 ms. Results obtained with clitoral right stimulation were 3.84 ± 1.53 mA and 37.42 ± 3.12 ms, respectively. There were no correlations between clitoral sensory threshold and P1 latency with age, BMI or height of the volunteers. A significant difference was found in P1 latency between nulliparous women and volunteers who had been previously submitted to cesarean section. CONCLUSIONS: The SSEP latency represents an accessible and reproducible method to investigate the afferent pathways from the genitourinary tract. These results could be used as normative values in studies involving genitourinary neuropathies in order to better clarify voiding and sexual dysfunctions in females.

  15. Recording of electrical-evoked responses from a remote field in the vestibular part of the eighth nerve. A preliminary technical report.

    Science.gov (United States)

    Latkowski, B; Puzio, J

    1989-01-01

    The paper discusses the results of the author's own studies concerning the recording of electrical responses evoked from a remote field in the vestibular part of the eighth nerve. The studies are of experimental nature and they were carried out repetitively in guinea pigs. Particular attention is paid to an apparatus specially designed and constructed, permitting to obtain stimulation of adequate quality of vestibular organs, and to receive and average short (up to 10 ms) evoked vestibular potentials. Different variants of elimination of bioelectrical muscular disturbances and of the auditory pathway are proposed.

  16. Electrophysiological Correlates of Refreshing: Event-related Potentials Associated with Directing Reflective Attention to Face, Scene, or Word Representations.

    Science.gov (United States)

    Johnson, Matthew R; McCarthy, Gregory; Muller, Kathleen A; Brudner, Samuel N; Johnson, Marcia K

    2015-09-01

    Refreshing is the component cognitive process of directing reflective attention to one of several active mental representations. Previous studies using fMRI suggested that refresh tasks involve a component process of initiating refreshing as well as the top-down modulation of representational regions central to refreshing. However, those studies were limited by fMRI's low temporal resolution. In this study, we used EEG to examine the time course of refreshing on the scale of milliseconds rather than seconds. ERP analyses showed that a typical refresh task does have a distinct electrophysiological response as compared to a control condition and includes at least two main temporal components: an earlier (∼400 msec) positive peak reminiscent of a P3 response and a later (∼800-1400 msec) sustained positivity over several sites reminiscent of the late directing attention positivity. Overall, the evoked potentials for refreshing representations from three different visual categories (faces, scenes, words) were similar, but multivariate pattern analysis showed that some category information was nonetheless present in the EEG signal. When related to previous fMRI studies, these results are consistent with a two-phase model, with the first phase dominated by frontal control signals involved in initiating refreshing and the second by the top-down modulation of posterior perceptual cortical areas that constitutes refreshing a representation. This study also lays the foundation for future studies of the neural correlates of reflective attention at a finer temporal resolution than is possible using fMRI.

  17. Multiple Color Stimulus Induced Steady State Visual Evoked Potentials

    Science.gov (United States)

    2007-11-02

    evoked potentials, multiple color, FFT, bispectrum I. INTRODUCTION Visual evoked potential ( VEP ) is the electrical response of...brain under visual stimulation, which can be recorded from the scalp over the visual cortex of the brain. A distinction is made between transient VEP ...and steady-state VEP (SSVEP) based on the stimulation frequencies. The former arises when the stimulation frequencies are less than 2 Hz. However

  18. Investigating the periodicity of transient-evoked otoacoustic emission envelopes

    DEFF Research Database (Denmark)

    Verhulst, Sarah

    2011-01-01

    This study investigates the cochlear origin of the multiple temporal lobes that are often observed in the transient-evoked otoacoustic emission (TEOAE) envelope. This "waxing and waning" of the OAE amplitude can be observed in tone-burst (TB) OAEs and sometimes also in click-evoked (CE) OAEs. TBOAE...... and the middle-ear boundary may contribute to the TBOAE envelope periodicity, but were not the main modulation component in waxing and waning of the investigated TBOAEs....

  19. Attentional mechanisms in the generation of sympathy

    Directory of Open Access Journals (Sweden)

    Stephan Dickert

    2009-06-01

    Full Text Available Empathic responses, such as sympathy towards others, are a key ingredient in the decision to provide help to those in need. The determinants of empathic responses are usually thought to be the vividness, similarity, and proximity of the victim. However, recent research highlights the role that attention plays in the generation of feelings. We expanded on this idea by investigating whether sympathy depends on cognitive mechanisms such as attention. In two studies we found that sympathy responses were lower and reaction times were longer when targets were presented with distractors. In addition, online sympathy judgments that allow attentional focusing on a target lead to greater affective responses than judgments made from memory. We conclude that attention is an ingredient in the generation of sympathy, and discuss implications for research on prosocial behaviour and the interaction between attention and emotions.

  20. Effects of broadband noise on cortical evoked auditory responses at different loudness levels in young adults.

    Science.gov (United States)

    Sharma, Mridula; Purdy, Suzanne C; Munro, Kevin J; Sawaya, Kathleen; Peter, Varghese

    2014-03-26

    Young adults with no history of hearing concerns were tested to investigate their /da/-evoked cortical auditory evoked potentials (P1-N1-P2) recorded from 32 scalp electrodes in the presence and absence of noise at three different loudness levels (soft, comfortable, and loud), at a fixed signal-to-noise ratio (+3 dB). P1 peak latency significantly increased at soft and loud levels, and N1 and P2 latencies increased at all three levels in the presence of noise, compared with the quiet condition. P1 amplitude was significantly larger in quiet than in noise conditions at the loudest level. N1 amplitude was larger in quiet than in noise for the soft level only. P2 amplitude was reduced in the presence of noise to a similar degree at all loudness levels. The differential effects of noise on P1, N1, and P2 suggest differences in auditory processes underlying these peaks. The combination of level and signal-to-noise ratio should be considered when using cortical auditory evoked potentials as an electrophysiological indicator of degraded speech processing.

  1. Selective Attention and Attention Switching: Towards a Unified Developmental Approach

    Science.gov (United States)

    Hanania, Rima; Smith, Linda B.

    2010-01-01

    We review and relate two literatures on the development of attention in children: one concerning flexible attention switching and the other concerning selective attention. The first is a growing literature on preschool children's performances in an attention-switching task indicating that children become more flexible in their attentional control…

  2. Connectivity supporting attention in children with attention deficit hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Anita D. Barber

    2015-01-01

    While CON–DMN anti-correlation is associated with improved attention in ADHD, other circuitry supports improved attention in TD children. Greater CON–DMN anti-correlation supported better attentional control in children with ADHD, but worse attentional control in TD children. On the other hand, greater DMN–occipital anti-correlation supported better attentional control in TD children.

  3. Content-specific working memory modulation of the attentional blink

    NARCIS (Netherlands)

    Akyürek, Elkan G.; Abedian-Amiri, Ali; Ostermeier, Sonja M.

    2011-01-01

    Three experiments were conducted to investigate the effects of working memory content on temporal attention in a rapid serial visual presentation attentional blink paradigm. It was shown that categorical similarity between working memory content and the target stimuli pertaining to the attentional t

  4. Attentional load modulates responses of human primary visual cortex to invisible stimuli.

    Science.gov (United States)

    Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

    2007-03-20

    Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

  5. Normal aging selectively diminishes alpha lateralization in visual spatial attention.

    Science.gov (United States)

    Hong, Xiangfei; Sun, Junfeng; Bengson, Jesse J; Mangun, George R; Tong, Shanbao

    2015-02-01

    EEG studies of cue-induced visual alpha power (8-13 Hz) lateralization have been conducted on young adults without examining differences that may develop as a consequence of normal aging. Here, we examined age-related differences in spatial attention by comparing healthy older and younger adults. Our key finding is that cue-induced alpha power lateralization was observed in younger, but not older adults, even though both groups exhibited classic event-related potential signatures of spatial orienting. Specifically, both younger and older adults showed significant early directing-attention negativity (EDAN), anterior directing-attention negativity (ADAN), late directing-attention positivity (LDAP) and contingent negative variation (CNV). Furthermore, target-evoked sensory components were enhanced for attended relative to unattended targets in both younger and older groups. This pattern of results suggests that although older adults can successfully allocate spatial attention, they do so without the lateralization of alpha power that is commonly observed in younger adults. Taken together, our findings demonstrate that younger and older adults might engage different neural mechanisms for attentional orienting, and that alpha power lateralization during visual spatial attention is a phenomenon that diminishes during normal aging.

  6. Attention in Urban Foraging

    Directory of Open Access Journals (Sweden)

    Malcolm McCullough

    2013-05-01

    Full Text Available This position paper argues how there has to be much more to smart city learning than just wayshowing, and something better as augmented reality than covering the world with instructions. Attention has become something for many people to know better in an age of information superabundance. Embodied cognition explains how the work-ings of attention are not solely a foreground task, as if attention is something to pay. As digital media appear in ever more formats and contexts, their hybrids with physical form increasing influence how habitual engagement with persistent situations creates learning. Ambient information can just add to the distraction by multitasking, or it can support more favorable processes of shifting among different kinds of information with a particular intent. As one word for this latter process, foraging deserves more consideration in smart city learning

  7. Nonretinotopic exogenous attention.

    Science.gov (United States)

    Boi, Marco; Vergeer, Mark; Ogmen, Haluk; Herzog, Michael H

    2011-10-25

    Attention is crucial for visual perception because it allows the visual system to effectively use its limited resources by selecting behaviorally and cognitively relevant stimuli from the large amount of information impinging on the eyes. Reflexive, stimulus-driven attention is essential for successful interactions with the environment because it can, for example, speed up responses to life-threatening events. It is commonly believed that exogenous attention operates in the retinotopic coordinates of the early visual system. Here, using a novel experimental paradigm [1], we show that a nonretinotopic cue improves both accuracy and reaction times in a visual search task. Furthermore, the influence of the cue is limited both in space and time, a characteristic typical of exogenous cueing. These and other recent findings show that many more aspects of vision are processed nonretinotopically than previously thought.

  8. The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Morufu Olusola Ibitoye

    2014-07-01

    Full Text Available The evoked electromyographic signal (eEMG potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05 between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI population.

  9. Visual attention capacity

    DEFF Research Database (Denmark)

    Habekost, Thomas; Starrfelt, Randi

    2009-01-01

    Psychophysical studies have identified two distinct limitations of visual attention capacity: processing speed and apprehension span. Using a simple test, these cognitive factors can be analyzed by Bundesen's Theory of Visual Attention (TVA). The method has strong specificity and sensitivity...... to patient testing, and review existing TVA-based patient studies organized by lesion anatomy. Lesions in three anatomical regions affect visual capacity: The parietal lobes, frontal cortex and basal ganglia, and extrastriate cortex. Visual capacity thus depends on large, bilaterally distributed anatomical...... networks that include several regions outside the visual system. The two visual capacity parameters are functionally separable, but seem to rely on largely overlapping brain areas....

  10. The paradox of music-evoked sadness: an online survey.

    Science.gov (United States)

    Taruffi, Liila; Koelsch, Stefan

    2014-01-01

    This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772). The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

  11. The paradox of music-evoked sadness: an online survey.

    Directory of Open Access Journals (Sweden)

    Liila Taruffi

    Full Text Available This study explores listeners' experience of music-evoked sadness. Sadness is typically assumed to be undesirable and is therefore usually avoided in everyday life. Yet the question remains: Why do people seek and appreciate sadness in music? We present findings from an online survey with both Western and Eastern participants (N = 772. The survey investigates the rewarding aspects of music-evoked sadness, as well as the relative contribution of listener characteristics and situational factors to the appreciation of sad music. The survey also examines the different principles through which sadness is evoked by music, and their interaction with personality traits. Results show 4 different rewards of music-evoked sadness: reward of imagination, emotion regulation, empathy, and no "real-life" implications. Moreover, appreciation of sad music follows a mood-congruent fashion and is greater among individuals with high empathy and low emotional stability. Surprisingly, nostalgia rather than sadness is the most frequent emotion evoked by sad music. Correspondingly, memory was rated as the most important principle through which sadness is evoked. Finally, the trait empathy contributes to the evocation of sadness via contagion, appraisal, and by engaging social functions. The present findings indicate that emotional responses to sad music are multifaceted, are modulated by empathy, and are linked with a multidimensional experience of pleasure. These results were corroborated by a follow-up survey on happy music, which indicated differences between the emotional experiences resulting from listening to sad versus happy music. This is the first comprehensive survey of music-evoked sadness, revealing that listening to sad music can lead to beneficial emotional effects such as regulation of negative emotion and mood as well as consolation. Such beneficial emotional effects constitute the prime motivations for engaging with sad music in everyday life.

  12. Category expectation modulates baseline and stimulus-evoked activity in human inferotemporal cortex.

    Science.gov (United States)

    Puri, Amrita M; Wojciulik, Ewa; Ranganath, Charan

    2009-12-08

    Expectation of locations and low-level features increases activity in extrastriate visual areas even in the absence of a stimulus, but it is unclear whether or how expectation of higher-level stimulus properties affects visual responses. Here, we used event-related functional magnetic resonance imaging (fMRI) to test whether category expectation affects baseline and stimulus-evoked activity in higher-level, category-selective inferotemporal (IT) visual areas. Word cues indicating an image category (FACE or HOUSE) were followed by a delay, then a briefly presented image of a face or a house. On most trials, the cue correctly predicted the upcoming stimulus. Baseline activity in regions within the fusiform face area (FFA) and parahippocampal place area (PPA) was modulated such that activity was higher during expectation of the preferred (e.g., FACE for FFA) vs. non-preferred category. Stimulus-evoked responses reflected an initial bias (higher overall activity) followed by increased selectivity (greater difference between activity to a preferred vs. non-preferred stimulus) after expectation of the preferred vs. non-preferred category. Consistent with the putative role of a frontoparietal network in top-down modulation of activity in sensory cortex, expectation-related activity in several frontal and parietal areas correlated with the magnitude of baseline shifts in the FFA and PPA across subjects. Furthermore, expectation-related activity in lateral prefrontal cortex also correlated with the magnitude of expectation-based increases in stimulus selectivity in IT areas. These findings demonstrate that category expectation influences both baseline and stimulus-evoked activity in category-selective inferotemporal visual areas, and that these modulations may be driven by a frontoparietal attentional control network.

  13. Brain dynamic mechanisms on the visual attention scale with Chinese characters cues

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The temporal dynamics in brain evoked by the scale of visual attention with the cues of Chinese characters were studied by recording event-related potentials (ERPs). With the fixed orientation of visual attention, 14 healthy young participants performed a search task in which the search array was preceded by Chinese characters cues, "大, 中, 小" (large, medium, small). 128 channels scalp ERPs were recorded to study the role of visual attention scale played in the visual spatial attention. The results showed that there was no significant difference in the ERP components evoked by the three Chinese characters cues except the inferoposterior N2 latency. The targets evoked P2, N2 amplitudes and latency have significant differences with the different cues of large, middle and small, while P1 and N1 components had no significant difference. The results suggested that the processing of scale of visual attention was mainly concerned with P2, N2 components, while the P1, N1 components were mainly related with the processing of visual orientation information.

  14. Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

    Science.gov (United States)

    Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

    2014-03-01

    Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

  15. Personality and Selective Attention.

    Science.gov (United States)

    1980-03-28

    1977) have integrated information processing models of attention with social learning theory in order to conoeptualize the behavior change process...consistency at these loci. ’M Nielsen & Sarason 35 References Bandura, A. Social learning theory . Englewood Cliffs, New Jersey: Prentice- Hall, Inc

  16. Visual attention and stability

    NARCIS (Netherlands)

    Mathot, Sebastiaan; Theeuwes, Jan

    2011-01-01

    In the present review, we address the relationship between attention and visual stability. Even though with each eye, head and body movement the retinal image changes dramatically, we perceive the world as stable and are able to perform visually guided actions. However, visual stability is not as co

  17. Attention and Distraction

    DEFF Research Database (Denmark)

    Petersen, Anne Ring

    2010-01-01

    This article aims to examine the interrelationship between attention and distraction in the reception of video installation art, a genre which is commonly associated with "immersion" and an intensified feeling of presence in the discourses on new media art and installation art. This tends to veil...

  18. Pain and attention

    NARCIS (Netherlands)

    Blom, Jorian Hendry Gerwin

    2017-01-01

    The ability to sense pain may be considered as a prerequisite for human survival. The experience of pain helps humans to avoid the execution of actions that can seriously endanger their lives; pain is therefore evolutionarily predisposed to interrupt and capture attention. However, this supposed int

  19. Average is Boring: How Similarity Kills a Meme's Success

    OpenAIRE

    Coscia, Michele

    2014-01-01

    Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant di...

  20. Vestibular receptors contribute to cortical auditory evoked potentials.

    Science.gov (United States)

    Todd, Neil P M; Paillard, Aurore C; Kluk, Karolina; Whittle, Elizabeth; Colebatch, James G

    2014-03-01

    Acoustic sensitivity of the vestibular apparatus is well-established, but the contribution of vestibular receptors to the late auditory evoked potentials of cortical origin is unknown. Evoked potentials from 500 Hz tone pips were recorded using 70 channel EEG at several intensities below and above the vestibular acoustic threshold, as determined by vestibular evoked myogenic potentials (VEMPs). In healthy subjects both auditory mid- and long-latency auditory evoked potentials (AEPs), consisting of Na, Pa, N1 and P2 waves, were observed in the sub-threshold conditions. However, in passing through the vestibular threshold, systematic changes were observed in the morphology of the potentials and in the intensity dependence of their amplitude and latency. These changes were absent in a patient without functioning vestibular receptors. In particular, for the healthy subjects there was a fronto-central negativity, which appeared at about 42 ms, referred to as an N42, prior to the AEP N1. Source analysis of both the N42 and N1 indicated involvement of cingulate cortex, as well as bilateral superior temporal cortex. Our findings are best explained by vestibular receptors contributing to what were hitherto considered as purely auditory evoked potentials and in addition tentatively identify a new component that appears to be primarily of vestibular origin.

  1. A Comprehensive Review on Methodologies Employed for Visual Evoked Potentials.

    Science.gov (United States)

    Kothari, Ruchi; Bokariya, Pradeep; Singh, Smita; Singh, Ramji

    2016-01-01

    Visual information is fundamental to how we appreciate our environment and interact with others. The visual evoked potential (VEP) is among those evoked potentials that are the bioelectric signals generated in the striate and extrastriate cortex when the retina is stimulated with light which can be recorded from the scalp electrodes. In the current paper, we provide an overview of the various modalities, techniques, and methodologies which have been employed for visual evoked potentials over the years. In the first part of the paper, we cast a cursory glance on the historical aspect of evoked potentials. Then the growing clinical significance and advantages of VEPs in clinical disorders have been briefly described, followed by the discussion on the earlier and currently available methods for VEPs based on the studies in the past and recent times. Next, we mention the standards and protocols laid down by the authorized agencies. We then summarize the recently developed techniques for VEP. In the concluding section, we lay down prospective research directives related to fundamental and applied aspects of VEPs as well as offering perspectives for further research to stimulate inquiry into the role of visual evoked potentials in visual processing impairment related disorders.

  2. Feature-selective attention in healthy old age: a selective decline in selective attention?

    Science.gov (United States)

    Quigley, Cliodhna; Müller, Matthias M

    2014-02-12

    Deficient selection against irrelevant information has been proposed to underlie age-related cognitive decline. We recently reported evidence for maintained early sensory selection when older and younger adults used spatial selective attention to perform a challenging task. Here we explored age-related differences when spatial selection is not possible and feature-selective attention must be deployed. We additionally compared the integrity of feedforward processing by exploiting the well established phenomenon of suppression of visual cortical responses attributable to interstimulus competition. Electroencephalogram was measured while older and younger human adults responded to brief occurrences of coherent motion in an attended stimulus composed of randomly moving, orientation-defined, flickering bars. Attention was directed to horizontal or vertical bars by a pretrial cue, after which two orthogonally oriented, overlapping stimuli or a single stimulus were presented. Horizontal and vertical bars flickered at different frequencies and thereby elicited separable steady-state visual-evoked potentials, which were used to examine the effect of feature-based selection and the competitive influence of a second stimulus on ongoing visual processing. Age differences were found in feature-selective attentional modulation of visual responses: older adults did not show consistent modulation of magnitude or phase. In contrast, the suppressive effect of a second stimulus was robust and comparable in magnitude across age groups, suggesting that bottom-up processing of the current stimuli is essentially unchanged in healthy old age. Thus, it seems that visual processing per se is unchanged, but top-down attentional control is compromised in older adults when space cannot be used to guide selection.

  3. Effects of remote cutaneous pain on trigeminal laser-evoked potentials in migraine patients.

    Science.gov (United States)

    de Tommaso, Marina; Difruscolo, Olimpia; Sardaro, Michele; Libro, Giuseppe; Pecoraro, Carla; Serpino, Claudia; Lamberti, Paolo; Livrea, Paolo

    2007-06-01

    The present study aimed to evaluate heat pain thresholds and evoked potentials following CO(2) laser thermal stimulation (laser-evoked potentials, LEPs), during remote application of capsaicin, in migraine patients vs. non-migraine healthy controls. Twelve outpatients suffering from migraine without aura were compared with 10 healthy controls. The LEPs were recorded by 6 scalp electrodes, stimulating the dorsum of the right hand and the right supraorbital zone in basal condition, during the application of 3% capsaicin on the dorsum of the left hand and after capsaicin removal. In normal subjects, the laser pain and the N2-P2 vertex complex obtained by the hand and face stimulation were significantly reduced during remote capsaicin application, with respect to pre-and post-capsaicin conditions, while in migraine LEPs and laser pain were not significantly modified during remote painful stimulation. In migraine a defective brainstem inhibiting control may coexist with cognitive factors of focalised attention to facial pain, less sensitive to distraction by a second pain.

  4. A 3D Learning Playground for Potential Attention Training in ADHD

    DEFF Research Database (Denmark)

    Ali, Abdulla; Puthusserypady, Sadasivan

    2015-01-01

    that by moving to a higher stage in the game where the 2D environment is changed to 3D along with the added 3D distractions, the difficulty level in keeping attention on the main task increases for the subjects. Results also show a mean accuracy of 92.26 ± 7.97% and a mean average selection time of 3.07 ± 1......This paper presents a novel brain-computerinterface (BCI) system that could potentially be used for enhancing the attention ability of subjects with attention deficit hyperactivity disorder (ADHD). It employs the steady state visual evoked potential (SSVEP) paradigm. The developed system consists...

  5. Two systems drive attention to rewards

    Directory of Open Access Journals (Sweden)

    Christopher K Kovach

    2014-02-01

    Full Text Available How options are framed can dramatically influence choice preference. While salience of information plays a central role in this effect, precisely how it is mediated by attentional processes remains unknown. Current models assume a simple relationship between attention and choice, according to which attention should uniformly bias preference towards the attended item over the whole time-course of a decision between similarly valued items. To test this prediction we considered how framing alters attention during a simple choice between two options, using eye movements as a sensitive online measure of attention. In one condition participants selected the less preferred item to discard and in the other, the more preferred item to keep. We replicated the well-known observation that gaze gravitates towards the item ultimately selected, but did not observe the effect to be uniform over time. Instead, we found evidence for distinct early and late processes that guide attention according to preference in the first case and task demands in the second. We conclude that multiple time-dependent processes govern attention during choice, and that these may contribute to framing effects in different ways.

  6. Neuronal Rac1 is required for learning-evoked neurogenesis

    DEFF Research Database (Denmark)

    Haditsch, Ursula; Anderson, Matthew P; Freewoman, Julia

    2013-01-01

    neurons for normal synaptic plasticity in vivo, and here we show that selective loss of neuronal Rac1 also impairs the learning-evoked increase in neurogenesis in the adult mouse hippocampus. Earlier work has indicated that experience elevates the abundance of adult-born neurons in the hippocampus...... primarily by enhancing the survival of neurons produced just before the learning event. Loss of Rac1 in mature projection neurons did reduce learning-evoked neurogenesis but, contrary to our expectations, these effects were not mediated by altering the survival of young neurons in the hippocampus. Instead......, loss of neuronal Rac1 activation selectively impaired a learning-evoked increase in the proliferation and accumulation of neural precursors generated during the learning event itself. This indicates that experience-induced alterations in neurogenesis can be mechanistically resolved into two effects: (1...

  7. Temporal resolution in the hearing system and auditory evoked potentials

    DEFF Research Database (Denmark)

    Miller, Lee; Beedholm, Kristian

    2008-01-01

    3pAB5. Temporal resolution in the hearing system and auditory evoked potentials. Kristian Beedholm Institute of Biology,University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark, beedholm@mail.dk, Lee A. Miller Institute of Biology,University of Southern Denmark, Campusvej 55, 5230...... Odense M, Denmark, lee@biology.sdu.dkA popular type of investigation with auditory evoked potentials AEP consists of mapping the dependency of the envelope followingresponse to the AM frequency. This results in what is called the modulation rate transfer function MRTF. The physiologicalinterpretation...... of the MRTF is not straight forward, but is often used as a measure of the ability of the auditory system to encodetemporal changes. It is, however, shown here that the MRTF must depend on the waveform of the click-evoked AEP ceAEP, whichdoes not relate directly to temporal resolution. The theoretical...

  8. Stimulator with arbitrary waveform for auditory evoked potentials

    Energy Technology Data Exchange (ETDEWEB)

    Martins, H R; Romao, M; Placido, D; Provenzano, F; Tierra-Criollo, C J [Universidade Federal de Minas Gerais (UFMG), Departamento de Engenharia Eletrica (DEE), Nucleo de Estudos e Pesquisa em Engenharia Biomedica NEPEB, Av. Ant. Carlos, 6627, sala 2206, Pampulha, Belo Horizonte, MG, 31.270-901 (Brazil)

    2007-11-15

    The technological improvement helps many medical areas. The audiometric exams involving the auditory evoked potentials can make better diagnoses of auditory disorders. This paper proposes the development of a stimulator based on Digital Signal Processor. This stimulator is the first step of an auditory evoked potential system based on the ADSP-BF533 EZ KIT LITE (Analog Devices Company - USA). The stimulator can generate arbitrary waveform like Sine Waves, Modulated Amplitude, Pulses, Bursts and Pips. The waveforms are generated through a graphical interface programmed in C++ in which the user can define the parameters of the waveform. Furthermore, the user can set the exam parameters as number of stimuli, time with stimulation (Time ON) and time without stimulus (Time OFF). In future works will be implemented another parts of the system that includes the acquirement of electroencephalogram and signal processing to estimate and analyze the evoked potential.

  9. Individual Differences in Attention.

    Science.gov (United States)

    1980-09-01

    Psychology Technical Report, August, 1977. It Attention 50 References Atkinson , R.C., & Shiffrin , R.M. Human memory : A proposed system and its control...referred to as a continuous paired assoc- iates task. The present form was developed by Atkinson and Shiffrin (1968), who used it to test their buffer...They found that digit memori - zation Interfered with sentence comprehension. Baddeley and Hitch’s inter- pretation was that the two tasks competed for

  10. Don't forget the lyrics! Spatiotemporal dynamics of neural mechanisms spontaneously evoked by gaps of silence in familiar and newly learned songs.

    Science.gov (United States)

    Gabriel, Damien; Wong, Thian Chiew; Nicolier, Magali; Giustiniani, Julie; Mignot, Coralie; Noiret, Nicolas; Monnin, Julie; Magnin, Eloi; Pazart, Lionel; Moulin, Thierry; Haffen, Emmanuel; Vandel, Pierre

    2016-07-01

    The vast majority of people experience musical imagery, the sensation of reliving a song in absence of any external stimulation. Internal perception of a song can be deliberate and effortful, but also may occur involuntarily and spontaneously. Moreover, musical imagery is also involuntarily used for automatically completing missing parts of music or lyrics from a familiar song. The aim of our study was to explore the onset of musical imagery dynamics that leads to the automatic completion of missing lyrics. High-density electroencephalography was used to record the cerebral activity of twenty healthy volunteers while they were passively listening to unfamiliar songs, very familiar songs, and songs previously listened to for two weeks. Silent gaps inserted into these songs elicited a series of neural activations encompassing perceptual, attentional and cognitive mechanisms (range 100-500ms). Familiarity and learning effects emerged as early as 100ms and lasted 400ms after silence occurred. Although participants reported more easily mentally imagining lyrics in familiar rather than passively learnt songs, the onset of neural mechanisms and the power spectrum underlying musical imagery were similar for both types of songs. This study offers new insights into the musical imagery dynamics evoked by gaps of silence and on the role of familiarity and learning processes in the generation of these dynamics. The automatic and effortless method presented here is a potentially useful tool to understand failure in the familiarity and learning processes of pathological populations.

  11. Estimating similarity of XML Schemas using path similarity measure

    Directory of Open Access Journals (Sweden)

    Veena Trivedi

    2012-07-01

    Full Text Available In this paper, an attempt has been made to develop an algorithm which estimates the similarity for XML Schemas using multiple similarity measures. For performing the task, the XML Schema element information has been represented in the form of string and four different similarity measure approaches have been employed. To further improve the similarity measure, an overall similarity measure has also been calculated. The approach used in this paper is a distinguished one, as it calculates the similarity between two XML schemas using four approaches and gives an integrated values for the similarity measure. Keywords-componen

  12. Selective Attention and Attention Switching: Toward a Unified Developmental Approach

    OpenAIRE

    Hanania, Rima; Smith, Linda B.

    2010-01-01

    We review and relate two literatures on the development of attention in children: one concerning flexible attention switching and the other concerning selective attention. The first is a growing literature on preschool children’s performances in an attention switching task indicating that children become more flexible in their attentional control during the preschool years. The second literature encompasses a large and robust set of phenomena for the same developmental period that indicate a ...

  13. Evaluation of Visual Evoked Potential (VEP) in Patients With Chronic Obstructive Pulmonary Disease (COPD).

    Science.gov (United States)

    Karthikkeyan, Kanmani; Padma, K; Rao, B Vishwanatha

    2015-01-01

    Chronic Obstructive Pulmonary Disease (COPD), a progressive and partially reversible disease, has drawn world-wide attention for its moderate prevalence rate and causing central and peripheral neuropathy. Considering its severity in causing visual pathway impairment, the present investigation was carried out to find out the functional integrity of the visual pathway through visual evoked potentials (VEP) and to determine the factors influencing the condition in COPD patients. A total of 30 COPD patients of both sexes, classified according to the severity of the disease based on spirometric indices, were subjected to VEP testing and series of wave forms were measured and compared with equal number of control subjects. The latency of N75 and P100 were prolonged (P VEP changes. Non-invasive procedure can possibly be utilized as a routine screening test for COPD patients for better medical care.

  14. Promoting public health messages: Should we move beyond fear-evoking appeals in road safety?

    Science.gov (United States)

    Lewis, Ioni M; Watson, Barry; White, Katherine M; Tay, Richard

    2007-01-01

    Road traffic injury is one of the most significant global public health issues of the 21st century. The extent to which negative, fear-evoking messages represent effective persuasive strategies remains a contentious public and empirical issue. Nevertheless, negative, fear-based appeals represent a frequently used approach in Australasian road safety advertising. The authors conducted a series of focus groups with 16 licensed drivers to explore the potential utility of appeals to emotions other than fear. More specifically, they sought to explore the utility of positive emotional appeals, such as those incorporating humor. The themes emerging from the qualitative analysis suggested that both emotion and the provision of strategies are key components contributing to the overall persuasiveness of a road safety advertisement. Overall, it appears there is support for researchers and health advertising practitioners to provide further attention to the role that positive emotional appeals might play in future campaigns.

  15. Face processing is gated by visual spatial attention

    Directory of Open Access Journals (Sweden)

    Roy E Crist

    2008-03-01

    Full Text Available Human perception of faces is widely believed to rely on automatic processing by a domain-specifi c, modular component of the visual system. Scalp-recorded event-related potential (ERP recordings indicate that faces receive special stimulus processing at around 170 ms poststimulus onset, in that faces evoke an enhanced occipital negative wave, known as the N170, relative to the activity elicited by other visual objects. As predicted by modular accounts of face processing, this early face-specifi c N170 enhancement has been reported to be largely immune to the infl uence of endogenous processes such as task strategy or attention. However, most studies examining the infl uence of attention on face processing have focused on non-spatial attention, such as object-based attention, which tend to have longer-latency effects. In contrast, numerous studies have demonstrated that visual spatial attention can modulate the processing of visual stimuli as early as 80 ms poststimulus – substantially earlier than the N170. These temporal characteristics raise the question of whether this initial face-specifi c processing is immune to the infl uence of spatial attention. This question was addressed in a dual-visualstream ERP study in which the infl uence of spatial attention on the face-specifi c N170 could be directly examined. As expected, early visual sensory responses to all stimuli presented in an attended location were larger than responses evoked by those same stimuli when presented in an unattended location. More importantly, a signifi cant face-specifi c N170 effect was elicited by faces that appeared in an attended location, but not in an unattended one. In summary, early face-specifi c processing is not automatic, but rather, like other objects, strongly depends on endogenous factors such as the allocation of spatial attention. Moreover, these fi ndings underscore the extensive infl uence that top-down attention exercises over the processing of

  16. Mindfulness Meditation Improves Mood, Quality of Life, and Attention in Adults with Attention Deficit Hyperactivity Disorder

    Science.gov (United States)

    Bueno, Viviane Freire; Kozasa, Elisa H.; da Silva, Maria Aparecida; Alves, Tânia Maria; Louzã, Mario Rodrigues; Pompéia, Sabine

    2015-01-01

    Objective. Adults with attention deficit hyperactivity disorder (ADHD) display affective problems and impaired attention. Mood in ADHD can be improved by mindful awareness practices (MAP), but results are mixed regarding the enhancement of attentional performance. Here we evaluated MAP-induced changes in quality of life (QoL), mood, and attention in adult ADHD patients and controls using more measures of attention than prior studies. Methods. Twenty-one ADHD patients and 8 healthy controls underwent 8 weekly MAP sessions; 22 similar patients and 9 controls did not undergo the intervention. Mood and QoL were assessed using validated questionnaires, and attention was evaluated using the Attentional Network Test (ANT) and the Conners Continuous Performance Test (CPT II), before and after intervention. Results. MAP enhanced sustained attention (ANT) and detectability (CPT II) and improved mood and QoL of patients and controls. Conclusion. MAP is a complementary intervention that improves affect and attention of adults with ADHD and controls. PMID:26137496

  17. Mindfulness Meditation Improves Mood, Quality of Life, and Attention in Adults with Attention Deficit Hyperactivity Disorder

    Directory of Open Access Journals (Sweden)

    Viviane Freire Bueno

    2015-01-01

    Full Text Available Objective. Adults with attention deficit hyperactivity disorder (ADHD display affective problems and impaired attention. Mood in ADHD can be improved by mindful awareness practices (MAP, but results are mixed regarding the enhancement of attentional performance. Here we evaluated MAP-induced changes in quality of life (QoL, mood, and attention in adult ADHD patients and controls using more measures of attention than prior studies. Methods. Twenty-one ADHD patients and 8 healthy controls underwent 8 weekly MAP sessions; 22 similar patients and 9 controls did not undergo the intervention. Mood and QoL were assessed using validated questionnaires, and attention was evaluated using the Attentional Network Test (ANT and the Conners Continuous Performance Test (CPT II, before and after intervention. Results. MAP enhanced sustained attention (ANT and detectability (CPT II and improved mood and QoL of patients and controls. Conclusion. MAP is a complementary intervention that improves affect and attention of adults with ADHD and controls.

  18. [Evoked potentials in intracranial operations: current status and our experiences].

