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Sample records for auditory forebrain frequency

  1. EFFECTS OF RESTRICTED BASILAR PAPILLAR LESIONS AND HAIR CELL REGENERATION ON AUDITORY FOREBRAIN FREQUENCY ORGANIZATION IN ADULT EUROPEAN STARLINGS

    Science.gov (United States)

    Irvine, Dexter R. F.; Brown, Mel; Kamke, Marc R.; Rubel, Edwin W

    2009-01-01

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 days or 6–10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies above 2 kHz in starlings tested 2 days after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which CFs normally increase from 2 to 6 kHz had characteristic frequency (CF) in the range 2–4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of pre-lesion responses and did not reflect central nervous system plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function. PMID:19474314

  2. Effects of restricted basilar papillar lesions and hair cell regeneration on auditory forebrain frequency organization in adult European starlings.

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    Irvine, Dexter R F; Brown, Mel; Kamke, Marc R; Rubel, Edwin W

    2009-05-27

    The frequency organization of neurons in the forebrain Field L complex (FLC) of adult starlings was investigated to determine the effects of hair cell (HC) destruction in the basal portion of the basilar papilla (BP) and of subsequent HC regeneration. Conventional microelectrode mapping techniques were used in normal starlings and in lesioned starlings either 2 d or 6-10 weeks after aminoglycoside treatment. Histological examination of the BP and recordings of auditory brainstem evoked responses confirmed massive loss of HCs in the basal portion of the BP and hearing losses at frequencies >2 kHz in starlings tested 2 d after aminoglycoside treatment. In these birds, all neurons in the region of the FLC in which characteristic frequencies (CFs) normally increase from 2 to 6 kHz had CF in the range of 2-4 kHz. The significantly elevated thresholds of responses in this region of altered tonotopic organization indicated that they were the residue of prelesion responses and did not reflect CNS plasticity. In the long-term recovery birds, there was histological evidence of substantial HC regeneration. The tonotopic organization of the high-frequency region of the FLC did not differ from that in normal starlings, but the mean threshold at CF in this frequency range was intermediate between the values in the normal and lesioned short-recovery groups. The recovery of normal tonotopicity indicates considerable stability of the topography of neuronal connections in the avian auditory system, but the residual loss of sensitivity suggests deficiencies in high-frequency HC function.

  3. Estradiol selectively enhances auditory function in avian forebrain neurons.

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    Caras, Melissa L; O'Brien, Matthew; Brenowitz, Eliot A; Rubel, Edwin W

    2012-12-01

    Sex steroids modulate vertebrate sensory processing, but the impact of circulating hormone levels on forebrain function remains unclear. We tested the hypothesis that circulating sex steroids modulate single-unit responses in the avian telencephalic auditory nucleus, field L. We mimicked breeding or nonbreeding conditions by manipulating plasma 17β-estradiol levels in wild-caught female Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii). Extracellular responses of single neurons to tones and conspecific songs presented over a range of intensities revealed that estradiol selectively enhanced auditory function in cells that exhibited monotonic rate level functions to pure tones. In these cells, estradiol treatment increased spontaneous and maximum evoked firing rates, increased pure tone response strengths and sensitivity, and expanded the range of intensities over which conspecific song stimuli elicited significant responses. Estradiol did not significantly alter the sensitivity or dynamic ranges of cells that exhibited non-monotonic rate level functions. Notably, there was a robust correlation between plasma estradiol concentrations in individual birds and physiological response properties in monotonic, but not non-monotonic neurons. These findings demonstrate that functionally distinct classes of anatomically overlapping forebrain neurons are differentially regulated by sex steroid hormones in a dose-dependent manner.

  4. Basal forebrain cholinergic input is not essential for lesion-induced plasticity in mature auditory cortex.

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    Kamke, Marc R; Brown, Mel; Irvine, Dexter R F

    2005-11-23

    The putative role of the basal forebrain cholinergic system in mediating lesion-induced plasticity in topographic cortical representations was investigated. Cholinergic immunolesions were combined with unilateral restricted cochlear lesions in adult cats, demonstrating the consequence of cholinergic depletion on lesion-induced plasticity in primary auditory cortex (AI). Immunolesions almost eliminated the cholinergic input to AI, while cochlear lesions produced broad high-frequency hearing losses. The results demonstrate that the near elimination of cholinergic input does not disrupt reorganization of the tonotopic representation of the lesioned (contralateral) cochlea in AI and does not affect the normal representation of the unlesioned (ipsilateral) cochlea. It is concluded that cholinergic basal forebrain input to AI is not essential for the occurrence of lesion-induced plasticity in AI.

  5. Toward a neurobiology of auditory object perception: What can we learn from the songbird forebrain?

    Institute of Scientific and Technical Information of China (English)

    Kai LU; David S. VICARIO

    2011-01-01

    In the acoustic world,no sounds occur entirely in isolation; they always reach the ears in combination with other sounds.How any given sound is discriminated and perceived as an independent auditory object is a challenging question in neuroscience.Although our knowledge of neural processing in the auditory pathway has expanded over the years,no good theory exists to explain how perception of auditory objects is achieved.A growing body of evidence suggests that the selectivity of neurons in the auditory forebrain is under dynamic modulation,and this plasticity may contribute to auditory object perception.We propose that stimulus-specific adaptation in the auditory forebrain of the songbird (and perhaps in other systems) may play an important role in modulating sensitivity in a way that aids discrimination,and thus can potentially contribute to auditory object perception [Current Zoology 57 (6):671-683,2011].

  6. A songbird forebrain area potentially involved in auditory discrimination and memory formation

    Indian Academy of Sciences (India)

    Raphael Pinaud; Thomas A Terleph

    2008-03-01

    Songbirds rely on auditory processing of natural communication signals for a number of social behaviors, including mate selection, individual recognition and the rare behavior of vocal learning – the ability to learn vocalizations through imitation of an adult model, rather than by instinct. Like mammals, songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals. Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (subfields L1, L2 and L3), the caudomedial and caudolateral mesopallium (CMM and CLM, respectively) and the caudomedial nidopallium (NCM). This review focuses on NCM, an auditory area previously proposed to be analogous to parts of the primary auditory cortex in mammals. Stimulation of songbirds with auditory stimuli drives vigorous electrophysiological responses and the expression of several activity-regulated genes in NCM. Interestingly, NCM neurons are tuned to species-specific songs and undergo some forms of experience-dependent plasticity in-vivo. These activity-dependent changes may underlie long-term modifications in the functional performance of NCM and constitute a potential neural substrate for auditory discrimination. We end this review by discussing evidence that suggests that NCM may be a site of auditory memory formation and/or storage.

  7. Origin and immunolesioning of cholinergic basal forebrain innervation of cat primary auditory cortex.

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    Kamke, Marc R; Brown, Mel; Irvine, Dexter R F

    2005-08-01

    Numerous studies have implicated the cholinergic basal forebrain (cBF) in the modulation of auditory cortical responses. This study aimed to accurately define the sources of cBF input to primary auditory cortex (AI) and to assess the efficacy of a cholinergic immunotoxin in cat. Three anaesthetized cats received multiple injections of horseradish-peroxidase conjugated wheatgerm-agglutin into physiologically identified AI. Following one to two days survival, tetramethylbenzidine histochemistry revealed the greatest number of retrogradely labeled cells in ipsilateral putamen, globus pallidus and internal capsule, and smaller numbers in more medial nuclei of the basal forebrain (BF). Concurrent choline acetyltransferase immunohistochemistry showed that almost 80% of the retrogradely labeled cells in BF were cholinergic, with the vast majority of these cells arising from the more lateral BF nuclei identified above. In the second part of the study, unilateral intraparenchymal injections of the cholinergic immunotoxin ME20.4-SAP were made into the putamen/globus pallidus nuclei of six cats. Immuno- and histochemistry revealed a massive reduction in the number of cholinergic cells in and around the targeted area, and a corresponding reduction in the density of cholinergic fibers in auditory cortex. These results are discussed in terms of their implications for investigations of the role of the cBF in cortical plasticity.

  8. Song exposure regulates known and novel microRNAs in the zebra finch auditory forebrain

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    Kim Jong H

    2011-05-01

    Full Text Available Abstract Background In an important model for neuroscience, songbirds learn to discriminate songs they hear during tape-recorded playbacks, as demonstrated by song-specific habituation of both behavioral and neurogenomic responses in the auditory forebrain. We hypothesized that microRNAs (miRNAs or miRs may participate in the changing pattern of gene expression induced by song exposure. To test this, we used massively parallel Illumina sequencing to analyse small RNAs from auditory forebrain of adult zebra finches exposed to tape-recorded birdsong or silence. Results In the auditory forebrain, we identified 121 known miRNAs conserved in other vertebrates. We also identified 34 novel miRNAs that do not align to human or chicken genomes. Five conserved miRNAs showed significant and consistent changes in copy number after song exposure across three biological replications of the song-silence comparison, with two increasing (tgu-miR-25, tgu-miR-192 and three decreasing (tgu-miR-92, tgu-miR-124, tgu-miR-129-5p. We also detected a locus on the Z sex chromosome that produces three different novel miRNAs, with supporting evidence from Northern blot and TaqMan qPCR assays for differential expression in males and females and in response to song playbacks. One of these, tgu-miR-2954-3p, is predicted (by TargetScan to regulate eight song-responsive mRNAs that all have functions in cellular proliferation and neuronal differentiation. Conclusions The experience of hearing another bird singing alters the profile of miRNAs in the auditory forebrain of zebra finches. The response involves both known conserved miRNAs and novel miRNAs described so far only in the zebra finch, including a novel sex-linked, song-responsive miRNA. These results indicate that miRNAs are likely to contribute to the unique behavioural biology of learned song communication in songbirds.

  9. Auditory adaptation improves tactile frequency perception.

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    Crommett, Lexi E; Pérez-Bellido, Alexis; Yau, Jeffrey M

    2017-01-11

    Our ability to process temporal frequency information by touch underlies our capacity to perceive and discriminate surface textures. Auditory signals, which also provide extensive temporal frequency information, can systematically alter the perception of vibrations on the hand. How auditory signals shape tactile processing is unclear: perceptual interactions between contemporaneous sounds and vibrations are consistent with multiple neural mechanisms. Here we used a crossmodal adaptation paradigm, which separated auditory and tactile stimulation in time, to test the hypothesis that tactile frequency perception depends on neural circuits that also process auditory frequency. We reasoned that auditory adaptation effects would transfer to touch only if signals from both senses converge on common representations. We found that auditory adaptation can improve tactile frequency discrimination thresholds. This occurred only when adaptor and test frequencies overlapped. In contrast, auditory adaptation did not influence tactile intensity judgments. Thus, auditory adaptation enhances touch in a frequency- and feature-specific manner. A simple network model in which tactile frequency information is decoded from sensory neurons that are susceptible to auditory adaptation recapitulates these behavioral results. Our results imply that the neural circuits supporting tactile frequency perception also process auditory signals. This finding is consistent with the notion of supramodal operators performing canonical operations, like temporal frequency processing, regardless of input modality.

  10. Auditory streaming by phase relations between components of harmonic complexes: a comparative study of human subjects and bird forebrain neurons.

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    Dolležal, Lena-Vanessa; Itatani, Naoya; Günther, Stefanie; Klump, Georg M

    2012-12-01

    Auditory streaming describes a percept in which a sequential series of sounds either is segregated into different streams or is integrated into one stream based on differences in their spectral or temporal characteristics. This phenomenon has been analyzed in human subjects (psychophysics) and European starlings (neurophysiology), presenting harmonic complex (HC) stimuli with different phase relations between their frequency components. Such stimuli allow evaluating streaming by temporal cues, as these stimuli only vary in the temporal waveform but have identical amplitude spectra. The present study applied the commonly used ABA- paradigm (van Noorden, 1975) and matched stimulus sets in psychophysics and neurophysiology to evaluate the effects of fundamental frequency (f₀), frequency range (f(LowCutoff)), tone duration (TD), and tone repetition time (TRT) on streaming by phase relations of the HC stimuli. By comparing the percept of humans with rate or temporal responses of avian forebrain neurons, a neuronal correlate of perceptual streaming of HC stimuli is described. The differences in the pattern of the neurons' spike rate responses provide for a better explanation for the percept observed in humans than the differences in the temporal responses (i.e., the representation of the periodicity in the timing of the action potentials). Especially for HC stimuli with a short 40-ms duration, the differences in the pattern of the neurons' temporal responses failed to represent the patterns of human perception, whereas the neurons' rate responses showed a good match. These results suggest that differential rate responses are a better predictor for auditory streaming by phase relations than temporal responses.

  11. Auditory filters at low-frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado; Pedersen, Christian Sejer; Møller, Henrik

    2009-01-01

    Prediction and assessment of low-frequency noise problems requires information about the auditory filter characteristics at low-frequencies. Unfortunately, data at low-frequencies is scarce and practically no results have been published for frequencies below 100 Hz. Extrapolation of ERB results......-ear transfer function), the asymmetry of the auditory filter changed from steeper high-frequency slopes at 1000 Hz to steeper low-frequency slopes below 100 Hz. Increasing steepness at low-frequencies of the middle-ear high-pass filter is thought to cause this effect. The dynamic range of the auditory filter...