    Science.gov (United States)

    Nau, H E; Hess, W; Pohlen, G; Marggraf, G; Rimpel, J

    1987-03-01

    Intraoperative neuromonitoring, especially evoked potential monitoring, has gained interest in recent years for both the anesthesiologist evaluating cerebral function and the neurosurgeon wishing to avoid neuronal lesions during intracranial operations. Before evoked potential monitoring can be introduced as a routine method of intraoperative management, experience with this method particularly in intensive care units, is imperative. We recorded evoked potentials with the Compact Four (Nicolet) and Basis 8000 (Schwarzer Picker International) computer systems. Preoperative derivations should be done with the same apparatus used intraoperatively and parameters of peri- and intraoperative derivations should not be changed. The patient's head must be fixed in a Mayfield clamp in order to avoid artefacts during trepanation. The possible artefacts due to apparatus, patient, or anesthesia are summarized in the tables. The derivations of evoked potentials should be supervised by a person who is not involved in the anesthesia or the surgical procedure; this condition may change in the future with full automatization of the recording technique and alarms. Good communication between surgeon, anesthesiologist, and neurophysiological assistant is a prerequisite. The modality is chosen in accordance with the affected neuronal system: visual-evoked potential (VEP) monitoring in the management of processes affecting the visual pathway, brain stem auditory-(BAER) and somatosensory-evoked potential (SSEP) monitoring in lesions affecting these pathways, in particular space-occupying lesions of the posterior fossa. VEP monitoring may be useful, but we observed alterations of the responses without changes in the level of anesthesia or manipulation of the visual pathways. In space-occupying processes of the cerebellopontine angle, BAER could not be developed in nearly all cases because the large underlying tumor had caused the disappearance of waves II-V. In these cases SSEP monitoring

  19. Apolipoprotein E4 reduces evoked hippocampal acetylcholine release in adult mice.

    Science.gov (United States)

    Dolejší, Eva; Liraz, Ori; Rudajev, Vladimír; Zimčík, Pavel; Doležal, Vladimír; Michaelson, Daniel M

    2016-02-01

    Apolipoprotein E4 (apoE4) is the most prevalent genetic risk factor for Alzheimer's disease. We utilized apoE4-targeted replacement mice (approved by the Tel Aviv University Animal Care Committee) to investigate whether cholinergic dysfunction, which increases during aging and is a hallmark of Alzheimer's disease, is accentuated by apoE4. This revealed that levels of the pre-synaptic cholinergic marker, vesicular acetylcholine transporter in the hippocampus and the corresponding electrically evoked release of acetylcholine, are similar in 4-month-old apoE4 and apolipoprotein E3 (apoE3) mice. Both parameters decrease with age. This decrease is, however, significantly more pronounced in the apoE4 mice. The levels of cholinacetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) were similar in the hippocampus of young apoE4 and apoE3 mice and decreased during aging. For ChAT, this decrease was similar in the apoE4 and apoE3 mice, whereas it was more pronounced in the apoE4 mice, regarding their corresponding AChE and BuChE levels. The level of muscarinic receptors was higher in the apoE4 than in the apoE3 mice at 4 months and increased to similar levels with age. However, the relative representation of the M1 receptor subtype decreased during aging in apoE4 mice. These results demonstrate impairment of the evoked release of acetylcholine in hippocampus by apoE4 in 12-month-old mice but not in 4-month-old mice. The levels of ChAT and the extent of the M2 receptor-mediated autoregulation of ACh release were similar in the adult mice, suggesting that the apoE4-related inhibition of hippocampal ACh release in these mice is not driven by these parameters. Evoked ACh release from hippocampal and cortical slices is similar in 4-month-old apoE4 and apoE3 mice but is specifically and significantly reduced in hippocampus, but not cortex, of 12-month-old apoE4 mice. This effect is accompanied by decreased VAChT levels. These findings show that

  20. Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.

    Directory of Open Access Journals (Sweden)

    Jorge Arrubla

    Full Text Available Simultaneous recording of electroencephalography (EEG and functional magnetic resonance imaging (fMRI has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP. Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses.

  1. Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.

    Science.gov (United States)

    Arrubla, Jorge; Neuner, Irene; Hahn, David; Boers, Frank; Shah, N Jon

    2013-01-01

    Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses.

  2. Attentional selection by distractor suppression.

    Science.gov (United States)

    Caputo, G; Guerra, S

    1998-03-01

    Selective attention was studied in displays containing singletons popping out for their odd form or color. The target was defined as the form-singleton, the distractor as the color-singleton. The task was to discriminate the length of a longer line inside the target. Target-distractor similarity was controlled using a threshold measurement as dependent variable in experiments in which distractor presence vs absence, bottom-up vs top-down selection (through knowledge of target features), and target-distractor distance were manipulated. The results in the bottom-up condition showed that length threshold was elevated when a distractor was present and that this elevation progressively increased as the number of distractors was increased from one to two. This set-size effect was not accounted by the hypothesis that selective attention intervenes only at the stage of decision before response. Selective attention produced a suppressive surround in which discriminability of neighboring objects was strongly reduced, and a larger surround in which discriminability was reduced by an approximately constant amount. Different results were found in the top-down condition in which target discriminability was unaffected by distractor presence and no effect of target-distractor distance was found. On the other hand, response times in both bottom-up and top-down conditions were slower the shorter the target-distractor distance was. On the basis of the experimental results, selective attention is a parallel process of spatial filtering at an intermediate processing level operating after objects have been segmented. This filtering stage explores high level interactions between objects taking control on combinatorial explosion by operating over only a limited spatial extent: it picks out a selected object and inhibits the neighboring objects; then, non-selected objects are suppressed across the overall image. When no feature-based selection is available in the current behavior, this

  3. Attention, Predation, Counterintuition

    DEFF Research Database (Denmark)

    Clasen, Mathias

    2012-01-01

    Bram Stoker’s seminal horror novel Dracula (1897) has been subjected to a vast number of different critical readings, many of which are deeply flawed, e.g. by proceeding from defunct psychological theories. Incorporating recent advances in evolutionary social science, I offer a biocultural reading...... of Dracula to account for the novel’s impact and resilience. Dracula connected squarely with late-Victorian anxieties, but the novel also appeals to trans-historical adaptive dispositions. I analyze Stoker’s use of narrative strategies to grab and sustain attention, and Count Dracula as a supercharged...

  4. Neurofibromatozis and Attention Deficit

    Directory of Open Access Journals (Sweden)

    Mehmet ERYILMAZ et al.

    2010-05-01

    Full Text Available Neurofibromatosis type VI, a disease characterized by the presence of café-au-lait spots withoutthe presence of neurofibromas typically present in neurofibromatosis, as well as cognitivefunction and speech problems, often shows neurological involvement. We describe a case of a14-year-old child who has speech problems and isolated cafè-au-lait macules. We performedan IQ test on him and he scored 70 points. His problems started when he was approximately 5years old (school age. He was diagnosed with attention deficit disorder syndrome withouthyperactivity after neuropsychiatric investigation. We reported this case to improve recognitionof NF VI in children who have cognitive function problems.

  5. Thermal grill conditioning: Effect on contact heat evoked potentials

    Science.gov (United States)

    Jutzeler, Catherine R.; Warner, Freda M.; Wanek, Johann; Curt, Armin; Kramer, John L. K.

    2017-01-01

    The ‘thermal grill illusion’ (TGI) is a unique cutaneous sensation of unpleasantness, induced through the application of interlacing warm and cool stimuli. While previous studies have investigated optimal parameters and subject characteristics to evoke the illusion, our aim was to examine the modulating effect as a conditioning stimulus. A total of 28 healthy control individuals underwent three testing sessions on separate days. Briefly, 15 contact heat stimuli were delivered to the right hand dorsum, while the left palmar side of the hand was being conditioned with either neutral (32 °C), cool (20 °C), warm (40 °C), or TGI (20/40 °C). Rating of perception (numeric rating scale: 0–10) and evoked potentials (i.e., N1 and N2P2 potentials) to noxious contact heat stimuli were assessed. While cool and warm conditioning decreased cortical responses to noxious heat, TGI conditioning increased evoked potential amplitude (N1 and N2P2). In line with other modalities of unpleasant conditioning (e.g., sound, visual, and olfactory stimulation), cortical and possibly sub-cortical modulation may underlie the facilitation of contact heat evoked potentials. PMID:28079118

  6. Asymmetric vestibular evoked myogenic potentials in unilateral Meniere patients

    NARCIS (Netherlands)

    Kingma, C. M.; Wit, H. P.

    2011-01-01

    Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral MeniSre patients with monaural and binaural stimulation with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured at the affected side compared to the unaff

  7. Value of transcranial motor evoked potentials during spinal operations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ To the Editor: We read the interesting recent article by Ding et al1 concerning the value of somatosensory evoked potentials (SEPs) in the diagnosis and prognosis of cervical spondylotic myelopathy, as well as the usefulness of monitoring intraoperative potentials in terms of safety and predictive factors.

  8. Evaluation of Evoked Potentials to Dyadic Tones after Cochlear Implantation

    Science.gov (United States)

    Sandmann, Pascale; Eichele, Tom; Buechler, Michael; Debener, Stefan; Jancke, Lutz; Dillier, Norbert; Hugdahl, Kenneth; Meyer, Martin

    2009-01-01

    Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of…

  9. Recording and assessment of evoked potentials with electrode arrays.

    Science.gov (United States)

    Miljković, N; Malešević, N; Kojić, V; Bijelić, G; Keller, T; Popović, D B

    2015-09-01

    In order to optimize procedure for the assessment of evoked potentials and to provide visualization of the flow of action potentials along the motor systems, we introduced array electrodes for stimulation and recording and developed software for the analysis of the recordings. The system uses a stimulator connected to an electrode array for the generation of evoked potentials, an electrode array connected to the amplifier, A/D converter and computer for the recording of evoked potentials, and a dedicated software application. The method has been tested for the assessment of the H-reflex on the triceps surae muscle in six healthy humans. The electrode array with 16 pads was positioned over the posterior aspect of the thigh, while the recording electrode array with 16 pads was positioned over the triceps surae muscle. The stimulator activated all the pads of the stimulation electrode array asynchronously, while the signals were recorded continuously at all the recording sites. The results are topography maps (spatial distribution of evoked potentials) and matrices (spatial visualization of nerve excitability). The software allows the automatic selection of the lowest stimulation intensity to achieve maximal H-reflex amplitude and selection of the recording/stimulation pads according to predefined criteria. The analysis of results shows that the method provides rich information compared with the conventional recording of the H-reflex with regard the spatial distribution.

  10. Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users

    Science.gov (United States)

    Munivrana, Boska; Mildner, Vesna

    2013-01-01

    In some cochlear implant users, success is not achieved in spite of optimal clinical factors (including age at implantation, duration of rehabilitation and post-implant hearing level), which may be attributed to disorders at higher levels of the auditory pathway. We used cortical auditory evoked potentials to investigate the ability to perceive…

  11. SOMATOSENSORY EVOKED-POTENTIALS IN CEREBRAL ANEURYSM SURGERY

    NARCIS (Netherlands)

    BUCHTHAL, A; BELOPAVLOVIC, M

    1992-01-01

    Monitoring of median nerve somatosensory evoked potentials (SSEP) during surgery for a basilar artery aneurysm under moderate hypothermia revealed an unexpected loss of the first cortical peak. This was due to compression of the middle cerebral artery under the retractor during the surgical approach

  12. Analysis and Treatment of Problem Behavior Evoked by Music

    Science.gov (United States)

    Buckley, Scott D.; Newchok, Debra K.

    2006-01-01

    The present study investigated the effects of differential negative reinforcement of other behavior (DNRO) on problem behavior evoked by music in a 7-year-old child with pervasive developmental disorder. Following an auditory stimulus assessment, DNRO was used to reduce problem behavior to near-zero levels. Results are discussed in terms of…

  13. Cortical Variability in the Sensory-Evoked Response in Autism

    Science.gov (United States)

    Haigh, Sarah M.; Heeger, David J.; Dinstein, Ilan; Minshew, Nancy; Behrmann, Marlene

    2015-01-01

    Previous findings have shown that individuals with autism spectrum disorder (ASD) evince greater intra-individual variability (IIV) in their sensory-evoked fMRI responses compared to typical control participants. We explore the robustness of this finding with a new sample of high-functioning adults with autism. Participants were presented with…

  14. Multichannel recording of tibial-nerve somatosensory evoked potentials

    NARCIS (Netherlands)

    de Wassenberg, W. J. G. van; Kruizinga, W. J.; van der Hoeven, J. H.; Leenders, K. L.; Maurits, N. M.

    2008-01-01

    Study aims. -The topography of the peaks of tibial.-nerve somatosensory evoked potential (SEP) varies among healthy subjects, most likely because of differences in position and orientation of their cortical generator(s). Therefore, amplitude estimation with a standard one- or two-channel derivation

  15. Cortical Inhibition in Attention Deficit Hyperactivity Disorder: New Insights from the Electroencephalographic Response to Transcranial Magnetic Stimulation

    Science.gov (United States)

    Bruckmann, Sarah; Hauk, Daniela; Roessner, Veit; Resch, Franz; Freitag, Christine M.; Kammer, Thomas; Ziemann, Ulf; Rothenberger, Aribert; Weisbrod, Matthias; Bender, Stephan

    2012-01-01

    Attention deficit hyperactivity disorder is one of the most frequent neuropsychiatric disorders in childhood. Transcranial magnetic stimulation studies based on muscle responses (motor-evoked potentials) suggested that reduced motor inhibition contributes to hyperactivity, a core symptom of the disease. Here we employed the N100 component of the…

  16. Global Enhancement but Local Suppression in Feature-based Attention.

    Science.gov (United States)

    Forschack, Norman; Andersen, Søren K; Müller, Matthias M

    2017-04-01

    A key property of feature-based attention is global facilitation of the attended feature throughout the visual field. Previously, we presented superimposed red and blue randomly moving dot kinematograms (RDKs) flickering at a different frequency each to elicit frequency-specific steady-state visual evoked potentials (SSVEPs) that allowed us to analyze neural dynamics in early visual cortex when participants shifted attention to one of the two colors. Results showed amplification of the attended and suppression of the unattended color as measured by SSVEP amplitudes. Here, we tested whether the suppression of the unattended color also operates globally. To this end, we presented superimposed flickering red and blue RDKs in the center of a screen and a red and blue RDK in the left and right periphery, respectively, also flickering at different frequencies. Participants shifted attention to one color of the superimposed RDKs in the center to discriminate coherent motion events in the attended from the unattended color RDK, whereas the peripheral RDKs were task irrelevant. SSVEP amplitudes elicited by the centrally presented RDKs confirmed the previous findings of amplification and suppression. For peripherally located RDKs, we found the expected SSVEP amplitude increase, relative to precue baseline when color matched the one of the centrally attended RDK. We found no reduction in SSVEP amplitude relative to precue baseline, when the peripheral color matched the unattended one of the central RDK, indicating that, while facilitation in feature-based attention operates globally, suppression seems to be linked to the location of focused attention.

  17. Visual evoked potentials in patients after methanol poisoning

    Directory of Open Access Journals (Sweden)

    Pavel Urban

    2016-06-01

    Full Text Available Objectives: We report the results of the visual evoked potentials (VEP examination in patients after severe poisoning by methanol. Material and Methods: The group of 47 patients (38 males and 9 females was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012–2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test were used to analyze factors influencing the VEP abnormality. Results: The visual evoked potential was abnormal in 20 patients (43%, 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04. The abnormality was not related to chronic alcohol abuse. Conclusions: The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1–9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae.

  18. Calcium transient evoked by nicotine in isolated rat vagal pulmonary sensory neurons.

    Science.gov (United States)

    Xu, Jennings; Yang, Wenbin; Zhang, Guangfan; Gu, Qihai; Lee, Lu-Yuan

    2007-01-01

    It has been shown that inhaled cigarette smoke activates vagal pulmonary C fibers and rapidly adapting receptors (RARs) in the airways and that nicotine contained in the smoke is primarily responsible. This study was carried out to determine whether nicotine alone can activate pulmonary sensory neurons isolated from rat vagal ganglia; the response of these neurons was determined by fura-2-based ratiometric Ca(2+) imaging. The results showed: 1) Nicotine (10(-4) M, 20 s) evoked a transient increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in 175 of the 522 neurons tested (Delta[Ca(2+)](i) = 142.2 +/- 12.3 nM); the response was reproducible, with a small reduction in peak amplitude in the same neurons when the challenge was repeated 20 min later. 2) A majority (59.7%) of these nicotine-sensitive neurons were also activated by capsaicin (10(-7) M). 3) 1,1-Dimethyl-4-phenylpiperazinium iodide (DMPP; 10(-4) M, 20 s), a selective agonist of the neuronal nicotinic acetylcholine receptors (NnAChRs), evoked a pattern of response similar to that of nicotine. 4) The responses to nicotine and DMPP were either totally abrogated or markedly attenuated by hexamethonium (10(-4) M). 5) In anesthetized rats, right atrial bolus injection of nicotine (75-200 mug/kg) evoked an immediate (latency <1-2 s) and intense burst of discharge in 47.8% of the pulmonary C-fiber endings and 28.6% of the RARs tested. In conclusion, nicotine exerts a direct stimulatory effect on vagal pulmonary sensory nerves, and the effect is probably mediated through an activation of the NnAChRs expressed on the membrane of these neurons.

  19. Similarity measures for protein ensembles

    DEFF Research Database (Denmark)

    Lindorff-Larsen, Kresten; Ferkinghoff-Borg, Jesper

    2009-01-01

    Analyses of similarities and changes in protein conformation can provide important information regarding protein function and evolution. Many scores, including the commonly used root mean square deviation, have therefore been developed to quantify the similarities of different protein conformatio...

  20. Facilitating neuronal connectivity analysis of evoked responses by exposing local activity with principal component analysis preprocessing: simulation of evoked MEG.

    Science.gov (United States)

    Gao, Lin; Zhang, Tongsheng; Wang, Jue; Stephen, Julia

    2013-04-01

    When connectivity analysis is carried out for event related EEG and MEG, the presence of strong spatial correlations from spontaneous activity in background may mask the local neuronal evoked activity and lead to spurious connections. In this paper, we hypothesized PCA decomposition could be used to diminish the background activity and further improve the performance of connectivity analysis in event related experiments. The idea was tested using simulation, where we found that for the 306-channel Elekta Neuromag system, the first 4 PCs represent the dominant background activity, and the source connectivity pattern after preprocessing is consistent with the true connectivity pattern designed in the simulation. Improving signal to noise of the evoked responses by discarding the first few PCs demonstrates increased coherences at major physiological frequency bands when removing the first few PCs. Furthermore, the evoked information was maintained after PCA preprocessing. In conclusion, it is demonstrated that the first few PCs represent background activity, and PCA decomposition can be employed to remove it to expose the evoked activity for the channels under investigation. Therefore, PCA can be applied as a preprocessing approach to improve neuronal connectivity analysis for event related data.

  1. Functional Similarity and Interpersonal Attraction.

    Science.gov (United States)

    Neimeyer, Greg J.; Neimeyer, Robert A.

    1981-01-01

    Students participated in dyadic disclosure exercises over a five-week period. Results indicated members of high functional similarity dyads evidenced greater attraction to one another than did members of low functional similarity dyads. "Friendship" pairs of male undergraduates displayed greater functional similarity than did "nominal" pairs from…

  2. Culture, attention, and emotion.

    Science.gov (United States)

    Grossmann, Igor; Ellsworth, Phoebe C; Hong, Ying-yi

    2012-02-01

    This research provides experimental evidence for cultural influence on one of the most basic elements of emotional processing: attention to positive versus negative stimuli. To this end, we focused on Russian culture, which is characterized by brooding and melancholy. In Study 1, Russians spent significantly more time looking at negative than positive pictures, whereas Americans did not show this tendency. In Study 2, Russian Latvians were randomly primed with symbols of each culture, after which we measured the speed of recognition for positive versus negative trait words. Biculturals were significantly faster in recognizing negative words (as compared with baseline) when primed with Russian versus Latvian cultural symbols. Greater identification with Russian culture facilitated this effect. We provide a theoretical discussion of mental processes underlying cultural differences in emotion research.

  3. Comparison of the developmental changes of the brainstem auditory evoked response (BAER) in taurine-supplemented and taurine-deficient kittens.

    Science.gov (United States)

    Vallecalle-Sandoval, M H; Heaney, G; Sersen, E; Sturman, J A

    1991-01-01

    A similar development of the brainstem auditory evoked response is present in taurine-supplemented and taurine-deficient kittens between the second postnatal week and the third month of life. Between birth and the second postnatal week kittens from mothers fed the 1% taurine diet showed earlier maturation of the brainstem auditory evoked response as indicated by lower threshold, shorter P1 latency and shorter central conduction time when compared to the kittens from mothers fed the 0.05% taurine diet. These results suggest an important role of taurine in the anatomical and functional development of the auditory system.

  4. Peripheral Attentional Targets under Covert Attention Lead to Paradoxically Enhanced Alpha Desynchronization in Neurofibromatosis Type 1.

    Directory of Open Access Journals (Sweden)

    Gilberto Silva

    Full Text Available The limited capacity of the human brain to process the full extent of visual information reaching the visual cortex requires the recruitment of mechanisms of information selection through attention. Neurofibromatosis type-1 (NF1 is a neurodevelopmental disease often exhibiting attentional deficits and learning disabilities, and is considered to model similar impairments common in other neurodevelopmental disorders such as autism. In a previous study, we found that patients with NF1 are more prone to miss targets under overt attention conditions. This finding was interpreted as a result of increased occipito-parietal alpha oscillations. In the present study, we used electroencephalography (EEG to study alpha power modulations and the performance of patients with NF1 in a covert attention task. Covert attention was required in order to perceive changes (target offset of a peripherally presented stimulus. Interestingly, alpha oscillations were found to undergo greater desynchronization under this task in the NF1 group compared with control subjects. A similar pattern of desynchronization was found for beta frequencies while no changes in gamma oscillations could be identified. These results are consistent with the notion that different attentional states and task demands generate different patterns of abnormal modulation of alpha oscillatory processes in NF1. Under covert attention conditions and while target offset was reported with relatively high accuracy (over 90% correct responses, excessive desynchronization was found. These findings suggest an abnormal modulation of oscillatory activity and attentional processes in NF1. Given the known role of alpha in modulating attention, we suggest that alpha patterns can show both abnormal increases and decreases that are task and performance dependent, in a way that enhanced alpha desynchronization may reflect a compensatory mechanism to keep performance at normal levels. These results suggest that

  5. Peripheral Attentional Targets under Covert Attention Lead to Paradoxically Enhanced Alpha Desynchronization in Neurofibromatosis Type 1.

    Science.gov (United States)

    Silva, Gilberto; Ribeiro, Maria J; Costa, Gabriel N; Violante, Inês; Ramos, Fabiana; Saraiva, Jorge; Castelo-Branco, Miguel

    2016-01-01

    The limited capacity of the human brain to process the full extent of visual information reaching the visual cortex requires the recruitment of mechanisms of information selection through attention. Neurofibromatosis type-1 (NF1) is a neurodevelopmental disease often exhibiting attentional deficits and learning disabilities, and is considered to model similar impairments common in other neurodevelopmental disorders such as autism. In a previous study, we found that patients with NF1 are more prone to miss targets under overt attention conditions. This finding was interpreted as a result of increased occipito-parietal alpha oscillations. In the present study, we used electroencephalography (EEG) to study alpha power modulations and the performance of patients with NF1 in a covert attention task. Covert attention was required in order to perceive changes (target offset) of a peripherally presented stimulus. Interestingly, alpha oscillations were found to undergo greater desynchronization under this task in the NF1 group compared with control subjects. A similar pattern of desynchronization was found for beta frequencies while no changes in gamma oscillations could be identified. These results are consistent with the notion that different attentional states and task demands generate different patterns of abnormal modulation of alpha oscillatory processes in NF1. Under covert attention conditions and while target offset was reported with relatively high accuracy (over 90% correct responses), excessive desynchronization was found. These findings suggest an abnormal modulation of oscillatory activity and attentional processes in NF1. Given the known role of alpha in modulating attention, we suggest that alpha patterns can show both abnormal increases and decreases that are task and performance dependent, in a way that enhanced alpha desynchronization may reflect a compensatory mechanism to keep performance at normal levels. These results suggest that dysregulation of

  6. The effect of a concurrent cognitive task on cortical potentials evoked by unpredictable balance perturbations

    Directory of Open Access Journals (Sweden)

    Staines W Richard

    2004-05-01

    Full Text Available Abstract Background Although previous studies suggest that postural control requires attention and other cognitive resources, the central mechanisms responsible for this relationship remain unclear. To address this issue, we examined the effects of altered attention on cortical activity and postural responses following mechanical perturbations to upright stance. We hypothesized that cortical activity would be attenuated but not delayed when mechanical perturbations were applied during a concurrent performance of a cognitive task (i.e. when attention was directed away from the perturbation. We also hypothesized that these cortical changes would be accompanied by alterations in the postural response, as evidenced by increases in the magnitude of anteroposterior (AP centre of pressure (COP peak displacements and tibialis anterior (TA muscle activity. Healthy young adults (n = 7 were instructed to continuously track (cognitive task or not track (control task a randomly moving visual target using a hand-held joystick. During each of these conditions, unpredictable translations of a moving floor evoked cortical and postural responses. Scalp-recorded cortical activity, COP, and TA electromyographic (EMG measures were collected. Results Results revealed a significant decrease in the magnitude of early cortical activity (the N1 response, the first negative peak after perturbation onset during the tracking task compared to the control condition. More pronounced AP COP peak displacements and EMG magnitudes were also observed for the tracking task and were possibly related to changes in the N1 response. Conclusion Based on previous notions that the N1 response represents sensory processing of the balance disturbance, we suggest that the attenuation of the N1 response is an important central mechanism that may provide insight into the relationship between attention and postural control.

  7. Attentional enhancement via selection and pooling of early sensory responses in human visual cortex.

    Science.gov (United States)

    Pestilli, Franco; Carrasco, Marisa; Heeger, David J; Gardner, Justin L

    2011-12-08

    The computational processes by which attention improves behavioral performance were characterized by measuring visual cortical activity with functional magnetic resonance imaging as humans performed a contrast-discrimination task with focal and distributed attention. Focal attention yielded robust improvements in behavioral performance accompanied by increases in cortical responses. Quantitative analysis revealed that if performance were limited only by the sensitivity of the measured sensory signals, the improvements in behavioral performance would have corresponded to an unrealistically large reduction in response variability. Instead, behavioral performance was well characterized by a pooling and selection process for which the largest sensory responses, those most strongly modulated by attention, dominated the perceptual decision. This characterization predicts that high-contrast distracters that evoke large responses should negatively impact behavioral performance. We tested and confirmed this prediction. We conclude that attention enhanced behavioral performance predominantly by enabling efficient selection of the behaviorally relevant sensory signals.

  8. Attention deficit hyperactivity disorder (ADHD)

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001551.htm Attention deficit hyperactivity disorder To use the sharing features on this page, please enable JavaScript. Attention deficit hyperactivity disorder (ADHD) is a problem caused by the presence ...

  9. Simultaneously-evoked auditory potentials (SEAP): A new method for concurrent measurement of cortical and subcortical auditory-evoked activity.

    Science.gov (United States)

    Slugocki, Christopher; Bosnyak, Daniel; Trainor, Laurel J

    2017-03-01

    Recent electrophysiological work has evinced a capacity for plasticity in subcortical auditory nuclei in human listeners. Similar plastic effects have been measured in cortically-generated auditory potentials but it is unclear how the two interact. Here we present Simultaneously-Evoked Auditory Potentials (SEAP), a method designed to concurrently elicit electrophysiological brain potentials from inferior colliculus, thalamus, and primary and secondary auditory cortices. Twenty-six normal-hearing adult subjects (mean 19.26 years, 9 male) were exposed to 2400 monaural (right-ear) presentations of a specially-designed stimulus which consisted of a pure-tone carrier (500 or 600 Hz) that had been amplitude-modulated at the sum of 37 and 81 Hz (depth 100%). Presentation followed an oddball paradigm wherein the pure-tone carrier was set to 500 Hz for 85% of presentations and pseudo-randomly changed to 600 Hz for the remaining 15% of presentations. Single-channel electroencephalographic data were recorded from each subject using a vertical montage referenced to the right earlobe. We show that SEAP elicits a 500 Hz frequency-following response (FFR; generated in inferior colliculus), 80 (subcortical) and 40 (primary auditory cortex) Hz auditory steady-state responses (ASSRs), mismatch negativity (MMN) and P3a (when there is an occasional change in carrier frequency; secondary auditory cortex) in addition to the obligatory N1-P2 complex (secondary auditory cortex). Analyses showed that subcortical and cortical processes are linked as (i) the latency of the FFR predicts the phase delay of the 40 Hz steady-state response, (ii) the phase delays of the 40 and 80 Hz steady-state responses are correlated, and (iii) the fidelity of the FFR predicts the latency of the N1 component. The SEAP method offers a new approach for measuring the dynamic encoding of acoustic features at multiple levels of the auditory pathway. As such, SEAP is a promising tool with which to study how

  10. Formation and reverberation of sequential neural activity patterns evoked by sensory stimulation are enhanced during cortical desynchronization.

    Science.gov (United States)

    Bermudez Contreras, Edgar J; Schjetnan, Andrea Gomez Palacio; Muhammad, Arif; Bartho, Peter; McNaughton, Bruce L; Kolb, Bryan; Gruber, Aaron J; Luczak, Artur

    2013-08-07

    Memory formation is hypothesized to involve the generation of event-specific neural activity patterns during learning and the subsequent spontaneous reactivation of these patterns. Here, we present evidence that these processes can also be observed in urethane-anesthetized rats and are enhanced by desynchronized brain state evoked by tail pinch, subcortical carbachol infusion, or systemic amphetamine administration. During desynchronization, we found that repeated tactile or auditory stimulation evoked unique sequential patterns of neural firing in somatosensory and auditory cortex and that these patterns then reoccurred during subsequent spontaneous activity, similar to what we have observed in awake animals. Furthermore, the formation of these patterns was blocked by an NMDA receptor antagonist, suggesting that the phenomenon depends on synaptic plasticity. These results suggest that anesthetized animals with a desynchronized brain state could serve as a convenient model for studying stimulus-induced plasticity to improve our understanding of memory formation and replay in the brain.

  11. Does the capsaicin-sensitive local neural circuit constitutively regulate vagally evoked esophageal striated muscle contraction in rats?

    Science.gov (United States)

    Shima, Takeshi; Shiina, Takahiko; Naitou, Kiyotada; Nakamori, Hiroyuki; Sano, Yuuki; Shimizu, Yasutake

    2016-03-01

    To determine whether a capsaicin-sensitive local neural circuit constitutively modulates vagal neuromuscular transmission in the esophageal striated muscle or whether the neural circuit operates in a stimulus-dependent manner, we compared the motility of esophageal preparations isolated from intact rats with those in which capsaicin-sensitive neurons had been destroyed. Electrical stimulation of the vagus nerve trunk evoked contractile responses in the esophagus isolated from a capsaicin-treated rat in a manner similar to those in the esophagus from a control rat. No obvious differences were observed in the inhibitory effects of D-tubocurarine on intact and capsaicin-treated rat esophageal motility. Destruction of the capsaicin-sensitive neurons did not significantly affect latency, time to peak and duration of a vagally evoked twitch-like contraction. These findings indicate that the capsaicin-sensitive neural circuit does not operate constitutively but rather is activated in response to an applied stimulus.

  12. Chewing and Attention: A Positive Effect on Sustained Attention

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Hirano

    2015-01-01

    Full Text Available Chewing is crushing food not only to aid swallowing and digestion, but also to help stress relief and regulate cognitive function, especially in attention. It is well known that chewing gum is used for sleepiness prevention during work, learning, and driving, suggesting a link between chewing and sustained attention. We hypothesized that chewing elevates attention and/or alertness, leading to improvements in cognitive performance. We carried out a systematic review of the PubMed database. We inspected the attributes of effects on attention in studies investigating the effects of chewing on attention or alertness conducted with pre-post design in healthy subjects, except elderly. We identified 151 references, 22 of which were included: 14 (64% showed positive attributes of effects on attention, 1 (5% showed negative attributes of effects on attention, 5 (23% showed both positive and negative attributes of effects on attention, and 2 (9% showed no significant attributes of effects on attention. Thus, positive attributes of effects of chewing on attention, especially on sustained attention, were shown in over half of the reports. These effects also appeared with improvement in mood and stress relief and were influenced by time-on-task effect. Further studies are needed, but chewing could be useful for modifying cognitive function.

  13. Chewing and attention: a positive effect on sustained attention.

    Science.gov (United States)

    Hirano, Yoshiyuki; Onozuka, Minoru

    2015-01-01

    Chewing is crushing food not only to aid swallowing and digestion, but also to help stress relief and regulate cognitive function, especially in attention. It is well known that chewing gum is used for sleepiness prevention during work, learning, and driving, suggesting a link between chewing and sustained attention. We hypothesized that chewing elevates attention and/or alertness, leading to improvements in cognitive performance. We carried out a systematic review of the PubMed database. We inspected the attributes of effects on attention in studies investigating the effects of chewing on attention or alertness conducted with pre-post design in healthy subjects, except elderly. We identified 151 references, 22 of which were included: 14 (64%) showed positive attributes of effects on attention, 1 (5%) showed negative attributes of effects on attention, 5 (23%) showed both positive and negative attributes of effects on attention, and 2 (9%) showed no significant attributes of effects on attention. Thus, positive attributes of effects of chewing on attention, especially on sustained attention, were shown in over half of the reports. These effects also appeared with improvement in mood and stress relief and were influenced by time-on-task effect. Further studies are needed, but chewing could be useful for modifying cognitive function.

  14. An inventory and update of jealousy-evoking partner behaviours in modern society.

    NARCIS (Netherlands)

    Dijkstra, Pieternel; Barelds, Dick P. H.; Groothof, Hinke A. K.

    2010-01-01

    The goal of the present study was to identify the most important jealousy-evoking partner behaviours and to examine the extent to which these behaviours evoke jealousy. Based on the literature, a questionnaire was constructed containing 42 jealousy-evoking partner behaviours, including a partner's e

  15. Assessment of attention in preschoolers.

    Science.gov (United States)

    Mahone, E M; Schneider, H E

    2012-12-01

    In the past two decades, there has been an increased interest in the assessment and treatment of preschool children presenting with concerns about attention problems. This article reviews the research and clinical literature involving assessment of attention and related skills in the preschool years. While inattention among preschoolers is common, symptoms alone do not necessarily indicate a disorder, and most often represent a normal variation in typical preschool child development. Thus, accurate identification of "disordered" attention in preschoolers can be challenging, and development of appropriate, norm-referenced tests of attention for preschoolers is also difficult. The current review suggests that comprehensive assessment of attention and related functions in the preschool child should include thorough review of the child's history, planned observations, and formal psychometric testing. The three primary methods of psychometric assessment that have been used to characterize attentional functioning in preschool children include performance-based tests, structured caregiver interviews, and rating scales (parent, teacher, and clinician). Among performance-based methods for measurement of attention in the preschool years, tests have been developed to assess sustained attention, selective (focused) attention, span of attention (encoding/manipulation), and (top-down) controlled attention--including freedom from distractibility and set shifting. Many of these tests remain experimental in nature, and review of published methods yields relatively few commercially available, nationally normed tests of attention for preschoolers, and an overall dearth of reliability and validity studies on the available measures.

  16. Intrinsic and task-evoked network architectures of the human brain

    Science.gov (United States)

    Cole, Michael W.; Bassett, Danielle S.; Power, Jonathan D.; Braver, Todd S.; Petersen, Steven E.

    2014-01-01

    Summary Many functional network properties of the human brain have been identified during rest and task states, yet it remains unclear how the two relate. We identified a whole-brain network architecture present across dozens of task states that was highly similar to the resting-state network architecture. The most frequent functional connectivity strengths across tasks closely matched the strengths observed at rest, suggesting this is an “intrinsic”, standard architecture of functional brain organization. Further, a set of small but consistent changes common across tasks suggests the existence of a task-general network architecture distinguishing task states from rest. These results indicate the brain’s functional network architecture during task performance is shaped primarily by an intrinsic network architecture that is also present during rest, and secondarily by evoked task-general and task-specific network changes. This establishes a strong relationship between resting-state functional connectivity and task-evoked functional connectivity – areas of neuroscientific inquiry typically considered separately. PMID:24991964

  17. The effect of Jujuboside A on the evoked field potentials of Granule cells in dentate gyrus

    Institute of Scientific and Technical Information of China (English)

    封洲燕; 郑筱祥

    2002-01-01

    Jujuboside A( JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus.The authors have not seen report on JuA's direct effect on the neruons of the central nervous system.This study aimed to assess the effect of JuA on paried-pulse responses of dentate gyrus granule cells in urethaneanasesthetized rats,used intracerebroventricular(i.c.v.) JuA to mimic in vitro tath conditions in vivo.Pariedpulse stimuli with 80ms interpulse interval were used to stimulate the perforant pathway.Evoked responses first responses,the slopoes of excitatory postsynaptic potential(EPSP1) and the amplitudes of population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly.In the second responses.the EPSP2 slops and PS2 latencies were changed similarly to those of the first ones.but PS2 amplitudes increased.The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N-methyl-D-aspartic mediating paired-pulse facilitation is a postsynaptic mechanism.

  18. Psychosocial stress evoked by a virtual audience: relation to neuroendocrine activity.

    Science.gov (United States)

    Kelly, Owen; Matheson, Kimberly; Martinez, Alejandra; Merali, Zul; Anisman, Hymie

    2007-10-01

    A modified version of the Trier Social Stress Test (TSST) was employed to determine whether exposure to a virtual audience using virtual reality (VR) technology would prompt an increase of neuroendocrine activity comparable to that prompted by a real audience. Following an anticipatory period, participants completed a speech or a speech-plus-math challenge in front of either a virtual audience, a panel of judges they were led to believe was behind a one-way mirror, or an audience comprised of confederates. An additional group that had prepared a speech was simply directed to observe the virtual audience but did not deliver the speech. Finally, a control group completed questionnaires for the duration of the experiment. Cortisol samples were obtained upon arrival to the laboratory, just before the challenge, and 15 and 30 minutes after the task. Participants also completed a measure assessing stressor appraisals of the task before and after the challenge. Anticipation of the task was associated with a modest increase of cortisol levels, and a further rise of cortisol was evident in response to the challenge. The neuroendocrine changes evoked by the virtual audience were comparable to those elicited by the imagined audience (behind the one-way mirror) but less than changes evoked by the panel of confederates. Stressor appraisals were higher post-challenge compared to those reported prior to the task; however, appraisals were similar across each group. These data suggest that VR technology may be amenable to evaluating the impact of psychosocial stressors such as the TSST.