  12. Measuring Auditory Selective Attention using Frequency Tagging

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    Hari M Bharadwaj

    2014-02-01

    Full Text Available Frequency tagging of sensory inputs (presenting stimuli that fluctuate periodically at rates to which the cortex can phase lock has been used to study attentional modulation of neural responses to inputs in different sensory modalities. For visual inputs, the visual steady-state response (VSSR at the frequency modulating an attended object is enhanced, while the VSSR to a distracting object is suppressed. In contrast, the effect of attention on the auditory steady-state response (ASSR is inconsistent across studies. However, most auditory studies analyzed results at the sensor level or used only a small number of equivalent current dipoles to fit cortical responses. In addition, most studies of auditory spatial attention used dichotic stimuli (independent signals at the ears rather than more natural, binaural stimuli. Here, we asked whether these methodological choices help explain discrepant results. Listeners attended to one of two competing speech streams, one simulated from the left and one from the right, that were modulated at different frequencies. Using distributed source modeling of magnetoencephalography results, we estimate how spatially directed attention modulates the ASSR in neural regions across the whole brain. Attention enhances the ASSR power at the frequency of the attended stream in the contralateral auditory cortex. The attended-stream modulation frequency also drives phase-locked responses in the left (but not right precentral sulcus (lPCS, a region implicated in control of eye gaze and visual spatial attention. Importantly, this region shows no phase locking to the distracting stream suggesting that the lPCS in engaged in an attention-specific manner. Modeling results that take account of the geometry and phases of the cortical sources phase locked to the two streams (including hemispheric asymmetry of lPCS activity help partly explain why past ASSR studies of auditory spatial attention yield seemingly contradictory

  13. Auditory place theory and frequency difference limen

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jialu

    2006-01-01

    It has been a barrier that the place code is far too coarse a mechanism to account for the finest frequency difference limen for place theory of hearing since it was proposed in 19th century. A place correlation model, which takes the energy distribution of a pure tone in neighboring bands of auditory filters into full account, was presented in this paper. The model based on the place theory and some experimental results of the psychophysical tuning curves of hearing can explain the finest difference limen for frequency (about 0.02 or 0.3% at 1000 Hz)easily. Using a standard 1/3 octave filter bank of which the relationship between the frequency of a input pure tone apart from the centre frequency of K-th filter band, △f, and the output intensity difference between K-th and (K + 1)-th filters, △E, was established in order to show the fine frequency detection ability of the filter bank. This model can also be used to abstract the fundamental frequency of speech and to measure the frequency of pure tone precisely.

  14. Across frequency processes involved in auditory detection of coloration

    DEFF Research Database (Denmark)

    Buchholz, Jörg; Kerketsos, P

    2008-01-01

    When an early wall reflection is added to a direct sound, a spectral modulation is introduced to the signal's power spectrum. This spectral modulation typically produces an auditory sensation of coloration or pitch. Throughout this study, auditory spectral-integration effects involved in coloration...... detection are investigated. Coloration detection thresholds were therefore measured as a function of reflection delay and stimulus bandwidth. In order to investigate the involved auditory mechanisms, an auditory model was employed that was conceptually similar to the peripheral weighting model [Yost, JASA......, 1982, 416-425]. When a “classical” gammatone filterbank was applied within this spectrum-based model, the model largely underestimated human performance at high signal frequencies. However, this limitation could be resolved by employing an auditory filterbank with narrower filters. This novel...

  15. Frequency-specific modulation of population-level frequency tuning in human auditory cortex

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    Roberts Larry E

    2009-01-01

    Full Text Available Abstract Background Under natural circumstances, attention plays an important role in extracting relevant auditory signals from simultaneously present, irrelevant noises. Excitatory and inhibitory neural activity, enhanced by attentional processes, seems to sharpen frequency tuning, contributing to improved auditory performance especially in noisy environments. In the present study, we investigated auditory magnetic fields in humans that were evoked by pure tones embedded in band-eliminated noises during two different stimulus sequencing conditions (constant vs. random under auditory focused attention by means of magnetoencephalography (MEG. Results In total, we used identical auditory stimuli between conditions, but presented them in a different order, thereby manipulating the neural processing and the auditory performance of the listeners. Constant stimulus sequencing blocks were characterized by the simultaneous presentation of pure tones of identical frequency with band-eliminated noises, whereas random sequencing blocks were characterized by the simultaneous presentation of pure tones of random frequencies and band-eliminated noises. We demonstrated that auditory evoked neural responses were larger in the constant sequencing compared to the random sequencing condition, particularly when the simultaneously presented noises contained narrow stop-bands. Conclusion The present study confirmed that population-level frequency tuning in human auditory cortex can be sharpened in a frequency-specific manner. This frequency-specific sharpening may contribute to improved auditory performance during detection and processing of relevant sound inputs characterized by specific frequency distributions in noisy environments.

  16. Auditory streaming of tones of uncertain frequency, level, and duration.

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    Chang, An-Chieh; Lutfi, Robert A; Lee, Jungmee

    2015-12-01

    Stimulus uncertainty is known to critically affect auditory masking, but its influence on auditory streaming has been largely ignored. Standard ABA-ABA tone sequences were made increasingly uncertain by increasing the sigma of normal distributions from which the frequency, level, or duration of tones were randomly drawn. Consistent with predictions based on a model of masking by Lutfi, Gilbertson, Chang, and Stamas [J. Acoust. Soc. Am. 134, 2160-2170 (2013)], the frequency difference for which A and B tones formed separate streams increased as a linear function of sigma in tone frequency but was much less affected by sigma in tone level or duration.

  17. The Study of Frequency Self Care Strategies against Auditory Hallucinations

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    Mahin Nadem

    2012-03-01

    Full Text Available Background: In schizophrenic clients, self-care strategies against auditory hallucinations can decrease disturbances results in hallucination. This study was aimed to assess frequency of self-care strategies against auditory hallucinations in paranoid schizophrenic patients, hospitalized in Shafa Hospital.Materials and Method: This was a descriptive study on 201 patients with paranoid schizophrenia hospitalized in psychiatry unit with convenience sampling in Rasht. The gathered data consists of two parts, first unit demographic characteristic and the second part, self- report questionnaire include 38 items about self-care strategies.Results: There were statistically significant relationship between demographic variables and knowledg effect and self-care strategies against auditory hallucinaions. Sex with phisical domain p0.07, marriage status with cognitive domain (p>0.07 and life status with behavioural domain (p>0.01. 53.2% of reported type of our auditory hallucinations were command hallucinations, furtheremore the most effective self-care strategies against auditory hallucinations were from physical domain and substance abuse (82.1% was the most effective strategies in this domain.Conclusion: The client with paranoid schizophrenia used more than physical domain strategies against auditory hallucinaions and this result highlight need those to approprait nursing intervention. Instruction and leading about selection the effective self-care strategies against auditory ha

  18. Neural responses in songbird forebrain reflect learning rates, acquired salience, and stimulus novelty after auditory discrimination training.

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    Bell, Brittany A; Phan, Mimi L; Vicario, David S

    2015-03-01

    How do social interactions form and modulate the neural representations of specific complex signals? This question can be addressed in the songbird auditory system. Like humans, songbirds learn to vocalize by imitating tutors heard during development. These learned vocalizations are important in reproductive and social interactions and in individual recognition. As a model for the social reinforcement of particular songs, male zebra finches were trained to peck for a food reward in response to one song stimulus (GO) and to withhold responding for another (NoGO). After performance reached criterion, single and multiunit neural responses to both trained and novel stimuli were obtained from multiple electrodes inserted bilaterally into two songbird auditory processing areas [caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM)] of awake, restrained birds. Neurons in these areas undergo stimulus-specific adaptation to repeated song stimuli, and responses to familiar stimuli adapt more slowly than to novel stimuli. The results show that auditory responses differed in NCM and CMM for trained (GO and NoGO) stimuli vs. novel song stimuli. When subjects were grouped by the number of training days required to reach criterion, fast learners showed larger neural responses and faster stimulus-specific adaptation to all stimuli than slow learners in both areas. Furthermore, responses in NCM of fast learners were more strongly left-lateralized than in slow learners. Thus auditory responses in these sensory areas not only encode stimulus familiarity, but also reflect behavioral reinforcement in our paradigm, and can potentially be modulated by social interactions.

  19. Multiscale mapping of frequency sweep rate in mouse auditory cortex.

    Science.gov (United States)

    Issa, John B; Haeffele, Benjamin D; Young, Eric D; Yue, David T

    2017-02-01

    Functional organization is a key feature of the neocortex that often guides studies of sensory processing, development, and plasticity. Tonotopy, which arises from the transduction properties of the cochlea, is the most widely studied organizational feature in auditory cortex; however, in order to process complex sounds, cortical regions are likely specialized for higher order features. Here, motivated by the prevalence of frequency modulations in mouse ultrasonic vocalizations and aided by the use of a multiscale imaging approach, we uncover a functional organization across the extent of auditory cortex for the rate of frequency modulated (FM) sweeps. In particular, using two-photon Ca(2+) imaging of layer 2/3 neurons, we identify a tone-insensitive region at the border of AI and AAF. This central sweep region behaves fundamentally differently from nearby neurons in AI and AII, responding preferentially to fast FM sweeps but not to tones or bandlimited noise. Together these findings define a second dimension of organization in the mouse auditory cortex for sweep rate complementary to that of tone frequency.

  20. Auditory brainstem responses predict auditory nerve fiber thresholds and frequency selectivity in hearing impaired chinchillas.

    Science.gov (United States)

    Henry, Kenneth S; Kale, Sushrut; Scheidt, Ryan E; Heinz, Michael G

    2011-10-01

    Noninvasive auditory brainstem responses (ABRs) are commonly used to assess cochlear pathology in both clinical and research environments. In the current study, we evaluated the relationship between ABR characteristics and more direct measures of cochlear function. We recorded ABRs and auditory nerve (AN) single-unit responses in seven chinchillas with noise-induced hearing loss. ABRs were recorded for 1-8 kHz tone burst stimuli both before and several weeks after 4 h of exposure to a 115 dB SPL, 50 Hz band of noise with a center frequency of 2 kHz. Shifts in ABR characteristics (threshold, wave I amplitude, and wave I latency) following hearing loss were compared to AN-fiber tuning curve properties (threshold and frequency selectivity) in the same animals. As expected, noise exposure generally resulted in an increase in ABR threshold and decrease in wave I amplitude at equal SPL. Wave I amplitude at equal sensation level (SL), however, was similar before and after noise exposure. In addition, noise exposure resulted in decreases in ABR wave I latency at equal SL and, to a lesser extent, at equal SPL. The shifts in ABR characteristics were significantly related to AN-fiber tuning curve properties in the same animal at the same frequency. Larger shifts in ABR thresholds and ABR wave I amplitude at equal SPL were associated with greater AN threshold elevation. Larger reductions in ABR wave I latency at equal SL, on the other hand, were associated with greater loss of AN frequency selectivity. This result is consistent with linear systems theory, which predicts shorter time delays for broader peripheral frequency tuning. Taken together with other studies, our results affirm that ABR thresholds and wave I amplitude provide useful estimates of cochlear sensitivity. Furthermore, comparisons of ABR wave I latency to normative data at the same SL may prove useful for detecting and characterizing loss of cochlear frequency selectivity.

  1. Frequency Transformation in the Auditory Lemniscal Thalamocortical System.

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    Kazuo eImaizumi

    2014-07-01

    Full Text Available The auditory lemniscal thalamocortical (TC pathway conveys information from the ventral division of the medial geniculate body to the primary auditory cortex (A1. Although their general topographic organization has been well characterized, functional transformations at the lemniscal TC synapse still remain incompletely codified, largely due to the need for integration of functional anatomical results with the variability observed with various animal models and experimental techniques. In this review, we discuss these issues with classical approaches, such as in vivo extracellular recordings and tracer injections to physiologically identified areas in A1, and then compare these studies with modern approaches, such as in vivo two-photon calcium imaging, in vivo whole-cell recordings, optogenetic methods, and in vitro methods using slice preparations. A surprising finding from a comparison of classical and modern approaches is the similar degree of convergence from thalamic neurons to single A1 neurons and clusters of A1 neurons, although, thalamic convergence to single A1 neurons is more restricted areas within putative thalamic frequency lamina. These comparisons suggest that frequency convergence from thalamic input to A1 is functionally limited. Finally, we consider synaptic organization of TC projections and future directions for research.

  2. Effects of frequency and level on auditory stream segregation.

    Science.gov (United States)

    Rose, M M; Moore, B C

    2000-09-01

    This study examined the effect of center frequency and level on the perceptual grouping of rapid tone sequences. The sequence ABA-ABA-...was used, where A and B represent sinusoidal tone bursts (10-ms rise/fall, 80-ms steady state, 20-ms interval between tones) and - represents a silent interval of 120 ms. In experiment 1, tone A was fixed in frequency at 62, 125, 250, 500, 1000, 2000, 4000, 6000, or 8000 Hz. Both tones had a level of approximately 40 dB SL. Tone B started with a frequency well above that of tone A, and its frequency was swept toward that of tone A so that the frequency separation between them decreased in an exponential manner. Subjects were required to indicate when they could no longer hear the tones A and B as two separate streams, but heard only a single stream with a "gallop" rhythm. This changeover point between percepts is called the fission boundary. The separation between tones A and B at the fission boundary was roughly independent of the frequency of tone A when expressed as the difference in number of equivalent rectangular bandwidths (ERBs) between A and B, but varied more with frequency when the difference was expressed in barks or cents. In experiment 2, the center frequency was fixed at 250, 1000, or 4000 Hz, and the level of the A and B tones was 40, 55, 70, or 85 dB SPL. The frequency separation of the A and B tones at the fission boundary tended to increase slightly with increasing level, in a manner consistent with the broadening of the auditory filter with increasing level. The results support the "peripheral channeling" explanation of stream segregation advanced by Hartmann and Johnson [Music Percept. 9, 155-184 (1991)], and indicate that the perception of fusion or fission in alternating-tone sequences depends partly upon the degree of overlap of the excitation patterns evoked by the successive sounds in the cochlea, as assumed in the theory of Beauvois and Meddis [J. Acoust. Soc. Am. 99, 2270-2280 (1996)].