  19. The effect of Jujuboside A on the evoked field potentials of granule cells in dentate gyrus

    Institute of Scientific and Technical Information of China (English)

    封洲燕; 郑筱祥

    2002-01-01

    Jujuboside A (JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus. The authors have not seen any report on JuA's direct effect on the neurons of the central nervous system. This study aimed to assess the effect of JuA on paired-pulse responses of dentate gyrus granule cells in urethane-anaesthetized rats, used intracerebroventricular (i.c.v.) JuA to mimic in vitro bath conditions in vivo. Paired-pulse stimuli with 80ms interpulse interval were used to stimulate the perforant pathway. Evoked responses were recorded in the dentate gyrus cell layer after i.c.v. administration of 0.9% normal saline or JuA. In the first responses, the slopes of excitatory postsynaptic potential (EPSP1) and the amplitudes of population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly. In the second responses, the EPSP2 slopes and PS2 latencies were changed similarly to those of the first ones, but PS2 amplitudes increased. The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N-methyl-D-aspartic mediating paired-pulse facilitation is a postsynaptic mechanism.

  20. The stimulus-evoked population response in visual cortex of awake monkey is a propagating wave.

    Science.gov (United States)

    Muller, Lyle; Reynaud, Alexandre; Chavane, Frédéric; Destexhe, Alain

    2014-04-28

    Propagating waves occur in many excitable media and were recently found in neural systems from retina to neocortex. While propagating waves are clearly present under anaesthesia, whether they also appear during awake and conscious states remains unclear. One possibility is that these waves are systematically missed in trial-averaged data, due to variability. Here we present a method for detecting propagating waves in noisy multichannel recordings. Applying this method to single-trial voltage-sensitive dye imaging data, we show that the stimulus-evoked population response in primary visual cortex of the awake monkey propagates as a travelling wave, with consistent dynamics across trials. A network model suggests that this reliability is the hallmark of the horizontal fibre network of superficial cortical layers. Propagating waves with similar properties occur independently in secondary visual cortex, but maintain precise phase relations with the waves in primary visual cortex. These results show that, in response to a visual stimulus, propagating waves are systematically evoked in several visual areas, generating a consistent spatiotemporal frame for further neuronal interactions.

  1. Evidence for evoked release of adenosine and glutamate from cultured cerebellar granule cells

    Energy Technology Data Exchange (ETDEWEB)

    Schousboe, A.; Frandsen, A.; Drejer, J. (Univ. of Copenhagen (Denmark))

    1989-09-01

    Evoked release of ({sup 3}H)-D-aspartate which labels the neurotransmitter glutamate pool in cultured cerebellar granule cells was compared with evoked release of adenosine from similar cultures. It was found that both adenosine and (3H)-D-aspartate could be released from the neurons in a calcium dependent manner after depolarization of the cells with either 10-100 microM glutamate or 50 mM KCl. Cultures of cerebellar granule cells treated with 50 microM kainate to eliminate GABAergic neurons behaved in the same way. This together with the observation that cultured astrocytes did not exhibit a calcium dependent, potassium stimulated adenosine release strongly suggest that cerebellar granule cells release adenosine in a neurotransmitter-like fashion together with glutamate which is the classical neurotransmitter of these neurons. Studies of the metabolism of adenosine showed that in the granule cells adenosine is rapidly metabolized to ATP, ADP, and AMP, but in spite of this, adenosine was found to be released preferential to ATP.

  2. A COMPARISON OF SEMANTIC SIMILARITY MODELS IN EVALUATING CONCEPT SIMILARITY

    Directory of Open Access Journals (Sweden)

    Q. X. Xu

    2012-08-01

    Full Text Available The semantic similarities are important in concept definition, recognition, categorization, interpretation, and integration. Many semantic similarity models have been established to evaluate semantic similarities of objects or/and concepts. To find out the suitability and performance of different models in evaluating concept similarities, we make a comparison of four main types of models in this paper: the geometric model, the feature model, the network model, and the transformational model. Fundamental principles and main characteristics of these models are introduced and compared firstly. Land use and land cover concepts of NLCD92 are employed as examples in the case study. The results demonstrate that correlations between these models are very high for a possible reason that all these models are designed to simulate the similarity judgement of human mind.

  3. a Comparison of Semantic Similarity Models in Evaluating Concept Similarity

    Science.gov (United States)

    Xu, Q. X.; Shi, W. Z.

    2012-08-01

    The semantic similarities are important in concept definition, recognition, categorization, interpretation, and integration. Many semantic similarity models have been established to evaluate semantic similarities of objects or/and concepts. To find out the suitability and performance of different models in evaluating concept similarities, we make a comparison of four main types of models in this paper: the geometric model, the feature model, the network model, and the transformational model. Fundamental principles and main characteristics of these models are introduced and compared firstly. Land use and land cover concepts of NLCD92 are employed as examples in the case study. The results demonstrate that correlations between these models are very high for a possible reason that all these models are designed to simulate the similarity judgement of human mind.

  4. Attachment style moderates partner presence effects on pain: a laser-evoked potentials study.

    Science.gov (United States)

    Krahé, Charlotte; Paloyelis, Yannis; Condon, Heather; Jenkinson, Paul M; Williams, Steven C R; Fotopoulou, Aikaterini

    2015-08-01

    Social support is crucial for psychological and physical well-being. Yet, in experimental and clinical pain research, the presence of others has been found to both attenuate and intensify pain. To investigate the factors underlying these mixed effects, we administered noxious laser stimuli to 39 healthy women while their romantic partner was present or absent, and measured pain ratings and laser-evoked potentials (LEPs) to assess the effects of partner presence on subjective pain experience and underlying neural processes. Further, we examined whether individual differences in adult attachment style (AAS), alone or in interaction with the partner's level of attentional focus (manipulated to be either on or away from the participant) might modulate these effects. We found that the effects of partner presence vs absence on pain-related measures depended on AAS but not partner attentional focus. The higher participants' attachment avoidance, the higher pain ratings and N2 and P2 local peak amplitudes were in the presence compared with the absence of the romantic partner. As LEPs are thought to reflect activity relating to the salience of events, our data suggest that partner presence may influence the perceived salience of events threatening the body, particularly in individuals who tend to mistrust others.

  5. Attentional Lapses of Adults with Attention Deficit Hyperactivity Disorder in Tasks of Sustained Attention

    NARCIS (Netherlands)

    Gmehlin, Dennis; Fuermaier, Anselm B.M.; Walther, Stephan; Tucha, Lara; Koerts, Janneke; Lange, Klaus W.; Tucha, Oliver; Weisbrod, Matthias; Aschenbrenner, Steffen

    2016-01-01

    Adults with attention deficit hyperactivity disorder (ADHD) show attentional dysfunction such as distractibility and mind-wandering, especially in lengthy tasks. However, fundamentals of dysfunction are ambiguous and relationships of neuropsychological test parameters with self-report measures of AD

  6. A Unified Model of Attention and Problem Solving.

    Science.gov (United States)

    1984-02-01

    paradigma deocribed boro. In confliot condition. In a facolitation condition GREEN Stroup sitnations signls are preented simultaneously o would be plinted In...and perforlao. paradigma similar to theae studied .. . .. ’ Attention and Problem solInS Page 65 Attention and Problem Solving Page 66 her.. Mis

  7. Temperamental and Joint Attentional Predictors of Language Development

    Science.gov (United States)

    Salley, Brenda J.; Dixon, Wallace E., Jr.

    2007-01-01

    Individual differences in child temperament have been associated with individual differences in language development. Similarly, relationships have been reported between early nonverbal social communication (joint attention) and both temperament and language. The present study examined whether individual differences in joint attention might…

  8. [Attention deficit hyperactivity disorder].

    Science.gov (United States)

    Cunill, Ruth; Castells, Xavier

    2015-04-20

    Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood psychiatric disorders and can persist into the adulthood. ADHD has important social, academic and occupational consequences. ADHD diagnosis is based on the fulfillment of several clinical criteria, which can vary depending on the diagnostic system used. The clinical presentation can show great between-patient variability and it has been related to a dysfunction in the fronto-striatal and meso-limbic circuits. Recent investigations support a model in which multiple genetic and environmental factors interact to create a neurobiological susceptibility to develop the disorder. However, no clear causal association has yet been identified. Although multimodal treatment including both pharmacological and psychosocial interventions is usually recommended, no convincing evidence exists to support this recommendation. Pharmacological treatment has fundamentally shown to improve ADHD symptoms in the short term, while efficacy data for psychosocial interventions are scarce and inconsistent. Yet, drug treatment is increasingly popular and the last 2 decades have witnessed a sharp increase in the prescription of anti-ADHD medications coinciding with the marketing of new drugs to treat ADHD.

  9. Attention Networks and Consciousness

    Directory of Open Access Journals (Sweden)

    Michael ePosner

    2012-03-01

    Full Text Available The term consciousness is an important one in the vernacular of the western literature in many fields. It is no wonder that scientists have assumed that consciousness will be found as a component of the human brain and that we will come to understand its neural basis. However, there is rather little in common between consciousness as the neurologist would use it to diagnose the vegetative state, how the feminist would use it to support raising male consciousness of the economic plight of women and as the philosopher would use it when defining the really hard question of the subjective state of awareness induced by sensory qualities. When faced with this kind of problem it is usual to subdivide the term into more manageable perhaps partly operational definitions. Three meanings that capture aspects of consciousness are: (1 the neurology of the state of mind allowing coherent orientation to time and place (2 the selection of sensory or memorial information for awareness and (3 the voluntary control over overt responses. In each of these cases the mechanisms of consciousness overlap with one or more of the attentional networks that have been studied with the methods of cognitive neuroscience. In this paper we explore t

  10. Visual evoked potentials in a patient with prosopagnosia.

    Science.gov (United States)

    Small, M

    1988-01-01

    Visual evoked potentials (VEPs) were recorded from a 53-year-old man with prosopagnosia during presentation of slides of known and unknown faces and under two control conditions. ANOVA comparisons with a normal male group showed no differences in P100 amplitude, P300 amplitude or P300 latency. There were no significant evoked potential differences between the patient and controls specifically related to the face conditions. There was, however, a significant delay in the latency of P100 from both hemispheres during all types of stimuli. This prolonged latency was asymmetrical, showing a right sided emphasis with the control conditions: pattern reversal and slides of geometric designs. This finding, of a dissociation in the interhemispheric delay, provides physiological evidence of stimulus-specific organisation at an early, sensory level. The fact that the P100 component showed a marked delay, yet P300 fell within normal limits for amplitude and latency, suggests that this patient's problem lies at a perceptual level.

  11. Short latency vestibular evoked potentials in the chicken embryo

    Science.gov (United States)

    Jones, S. M.; Jones, T. A.

    1996-01-01

    Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

  12. Evoked potentials and head injury. 2. Clinical applications.

    Science.gov (United States)

    Rappaport, M; Hopkins, H K; Hall, K; Belleza, T

    1981-10-01

    The method of rating abnormality of evoked brain potential patterns and assessing the extent and severity of cortical and subcortical brain dysfunction in head injury patients described in Part I is applied in a clinical context. Evoked potential abnormality (EPA) scores are found to be significantly correlated both with admission and outcome disability approximately one year after head injury. Correlations increase with the increase in the number of sensory modalities tested. Correlations between EPA scores and clinical disability (measured by the Disability Rating Scale) decrease with time after injury. Significant correlations, however, persist for about 60 days after onset of injury. It was found that EP pattern abnormalities can reflect specific sensory (and at times motor) deficits in noncommunicative patients and thereby contribute significantly to early treatment and rehabilitation planning.

  13. Evoked response audiometry used in testing auditory organs of miners

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, T.; Klepacki, J.; Wagstyl, R.

    1980-01-01

    The evoked response audiometry method of testing hearing loss is presented and the results of comparative studies using subjective tonal audiometry and evoked response audiometry in tests of 56 healthy men with good hearing are discussed. The men were divided into three groups according to age and place of work: work place without increased noise; work place with noise and vibrations (at drilling machines); work place with noise and shocks (work at excavators in surface coal mines). The ERA-MKII audiometer produced by the Medelec-Amplaid firm was used. Audiometric threshhold curves for the three groups of tested men are given. At frequencies of 500, 1000 and 4000 Hz mean objective auditory threshhold was shifted by 4-9.5 dB in comparison to the subjective auditory threshold. (21 refs.) (In Polish)

  14. [Long-latency auditory evoked potentials in cochlear implants].

    Science.gov (United States)

    Mata, J J; Jiménez, J M; Pérez, J; Postigo, A; Roldán, B

    1999-01-01

    Cortical evoked potentials were evaluated in patients with cochlear implants. In a group of 8 adults of different ages, the lingual state before implantation and during rehabilitation were evaluated. Using cortical evoked potentials, the results of the P300 wave in response to two tones, one frequent (1,000 Hz) and the other infrequent (2,000 Hz), presented at 70 and 80 dB HL were studied. Results were analyzed and compared in relation to locutive state, rehabilitation stage, and intensity of stimulus. Absolute latencies did not differ significantly. However, latency values in relation to reaction time were significantly longer in prelingual than in postlingual patients (p test). The results confirmed the normality of central cognitive processes in patients with cochlear implants in objective assessment of P300 latency. The results suggest differences between prelingual and postlingual patients in relation to central signal processing.

  15. Ritual relieved axial dystonia triggered by gaze-evoked amaurosis.

    Science.gov (United States)

    Jacome, D E

    1997-11-01

    A woman with chronic posttraumatic axial lateropulsion cervical dystonia ("belly dancer's head") found relief of her spontaneous dystonic spasms by the sequential performance of an elaborate motor ritual. During an episode of left optic papillitis caused by central retinal vein occlusion, gaze-evoked amaurosis of the left eye developed, preceded by achromatopsia, during left lateral gaze. Gaze-evoked amaurosis triggered axial dystonia, which was followed by her unique, stereotyped, dystonia-relieving ritual that simulated a slow dance. Visual symptoms improved progressively in 1 year. Eventually, she was unable to trigger her dystonia by eye movements. Spontaneous dystonia remained otherwise unchanged from before the episode of papillitis and was still relieved by her unique ritual.

  16. Application of transient evoked otoacoustic emissions to pediatric populations.

    Science.gov (United States)

    Norton, S J

    1993-02-01

    Transient evoked otoacoustic emissions (TEOAEs) occur after presentation of brief acoustic stimuli such as clicks and tone pips. They represent physiological activity from within the cochlea, specifically from normal functioning outer hair cells. TEOAEs are frequency specific in that their spectra are determined by the spectra of the evoking stimulus and the audiometric configuration. TEOAEs are sensitive to mild to moderate degrees of cochlear hearing loss up to about 40 to 50 dB HL. They can be measured rapidly and noninvasively in infants and children. Among the potential applications in pediatric audiology are screening for hearing impairment in neonates, separating peripheral hearing loss and central auditory dysfunction, and monitoring cochlear status in children receiving ototoxic drugs.

  17. Similarity Learning of Manifold Data.

    Science.gov (United States)

    Chen, Si-Bao; Ding, Chris H Q; Luo, Bin

    2015-09-01

    Without constructing adjacency graph for neighborhood, we propose a method to learn similarity among sample points of manifold in Laplacian embedding (LE) based on adding constraints of linear reconstruction and least absolute shrinkage and selection operator type minimization. Two algorithms and corresponding analyses are presented to learn similarity for mix-signed and nonnegative data respectively. The similarity learning method is further extended to kernel spaces. The experiments on both synthetic and real world benchmark data sets demonstrate that the proposed LE with new similarity has better visualization and achieves higher accuracy in classification.

  18. MAOA Influences the Trajectory of Attentional Development

    Science.gov (United States)

    Lundwall, Rebecca A.; Rasmussen, Claudia G.

    2016-01-01

    Attention is vital to success in all aspects of life (Meck and Benson, 2002; Erickson et al., 2015), hence it is important to identify biomarkers of later attentional problems early enough to intervene. Our objective was to determine if any of 11 genes (APOE, BDNF, HTR4, CHRNA4, COMT, DRD4, IGF2, MAOA, SLC5A7, SLC6A3, and SNAP25) predicted the trajectory of attentional development within the same group of children between infancy and childhood. We recruited follow up participants from children who participated as infants in visual attention studies and used a similar task at both time points. Using multilevel modeling, we associated changes in the participant’s position in the distribution of scores in infancy to his/her position in childhood with genetic markers on each of 11 genes. While all 11 genes predicted reaction time (RT) residual scores, only Monoamine oxidase A (MAOA) had a significant interaction including time point. We conclude that the MAOA single nucleotide polymorphism (SNP) rs1137070 is useful in predicting which girls are likely to develop slower RTs on an attention task between infancy and childhood. This early identification is likely to be helpful in early intervention. PMID:27610078

  19. Two-stage processing of sounds explains behavioral performance variations due to changes in stimulus contrast and selective attention: an MEG study.

    Directory of Open Access Journals (Sweden)

    Jaakko Kauramäki

    Full Text Available Selectively attending to task-relevant sounds whilst ignoring background noise is one of the most amazing feats performed by the human brain. Here, we studied the underlying neural mechanisms by recording magnetoencephalographic (MEG responses of 14 healthy human subjects while they performed a near-threshold auditory discrimination task vs. a visual control task of similar difficulty. The auditory stimuli consisted of notch-filtered continuous noise masker sounds, and of 1020-Hz target tones occasionally (p = 0.1 replacing 1000-Hz standard tones of 300-ms duration that were embedded at the center of the notches, the widths of which were parametrically varied. As a control for masker effects, tone-evoked responses were additionally recorded without masker sound. Selective attention to tones significantly increased the amplitude of the onset M100 response at ~100 ms to the standard tones during presence of the masker sounds especially with notches narrower than the critical band. Further, attention modulated sustained response most clearly at 300-400 ms time range from sound onset, with narrower notches than in case of the M100, thus selectively reducing the masker-induced suppression of the tone-evoked response. Our results show evidence of a multiple-stage filtering mechanism of sensory input in the human auditory cortex: 1 one at early (~100 ms latencies bilaterally in posterior parts of the secondary auditory areas, and 2 adaptive filtering of attended sounds from task-irrelevant background masker at longer latency (~300 ms in more medial auditory cortical regions, predominantly in the left hemisphere, enhancing processing of near-threshold sounds.

  20. Attention in a bayesian framework

    DEFF Research Database (Denmark)

    Whiteley, Louise Emma; Sahani, Maneesh

    2012-01-01

    The behavioral phenomena of sensory attention are thought to reflect the allocation of a limited processing resource, but there is little consensus on the nature of the resource or why it should be limited. Here we argue that a fundamental bottleneck emerges naturally within Bayesian models...... of perception, and use this observation to frame a new computational account of the need for, and action of, attention - unifying diverse attentional phenomena in a way that goes beyond previous inferential, probabilistic and Bayesian models. Attentional effects are most evident in cluttered environments......, and include both selective phenomena, where attention is invoked by cues that point to particular stimuli, and integrative phenomena, where attention is invoked dynamically by endogenous processing. However, most previous Bayesian accounts of attention have focused on describing relatively simple experimental...

  1. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates and models temporal suppression of click-evoked otoacoustic emissions (CEOAEs). This suppression-effect is created when a suppressor-click is presented close in time to a test-click. The analysis was carried out for short time-frames of short- and long-latency CEOAEs. The ...... phenomenologically using compression or expansion of the system output. This was obtained by shifting the operating-point on the input-output-characteristic in relation to the ICI....

  2. Cerebral oxygen delivery and consumption during evoked neural activity

    Directory of Open Access Journals (Sweden)

    Alberto L Vazquez

    2010-06-01

    Full Text Available Increases in neural activity evoke increases in the delivery and consumption of oxygen. Beyond observations of cerebral tissue and blood oxygen, the role and properties of cerebral oxygen delivery and consumption during changes in brain function are not well understood. This work overviews the current knowledge of functional oxygen delivery and consumption and introduces recent and preliminary findings to explore the mechanisms by which oxygen is delivered to tissue as well as the temporal dynamics of oxygen metabolism. Vascular oxygen tension measurements have shown that a relatively large amount of oxygen exits pial arterioles prior to capillaries. Additionally, increases in cerebral blood flow (CBF induced by evoked neural activation are accompanied by arterial vasodilation and also by increases in arteriolar oxygenation. This increase contributes not only to the down-stream delivery of oxygen to tissue, but also to delivery of additional oxygen to extra-vascular spaces surrounding the arterioles. On the other hand, the changes in tissue oxygen tension due to functional increases in oxygen consumption have been investigated using a method to suppress the evoked CBF response. The functional decreases in tissue oxygen tension induced by increases in oxygen consumption are slow to evoked changes in CBF under control conditions. Preliminary findings obtained using flavoprotein autofluorescence imaging suggest cellular oxidative metabolism changes at a faster rate than the average changes in tissue oxygen. These issues are important in the determination of the dynamic changes in tissue oxygen metabolism from hemoglobin-based imaging techniques such as blood oxygenation-level dependent functional magnetic resonance imaging (fMRI.

  3. [Visual evoked potentials (VEP) in anesthesia and intensive care].

    Science.gov (United States)

    Russ, W; Krumholz, W; Hempelmann, G

    1984-03-01

    Methodological considerations and different stimulation techniques of visual evoked potentials (VEP) are described. VEP can provide information about neurological function during anaesthesia, surgery and in the unconscious patient after head injury. The feasibility of the method for intraoperative monitoring in neuro- and cardiac surgery and the influence of general anaesthetics and other contributing factors such as temperature, paCO2, pO2, part are discussed.

  4. Brain stem auditory evoked responses in chronic alcoholics.

    OpenAIRE

    Chan, Y W; McLeod, J G; Tuck, R R; Feary, P A

    1985-01-01

    Brain stem auditory evoked responses (BAERs) were performed on 25 alcoholic patients with Wernicke-Korsakoff syndrome, 56 alcoholic patients without Wernicke-Korsakoff syndrome, 24 of whom had cerebellar ataxia, and 37 control subjects. Abnormal BAERs were found in 48% of patients with Wernicke-Korsakoff syndrome, in 25% of alcoholic patients without Wernicke-Korsakoff syndrome but with cerebellar ataxia, and in 13% of alcoholic patients without Wernicke-Korsakoff syndrome or ataxia. The mean...

  5. Pattern shift visual evoked response: application in neurology

    Directory of Open Access Journals (Sweden)

    Carlos A. M. Guerreiro

    1982-03-01

    Full Text Available The technique that we use for pattern shift visual evoked response (PSVER is described. PSVER is a non-invasive, practical and reliable clinical test in detecting anterior visual pathways lesions even when asymptomatic. The ability to find unsuspected lesions in multiple sclerosis, making possible an early diagnosis, is underscored. We also discuss some pathophysiologic aspects and the findings of the PSVER in some neurologic disorders with visual system involvement.

  6. Large margin classification with indefinite similarities

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2016-01-07

    Classification with indefinite similarities has attracted attention in the machine learning community. This is partly due to the fact that many similarity functions that arise in practice are not symmetric positive semidefinite, i.e. the Mercer condition is not satisfied, or the Mercer condition is difficult to verify. Examples of such indefinite similarities in machine learning applications are ample including, for instance, the BLAST similarity score between protein sequences, human-judged similarities between concepts and words, and the tangent distance or the shape matching distance in computer vision. Nevertheless, previous works on classification with indefinite similarities are not fully satisfactory. They have either introduced sources of inconsistency in handling past and future examples using kernel approximation, settled for local-minimum solutions using non-convex optimization, or produced non-sparse solutions by learning in Krein spaces. Despite the large volume of research devoted to this subject lately, we demonstrate in this paper how an old idea, namely the 1-norm support vector machine (SVM) proposed more than 15 years ago, has several advantages over more recent work. In particular, the 1-norm SVM method is conceptually simpler, which makes it easier to implement and maintain. It is competitive, if not superior to, all other methods in terms of predictive accuracy. Moreover, it produces solutions that are often sparser than more recent methods by several orders of magnitude. In addition, we provide various theoretical justifications by relating 1-norm SVM to well-established learning algorithms such as neural networks, SVM, and nearest neighbor classifiers. Finally, we conduct a thorough experimental evaluation, which reveals that the evidence in favor of 1-norm SVM is statistically significant.

  7. Average is Boring: How Similarity Kills a Meme's Success

    Science.gov (United States)

    Coscia, Michele

    2014-09-01

    Every day we are exposed to different ideas, or memes, competing with each other for our attention. Previous research explained popularity and persistence heterogeneity of memes by assuming them in competition for limited attention resources, distributed in a heterogeneous social network. Little has been said about what characteristics make a specific meme more likely to be successful. We propose a similarity-based explanation: memes with higher similarity to other memes have a significant disadvantage in their potential popularity. We employ a meme similarity measure based on semantic text analysis and computer vision to prove that a meme is more likely to be successful and to thrive if its characteristics make it unique. Our results show that indeed successful memes are located in the periphery of the meme similarity space and that our similarity measure is a promising predictor of a meme success.

  8. STUDY ON EVOKED POTENTIALS IN TYPE 2 DIABETIC PATIENTS

    Institute of Scientific and Technical Information of China (English)

    陈薇; 陈慎仁; 陈璇; 吴静珊; 刘兴材

    2003-01-01

    The aim of this study is to explore the changes of visual evoked potentiaK VEP), brainstem auditory evoked potential (BAEP), Somatosensory e-voked potential (SEP), event-related potential(ERP) of patients with type 2 diabetes mellitus(DM).Methods VEP, BAEP, SEP, ERP were measured in 30 cases with type 2 DM (DM group) and in 30 age- and sex-matched healthy volunteers (Control group) by using Nicolet Viking Ⅳ EMG/EP instrument. The numerical values of VEP, BAEP, SEP and ERP were recorded and analyzed by SPSS.Results Abnormalities were found as follows: VEP in 20(66.7%), BAEP in 18(60%), MNSEP in 20(66.7%),PTNSEP in 22(73.3%), and ERP in 11 (36.67%) diabetic patients, including the disappearance of wave, prolonged wave latency and decreased wave amplitude. Compared with control group, the P100 latency of VEP, the latencies of wave Ⅰ and Ⅴ, amplitude of wave Ⅴ, the interpeak latencies (IPL) of each wave in BAEP, the latencies and wave amplitudes in N9 to P20 of MNSEP and in N9 to P38 of PTNSEP, as well a

  9. Brainstem auditory evoked potential abnormalities in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Sharat Gupta

    2013-01-01

    Full Text Available Background: Diabetes mellitus represents a syndrome complex in which multiple organ systems, including the central nervous system, are affected. Aim: The study was conducted to determine the changes in the brainstem auditory evoked potentials in type 2 diabetes mellitus. Materials and Methods: A cross sectional study was conducted on 126 diabetic males, aged 35-50 years, and 106 age-matched, healthy male volunteers. Brainstem auditory evoked potentials were recorded and the results were analyzed statistically using student′s unpaired t-test. The data consisted of wave latencies I, II, III, IV, V and interpeak latencies I-III, III-V and I-V, separately for both ears. Results: The latency of wave IV was significantly delayed only in the right ear, while the latency of waves III, V and interpeak latencies III-V, I-V showed a significant delay bilaterally in diabetic males. However, no significant difference was found between diabetic and control subjects as regards to the latency of wave IV unilaterally in the left ear and the latencies of waves I, II and interpeak latency I-III bilaterally. Conclusion: Diabetes patients have an early involvement of central auditory pathway, which can be detected with fair accuracy with auditory evoked potential studies.

  10. Evoked otoacoustic emissions in workers exposed to noise: A review

    Directory of Open Access Journals (Sweden)

    Alcarás, Patrícia Arruda de Souza

    2012-01-01

    Full Text Available Introduction: The otoacoustic emissions test is an essential tool in the evaluation of auditory function, since it allows the early detection of cochlear damage of occupational origin. Objective: To present a review of the literature and analyze the effectiveness of the clinical application of the otoacoustic emissions test in workers exposed to noise. Methods: A bibliographical search covering a period of 10 years was performed in the Virtual Health Library including published articles in national and international journals indexed in the internationally recognized databases for the health sciences, LILACS, SCIELO, and MEDLINE, using the terms "otoacoustic emissions" and "occupational exposure." The type of published article (national/international, the type and intensity of the stimulus most commonly used for the evoked otoacoustic emissions, the gender and age of the subjects, and the conclusions from the retrospective studies were all taken into consideration. Results and Conclusions: A total of 19 articles were analyzed, 7 national and 12 international, covering subjects from 17 to 77 years of age, mostly men. The type of stimulus most commonly used for the evoked otoacoustic emissions was the distortion method (12. Through this review, we have concluded that testing of evoked otoacoustic emissions in workers exposed to noise is an important tool in the early diagnosis of noise-induced cochlear hearing disorders.

  11. Vestibular-evoked myogenic potentials in miniature pigs

    Institute of Scientific and Technical Information of China (English)

    Xi Shi; Yan Zhang; Ya Li; Shiwei Qiu; Shili Zhang; Yaohan Li; Na Yuan; Yuehua Qiao; Shiming Yang

    2016-01-01

    Objective:To report detection of vestibular-evoked myogenic potentials (VEMPs) in the miniature pig. Methods:Potentials evoked by 1000 Hz tone bursts were recorded from neck extensor muscles and the masseter muscles in normal adult Bama miniature pigs anesthetized with 3%pentobarbital sodium and Carbachol II. Results:The latency of the first positive wave P from neck extensor muscles was 7.65 ± 0.64 ms, with an amplitude of 1.66 ± 0.34 uv and a rate of successful induction of 75%at 80 dB SPL. The latency of potentials evoked from the masseter muscles was 7.60 ± 0.78 ms, with an amplitude of 1.31 ± 0.28 uv and a rate successful induction of 66%at 80 dB SPL. Conclusion:The latencies and thresholds of VEMPs recorded from the neck extensor muscle and the masseter muscle appear to be comparable in normal adult Bama miniature pigs, although the amplitude recorded from the neck extensor muscle seems to be higher than that from the masseter muscle. However, because of their usually relatively superficial and easily accessible location, as well as their large volume and strong contractions, masseter muscles may be better target muscles for recording myogenic potentials.

  12. Brainstem auditory evoked potentials in children with lead exposure

    Directory of Open Access Journals (Sweden)

    Katia de Freitas Alvarenga

    2015-02-01

    Full Text Available Introduction: Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. Objective: To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Methods: Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months. Results: The mean time-integrated cumulative blood lead index was 12 µg/dL (SD ± 5.7, range:2.433. All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. Conclusion: No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area.

  13. Somatosensory evoked magnetic fields in patients with stroke.

    Science.gov (United States)

    Maclin, E L; Rose, D F; Knight, J E; Orrison, W W; Davis, L E

    1994-12-01

    We used magnetoencephalography to evaluate areas of sensory cortex in patients with ischemic strokes involving the somatomotor system. We measured somatosensory evoked magnetic fields using a 7-channel neuromagnetometer and estimated the location of cortical responses to median nerve stimulation in 5 patients with cortical or subcortical strokes involving the somatomotor system. All patients underwent quantitative neurological examinations and a high resolution volumetric magnetic resonance imaging. The estimated current dipoles were localized onto the patient's own MRI scan in all patients with measurable responses. The location of the estimated dipole was always in non-infarcted tissue in the anatomical region of the somatosensory cortex. In 1 patient the somatosensory dipole localized to a peninsula of cortex flanked by infarcted tissue. Single photon emission computed tomography found the localized area of cortex to have significant blood flow. The estimated current dipole strengths of somatosensory evoked fields from median nerve stimulation correlated significantly (r = 0.95, P graphesthesia). The combination of evoked magnetic field recording and magnetic resonance imaging is a promising non-invasive technology for studying brain function in patients with cerebrovascular disease.

  14. Optical suppression of drug-evoked phasic dopamine release.

    Science.gov (United States)

    McCutcheon, James E; Cone, Jackson J; Sinon, Christopher G; Fortin, Samantha M; Kantak, Pranish A; Witten, Ilana B; Deisseroth, Karl; Stuber, Garret D; Roitman, Mitchell F

    2014-01-01

    Brief fluctuations in dopamine concentration (dopamine transients) play a key role in behavior towards rewards, including drugs of abuse. Drug-evoked dopamine transients may result from actions at both dopamine cell bodies and dopamine terminals. Inhibitory opsins can be targeted to dopamine neurons permitting their firing activity to be suppressed. However, as dopamine transients can become uncoupled from firing, it is unknown whether optogenetic hyperpolarization at the level of the soma is able to suppress dopamine transients. Here, we used in vivo fast-scan cyclic voltammetry to record transients evoked by cocaine and raclopride in nucleus accumbens (NAc) of urethane-anesthetized rats. We targeted halorhodopsin (NpHR) specifically to dopamine cells by injecting Cre-inducible virus into ventral tegmental area (VTA) of transgenic rats that expressed Cre recombinase under control of the tyrosine hydroxylase promoter (TH-Cre(+) rats). Consistent with previous work, co-administration of cocaine and raclopride led to the generation of dopamine transients in NAc shell. Illumination of VTA with laser strongly suppressed the frequency of transients in NpHR-expressing rats, but not in control rats. Laser did not have any effect on amplitude of transients. Thus, optogenetics can effectively reduce the occurrence of drug-evoked transients and is therefore a suitable approach for studying the functional role of such transients in drug-associated behavior.

  15. Optical suppression of drug-evoked phasic dopamine release

    Directory of Open Access Journals (Sweden)

    James Edgar Mccutcheon

    2014-09-01

    Full Text Available Brief fluctuations in dopamine concentration (dopamine transients play a key role in behavior towards rewards, including drugs of abuse. Drug-evoked dopamine transients may result from actions at both dopamine cell bodies and dopamine terminals. Inhibitory opsins can be targeted to dopamine neurons permitting their firing activity to be suppressed. However, as dopamine transients can become uncoupled from firing, it is unknown whether optogenetic hyperpolarization at the level of the soma is able to suppress dopamine transients. Here, we used in vivo fast-scan cyclic voltammetry to record transients evoked by cocaine and raclopride in nucleus accumbens (NAc of urethane-anesthetized rats. We targeted halorhodopsin (NpHR specifically to dopamine cells by injecting Cre-inducible virus into ventral tegmental area (VTA of transgenic rats that expressed Cre recombinase under control of the tyrosine hydroxylase promoter (TH-Cre+ rats. Consistent with previous work, co-administration of cocaine and raclopride led to the generation of dopamine transients in NAc shell. Illumination of VTA with laser strongly suppressed the frequency of transients in NpHR-expressing rats, but not in control rats. Laser did not have any effect on amplitude of transients. Thus, optogenetics can effectively reduce the occurrence of drug-evoked transients and is therefore a suitable approach for studying the functional role of such transients in drug-associated behavior.

  16. Components and sequential changes in event-related potential induced by gaze orientation processing under a reflective attention cue paradigm

    Institute of Scientific and Technical Information of China (English)

    Yingdi Li; Xuemin Zhang; Yan Song; Qing Feng

    2010-01-01

    Gaze orientation induces activation of relevant brain regions,presents differences in specificity and time course,and is exhibited in patients with brain injury.However,the components of activated event-related potential remain controversial.Previous studies of behavior and cognitive neuroscience related to gaze orientation investigated conscious attention of visual orientation.The present study explored gaze orientation processing-induced event-related potential components and changes with time using reflective orientation of visual attention under a reflective attention cue paradigm.Visual attention processing of gaze orientation was recorded using event-related potential and electroencephalographic recording.Results demonstrated that the reflective attention cue task evoked early directing attention negativity and anterior directing attention negativity,but did not trigger late directing attention positivity.These results suggest that reflective attention occurs over a short time of visual stimulus presentation.During the early stage of attention processing,early directing attention negativity and anterior directing attention negativity were detected,but late directing attention positivity did not occur.These results confirmed reflectivity and time-course superiority of gaze orientation attention processing.