  3. Auditory phase and frequency discrimination: a comparison of nine procedures.

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    Creelman, C D; Macmillan, N A

    1979-02-01

    Two auditory discrimination tasks were thoroughly investigated: discrimination of frequency differences from a sinusoidal signal of 200 Hz and discrimination of differences in relative phase of mixed sinusoids of 200 Hz and 400 Hz. For each task psychometric functions were constructed for three observers, using nine different psychophysical measurement procedures. These procedures included yes-no, two-interval forced-choice, and various fixed- and variable-standard designs that investigators have used in recent years. The data showed wide ranges of apparent sensitivity. For frequency discrimination, models derived from signal detection theory for each psychophysical procedure seem to account for the performance differences. For phase discrimination the models do not account for the data. We conclude that for some discriminative continua the assumptions of signal detection theory are appropriate, and underlying sensitivity may be derived from raw data by appropriate transformations. For other continua the models of signal detection theory are probably inappropriate; we speculate that phase might be discriminable only on the basis of comparison or change and suggest some tests of our hypothesis.

  4. Compensating Level-Dependent Frequency Representation in Auditory Cortex by Synaptic Integration of Corticocortical Input

    Science.gov (United States)

    Happel, Max F. K.; Ohl, Frank W.

    2017-01-01

    Robust perception of auditory objects over a large range of sound intensities is a fundamental feature of the auditory system. However, firing characteristics of single neurons across the entire auditory system, like the frequency tuning, can change significantly with stimulus intensity. Physiological correlates of level-constancy of auditory representations hence should be manifested on the level of larger neuronal assemblies or population patterns. In this study we have investigated how information of frequency and sound level is integrated on the circuit-level in the primary auditory cortex (AI) of the Mongolian gerbil. We used a combination of pharmacological silencing of corticocortically relayed activity and laminar current source density (CSD) analysis. Our data demonstrate that with increasing stimulus intensities progressively lower frequencies lead to the maximal impulse response within cortical input layers at a given cortical site inherited from thalamocortical synaptic inputs. We further identified a temporally precise intercolumnar synaptic convergence of early thalamocortical and horizontal corticocortical inputs. Later tone-evoked activity in upper layers showed a preservation of broad tonotopic tuning across sound levels without shifts towards lower frequencies. Synaptic integration within corticocortical circuits may hence contribute to a level-robust representation of auditory information on a neuronal population level in the auditory cortex. PMID:28046062

  5. Immediate effects of different frequencies of auditory stimulation on lower limb motor function of healthy people

    Science.gov (United States)

    Yu, Lili; Huang, Qiuchen; Hu, Chunying; Ye, Miao

    2016-01-01

    [Purpose] The purpose of this study was to explore the immediate effects of different frequencies of auditory stimulation on the lower limb motor function of healthy people. [Subjects and Methods] The subjects were 7 healthy people (5 males and 2 females). The subjects’ lower limb function was measured without auditory stimulation (control), and with auditory stimulation of 500, 1,000, 1,500, and 2,000 Hz. The measured parameters were maximum knee extension torque, average knee extension torque, the Timed Up and Go test (TUG) time, Functional Reach (FR), and the 10-meter walking time. [Results] The TUG times of 500, 1,500, and 2,000 Hz auditory stimulation showed significant decreases compared to the control. The 10-m walking times of 1,000 and 2,000 Hz auditory stimulation showed significant decreases compared to the control. [Conclusion] The results show that auditory stimulation improved the TUG and 10-meter walking times of healthy people and that different frequencies of auditory stimulation had different effects on lower limb motor function. PMID:27630392

  6. Frequency Selectivity Behaviour in the Auditory Midbrain: Implications of Model Study

    Institute of Scientific and Technical Information of China (English)

    KUANG Shen-Bing; WANG Jia-Fu; ZENG Ting

    2006-01-01

    By numerical simulations on frequency dependence of the spiking threshold, i.e. on the critical amplitude of periodic stimulus, for a neuron to fire, we find that bushy cells in the cochlear nuclear exhibit frequency selectivity behaviour. However, the selective frequency band of a bushy cell is far away from that of the preferred spectral range in human and mammal auditory perception. The mechanism underlying this neural activity is also discussed. Further studies show that the ion channel densities have little impact on the selective frequency band of bushy cells. These findings suggest that the neuronal behaviour of frequency selectivity in bushy cells at both the single cell and population levels may be not functionally relevant to frequency discrimination. Our results may reveal a neural hint to the reconsideration on the bushy cell functional role in auditory information processing of sound frequency.

  7. Frequency Selectivity Behaviour in the Auditory Midbrain: Implications of Model Study

    Science.gov (United States)

    Kuang, Shen-Bing; Wang, Jia-Fu; Zeng, Ting

    2006-12-01

    By numerical simulations on frequency dependence of the spiking threshold, i.e. on the critical amplitude of periodic stimulus, for a neuron to fire, we find that bushy cells in the cochlear nuclear exhibit frequency selectivity behaviour. However, the selective frequency band of a bushy cell is far away from that of the preferred spectral range in human and mammal auditory perception. The mechanism underlying this neural activity is also discussed. Further studies show that the ion channel densities have little impact on the selective frequency band of bushy cells. These findings suggest that the neuronal behaviour of frequency selectivity in bushy cells at both the single cell and population levels may be not functionally relevant to frequency discrimination. Our results may reveal a neural hint to the reconsideration on the bushy cell functional role in auditory information processing of sound frequency.

  8. Selective attention modulates human auditory brainstem responses: relative contributions of frequency and spatial cues.

    Directory of Open Access Journals (Sweden)

    Alexandre Lehmann

    Full Text Available Selective attention is the mechanism that allows focusing one's attention on a particular stimulus while filtering out a range of other stimuli, for instance, on a single conversation in a noisy room. Attending to one sound source rather than another changes activity in the human auditory cortex, but it is unclear whether attention to different acoustic features, such as voice pitch and speaker location, modulates subcortical activity. Studies using a dichotic listening paradigm indicated that auditory brainstem processing may be modulated by the direction of attention. We investigated whether endogenous selective attention to one of two speech signals affects amplitude and phase locking in auditory brainstem responses when the signals were either discriminable by frequency content alone, or by frequency content and spatial location. Frequency-following responses to the speech sounds were significantly modulated in both conditions. The modulation was specific to the task-relevant frequency band. The effect was stronger when both frequency and spatial information were available. Patterns of response were variable between participants, and were correlated with psychophysical discriminability of the stimuli, suggesting that the modulation was biologically relevant. Our results demonstrate that auditory brainstem responses are susceptible to efferent modulation related to behavioral goals. Furthermore they suggest that mechanisms of selective attention actively shape activity at early subcortical processing stages according to task relevance and based on frequency and spatial cues.

  9. Bilateral collicular interaction: modulation of auditory signal processing in frequency domain.

    Science.gov (United States)

    Cheng, L; Mei, H-X; Tang, J; Fu, Z-Y; Jen, P H-S; Chen, Q-C

    2013-04-01

    In the ascending auditory pathway, the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from a variety of lower auditory nuclei, intrinsic projections within the IC, contralateral IC through the commissure of the IC and the auditory cortex. All these connections make the IC a major center for subcortical temporal and spectral integration of auditory information. In this study, we examine bilateral collicular interaction in the modulation of frequency-domain signal processing of mice using electrophysiological recording and focal electrical stimulation. Focal electrical stimulation of neurons in one IC produces widespread inhibition and focused facilitation of responses of neurons in the other IC. This bilateral collicular interaction decreases the response magnitude and lengthens the response latency of inhibited IC neurons but produces an opposite effect on the response of facilitated IC neurons. In the frequency domain, the focal electrical stimulation of one IC sharpens or expands the frequency tuning curves (FTCs) of neurons in the other IC to improve frequency sensitivity and the frequency response range. The focal electrical stimulation also produces a shift in the best frequency (BF) of modulated IC (ICMdu) neurons toward that of electrically stimulated IC (ICES) neurons. The degree of bilateral collicular interaction is dependent upon the difference in the BF between the ICES neurons and ICMdu neurons. These data suggest that bilateral collicular interaction is a part of dynamic acoustic signal processing that adjusts and improves signal processing as well as reorganizes collicular representation of signal parameters according to the acoustic experience.

  10. Selective attention modulates human auditory brainstem responses: relative contributions of frequency and spatial cues.

    Science.gov (United States)

    Lehmann, Alexandre; Schönwiesner, Marc

    2014-01-01

    Selective attention is the mechanism that allows focusing one's attention on a particular stimulus while filtering out a range of other stimuli, for instance, on a single conversation in a noisy room. Attending to one sound source rather than another changes activity in the human auditory cortex, but it is unclear whether attention to different acoustic features, such as voice pitch and speaker location, modulates subcortical activity. Studies using a dichotic listening paradigm indicated that auditory brainstem processing may be modulated by the direction of attention. We investigated whether endogenous selective attention to one of two speech signals affects amplitude and phase locking in auditory brainstem responses when the signals were either discriminable by frequency content alone, or by frequency content and spatial location. Frequency-following responses to the speech sounds were significantly modulated in both conditions. The modulation was specific to the task-relevant frequency band. The effect was stronger when both frequency and spatial information were available. Patterns of response were variable between participants, and were correlated with psychophysical discriminability of the stimuli, suggesting that the modulation was biologically relevant. Our results demonstrate that auditory brainstem responses are susceptible to efferent modulation related to behavioral goals. Furthermore they suggest that mechanisms of selective attention actively shape activity at early subcortical processing stages according to task relevance and based on frequency and spatial cues.

  11. Auditory cortical areas activated by slow frequency-modulated sounds in mice.

    Directory of Open Access Journals (Sweden)

    Yuusuke Honma

    Full Text Available Species-specific vocalizations in mice have frequency-modulated (FM components slower than the lower limit of FM direction selectivity in the core region of the mouse auditory cortex. To identify cortical areas selective to slow frequency modulation, we investigated tonal responses in the mouse auditory cortex using transcranial flavoprotein fluorescence imaging. For differentiating responses to frequency modulation from those to stimuli at constant frequencies, we focused on transient fluorescence changes after direction reversal of temporally repeated and superimposed FM sweeps. We found that the ultrasonic field (UF in the belt cortical region selectively responded to the direction reversal. The dorsoposterior field (DP also responded weakly to the reversal. Regarding the responses in UF, no apparent tonotopic map was found, and the right UF responses were significantly larger in amplitude than the left UF responses. The half-max latency in responses to FM sweeps was shorter in UF compared with that in the primary auditory cortex (A1 or anterior auditory field (AAF. Tracer injection experiments in the functionally identified UF and DP confirmed that these two areas receive afferent inputs from the dorsal part of the medial geniculate nucleus (MG. Calcium imaging of UF neurons stained with fura-2 were performed using a two-photon microscope, and the presence of UF neurons that were selective to both direction and direction reversal of slow frequency modulation was demonstrated. These results strongly suggest a role for UF, and possibly DP, as cortical areas specialized for processing slow frequency modulation in mice.

  12. Relation between derived-band auditory brainstem response latencies and behavioral frequency selectivity

    DEFF Research Database (Denmark)

    Strelcyk, Olaf; Christoforidis, Dimitrios; Dau, Torsten

    2009-01-01

    for some of the HI listeners. The behavioral auditory-filter bandwidths accounted for the across-listener variability in the ABR latencies: Cochlear response time decreased with increasing filter bandwidth, consistent with linear-system theory. The results link cochlear response time and frequency...