  17. Unilateral and bilateral brainstem auditory-evoked response abnormalities in 900 Dalmatian dogs.

    Science.gov (United States)

    Holliday, T A; Nelson, H J; Williams, D C; Willits, N

    1992-01-01

    In a survey of 900 Dalmatian dogs, brainstem auditory-evoked responses (BAER) and clinical observations were used to determine the incidence and sex distribution of bilateral and unilateral BAER abnormalities and their association with heterochromia iridis (HI). To assess the efficacy of BAER testing in guiding breeding programs, data from 749 dogs (subgroup A), considered to be a sample of the population at large, were compared with data from a subgroup (subgroup B; n = 151) in which selection of breeding stock had been based on BAER testing from the beginning of the 4-year survey. Brainstem auditory-evoked responses were elicited by applying click stimuli unilaterally, while applying a white noise masking sound to the contralateral ear. Under these conditions, BAER were either normal, unilaterally absent, or bilaterally absent. Dogs with bilaterally absent BAER were clinically deaf; dogs with unilaterally absent BAER were not clinically deaf but appeared dependent on their BAER-normal ears for their auditory-cued behavior. Dogs with unilaterally absent BAER often were misidentified as normal by uninformed observers. Among the 900 dogs, 648 (72.0%) were normal, 189 (21.0%) had unilateral absence of BAER, and 63 (7.0%) had bilateral absence of BAER or were clinically deaf and assumed to have bilaterally absent BAER (n = 4). Total incidence in the population sampled was assumed to be higher, because some bilaterally affected dogs that would have been members of subgroup A undoubtedly did not come to our attention. Among females, 24.0% were unilaterally abnormal and 8.2% were bilaterally abnormal whereas, among males, 17.8% were unilaterally abnormal and 5.7% were bilaterally abnormal.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Attention-Modulating Effects of Cognitive Enhancers

    Science.gov (United States)

    Attention can be readily measured in experimental animal models. Animal models of attention have been used to better understand the neural systems involved in attention, how attention is impaired, and how therapeutic treatments can ameliorate attentional deficits. This review fo...

  19. Dynamic similarity in erosional processes

    Science.gov (United States)

    Scheidegger, A.E.

    1963-01-01

    A study is made of the dynamic similarity conditions obtaining in a variety of erosional processes. The pertinent equations for each type of process are written in dimensionless form; the similarity conditions can then easily be deduced. The processes treated are: raindrop action, slope evolution and river erosion. ?? 1963 Istituto Geofisico Italiano.

  20. [Autism and attention deficit hyperactivity disorder: similarities and differences in executive functioning and theory of mind].

    Science.gov (United States)

    Miranda-Casas, Ana; Baixauli-Fortea, Immaculada; Colomer-Diago, Carla; Roselló-Miranda, Belén

    2013-09-06

    Introduccion. Aunque los criterios diagnosticos del autismo y del trastorno por deficit de atencion/hiperactividad (TDAH) en el DSM-IV-TR no se solapan, la presencia de sintomas de TDAH en individuos con un diagnostico clinico de autismo es muy elevada. A su vez, los niños con TDAH pueden tener rasgos autistas, aunque los mas prevalentes son las dificultades sociales y de comunicacion. El analisis del perfil en las funciones ejecutivas y en la teoria de la mente (ToM) podria ayudar a explicar el solapamiento y la diferenciacion entre ambos trastornos. Objetivo. Revisar los hallazgos de estudios empiricos en los que se ha comparado a niños con TDAH y con autismo en indicadores de funcionamiento ejecutivo y ToM. Desarrollo. La revision de las investigaciones sugiere la existencia de patrones distintos en el trastorno del espectro autista (TEA) y en el TDAH cuando el funcionamiento ejecutivo se segmenta en componentes. Los niños con TDAH experimentan deficit en el control inhibitorio mientras que los niños con TEA tienen mas problemas en flexibilidad cognitiva y en planificacion. En cuanto al dominio de las habilidades mentales se producen diferencias evolutivas, asi como en su gravedad. Los niños mas pequeños con TEA experimentan mayores deficiencias en la ToM en comparacion con los niños con TDAH y un deficit primario en la orientacion social. Conclusiones. Aunque los avances son importantes, quedan asuntos pendientes por aclarar, entre los que destaca el analisis de como afecta un pobre desarrollo de las funciones ejecutivas al desarrollo de la ToM, con estudios longitudinales que analicen las trayectorias evolutivas de niños con TEA y niños con TDAH.

  1. Prognosis in prolonged coma patients with diffuse axonal injury assessed by somatosensory evoked potential

    Institute of Scientific and Technical Information of China (English)

    Xiujue Zheng; Mantao Chen; Jingqi Li; Fei Cao

    2013-01-01

    A total of 43 prolonged coma patients with diffuse axonal injury received the somatosensory evoked potential examination one month after injury in the First Affiliated Hospital, School of Medicine, Zhejiang University in China. Somatosensory evoked potentials were graded as normal, abnormal or absent (grades I–III) according to N20 amplitude and central conduction time. The outcome in patients with grade III somatosensory evoked potential was in each case unfavorable. The prognostic accuracy of grade III somatosensory evoked potential for unfavorable and non-awakening outcome was 100% and 80%, respectively. The prognostic accuracy of grade I somatosensory evoked potential for favorable and wakening outcome was 86% and 100%, respectively. These results suggest that somatosensory evoked potential grade is closely correlated with coma severity and degree of recovery. Somatosensory evoked potential is a valuable diagnostic tool to assess prognosis in prolonged coma patients with diffuse axonal injury.

  2. Attentional Lapses of Adults with Attention Deficit Hyperactivity Disorder in Tasks of Sustained Attention.

    Science.gov (United States)

    Gmehlin, Dennis; Fuermaier, Anselm B M; Walther, Stephan; Tucha, Lara; Koerts, Janneke; Lange, Klaus W; Tucha, Oliver; Weisbrod, Matthias; Aschenbrenner, Steffen

    2016-06-01

    Adults with attention deficit hyperactivity disorder (ADHD) show attentional dysfunction such as distractibility and mind-wandering, especially in lengthy tasks. However, fundamentals of dysfunction are ambiguous and relationships of neuropsychological test parameters with self-report measures of ADHD symptoms are marginal. We hypothesize that basic deficits in sustaining attention explain more complex attentional dysfunction in persons with ADHD and relate to ADHD symptoms. Attentional function was analyzed by computing ex-Gaussian parameters for 3 time Blocks in a 20 min test of sustained alertness. Changes in performance across these blocks were analyzed by comparing adult persons with ADHD (n = 24) with healthy matched controls (n = 24) and correlated with neuropsychological measures of selective and divided attention as well as self-report measures of ADHD symptoms. We found a significantly steeper increase in the number of slow responses (ex-Gaussian parameter τ) in persons with ADHD with time on task in basic sustained alertness. They also performed significantly worse in tasks of sustained selective and divided attention. However, after controlling for an increase in τ during the alertness task, significant differences between groups disappeared for divided and partly selective attention. Increases in τ in the sustained alertness task correlated significantly with self-report measures of ADHD symptoms. Our results provide evidence that very basic deficits in sustaining attention in adults with ADHD are related to infrequent slow responses (=attentional lapses), with changes over time being relevant for more complex attentional function and experienced ADHD symptoms in everyday life.

  3. Executive and attentional contributions to Theory of Mind deficit in attention deficit/hyperactivity disorder (ADHD).

    Science.gov (United States)

    Mary, Alison; Slama, Hichem; Mousty, Philippe; Massat, Isabelle; Capiau, Tatiana; Drabs, Virginie; Peigneux, Philippe

    2016-01-01

    Attention deficit/hyperactivity disorder (ADHD) in children has been associated with attentional and executive problems, but also with socioemotional difficulties possibly associated with deficits in Theory of Mind (ToM). Socioemotional problems in ADHD are associated with more negative prognoses, notably interpersonal, educational problems, and an increased risk of developing other psychiatric disorders that emphasize the need to clarify the nature of their ToM deficits. In this study, we hypothesized that ToM dysfunction in children with ADHD is largely attributable to their attentional and/or executive deficits. Thirty-one children with ADHD (8-12 years, IQ > 85) and 31 typically developing (TD) children were assessed using executive functions (inhibition, planning, and flexibility) and attentional tasks, as well as two advanced ToM tasks (Reading the Mind in the Eyes and Faux Pas) involving different levels of executive control. Children with ADHD performed more poorly than TD children in attentional, executive function, and ToM tasks. Linear regression analyses conducted in the ADHD group indicated that inhibition scores predicted performance on the "Faux Pas" task the best, while attention scores were the best for predicting performance on the Reading the Mind in the Eyes task. When controlled for inhibition and attentional variables, ToM performance in children with ADHD was actually similar to TD children. Contrarily, controlling for ToM scores did not normalize performance for inhibition and attentional tasks in children with ADHD. This unidirectional relationship suggests that deficits in the EF and attentional domains are responsible for ToM deficits in ADHD, which therefore may contribute to their socioemotional difficulties.

  4. Similarity of samples and trimming

    CERN Document Server

    Álvarez-Esteban, Pedro C; Cuesta-Albertos, Juan A; Matrán, Carlos; 10.3150/11-BEJ351

    2012-01-01

    We say that two probabilities are similar at level $\\alpha$ if they are contaminated versions (up to an $\\alpha$ fraction) of the same common probability. We show how this model is related to minimal distances between sets of trimmed probabilities. Empirical versions turn out to present an overfitting effect in the sense that trimming beyond the similarity level results in trimmed samples that are closer than expected to each other. We show how this can be combined with a bootstrap approach to assess similarity from two data samples.

  5. Habituation of evoked responses is greater in patients with familial hemiplegic migraine than in controls

    DEFF Research Database (Denmark)

    Hansen, Jakob Møller; Bolla, M; Magis, D;

    2011-01-01

    been attributed to neuronal dysexcitability. FHM and the common forms of migraine are thought to belong to a spectrum of migraine phenotypes with similar pathophysiology, and we therefore examined whether an abnormal habituation pattern would also be found in FHM patients.......Familial hemiplegic migraine (FHM) is a rare, dominantly inherited subtype of migraine with transient hemiplegia during the aura phase. Mutations in at least three different genes can produce the FHM phenotype. The mutated FHM genes code for ion transport proteins that animal and cellular studies...... have associated with disturbed ion homeostasis, altered cellular excitability, neurotransmitter release, and decreased threshold for cortical spreading depression. The common forms of migraine are characterized interictally by a habituation deficit of cortical and subcortical evoked responses that has...

  6. Exploring the variability of single trials in somatosensory evoked responses using constrained source extraction and RMT.

    Science.gov (United States)

    Koutras, A; Kostopoulos, G K; Ioannides, A A

    2008-03-01

    This paper describes the theoretical background of a new data-driven approach to encephalographic single-trial (ST) data analysis. Temporal constrained source extraction using sparse decomposition identifies signal topographies that closely match the shape characteristics of a reference signal, one response for each ST. The correlations between these ST topographies are computed for formal Correlation Matrix Analysis (CMA) based on Random Matrix Theory (RMT). The RMT-CMA provides clusters of similar ST topologies in a completely unsupervised manner. These patterns are then classified into deterministic set and noise using well established RMT results. The efficacy of the method is applied to EEG and MEG data of somatosensory evoked responses (SERs). The results demonstrate that the method can recover brain signals with time course resembling the reference signal and follow changes in strength and/or topography in time by simply stepping the reference signal through time.

  7. Cortical evoked potentials in response to rapid balloon distension of the rectum and anal canal

    DEFF Research Database (Denmark)

    Haas, S; Brock, C; Krogh, K;

    2014-01-01

    BACKGROUND: Neurophysiological evaluation of anorectal sensory function is hampered by a paucity of methods. Rapid balloon distension (RBD) has been introduced to describe the cerebral response to rectal distension, but it has not successfully been applied to the anal canal. METHODS: Nineteen...... healthy women received 30 RBDs in the rectum and the anal canal at intensities corresponding to sensory and unpleasantness thresholds, and response was recorded as cortical evoked potentials (CEPs) in 64-channels. The anal canal stimulations at unpleasantness level were repeated after 4 min to test...... the within-day reproducibility. CEPs were averaged, and to overcome latency variation related to jitter the spectral content of single sweeps was also computed. KEY RESULTS: Repeated stimulation of the anal canal generated CEPs with similar latencies but smaller amplitudes compared to those from the rectum...

  8. Effects of carnosine on the evoked potentials in hippocampal CA1 region

    Institute of Scientific and Technical Information of China (English)

    Zhou-yan FENG; Xiao-jing ZHENG; Jing WANG

    2009-01-01

    Objective: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. Methods: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. Results: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of γ-aminobutyric acidA (GABAA) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly.However, no significant change was observed in the spontaneous field potentials during the application of carnosine. Conclusion:The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.

  9. Value of visual evoked potential monitoring during trans-sphenoidal pituitary surgery.

    Science.gov (United States)

    Chacko, A G; Babu, K S; Chandy, M J

    1996-06-01

    The visual outcome of 22 patients undergoing trans-sphenoidal excision of pituitary macroadenomas with intraoperative flash visual evoked potential (VEP) monitoring (Group A), was compared with a non-randomized group of 14 patients who had undergone similar operations without VEP monitoring (Group B). Tumour size, preoperative visual acuity, peripheral fields, and latencies and amplitudes of P1 and P2 were analysed to ascertain the best predictor of postoperative visual function. It was found that patients in Group A had a significantly greater improvement in field defects than those in Group B. There was no difference in postoperative improvement in visual acuity between the two groups. None of the variables analysed were good predictors of visual outcome.

  10. When sustained attention impairs perception

    OpenAIRE

    Ling, Sam; Carrasco, Marisa

    2006-01-01

    Virtually all behavioral and neurophysiological studies have shown that sustained (endogenous, conceptually driven) attention enhances perception. But can this enhancement be held indefinitely? We assessed the time course of attention’s effects on contrast sensitivity, reasoning that if attention does indeed boost stimulus strength, the strengthened representation could result in stronger adaptation over time. We found that attention initially enhances contrast sensitivity, but that over time...

  11. Self-similar aftershock rates

    CERN Document Server

    Davidsen, Jörn

    2016-01-01

    In many important systems exhibiting crackling noise --- intermittent avalanche-like relaxation response with power-law and, thus, self-similar distributed event sizes --- the "laws" for the rate of activity after large events are not consistent with the overall self-similar behavior expected on theoretical grounds. This is in particular true for the case of seismicity and a satisfying solution to this paradox has remained outstanding. Here, we propose a generalized description of the aftershock rates which is both self-similar and consistent with all other known self-similar features. Comparing our theoretical predictions with high resolution earthquake data from Southern California we find excellent agreement, providing in particular clear evidence for a unified description of aftershocks and foreshocks. This may offer an improved way of time-dependent seismic hazard assessment and earthquake forecasting.

  12. Self-similar aftershock rates

    Science.gov (United States)

    Davidsen, Jörn; Baiesi, Marco

    2016-08-01

    In many important systems exhibiting crackling noise—an intermittent avalanchelike relaxation response with power-law and, thus, self-similar distributed event sizes—the "laws" for the rate of activity after large events are not consistent with the overall self-similar behavior expected on theoretical grounds. This is particularly true for the case of seismicity, and a satisfying solution to this paradox has remained outstanding. Here, we propose a generalized description of the aftershock rates which is both self-similar and consistent with all other known self-similar features. Comparing our theoretical predictions with high-resolution earthquake data from Southern California we find excellent agreement, providing particularly clear evidence for a unified description of aftershocks and foreshocks. This may offer an improved framework for time-dependent seismic hazard assessment and earthquake forecasting.

  13. Contextual Bandits with Similarity Information

    CERN Document Server

    Slivkins, Aleksandrs

    2009-01-01

    In a multi-armed bandit (MAB) problem, an online algorithm makes a sequence of choices. In each round it chooses from a time-invariant set of alternatives and receives the payoff associated with this alternative. While the case of small strategy sets is by now well-understood, a lot of recent work has focused on MAB problems with exponentially or infinitely large strategy sets, where one needs to assume extra structure in order to make the problem tractable. In particular, recent literature considered information on similarity between arms. We consider similarity information in the setting of "contextual bandits", a natural extension of the basic MAB problem where before each round an algorithm is given the "context" -- a hint about the payoffs in this round. Contextual bandits are directly motivated by placing advertisements on webpages, one of the crucial problems in sponsored search. A particularly simple way to represent similarity information in the contextual bandit setting is via a "similarity distance...

  14. Similarity measures for protein ensembles

    DEFF Research Database (Denmark)

    Lindorff-Larsen, Kresten; Ferkinghoff-Borg, Jesper

    2009-01-01

    Analyses of similarities and changes in protein conformation can provide important information regarding protein function and evolution. Many scores, including the commonly used root mean square deviation, have therefore been developed to quantify the similarities of different protein conformations...... a synthetic example from molecular dynamics simulations. We then apply the algorithms to revisit the problem of ensemble averaging during structure determination of proteins, and find that an ensemble refinement method is able to recover the correct distribution of conformations better than standard single...

  15. Community Detection by Neighborhood Similarity

    Institute of Scientific and Technical Information of China (English)

    LIU Xu; XIE Zheng; YI Dong-Yun

    2012-01-01

    Detection of the community structure in a network is important for understanding the structure and dynamics of the network.By exploring the neighborhood of vertices,a local similarity metric is proposed,which can be quickly computed.The resulting similarity matrix retains the same support as the adjacency matrix.Based on local similarity,an agglomerative hierarchical clustering algorithm is proposed for community detection.The algorithm is implemented by an efficient max-heap data structure and runs in nearly linear time,thus is capable of dealing with large sparse networks with tens of thousands of nodes.Experiments on synthesized and real-world networks demonstrate that our method is efficient to detect community structures,and the proposed metric is the most suitable one among all the tested similarity indices.%Detection of the community structure in a network is important for understanding the structure and dynamics of the network. By exploring the neighborhood of vertices, a local similarity metric is proposed, which can be quickly computed. The resulting similarity matrix retains the same support as the adjacency matrix. Based on local similarity, an agglomerative hierarchical clustering algorithm is proposed for community detection. The algorithm is implemented by an efficient max-heap data structure and runs in nearly linear time, thus is capable of dealing with large sparse networks with tens of thousands of nodes. Experiments on synthesized and real-world networks demonstrate that our method is efficient to detect community structures, and the proposed metric is the most suitable one among all the tested similarity indices.

  16. Limited Attention and Discourse Structure

    CERN Document Server

    Walker, M A

    1995-01-01

    This squib examines the role of limited attention in a theory of discourse structure and proposes a model of attentional state that relates current hierarchical theories of discourse structure to empirical evidence about human discourse processing capabilities. First, I present examples that are not predicted by Grosz and Sidner's stack model of attentional state. Then I consider an alternative model of attentional state, the cache model, which accounts for the examples, and which makes particular processing predictions. Finally I suggest a number of ways that future research could distinguish the predictions of the cache model and the stack model.

  17. Attentional networks in developmental dyscalculia

    Directory of Open Access Journals (Sweden)

    Henik Avishai

    2010-01-01

    Full Text Available Abstract Background Very little is known about attention deficits in developmental dyscalculia, hence, this study was designed to provide the missing information. We examined attention abilities of participants suffering from developmental dyscalculia using the attention networks test - interactions. This test was designed to examine three different attention networks--executive function, orienting and alerting--and the interactions between them. Methods Fourteen university students that were diagnosed as suffering from developmental dyscalculia--intelligence and reading abilities in the normal range and no indication of attention-deficit hyperactivity disorder--and 14 matched controls were tested using the attention networks test - interactions. All participants were given preliminary tests to measure mathematical abilities, reading, attention and intelligence. Results The results revealed deficits in the alerting network--a larger alerting effect--and in the executive function networks--a larger congruity effect in developmental dyscalculia participants. The interaction between the alerting and executive function networks was also modulated by group. In addition, developmental dyscalculia participants were slower to respond in the non-cued conditions. Conclusions These results imply specific attentional deficits in pure developmental dyscalculia. Namely, those with developmental dyscalculia seem to be deficient in the executive function and alertness networks. They suffer from difficulty in recruiting attention, in addition to the deficits in numerical processing.

  18. Capture of exogenous attention modulates the attentional blink

    DEFF Research Database (Denmark)

    Nielsen, Simon; Andersen, Tobias

    2011-01-01

    T1 processing time, this should cause a greater AB. Attention capture hypotheses suggest that T1 captures attention, which cannot be reallocated to T2 in time. Accordingly, if increasing T1 difficulty, decreases saliency, this should cause a smaller AB. Studies examining how T1 difficulty affects...

  19. Characterization of evoked tactile sensation in forearm amputees with transcutaneous electrical nerve stimulation

    Science.gov (United States)

    Chai, Guohong; Sui, Xiaohong; Li, Si; He, Longwen; Lan, Ning

    2015-12-01

    Objective. The goal of this study is to characterize the phenomenon of evoked tactile sensation (ETS) on the stump skin of forearm amputees using transcutaneous electrical nerve stimulation (TENS). Approach. We identified the projected finger map (PFM) of ETS on the stump skin in 11 forearm amputees, and compared perceptual attributes of the ETS in nine forearm amputees and eight able-bodied subjects using TENS. The profile of perceptual thresholds at the most sensitive points (MSPs) in each finger-projected area was obtained by modulating current amplitude, pulse width, and frequency of the biphasic, rectangular current stimulus. The long-term stability of the PFM and the perceptual threshold of the ETS were monitored in five forearm amputees for a period of 11 months. Main results. Five finger-specific projection areas can be independently identified on the stump skin of forearm amputees with a relatively long residual stump length. The shape of the PFM was progressively similar to that of the hand with more distal amputation. Similar sensory modalities of touch, pressure, buzz, vibration, and numb below pain sensation could be evoked both in the PFM of the stump skin of amputees and in the normal skin of able-bodied subjects. Sensory thresholds in the normal skin of able-bodied subjects were generally lower than those in the stump skin of forearm amputees, however, both were linearly modulated by current amplitude and pulse width. The variation of the MSPs in the PFM was confined to a small elliptical area with 95% confidence. The perceptual thresholds of thumb-projected areas were found to vary less than 0.99 × 10-2 mA cm-2. Significance. The stable PFM and sensory thresholds of ETS are desirable for a non-invasive neural interface that can feed back finger-specific tactile information from the prosthetic hand to forearm amputees.

  20. Population response propagation to extrastriate areas evoked by intracortical electrical stimulation in V1

    Directory of Open Access Journals (Sweden)

    Tamas David Fehervari

    2016-02-01

    Full Text Available The mouse visual system has multiple extrastriate areas surrounding V1 each with a distinct representation of the visual field and unique functional and connectivity profiles, which are believed to form two parallel processing streams, similar to the ventral and dorsal streams in primates. At the same time, mouse visual areas have a high degree of interconnectivity, in particular V1 sends input to all higher visual areas. The study of these direct connections can further our understanding of the cortical processing of visual signals in the early mammalian cortex. Several studies have been published about the anatomy of these connections, but an in vivo electrophysiological characterization and comparison of the transmission to multiple extrastriate areas has not yet been reported. We used intracortical electrical stimulation combined with RH1691 VSD imaging in adult C57BL/6 mice in urethane anesthesia to analyze interareal transmission from V1 to extrastriate areas in superficial cortical layers. We found 7 extrastriate response sites (5 lateral, 2 medial in a spatial pattern similar to area maps of the mouse visual cortex and, by shifting the location of V1 stimulation, demonstrated that the evoked responses in LM and AL were in accordance with the visuotopic mappings of these areas known from anatomy and in vivo studies. These two sites, considered to be gateways to their processing streams, had shorter latencies and faster transmission speeds than other extrastriate response sites. Short latency differences between response sites, and that TTX injection into LM reduced but did not eliminate other extrastriate responses indicated that the evoked cortical activity was, at least partially, transmitted directly from V1 to extrastriate areas. This study reports on analysis of interareal transmission from V1 to multiple extrastriate areas in mouse using intracortical electrical stimulation in vivo.

  1. Mindfulness training affects attention--or is it attentional effort?

    DEFF Research Database (Denmark)

    Jensen, Christian Gaden; Vangkilde, Signe Allerup; Frokjaer, Vibe

    2012-01-01

    and visual working memory capacity. Furthermore, stress-reducing effects of MBSR were supported because those in the MBSR group showed significantly less perceived and physiological stress while increasing their mindfulness levels significantly. We argue that MBSR may contribute uniquely to attentional......Improvements in attentional performance are at the core of proposed mechanisms for stress reduction in mindfulness meditation practices. However, this claim can be questioned because no previous studies have actively manipulated test effort in control groups and controlled for effects of stress......, the latter receiving a financial reward to improve attentional performance. Pre- and postintervention, 5 validated attention paradigms were employed along with self-report scales on mindfulness and perceived stress and saliva cortisol samples to measure physiological stress. Attentional effects of MBSR, NMSR...

  2. Real-time monitoring of electrically evoked catecholamine signals in the songbird striatum using in vivo fast-scan cyclic voltammetry.

    Science.gov (United States)

    Smith, Amanda R; Garris, Paul A; Casto, Joseph M

    2015-01-01

    Fast-scan cyclic voltammetry is a powerful technique for monitoring rapid changes in extracellular neurotransmitter levels in the brain. In vivo fast-scan cyclic voltammetry has been used extensively in mammalian models to characterize dopamine signals in both anesthetized and awake preparations, but has yet to be applied to a non-mammalian vertebrate. The goal of this study was to establish in vivo fast-scan cyclic voltammetry in a songbird, the European starling, to facilitate real-time measurements of extracellular catecholamine levels in the avian striatum. In urethane-anesthetized starlings, changes in catecholamine levels were evoked by electrical stimulation of the ventral tegmental area and measured at carbon-fiber microelectrodes positioned in the medial and lateral striata. Catecholamines were elicited by different stimulations, including trains related to phasic dopamine signaling in the rat, and were analyzed to quantify presynaptic mechanisms governing exocytotic release and neuronal uptake. Evoked extracellular catecholamine dynamics, maximal amplitude of the evoked catecholamine signal, and parameters for catecholamine release and uptake did not differ between striatal regions and were similar to those determined for dopamine in the rat dorsomedial striatum under similar conditions. Chemical identification of measured catecholamine by its voltammogram was consistent with the presence of both dopamine and norepinephrine in striatal tissue content. However, the high ratio of dopamine to norepinephrine in tissue content and the greater sensitivity of the carbon-fiber microelectrode to dopamine compared to norepinephrine favored the measurement of dopamine. Thus, converging evidence suggests that dopamine was the predominate analyte of the electrically evoked catecholamine signal measured in the striatum by fast-scan cyclic voltammetry. Overall, comparisons between the characteristics of these evoked signals suggested a similar presynaptic regulation of

  3. Neural evidence reveals the rapid effects of reward history on selective attention.

    Science.gov (United States)

    MacLean, Mary H; Giesbrecht, Barry

    2015-05-05

    Selective attention is often framed as being primarily driven by two factors: task-relevance and physical salience. However, factors like selection and reward history, which are neither currently task-relevant nor physically salient, can reliably and persistently influence visual selective attention. The current study investigated the nature of the persistent effects of irrelevant, physically non-salient, reward-associated features. These features affected one of the earliest reliable neural indicators of visual selective attention in humans, the P1 event-related potential, measured one week after the reward associations were learned. However, the effects of reward history were moderated by current task demands. The modulation of visually evoked activity supports the hypothesis that reward history influences the innate salience of reward associated features, such that even when no longer relevant, nor physically salient, these features have a rapid, persistent, and robust effect on early visual selective attention.

  4. Common mechanisms of spatial attention in memory and perception: a tactile dual-task study.

    Science.gov (United States)

    Katus, Tobias; Andersen, Søren K; Müller, Matthias M

    2014-03-01

    Orienting attention to locations in mnemonic representations engages processes that functionally and anatomically overlap the neural circuitry guiding prospective shifts of spatial attention. The attention-based rehearsal account predicts that the requirement to withdraw attention from a memorized location impairs memory accuracy. In a dual-task study, we simultaneously presented retro-cues and pre-cues to guide spatial attention in short-term memory (STM) and perception, respectively. The spatial direction of each cue was independent of the other. The locations indicated by the combined cues could be compatible (same hand) or incompatible (opposite hands). Incompatible directional cues decreased lateralized activity in brain potentials evoked by visual cues, indicating interference in the generation of prospective attention shifts. The detection of external stimuli at the prospectively cued location was impaired when the memorized location was part of the perceptually ignored hand. The disruption of attention-based rehearsal by means of incompatible pre-cues reduced memory accuracy and affected encoding of tactile test stimuli at the retrospectively cued hand. These findings highlight the functional significance of spatial attention for spatial STM. The bidirectional interactions between both tasks demonstrate that spatial attention is a shared neural resource of a capacity-limited system that regulates information processing in internal and external stimulus representations.

  5. Visual attention: The past 25 years

    OpenAIRE

    Carrasco, Marisa

    2011-01-01

    This review focuses on covert attention and how it alters early vision. I explain why attention is considered a selective process, the constructs of covert attention, spatial endogenous and exogenous attention, and feature-based attention. I explain how in the last 25 years research on attention has characterized the effects of covert attention on spatial filters and how attention influences the selection of stimuli of interest. This review includes the effects of spatial attention on discrim...

  6. Similarity of atoms in molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cioslowski, J.; Nanayakkara, A. (Florida State Univ., Tallahassee, FL (United States))

    1993-12-01

    Similarity of atoms in molecules is quantitatively assessed with a measure that employs electron densities within respective atomic basins. This atomic similarity measure does not rely on arbitrary assumptions concerning basis functions or 'atomic orbitals', is relatively inexpensive to compute, and has straightforward interpretation. Inspection of similarities between pairs of carbon, hydrogen, and fluorine atoms in the CH[sub 4], CH[sub 3]F, CH[sub 2]F[sub 2], CHF[sub 3], CF[sub 4], C[sub 2]H[sub 2], C[sub 2]H[sub 4], and C[sub 2]H[sub 6] molecules, calculated at the MP2/6-311G[sup **] level of theory, reveals that the atomic similarity is greatly reduced by a change in the number or the character of ligands (i.e. the atoms with nuclei linked through bond paths to the nucleus of the atom in question). On the other hand, atoms with formally identical (i.e. having the same nuclei and numbers of ligands) ligands resemble each other to a large degree, with the similarity indices greater than 0.95 for hydrogens and 0.99 for non-hydrogens. 19 refs., 6 tabs.

  7. Similarity measures for face recognition

    CERN Document Server

    Vezzetti, Enrico

    2015-01-01

    Face recognition has several applications, including security, such as (authentication and identification of device users and criminal suspects), and in medicine (corrective surgery and diagnosis). Facial recognition programs rely on algorithms that can compare and compute the similarity between two sets of images. This eBook explains some of the similarity measures used in facial recognition systems in a single volume. Readers will learn about various measures including Minkowski distances, Mahalanobis distances, Hansdorff distances, cosine-based distances, among other methods. The book also summarizes errors that may occur in face recognition methods. Computer scientists "facing face" and looking to select and test different methods of computing similarities will benefit from this book. The book is also useful tool for students undertaking computer vision courses.

  8. Visuospatial selective attention in chickens.

    Science.gov (United States)

    Sridharan, Devarajan; Ramamurthy, Deepa L; Schwarz, Jason S; Knudsen, Eric I

    2014-05-13

    Voluntary control of attention promotes intelligent, adaptive behaviors by enabling the selective processing of information that is most relevant for making decisions. Despite extensive research on attention in primates, the capacity for selective attention in nonprimate species has never been quantified. Here we demonstrate selective attention in chickens by applying protocols that have been used to characterize visual spatial attention in primates. Chickens were trained to localize and report the vertical position of a target in the presence of task-relevant distracters. A spatial cue, the location of which varied across individual trials, indicated the horizontal, but not vertical, position of the upcoming target. Spatial cueing improved localization performance: accuracy (d') increased and reaction times decreased in a space-specific manner. Distracters severely impaired perceptual performance, and this impairment was greatly reduced by spatial cueing. Signal detection analysis with an "indecision" model demonstrated that spatial cueing significantly increased choice certainty in localizing targets. By contrast, error-aversion certainty (certainty of not making an error) remained essentially constant across cueing protocols, target contrasts, and individuals. The results show that chickens shift spatial attention rapidly and dynamically, following principles of stimulus selection that closely parallel those documented in primates. The findings suggest that the mechanisms that control attention have been conserved through evolution, and establish chickens--a highly visual species that is easily trained and amenable to cutting-edge experimental technologies--as an attractive model for linking behavior to neural mechanisms of selective attention.

  9. Caffeine Modulates Attention Network Function

    Science.gov (United States)

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Taylor, Holly A.

    2010-01-01

    The present work investigated the effects of caffeine (0 mg, 100 mg, 200 mg, 400 mg) on a flanker task designed to test Posner's three visual attention network functions: alerting, orienting, and executive control [Posner, M. I. (2004). "Cognitive neuroscience of attention". New York, NY: Guilford Press]. In a placebo-controlled, double-blind…

  10. Computational Attention for Event Detection

    OpenAIRE

    Mancas, Matei; Couvreur, Laurent; Gosselin, Bernard; Macq, Benoît

    2007-01-01

    This article deals with a biologically-motivated three-level computational attention model architecture based on the rarity and the information theory framework. It mainly focuses on low-level and medium-level steps and their application in pre-attentive detection of tumours in CT scans and unusual events in audio recordings.

  11. Cortical modulation of short-latency TMS-evoked potentials

    Directory of Open Access Journals (Sweden)

    Domenica eVeniero

    2013-01-01

    Full Text Available Transcranial magnetic stimulation - electroencephalogram (TMS-EEG co-registration offers the opportunity to test reactivity of brain areas across distinct conditions through TMS-evoked potentials (TEPs. Several TEPs have been described, their functional meaning being largely unknown. In particular, short-latency potentials peaking at 5 (P5 and 8 (N8 ms after the TMS pulse have been recently described, but because of their huge amplitude, the problem of whether their origin is cortical or not has been opened. To gain information about these components, we employed a protocol that modulates primary motor cortex excitability (MI through an exclusively cortical phenomena: low frequency stimulation of premotor area (PMC. TMS was applied simultaneously with EEG recording from 70 electrodes. Amplitude of TEPs evoked by 200 single-pulses TMS delivered over MI at 110% of resting motor threshold was measured before and after applying 900 TMS conditioning stimuli to left premotor cortex with 1 Hz repetition rate. Single subject analyses showed reduction in TEPs amplitude after PMC conditioning in a sample of participants and increase in TEPs amplitude in two subjects. No effects were found on corticospinal excitability as recorded by motor evoked potentials (MEPs. Furthermore, correlation analysis showed an inverse relation between the effects of the conditioning protocol on P5-N8 complex amplitude and MEPs amplitude. Because the effects of the used protocol have been ascribed to a cortical interaction between premotor area and MI, we suggest that despite the sign of P5-N8 amplitude modulation is not consistent across participant, this modulation could indicate, at least in part, their cortical origin. We conclude that with an accurate experimental procedure early-latency components can be used to evaluate the reactivity of the stimulated cortex.

  12. Localizing evoked and induced responses to faces using magnetoencephalography.

    Science.gov (United States)

    Perry, Gavin; Singh, Krish D

    2014-05-01

    A rich pattern of responses in frequency, time and space are known to be generated in the visual cortex in response to faces. Recently, a number of studies have used magnetoencephalography (MEG) to try to record these responses non-invasively - in many cases using source analysis techniques based on the beamforming method. Here we sought both to characterize best practice for measuring face-specific responses using MEG beamforming, and to determine whether the results produced by the beamformer match evidence from other modalities. We measured activity to visual presentation of face stimuli and phase-scrambled control stimuli, and performed source analyses of both induced and evoked responses using Synthetic Aperture Magnetometry. We localized the gamma-band response to bilateral lateral occipital cortex, and both the gamma-band response and the M170-evoked response to the right fusiform gyrus. Differences in the gamma-band response between faces and scrambled stimuli were confined to the frequency range 50-90 Hz; gamma-band activity at higher frequencies did not differ between the two stimulus categories. We additionally identified a component of the M220-evoked response - localized to the parieto-occipital sulcus - which was enhanced for scrambled vs. unscrambled faces. These findings help to establish that MEG beamforming can localize face-specific responses in time, frequency and space with good accuracy (when validated against established findings from functional magnetic resonance imaging and intracranial recordings), as well as contributing to the establishment of best methodological practice for the use of the beamformer method to measure face-specific responses.

  13. What Attracts Decision Makers' Attention?

    DEFF Research Database (Denmark)

    Bentzen, Eric; Christiansen, John K.; Varnes, Claus J.

    2011-01-01

    that might explain decision makers' attention are identified. The analysis shows that the quality of information was not significant for explaining variations of decision makers' attention; but, even more surprisingly, differences in project status did not explain variations in attention. Delayed projects...... did not get significantly more attention than those delivered on time. By controlling for other project characteristics, the newness of projects to the corporate portfolio was found to be the most important parameter. Originality/value – First, the analysis is based on observations from actual...... meetings rather than from surveys. Second, several observations contradict prior research on product development, e.g. it has been argued that decision makers should pay special attention to certain phases and projects having trouble meeting expectations towards planned deadlines. It is also new...

  14. Guiding Attention by Cooperative Cues

    Institute of Scientific and Technical Information of China (English)

    KangWoo Lee

    2008-01-01

    A common assumption in visual attention is based on the rationale of "limited capacity of information pro-ceasing". From this view point there is little consideration of how different information channels or modules are cooperating because cells in processing stages are forced to compete for the limited resource. To examine the mechanism behind the cooperative behavior of information channels, a computational model of selective attention is implemented based on two hypotheses. Unlike the traditional view of visual attention, the cooperative behavior is assumed to be a dynamic integration process between the bottom-up and top-down information. Furthermore, top-down information is assumed to provide a contextual cue during selection process and to guide the attentional allocation among many bottom-up candidates. The result from a series of simulation with still and video images showed some interesting properties that could not be explained by the competitive aspect of selective attention alone.