  13. Auditory Frequency Discrimination in Adults with Dyslexia: A Test of the Anchoring Hypothesis

    Science.gov (United States)

    Wijnen, Frank; Kappers, Astrid M. L.; Vlutters, Leoni D.; Winkel, Sven

    2012-01-01

    Purpose: A recent hypothesis ascribes dyslexia to a perceptual anchoring deficit. Supporting results have so far been obtained only in children with dyslexia and additional learning difficulties, but the hypothesis has been argued to apply to all individuals with dyslexia. Method: The authors measured auditory frequency discrimination thresholds…

  14. Broadened population-level frequency tuning in the auditory cortex of tinnitus patients

    Science.gov (United States)

    Sekiya, Kenichi; Takahashi, Mariko; Murakami, Shingo; Kakigi, Ryusuke

    2017-01-01

    Tinnitus is a phantom auditory perception without an external sound source and is one of the most common public health concerns that impair the quality of life of many individuals. However, its neural mechanisms remain unclear. We herein examined population-level frequency tuning in the auditory cortex of unilateral tinnitus patients with similar hearing levels in both ears using magnetoencephalography. We compared auditory-evoked neural activities elicited by a stimulation to the tinnitus and nontinnitus ears. Objective magnetoencephalographic data suggested that population-level frequency tuning corresponding to the tinnitus ear was significantly broader than that corresponding to the nontinnitus ear in the human auditory cortex. The results obtained support the hypothesis that pathological alterations in inhibitory neural networks play an important role in the perception of subjective tinnitus. NEW & NOTEWORTHY Although subjective tinnitus is one of the most common public health concerns that impair the quality of life of many individuals, no standard treatment or objective diagnostic method currently exists. We herein revealed that population-level frequency tuning was significantly broader in the tinnitus ear than in the nontinnitus ear. The results of the present study provide an insight into the development of an objective diagnostic method for subjective tinnitus. PMID:28053240

  15. Neuromagnetic auditory steady state response to chords: effect of frequency ratio.

    Science.gov (United States)

    Otsuka, Asuka; Yumoto, Masato; Kuriki, Shinya; Nakagawa, Seiji

    2013-01-01

    Perceptual degree of consonance or dissonance of a chord is known to be varied as a function of frequency ratio between tones composing the chord. It has been indicated that generation of a sense of dissonance is associated with the auditory steady-state response (ASSR) phase-locked to difference frequencies which are salient in the chords with complex frequency ratios. This study further investigated how the neuromagnetic ASSR would be modulated as a function of the frequency ratio when the acoustic properties of the difference frequency, to which the ASSR was synchronized, was identical in terms of its number, energy and frequency. Neuronal frequency characteristics intrinsic to the ASSR were compensated by utilizing responses to a SAM (Sinusoidally Amplitude Modulated) chirp tone sweeping through the corresponding frequency range. The results showed that ASSR was significantly smaller for the chords with simple frequency ratios than for those with complex frequency ratios. It indicates that the basic neuronal correlates underlying the sensation of consonance/dissonance might be associated with the attenuation rate applied to encode the input information through the afferent auditory pathway. Attentional gating of the thalamo-cortical function might also be one of the factors.

  16. Broadened population-level frequency tuning in human auditory cortex of portable music player users.

    Directory of Open Access Journals (Sweden)

    Hidehiko Okamoto

    Full Text Available Nowadays, many people use portable players to enrich their daily life with enjoyable music. However, in noisy environments, the player volume is often set to extremely high levels in order to drown out the intense ambient noise and satisfy the appetite for music. Extensive and inappropriate usage of portable music players might cause subtle damages in the auditory system, which are not behaviorally detectable in an early stage of the hearing impairment progress. Here, by means of magnetoencephalography, we objectively examined detrimental effects of portable music player misusage on the population-level frequency tuning in the human auditory cortex. We compared two groups of young people: one group had listened to music with portable music players intensively for a long period of time, while the other group had not. Both groups performed equally and normally in standard audiological examinations (pure tone audiogram, speech test, and hearing-in-noise test. However, the objective magnetoencephalographic data demonstrated that the population-level frequency tuning in the auditory cortex of the portable music player users was significantly broadened compared to the non-users, when attention was distracted from the auditory modality; this group difference vanished when attention was directed to the auditory modality. Our conclusion is that extensive and inadequate usage of portable music players could cause subtle damages, which standard behavioral audiometric measures fail to detect in an early stage. However, these damages could lead to future irreversible hearing disorders, which would have a huge negative impact on the quality of life of those affected, and the society as a whole.

  17. Layer specific sharpening of frequency tuning by selective attention in primary auditory cortex.

    Science.gov (United States)

    O'Connell, Monica Noelle; Barczak, Annamaria; Schroeder, Charles E; Lakatos, Peter

    2014-12-03

    Recent electrophysiological and neuroimaging studies provide converging evidence that attending to sounds increases the response selectivity of neuronal ensembles even at the first cortical stage of auditory stimulus processing in primary auditory cortex (A1). This is achieved by enhancement of responses in the regions that process attended frequency content, and by suppression of responses in the surrounding regions. The goals of our study were to define the extent to which A1 neuronal ensembles are involved in this process, determine its effect on the frequency tuning of A1 neuronal ensembles, and examine the involvement of the different cortical layers. To accomplish these, we analyzed laminar profiles of synaptic activity and action potentials recorded in A1 of macaques performing a rhythmic intermodal selective attention task. We found that the frequency tuning of neuronal ensembles was sharpened due to both increased gain at the preferentially processed or best frequency and increased response suppression at all other frequencies when auditory stimuli were attended. Our results suggest that these effects are due to a frequency-specific counterphase entrainment of ongoing delta oscillations, which predictively orchestrates opposite sign excitability changes across all of A1. This results in a net suppressive effect due to the large proportion of neuronal ensembles that do not specifically process the attended frequency content. Furthermore, analysis of laminar activation profiles revealed that although attention-related suppressive effects predominate the responses of supragranular neuronal ensembles, response enhancement is dominant in the granular and infragranular layers, providing evidence for layer-specific cortical operations in attentive stimulus processing.

  18. Volume Attenuation and High Frequency Loss as Auditory Depth Cues in Stereoscopic 3D Cinema

    Science.gov (United States)

    Manolas, Christos; Pauletto, Sandra

    2014-09-01

    Assisted by the technological advances of the past decades, stereoscopic 3D (S3D) cinema is currently in the process of being established as a mainstream form of entertainment. The main focus of this collaborative effort is placed on the creation of immersive S3D visuals. However, with few exceptions, little attention has been given so far to the potential effect of the soundtrack on such environments. The potential of sound both as a means to enhance the impact of the S3D visual information and to expand the S3D cinematic world beyond the boundaries of the visuals is large. This article reports on our research into the possibilities of using auditory depth cues within the soundtrack as a means of affecting the perception of depth within cinematic S3D scenes. We study two main distance-related auditory cues: high-end frequency loss and overall volume attenuation. A series of experiments explored the effectiveness of these auditory cues. Results, although not conclusive, indicate that the studied auditory cues can influence the audience judgement of depth in cinematic 3D scenes, sometimes in unexpected ways. We conclude that 3D filmmaking can benefit from further studies on the effectiveness of specific sound design techniques to enhance S3D cinema.

  19. SPET monitoring of perfusion changes in auditory cortex following mono- and multi-frequency stimuli

    Energy Technology Data Exchange (ETDEWEB)

    De Rossi, G. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Paludetti, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Di Nardo, W. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Calcagni, M.L. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Di Giuda, D. [Nuclear Medicine Inst., Policlinico A. Gemelli, Rome (Italy); Almadori, G. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy); Galli, J. [Otorhinolaryngology Inst., Policlinico A. Gemelli, Rome (Italy)

    1996-08-01

    In order to assess the relationship between auditory cortex perfusion and the frequency of acoustic stimuli, twenty normally-hearing subjects underwent cerebral SPET. In 10 patients a multi-frequency stimulus (250-4000 Hz at 40 dB SL) was delivered, while 10 subjects were stimulated with a 500 Hz pure tone at 40 dB SL. The prestimulation SPET was subtracted from poststimulation study and auditory cortex activation was expressed as percent increments. Contralateral cortex was the most active area with multifrequency and monofrequency stimuli as well. A clear demonstration of a tonotopic distribution of acoustic stimuli in the auditory cortex was achieved. In addition, the accessory role played by homolateral accoustic areas was confirmed. The results of the present research support the hypothesis that brain SPET may be useful to obtain semiquantitative reliable information on low frequency auditory level in profoundly deaf patients. This may be achieved comparing the extension of the cortical areas activated by high-intensity multifrequency stimuli. (orig.) [Deutsch] Zur Aufklaerung der Beziehung von regionaler Perfusion des auditorischen Kortex und Frequenz des akustischen Stimulus wurden 20 Normalpatienten mit Hilfe von Hirn-SPECT untersucht. Bei je 10 Patienten wurde ein Multifrequenzstimulus (250-2000 Hz bei 60 dB) bzw. ein Monofrequenzstimulus (500 Hz bei 60 dB) verwendet. Die vor der Stimulation akquirierten SPECT-Daten wurden jeweils von den nach der Stimulation akquirierten SPECT-Daten abgezogen und die aditorische Kortexaktivation als prozentuale Steigerung ausgedrueckt. Der kontralaterale Kortex war das am staerksten aktivierte Areal sowohl bei der Multifrequenz- als auch bei der Monofrequenzstimulation. Es konnte eine klare tonotopische Verteilung der akustischen Stimuli im auditorischen Koretx demonstriert werden. Zusaetzlich konnte die akzessorische Rolle des homolateralen akustischen Kortex bestaetigt werden. Die Ergebnisse dieser Studie unterstuetzen

  20. Observations on auditory learning in amplitude- and frequency-modulation rate discrimination

    DEFF Research Database (Denmark)

    Hoffmann, Pablo F.

    2010-01-01

    Because amplitude- and frequency-modulated sounds can be the basis for the synthesis of many complex sounds, they can be good candidates in the design of training systems aiming at improving the acquisition of perceptual skills that can benefit from information provided via the auditory channel......-training, training, a post-training stages. During training, listeners were divided into two groups; one group trained on amplitude-modulation rate discrimination and the other group trained on frequency-modulation rate discrimination. Results will be discussed in terms of their implications for training...

  1. Parvalbumin-expressing inhibitory interneurons in auditory cortex are well-tuned for frequency.

    Science.gov (United States)

    Moore, Alexandra K; Wehr, Michael

    2013-08-21

    In the auditory cortex, synaptic inhibition is known to be involved in shaping receptive fields, enhancing temporal precision, and regulating gain. Cortical inhibition is provided by local GABAergic interneurons, which comprise 10-20% of the cortical population and can be separated into numerous subclasses. The morphological and physiological diversity of interneurons suggests that these different subclasses have unique roles in sound processing; however, these roles are yet unknown. Understanding the receptive field properties of distinct inhibitory cell types will be critical to elucidating their computational function in cortical circuits. Here we characterized the tuning and response properties of parvalbumin-positive (PV+) interneurons, the largest inhibitory subclass. We used channelrhodopsin-2 (ChR2) as an optogenetic tag to identify PV+ and PV- neurons in vivo in transgenic mice. In contrast to PV+ neurons in mouse visual cortex, which are broadly tuned for orientation, we found that auditory cortical PV+ neurons were well tuned for frequency, although very tightly tuned PV+ cells were uncommon. This suggests that PV+ neurons play a minor role in shaping frequency tuning, and is consistent with the idea that PV+ neurons nonselectively pool input from the local network. PV+ interneurons had shallower response gain and were less intensity-tuned than PV- neurons, suggesting that PV+ neurons provide dynamic gain control and shape intensity tuning in auditory cortex. PV+ neurons also had markedly faster response latencies than PV- neurons, consistent with a computational role in enhancing the temporal precision of cortical responses.

  2. A bio-inspired auditory perception model for amplitude-frequency clustering (keynote Paper)

    Science.gov (United States)

    Arena, Paolo; Fortuna, Luigi; Frasca, Mattia; Ganci, Gaetana; Patane, Luca

    2005-06-01

    In this paper a model for auditory perception is introduced. This model is based on a network of integrate-and-fire and resonate-and-fire neurons and is aimed to control the phonotaxis behavior of a roving robot. The starting point is the model of phonotaxis in Gryllus Bimaculatus: the model consists of four integrate-and-fire neurons and is able of discriminating the calling song of male cricket and orienting the robot towards the sound source. This paper aims to extend the model to include an amplitude-frequency clustering. The proposed spiking network shows different behaviors associated with different characteristics of the input signals (amplitude and frequency). The behavior implemented on the robot is similar to the cricket behavior, where some frequencies are associated with the calling song of male crickets, while other ones indicate the presence of predators. Therefore, the whole model for auditory perception is devoted to control different responses (attractive or repulsive) depending on the input characteristics. The performance of the control system has been evaluated with several experiments carried out on a roving robot.

  3. Frequency tuning of individual auditory receptors in female mosquitoes (Diptera, Culicidae).

    Science.gov (United States)

    Lapshin, D N; Vorontsov, D D

    2013-08-01

    The acoustic sensory organs in mosquitoes (Johnston organs) have been thoroughly studied; yet, to date, no data are available on the individual tuning properties of the numerous receptors that convert sound-induced vibrations into electrical signals. All previous measurements of frequency tuning in mosquitoes have been based on the acoustically evoked field potentials recorded from the entire Johnston organ. Here, we present evidence that individual receptors have various frequency tunings and that differently tuned receptors are unequally represented within the Johnston organ. We devised a positive feedback stimulation paradigm as a new and effective approach to test individual receptor properties. Alongside the glass microelectrode technique, the positive feedback stimulation paradigm has allowed us to obtain data on receptor tuning in females from three mosquito species: Anopheles messeae, Aedes excrucians and Culex pipiens pipiens. The existence of individually tuned auditory receptors implies that frequency analysis in mosquitoes may be possible.

  4. Frequency processing at consecutive levels in the auditory system of bush crickets (tettigoniidae).

    Science.gov (United States)

    Ostrowski, Tim Daniel; Stumpner, Andreas

    2010-08-01

    We asked how processing of male signals in the auditory pathway of the bush cricket Ancistrura nigrovittata (Phaneropterinae, Tettigoniidae) changes from the ear to the brain. From 37 sensory neurons in the crista acustica single elements (cells 8 or 9) have frequency tuning corresponding closely to the behavioral tuning of the females. Nevertheless, one-quarter of sensory neurons (approximately cells 9 to 18) excite the ascending neuron 1 (AN1), which is best tuned to the male's song carrier frequency. AN1 receives frequency-dependent inhibition, reducing sensitivity especially in the ultrasound. When recorded in the brain, AN1 shows slightly lower overall activity than when recorded in the prothoracic ganglion close to the spike-generating zone. This difference is significant in the ultrasonic range. The first identified local brain neuron in a bush cricket (LBN1) is described. Its dendrites overlap with some of AN1-terminations in the brain. Its frequency tuning and intensity dependence strongly suggest a direct postsynaptic connection to AN1. Spiking in LBN1 is only elicited after summation of excitatory postsynaptic potentials evoked by individual AN1-action potentials. This serves a filtering mechanism that reduces the sensitivity of LBN1 and also its responsiveness to ultrasound as compared to AN1. Consequently, spike latencies of LBN1 are long (>30 ms) despite its being a second-order interneuron. Additionally, LBN1 receives frequency-specific inhibition, most likely further reducing its responses to ultrasound. This demonstrates that frequency-specific inhibition is redundant in two directly connected interneurons on subsequent levels in the auditory system.

  5. Spike-frequency adaptation generates intensity invariance in a primary auditory interneuron.

    Science.gov (United States)

    Benda, Jan; Hennig, R Matthias

    2008-04-01

    Adaptation of the spike-frequency response to constant stimulation, as observed on various timescales in many neurons, reflects high-pass filter properties of a neuron's transfer function. Adaptation in general, however, is not sufficient to make a neuron's response independent of the mean intensity of a sensory stimulus, since low frequency components of the stimulus are still transmitted, although with reduced gain. We here show, based on an analytically tractable model, that the response of a neuron is intensity invariant, if the fully adapted steady-state spike-frequency response to constant stimuli is independent of stimulus intensity. Electrophysiological recordings from the AN1, a primary auditory interneuron of crickets, show that for intensities above 60 dB SPL (sound pressure level) the AN1 adapted with a time-constant of approximately 40 ms to a steady-state firing rate of approximately 100 Hz. Using identical random amplitude-modulation stimuli we verified that the AN1's spike-frequency response is indeed invariant to the stimulus' mean intensity above 60 dB SPL. The transfer function of the AN1 is a band pass, resulting from a high-pass filter (cutoff frequency at 4 Hz) due to adaptation and a low-pass filter (100 Hz) determined by the steady-state spike frequency. Thus, fast spike-frequency adaptation can generate intensity invariance already at the first level of neural processing.

  6. Tone frequency maps and receptive fields in the developing chinchilla auditory cortex.

    Science.gov (United States)

    Pienkowski, Martin; Harrison, Robert V

    2005-01-01

    Single-unit responses to tone pip stimuli were isolated from numerous microelectrode penetrations of auditory cortex (under ketamine anesthesia) in the developing chinchilla (laniger), a precocious mammal. Results are reported at postnatal day 3 (P3), P15, and P30, and from adult animals. Hearing sensitivity and spike firing rates were mature in the youngest group. The topographic representation of sound frequency (tonotopic map) in primary and secondary auditory cortex was also well ordered and sharply tuned by P3. The spectral-temporal complexity of cortical receptive fields, on the other hand, increased progressively (past P30) to adulthood. The (purported) refinement of initially diffuse tonotopic projections to cortex thus seems to occur in utero in the chinchilla, where external (and maternal) sounds are considerably attenuated and might not contribute to the mechanism(s) involved. This compares well with recent studies of vision, suggesting that the refinement of the retinotopic map does not require external light, but rather waves of (correlated) spontaneous activity on the retina. In contrast, it is most probable that selectivity for more complex sound features, such as frequency stacks and glides, develops under the influence of the postnatal acoustic environment and that inadequate sound stimulation in early development (e.g., due to chronic middle ear disease) impairs the formation of the requisite intracortical (and/or subcortical) circuitry.

  7. Representation of complex vocalizations in the Lusitanian toadfish auditory system: evidence of fine temporal, frequency and amplitude discrimination

    Science.gov (United States)

    Vasconcelos, Raquel O.; Fonseca, Paulo J.; Amorim, M. Clara P.; Ladich, Friedrich

    2011-01-01

    Many fishes rely on their auditory skills to interpret crucial information about predators and prey, and to communicate intraspecifically. Few studies, however, have examined how complex natural sounds are perceived in fishes. We investigated the representation of conspecific mating and agonistic calls in the auditory system of the Lusitanian toadfish Halobatrachus didactylus, and analysed auditory responses to heterospecific signals from ecologically relevant species: a sympatric vocal fish (meagre Argyrosomus regius) and a potential predator (dolphin Tursiops truncatus). Using auditory evoked potential (AEP) recordings, we showed that both sexes can resolve fine features of conspecific calls. The toadfish auditory system was most sensitive to frequencies well represented in the conspecific vocalizations (namely the mating boatwhistle), and revealed a fine representation of duration and pulsed structure of agonistic and mating calls. Stimuli and corresponding AEP amplitudes were highly correlated, indicating an accurate encoding of amplitude modulation. Moreover, Lusitanian toadfish were able to detect T. truncatus foraging sounds and A. regius calls, although at higher amplitudes. We provide strong evidence that the auditory system of a vocal fish, lacking accessory hearing structures, is capable of resolving fine features of complex vocalizations that are probably important for intraspecific communication and other relevant stimuli from the auditory scene. PMID:20861044

  8. Notched-noise embedded frequency specific chirps for objective audiometry using auditory brainstem responses

    Directory of Open Access Journals (Sweden)

    Farah I. Corona-Strauss

    2012-02-01

    Full Text Available It has been shown recently that chirp-evoked auditory brainstem responses (ABRs show better performance than click stimulations, especially at low intensity levels. In this paper we present the development, test, and evaluation of a series of notched-noise embedded frequency specific chirps. ABRs were collected in healthy young control subjects using the developed stimuli. Results of the analysis of the corresponding ABRs using a time-scale phase synchronization stability (PSS measure are also reported. The resultant wave V amplitude and latency measures showed a similar behavior as for values reported in literature. The PSS of frequency specific chirp-evoked ABRs reflected the presence of the wave V for all stimulation intensities. The scales that resulted in higher PSS are in line with previous findings, where ABRs evoked by broadband chirps were analyzed, and which stated that low frequency channels are better for the recognition and analysis of chirp-evoked ABRs. We conclude that the development and test of the series of notched-noise embedded frequency specific chirps allowed the assessment of frequency specific ABRs, showing an identifiable wave V for different intensity levels. Future work may include the development of a faster automatic recognition scheme for these frequency specific ABRs.

  9. Instantaneous and Frequency-Warped Signal Processing Techniques for Auditory Source Separation.

    Science.gov (United States)

    Wang, Avery Li-Chun

    This thesis summarizes several contributions to the areas of signal processing and auditory source separation. The philosophy of Frequency-Warped Signal Processing is introduced as a means for separating the AM and FM contributions to the bandwidth of a complex-valued, frequency-varying sinusoid p (n), transforming it into a signal with slowly-varying parameters. This transformation facilitates the removal of p (n) from an additive mixture while minimizing the amount of damage done to other signal components. The average winding rate of a complex-valued phasor is explored as an estimate of the instantaneous frequency. Theorems are provided showing the robustness of this measure. To implement frequency tracking, a Frequency-Locked Loop algorithm is introduced which uses the complex winding error to update its frequency estimate. The input signal is dynamically demodulated and filtered to extract the envelope. This envelope may then be remodulated to reconstruct the target partial, which may be subtracted from the original signal mixture to yield a new, quickly-adapting form of notch filtering. Enhancements to the basic tracker are made which, under certain conditions, attain the Cramer -Rao bound for the instantaneous frequency estimate. To improve tracking, the novel idea of Harmonic -Locked Loop tracking, using N harmonically constrained trackers, is introduced for tracking signals, such as voices and certain musical instruments. The estimated fundamental frequency is computed from a maximum-likelihood weighting of the N tracking estimates, making it highly robust. The result is that harmonic signals, such as voices, can be isolated from complex mixtures in the presence of other spectrally overlapping signals. Additionally, since phase information is preserved, the resynthesized harmonic signals may be removed from the original mixtures with relatively little damage to the residual signal. Finally, a new methodology is given for designing linear-phase FIR filters

  10. High frequency rTMS; a more effective treatment for auditory verbal hallucinations?

    Science.gov (United States)

    de Weijer, Antoin D; Sommer, Iris E C; Lotte Meijering, Anne; Bloemendaal, Mirjam; Neggers, Sebastiaan F W; Daalman, Kirstin; Boezeman, Eduard H J F

    2014-12-30

    The great majority of studies on repetitive transcranial magnetic stimulation (rTMS) as a therapeutic tool for auditory verbal hallucinations (AVH) have used 1-Hz stimulation with inconsistent results. Recently, it has been suggested that 20-Hz rTMS has strong therapeutic effects. It is conceivable that this 20-Hz stimulation is more effective than 1-Hz stimulation. The aim of this preliminary study is to investigate the efficacy of 20-Hz rTMS compared with 1-Hz rTMS as a treatment for AVH. Eighteen schizophrenia patients with medication-resistant AVH were randomized over two treatment groups. Each group received either 20 min of 1-Hz rTMS or 13 trains of 20-Hz rTMS daily over 1 week. After week 1, patients received a follow-up treatment once a week for 3 weeks. Stimulation location was based on individual AVH-related activation patterns identified with functional magnetic resonance imaging. Severity of AVH was monitored with the Auditory Hallucination Rating Scale (AHRS). Both groups showed a decrease in AVH after week 1 of rTMS. This decrease was significant for the 20-Hz group and the 1-Hz group. When the two treatment types were compared, no treatment type was superior. Based on these results we cannot conclude whether high frequency rTMS is more effective against AVH than is traditional 1-Hz rTMS. More research is needed to optimize stimulation parameters and to investigate potential target locations for stimulation.

  11. Comparisons of Stuttering Frequency during and after Speech Initiation in Unaltered Feedback, Altered Auditory Feedback and Choral Speech Conditions

    Science.gov (United States)

    Saltuklaroglu, Tim; Kalinowski, Joseph; Robbins, Mary; Crawcour, Stephen; Bowers, Andrew

    2009-01-01

    Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate…

  12. Structure and Topology Dynamics of Hyper-Frequency Networks during Rest and Auditory Oddball Performance.

    Science.gov (United States)

    Müller, Viktor; Perdikis, Dionysios; von Oertzen, Timo; Sleimen-Malkoun, Rita; Jirsa, Viktor; Lindenberger, Ulman

    2016-01-01

    Resting-state and task-related recordings are characterized by oscillatory brain activity and widely distributed networks of synchronized oscillatory circuits. Electroencephalographic recordings (EEG) were used to assess network structure and network dynamics during resting state with eyes open and closed, and auditory oddball performance through phase synchronization between EEG channels. For this assessment, we constructed a hyper-frequency network (HFN) based on within- and cross-frequency coupling (WFC and CFC, respectively) at 10 oscillation frequencies ranging between 2 and 20 Hz. We found that CFC generally differentiates between task conditions better than WFC. CFC was the highest during resting state with eyes open. Using a graph-theoretical approach (GTA), we found that HFNs possess small-world network (SWN) topology with a slight tendency to random network characteristics. Moreover, analysis of the temporal fluctuations of HFNs revealed specific network topology dynamics (NTD), i.e., temporal changes of different graph-theoretical measures such as strength, clustering coefficient, characteristic path length (CPL), local, and global efficiency determined for HFNs at different time windows. The different topology metrics showed significant differences between conditions in the mean and standard deviation of these metrics both across time and nodes. In addition, using an artificial neural network approach, we found stimulus-related dynamics that varied across the different network topology metrics. We conclude that functional connectivity dynamics (FCD), or NTD, which was found using the HFN approach during rest and stimulus processing, reflects temporal and topological changes in the functional organization and reorganization of neuronal cell assemblies.

  13. High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

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    Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

    2015-12-01

    Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery.

  14. A randomized, sham-controlled study of high frequency rTMS for auditory hallucination in schizophrenia.

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    Kimura, Hiroshi; Kanahara, Nobuhisa; Takase, Masayuki; Yoshida, Taisuke; Watanabe, Hiroyuki; Iyo, Masaomi

    2016-07-30

    Chronic auditory verbal hallucinations (AVHs) in patients with schizophrenia are sometimes resistant to standard pharmacotherapy. Repetitive transcranial magnetic stimulation (rTMS) may be a promising treatment modality for AVHs, but the best protocol has yet to be identified. We used a double-blind randomized sham-controlled design aimed at 30 patients (active group N=16 vs. sham group N=14) with chronic AVHs that persisted regardless of adequate pharmacotherapy. The protocol was a total of four sessions of high-frequency (20-Hz) rTMS targeting the left temporoparietal cortex over 2 days (total 10,400 stimulations) administered to each patient. After the rTMS session the patients were followed for 4 weeks and evaluated with the Auditory Hallucination Rating Scale (AHRS). The mean changes of AHRS score were 22.9 (baseline) to 18.4 (4th week) in the Active group and 24.2 (baseline) to 21.8 (4th week) in the Sham group, indicating no significant difference by mix model analysis. As regards other secondary end points (each subscore of AHRS, BPRS, GAF and CGI-S), none of these parameters showed a significant between-group difference. The present study's rTMS protocol was ineffective for our patients. However, several previous studies demonstrated that high-frequency rTMS is a possible strategy to ameliorate pharmacotherapy-resistant AVH. It is important to establish a high-frequency rTMS protocol with more reliability.