  15. Faking attention deficit hyperactivity disorder.

    Science.gov (United States)

    Sansone, Randy A; Sansone, Lori A

    2011-08-01

    Attention-deficit hyperactivity disorder is a common malady in the general population, with up to 8.1 percent of adults meeting criteria for this syndrome. In the college setting, the diagnosis of attention deficit hyperactivity disorder may offer specific academic advantages. Once the diagnosis is assigned, the prescription of stimulant medication may provide additional secondary gains through misuse and/or diversion. For example, these drugs may be used by college consumers to increase alertness, energy, academic performance, and athletic performance. Stimulants may also decrease psychological distress, alleviate restlessness and weight concerns, and be used for recreational purposes. According to the findings of five studies, the symptoms of attention deficit hyperactivity disorder can be believably faked, particularly when assessed with attention deficit hyperactivity disorder symptom checklists. Thus, the faking of attention deficit hyperactivity disorder is a realistic concern in both psychiatric and primary care settings.

  16. Brain stem auditory evoked responses in human infants and adults

    Science.gov (United States)

    Hecox, K.; Galambos, R.

    1974-01-01

    Brain stem evoked potentials were recorded by conventional scalp electrodes in infants (3 weeks to 3 years of age) and adults. The latency of one of the major response components (wave V) is shown to be a function both of click intensity and the age of the subject; this latency at a given signal strength shortens postnatally to reach the adult value (about 6 msec) by 12 to 18 months of age. The demonstrated reliability and limited variability of these brain stem electrophysiological responses provide the basis for an optimistic estimate of their usefulness as an objective method for assessing hearing in infants and adults.

  17. Sense Estimation and Instrumental Evaluation of Fabric-Evoked Prickle

    Institute of Scientific and Technical Information of China (English)

    敖利民; 郁崇文

    2004-01-01

    In this paper, the mechanism of fabric-evoked prickle is discussed, which indicates that the mechanical stimuli aroused by the fiber ends on the fabric surface to the skin-sensory receptors are responsible for prickle. The factors influencing the intensity of prickle are specialized and anatomized. Several means of sense estimate, including the corresponding statistical measures, are described. A few groping objective methods of evaluating prickle are analyzed, including the testing principles, the advantages and the disadvantages. At last, a new concept is proposed on the objective evaluation of prickle.

  18. Visual evoked potentials in children prenatally exposed to methylmercury

    DEFF Research Database (Denmark)

    Yorifuji, Takashi; Murata, Katsuyuki; Bjerve, Kristian S

    2013-01-01

    the effect of prenatal methylmercury exposure on visual evoked potential (VEP) latencies in Faroese children with elevated prenatal methylmercury exposure. A cohort of 182 singleton term births was assembled in the Faroe Islands during 1994-1995. At age 7 years, VEP tracings were obtained from 139 cohort...... subjects after exclusion of subjects with abnormal vision conditions. We used multiple regression analysis to evaluate the association of mercury concentrations in cord blood and maternal hair at parturition with VEP latencies after adjustment for potential confounders that included the cord...

  19. Intraoperative Monitoring: Recent Advances in Motor Evoked Potentials.

    Science.gov (United States)

    Koht, Antoun; Sloan, Tod B

    2016-09-01

    Advances in electrophysiological monitoring have improved the ability of surgeons to make decisions and minimize the risks of complications during surgery and interventional procedures when the central nervous system (CNS) is at risk. Individual techniques have become important for identifying or mapping the location and pathway of critical neural structures. These techniques are also used to monitor the progress of procedures to augment surgical and physiologic management so as to reduce the risk of CNS injury. Advances in motor evoked potentials have facilitated mapping and monitoring of the motor tracts in newer, more complex procedures.

  20. Combining segmentation and attention: a new foveal attention model

    Directory of Open Access Journals (Sweden)

    Rebeca eMarfil

    2014-08-01

    Full Text Available Artificial vision systems cannot process all the information that they receive from the world in real time because it is highly expensive and inefficient in terms of computational cost. Inspired by biological perception systems, articial attention models pursuit to select only the relevant part of the scene. Besides, it is well established that the units of attention on human vision are not merely spatial but closely related to perceptual objects (proto-objects. This implies a strong bidirectional relationship between segmentation and attention processes. Therefore, while the segmentation process is the responsible to extract the proto-objects from the scene, attention can guide segmentation, arising the concept of foveal attention. When the focus of attention is deployed from one visual unit to another, the rest of the scene is perceived but at a lower resolution that the focused object. The result is a multi-resolution visual perception in which the fovea, a dimple on the central retina, provides the highest resolution vision. In this paper, a bottom-up foveal attention model is presented. In this model the input image is a foveal image represented using a Cartesian Foveal Geometry (CFG, which encodes the field of view of the sensor as a fovea (placed in the focus of attention surrounded by a set of concentric rings with decreasing resolution. Then multirresolution perceptual segmentation is performed by building a foveal polygon using the Bounded Irregular Pyramid (BIP. Bottom-up attention is enclosed in the same structure, allowing to set the fovea over the most salient image proto-object. Saliency is computed as a linear combination of multiple low level features such us colour and intensity contrast, symmetry, orientation and roundness. Obtained results from natural images show that the performance of the combination of hierarchical foveal segmentation and saliency estimation is good in terms of accuracy and speed.

  1. Collicular dysfunction in attention deficit hyperactivity disorder.

    Science.gov (United States)

    Overton, Paul G

    2008-01-01

    Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder characterised by (inter alia) an increase in distractibility. The current front-line pharmacotherapies for the treatment of ADHD, namely the psychostimulants methylphenidate and amphetamines, have clear abuse potential, hence there is a strong need to develop new drug treatments for this disorder. Central to this process is the identification of the pathophysiological changes which underlie ADHD. Given the heterogeneity of the disorder, multiple loci are probably involved, providing multiple potential therapeutic targets. Here, we hypothesise (Hypothesis 1) that one such locus is the superior colliculus (SC), a sensory structure intimately linked with distractibility and the production of eye and head movements. It is proposed that in ADHD, the colliculus is hyper-responsive, leading to the core symptom of increased distractibility. Hypothesis 1 is supported by: 1. ADHD patients show increased distractibility in tasks which are sensitive to collicular function; 2. ADHD patients have a general problem inhibiting saccades, the generation of which involves the SC; 3. Saccadic deficits in ADHD include defects in the production of saccadic types (anti-saccades and express saccades) which are particularly associated with the colliculus; 4. Covert shifts in attention (which also have been argued to involve the SC) are also impaired in ADHD; 5. Reading disorders are frequently co-morbid with ADHD; dyslexia (which is associated with eye movement problems) is linked to a specific visual perceptual deficit in the M pathway, a major recipient of which is the colliculus. Whether or not the SC is indeed hyper-responsive in ADHD as Hypothesis 1 suggests, the SC may well represent an important therapeutic target for drugs. In fact current psychostimulant therapies, which reduce distractibility, may already work at that level (Hypothesis 2), a contention which is supported by: 1. The

  2. Connections between intraparietal sulcus and a sensorimotor network underpin sustained tactile attention.

    Science.gov (United States)

    Goltz, Dominique; Gundlach, Christopher; Nierhaus, Till; Villringer, Arno; Müller, Matthias; Pleger, Burkhard

    2015-05-20

    Previous studies on sustained tactile attention draw conclusions about underlying cortical networks by averaging over experimental conditions without considering attentional variance in single trials. This may have formed an imprecise picture of brain processes underpinning sustained tactile attention. In the present study, we simultaneously recorded EEG-fMRI and used modulations of steady-state somatosensory evoked potentials (SSSEPs) as a measure of attentional trial-by-trial variability. Therefore, frequency-tagged streams of vibrotactile stimulations were simultaneously presented to both index fingers. Human participants were cued to sustain attention to either the left or right finger stimulation and to press a button whenever they perceived a target pulse embedded in the to-be-attended stream. In-line with previous studies, a classical general linear model (GLM) analysis based on cued attention conditions revealed increased activity mainly in somatosensory and cerebellar regions. Yet, parametric modeling of the BOLD response using simultaneously recorded SSSEPs as a marker of attentional trial-by-trial variability quarried the intraparietal sulcus (IPS). The IPS in turn showed enhanced functional connectivity to a modality-unspecific attention network. However, this was only revealed on the basis of cued attention conditions in the classical GLM. By considering attentional variability as captured by SSSEPs, the IPS showed increased connectivity to a sensorimotor network, underpinning attentional selection processes between competing tactile stimuli and action choices (press a button or not). Thus, the current findings highlight the potential value by considering attentional variations in single trials and extend previous knowledge on the role of the IPS in tactile attention.

  3. Distance learning for similarity estimation

    NARCIS (Netherlands)

    Yu, J.; Amores, J.; Sebe, N.; Radeva, P.; Tian, Q.

    2008-01-01

    In this paper, we present a general guideline to find a better distance measure for similarity estimation based on statistical analysis of distribution models and distance functions. A new set of distance measures are derived from the harmonic distance, the geometric distance, and their generalized

  4. Distance learning for similarity estimation.

    Science.gov (United States)

    Yu, Jie; Amores, Jaume; Sebe, Nicu; Radeva, Petia; Tian, Qi

    2008-03-01

    In this paper, we present a general guideline to find a better distance measure for similarity estimation based on statistical analysis of distribution models and distance functions. A new set of distance measures are derived from the harmonic distance, the geometric distance, and their generalized variants according to the Maximum Likelihood theory. These measures can provide a more accurate feature model than the classical Euclidean and Manhattan distances. We also find that the feature elements are often from heterogeneous sources that may have different influence on similarity estimation. Therefore, the assumption of single isotropic distribution model is often inappropriate. To alleviate this problem, we use a boosted distance measure framework that finds multiple distance measures which fit the distribution of selected feature elements best for accurate similarity estimation. The new distance measures for similarity estimation are tested on two applications: stereo matching and motion tracking in video sequences. The performance of boosted distance measure is further evaluated on several benchmark data sets from the UCI repository and two image retrieval applications. In all the experiments, robust results are obtained based on the proposed methods.

  5. Comparison of hydrological similarity measures

    Science.gov (United States)

    Rianna, Maura; Ridolfi, Elena; Manciola, Piergiorgio; Napolitano, Francesco; Russo, Fabio

    2016-04-01

    The use of a traditional at site approach for the statistical characterization and simulation of spatio-temporal precipitation fields has a major recognized drawback. Indeed, the weakness of the methodology is related to the estimation of rare events and it involves the uncertainty of the at-site sample statistical inference, because of the limited length of records. In order to overcome the lack of at-site observations, regional frequency approach uses the idea of substituting space for time to estimate design floods. The conventional regional frequency analysis estimates quantile values at a specific site from multi-site analysis. The main idea is that homogeneous sites, once pooled together, have similar probability distribution curves of extremes, except for a scaling factor. The method for pooling groups of sites can be based on geographical or climatological considerations. In this work the region of influence (ROI) pooling method is compared with an entropy-based one. The ROI is a flexible pooling group approach which defines for each site its own "region" formed by a unique set of similar stations. The similarity is found through the Euclidean distance metric in the attribute space. Here an alternative approach based on entropy is introduced to cluster homogeneous sites. The core idea is that homogeneous sites share a redundant (i.e. similar) amount of information. Homogeneous sites are pooled through a hierarchical selection based on the mutual information index (i.e. a measure of redundancy). The method is tested on precipitation data in Central Italy area.

  6. Pre-attentive information processing and impulsivity in bipolar disorder.

    Science.gov (United States)

    Swann, Alan C; Lijffijt, Marijn; Lane, Scott D; Steinberg, Joel L; Acas, Michelle D; Cox, Blake; Moeller, F Gerard

    2013-12-01

    Early responses to stimuli can be measured by sensory evoked potentials (EP) using repeated identical stimuli, S1 and S2. Response to S1 may represent efficient stimulus detection, while suppression of response to S2 may represent inhibition. Early responses to stimuli may be related to impulsivity. We compared EP reflecting stimulus detection and inhibition in bipolar disorder and healthy controls, and investigated relationships to impulsivity. Subjects were 48 healthy controls without family histories of mood disorder and 48 with bipolar disorder. EP were measured as latencies and amplitudes for auditory P50 (pre-attentional), N100 (initial direction of attention) and P200 (initial conscious awareness), using a paired-click paradigm, with identical stimuli 0.5 s apart. Impulsivity was measured by questionnaire and by laboratory tests for inability to suppress responses to stimuli or to delay response for a reward. Analyses used general linear models. S1 amplitudes for P50, N100, and P200, and gating of N100 and P200, were lower in bipolar disorder than in controls. P50 S1 amplitude correlated with accurate laboratory-task responding, and S2 amplitude correlated with impulsive task performance and fast reaction times, in bipolar disorder. N100 and P200 EP did not correlate with impulsivity. These findings were independent of symptoms, treatment, or substance-use history. EPs were not related to questionnaire-measured or reward-based impulsivity. Bipolar I disorder is characterized by reduced pre-attentional and early attentional stimulus registration relative to controls. Within bipolar disorder, rapid-response impulsivity correlates with impaired pre-attentional response suppression. These results imply specific relationships between ERP-measured response inhibition and rapid-response impulsivity.

  7. Influence of auditory spatial attention on cross-modal semantic priming effect: evidence from N400 effect.

    Science.gov (United States)

    Wang, Hongyan; Zhang, Gaoyan; Liu, Baolin

    2017-01-01

    Semantic priming is an important research topic in the field of cognitive neuroscience. Previous studies have shown that the uni-modal semantic priming effect can be modulated by attention. However, the influence of attention on cross-modal semantic priming is unclear. To investigate this issue, the present study combined a cross-modal semantic priming paradigm with an auditory spatial attention paradigm, presenting the visual pictures as the prime stimuli and the semantically related or unrelated sounds as the target stimuli. Event-related potentials results showed that when the target sound was attended to, the N400 effect was evoked. The N400 effect was also observed when the target sound was not attended to, demonstrating that the cross-modal semantic priming effect persists even though the target stimulus is not focused on. Further analyses revealed that the N400 effect evoked by the unattended sound was significantly lower than the effect evoked by the attended sound. This contrast provides new evidence that the cross-modal semantic priming effect can be modulated by attention.

  8. HOW DISSIMILARLY SIMILAR ARE BIOSIMILARS?

    Directory of Open Access Journals (Sweden)

    Ramshankar Vijayalakshmi

    2012-05-01

    Full Text Available Recently Biopharmaceuticals are the new chemotherapeutical agents that are called as “Biosimilars” or “follow on protein products” by the European Medicines Agency (EMA and the American regulatory agencies (Food and Drug Administration respectively. Biosimilars are extremely similar to the reference molecule but not identical, however close their similarities may be. A regulatory framework is therefore in place to assess the application for marketing authorisation of biosimilars. When a biosimilar is similar to the reference biopharmaceutical in terms of safety, quality, and efficacy, it can be registered. It is important to document data from clinical trials with a view of similar safety and efficacy. If the development time for a generic medicine is around 3 years, a biosimilar takes about 6-9 years. Generic medicines need to demonstrate bioequivalence only unlike biosimilars that need to conduct phase I and Phase III clinical trials. In this review, different biosimilars that are already being used successfully in the field on Oncology is discussed. Their similarity, differences and guidelines to be followed before a clinically informed decision to be taken, is discussed. More importantly the regulatory guidelines that are operational in India with a work flow of making a biosimilar with relevant dos and dont’s are discussed. For a large populous country like India, where with improved treatments in all sectors including oncology, our ageing population is increasing. For the health care of this sector, we need more newer, cheaper and effective biosimilars in the market. It becomes therefore important to understand the regulatory guidelines and steps to come up with more biosimilars for the existing population and also more information is mandatory for the practicing clinicians to translate these effectively into clinical practice.

  9. The Relationship between Attention Deficit Hyperactivity Disorder and Child Temperament

    Science.gov (United States)

    Foley, Marie; McClowry, Sandra Graham; Castellanos, Francisco X.

    2008-01-01

    This study examined empirical and theoretical differences and similarities between attention deficit hyperactivity disorder (ADHD) and child temperament in 32 ADHD children aged 6-11 years, and a comparison group of 23 children with similar sociodemographic characteristics. Children were assessed for ADHD symptoms (hyperactivity, impulsivity, and…

  10. Attentional processing of multiple targets and distractors.

    Science.gov (United States)

    Munneke, Jaap; Fait, Elisa; Mazza, Veronica

    2013-11-01

    We assessed the functioning of attention when multiple relevant objects are intermingled with multiple distractors, measuring two electrophysiological subcomponents of the N2pc that have been associated, respectively, with target selection and distractor suppression: the target negativity (Nt) and the distractor positivity (Pd). To this aim, we orthogonally manipulated the number of targets and distractors in an enumeration task. The Nt was modulated by target, but not distractor numerosity, suggesting that an increase in target numerosity leads to an increase in attentional resources needed to form individual representations of the targets. In contrast, the number of distractors did not differentially alter the Pd. We hypothesize that distractors sharing similar visual features can be processed (and possibly suppressed) as a set, without the need for individuation.

  11. BRAIN DYSFUNCTION OF PATIENTS WITH QIGONG INDUCED MENTAL DISORDER REVEALED BY EVOKED POTENTIALS RECORDING

    Institute of Scientific and Technical Information of China (English)

    LU Yingzhi; ZONG Wenbin; CHEN Xingshi

    2003-01-01

    Objective: In order to investigate the brain function of patients with Qigong induced mental disorder (QIMD), this study was carried out. Methods: Four kinds of evoked potentials, including contingent negative variation (CNV), auditory evoked potentials (AEP), visual evoked potentials (VEP), and somatosensory evoked potentials (SEP), were recorded from 12 patients with Qigong induced mental disorder.Comparison of their evoked potentials with the data from some normal controls was made. Results: The results revealed that there were 3 kinds of abnormal changes in evoked potentials of patients with QIMD that is latency prolongation, amplitude increase and amplitude decrease, as compared with normal controls. Conclusion: Brain dysfunction of patients with QIMD was confirmed. Its biological mechanism needs further studying.

  12. Comparison Acoustically Evoked Short Latency Negative Response with Vestibular Evoked Myogenic Potential in Adults with Profound Hearing Loss

    Directory of Open Access Journals (Sweden)

    Maryam Ramezani

    2012-03-01

    Full Text Available Background and Aim: A negative deflection with a 3-4 ms latency period has been reported to exist within the auditory brainstem response of some patients with profound hearing loss following a strong acoustic stimulus. This deflection, namingly the n3 or the acoustically evoked short latency negative response is assumed to be a vestibular-evoked potential, especially of saccular origin. Since the myogenic potential is also saccular in origin, the purpose of the present study was to investigate the relationship between these two tests in adults with profound hearing loss.Methods: The present cross sectional study was performed on 20 profoundly deaf volunteers(39 ears who aged between 18-40 years old, randomly selected from available deaf adults in Tehran. The auditory brainstem response of all subjects was recorded following a 1000 Hz tone burst in 70-100dB nHL. Subjects were also tested for vestibular evoked myogenic potential.Results: Only 34 of 39 ears recorded myogenic potential that negative response was recorded in 27 of 34 ears with normal p13 and n23. In seven ears with normal p13 and n23, the negative response was absent. In 3 ears with no p13 and n23, the negative response was observed, and two none.Conclusion: In view of the high prevalance of the negative response in profoundly deaf ears with normal p13 and n23, it could be concluded that the negative response can be used when for any reason, it is not possible to record myogenic potential and be considered as a new test in vestibular test battery.

  13. Local Community Detection Using Link Similarity

    Institute of Scientific and Technical Information of China (English)

    Ying-Jun Wu; Han Huang; Zhi-Feng Hao; Feng Chen

    2012-01-01

    Exploring local community structure is an appealing problem that has drawn much recent attention in the area of social network analysis.As the complete information of network is often difficult to obtain,such as networks of web pages,research papers and Facebook users,people can only detect community structure from a certain source vertex with limited knowledge of the entire graph.The existing approaches do well in measuring the community quality,but they are largely dependent on source vertex and putting too strict policy in agglomerating new vertices.Moreover,they have predefined parameters which are difficult to obtain.This paper proposes a method to find local community structure by analyzing link similarity between the community and the vertex.Inspired by the fact that elements in the same community are more likely to share common links,we explore community structure heuristically by giving priority to vertices which have a high link similarity with the community.A three-phase process is also used for the sake of improving quality of community structure.Experimental results prove that our method performs effectively not only in computer-generated graphs but also in real-world graphs.

  14. Rewards teach visual selective attention.

    Science.gov (United States)

    Chelazzi, Leonardo; Perlato, Andrea; Santandrea, Elisa; Della Libera, Chiara

    2013-06-07

    Visual selective attention is the brain function that modulates ongoing processing of retinal input in order for selected representations to gain privileged access to perceptual awareness and guide behavior. Enhanced analysis of currently relevant or otherwise salient information is often accompanied by suppressed processing of the less relevant or salient input. Recent findings indicate that rewards exert a powerful influence on the deployment of visual selective attention. Such influence takes different forms depending on the specific protocol adopted in the given study. In some cases, the prospect of earning a larger reward in relation to a specific stimulus or location biases attention accordingly in order to maximize overall gain. This is mediated by an effect of reward acting as a type of incentive motivation for the strategic control of attention. In contrast, reward delivery can directly alter the processing of specific stimuli by increasing their attentional priority, and this can be measured even when rewards are no longer involved, reflecting a form of reward-mediated attentional learning. As a further development, recent work demonstrates that rewards can affect attentional learning in dissociable ways depending on whether rewards are perceived as feedback on performance or instead are registered as random-like events occurring during task performance. Specifically, it appears that visual selective attention is shaped by two distinct reward-related learning mechanisms: one requiring active monitoring of performance and outcome, and a second one detecting the sheer association between objects in the environment (whether attended or ignored) and the more-or-less rewarding events that accompany them. Overall this emerging literature demonstrates unequivocally that rewards "teach" visual selective attention so that processing resources will be allocated to objects, features and locations which are likely to optimize the organism's interaction with the

  15. Contrast independence of dynamic random dot correlogram evoked VEP amplitude.

    Science.gov (United States)

    Markó, Katalin; Kiss, Huba J M; Mikó-Baráth, Eszter; Bártfai, Orsolya; Török, Béla; Kovács, Ilona; Jandó, Gábor

    2009-04-06

    Dynamic random dot correlograms (DRDCs) are binocular stimuli that evoke a percept and a visual evoked potential (VEP) only in case of a mature and functional binocular system. DRDC-VEP is a method extensively used to study cortical binocularity in human infants and nonverbal children. Although the DRDC-VEP was invented 3 decades ago, neither the fundamental parameters, including contrast, of the stimulation nor the cerebral processing mechanisms have been clarified. The objective of the present study was to investigate the variability and detectability of adults' VEPs to DRDC under different stimulus contrast conditions. DRDCs were presented on the red and green channels of a computer monitor and were viewed with red-green goggles. The steady state DRDC-VEPs were recorded in healthy adult volunteers, and response reliability was assessed by the T(circ)(2) statistic. DRDC-VEP amplitude was independent of contrast, while VEP phases showed a weak correlation with contrast. Contrast invariance of DRDC-VEP amplitude suggests a very high contrast gain and dominant magnocellular input to the binocular correlation processing system.

  16. NGF-evoked sensitization of muscle fascia nociceptors in humans.

    Science.gov (United States)

    Deising, Saskia; Weinkauf, Benjamin; Blunk, James; Obreja, Otilia; Schmelz, Martin; Rukwied, Roman

    2012-08-01

    Nerve growth factor (NGF) induces local hyperalgesia for a few days after intramuscular injection, but longer-lasting muscle pain upon systemic administration. As the muscle fascia is densely innervated by free nerve endings, we hypothesized a lasting sensitization of fascia nociceptors by NGF. We administered 1 μg NGF (dissolved in 100 μL saline) ultrasound-guided to the fascia of the Musculus erector spinae muscle at the lumbar level of 14 male volunteers and assessed hypersensitivity after 6 hours, and 1, 3, 7, 14, and 21 days. Pain upon mechanical stimuli (constant pressure and dynamic impact), upon exercise and electrically induced M. erector spinae contraction, and upon injection of 100 μL phosphate buffer pH4 (at day 7 and 14 only) to the fascia of both NGF- and saline-treated muscles, was investigated. Injections into the muscle fascia did not cause acute pain. Local heat pain thresholds were unchanged following NGF and saline (control) administration. NGF evoked a lasting (days 1-7) and significant reduction of pressure pain, pressure thresholds, exercise-evoked muscle pain, and hyperalgesia to impact stimuli (12 m/s). Pain upon injected protons was significantly elevated (Pfascia to mechanical and chemical stimuli lasting for up to 2 weeks. As nociceptors in the fascia appear to be particularly prone to sensitization, they may contribute to acute or chronic muscle pain.

  17. Evoked brain potentials and disability in brain-damaged patients.

    Science.gov (United States)

    Rappaport, M; Hall, K; Hopkins, K; Belleza, T; Berrol, S; Reynolds, G

    1977-08-01

    Various measures of evoked brain potential abnormality (EPA) were correlated with disability ratings (DR) for 35 brain-damaged patients. EPA data consisted of judgements of abnormality of ipsilateral, contralateral and bilateral responses to auditory and visual stimuli reflecting activity in the brain stem, subcortex and cortex. DR data were obtained from a scale developed for this study to quantize and categorize patients with a wide range of disabilities from coma to normal functioning. EPA scores based on visual and auditory cortical responses showed significantly positive correlations with degree of disability. Visual response correlation was .49, auditory .38 and combined visual and auditory .51. It was concluded that EPA measures can reflect disability independently of clinical information. They are useful in assessing brain function in general and, specifically, in assessing impairment of sensory function. The evoked potential technique was particularly useful in patients who were not able to participate fully in their own examination. There were indications that the technique may also be valuable in monitoring progress and in predicting clinical outcome in brain-damaged patients.

  18. Music-evoked emotions: principles, brain correlates, and implications for therapy.

    Science.gov (United States)

    Koelsch, Stefan

    2015-03-01

    This paper describes principles underlying the evocation of emotion with music: evaluation, resonance, memory, expectancy/tension, imagination, understanding, and social functions. Each of these principles includes several subprinciples, and the framework on music-evoked emotions emerging from these principles and subprinciples is supposed to provide a starting point for a systematic, coherent, and comprehensive theory on music-evoked emotions that considers both reception and production of music, as well as the relevance of emotion-evoking principles for music therapy.

  19. [Exploration of the optic and somatosensory pathways with cerebral evoked potentials].

    Science.gov (United States)

    Ghezzi, A; Zibetti, A

    1981-06-16

    Visual and somatosensorial evoked potentials are the electrical response, recorded on the scalp, that follows the presentation of visual and sensorial stimuli. After briefly mentioning the technical premises enabling evoked responses to be obtained from EEC activity, some cases are reported (demyelining, degenerative, compressive, ischaemic, anoxic pathology) where visual or sensory evoked potentials presented changes, proof of the usefulness of these techniques for the purposes of clinical documentation or for diagnosis in different fields of DNS pathology.

  20. Early vision and visual attention

    Directory of Open Access Journals (Sweden)

    Gvozdenović Vasilije P.

    2003-01-01

    Full Text Available The question whether visual perception is spontaneous, sudden or is running through several phases, mediated by higher cognitive processes, was raised ever since the early work of Gestalt psychologists. In the early 1980s, Treisman proposed the feature integration theory of attention (FIT, based on the findings of neuroscience. Soon after publishing her theory a new scientific approach appeared investigating several visual perception phenomena. The most widely researched were the key constructs of FIT, like types of visual search and the role of the attention. The following review describes the main studies of early vision and visual attention.

  1. The role of long-term familiarity and attentional maintenance in short-term memory for timbre.

    Science.gov (United States)

    Siedenburg, Kai; McAdams, Stephen

    2017-04-01

    We study short-term recognition of timbre using familiar recorded tones from acoustic instruments and unfamiliar transformed tones that do not readily evoke sound-source categories. Participants indicated whether the timbre of a probe sound matched with one of three previously presented sounds (item recognition). In Exp. 1, musicians better recognised familiar acoustic compared to unfamiliar synthetic sounds, and this advantage was particularly large in the medial serial position. There was a strong correlation between correct rejection rate and the mean perceptual dissimilarity of the probe to the tones from the sequence. Exp. 2 compared musicians' and non-musicians' performance with concurrent articulatory suppression, visual interference, and with a silent control condition. Both suppression tasks disrupted performance by a similar margin, regardless of musical training of participants or type of sounds. Our results suggest that familiarity with sound source categories and attention play important roles in short-term memory for timbre, which rules out accounts solely based on sensory persistence.

  2. A change in the parameters of P300 evoked potentials in relation to the degree of exacerbation of pain syndrome

    Directory of Open Access Journals (Sweden)

    A P Rachin

    2012-01-01

    Full Text Available In chronic pain, the state of suprasegmental brain structures (the cortex, limbic system, truncodiencephalic structures, which form the motivational-affective and cognitive components of pain behavior, actively affects pain afferentation as well. The purpose of the study was to comparatively analyze the parameters and topographic distribution of P300 cognitive evoked potential in patients with lower back pain. Sixty patients aged 22 to 60 years were examined. The authors made their clinical and neurological examinations, collected medical history data, and assessed back pain intensity by a visual analog scale. The findings were compared with the parameters of cognitive evoked potentials (the separating of P300 to count; keystroke in the recognition of significant stimuli; elaboration of a verbal and nonverbal visual stimulation protocol, by using emotionally significant stimuli. The processes of recognition and differentiation, those of directed attention, and the rate of information processing slowed down in patients with different stages of pain syndrome. The P300 separating procedure using the emotionally significant stimuli allows one to assess the specific features of chronization of pain syndromes and the presence of pain memory in the central nervous system of such patients. The estimation of P300 parameters over time or during treatment are of particular value for the optimization and evaluation of its efficiency.

  3. Long-range neural activity evoked by premotor cortex stimulation: a TMS/EEG co-registration study

    Directory of Open Access Journals (Sweden)

    Marco eZanon

    2013-11-01

    Full Text Available The premotor cortex is one of the fundamental structures composing the neural networks of the human brain. It is implicated in many behaviors and cognitive tasks, ranging from movement to attention and eye-related activity. Therefore, neural circuits that are related to premotor cortex have been studied to clarify their connectivity and/or role in different tasks. In the present work, we aimed to investigate the propagation of the neural activity evoked in the dorsal premotor cortex using transcranial magnetic stimulation/electroencephalography (TMS/EEG. Towards this end, interest was focused on the neural dynamics elicited in long-ranging temporal and spatial networks. Twelve healthy volunteers underwent a single-pulse TMS protocol in a resting condition with eyes closed, and the evoked activity, measured by EEG, was compared to a sham condition in a time window ranging from 45 msec to about 200 msec after TMS. Spatial and temporal investigations were carried out with sLORETA. TMS was found to induce propagation of neural activity mainly in the contralateral sensorimotor and frontal cortices, at about 130 msec after delivery of the stimulus. Different types of analyses showed propagated activity also in posterior, mainly visual, regions, in a time window between 70 and 130 msec. Finally, a likely rebounding activation of the sensorimotor and frontal regions, was observed in various time ranges. Taken together, the present findings further characterize the neural circuits that are driven by dorsal premotor cortex activation in healthy humans.

  4. Sparse Similarity-Based Fisherfaces

    DEFF Research Database (Denmark)

    Fagertun, Jens; Gomez, David Delgado; Hansen, Mads Fogtmann;

    2011-01-01

    In this work, the effect of introducing Sparse Principal Component Analysis within the Similarity-based Fisherfaces algorithm is examined. The technique aims at mimicking the human ability to discriminate faces by projecting the faces in a highly discriminative and easy interpretative way. Pixel...... obtain the same recognition results as the technique in a dense version using only a fraction of the input data. Furthermore, the presented results suggest that using SPCA in the technique offers robustness to occlusions....

  5. Self-similarity Driven Demosaicking

    Directory of Open Access Journals (Sweden)

    Antoni Buades

    2011-06-01

    Full Text Available Digital cameras record only one color component per pixel, red, green or blue. Demosaicking is the process by which one can infer a whole color matrix from such a matrix of values, thus interpolating the two missing color values per pixel. In this article we propose a demosaicking method based on the property of non-local self-similarity of images.

  6. Active browsing using similarity pyramids

    Science.gov (United States)

    Chen, Jau-Yuen; Bouman, Charles A.; Dalton, John C.

    1998-12-01

    In this paper, we describe a new approach to managing large image databases, which we call active browsing. Active browsing integrates relevance feedback into the browsing environment, so that users can modify the database's organization to suit the desired task. Our method is based on a similarity pyramid data structure, which hierarchically organizes the database, so that it can be efficiently browsed. At coarse levels, the similarity pyramid allows users to view the database as large clusters of similar images. Alternatively, users can 'zoom into' finer levels to view individual images. We discuss relevance feedback for the browsing process, and argue that it is fundamentally different from relevance feedback for more traditional search-by-query tasks. We propose two fundamental operations for active browsing: pruning and reorganization. Both of these operations depend on a user-defined relevance set, which represents the image or set of images desired by the user. We present statistical methods for accurately pruning the database, and we propose a new 'worm hole' distance metric for reorganizing the database, so that members of the relevance set are grouped together.

  7. Self-Similar Collisionless Shocks

    CERN Document Server

    Katz, B; Waxman, E; Katz, Boaz; Keshet, Uri; Waxman, Eli

    2006-01-01

    Observations of gamma-ray burst afterglows suggest that the correlation length of magnetic field fluctuations downstream of relativistic non-magnetized collisionless shocks grows with distance from the shock to scales much larger than the plasma skin depth. We argue that this indicates that the plasma properties are described by a self-similar solution, and derive constraints on the scaling properties of the solution. For example, we find that the scaling of the characteristic magnetic field amplitude with distance from the shock is B \\propto D^{s_B} with -1 \\propto x^{2s_B} (for x>>D). We show that the plasma may be approximated as a combination of two self-similar components: a kinetic component of energetic particles and an MHD-like component representing "thermal" particles. We argue that the latter may be considered as infinitely conducting, in which case s_B=0 and the scalings are completely determined (e.g. dn/dE \\propto E^{-2} and B \\propto D^0). Similar claims apply to non- relativistic shocks such a...

  8. Roget's Thesaurus and Semantic Similarity

    CERN Document Server

    Jarmasz, Mario

    2012-01-01

    We have implemented a system that measures semantic similarity using a computerized 1987 Roget's Thesaurus, and evaluated it by performing a few typical tests. We compare the results of these tests with those produced by WordNet-based similarity measures. One of the benchmarks is Miller and Charles' list of 30 noun pairs to which human judges had assigned similarity measures. We correlate these measures with those computed by several NLP systems. The 30 pairs can be traced back to Rubenstein and Goodenough's 65 pairs, which we have also studied. Our Roget's-based system gets correlations of .878 for the smaller and .818 for the larger list of noun pairs; this is quite close to the .885 that Resnik obtained when he employed humans to replicate the Miller and Charles experiment. We further evaluate our measure by using Roget's and WordNet to answer 80 TOEFL, 50 ESL and 300 Reader's Digest questions: the correct synonym must be selected amongst a group of four words. Our system gets 78.75%, 82.00% and 74.33% of ...

  9. Cell-attached recordings of responses evoked by photorelease of GABA in the immature cortical neurons

    Directory of Open Access Journals (Sweden)

    Marat eMinlebaev

    2013-05-01

    Full Text Available We present a novel non-invasive technique to measure the polarity of GABAergic responses based on cell-attached recordings of currents activated by laser-uncaging of GABA. For these recordings, a patch pipette was filled with a solution containing RuBi-GABA, and GABA was released from this complex by a laser beam conducted to the tip of the patch pipette via an optic fiber. In cell-attached recordings from neocortical and hippocampal neurons in postnatal days P2-5 rat brain slices in vitro, we found that laser-uncaging of GABA activates integral cell-attached currents mediated by tens of GABA(A channels. The initial response was inwardly directed, indicating a depolarizing response to GABA. The direction of the initial response was dependent on the pipette potential and analysis of its slope-voltage relationships revealed a depolarizing driving force of +11 mV for the currents through GABA channels. Initial depolarizing responses to GABA uncaging were inverted to hyperpolarizing in the presence of the NKCC1 blocker bumetanide. Current-voltage relationships of the currents evoked by Rubi-GABA uncaging using voltage-ramps at the peak of responses not only revealed a bumetanide-sensitive depolarizing reversal potential of the GABA(A receptor mediated responses, but also showed a strong voltage-dependent hysteresis. Upon desensitization of the uncaged-GABA response, current-voltage relationships of the currents through single GABA(A channels revealed depolarizing responses with the driving force values similar to those obtained for the initial response. Thus, cell-attached recordings of the responses evoked by local intrapipette GABA uncaging are suitable to assess the polarity of the GABA(A-Rs mediated signals in small cell compartments.

  10. Usage of Multimodal Evoked Potentials in Diagnosis of Changes in Central Nervous System in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Bahar Özbek

    2011-03-01

    Full Text Available OBJECTIVE: Evoked potentials are used in the functional assessment of sensory and motor pathways. Conflicting results have been reported in different studies about the value of evoked potentials in demyelinating diseases. Over 80% of patients with multiple sclerosis present with a relapsing–remitting form of the disease. In this study we aimed to examine the value of each evoked potential to demonstrate the demyelinating lesions in a homogenous group of patients with relapsing remitting multiple sclerosis. We also aimed to examine the correlation between clinical status and evoked potential abnormalities. METHODS: Twenty patients with relapsing remitting multiple sclerosis and ten healthy volunteers were included in the study to evaluate the value of evoked potentials in a homogenous group. Visual, somatosensory and motor evoked potentials were measured and EDSS scores of the patients were calculated. RESULTS: Of 20 patients, 15 patients(75% had VEP abnormality, 14 patients (70% had MEP abnormality and 12 patients (60% had tibial SEP abnormality. All patients had at least one abnormal evoked potential measurement. The abnormality of evoked potentials also had a correlation with high EDSS scores. CONCLUSION: We concluded that evoked potentials, especially used in combination, are good markers to show the nervous damage in patients with multiple sclerosis.

  11. Common cortical responses evoked by appearance, disappearance and change of the human face

    Directory of Open Access Journals (Sweden)

    Kida Tetsuo

    2009-04-01

    Full Text Available Abstract Background To segregate luminance-related, face-related and non-specific components involved in spatio-temporal dynamics of cortical activations to a face stimulus, we recorded cortical responses to face appearance (Onset, disappearance (Offset, and change (Change using magnetoencephalography. Results Activity in and around the primary visual cortex (V1/V2 showed luminance-dependent behavior. Any of the three events evoked activity in the middle occipital gyrus (MOG at 150 ms and temporo-parietal junction (TPJ at 250 ms after the onset of each event. Onset and Change activated the fusiform gyrus (FG, while Offset did not. This FG activation showed a triphasic waveform, consistent with results of intracranial recordings in humans. Conclusion Analysis employed in this study successfully segregated four different elements involved in the spatio-temporal dynamics of cortical activations in response to a face stimulus. The results show the responses of MOG and TPJ to be associated with non-specific processes, such as the detection of abrupt changes or exogenous attention. Activity in FG corresponds to a face-specific response recorded by intracranial studies, and that in V1/V2 is related to a change in luminance.

  12. Long-latency auditory evoked potentials with verbal and nonverbal stimuli,

    Directory of Open Access Journals (Sweden)

    Sheila Jacques Oppitz

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. OBJECTIVE: To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. METHODS: A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000 Hz - frequent and 4000 Hz - rare; and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare. RESULTS: Considering the component N2 for tone burst, the lowest latency found was 217.45 ms for the BA/DI stimulus; the highest latency found was 256.5 ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340 ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. CONCLUSION: There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude.

  13. [Contribution of cognitive evoked potentials for detecting early cognitive disorders in multiple sclerosis].

    Science.gov (United States)

    Magnié, M N; Bensa, C; Laloux, L; Bertogliati, C; Faure, S; Lebrun, C

    2007-11-01

    In Multiple Sclerosis (MS), one of the most frequent neurological diseases in young adults, cognitive dysfunctions have been under considered whereas their evolution may produce a fronto-sous-cortical deterioration and more than half of the MS patients present such dysfunctions. Nevertheless sensory evoked-potentials are classically used in this disease, event-related potentials (ERP) are not included in the clinical exploration of MS. Two studies are presented aimed at further tracking the usefulness of ERP for detecting early cognitive dysfunctions in MS. All of the patients presented a relapsing remitting MS for less than 5 years with a moderate physical handicap and complained from their memory. They performed a neuropsychological set and ERP were elicited using the oddball paradigm in both modalities, visual and auditory. In the first study, 10 patients without cognitive dysfunction at the neuropsychological evaluation and 10 patients with an attention deficit participated with 10 age-matched controls. In the second study, 10 patients with memory impairment at the neuropsychological evaluation and 10 age-matched controls were included. Our data argue for an earlier modification of ERP parameters in the visual modality than in the auditory one, even before the modification of cognitive scores. In both studies, P300 parameters were correlated to neuropsychological performances (and especially to the attention examination in the first study and to memory tests in the second study) in both modalities. Taking into account the clinical usefulness of ERPs, it is nowadays important to include this electrophysiological method in evaluation and follow-up of MS, and not only using the auditory modality but also the visual presentation in order to detect earlier cognitive dysfunctions even before modification of neuropsychological performances.

  14. Usability of a theory of visual attention (TVA) for parameter-based measurement of attention I

    DEFF Research Database (Denmark)

    Finke, Kathrin; Bublak, Peter; Krummenacher, Joseph

    2005-01-01

    The present study investigated the usability of whole and partial report of briefly displayed letter arrays as a diagnostic tool for the assessment of attentional functions. The tool is based on Bundesen’s (1990, 1998, 2002; Bundesen et al., 2005) theory of visual attention (TVA), which assumes f...... clinical tests measuring similar constructs. The empirical independence of the four TVA parameters is suggested by nonsignificant or, in the case of processing speed and working memory storage capacity, only modest correlations between the parameter values.......The present study investigated the usability of whole and partial report of briefly displayed letter arrays as a diagnostic tool for the assessment of attentional functions. The tool is based on Bundesen’s (1990, 1998, 2002; Bundesen et al., 2005) theory of visual attention (TVA), which assumes...... of these parameters. The present study was designed to examine whether (a) a shortened procedure bears sufficient accuracy and reliability, (b) whether the procedures reveal attentional constructs with clinical relevance, and (c) whether the mathematically independent parameters are also empirically independent...

  15. Targeted Communication and Investor Attention

    OpenAIRE

    Boulland, Romain; Degeorge, François; Ginglinger, Edith

    2012-01-01

    In the spirit of Merton (1987) we find that targeted communication by firms raises investor attention. Continental European firms using English-language commercial press wires to disseminate corporate press releases exhibit less drift and more trading volume after their earnings announcements than firms that do not, consistent with communication on English speaking wires raising investor attention. Continental European firms using English-language commercial press wires also receive more pres...

  16. Faking Attention Deficit Hyperactivity Disorder

    OpenAIRE

    2011-01-01

    Attention-deficit hyperactivity disorder is a common malady in the general population, with up to 8.1 percent of adults meeting criteria for this syndrome. In the college setting, the diagnosis of attention deficit hyperactivity disorder may offer specific academic advantages. Once the diagnosis is assigned, the prescription of stimulant medication may provide additional secondary gains through misuse and/or diversion. For example, these drugs may be used by college consumers to increase aler...

  17. Adaptive Fourier series modeling of time-varying evoked potentials: study of human somatosensory evoked response to etomidate anesthetic.

    Science.gov (United States)

    Thakor, N V; Vaz, C A; McPherson, R W; Hanley, D F

    1991-01-01

    Evoked potentials (EPs) have traditionally been analyzed in time domain, with amplitude and latency of various signal components used in clinical interpretation. A new approach, called adaptive Fourier series modeling (FSM), is presented here. Dynamic changes in magnitudes of Fourier coefficients are analyzed for diagnostic purposes. In order to estimate the time-varying changes in the Fourier coefficients of noisy signals, a least mean-square filtering algorithm is applied. Results of computer simulations as well as experimental data are presented. Time-varying trends are presented in a new compressed evoked spectrum format. These techniques are applied to the study of alterations in human somatosensory EPs caused by the intravenous administration of etomidate during neurosurgical procedures. Amplitude increases of the order of 200-500% occurring within a time span of about 100 sec were captured. Due to its superior convergence properties, the adaptive FSM technique estimates more rapid changes in amplitude and latency than exponentially weighted averaging or moving window averaging schemes.

  18. Attentional Networks and Biological Motion

    Directory of Open Access Journals (Sweden)

    Chandramouli Chandrasekaran

    2010-03-01

    Full Text Available Our ability to see meaningful actions when presented with pointlight traces of human movement is commonly referred to as the perception of biological motion. While traditionalexplanations have emphasized the spontaneous and automatic nature of this ability, morerecent findings suggest that attention may play a larger role than is typically assumed. Intwo studies we show that the speed and accuracy of responding to point-light stimuli is highly correlated with the ability to control selective attention. In our first experiment we measured thresholds for determining the walking direction of a masked point-light figure, and performance on a range of attention-related tasks in the same set of observers. Mask-density thresholds for the direction discrimination task varied quite considerably from observer to observer and this variation was highly correlated with performance on both Stroop and flanker interference tasks. Other components of attention, such as orienting, alerting and visual search efficiency, showed no such relationship. In a second experiment, we examined the relationship between the ability to determine the orientation of unmasked point-light actions and Stroop interference, again finding a strong correlation. Our results are consistent with previous research suggesting that biological motion processing may requite attention, and specifically implicate networks of attention related to executive control and selection.

  19. Visual attention in posterior stroke

    DEFF Research Database (Denmark)

    Fabricius, Charlotte; Petersen, Anders; Iversen, Helle K

    Objective: Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere. However, attentional effects of more posterior lesions are less clear. The aim of this study was to characterize visual processing speed and appre......Objective: Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere. However, attentional effects of more posterior lesions are less clear. The aim of this study was to characterize visual processing speed...... and apprehension span following posterior cerebral artery (PCA) stroke. We also relate these attentional parameters to visual word recognition, as previous studies have suggested that reduced visual speed and span may explain pure alexia. Methods: Nine patients with MR-verified focal lesions in the PCA......-territory (four left PCA; four right PCA; one bilateral, all >1 year post stroke) were compared to 25 controls using single case statistics. Visual attention was characterized by a whole report paradigm allowing for hemifield-specific speed and span measurements. We also characterized visual field defects...

  20. Assessing protein kinase target similarity

    DEFF Research Database (Denmark)

    Gani, Osman A; Thakkar, Balmukund; Narayanan, Dilip

    2015-01-01

    : focussed chemical libraries, drug repurposing, polypharmacological design, to name a few. Protein kinase target similarity is easily quantified by sequence, and its relevance to ligand design includes broad classification by key binding sites, evaluation of resistance mutations, and the use of surrogate......" of sequence and crystal structure information, with statistical methods able to identify key correlates to activity but also here, "the devil is in the details." Examples from specific repurposing and polypharmacology applications illustrate these points. This article is part of a Special Issue entitled...

  1. Sustained attention in context conditioning: Evidence from steady-state VEPs.

    Science.gov (United States)

    Kastner, Anna K; Pauli, Paul; Wieser, Matthias J

    2015-12-01

    In classical fear conditioning an aversive event is paired repeatedly with a predictive stimulus, which later elicits fear. Repeated presentation of an aversive event in the absence of a predictive cue however may induce anxiety, and the context may gain a threatening value. As such conditioned anxiety can be considered a sustained reaction compared to phasic fear, it would be interesting to track continuous cortical responses during context conditioning. The present study realized a differential context conditioning paradigm and assessed sustained cortical activations to the threatening and the safe context and how neutral cues are processed within both contexts. Two pictures of different office rooms presented for 20s served as contexts. One room became associated with an unpleasant noise that was presented unpredictably (CTX+) while the other office (CTX-) was never associated with this unpleasant noise. After acquisition, a social agent or an object was presented as a distractor in both contexts. Cortical activations in response to contexts and distractors were assessed separately by steady-state visually evoked potentials (ssVEPs) using frequency tagging. Results revealed enhanced ssVEP-amplitudes for CTX+ compared to CTX- in a lateral occipital cluster during acquisition. Similarly, CTX+ elicited higher ssVEP-amplitudes during the test phase, and these context conditioning effects were not reduced by the simultaneous presentation of novel distractors. These results indicate that context conditioning was successfully implemented and that the anxiety context received facilitated cortical processing across the whole viewing time. We conclude that threatening contexts capture attention over a longer period of time, and are immune to distraction by new objects.

  2. Effect of attention control on sustained attention during induced anxiety.

    Science.gov (United States)

    Grillon, Christian; Robinson, Oliver J; Mathur, Ambika; Ernst, Monique

    2016-01-01

    Anxiety has wide-reaching and complex effects on cognitive performance. Although it can intrude on cognition and interfere with performance, it can also facilitate information processing and behavioural responses. In a previous study, we showed that anxiety induced by threat of shock facilitates performance on the Sustained Attention to Response Task, a vigilance test, which probes response inhibition to infrequent nogo stimuli. The present study sought to identify factors that may have contributed to such improved performance, including on- and off-task thinking (assessed with thought probes) and individual differences in attention control, as measured with the Attention Control Scale. Replicating our prior finding, we showed that shock threat significantly reduced errors of commission on the nogo trials. However, we extended this finding in demonstrating that this effect was driven by subjects with low attention control. We therefore confirm that anxiety increases inhibitory control of prepotent responses--a mechanism which is adaptive under threat--and show that this effect is greater in those who rely more upon such prepotent responding, i.e., those with low attentional control.

  3. Assessment of visual disability using visual evoked potentials

    Directory of Open Access Journals (Sweden)

    Jeon Jihoon

    2012-08-01

    Full Text Available Abstract Background The purpose of this study is to validate the use of visual evoked potential (VEP to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions. Methods A retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9–42 years, 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19–36 years, 19 optic neuritis patients (19 eyes: ages 9–71 years, and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes. Results Linear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR of 38 eyes from normal (right eyes and amblyopic (amblyopic eyes subjects were significant [y = −0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = −0.072x + 1.22 (−0.072. This resulted in a prediction

  4. Spatial Tuning Studies of the Pattern Evoked Electroretinogram.

    Science.gov (United States)

    Thompson, Dorothy Ann

    1987-09-01

    Available from UMI in association with The British Library. The locus of origin of the pattern evoked electroretinogram, (PERG), has been the subject of considerable discussion. A novel approach was adopted in this study to further elaborate the nature of the PERG evoked by pattern onset/offset presentation. The PERG was found to be linearly related to stimulus contrast and in particular was linearly related to the temporal contrast of the retinal image, when elicited by patterns of low spatial frequency. At high spatial frequencies the retinal image contrast is significantly reduced because of optical degradation. This is described by the eye's modulation transfer function (MTF). The retinal contrasts of square wave grating and chequerboard patterns of increasing spatial frequency were found by filtering their Fourier transforms by the MTF. The filtered pattern harmonics were then resynthesised to constitute a profile of retinal image illuminance from which the temporal and spatial contrast of the image could be calculated. A space-averaged temporal contrast attenuation factor was applied to PERGs evoked by low spatial frequency patterns to predict the retinal illuminance response elicited by a finer pattern. The predicted response was subtracted from the recorded signal and the residual waveform was proposed to represent pattern specific activity. An additional correction for the attenuation of spatial contrast was applied to the extracted pattern specific response. Pattern specific responses are the predicted result of iso-contrast retinal pattern stimulation. The pattern specific responses demonstrate a striking bandpass spatial selectivity which peaks at higher spatial frequencies in the more central retina. The variation of spatial sensitivity with eccentricity corresponds closely with estimated ganglion receptive field centre separation and psychophysical data. The variation of retinal structure with eccentricity in the form of the volumes of the nuclear

  5. Attention and Visuospatial Working Memory Share the Same Processing Resources

    Directory of Open Access Journals (Sweden)

    Jing eFeng

    2012-04-01

    Full Text Available Attention and visuospatial working memory (VWM share very similar characteristics; both have the same upper bound of about four items in capacity and they recruit overlapping brain regions. We examined whether both attention and visuospatial working memory share the same processing resources using a novel dual-task-costs approach based on a load-varying dual-task technique. With sufficiently large loads on attention and VWM, considerable interference between the two processes was observed. A further load increase on either process produced reciprocal increases in interference on both processes, indicating that attention and VWM share common resources. More critically, comparison among four experiments on the reciprocal interference effects, as measured by the dual-task costs, demonstrates no significant contribution from additional processing other than the shared processes. These results support the notion that attention and VWM share the same processing resources.

  6. Mechanisms for similarity based cooperation

    Science.gov (United States)

    Traulsen, A.

    2008-06-01

    Cooperation based on similarity has been discussed since Richard Dawkins introduced the term “green beard” effect. In these models, individuals cooperate based on an aribtrary signal (or tag) such as the famous green beard. Here, two different models for such tag based cooperation are analysed. As neutral drift is important in both models, a finite population framework is applied. The first model, which we term “cooperative tags” considers a situation in which groups of cooperators are formed by some joint signal. Defectors adopting the signal and exploiting the group can lead to a breakdown of cooperation. In this case, conditions are derived under which the average abundance of the more cooperative strategy exceeds 50%. The second model considers a situation in which individuals start defecting towards others that are not similar to them. This situation is termed “defective tags”. It is shown that in this case, individuals using tags to cooperate exclusively with their own kind dominate over unconditional cooperators.

  7. Attention

    Science.gov (United States)

    Montessori, Maria

    2016-01-01

    "The Advanced Montessori Method, Volume 1" was published in 1918 in English and is considered a seminal work along with "The Montessori Method." In the foreword to this book, Mario Montessori writes: "...the refulgent figure of the child, Dr. Montessori pointed out, who had found his own path to mental health, who…

  8. Attention trees and semantic paths

    Science.gov (United States)

    Giusti, Christian; Pieroni, Goffredo G.; Pieroni, Laura

    2007-02-01

    In the last few decades several techniques for image content extraction, often based on segmentation, have been proposed. It has been suggested that under the assumption of very general image content, segmentation becomes unstable and classification becomes unreliable. According to recent psychological theories, certain image regions attract the attention of human observers more than others and, generally, the image main meaning appears concentrated in those regions. Initially, regions attracting our attention are perceived as a whole and hypotheses on their content are formulated; successively the components of those regions are carefully analyzed and a more precise interpretation is reached. It is interesting to observe that an image decomposition process performed according to these psychological visual attention theories might present advantages with respect to a traditional segmentation approach. In this paper we propose an automatic procedure generating image decomposition based on the detection of visual attention regions. A new clustering algorithm taking advantage of the Delaunay- Voronoi diagrams for achieving the decomposition target is proposed. By applying that algorithm recursively, starting from the whole image, a transformation of the image into a tree of related meaningful regions is obtained (Attention Tree). Successively, a semantic interpretation of the leaf nodes is carried out by using a structure of Neural Networks (Neural Tree) assisted by a knowledge base (Ontology Net). Starting from leaf nodes, paths toward the root node across the Attention Tree are attempted. The task of the path consists in relating the semantics of each child-parent node pair and, consequently, in merging the corresponding image regions. The relationship detected in this way between two tree nodes generates, as a result, the extension of the interpreted image area through each step of the path. The construction of several Attention Trees has been performed and partial

  9. Tracing the Attention of Moving Citizens

    CERN Document Server

    Wang, Cheng-Jun

    2016-01-01

    With the widespread use of mobile computing devices in contemporary society, our trajectories in the physical space and virtual world are increasingly closely connected. Using the anonymous smartphone data of $1 \\times 10^5$ users in 30 days, we constructed the mobility network and the attention network to study the correlations between online and offline human behaviours. In the mobility network, nodes are physical locations and edges represent the movements between locations, and in the attention network, nodes are websites and edges represent the switch of users between websites. We apply the box-covering method to renormalise the networks. The investigated network properties include the size of box $l_B$ and the number of boxes $N(l_B)$. We find two universal classes of behaviours: the mobility network is featured by a small-world property, $N(l_B) \\simeq e^{-l_B}$, whereas the attention network is characterised by a self-similar property $N(l_B) \\simeq l_B^{-\\gamma}$. In particular, with the increasing o...

  10. Interneurons targeting similar layers receive synaptic inputs with similar kinetics.

    Science.gov (United States)

    Cossart, Rosa; Petanjek, Zdravko; Dumitriu, Dani; Hirsch, June C; Ben-Ari, Yehezkel; Esclapez, Monique; Bernard, Christophe

    2006-01-01

    GABAergic interneurons play diverse and important roles in controlling neuronal network dynamics. They are characterized by an extreme heterogeneity morphologically, neurochemically, and physiologically, but a functionally relevant classification is still lacking. Present taxonomy is essentially based on their postsynaptic targets, but a physiological counterpart to this classification has not yet been determined. Using a quantitative analysis based on multidimensional clustering of morphological and physiological variables, we now demonstrate a strong correlation between the kinetics of glutamate and GABA miniature synaptic currents received by CA1 hippocampal interneurons and the laminar distribution of their axons: neurons that project to the same layer(s) receive synaptic inputs with similar kinetics distributions. In contrast, the kinetics distributions of GABAergic and glutamatergic synaptic events received by a given interneuron do not depend upon its somatic location or dendritic arborization. Although the mechanisms responsible for this unexpected observation are still unclear, our results suggest that interneurons may be programmed to receive synaptic currents with specific temporal dynamics depending on their targets and the local networks in which they operate.

  11. An electrophysiological insight into visual attention mechanisms underlying schizotypy.

    Science.gov (United States)

    Fuggetta, Giorgio; Bennett, Matthew A; Duke, Philip A

    2015-07-01

    A theoretical framework has been put forward to understand attention deficits in schizophrenia (Luck SJ & Gold JM. Biological Psychiatry. 2008; 64:34-39). We adopted this framework to evaluate any deficits in attentional processes in schizotypy. Sixteen low schizotypal (LoS) and 16 high schizotypal (HiS) individuals performed a novel paradigm combining a match-to-sample task, with inhibition of return (using spatially uninformative cues) and memory-guided efficient visual-search within one trial sequence. Behavioural measures and event-related potentials (ERPs) were recorded. Behaviourally, HiS individuals exhibited a spatial cueing effect while LoS individuals showed the more typical inhibition of return effect. These results suggest HiS individuals have a relative deficit in rule selection - the endogenous control process involved in disengaging attention from the uninformative location cue. ERP results showed that the late-phase of N2pc evoked by the target stimulus had greater peak latency and amplitude in HiS individuals. This suggests a relative deficit in the implementation of selection - the process of focusing attention onto target features that enhances relevant/suppresses irrelevant inputs. This is a different conclusion than when the same theoretical framework has been applied to schizophrenia, which argues little or no deficit in implementation of selection amongst patients. Also, HiS individuals exhibited earlier onset and greater amplitude of the mismatch-triggered negativity component. In summary, our results indicate deficits of both control and implementation of selection in HiS individuals.

  12. Multi-Channel Noise Reduced Visual Evoked Potential Analysis

    Science.gov (United States)

    Palaniappan, Ramaswamy; Raveendran, Paramesran; Nishida, Shogo

    In this paper, Principal Component Analysis (PCA) is used to reduce noise from multi-channel Visual Evoked Potential (VEP) signals. PCA is applied to reduce noise from multi-channel VEP signals because VEP signals are more correlated from one channel to another as compared to noise during visual perception. Emulated VEP signals contaminated with noise are used to show the noise reduction ability of PCA. These noise reduced VEP signals are analysed in the gamma spectral band to classify alcoholics and non-alcoholics with a Fuzzy ARTMAP (FA) neural network. A zero phase Butterworth digital filter is used to extract gamma band power in spectral range of 30 to 50 Hz from these noise reduced VEP signals. The results using 800 VEP signals give an average FA classification of 92.50 % with the application of PCA and 83.33 % without the application of PCA.

  13. Evoked potentials in Guillain-Barré syndrome.

    Science.gov (United States)

    Ropper, A H; Chiappa, K H

    1986-04-01

    We studied evoked potentials (EPs) in 27 patients with typical acute Guillain-Barré syndrome and 3 with Fisher's syndrome. Three of 21 had BAEP abnormalities: 1 with bilateral I-III, 1 with unilateral I-III, and another with unilateral III-V interwave latency prolongations. Three with Fisher's syndrome had normal BAEPs (one had a poorly formed wave V unilaterally with one click polarity only). Ten of 21 median nerve EPs and 9 of 12 peroneal or tibial nerve somatosensory EPs were abnormal. Seven patients with normal somatosensory EPs had abnormal F waves from the same nerve; none had normal late responses and abnormal somatosensory EPs. These observations differ from previous reports on the frequency and interpretation of EP abnormalities in Guillain-Barré syndrome.

  14. Stimulus-evoked outer segment changes in rod photoreceptors

    Science.gov (United States)

    Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Lu, Yiming; Gai, Shaoyan; Yao, Xincheng

    2016-06-01

    Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.

  15. Spatial coincidence modulates interaction between visual and somatosensory evoked potentials.

    Science.gov (United States)

    Schürmann, Martin; Kolev, Vasil; Menzel, Kristina; Yordanova, Juliana

    2002-05-07

    The time course of interaction between concurrently applied visual and somatosensory stimulation with respect to evoked potentials (EPs) was studied. Visual stimuli, either in the left or right hemifield, and electric stimuli to the left wrist were delivered either alone or simultaneously. Visual and somatosensory EPs were summed and compared to bimodal EPs (BiEP, response to actual combination of both modalities). Temporal coincidence of stimuli lead to sub-additive or over-additive amplitudes in BiEPs in several time windows between 75 and 275 ms. Additional effects of spatial coincidence (left wrist with left hemifield) were found between 75 and 300 ms and beyond 450 ms. These interaction effects hint at a temporo-spatial pattern of multiple brain areas participating in the process of multimodal integration.

  16. Auditory evoked field measurement using magneto-impedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K., E-mail: o-kabou@echo.nuee.nagoya-u.ac.jp; Tajima, S.; Song, D.; Uchiyama, T. [Graduate School of Engineering, Nagoya University, Nagoya (Japan); Hamada, N.; Cai, C. [Aichi Steel Corporation, Tokai (Japan)

    2015-05-07

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  17. Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior

    Science.gov (United States)

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2013-03-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its simple nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair was sufficient to force the animal to locate, turn towards and track virtual light gradients.

  18. Visual evoked potentials in neuromyelitis optica and its spectrum disorders.

    Science.gov (United States)

    Ringelstein, Marius; Kleiter, Ingo; Ayzenberg, Ilya; Borisow, Nadja; Paul, Friedemann; Ruprecht, Klemens; Kraemer, Markus; Cohn, Eva; Wildemann, Brigitte; Jarius, Sven; Hartung, Hans-Peter; Aktas, Orhan; Albrecht, Philipp

    2014-04-01

    Optic neuritis (ON) is a key feature of neuromyelitis optica (NMO). Recently, NMO patients of predominantly Afro-Brazilian origin were evaluated by visual evoked potentials (VEPs) and showed marked amplitude reductions. Here, we analyzed VEPs in a predominantly Caucasian cohort, consisting of 43 patients with definite NMO, 18 with anti-aquaporin (AQP) 4 antibody-seropositive NMO spectrum disorders and 61 matched healthy controls. We found reduced amplitudes in only 12.3%, prolonged latencies in 41.9% and a lack of response in 14.0% of NMO eyes. Delayed P100 latencies in eyes without prior ON suggested this was a subclinical affection. The data indicate heterogenous patterns in NMO, warranting further investigation.

  19. Automatic denoising of single-trial evoked potentials.

    Science.gov (United States)

    Ahmadi, Maryam; Quian Quiroga, Rodrigo

    2013-02-01

    We present an automatic denoising method based on the wavelet transform to obtain single trial evoked potentials. The method is based on the inter- and intra-scale variability of the wavelet coefficients and their deviations from baseline values. The performance of the method is tested with simulated event related potentials (ERPs) and with real visual and auditory ERPs. For the simulated data the presented method gives a significant improvement in the observation of single trial ERPs as well as in the estimation of their amplitudes and latencies, in comparison with a standard denoising technique (Donoho's thresholding) and in comparison with the noisy single trials. For the real data, the proposed method largely filters the spontaneous EEG activity, thus helping the identification of single trial visual and auditory ERPs. The proposed method provides a simple, automatic and fast tool that allows the study of single trial responses and their correlations with behavior.

  20. Stimulus-driven reorienting in the ventral frontoparietal attention network: the role of emotion

    Directory of Open Access Journals (Sweden)

    David Witt Frank

    2012-05-01

    Full Text Available Activity in the human temporoparietal junction and inferior frontal gyrus is hypothesized to underlie stimulus-driven, or bottom-up attention reorienting. Demanding tasks require focused attention, and as task difficulty increases, activity suppression in the ventral network correlates positively with task performance, an effect thought to reflect the gating of irrelevant cues. However, activation in these structures is elicited by a range of stimulus features and task demands that vary across multiple characteristics, complicating the interpretation of the functional role of this pathway. Consideration of several current studies suggests that, in addition to task difficulty, the motivational relevance or emotional intensity of distractor stimuli may supersede ongoing task priority, and evoke ventral network activation. Support for this possibility is offered from a review of recent reports, and the import of this perspective for models of attention reorienting are discussed.

  1. Performance Indexes: Similarities and Differences

    Directory of Open Access Journals (Sweden)

    André Machado Caldeira

    2013-06-01

    Full Text Available The investor of today is more rigorous on monitoring a financial assets portfolio. He no longer thinks only in terms of the expected return (one dimension, but in terms of risk-return (two dimensions. Thus new perception is more complex, since the risk measurement can vary according to anyone’s perception; some use the standard deviation for that, others disagree with this measure by proposing others. In addition to this difficulty, there is the problem of how to consider these two dimensions. The objective of this essay is to study the main performance indexes through an empirical study in order to verify the differences and similarities for some of the selected assets. One performance index proposed in Caldeira (2005 shall be included in this analysis.

  2. Semantically enabled image similarity search

    Science.gov (United States)

    Casterline, May V.; Emerick, Timothy; Sadeghi, Kolia; Gosse, C. A.; Bartlett, Brent; Casey, Jason

    2015-05-01

    Georeferenced data of various modalities are increasingly available for intelligence and commercial use, however effectively exploiting these sources demands a unified data space capable of capturing the unique contribution of each input. This work presents a suite of software tools for representing geospatial vector data and overhead imagery in a shared high-dimension vector or embedding" space that supports fused learning and similarity search across dissimilar modalities. While the approach is suitable for fusing arbitrary input types, including free text, the present work exploits the obvious but computationally difficult relationship between GIS and overhead imagery. GIS is comprised of temporally-smoothed but information-limited content of a GIS, while overhead imagery provides an information-rich but temporally-limited perspective. This processing framework includes some important extensions of concepts in literature but, more critically, presents a means to accomplish them as a unified framework at scale on commodity cloud architectures.

  3. SIMILARITIES AND DIFFERENCES BETWEEN COMPANIES

    Directory of Open Access Journals (Sweden)

    NAGY CRISTINA MIHAELA

    2015-05-01

    Full Text Available act: Similarities between the accounting of companies and territorial administrative units accounting are the following: organizing double entry accounting; accounting method both in terms of fundamental theoretical principles and specific practical tools. The differences between the accounting of companies and of territorial administrative units refer to: the accounting of territorial administrative units includes besides general accounting (financial also budgetary accounting, and the accounts system of the budgetary accounting is completely different from that of companies; financial statements of territorial administrative units to which leaders are not main authorizing officers are submitted to the hierarchically superior body (not at MPF; the accounts of territorial administrative units are opened at treasury and financial institutions, accounts at commercial banks being prohibited; equity accounts in territorial administrative units are structured into groups of funds; long term debts have a specific structure in territorial administrative units (internal local public debt and external local public debt.

  4. Features Based Text Similarity Detection

    CERN Document Server

    Kent, Chow Kok

    2010-01-01

    As the Internet help us cross cultural border by providing different information, plagiarism issue is bound to arise. As a result, plagiarism detection becomes more demanding in overcoming this issue. Different plagiarism detection tools have been developed based on various detection techniques. Nowadays, fingerprint matching technique plays an important role in those detection tools. However, in handling some large content articles, there are some weaknesses in fingerprint matching technique especially in space and time consumption issue. In this paper, we propose a new approach to detect plagiarism which integrates the use of fingerprint matching technique with four key features to assist in the detection process. These proposed features are capable to choose the main point or key sentence in the articles to be compared. Those selected sentence will be undergo the fingerprint matching process in order to detect the similarity between the sentences. Hence, time and space usage for the comparison process is r...

  5. Abolishing and Establishing Operation Analyses of Social Attention as Positive Reinforcement for Problem Behavior

    Science.gov (United States)

    McGinnis, Molly A.; Houchins-Juarez, Nealetta; McDaniel, Jill L.; Kennedy, Craig H.

    2010-01-01

    Three participants whose problem behavior was maintained by contingent attention were exposed to 45-min presessions in which attention was withheld, provided on a fixed-time (FT) 15-s schedule, or provided on an FT 120-s schedule. Following each presession, participants were then tested in a 15-min session similar to the social attention condition…

  6. Postural threat influences vestibular-evoked muscular responses.

    Science.gov (United States)

    Lim, Shannon B; Cleworth, Taylor W; Horslen, Brian C; Blouin, Jean-Sébastien; Inglis, J Timothy; Carpenter, Mark G

    2017-02-01

    Standing balance is significantly influenced by postural threat. While this effect has been well established, the underlying mechanisms of the effect are less understood. The involvement of the vestibular system is under current debate, and recent studies that investigated the effects of height-induced postural threat on vestibular-evoked responses provide conflicting results based on kinetic (Horslen BC, Dakin CJ, Inglis JT, Blouin JS, Carpenter MG. J Physiol 592: 3671-3685, 2014) and kinematic (Osler CJ, Tersteeg MC, Reynolds RF, Loram ID. Eur J Neurosci 38: 3239-3247, 2013) data. We examined the effect of threat of perturbation, a different form of postural threat, on coupling (cross-correlation, coherence, and gain) of the vestibulo-muscular relationship in 25 participants who maintained standing balance. In the "No-Threat" conditions, participants stood quietly on a stable surface. In the "Threat" condition, participants' balance was threatened with unpredictable mediolateral support surface tilts. Quiet standing immediately before the surface tilts was compared to an equivalent time from the No-Threat conditions. Surface EMG was recorded from bilateral trunk, hip, and leg muscles. Hip and leg muscles exhibited significant increases in peak cross-correlation amplitudes, coherence, and gain (1.23-2.66×) in the Threat condition compared with No-Threat conditions, and significant correlations were observed between threat-related changes in physiological arousal and medium-latency peak cross-correlation amplitude in medial gastrocnemius (r = 0.408) muscles. These findings show a clear threat effect on vestibular-evoked responses in muscles in the lower body, with less robust effects of threat on trunk muscles. Combined with previous work, the present results can provide insight into observed changes during balance control in threatening situations.

  7. Transient visual evoked neuromagnetic responses: Identification of multiple sources

    Energy Technology Data Exchange (ETDEWEB)

    Aine, C.; George, J.; Medvick, P.; Flynn, E.; Bodis-Wollner, I.; Supek, S.

    1989-01-01

    Neuromagnetic measurements and associated modeling procedures must be able to resolve multiple sources in order to localize and accurately characterize the generators of visual evoked neuromagnetic activity. Workers have identified at least 11 areas in the macaque, throughout occipital, parietal, and temporal cortex, which are primarily or entirely visual in function. The surface area of the human occipital lobe is estimated to be 150--250cm. Primary visual cortex covers approximately 26cm/sup 2/ while secondary visual areas comprise the remaining area. For evoked response amplitudes typical of human MEG data, one report estimates that a two-dipole field may be statistically distinguishable from that of a single dipole when the separation is greater than 1--2 cm. Given the estimated expanse of cortex devoted to visual processes, along with this estimate of resolution limits it is likely that MEG can resolve sources associated with activity in multiple visual areas. Researchers have noted evidence for the existence of multiple sources when presenting visual stimuli in a half field; however, they did not attempt to localize them. We have examined numerous human MEG field patterns resulting from different visual field placements of a small sinusoidal grating which suggest the existence of multiple sources. The analyses we have utilized for resolving multiple sources in these studies differ depending on whether there was evidence of (1) synchronous activation of two spatially discrete sources or (2) two discrete asynchronous sources. In some cases we have observed field patterns which appear to be adequately explained by a single source changing its orientation and location across time. 4 refs., 2 figs.

  8. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

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    Lizeth H Sloot

    Full Text Available Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms. Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally

  9. Brainstem auditory-evoked potentials in two meditative mental states

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    Kumar Sanjay

    2010-01-01

    Full Text Available Context: Practicing mental repetition of "OM" has been shown to cause significant changes in the middle latency auditory-evoked potentials, which suggests that it facilitates the neural activity at the mesencephalic or diencephalic levels. Aims: The aim of the study was to study the brainstem auditory-evoked potentials (BAEP in two meditation states based on consciousness, viz. dharana, and dhyana. Materials and Methods: Thirty subjects were selected, with ages ranging from 20 to 55 years (M=29.1; ±SD=6.5 years who had a minimum of 6 months experience in meditating "OM". Each subject was assessed in four sessions, i.e. two meditation and two control sessions. The two control sessions were: (i ekagrata, i.e. single-topic lecture on meditation and (ii cancalata, i.e. non-targeted thinking. The two meditation sessions were: (i dharana, i.e. focusing on the symbol "OM" and (ii dhyana, i.e. effortless single-thought state "OM". All four sessions were recorded on four different days and consisted of three states, i.e. pre, during and post. Results: The present results showed that the wave V peak latency significantly increased in cancalata, ekagrata and dharana, but no change occurred during the dhyana session. Conclusions: These results suggested that information transmission along the auditory pathway is delayed during cancalata, ekagrata and dharana, but there is no change during dhyana. It may be said that auditory information transmission was delayed at the inferior collicular level as the wave V corresponds to the tectum.