  15. Abnormal auditory mismatch response in tinnitus sufferers with high-frequency hearing loss is associated with subjective distress level

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    Berg Patrick

    2004-03-01

    Full Text Available Abstract Background Tinnitus is an auditory sensation frequently following hearing loss. After cochlear injury, deafferented neurons become sensitive to neighbouring intact edge-frequencies, guiding an enhanced central representation of these frequencies. As psychoacoustical data 123 indicate enhanced frequency discrimination ability for edge-frequencies that may be related to a reorganization within the auditory cortex, the aim of the present study was twofold: 1 to search for abnormal auditory mismatch responses in tinnitus sufferers and 2 relate these to subjective indicators of tinnitus. Results Using EEG-mismatch negativity, we demonstrate abnormalities (N = 15 in tinnitus sufferers that are specific to frequencies located at the audiometrically normal lesion-edge as compared to normal hearing controls (N = 15. Groups also differed with respect to the cortical locations of mismatch responsiveness. Sources in the 90–135 ms latency window were generated in more anterior brain regions in the tinnitus group. Both measures of abnormality correlated with emotional-cognitive distress related to tinnitus (r ~ .76. While these two physiological variables were uncorrelated in the control group, they were correlated in the tinnitus group (r = .72. Concerning relationships with parameters of hearing loss (depth and slope, slope turned out to be an important variable. Generally, the steeper the hearing loss is the less distress related to tinnitus was reported. The associations between slope and the relevant neurophysiological variables are in agreement with this finding. Conclusions The present study is the first to show near-to-complete separation of tinnitus sufferers from a normal hearing control group based on neurophysiological variables. The finding of lesion-edge specific effects and associations with slope of hearing loss corroborates the assumption that hearing loss is the basis for tinnitus development. It is likely that some central

  16. Testosterone alters genomic responses to song and monoaminergic innervation of auditory areas in a seasonally breeding songbird.

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    Matragrano, Lisa L; LeBlanc, Meredith M; Chitrapu, Anjani; Blanton, Zane E; Maney, Donna L

    2013-06-01

    Behavioral responses to social stimuli often vary according to endocrine state. Our previous work has suggested that such changes in behavior may be due in part to hormone-dependent sensory processing. In the auditory forebrain of female white-throated sparrows, expression of the immediate early gene ZENK (egr-1) is higher in response to conspecific song than to a control sound only when plasma estradiol reaches breeding-typical levels. Estradiol also increases the number of detectable noradrenergic neurons in the locus coeruleus and the density of noradrenergic and serotonergic fibers innervating auditory areas. We hypothesize, therefore, that reproductive hormones alter auditory responses by acting on monoaminergic systems. This possibility has not been examined in males. Here, we treated non-breeding male white-throated sparrows with testosterone to mimic breeding-typical levels and then exposed them to conspecific male song or frequency-matched tones. We observed selective ZENK responses in the caudomedial nidopallium only in the testosterone-treated males. Responses in another auditory area, the caudomedial mesopallium, were selective regardless of hormone treatment. Testosterone treatment reduced serotonergic fiber density in the auditory forebrain, thalamus, and midbrain, and although it increased the number of noradrenergic neurons detected in the locus coeruleus, it reduced noradrenergic fiber density in the auditory midbrain. Thus, whereas we previously reported that estradiol enhances monoaminergic innervation of the auditory pathway in females, we show here that testosterone decreases it in males. Mechanisms underlying testosterone-dependent selectivity of the ZENK response may differ from estradiol-dependent ones

  17. The neural code for auditory space depends on sound frequency and head size in an optimal manner.

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    Nicol S Harper

    Full Text Available A major cue to the location of a sound source is the interaural time difference (ITD-the difference in sound arrival time at the two ears. The neural representation of this auditory cue is unresolved. The classic model of ITD coding, dominant for a half-century, posits that the distribution of best ITDs (the ITD evoking a neuron's maximal response is unimodal and largely within the range of ITDs permitted by head-size. This is often interpreted as a place code for source location. An alternative model, based on neurophysiology in small mammals, posits a bimodal distribution of best ITDs with exquisite sensitivity to ITDs generated by means of relative firing rates between the distributions. Recently, an optimal-coding model was proposed, unifying the disparate features of these two models under the framework of efficient coding by neural populations. The optimal-coding model predicts that distributions of best ITDs depend on head size and sound frequency: for high frequencies and large heads it resembles the classic model, for low frequencies and small head sizes it resembles the bimodal model. The optimal-coding model makes key, yet unobserved, predictions: for many species, including humans, both forms of neural representation are employed, depending on sound frequency. Furthermore, novel representations are predicted for intermediate frequencies. Here, we examine these predictions in neurophysiological data from five mammalian species: macaque, guinea pig, cat, gerbil and kangaroo rat. We present the first evidence supporting these untested predictions, and demonstrate that different representations appear to be employed at different sound frequencies in the same species.

  18. The neural code for auditory space depends on sound frequency and head size in an optimal manner.

    Science.gov (United States)

    Harper, Nicol S; Scott, Brian H; Semple, Malcolm N; McAlpine, David

    2014-01-01

    A major cue to the location of a sound source is the interaural time difference (ITD)-the difference in sound arrival time at the two ears. The neural representation of this auditory cue is unresolved. The classic model of ITD coding, dominant for a half-century, posits that the distribution of best ITDs (the ITD evoking a neuron's maximal response) is unimodal and largely within the range of ITDs permitted by head-size. This is often interpreted as a place code for source location. An alternative model, based on neurophysiology in small mammals, posits a bimodal distribution of best ITDs with exquisite sensitivity to ITDs generated by means of relative firing rates between the distributions. Recently, an optimal-coding model was proposed, unifying the disparate features of these two models under the framework of efficient coding by neural populations. The optimal-coding model predicts that distributions of best ITDs depend on head size and sound frequency: for high frequencies and large heads it resembles the classic model, for low frequencies and small head sizes it resembles the bimodal model. The optimal-coding model makes key, yet unobserved, predictions: for many species, including humans, both forms of neural representation are employed, depending on sound frequency. Furthermore, novel representations are predicted for intermediate frequencies. Here, we examine these predictions in neurophysiological data from five mammalian species: macaque, guinea pig, cat, gerbil and kangaroo rat. We present the first evidence supporting these untested predictions, and demonstrate that different representations appear to be employed at different sound frequencies in the same species.

  19. Firing frequency and entrainment maintained in primary auditory neurons in the presence of combined BDNF and NT3.

    Science.gov (United States)

    Wright, Tess; Gillespie, Lisa N; O'Leary, Stephen J; Needham, Karina

    2016-06-23

    Primary auditory neurons rely on neurotrophic factors for development and survival. We previously determined that exposure to brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) alters the activity of hyperpolarization-activated currents (Ih) in this neuronal population. Since potassium channels are sensitive to neurotrophins, and changes in Ih are often accompanied by a shift in voltage-gated potassium currents (IK), this study examined IK with exposure to both BDNF and NT3 and the impact on firing entrainment during high frequency pulse trains. Whole-cell patch-clamp recordings revealed significant changes in action potential latency and duration, but no change in firing adaptation or total outward IK. Dendrotoxin-I (DTX-I), targeting voltage-gated potassium channel subunits KV1.1 and KV1.2, uncovered an increase in the contribution of DTX-I sensitive currents with exposure to neurotrophins. No difference in Phrixotoxin-1 (PaTX-1) sensitive currents, mediated by KV4.2 and KV4.3 subunits, was observed. Further, no difference was seen in firing entrainment. These results show that combined BDNF and NT3 exposure influences the contribution of KV1.1 and KV1.2 to the low voltage-activated potassium current (IKL). Whilst this is accompanied by a shift in spike latency and duration, both firing frequency and entrainment to high frequency pulse trains are preserved.

  20. Adapted wavelet transform improves time-frequency representations: a study of auditory elicited P300-like event-related potentials in rats

    Science.gov (United States)

    Richard, Nelly; Laursen, Bettina; Grupe, Morten; Drewes, Asbjørn M.; Graversen, Carina; Sørensen, Helge B. D.; Bastlund, Jesper F.

    2017-04-01

    Objective. Active auditory oddball paradigms are simple tone discrimination tasks used to study the P300 deflection of event-related potentials (ERPs). These ERPs may be quantified by time-frequency analysis. As auditory stimuli cause early high frequency and late low frequency ERP oscillations, the continuous wavelet transform (CWT) is often chosen for decomposition due to its multi-resolution properties. However, as the conventional CWT traditionally applies only one mother wavelet to represent the entire spectrum, the time-frequency resolution is not optimal across all scales. To account for this, we developed and validated a novel method specifically refined to analyse P300-like ERPs in rats. Approach. An adapted CWT (aCWT) was implemented to preserve high time-frequency resolution across all scales by commissioning of multiple wavelets operating at different scales. First, decomposition of simulated ERPs was illustrated using the classical CWT and the aCWT. Next, the two methods were applied to EEG recordings obtained from prefrontal cortex in rats performing a two-tone auditory discrimination task. Main results. While only early ERP frequency changes between responses to target and non-target tones were detected by the CWT, both early and late changes were successfully described with strong accuracy by the aCWT in rat ERPs. Increased frontal gamma power and phase synchrony was observed particularly within theta and gamma frequency bands during deviant tones. Significance. The study suggests superior performance of the aCWT over the CWT in terms of detailed quantification of time-frequency properties of ERPs. Our methodological investigation indicates that accurate and complete assessment of time-frequency components of short-time neural signals is feasible with the novel analysis approach which may be advantageous for characterisation of several types of evoked potentials in particularly rodents.

  1. Prolonged response to calling songs by the L3 auditory interneuron in female crickets (Acheta domesticus): possible roles in regulating phonotactic threshold and selectiveness for call carrier frequency.

    Science.gov (United States)

    Bronsert, Michael; Bingol, Hilary; Atkins, Gordon; Stout, John

    2003-03-01

    L3, an auditory interneuron in the prothoracic ganglion of female crickets (Acheta domesticus) exhibited two kinds of responses to models of the male's calling song (CS): a previously described, phasically encoded immediate response; a more tonically encoded prolonged response. The onset of the prolonged response required 3-8 sec of stimulation to reach its maximum spiking rate and 6-20 sec to decay once the calling song ceased. It did not encode the syllables of the chirp. The prolonged response was sharply selective for the 4-5 kHz carrier frequency of the male's calling songs and its threshold tuning matched the threshold tuning of phonotaxis, while the immediate response of the same neuron was broadly tuned to a wide range of carrier frequencies. The thresholds for the prolonged response covaried with the changing phonotactic thresholds of 2- and 5-day-old females. Treatment of females with juvenile hormone reduced the thresholds for both phonotaxis and the prolonged response by equivalent amounts. Of the 3 types of responses to CSs provided by the ascending L1 and L3 auditory interneurons, the threshold for L3's prolonged response, on average, best matched the same females phonotactic threshold. The prolonged response was stimulated by inputs from both ears while L3's immediate response was driven only from its axon-ipsilateral ear. The prolonged response was not selective for either the CS's syllable period or chirp rate.

  2. Finding your mate at a cocktail party: frequency separation promotes auditory stream segregation of concurrent voices in multi-species frog choruses.

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    Vivek Nityananda

    Full Text Available Vocal communication in crowded social environments is a difficult problem for both humans and nonhuman animals. Yet many important social behaviors require listeners to detect, recognize, and discriminate among signals in a complex acoustic milieu comprising the overlapping signals of multiple individuals, often of multiple species. Humans exploit a relatively small number of acoustic cues to segregate overlapping voices (as well as other mixtures of concurrent sounds, like polyphonic music. By comparison, we know little about how nonhuman animals are adapted to solve similar communication problems. One important cue enabling source segregation in human speech communication is that of frequency separation between concurrent voices: differences in frequency promote perceptual segregation of overlapping voices into separate "auditory streams" that can be followed through time. In this study, we show that frequency separation (ΔF also enables frogs to segregate concurrent vocalizations, such as those routinely encountered in mixed-species breeding choruses. We presented female gray treefrogs (Hyla chrysoscelis with a pulsed target signal (simulating an attractive conspecific call in the presence of a continuous stream of distractor pulses (simulating an overlapping, unattractive heterospecific call. When the ΔF between target and distractor was small (e.g., ≤3 semitones, females exhibited low levels of responsiveness, indicating a failure to recognize the target as an attractive signal when the distractor had a similar frequency. Subjects became increasingly more responsive to the target, as indicated by shorter latencies for phonotaxis, as the ΔF between target and distractor increased (e.g., ΔF = 6-12 semitones. These results support the conclusion that gray treefrogs, like humans, can exploit frequency separation as a perceptual cue to segregate concurrent voices in noisy social environments. The ability of these frogs to segregate

  3. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal.