  10. Prestimulation phase predicts the TMS-evoked response.

    Science.gov (United States)

    Kundu, Bornali; Johnson, Jeffrey S; Postle, Bradley R

    2014-10-15

    Prestimulation oscillatory phase and power in particular frequency bands predict perception of at-threshold visual stimuli and of transcranial magnetic stimulation (TMS)-induced phosphenes. These effects may be due to changes in cortical excitability, such that certain ranges of power and/or phase values result in a state in which a particular brain area is more receptive to input, thereby biasing behavior. However, the effects of trial-by-trial fluctuations in phase and power of ongoing oscillations on the brain's electrical response to TMS itself have thus far not been addressed. The present study adopts a combined TMS and electroencepalography (EEG) approach to determine whether the TMS-evoked response is sensitive to momentary fluctuations in prestimulation phase and/or power in different frequency bands. Specifically, TMS was applied to superior parietal lobule while subjects performed a short-term memory task. Results showed that the prestimulation phase, particularly within the beta (15-25 Hz) band, predicted pulse-by-pulse variations in the global mean field amplitude. No such relationship was observed between prestimulation power and the global mean field amplitude. Furthermore, TMS-evoked power in the beta band fluctuated with prestimulation phase in the beta band in a manner that differed from spontaneous brain activity. These effects were observed in areas at and distal to the stimulation site. Together, these results confirm the idea that fluctuating phase of ongoing neuronal oscillations create "windows of excitability" in the brain, and they give insight into how TMS interacts with ongoing brain activity on a pulse-by-pulse basis.

  11. Distributed Efficient Similarity Search Mechanism in Wireless Sensor Networks

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    Khandakar Ahmed

    2015-03-01

    Full Text Available The Wireless Sensor Network similarity search problem has received considerable research attention due to sensor hardware imprecision and environmental parameter variations. Most of the state-of-the-art distributed data centric storage (DCS schemes lack optimization for similarity queries of events. In this paper, a DCS scheme with metric based similarity searching (DCSMSS is proposed. DCSMSS takes motivation from vector distance index, called iDistance, in order to transform the issue of similarity searching into the problem of an interval search in one dimension. In addition, a sector based distance routing algorithm is used to efficiently route messages. Extensive simulation results reveal that DCSMSS is highly efficient and significantly outperforms previous approaches in processing similarity search queries.

  12. Alcohol Effects on the P2 component of Auditory Evoked Potentials

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    OSCAR H. HERNÁNDEZ

    2014-03-01

    Full Text Available This is a second part of a research aimed to study the effects of alcohol on the electrophysiological processes in student volunteers. The first part showed that alcohol slowed the Omitted Stimulus Potential (OSP. This work studied the ethanol effects on the parameters (i.e. rate of rise, amplitude and peak latency of the P2 component of the evoked potentials (EPs yielded by trains of auditory stimuli. It is hypothesized here that if P2 and OSP waves share some common neural processes then alcohol should also affect these specific parameters. A dose of 0.8 g/kg of alcohol or a placebo (0 g/kg was administered to two groups of 15 young men who were tested before and again after treatment. The pre-post treatment change in each of the measurements was used to assess the treatment effects. The results showed that compared to placebo, alcohol slowed the P2 rise rate and reduced its amplitude, with no effects on peak latency. The rise rate is more sensitive to alcohol but more resistant to the adaptation process. Alcohol resembles the response inhibition model acting against the adaptation. The rise rate of the P2 and the OSP waves are affected by alcohol in a similar fashion, suggesting similar neural generative mechanisms.

  13. Neural mechanisms of intermodal sustained selective attention with concurrently presented auditory and visual stimuli

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    Katja Saupe

    2009-11-01

    Full Text Available We investigated intermodal attention effects on the auditory steady-state response (ASSR and the steady-state visual evoked potential (SSVEP. For this purpose, 40 Hz amplitude modulated tones and a stream of flickering (7.5 Hz random letters were presented concurrently. By means of an auditory or visual target detection task, participants’ attention was directed to the respective modality for several seconds. Attention to the auditory stream led to a significant enhancement of the ASSR compared to when the visual stream was attended. This attentional modulation was located mainly in the right superior temporal gyrus. Vice versa, attention to the visual stream especially increased the second harmonic response of the SSVEP. This modulation was focused in the inferior occipital and lateral occipitotemporal gyrus of both hemispheres. To the best of our knowledge, this is the first demonstration of amplitude modulation of the ASSR and the SSVEP by intermodal sustained attention. Our results open a new avenue of research to understand the basic neural mechanisms of intermodal attention in the human brain.

  14. Conduction velocity of the human spinothalamic tract as assessed by laser evoked potentials

    DEFF Research Database (Denmark)

    Cruccu, G.; Iannetti, G. D.; Agostino, R.

    2000-01-01

    To study the conduction velocity of the spinothalamic tract (STT) we delivered CO2 laser pulses, evoking pinprick sensations, to the skin overlying the vertebral spinous processes at different spinal levels from C5 to T10 and recorded evoked potentials (LEPs) in 15 healthy human subjects...

  15. The effect of changes in perilymphatic K+ on the vestibular evoked potential in the guinea pig

    NARCIS (Netherlands)

    Kingma, C. M.; Wit, H. P.

    2010-01-01

    To investigate the effect on the functioning of the vestibular system of a rupture of Reissner's membrane, artificial endolymph was injected in scala media of ten guinea pigs and vestibular evoked potentials (VsEPs), evoked by vertical acceleration pulses, were measured. Directly after injection of

  16. A simple model for the generation of the vestibular evoked myogenic potential (VEMP)

    NARCIS (Netherlands)

    Wit, HP; Kingma, CM

    2006-01-01

    Objective: To describe the mechanism by which the vestibular evoked myogenic potential is generated. Methods: Vestibular evoked myogenic potential generation is modeled by adding a large number of muscle motor unit action potentials. These action potentials occur randomly in time along a 100 ms long

  17. Pay Attention! Demonstrating the Role of Attention in Learning.

    Science.gov (United States)

    Larsen, Janet D.

    1991-01-01

    Describes a demonstration to illustrate the importance of knowing what is supposed to be learned before studying begins. Suggests that the exercise may be used to show the basic elements of a scientific experiment. Explains that attention's effect upon memory is shown by students' tendency to remember best what they are told to remember. (DK)

  18. Timing attention : Cuing target onset interval attenuates the attentional blink

    NARCIS (Netherlands)

    Martens, S; Johnson, A

    2005-01-01

    Three experiments tested whether the attentional blink (AB; a deficit in reporting the second of two targets when it occurs 200-500 msec after the first) can be attenuated by providing information about the target onset asynchrony (TOA) of the second target relative to the first. Blocking the TOA di

  19. Attention Deficits, Attention-Deficit Hyperactivity Disorder, and Intellectual Disabilities

    Science.gov (United States)

    Deutsch, Curtis K.; Dube, William V.; McIlvane, William J.

    2008-01-01

    Attention-Deficit Hyperactivity Disorder (ADHD) and its earlier nosologic classifications have been extensively investigated since the 1960s, with PubMed listings alone exceeding 13,000 entries. Strides have been made in the diagnosis and treatment of ADHD in individuals with intellectual function in the normal range, as described in companion…

  20. Now, Pay Attention! The Effects of Instruction on Children's Attention

    Science.gov (United States)

    Kannass, Kathleen N.; Colombo, John; Wyss, Nancy

    2010-01-01

    We investigated the effects of instructions to "stay on task" on preschoolers' attention and cognitive performance in the face of either incomprehensible or comprehensible distraction. Three- and 4-year-olds completed problem-solving tasks while a distracting event played continuously in the background under conditions of (a) no instruction, (b)…

  1. Attention, interpretation, identity and narcissism.

    Science.gov (United States)

    Boschan, P J

    1989-01-01

    Disturbances of the analyst's attention and interferences in the interpretation process are correlated with narcissistic resistances (NR). Interpretation is considered, not only as verbal communication about the patient's unconscious contents, but also as the analyst's instrument to re-establish subject-object discrimination, altered by the archaic aspects of transference. Different types of NR lead to different transference configurations, with specific patterns of involvement of the analyst. The author describes the characteristics of the object relationships in patients with NR predominance and some genetic hypotheses are proposed. The analyst's tolerance of primitive mental functioning, his permeability and capacity to sustain evenly suspended attention are correlated; a comparison is drawn with some neurophysiological findings about attention. Finally, the importance of temporality in these functions is discussed, with some thoughts regarding its role in the outcome of the analyses mentioned by Freud in 'Analysis terminable and interminable'.

  2. Components of Attention in Synesthesia

    DEFF Research Database (Denmark)

    Sørensen, Thomas Alrik; Nordfang, Maria; Pedersen, Michael Nygaard

    2013-01-01

    One of the most common forms of synesthesia is between colors and graphemes (Colizoli, Murre, & Rouw, 2012). Numerous studies have investigated different aspects of attention and synesthesia, e.g. effects of Stroop-like interference by colors that are incongruent with the synesthetic experience....... Here we attempt to isolate how speci¿ c components of attention are affected by grapheme-color synesthesia. Eight carefully screened healthy participants with synesthesia reported the letters in brie¿ y presented, post-masked arrays of letters and digits. On half the trials, the letters and digits were...... presented in colors congruent with the synesthetic experience. On the other half of the trials, the letters and digits were presented in colors that were incongruent with the synesthetic experience. Components of attention were estimated separately for congruent and incongruent trials by ¿ tting the data...

  3. Supramodal Executive Control of Attention

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    ALFREDO eSPAGNA

    2015-02-01

    Full Text Available The human attentional system can be subdivided into three functional networks of alerting, orienting, and executive control. Although these networks have been extensively studied in the visuospatial modality, whether the same mechanisms are deployed across different sensory modalities remains unclear. In this study we used the attention network test for visuospatial modality, in addition to two auditory variants with spatial and frequency manipulations to examine cross-modal correlations between network functions. Results showed that among the visual and auditory tasks the effects of executive control, but not effects of alerting and orienting were significantly correlated. These findings suggest that while alerting and orienting functions rely more upon modality specific processes, the executive control of attention coordinates complex behavior via supramodal mechanisms.

  4. Attentional modulation of emotional conflict processing with flanker tasks.

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    Pingyan Zhou

    Full Text Available Emotion processing has been shown to acquire priority by biasing allocation of attentional resources. Aversive images or fearful expressions are processed quickly and automatically. Many existing findings suggested that processing of emotional information was pre-attentive, largely immune from attentional control. Other studies argued that attention gated the processing of emotion. To tackle this controversy, the current study examined whether and to what degrees attention modulated processing of emotion using a stimulus-response-compatibility (SRC paradigm. We conducted two flanker experiments using color scale faces in neutral expressions or gray scale faces in emotional expressions. We found SRC effects for all three dimensions (color, gender, and emotion and SRC effects were larger when the conflicts were task relevant than when they were task irrelevant, suggesting that conflict processing of emotion was modulated by attention, similar to those of color and face identity (gender. However, task modulation on color SRC effect was significantly greater than that on gender or emotion SRC effect, indicating that processing of salient information was modulated by attention to a lesser degree than processing of non-emotional stimuli. We proposed that emotion processing can be influenced by attentional control, but at the same time salience of emotional information may bias toward bottom-up processing, rendering less top-down modulation than that on non-emotional stimuli.

  5. Attentional modulation of emotional conflict processing with flanker tasks.

    Science.gov (United States)

    Zhou, Pingyan; Liu, Xun

    2013-01-01

    Emotion processing has been shown to acquire priority by biasing allocation of attentional resources. Aversive images or fearful expressions are processed quickly and automatically. Many existing findings suggested that processing of emotional information was pre-attentive, largely immune from attentional control. Other studies argued that attention gated the processing of emotion. To tackle this controversy, the current study examined whether and to what degrees attention modulated processing of emotion using a stimulus-response-compatibility (SRC) paradigm. We conducted two flanker experiments using color scale faces in neutral expressions or gray scale faces in emotional expressions. We found SRC effects for all three dimensions (color, gender, and emotion) and SRC effects were larger when the conflicts were task relevant than when they were task irrelevant, suggesting that conflict processing of emotion was modulated by attention, similar to those of color and face identity (gender). However, task modulation on color SRC effect was significantly greater than that on gender or emotion SRC effect, indicating that processing of salient information was modulated by attention to a lesser degree than processing of non-emotional stimuli. We proposed that emotion processing can be influenced by attentional control, but at the same time salience of emotional information may bias toward bottom-up processing, rendering less top-down modulation than that on non-emotional stimuli.

  6. Feature-based attentional modulation of orientation perception in somatosensation

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    Meike Annika Schweisfurth

    2014-07-01

    Full Text Available In a reaction time study of human tactile orientation detection the effects of spatial attention and feature-based attention were investigated. Subjects had to give speeded responses to target orientations (parallel and orthogonal to the finger axis in a random stream of oblique tactile distractor orientations presented to their index and ring fingers. Before each block of trials, subjects received a tactile cue at one finger. By manipulating the validity of this cue with respect to its location and orientation (feature, we provided an incentive to subjects to attend spatially to the cued location and only there to the cued orientation. Subjects showed quicker responses to parallel compared to orthogonal targets, pointing to an orientation anisotropy in sensory processing. Also, faster reaction times were observed in location-matched trials, i.e. when targets appeared on the cued finger, representing a perceptual benefit of spatial attention. Most importantly, reaction times were shorter to orientations matching the cue, both at the cued and at the uncued location, documenting a global enhancement of tactile sensation by feature-based attention. This is the first report of a perceptual benefit of feature-based attention outside the spatial focus of attention in somatosensory perception. The similarity to effects of feature-based attention in visual perception supports the notion of matching attentional mechanisms across sensory domains.

  7. Mindful Movement and Skilled Attention

    Directory of Open Access Journals (Sweden)

    Dav eClark

    2015-06-01

    Full Text Available Bodily movement has long been employed as a foundation for cultivating mental skills such as attention, self-control or mindfulness, with recent studies documenting the positive impacts of mindful movement training, such as yoga and tai chi. A parallel mind-body connection has also been observed in many developmental disorders. We elaborate a spectrum of mindfulness by considering ADHD, in which deficient motor control correlates with impaired (disinhibited behavioral control contributing to defining features of excessive distractibility and impulsivity. These data provide evidence for an important axis of variation for wellbeing, in which skillful cognitive control covaries with a capacity for skillful movement. We review empirical and theoretical literature on attention, cognitive control, mind wandering, mindfulness and skill learning, endorsing a model of skilled attention in which motor plans, attention, and executive goals are seen as mutually co-defining aspects of skilled behavior that are linked by reciprocal inhibitory and excitatory connections. Thus, any movement training should engage higher-order inhibition and selection and develop a repertoire of rehearsed procedures that coordinate goals, attention and motor plans. However, we propose that mindful movement practice may improve the functional quality of rehearsed procedures, cultivating a transferrable skill of attention. We adopt Langer’s spectrum of mindful learning that spans from mindlessness to engagement with the details of the present task and contrast this with the mental attitudes cultivated in standard mindfulness meditation. We particularly follow Feldenkrais’ suggestion that mindful learning of skills for organizing the body in movement might transfer to other forms of mental activity. The results of mindful movement training should be observed in multiple complementary measures, and may have tremendous potential benefit for individuals with ADHD and other

  8. Mindful movement and skilled attention.

    Science.gov (United States)

    Clark, Dav; Schumann, Frank; Mostofsky, Stewart H

    2015-01-01

    Bodily movement has long been employed as a foundation for cultivating mental skills such as attention, self-control or mindfulness, with recent studies documenting the positive impacts of mindful movement training, such as yoga and tai chi. A parallel "mind-body connection" has also been observed in many developmental disorders. We elaborate a spectrum of mindfulness by considering ADHD, in which deficient motor control correlates with impaired (disinhibited) behavioral control contributing to defining features of excessive distractibility and impulsivity. These data provide evidence for an important axis of variation for wellbeing, in which skillful cognitive control covaries with a capacity for skillful movement. We review empirical and theoretical literature on attention, cognitive control, mind wandering, mindfulness and skill learning, endorsing a model of skilled attention in which motor plans, attention, and executive goals are seen as mutually co-defining aspects of skilled behavior that are linked by reciprocal inhibitory and excitatory connections. Thus, any movement training should engage "higher-order" inhibition and selection and develop a repertoire of rehearsed procedures that coordinate goals, attention and motor plans. However, we propose that mindful movement practice may improve the functional quality of rehearsed procedures, cultivating a transferrable skill of attention. We adopt Langer's spectrum of mindful learning that spans from "mindlessness" to engagement with the details of the present task and contrast this with the mental attitudes cultivated in standard mindfulness meditation. We particularly follow Feldenkrais' suggestion that mindful learning of skills for organizing the body in movement might transfer to other forms of mental activity. The results of mindful movement training should be observed in multiple complementary measures, and may have tremendous potential benefit for individuals with ADHD and other populations.

  9. Selective Attention in the Learning Disabled Child.

    Science.gov (United States)

    Wooten, Ann M.

    The paper reviews literature relating to selective attention in the learning disabled child. Three processes related to the concept of selective attention (as proposed by D. Berlyne) are discussed: attention in learning, attention in remembering, and attention in performance. It is pointed out that verbal mediation, the use of verbal labels to…

  10. Properties of rectified averaging of an evoked-type signal: theory and application to the vestibular-evoked myogenic potential.

    Science.gov (United States)

    Colebatch, J G

    2009-11-01

    The properties of rectified averages were investigated using the VEMP (vestibular-evoked myogenic potential) as an example of an evoked-type response. Recordings were made of surface EMG from the sternocleidomastoid (SCM) muscles of six volunteers, unstimulated, at different levels of tonic activation and then in response to clicks of different intensities. The stochastic properties of the surface EMG recorded were shown to be well modelled using a zero mean normal distribution with a standard deviation equivalent to the mean RMS (root mean squared) value (mean residual error variance 0.87%). Assuming a normal distribution, equations were derived for the expected value of both the rectified and RMS average with the addition of constant waveforms of different sizes. A simulation using recorded EMG and added sine waves of different amplitudes demonstrated that the equations predicted the rectified averages accurately. It also confirmed the importance of the relative amplitude of the added signal in determining whether it was detected using rectified averages. The same equations were then applied to actual data consisting of VEMPs of different relative amplitudes recorded from the volunteers. Whilst the signal-to-noise ratio (measured by corrected amplitude) was a major determinant of the nature of the rectified average, consistent deviations were detected between the predicted and actual rectified averages. Deviations from predicted values indicated that the VEMP did not behave simply like a constant signal added to tonic background EMG. A more complicated model, which included temporal jitter as well as inhibition of background EMG during the VEMP, was required to fit the physiological recordings. Rectified averages are sensitive to physiological properties, which are not apparent when using unrectified averages alone. Awareness of the properties of rectified averages should improve their interpretation.

  11. Rhythmic patterns evoked in locust leg motor neurons by the muscarinic agonist pilocarpine.

    Science.gov (United States)

    Ryckebusch, S; Laurent, G

    1993-05-01

    1. When an isolated metathoracic ganglion of the locust was superfused with the muscarinic cholinergic agonist pilocarpine, rhythmic activity was induced in leg motor neurons. The frequency of this induced rhythm increased approximately linearly from 0 to 0.2 Hz with concentrations of pilocarpine from 10(-5) to 10(-4) M. Rhythmic activity evoked by pilocarpine could be completely and reversibly blocked by 3 x 10(-5) M atropine, but was unaffected by 10(-4) M d-tubocurarine. 2. For each hemiganglion, the observed rhythm was characterized by two main phases: a levator phase, during which the anterior coxal rotator, levators of the trochanter, flexors of the tibia, and common inhibitory motor neurons were active; and a depressor phase, during which depressors of the trochanter, extensors of the tibia, and depressors of the tarsus were active. Activity in depressors of the trochanter followed the activity of the levators of the trochanter with a short, constant interburst latency. Activity in the levator of the tarsus spanned both phases. 3. The levator phase was short compared with the period (0.5-2 s, or 10-20% of the period) and did not depend on the period. The interval between the end of a levator burst and the beginning of the following one thus increased with cycle period. The depressor phase was more variable, and was usually shorter than the interval between successive levator bursts. 4. Motor neurons in a same pool often received common discrete synaptic potentials (e.g., levators of trochanter or extensors of tibia), suggesting common drive during the rhythm. Coactive motor neurons on opposite sides (such as left trochanteral depressors and right trochanteral levators), however, did not share obvious common postsynaptic potentials. Depolarization of a pool of motor neurons during its phase of activity was generally accompanied by hyperpolarization of its antagonist(s) on the same side. 5. Rhythmic activity was generally evoked in both hemiganglia of the

  12. Activation of NTS A(1) adenosine receptors inhibits regional sympathetic responses evoked by activation of cardiopulmonary chemoreflex.

    Science.gov (United States)

    Ichinose, Tomoko K; Minic, Zeljka; Li, Cailian; O'Leary, Donal S; Scislo, Tadeusz J

    2012-09-01

    Previously we have shown that adenosine operating via the A(1) receptor subtype may inhibit glutamatergic transmission in the baroreflex arc within the nucleus of the solitary tract (NTS) and differentially increase renal (RSNA), preganglionic adrenal (pre-ASNA), and lumbar (LSNA) sympathetic nerve activity (ASNA>RSNA≥LSNA). Since the cardiopulmonary chemoreflex and the arterial baroreflex are mediated via similar medullary pathways, and glutamate is a primary transmitter in both pathways, it is likely that adenosine operating via A(1) receptors in the NTS may differentially inhibit regional sympathetic responses evoked by activation of cardiopulmonary chemoreceptors. Therefore, in urethane-chloralose-anesthetized rats (n = 37) we compared regional sympathoinhibition evoked by the cardiopulmonary chemoreflex (activated with right atrial injections of serotonin 5HT(3) receptor agonist phenylbiguanide, PBG, 1-8 μg/kg) before and after selective stimulation of NTS A(1) adenosine receptors [microinjections of N(6)-cyclopentyl adenosine (CPA), 0.033-330 pmol/50 nl]. Activation of cardiopulmonary chemoreceptors evoked differential, dose-dependent sympathoinhibition (RSNA>ASNA>LSNA), and decreases in arterial pressure and heart rate. These differential sympathetic responses were uniformly attenuated in dose-dependent manner by microinjections of CPA into the NTS. Volume control (n = 11) and blockade of adenosine receptor subtypes in the NTS via 8-(p-sulfophenyl)theophylline (8-SPT, 1 nmol in 100 nl) (n = 9) did not affect the reflex responses. We conclude that activation of NTS A(1) adenosine receptors uniformly inhibits neural and cardiovascular cardiopulmonary chemoreflex responses. A(1) adenosine receptors have no tonic modulatory effect on this reflex under normal conditions. However, when adenosine is released into the NTS (i.e., during stress or severe hypotension/ischemia), it may serve as negative feedback regulator for depressor and sympathoinhibitory reflexes

  13. Attentional episodes in visual perception

    NARCIS (Netherlands)

    Wyble, Brad; Potter, Mary C.; Bowman, Howard; Nieuwenstein, Mark

    2011-01-01

    Is one's temporal perception of the world truly as seamless as it appears? This article presents a computationally motivated theory suggesting that visual attention samples information from temporal episodes (episodic simultaneous type/serial token model; Wyble, Bowman, & Nieuwenstein, 2009). Breaks

  14. Thinking of God Moves Attention

    Science.gov (United States)

    Chasteen, Alison L.; Burdzy, Donna C.; Pratt, Jay

    2010-01-01

    The concepts of God and Devil are well known across many cultures and religions, and often involve spatial metaphors, but it is not well known if our mental representations of these concepts affect visual cognition. To examine if exposure to divine concepts produces shifts of attention, participants completed a target detection task in which they…

  15. The Mechanisms of Involuntary Attention

    Science.gov (United States)

    Prinzmetal, William; Ha, Ruby; Khani, Aniss

    2010-01-01

    We tested 3 mechanisms of involuntary attention: (1) a perceptual enhancement mechanism, (2) a response-decision mechanism, and (3) a serial-search mechanism. Experiment 1 used a response deadline technique to compare the perceptual enhancement and the decision mechanisms and found evidence consistent with the decision mechanism. Experiment 2 used…

  16. Attention: A Machine Learning Perspective

    DEFF Research Database (Denmark)

    Hansen, Lars Kai

    2012-01-01

    We review a statistical machine learning model of top-down task driven attention based on the notion of ‘gist’. In this framework we consider the task to be represented as a classification problem with two sets of features — a gist of coarse grained global features and a larger set of low...

  17. Attention and the Testing Effect

    Science.gov (United States)

    Mulligan, Neil W.; Picklesimer, Milton

    2016-01-01

    Memory retrieval often enhances still later memory as evidenced by the testing effect. Divided attention (DA) is known to produce different effects on encoding and retrieval, substantially disrupting the former and often producing little effect on the latter. The present experiments examine whether the mnemonic consequences of retrieval are…

  18. Attentional bias in math anxiety

    Science.gov (United States)

    Rubinsten, Orly; Eidlin, Hili; Wohl, Hadas; Akibli, Orly

    2015-01-01

    Cognitive theory from the field of general anxiety suggests that the tendency to display attentional bias toward negative information results in anxiety. Accordingly, the current study aims to investigate whether attentional bias is involved in math anxiety (MA) as well (i.e., a persistent negative reaction to math). Twenty seven participants (14 with high levels of MA and 13 with low levels of MA) were presented with a novel computerized numerical version of the well established dot probe task. One of six types of prime stimuli, either math related or typically neutral, was presented on one side of a computer screen. The prime was preceded by a probe (either one or two asterisks) that appeared in either the prime or the opposite location. Participants had to discriminate probe identity (one or two asterisks). Math anxious individuals reacted faster when the probe was at the location of the numerical related stimuli. This suggests the existence of attentional bias in MA. That is, for math anxious individuals, the cognitive system selectively favored the processing of emotionally negative information (i.e., math related words). These findings suggest that attentional bias is linked to unduly intense MA symptoms. PMID:26528208

  19. Attentional Bias in Math Anxiety

    Directory of Open Access Journals (Sweden)

    Orly eRubinsten

    2015-10-01

    Full Text Available Cognitive theory from the field of general anxiety suggests that the tendency to display attentional bias toward negative information results in anxiety. Accordingly, the current study aims to investigate whether attentional bias is involved in math anxiety as well (i.e., a persistent negative reaction to math. Twenty seven participants (14 with high levels of math anxiety and 13 with low levels of math anxiety were presented with a novel computerized numerical version of the well established dot probe task. One of 6 types of prime stimuli, either math related or typically neutral, were presented on one side of a computer screen. The prime was preceded by a probe (either one or two asterisks that appeared in either the prime or the opposite location. Participants had to discriminate probe identity (one or two asterisks. Math anxious individuals reacted faster when the probe was at the location of the numerical related stimuli. This suggests the existence of attentional bias in math anxiety. That is, for math anxious individuals, the cognitive system selectively favored the processing of emotionally negative information (i.e., math related words. These findings suggest that attentional bias is linked to unduly intense math anxiety symptoms.

  20. Dyscalculia and Attention Deficit Subtypes

    OpenAIRE

    1999-01-01

    The association of specific academic deficits with attention deficit disorder (ADD) subtypes was determined in 20 students (ages 8-12) with ADD with hyperactivity (ADD/H) compared to 20 with ADD without hyperactivity (ADD/noH), at the Department of Educational Psychology, University of Texas at Austin, TX.

  1. Attention Deficit Hyperactivity Disorder (ADHD)

    Centers for Disease Control (CDC) Podcasts

    2014-04-10

    This podcast discusses Attention Deficit Hyperactivity Disorder, or ADHD, the most common behavioral disorder in children. Learn about symptoms, risk factors, and treatment.  Created: 4/10/2014 by National Center on Birth Defects and Developmental Disabilities (NCBDDD).   Date Released: 5/7/2014.

  2. Perception and Attention for Visualization

    Science.gov (United States)

    Haroz, Steve

    2013-01-01

    This work examines how a better understanding of visual perception and attention can impact visualization design. In a collection of studies, I explore how different levels of the visual system can measurably affect a variety of visualization metrics. The results show that expert preference, user performance, and even computational performance are…

  3. Attention to the Second Language

    Science.gov (United States)

    Wickens, Christopher D.

    2007-01-01

    Attention to a task, and the language it requires to be performed, can be described in relation to two theoretical models which have prompted research into the effects of task demands on learning and performance outside the field of second language acquisition (SLA). These are the SEEV (selection, effort, expectancy and value) model of selective…

  4. Attentional bias in math anxiety.

    Science.gov (United States)

    Rubinsten, Orly; Eidlin, Hili; Wohl, Hadas; Akibli, Orly

    2015-01-01

    Cognitive theory from the field of general anxiety suggests that the tendency to display attentional bias toward negative information results in anxiety. Accordingly, the current study aims to investigate whether attentional bias is involved in math anxiety (MA) as well (i.e., a persistent negative reaction to math). Twenty seven participants (14 with high levels of MA and 13 with low levels of MA) were presented with a novel computerized numerical version of the well established dot probe task. One of six types of prime stimuli, either math related or typically neutral, was presented on one side of a computer screen. The prime was preceded by a probe (either one or two asterisks) that appeared in either the prime or the opposite location. Participants had to discriminate probe identity (one or two asterisks). Math anxious individuals reacted faster when the probe was at the location of the numerical related stimuli. This suggests the existence of attentional bias in MA. That is, for math anxious individuals, the cognitive system selectively favored the processing of emotionally negative information (i.e., math related words). These findings suggest that attentional bias is linked to unduly intense MA symptoms.

  5. Spatially pooled contrast responses predict neural and perceptual similarity of naturalistic image categories.

    Directory of Open Access Journals (Sweden)

    Iris I A Groen

    Full Text Available The visual world is complex and continuously changing. Yet, our brain transforms patterns of light falling on our retina into a coherent percept within a few hundred milliseconds. Possibly, low-level neural responses already carry substantial information to facilitate rapid characterization of the visual input. Here, we computationally estimated low-level contrast responses to computer-generated naturalistic images, and tested whether spatial pooling of these responses could predict image similarity at the neural and behavioral level. Using EEG, we show that statistics derived from pooled responses explain a large amount of variance between single-image evoked potentials (ERPs in individual subjects. Dissimilarity analysis on multi-electrode ERPs demonstrated that large differences between images in pooled response statistics are predictive of more dissimilar patterns of evoked activity, whereas images with little difference in statistics give rise to highly similar evoked activity patterns. In a separate behavioral experiment, images with large differences in statistics were judged as different categories, whereas images with little differences were confused. These findings suggest that statistics derived from low-level contrast responses can be extracted in early visual processing and can be relevant for rapid judgment of visual similarity. We compared our results with two other, well- known contrast statistics: Fourier power spectra and higher-order properties of contrast distributions (skewness and kurtosis. Interestingly, whereas these statistics allow for accurate image categorization, they do not predict ERP response patterns or behavioral categorization confusions. These converging computational, neural and behavioral results suggest that statistics of pooled contrast responses contain information that corresponds with perceived visual similarity in a rapid, low-level categorization task.

  6. Faststats: Attention Deficit Hyperactivity Disorder (ADHD)

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    ... this? Submit What's this? Submit Button NCHS Home Attention Deficit Hyperactivity Disorder (ADHD)* Recommend on Facebook Tweet Share Compartir Data ... attention deficit disorder (ADD)" is used rather than "attention deficit hyperactivity disorder (ADHD)" in some data sources. More data Association ...

  7. Human treadmill walking needs attention

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    Daniel Olivier

    2006-08-01

    Full Text Available Abstract Background The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor task. Varying the level of difficulty of the reaction time (RT task is used to verify the priority of allocation of attentional resources. Methods 11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration. Results Gait cycle duration was unchanged (p > 0.05 by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p 0.05 was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance. Conclusion We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.

  8. Influence of visual angle on pattern reversal visual evoked potentials

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    Ruchi Kothari

    2014-01-01

    Full Text Available Purpose: The aim of this study was to find whether the visual evoked potential (VEP latencies and amplitude are altered with different visual angles in healthy adult volunteers or not and to determine the visual angle which is the optimum and most appropriate among a wide range of check sizes for the reliable interpretation of pattern reversal VEPs (PRVEPs. Materials and Methods: The present study was conducted on 40 healthy volunteers. The subjects were divided into two groups. One group consisted of 20 individuals (nine males and 11 females in the age range of 25-57 years and they were exposed to checks subtending a visual angle of 90, 120, and 180 minutes of arc. Another group comprised of 20 individuals (10 males and 10 females in the age range of 36-60 years and they were subjected to checks subtending a visual angle of 15, 30, and 120 minutes of arc. The stimulus configuration comprised of the transient pattern reversal method in which a black and white checker board is generated (full field on a VEP Monitor by an Evoked Potential Recorder (RMS EMG. EPMARK II. The statistical analysis was done by One Way Analysis of Variance (ANOVA using EPI INFO 6. Results: In Group I, the maximum (max. P100 latency of 98.8 ± 4.7 and the max. P100 amplitude of 10.05 ± 3.1 μV was obtained with checks of 90 minutes. In Group II, the max. P100 latency of 105.19 ± 4.75 msec as well as the max. P100 amplitude of 8.23 ± 3.30 μV was obtained with 15 minutes. The min. P100 latency in both the groups was obtained with checks of 120 minutes while the min. P100 amplitude was obtained with 180 minutes. A statistically significant difference was derived between means of P100 latency for 15 and 30 minutes with reference to its value for 120 minutes and between the mean value of P100 amplitude for 120 minutes and that of 90 and 180 minutes. Conclusion: Altering the size of stimulus (visual angle has an effect on the PRVEP parameters. Our study found that the 120

  9. Color impact in visual attention deployment considering emotional images

    Science.gov (United States)

    Chamaret, C.

    2012-03-01

    Color is a predominant factor in the human visual attention system. Even if it cannot be sufficient to the global or complete understanding of a scene, it may impact the visual attention deployment. We propose to study the color impact as well as the emotion aspect of pictures regarding the visual attention deployment. An eye-tracking campaign has been conducted involving twenty people watching half pictures of database in full color and the other half of database in grey color. The eye fixations of color and black and white images were highly correlated leading to the question of the integration of such cues in the design of visual attention model. Indeed, the prediction of two state-of-the-art computational models shows similar results for the two color categories. Similarly, the study of saccade amplitude and fixation duration versus time viewing did not bring any significant differences between the two mentioned categories. In addition, spatial coordinates of eye fixations reveal an interesting indicator for investigating the differences of visual attention deployment over time and fixation number. The second factor related to emotion categories shows evidences of emotional inter-categories differences between color and grey eye fixations for passive and positive emotion. The particular aspect associated to this category induces a specific behavior, rather based on high frequencies, where the color components influence the visual attention deployment.

  10. Analysis of brain-stem auditory evoked potential and visual evoked potential in patients with Parkinson disease

    Institute of Scientific and Technical Information of China (English)

    Qiaorong Deng; Jianzhong Deng; Yanmin Zhao; Xiaohai Yan; Pin Chen

    2006-01-01

    BACKGROUND: With the development of neuroelectrophysiology, it had been identified that all kinds of evoked potentials might reflect the functional status of corresponding pathway. Evoked potentials recruited in the re search of PD, it can be known whether other functional pathway of nervous system is impaired. OBJECTIVE: To observe whether brainstem auditory and visual passageway are impaired in patients with Parkinson disease (PD), and compare with non-PD patients concurrently. DESIGN: A non-randomized concurrent controlled observation. SETTINGS: Henan Provincial Tumor Hospital; Anyang District Hospital. PARTICIPANTS: Thirty-two cases of PD outpatients and inpatients, who registered in the Department of Neurology, Anyang District Hospital from October 1997 to February 2006, were enrolled as the PD group, including 20 males and 12 females, aged 50-72 years old. Inclusive criteria: In accordance with the diagnostic criteria of PD recommended by the dyskinesia and PD group of neurology branch of Chinese Medical Association. Patients with diseases that could cause Parkinson syndrome were excluded by CT scanning or MRI examination. Meanwhile, 30 cases with non-neurological disease were selected from the Department of Internal Medicine of our hospital as the control group, including 19 males and 11 females, aged 45-70 years old. Including criteria: Without history of neurological disease or psychiatric disease; showing normal image on CT. And PD, Parkinson syndrome and Parkinsonism-plus were excluded by professional neurologist. All the patients were informed and agreed with the examination and clinical observation. METHODS: The electrophysiological examination and clinical observation of the PD patients and controls were conducted. The Reporter type 4-channel evoked potential machine (Italy) was used to check brain-stem auditory evoked potential (BAEP) and visual evoked potential (VEP). Why to be examined was explained to test taker. BAEP recording electrode was plac

  11. Dissociable modulation of overt visual attention in valence and arousal revealed by topology of scan path.

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    Jianguang Ni

    Full Text Available Emotional stimuli have evolutionary significance for the survival of organisms; therefore, they are attention-grabbing and are processed preferentially. The neural underpinnings of two principle emotional dimensions in affective space, valence (degree of pleasantness and arousal (intensity of evoked emotion, have been shown to be dissociable in the olfactory, gustatory and memory systems. However, the separable roles of valence and arousal in scene perception are poorly understood. In this study, we asked how these two emotional dimensions modulate overt visual attention. Twenty-two healthy volunteers freely viewed images from the International Affective Picture System (IAPS that were graded for affective levels of valence and arousal (high, medium, and low. Subjects' heads were immobilized and eye movements were recorded by camera to track overt shifts of visual attention. Algebraic graph-based approaches were introduced to model scan paths as weighted undirected path graphs, generating global topology metrics that characterize the algebraic connectivity of scan paths. Our data suggest that human subjects show different scanning patterns to stimuli with different affective ratings. Valence salient stimuli (with neutral arousal elicited faster and larger shifts of attention, while arousal salient stimuli (with neutral valence elicited local scanning, dense attention allocation and deep processing. Furthermore, our model revealed that the modulatory effect of valence was linearly related to the valence level, whereas the relation between the modulatory effect and the level of arousal was nonlinear. Hence, visual attention seems to be modulated by mechanisms that are separate for valence and arousal.