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    McConnell, Patrick A; Froeliger, Brett; Garland, Eric L; Ives, Jeffrey C; Sforzo, Gary A

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics [heart rate variability (HRV)] during post-exercise relaxation. Subjects (n = 21; 18-29 years old) participated in a double-blind, placebo-controlled study during which binaural beats and placebo were administered over two randomized and counterbalanced sessions (within-subjects repeated-measures design). At the onset of each visit, subjects exercised for 20-min; post-exercise, subjects listened to either binaural beats ('wide-band' theta-frequency binaural beats) or placebo (carrier tones) for 20-min while relaxing alone in a quiet, low-light environment. Dependent variables consisted of high-frequency (HF, reflecting parasympathetic activity), low-frequency (LF, reflecting sympathetic and parasympathetic activity), and LF/HF normalized powers, as well as self-reported relaxation. As compared to the placebo visit, the binaural-beat visit resulted in greater self-reported relaxation, increased parasympathetic activation and increased sympathetic withdrawal. By the end of the 20-min relaxation period there were no observable differences in HRV between binaural-beat and placebo visits, although binaural-beat associated HRV significantly predicted subsequent reported relaxation. Findings suggest that listening to binaural beats may exert an acute influence on both LF and HF components of HRV and may increase subjective feelings of relaxation.

  4. The frequency modulated auditory evoked response (FMAER, a technical advance for study of childhood language disorders: cortical source localization and selected case studies

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    Duffy Frank H

    2013-01-01

    Full Text Available Abstract Background Language comprehension requires decoding of complex, rapidly changing speech streams. Detecting changes of frequency modulation (FM within speech is hypothesized as essential for accurate phoneme detection, and thus, for spoken word comprehension. Despite past demonstration of FM auditory evoked response (FMAER utility in language disorder investigations, it is seldom utilized clinically. This report's purpose is to facilitate clinical use by explaining analytic pitfalls, demonstrating sites of cortical origin, and illustrating potential utility. Results FMAERs collected from children with language disorders, including Developmental Dysphasia, Landau-Kleffner syndrome (LKS, and autism spectrum disorder (ASD and also normal controls - utilizing multi-channel reference-free recordings assisted by discrete source analysis - provided demonstratrions of cortical origin and examples of clinical utility. Recordings from inpatient epileptics with indwelling cortical electrodes provided direct assessment of FMAER origin. The FMAER is shown to normally arise from bilateral posterior superior temporal gyri and immediate temporal lobe surround. Childhood language disorders associated with prominent receptive deficits demonstrate absent left or bilateral FMAER temporal lobe responses. When receptive language is spared, the FMAER may remain present bilaterally. Analyses based upon mastoid or ear reference electrodes are shown to result in erroneous conclusions. Serial FMAER studies may dynamically track status of underlying language processing in LKS. FMAERs in ASD with language impairment may be normal or abnormal. Cortical FMAERs can locate language cortex when conventional cortical stimulation does not. Conclusion The FMAER measures the processing by the superior temporal gyri and adjacent cortex of rapid frequency modulation within an auditory stream. Clinical disorders associated with receptive deficits are shown to demonstrate absent

  5. Forebrain neurogenesis: From embryo to adult

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    Dennis, Daniel; Picketts, David; Slack, Ruth S.; Schuurmans, Carol

    2017-01-01

    A satellite symposium to the Canadian Developmental Biology Conference 2016 was held on March 16–17, 2016 in Banff, Alberta, Canada, entitled Forebrain Neurogenesis: From embryo to adult. The Forebrain Neurogenesis symposium was a focused, high-intensity meeting, bringing together the top Canadian and international researchers in the field. This symposium reported the latest breaking news, along with ‘state of the art’ techniques to answer fundamental questions in developmental neurobiology. Topics covered ranged from stem cell regulation to neurocircuitry development, culminating with a session focused on neuropsychiatric disorders. Understanding the underlying causes of neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) is of great interest as diagnoses of these conditions are climbing at alarming rates. For instance, in 2012, the Centers for Disease Control reported that the prevalence rate of ASD in the U.S. was 1 in 88; while more recent data indicate that the number is as high as 1 in 68 (Centers for Disease Control and Prevention MMWR Surveillance Summaries. Vol. 63. No. 2). Similarly, the incidence of ASD is on the rise in Canada, increasing from 1 in 150 in 2000 to 1 in 63 in 2012 in southeastern Ontario (Centers for Disease Control and Prevention). Currently very little is known regarding the deficits underlying these neurodevelopmental conditions. Moreover, the development of effective therapies is further limited by major gaps in our understanding of the fundamental processes that regulate forebrain development and adult neurogenesis. The Forebrain Neurogenesis satellite symposium was thus timely, and it played a key role in advancing research in this important field, while also fostering collaborations between international leaders, and inspiring young researchers.

  6. Microglia Modulate Wiring of the Embryonic Forebrain

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    Paola Squarzoni

    2014-09-01

    Full Text Available Dysfunction of microglia, the tissue macrophages of the brain, has been associated with the etiology of several neuropsychiatric disorders. Consistently, microglia have been shown to regulate neurogenesis and synaptic maturation at perinatal and postnatal stages. However, microglia invade the brain during mid-embryogenesis and thus could play an earlier prenatal role. Here, we show that embryonic microglia, which display a transiently uneven distribution, regulate the wiring of forebrain circuits. Using multiple mouse models, including cell-depletion approaches and cx3cr1−/−, CR3−/−, and DAP12−/− mutants, we find that perturbing microglial activity affects the outgrowth of dopaminergic axons in the forebrain and the laminar positioning of subsets of neocortical interneurons. Since defects in both dopamine innervation and cortical networks have been linked to neuropsychiatric diseases, our study provides insights into how microglial dysfunction can impact forebrain connectivity and reveals roles for immune cells during normal assembly of brain circuits.

  7. Auditory hallucinations.

    Science.gov (United States)

    Blom, Jan Dirk

    2015-01-01

    Auditory hallucinations constitute a phenomenologically rich group of endogenously mediated percepts which are associated with psychiatric, neurologic, otologic, and other medical conditions, but which are also experienced by 10-15% of all healthy individuals in the general population. The group of phenomena is probably best known for its verbal auditory subtype, but it also includes musical hallucinations, echo of reading, exploding-head syndrome, and many other types. The subgroup of verbal auditory hallucinations has been studied extensively with the aid of neuroimaging techniques, and from those studies emerges an outline of a functional as well as a structural network of widely distributed brain areas involved in their mediation. The present chapter provides an overview of the various types of auditory hallucination described in the literature, summarizes our current knowledge of the auditory networks involved in their mediation, and draws on ideas from the philosophy of science and network science to reconceptualize the auditory hallucinatory experience, and point out directions for future research into its neurobiologic substrates. In addition, it provides an overview of known associations with various clinical conditions and of the existing evidence for pharmacologic and non-pharmacologic treatments.

  8. Representation of spatial and spectro-temporal cues in the midbrain and forebrain of North American barn owls (Tyto furcata pratincola)

    OpenAIRE

    2015-01-01

    The barn owl is a crepuscular and nocturnal bird of prey that relies mainly on its acoustic system for the identification and localization of potential prey. The barn owl is able to localize even faint sounds in a natural environment precisely. Like mammals, barn owls use the interaural time difference (ITD) for the localization of the azimuthal sound source position. In the barn owl’s auditory system, ITD is processed in two separate pathways, the midbrain and forebrain pathways, which are b...

  9. Forebrain substrates of reward and motivation.

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    Wise, Roy A

    2005-12-01

    Electrical stimulation of the medial forebrain bundle can reward arbitrary acts or motivate biologically primitive, species-typical behaviors like feeding or copulation. The subsystems involved in these behaviors are only partially characterized, but they appear to transsynaptically activate the mesocorticolimbic dopamine system. Basal function of the dopamine system is essential for arousal and motor function; phasic activation of this system is rewarding and can potentiate the effectiveness of reward-predictors that guide learned behaviors. This system is phasically activated by most drugs of abuse and such activation contributes to the habit-forming actions of these drugs.

  10. The predictability of frequency-altered auditory feedback changes the weighting of feedback and feedforward input for speech motor control.

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    Scheerer, Nichole E; Jones, Jeffery A

    2014-12-01

    Speech production requires the combined effort of a feedback control system driven by sensory feedback, and a feedforward control system driven by internal models. However, the factors that dictate the relative weighting of these feedback and feedforward control systems are unclear. In this event-related potential (ERP) study, participants produced vocalisations while being exposed to blocks of frequency-altered feedback (FAF) perturbations that were either predictable in magnitude (consistently either 50 or 100 cents) or unpredictable in magnitude (50- and 100-cent perturbations varying randomly within each vocalisation). Vocal and P1-N1-P2 ERP responses revealed decreases in the magnitude and trial-to-trial variability of vocal responses, smaller N1 amplitudes, and shorter vocal, P1 and N1 response latencies following predictable FAF perturbation magnitudes. In addition, vocal response magnitudes correlated with N1 amplitudes, vocal response latencies, and P2 latencies. This pattern of results suggests that after repeated exposure to predictable FAF perturbations, the contribution of the feedforward control system increases. Examination of the presentation order of the FAF perturbations revealed smaller compensatory responses, smaller P1 and P2 amplitudes, and shorter N1 latencies when the block of predictable 100-cent perturbations occurred prior to the block of predictable 50-cent perturbations. These results suggest that exposure to large perturbations modulates responses to subsequent perturbations of equal or smaller size. Similarly, exposure to a 100-cent perturbation prior to a 50-cent perturbation within a vocalisation decreased the magnitude of vocal and N1 responses, but increased P1 and P2 latencies. Thus, exposure to a single perturbation can affect responses to subsequent perturbations.

  11. Calcium imaging of basal forebrain activity during innate and learned behaviors

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    Thomas Clarke Harrison

    2016-05-01

    Full Text Available The basal forebrain (BF plays crucial roles in arousal, attention, and memory, and its impairment is associated with a variety of cognitive deficits. The BF consists of cholinergic, GABAergic, and glutamatergic neurons. Electrical or optogenetic stimulation of BF cholinergic neurons enhances cortical processing and behavioral performance, but the natural activity of these cells during behavior is only beginning to be characterized. Even less is known about GABAergic and glutamatergic neurons. Here, we performed microendoscopic calcium imaging of BF neurons as mice engaged in spontaneous behaviors in their home cages (innate or performed a go/no-go auditory discrimination task (learned. Cholinergic neurons were consistently excited during movement, including running and licking, but GABAergic and glutamatergic neurons exhibited diverse responses. All cell types were activated by overt punishment, either inside or outside of the discrimination task. These findings reveal functional similarities and distinctions between BF cell types during both spontaneous and task-related behaviors.

  12. Perirhinal cortex relays auditory information to the frontal motor cortices in the rat.

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    Kyuhou, Shin-ichi; Matsuzaki, Ryuichi; Gemba, Hisae

    2003-12-26

    Auditory evoked potentials (AEPs) were recorded in the motor cortices (MC) with chronically implanted electrodes in the rat. Some of the AEPs in the MC, namely negative potentials on the surface and positive ones at a depth of 2 mm at latencies of about 50-150 ms, were abolished by limited bilateral lesions of the anterior perirhinal cortex (PERa) which was responsive to auditory stimulus, indicating that the AEPs in the MC were at least partially relayed in the PERa. The auditory response in the MC was prominently enhanced when water was supplied or the medial forebrain bundle was stimulated after auditory stimulus. These results indicate that the MC receives the reward associated auditory information from the PERa.

  13. Patterning of the chick forebrain anlage by the prechordal plate.

    Science.gov (United States)

    Pera, E M; Kessel, M

    1997-10-01

    We analysed the role of the prechordal plate in forebrain development of chick embryos in vivo. After transplantation to uncommitted ectoderm a prechordal plate induces an ectopic, dorsoventrally patterned, forebrain-like vesicle. Grafting laterally under the anterior neural plate causes ventralization of the lateral side of the forebrain, as indicated by a second expression domain of the homeobox gene NKX2.1. Such a lateral ventralization cannot be induced by the secreted factor Sonic Hedgehog alone, as this is only able to distort the ventral forebrain medially. Removal of the prechordal plate does not reduce the rostrocaudal extent of the anterior neural tube, but leads to significant narrowing and cyclopia. Excision of the head process results in the caudal expansion of the NKX2.1 expression in the ventral part of the anterior neural tube, while PAX6 expression in the dorsal part remains unchanged. We suggest that there are three essential steps in early forebrain patterning, which culminate in the ventralization of the forebrain. First, anterior neuralization occurs at the primitive streak stage, when BMP-4-antagonizing factors emanate from the node and spread in a planar fashion to induce anterior neural ectoderm. Second, the anterior translocation of organizer-derived cells shifts the source of neuralizing factors anteriorly, where the relative concentration of BMP-4-antagonists is thus elevated, and the medial part of the prospective forebrain becomes competent to respond to ventralizing factors. Third, the forebrain anlage is ventralized by signals including Sonic Hedgehog, thereby creating a new identity, the prospective hypothalamus, which splits the eye anlage into two lateral domains.

  14. Auditory Hallucination

    Directory of Open Access Journals (Sweden)

    MohammadReza Rajabi

    2003-09-01

    Full Text Available Auditory Hallucination or Paracusia is a form of hallucination that involves perceiving sounds without auditory stimulus. A common is hearing one or more talking voices which is associated with psychotic disorders such as schizophrenia or mania. Hallucination, itself, is the most common feature of perceiving the wrong stimulus or to the better word perception of the absence stimulus. Here we will discuss four definitions of hallucinations:1.Perceiving of a stimulus without the presence of any subject; 2. hallucination proper which are the wrong perceptions that are not the falsification of real perception, Although manifest as a new subject and happen along with and synchronously with a real perception;3. hallucination is an out-of-body perception which has no accordance with a real subjectIn a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid, substantial, and located in external objective space. We are going to discuss it in details here.