  12. Brain activity underlying visual perception and attention as inferred from TMS-EEG: a review.

    Science.gov (United States)

    Taylor, Paul Christopher John; Thut, Gregor

    2012-04-01

    Probing brain functions by brain stimulation while simultaneously recording brain activity allows addressing major issues in cognitive neuroscience. We review recent studies where electroencephalography (EEG) has been combined with transcranial magnetic stimulation (TMS) in order to investigate possible neuronal substrates of visual perception and attention. TMS-EEG has been used to study both pre-stimulus brain activity patterns that affect upcoming perception, and also the stimulus-evoked and task-related inter-regional interactions within the extended visual-attentional network from which attention and perception emerge. Local processes in visual areas have been probed by directly stimulating occipital cortex while monitoring EEG activity and perception. Interactions within the attention network have been probed by concurrently stimulating frontal or parietal areas. The use of tasks manipulating implicit and explicit memory has revealed in addition a role for attentional processes in memory. Taken together, these studies helped to reveal that visual selection relies on spontaneous intrinsic activity in visual cortex prior to the incoming stimulus, their control by attention, and post-stimulus processes incorporating a re-entrant bias from frontal and parietal areas that depends on the task.

  13. Value-driven attentional and oculomotor capture during goal-directed, unconstrained viewing.

    Science.gov (United States)

    Anderson, Brian A; Yantis, Steven

    2012-11-01

    Covert shifts of attention precede and direct overt eye movements to stimuli that are task relevant or physically salient. A growing body of evidence suggests that the learned value of perceptual stimuli strongly influences their attentional priority. For example, previously rewarded but otherwise irrelevant and inconspicuous stimuli capture covert attention involuntarily. It is unknown, however, whether stimuli also draw eye movements involuntarily as a consequence of their reward history. Here, we show that previously rewarded but currently task-irrelevant stimuli capture both attention and the eyes. Value-driven oculomotor capture was observed during unconstrained viewing, when neither eye movements nor fixations were required, and was strongly related to individual differences in visual working memory capacity. The appearance of a reward-associated stimulus came to evoke pupil dilation over the course of training, which provides physiological evidence that the stimuli that elicit value-driven capture come to serve as reward-predictive cues. These findings reveal a close coupling of value-driven attentional capture and eye movements that has broad implications for theories of attention and reward learning.

  14. Transient Evoked and Distortion Product Otoacoustic Emissions in a Group of Neonates

    Science.gov (United States)

    Silva, Giovanna Cesar; Delecrode, Camila Ribas; Kemp, Adriana Tahara; Martins, Fabiana; Cardoso, Ana Claudia Vieira

    2015-01-01

    Introduction The most commonly used method in neonatal hearing screening programs is transient evoked otoacoustic emissions in the first stage of the process. There are few studies comparing transient evoked otoacoustic emissions with distortion product, but some authors have investigated the issue. Objective To correlate the results of transient evoked and distortion product otoacoustic emissions in a Brazilian maternity hospital. Methods This is a cross-sectional, comparative, and prospective study. The study included 579 newborns, ranging from 6 to 54 days of age, born in a low-risk maternity hospital and assessed for hearing loss. All neonates underwent hearing screening by transient evoked and distortion product otoacoustic emissions. The results were analyzed using the Spearman correlation test to relate the two procedures. Results The pass index on transient evoked otoacoustic emissions was 95% and on distortion product otoacoustic emissions was 91%. The comparison of the two procedures showed that 91% of neonates passed on both procedures, 4.5% passed only on transient evoked otoacoustic emissions, 0.5% passed only on distortion product otoacoustic emissions, and 4% failed on both procedures. The inferential analysis showed a significant strong positive relationship between the two procedures. Conclusion The failure rate was higher in distortion product otoacoustic emissions when compared with transient evoked; however, there was correlation between the results of the procedures. PMID:26157501

  15. Manipulating Bodily Presence Affects Cross-Modal Spatial Attention: A Virtual-Reality-Based ERP Study

    Science.gov (United States)

    Harjunen, Ville J.; Ahmed, Imtiaj; Jacucci, Giulio; Ravaja, Niklas; Spapé, Michiel M.

    2017-01-01

    Earlier studies have revealed cross-modal visuo-tactile interactions in endogenous spatial attention. The current research used event-related potentials (ERPs) and virtual reality (VR) to identify how the visual cues of the perceiver’s body affect visuo-tactile interaction in endogenous spatial attention and at what point in time the effect takes place. A bimodal oddball task with lateralized tactile and visual stimuli was presented in two VR conditions, one with and one without visible hands, and one VR-free control with hands in view. Participants were required to silently count one type of stimulus and ignore all other stimuli presented in irrelevant modality or location. The presence of hands was found to modulate early and late components of somatosensory and visual evoked potentials. For sensory-perceptual stages, the presence of virtual or real hands was found to amplify attention-related negativity on the somatosensory N140 and cross-modal interaction in somatosensory and visual P200. For postperceptual stages, an amplified N200 component was obtained in somatosensory and visual evoked potentials, indicating increased response inhibition in response to non-target stimuli. The effect of somatosensory, but not visual, N200 enhanced when the virtual hands were present. The findings suggest that bodily presence affects sustained cross-modal spatial attention between vision and touch and that this effect is specifically present in ERPs related to early- and late-sensory processing, as well as response inhibition, but do not affect later attention and memory-related P3 activity. Finally, the experiments provide commeasurable scenarios for the estimation of the signal and noise ratio to quantify effects related to the use of a head mounted display (HMD). However, despite valid a-priori reasons for fearing signal interference due to a HMD, we observed no significant drop in the robustness of our ERP measurements. PMID:28275346

  16. Effects of symptomatic treatments on cutaneous hyperalgesia and laser evoked potentials during migraine attack.

    Science.gov (United States)

    de Tommaso, M; Losito, L; Libro, G; Guido, M; Di Fruscolo, O; Sardaro, M; Sciruicchio, V; Lamberti, P; Livrea, P

    2005-05-01

    Previously an amplitude enhancement of laser evoked potentials (LEPs) was detected during migraine attack: we further examined pain threshold to CO2 laser stimuli and LEPs during attacks, evaluating the effect of almotriptan, lysine-acetylsalicylate and placebo treatment on cutaneous hyperalgesia to thermal stimuli delivered by CO2 laser and on LEP components. Eighteen patients suffering from migraine without aura were analysed. They were divided into three groups of six patients each, randomly assigned to lysine acetyl-salicylate, almotriptan or placebo treatments. The supraorbital zones and the dorsum of the hand were stimulated on both the symptomatic and not symptomatic side in all patients. The LEPs were recorded by 25 scalp electrodes. During attacks, the P2 wave was significantly enhanced; the amplitude of the P2 component obtained by the stimulation of the supraorbital zone during the attack on the side of the headache was significantly correlated with the intensity of pain and the frequency of headache. Both almotriptan and lysine acetyl-salicylate significantly reduced the P2 amplitude but they showed no effects on hyperalgesia to laser stimulation; headache relief following therapy was correlated with the reduction of the P2 amplitude. The cortical elaboration of laser-induced experimental pain seemed increased during migraine attack, and the severity of headache was mainly related to the increase of the later LEPs components expressing the attentive and emotive compounds of suffering. Reversion of this process appeared to be primarily responsible for the efficacy of drugs in treating migraine, though both almotriptan and lysine-acetil salicilate seemed to have no effect in reducing sensitization at second and third order nociceptive neurons.

  17. Different states of synaptotagmin regulate evoked versus spontaneous release

    Science.gov (United States)

    Bai, Hua; Xue, Renhao; Bao, Huan; Zhang, Leili; Yethiraj, Arun; Cui, Qiang; Chapman, Edwin R.

    2016-03-01

    The tandem C2-domains of synaptotagmin 1 (syt) function as Ca2+-binding modules that trigger exocytosis; in the absence of Ca2+, syt inhibits spontaneous release. Here, we used proline linkers to constrain and alter the relative orientation of these C2-domains. Short poly-proline helices have a period of three, so large changes in the relative disposition of the C2-domains result from changing the length of the poly-proline linker by a single residue. The length of the linker was varied one residue at a time, revealing a periodicity of three for the ability of the linker mutants to interact with anionic phospholipids and drive evoked synaptic transmission; syt efficiently drove exocytosis when its tandem C2-domains pointed in the same direction. Analysis of spontaneous release revealed a reciprocal relationship between the activation and clamping activities of the linker mutants. Hence, different structural states of syt underlie the control of distinct forms of synaptic transmission.

  18. Contrast Sensitivity versus Visual Evoked Potentials in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Javad Heravian Shandiz

    2010-01-01

    Full Text Available Purpose: To compare the Cambridge contrast sensitivity (CS test and visual evoked potentials (VEP in detecting visual impairment in a population of visually symptomatic and asymptomatic patients affected by clinically definite multiple sclerosis (MS. Methods: Fifty patients (100 eyes presenting with MS and 25 healthy subjects (50 eyes with normal corrected visual acuity were included in this study. CS was determined using the Cambridge Low Contrast Grating test and VEP was obtained in all eyes. Findings were evaluated in two age strata of 10-29 and 30-49 years. Results: Of the 42 eyes in the 10-29 year age group, CS was abnormal in 22 (52%, VEP was also abnormal in 22 (52%, but only 12 eyes (28% had visual symptoms. Of the 58 eyes in the 30-49 year group, CS was abnormal in 7 (12%, VEP was abnormal in 34 (58%, while only 11 eyes were symptomatic. No single test could detect all of the abnormal eyes. Conclusion: The Cambridge Low Contrast Grating test is useful for detection of clinical and subclinical visual dysfunction especially in young patients with multiple sclerosis. Nevertheless, only a combination of CS and VEP tests can detect most cases of visual dysfunction associated with MS.

  19. Grating-evoked cortical potentials and perceived contrast (A)

    Science.gov (United States)

    Strasburger, Hans; Scheidler, Wolfgang; Rentschler, Ingo

    Unlike subjective perception of contrast, steady-state evoked cortical potentials (VEP's) elicited with counterphased gratings may vary abruptly with changes in spatial frequency.(1) To avoid possible artifacts we developed a digital fast-sweep technique for investigating this discrepancy. In most of our 13 subjects, at high stimulus contrasts the dependency of VEP amplitude on spatial frequency had two pronounced peaks separated by a sharp notch at around 3 cycles per degree. With decreasing contrast these variations leveled out, and a unimodal response function was obtained at low contrast. A linear relationship between log contrast and VEP amplitude(2) was found for any given spatial frequency only in the low-contrast range. With increasing contrast the VEP amplitude saturated at a rate that depended clearly on spatial frequency, with a nonmonotonous dependency occurring at intermediate spatial frequencies. The latter phenomenon of oversaturation apparently gave rise to the above-mentioned bimodal response characteristic. Results of a careful analysis of VEP phase lags are added. (1) C. W. Tyler et al., Brain Res. 33, 535 (1978). (2) F. W. Campbell and L. Maffei, J. Physiol. 207, 635 (1970).

  20. Changes of Transient Visual Evoked Potentials in Dyslexic Children

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    Ka Yan Leung

    2011-05-01

    Full Text Available Objectives: To investigate the characteristics of Visual Evoked Potentials (VEP in dyslexics. Methods: Fourteen children, 7 dyslexics and 7 control, aged 7 to 8 years were recruited. All dyslexic subjects were diagnosed by clinical psychologist. All subjects are from mainstream primary schools in Hong Kong, using Chinese and Cantonese as their primary written and spoken language, having normal visual acuity and IQ. Children with reported emotional or behavioral problems or binocular vision problem were excluded. All the subjects participated in pattern-reversal VEP measurements binocularly with 1000msec recording time. Four conditions of stimulations (checkersize: 180 min of arc were applied. (15-Hz at 15% contrast (25-Hz at 1% contrast (315-Hz at 15% contrast (415-Hz at 1% contrast Results: At 15% contrast stimulus, dyslexic subjects showed smaller amplitudes in both frequencies compared with the control group, especially in higher frequency. At 1% contrast stimulus, dyslexic subjects also showed smaller amplitudes in both frequencies and obvious reduction was observed at the later part of the recording period. No observable difference was showed in the latency of both contrast conditions. Conclusion: The attenuated VEP responses in higher frequency at low contrast condition in dyslexic group showed the changes of the transient visual response and this implies an abnormality in magnocellular pathway in dyslexia.

  1. Investigating the mechanisms of visually-evoked tactile sensations.

    Science.gov (United States)

    McKenzie, Kirsten J; Lloyd, Donna M; Brown, Richard J; Plummer, Faye; Poliakoff, Ellen

    2012-01-01

    When attempting to detect a near-threshold signal, participants often incorrectly report the presence of a signal, particularly when a stimulus in a different modality is presented. Here we investigated the effect of prior experience of bimodal visuotactile stimuli on the rate of falsely reported touches in the presence of a light. In Experiment 1, participants made more false alarms in light-present than light-absent trials, despite having no experience of the experimental visuotactile pairing. This suggests that light-evoked false alarms are a consequence of an existing association, rather than one learned during the experiment. In Experiment 2, we sought to manipulate the strength of the association through prior training, using supra-threshold tactile stimuli that were given a high or low association with the light. Both groups still exhibited an increased number of false alarms during light-present trials, however, the low association group made significantly fewer false alarms across conditions, and there was no corresponding group difference in the number of tactile stimuli correctly identified. Thus, while training did not affect the boosting of the tactile signal by the visual stimulus, the low association training affected perceptual decision-making more generally, leading to a lower number of illusory touch reports, independent of the light.

  2. Effects of spatial frequency on visual evoked magnetic fields.

    Science.gov (United States)

    Tsuruhara, Aki; Nagata, Yuko; Suzuki, Masaya; Inui, Koji; Kakigi, Ryusuke

    2013-05-01

    Psychophysical and visual evoked potential (VEP) studies have shown that spatial frequency of a visual stimulus affects contrast sensitivity and VEPs in humans. However, it is not clear whether and how the effect of spatial frequency varies among cortical areas. Considering that all visual inputs to the retina could be expressed as a sum of sinusoidal gratings of different spatial frequencies, the effect of spatial frequency must be clarified to separate the brain activity specific to each visual stimulus. In order to examine the effect of spatial frequency on different cortical areas, the present study compared cortical responses to sinusoidal gratings of seven different spatial frequencies using magnetoencephalography (MEG). MEG waveforms of twelve healthy adults in response to sinusoidal gratings of 0.3-18.1 cycles per degree were subjected to a multi-dipole analysis. As a result, the effect of spatial frequency was significant on the first peak latency and amplitude of the source activity around V1 and V2 but not on the source activity around V3 and V6, indicating that the effect of spatial frequency varies across different visual areas in the human brain. Our results also suggest that the responses in V1 and V2 that have a peak around 90 ms and that of V6 peaking around 120 ms should be separated to investigate the stimulus-specific cortical response, particularly when examining effects of spatial frequency on the response latency.

  3. Visual Evoked Potentials in Patients with Classic Migraine

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    Akbar Hamzei-Moghaddam

    2013-04-01

    Full Text Available Background: Migraine is considered as a chronic disease. Ocular symptoms and sensitivity to light stimuli are common in the patients with such disease. There are some evident that visual system function in the patients with migraine is impaired even between the attacks as compared with health people. In this study, we examine Visual Evoked Potential in 30 patients suffered from migraine before, during and after aura. Materials and Methods: 30 patients suffered from classic migraine and with visual aura were evaluated in terms of visual stimulatory potentials before, during and after aura. P-100 latency and amplitude were evaluation criteria in our study. The results of this investigation were evaluated by χ2 test.Results: Abnormal amplitude frequency was occurred in 17 cases before aura, in 27 cases during aura and in 20 cases, it occurred after aura. Reduction of the amplitude wave p-100 during and after aura was significantly more in both eyes (p<0.05. Ten cases had abnormal P-100 latency during aura and the other two cases had it after aura. There is a significant difference in the P-100 latency during aura (p<0.05. There is no difference between the changes in visual stimulatory potentials with gender.Conclusion: Some changes were found in the parameters in the visual stimulatory potentials in the patients with classic migraine before, during and after aura.

  4. Evoking Baldwin’s Blues: The Experience of Dislocated Listening

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    Rashida K. Braggs

    2015-09-01

    Full Text Available “It is only in his music [. . .] that the Negro in America has been able to tell his story. It is a story which otherwise has yet to be told and which no American is prepared to hear,” so wrote James Baldwin in “Many Thousands Gone.” Throughout his career, James Baldwin returned to this incomprehension of African-American experience. He continually privileged music in his literature, crafting his own literary blues to address it. Baldwin’s blues resonated even more powerfully and painfully for its emotional and geographical dislocation. In this article, Rashida K. Braggs argues that it was the combination of music, word, and migration that prompted Baldwin’s own deeper understanding. Exploring her term dislocated listening, Braggs investigates how listening to music while willfully dislocated from one’s cultural home prompts a deeper understanding of African-American experience. The distance disconcerts, leaving one more vulnerable, while music impels the reader, audience, and even Baldwin to identify with some harsh realities of African-American experience. Baldwin evokes the experience of dislocated listening in his life and in “Sonny’s Blues.” Braggs also creates an experience of dislocated listening through her video performance of Baldwin’s words, thus attempting to draw the reader as well into a more attuned understanding of African-American experience.

  5. Vestibular evoked myogenic potential in sudden sensorineural hearing loss

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    Feroze Kancharu Khan

    2013-01-01

    Full Text Available Aim and Objective: To investigate saccular damage in patients with sudden sensorineural hearing loss (SSNHL with or without vertigo and to evaluate the saccular damage according to the hearing loss and presence or absence of vertigo. Materials and Methods: All tests done in this study were performed in the audio vestibular unit of ENT department from September 2009 to November 2010. Statistical Analysis Used: The association between the severity of hearing loss and changes in the vestibular evoked myogenic potential (VEMP recordings were assessed using descriptive statistics. The pattern of VEMP in different diseases and also the behavior of VEMP in presence or absence of vertigo were evaluated using SPSS 15. Results: Among 27 patients there were 11 cases of idiopathic SSNHL. Out of nine unaffected ears, 88% had normal and 12% had absent VEMP. Whereas out of 13 affected ears, only 53.9% had normal VEMP. Among all the 54 ears, 17 ears had normal hearing. In this group 76.47% had normal VEMP. The group with hearing loss > 90 dB had 61.53% absent VEMP. Conclusions: In patients with unilateral SSNHL, there was a tendency for the affected ear to have absent VEMP indicating the saccular involvement. The extent of saccular damage did not correspond to the amount of hearing loss or presence or absence of vertigo.

  6. A Subspace Method for Dynamical Estimation of Evoked Potentials

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    Stefanos D. Georgiadis

    2007-01-01

    Full Text Available It is a challenge in evoked potential (EP analysis to incorporate prior physiological knowledge for estimation. In this paper, we address the problem of single-channel trial-to-trial EP characteristics estimation. Prior information about phase-locked properties of the EPs is assesed by means of estimated signal subspace and eigenvalue decomposition. Then for those situations that dynamic fluctuations from stimulus-to-stimulus could be expected, prior information can be exploited by means of state-space modeling and recursive Bayesian mean square estimation methods (Kalman filtering and smoothing. We demonstrate that a few dominant eigenvectors of the data correlation matrix are able to model trend-like changes of some component of the EPs, and that Kalman smoother algorithm is to be preferred in terms of better tracking capabilities and mean square error reduction. We also demonstrate the effect of strong artifacts, particularly eye blinks, on the quality of the signal subspace and EP estimates by means of independent component analysis applied as a prepossessing step on the multichannel measurements.

  7. Electrophysiological correlates of face-evoked person knowledge.

    Science.gov (United States)

    Taylor, JohnMark; Shehzad, Zarrar; McCarthy, Gregory

    2016-07-01

    Face recognition includes identifying a face as perceptually familiar and recollecting biographical information, or person-knowledge, associated with the face. The majority of studies examining the neural basis of face recognition have confounded these stages by comparing brain responses evoked by novel and perceptually familiar famous faces. Here, we recorded EEG in two tasks in which subjects viewed two sets of faces that were equally perceptually familiar, but which had differing levels of associated person-knowledge. Our results dissociated the effects of person-knowledge from perceptual familiarity. Faces with associated biographical information elicited a larger ∼600ms centroparietal positivity in both a passive viewing task in which subjects viewed faces without explicitly responding, and an active question-answering task in which subjects indicated whether or not they knew particular facts about the faces. In the question task only, person-knowledge was associated with a negative ERP difference over right posterior scalp over the 170-450ms interval which appeared again at long latency (>900ms).

  8. Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen

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    Celso Soiti Matsumoto

    2014-01-01

    Full Text Available Purpose. To determine whether organic electroluminescence (OLED screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs. Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years. Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

  9. Pattern reversal visual evoked potentials in migraine subjects without aura

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    Pedro F. Moreira Filho

    1994-12-01

    Full Text Available Twenty seven patients with migraine without aura were investigated. The age was between 12 and 54 years; 5 were men and 22 women. The diagnosis of migraine was made according to the classification proposed by the International Headache Society. The method of visual evoked potential was performed with pattern reversal (VEP-PR, with monocular stimulation. The stimulation was performed with pattern reversal with 4x4 cm black and white and red and green squared screen placed 1 meter from the nasion at stimulus frequency 1/s; 128 individual trials were analysed. The VEP-PR with black/white and red/green study showed a significant increase of value of the P-100 latency in 10 migraine patients. In 8 cases the LP100 in VEP-PR black/white was normal but in VEP-PR red/green the LP100 showed increase. Specifically in 1 of our cases, LP100 were normal in VEP-PR black/white but in the red/green there were no reproductice waves. On basis of these observations we consider that the method of VEP-PR is an useful instrument for investigation of migraine patients without aura.

  10. Development of Brainstem-Evoked Responses in Congenital Auditory Deprivation

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    J. Tillein

    2012-01-01

    Full Text Available To compare the development of the auditory system in hearing and completely acoustically deprived animals, naive congenitally deaf white cats (CDCs and hearing controls (HCs were investigated at different developmental stages from birth till adulthood. The CDCs had no hearing experience before the acute experiment. In both groups of animals, responses to cochlear implant stimulation were acutely assessed. Electrically evoked auditory brainstem responses (E-ABRs were recorded with monopolar stimulation at different current levels. CDCs demonstrated extensive development of E-ABRs, from first signs of responses at postnatal (p.n. day 3 through appearance of all waves of brainstem response at day 8 p.n. to mature responses around day 90 p.n.. Wave I of E-ABRs could not be distinguished from the artifact in majority of CDCs, whereas in HCs, it was clearly separated from the stimulus artifact. Waves II, III, and IV demonstrated higher thresholds in CDCs, whereas this difference was not found for wave V. Amplitudes of wave III were significantly higher in HCs, whereas wave V amplitudes were significantly higher in CDCs. No differences in latencies were observed between the animal groups. These data demonstrate significant postnatal subcortical development in absence of hearing, and also divergent effects of deafness on early waves II–IV and wave V of the E-ABR.

  11. Decoding covert shifts of attention induced by ambiguous visuospatial cues

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    Romain eTrachel

    2015-06-01

    Full Text Available Simple and unambiguous visual cues (e.g. an arrow can be used to trigger covert shifts of visual attention away from the center of gaze. The processing of visual stimuli is enhanced at the attended location. Covert shifts of attention modulate the power of cerebral oscillations in the alpha band over parietal and occipital regions. These modulations are sufficiently robust to be decoded on a single trial basis from electro-encephalography (EEG signals. It is often assumed that covert attention shifts are under voluntary control, and also occur in more natural and complex environments, but there is no direct evidence to support this assumption. We address this important issue by using random-dot stimuli to cue one of two opposite locations, where a visual target is presented. We contrast two conditions in which the random-dot motion is either predictive of the target location or contains ambiguous information. Behavioral results show attention shifts in anticipation of the visual target, in both conditions. In addition, these attention shifts involve similar neural sources, and the EEG can be decoded on a single trial basis. These results shed a new light on the behavioral and neural correlates of visuospatial attention, with implications for Brain-Computer Interfaces (BCI based on covert attention shifts.

  12. Effects of continuous conditioning noise and light on the auditory- and visual-evoked potentials of the guinea pig.

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    Goksoy, Cuneyt; Demirtas, Serdar; Ates, Kahraman

    2005-11-01

    Neurophysiological studies aiming to explore how the brain integrates information from different brain regions are increasing in the literature. The aim of the present study is to explore intramodal (binaural, binocular) and intermodal (audio-visual) interactions in the guinea pig brain through the observation of changes in evoked potentials by generalized continuous background activity. Seven chronically prepared animals were used in the study and the recordings were made as they were awake. Epidural electrodes were implanted to the skulls by using stereotaxic methods. Continuous light for retinal or continuous white noise for cochlear receptors were used as continuous conditioning stimuli for generalized stimulation. To evoke auditory or visual potentials, click or flash were used as transient imperative stimuli. The study data suggest that (a) white noise applied to one ear modifies the response to click in the contralateral ear which is a binaural interaction; (b) continuous light applied to one eye modifies the response to flash applied to the contralateral eye which is interpreted as a binocular interaction; (c) regardless of the application side, white noise similarly modified the response to flash applied to the either eye connoting a nonspecific effect of white noise on vision, independent from spatial hearing mechanisms; (d) on the other hand, continuous light, in either eye, did not affect the response to click applied to any ear, reminding a 'one-way' interaction that continuous aural stimulation affects visual response.

  13. Quantification of mid and late evoked sinks in laminar current source density profiles of columns in the primary auditory cortex.

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    Schaefer, Markus K; Hechavarría, Julio C; Kössl, Manfred

    2015-01-01

    Current source density (CSD) analysis assesses spatiotemporal synaptic activations at somatic and/or dendritic levels in the form of depolarizing current sinks. Whereas many studies have focused on the short (primary auditory cortex of Mongolian gerbils. By applying an algorithm for contour calculation, three distinct mid and four late evoked sinks were identified in layers I, III, Va, VIa, and VIb. Our results further showed that the patterns of intracortical information-flow remained qualitatively similar for low and for high sound pressure level stimuli at the characteristic frequency (CF) as well as for stimuli ± 1 octave from CF. There were, however, differences associated with the strength, vertical extent, onset latency, and duration of the sinks for the four stimulation paradigms used. Stimuli one octave above the most sensitive frequency evoked a new, and quite reliable, sink in layer Va whereas low level stimulation led to the disappearance of the layer VIb sink. These data indicate the presence of input sources specifically activated in response to level and/or frequency parameters. Furthermore, spectral integration above vs. below the CF of neurons is asymmetric as illustrated by CSD profiles. These results are important because synaptic feedback associated with mid and late sinks-beginning at 50 ms post stimulus latency-is likely crucial for response modulation resulting from higher order processes like memory, learning or cognitive control.

  14. Unitary attention in callosal agenesis.

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    Dell'acqua, R; Jolicoeur, P; Lassonde, M; Angrilli, A; De Bastiani, P; Pascali, A

    2005-01-01

    The interhemispheric organisation of two specific components of attention was investigated in three patients affected by partial or complete agenesis of the corpus callosum. A visuospatial component of attention was explored using a visual search paradigm in which target and distractors were displayed either unilaterally within a single visual hemifield, or bilaterally across both visual hemifields in light of prior work indicating that split-brain patients were twice as fast to scan bilateral displays compared to unilateral displays. A central component of attention was explored using a psychological refractory period (PRP) paradigm in which two visual stimuli were presented laterally at various stimulus onset asynchronies (SOAs), with each stimulus associated with a different speeded two-alternative choice task. The stimulus-response compatibility in the second task was systematically manipulated in this paradigm, in light of prior work indicating that split-brain patients exhibited a close-to-normal PRP effect (i.e., slowing of the second response as SOA is decreased), with, however, abnormally decreasing effects of the manipulation of the response mapping on the second task speed as SOA was decreased. The present results showed that, although generally slower than normals in carrying out the two tasks, the performance of each of the three acallosal patients was formally equivalent to the performance of a matched control group of normal individuals. In the visual search task, the search rate of the acallosal patients was the same for unilateral and bilateral displays. Furthermore, in the PRP task, there was more mutual interference between the lateralised tasks for the acallosal patients than that evidenced in the performance of the matched control group. It is concluded that the visuospatial component and the central component of attention in agenesis of the corpus callosum are interhemispherically integrated systems.

  15. Mindful movement and skilled attention

    OpenAIRE

    2015-01-01

    Bodily movement has long been employed as a foundation for cultivating mental skills such as attention, self-control or mindfulness, with recent studies documenting the positive impacts of mindful movement training, such as yoga and tai chi. A parallel “mind-body connection” has also been observed in many developmental disorders. We elaborate a spectrum of mindfulness by considering ADHD, in which deficient motor control correlates with impaired (disinhibited) behavioral control contributing ...

  16. The vestibular implant: Frequency-dependency of the electrically evoked Vestibulo-Ocular Reflex in humans

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    Raymond eVan De Berg

    2015-01-01

    Full Text Available The Vestibulo-Ocular Reflex (VOR shows frequency-dependent behavior. This study investigated whether the characteristics of the electrically evoked VOR (eVOR elicited by a vestibular implant, showed the same frequency-dependency.Twelve vestibular electrodes implanted in 7 patients with bilateral vestibular hypofunction were tested. Stimuli consisted of amplitude-modulated electrical stimulation with a sinusoidal profile at frequencies of 0.5Hz, 1Hz, and 2Hz. The main characteristics of the eVOR were evaluated and compared to the natural VOR characteristics measured in a group of age-matched healthy volunteers who were subjected to horizontal whole body rotations with equivalent sinusoidal velocity profiles at the same frequencies.A strong and significant effect of frequency was observed in the total peak eye velocity of the eVOR. This effect was similar to that observed in the natural VOR. Other characteristics of the (eVOR (angle, habituation-index, and asymmetry showed no significant frequency-dependent effect. In conclusion, this study demonstrates that, at least at the specific (limited frequency range tested, responses elicited by a vestibular implant closely mimic the frequency-dependency of the normal vestibular system.

  17. The vestibular implant: frequency-dependency of the electrically evoked vestibulo-ocular reflex in humans.

    Science.gov (United States)

    van de Berg, Raymond; Guinand, Nils; Nguyen, T A Khoa; Ranieri, Maurizio; Cavuscens, Samuel; Guyot, Jean-Philippe; Stokroos, Robert; Kingma, Herman; Perez-Fornos, Angelica

    2014-01-01

    The vestibulo-ocular reflex (VOR) shows frequency-dependent behavior. This study investigated whether the characteristics of the electrically evoked VOR (eVOR) elicited by a vestibular implant, showed the same frequency-dependency. Twelve vestibular electrodes implanted in seven patients with bilateral vestibular hypofunction (BVH) were tested. Stimuli consisted of amplitude-modulated electrical stimulation with a sinusoidal profile at frequencies of 0.5, 1, and 2 Hz. The main characteristics of the eVOR were evaluated and compared to the "natural" VOR characteristics measured in a group of age-matched healthy volunteers who were subjected to horizontal whole body rotations with equivalent sinusoidal velocity profiles at the same frequencies. A strong and significant effect of frequency was observed in the total peak eye velocity of the eVOR. This effect was similar to that observed in the "natural" VOR. Other characteristics of the (e)VOR (angle, habituation-index, and asymmetry) showed no significant frequency-dependent effect. In conclusion, this study demonstrates that, at least at the specific (limited) frequency range tested, responses elicited by a vestibular implant closely mimic the frequency-dependency of the "normal" vestibular system.

  18. Quantifying interhemispheric symmetry of somatosensory evoked potentials with the intraclass correlation coefficient.

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    van de Wassenberg, Wilma J G; van der Hoeven, Johannes H; Leenders, Klaus L; Maurits, Natasha M

    2008-06-01

    Although large intersubject variability is reported for cortical somatosensory evoked potentials (SEPs), variability between hemispheres within one subject is thought to be small. Therefore, interhemispheric comparison of SEP waveforms might be clinically useful to detect unilateral abnormalities in cortical sensory processing. We developed and evaluated a new technique to quantify interhemispheric SEP symmetry that uses a time interval including multiple SEP components, measures similarity of SEP waveforms between both hemispheres and results in high symmetry values even in the presence of small interhemispheric anatomic differences. Median nerve SEPs were recorded in 50 healthy subjects (20-70 years) using 128-channel EEG. Symmetry was quantified by the intraclass correlation coefficient and correlation coefficient between global field power of left and right median nerve SEPs. In 74% of subjects left-right intraclass correlation coefficient was higher than 0.60, implying high SEP hemispheric symmetry in terms of shape and amplitude. Left-right intraclass correlation coefficients lower than 0.60 were due to differences in amplitude, unilateral absence of peaks, or shape differences. We quantified SEP waveform interhemispheric symmetry and found it to be high in most healthy subjects. This technique may therefore be useful for detection of unilateral abnormalities in cortical sensory processing.

  19. [Neonatal screening of deafness: evoked otoacoustic emissions or acoustic distortion products?].

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    Roman, S; Mondain, M; Triglia, J M; Uziel, A

    2001-01-01

    Transiently evoked otoacoustic emissions (TEOAE) allows an auditory screening in neonates above 30 dB and between 2 kHz to 4 kHz. Another type of otoacoustic emissions, the distortion product (DP) allows a similar screening and provides more specific frequency information over a broader frequency range, including frequencies below 2 kHz and above 4 kHz. The goal of this study was to determine 1) the interest of distortion product in comparison with TEOAE in a auditory screening program in neonates; 2) The predictive value of information extracted from otoacoustic emissions recordings, on frequential parameters of distortion product (DP). In this prospective study, TEOAE and DP were successively recorded in 20 neonates (34 ears) with risk of hearing impairment, using the ILO92 software and hardware. When TEOAs were no detectable (9/34), the DPs were no detectable neither (10/34). When TEOAs were detectable, the Dps carried more specific frequency information above 1 kHz in 52 to 80% of the patients. DP amplitudes have been quantitatively correlated with TEOA energy bands. Correlations between DP and TEOA have been objectivized for DP2.5 and DP4 with OE2, and for DP4 and DP6 with OE5. The correlation predictive value was above 85%. In conclusion, this study demonstrated that analysis of TEOA spectrums procures frequential information without requiring DP recordings.

  20. Auditory evoked fields to vocalization during passive listening and active generation in adults who stutter.

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    Beal, Deryk S; Cheyne, Douglas O; Gracco, Vincent L; Quraan, Maher A; Taylor, Margot J; De Nil, Luc F

    2010-10-01

    We used magnetoencephalography to investigate auditory evoked responses to speech vocalizations and non-speech tones in adults who do and do not stutter. Neuromagnetic field patterns were recorded as participants listened to a 1 kHz tone, playback of their own productions of the vowel /i/ and vowel-initial words, and actively generated the vowel /i/ and vowel-initial words. Activation of the auditory cortex at approximately 50 and 100 ms was observed during all tasks. A reduction in the peak amplitudes of the M50 and M100 components was observed during the active generation versus passive listening tasks dependent on the stimuli. Adults who stutter did not differ in the amount of speech-induced auditory suppression relative to fluent speakers. Adults who stutter had shorter M100 latencies for the actively generated speaking tasks in the right hemisphere relative to the left hemisphere but the fluent speakers showed similar latencies across hemispheres. During passive listening tasks, adults who stutter had longer M50 and M100 latencies than fluent speakers. The results suggest that there are timing, rather than amplitude, differences in auditory processing during speech in adults who stutter and are discussed in relation to hypotheses of auditory-motor integration breakdown in stuttering.