  15. Mosaic Subventricular Origins of Forebrain Oligodendrogenesis

    Science.gov (United States)

    Azim, Kasum; Berninger, Benedikt; Raineteau, Olivier

    2016-01-01

    In the perinatal as well as the adult CNS, the subventricular zone (SVZ) of the forebrain is the largest and most active source of neural stem cells (NSCs) that generates neurons and oligodendrocytes (OLs), the myelin forming cells of the CNS. Recent advances in the field are beginning to shed light regarding SVZ heterogeneity, with the existence of spatially segregated microdomains that are intrinsically biased to generate phenotypically distinct neuronal populations. Although most research has focused on this regionalization in the context of neurogenesis, newer findings underline that this also applies for the genesis of OLs under the control of specific patterning molecules. In this mini review, we discuss the origins as well as the mechanisms that induce and maintain SVZ regionalization. These come in the flavor of specific signaling ligands and subsequent initiation of transcriptional networks that provide a basis for subdividing the SVZ into distinct lineage-specific microdomains. We further emphasize canonical Wnts and FGF2 as essential signaling pathways for the regional genesis of OL progenitors from NSCs of the dorsal SVZ. This aspect of NSC biology, which has so far received little attention, may unveil new avenues for appropriately recruiting NSCs in demyelinating diseases. PMID:27047329

  16. Mosaic subventricular origins of forebrain oligodendroglia

    Directory of Open Access Journals (Sweden)

    Kasum eAzim

    2016-03-01

    Full Text Available In the perinatal as well as the adult CNS, the subventricular zone (SVZ of the forebrain is the largest and most active source of neural stem cells (NSCs that generates neurons and oligodendrocytes (OLs, the myelin forming cells of the CNS. Recent advances in the field are beginning to shed light regarding SVZ heterogeneity, with the existence of spatially segregated microdomains that are intrinsically biased to generate phenotypically distinct neuronal populations. Although most research has focused on this regionalization in the context of neurogenesis, newer findings underline that this also applies for the genesis of OLs under the control of specific patterning molecules. In this mini review, we discuss the origins as well as the mechanisms that induce and maintain SVZ regionalization. These come in the flavor of specific signaling ligands and subsequent initiation of transcriptional networks that provide a basis for subdividing the SVZ into distinct lineage-specific microdomains. We further emphasize canonical Wnt and FGF2 as essential signaling pathways for the regional genesis of OL progenitors from NSCs of the dorsal SVZ. This aspect of NSC biology, which has so far received little attention, may unveil new avenues for appropriately recruiting NSCs in demyelinating diseases.

  17. Current status of auditory aging and anti-aging research.

    Science.gov (United States)

    Ruan, Qingwei; Ma, Cheng; Zhang, Ruxin; Yu, Zhuowei

    2014-01-01

    The development of presbycusis, or age-related hearing loss, is determined by a combination of genetic and environmental factors. The auditory periphery exhibits a progressive bilateral, symmetrical reduction of auditory sensitivity to sound from high to low frequencies. The central auditory nervous system shows symptoms of decline in age-related cognitive abilities, including difficulties in speech discrimination and reduced central auditory processing, ultimately resulting in auditory perceptual abnormalities. The pathophysiological mechanisms of presbycusis include excitotoxicity, oxidative stress, inflammation, aging and oxidative stress-induced DNA damage that results in apoptosis in the auditory pathway. However, the originating signals that trigger these mechanisms remain unclear. For instance, it is still unknown whether insulin is involved in auditory aging. Auditory aging has preclinical lesions, which manifest as asymptomatic loss of periphery auditory nerves and changes in the plasticity of the central auditory nervous system. Currently, the diagnosis of preclinical, reversible lesions depends on the detection of auditory impairment by functional imaging, and the identification of physiological and molecular biological markers. However, despite recent improvements in the application of these markers, they remain under-utilized in clinical practice. The application of antisenescent approaches to the prevention of auditory aging has produced inconsistent results. Future research will focus on the identification of markers for the diagnosis of preclinical auditory aging and the development of effective interventions.

  18. Auditory Hallucinations in Acute Stroke

    Directory of Open Access Journals (Sweden)

    Yair Lampl

    2005-01-01

    Full Text Available Auditory hallucinations are uncommon phenomena which can be directly caused by acute stroke, mostly described after lesions of the brain stem, very rarely reported after cortical strokes. The purpose of this study is to determine the frequency of this phenomenon. In a cross sectional study, 641 stroke patients were followed in the period between 1996–2000. Each patient underwent comprehensive investigation and follow-up. Four patients were found to have post cortical stroke auditory hallucinations. All of them occurred after an ischemic lesion of the right temporal lobe. After no more than four months, all patients were symptom-free and without therapy. The fact the auditory hallucinations may be of cortical origin must be taken into consideration in the treatment of stroke patients. The phenomenon may be completely reversible after a couple of months.

  19. Organization of the auditory brainstem in a lizard, Gekko gecko. I. Auditory nerve, cochlear nuclei, and superior olivary nuclei

    DEFF Research Database (Denmark)

    Tang, Y. Z.; Christensen-Dalsgaard, J.; Carr, C. E.

    2012-01-01

    We used tract tracing to reveal the connections of the auditory brainstem in the Tokay gecko (Gekko gecko). The auditory nerve has two divisions, a rostroventrally directed projection of mid- to high best-frequency fibers to the nucleus angularis (NA) and a more dorsal and caudal projection of lo...... of auditory connections in lizards and archosaurs but also different processing of low- and high-frequency information in the brainstem. J. Comp. Neurol. 520:17841799, 2012. (C) 2011 Wiley Periodicals, Inc...

  20. Distribution of synapses on two ascending interneurones carrying frequency-specific information in the auditory system of the cricket: evidence for GABAergic inputs.

    Science.gov (United States)

    Hardt, M; Watson, A H

    1994-07-22

    Two identified cricket auditory interneurones, AN1 and AN2, were intracellularly labelled with horseradish peroxidase following physiological characterisation. The neurones, which have some structural similarities, have their somata in the prothoracic ganglion and axons that project to the brain. Although both carry auditory information, they have different response properties and participate in different types of phonotactic behaviour. Ultrathin sections from selected regions of their prothoracic arborisations were examined in the electron microscope after postembedding immunostaining for the inhibitory transmitter GABA. In the prothoracic ganglion AN1 branches only in the medial ventral association centre (mVAC) contralateral to the soma, and receives only iput synapses. Twenty-seven percent of these were made by processes immunoreactive for GABA. AN2 branches not only in mVAC on both sides of the ganglion but also in several other areas. It makes output synapses from large diameter neurites in mVAC on both sides of the ganglion as well as from neurites in more posterior regions of the neuropile. Most input synapses are received onto branches in the contralateral mVAC where about 19% were made from GABA-immunoreactive processes.

  1. Representation of Reward Feedback in Primate Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Michael eBrosch

    2011-02-01

    Full Text Available It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1 the reward expectancy for each trial, (2 the reward size received and (3 the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  2. Representation of reward feedback in primate auditory cortex.

    Science.gov (United States)

    Brosch, Michael; Selezneva, Elena; Scheich, Henning

    2011-01-01

    It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1) the reward expectancy for each trial, (2) the reward-size received, and (3) the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

  3. Chick homeobox gene cDlx expression demarcates the forebrain anlage, indicating the onset of forebrain regional specification at gastrulation.

    Science.gov (United States)

    Borghjid, S; Siddiqui, M A

    2000-01-01

    Here we describe the isolation and characterization of a chick homeobox-containing gene, cDlx, which shows greater than 85% homology to the homeodomain of other vertebrate Distal-less genes. Northern blot analysis and in situ hybridization studies reveal that cDlx expression is developmentally regulated and is tissue specific. In particular, the developmental expression pattern is characterized by an early appearance of cDlx transcript in the prospective forebrain region of gastrulating embryos. During neurulation, cDlx is consistently expressed in a spatially restricted domain in the presumptive ventral forebrain region of the neural plate that will give rise to the hypothalamus and the adenohypophysis. Our data support the notion that members of the Dlx gene family are part of a homeobox gene code in forebrain pattern formation and suggest that regional specification of the forebrain occurs at much earlier stages than previously thought. The homeobox gene cDlx may thus play a role in defining forebrain regional identity as early as gastrulation.

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  16. Dynamic expression of MEIS1 homeoprotein in E14.5 forebrain and differentiated forebrain-derived neural stem cells.

    Science.gov (United States)

    Barber, Benjamin A; Liyanage, Vichithra R B; Zachariah, Robby M; Olson, Carl O; Bailey, Melissa A G; Rastegar, Mojgan

    2013-10-01

    Central nervous system development is controlled by highly conserved homeoprotein transcription factors including HOX and TALE (Three Amino acid Loop Extension). TALE proteins are primarily known as HOX-cofactors and play key roles in cell proliferation, differentiation and organogenesis. MEIS1 is a TALE member with established expression in the developing central nervous system. MEIS1 is essential for embryonic development and Meis1 knockout mice dies at embryonic day (E) 14.5. However, Meis1/MEIS1 expression in the devolving forebrain, at this critical time-point has not been studied. Here, for the first time we characterize the region-specific expression of MEIS1 in E14.5 mouse forebrain, filling the gap of MEIS1 expression profile between E12.5 and E16.5. Previously, we reported MEIS1 transcriptional regulatory role in neuronal differentiation and established forebrain-derived neural stem cells (NSC) for gene therapy application of neuronal genes. Here, we show the dynamic expression of Meis1/MEIS1 during the differentiation of forebrain-derived NSC toward a glial lineage. Our results show that Meis1/MEIS1 expression is induced during NSC differentiation and is expressed in both differentiated neurons and astrocytes. Confirming these results, we detected MEIS1 expression in primary cultures of in vivo differentiated cortical neurons and astrocytes. We further demonstrate Meis1/MEIS1 expression relative to other TALE family members in the forebrain-derived NSC in the absence of Hox genes. Our data provide evidence that forebrain-derived NSC can be used as an accessible in vitro model to study the expression and function of TALE proteins, supporting their potential role in modulating NSC self-renewal and differentiation.

  17. Auditory Imagery: Empirical Findings

    Science.gov (United States)

    Hubbard, Timothy L.

    2010-01-01

    The empirical literature on auditory imagery is reviewed. Data on (a) imagery for auditory features (pitch, timbre, loudness), (b) imagery for complex nonverbal auditory stimuli (musical contour, melody, harmony, tempo, notational audiation, environmental sounds), (c) imagery for verbal stimuli (speech, text, in dreams, interior monologue), (d)…

  18. Forebrain Mechanisms of Nociception and Pain: Analysis through Imaging

    Science.gov (United States)

    Casey, Kenneth L.

    1999-07-01

    Pain is a unified experience composed of interacting discriminative, affective-motivational, and cognitive components, each of which is mediated and modulated through forebrain mechanisms acting at spinal, brainstem, and cerebral levels. The size of the human forebrain in relation to the spinal cord gives anatomical emphasis to forebrain control over nociceptive processing. Human forebrain pathology can cause pain without the activation of nociceptors. Functional imaging of the normal human brain with positron emission tomography (PET) shows synaptically induced increases in regional cerebral blood flow (rCBF) in several regions specifically during pain. We have examined the variables of gender, type of noxious stimulus, and the origin of nociceptive input as potential determinants of the pattern and intensity of rCBF responses. The structures most consistently activated across genders and during contact heat pain, cold pain, cutaneous laser pain or intramuscular pain were the contralateral insula and anterior cingulate cortex, the bilateral thalamus and premotor cortex, and the cerebellar vermis. These regions are commonly activated in PET studies of pain conducted by other investigators, and the intensity of the brain rCBF response correlates parametrically with perceived pain intensity. To complement the human studies, we developed an animal model for investigating stimulus-induced rCBF responses in the rat. In accord with behavioral measures and the results of human PET, there is a progressive and selective activation of somatosensory and limbic system structures in the brain and brainstem following the subcutaneous injection of formalin. The animal model and human PET studies should be mutually reinforcing and thus facilitate progress in understanding forebrain mechanisms of normal and pathological pain.

  19. Estradiol-dependent catecholaminergic innervation of auditory areas in a seasonally breeding songbird.

    Science.gov (United States)

    Matragrano, Lisa L; Sanford, Sara E; Salvante, Katrina G; Sockman, Keith W; Maney, Donna L

    2011-08-01

    A growing body of evidence suggests that gonadal steroids such as estradiol (E2) alter neural responses not only in brain regions associated with reproductive behavior but also in sensory areas. Because catecholamine systems are involved in sensory processing and selective attention, and because they are sensitive to E2 in many species, they may mediate the neural effects of E2 in sensory areas. Here, we tested the effects of E2 on catecholaminergic innervation, synthesis and activity in the auditory system of white-throated sparrows, a seasonally breeding songbird in which E2 promotes selective auditory responses to song. Non-breeding females with regressed ovaries were held on a winter-like photoperiod and implanted with silastic capsules containing either no hormone or E2. In one hemisphere of the brain, we used immunohistochemistry to quantify fibers immunoreactive for tyrosine hydroxylase or dopamine beta-hydroxylase in the auditory forebrain, thalamus and midbrain. E2 treatment increased catecholaminergic innervation in the same areas of the auditory system in which E2 promotes selectivity for song. In the contralateral hemisphere we quantified dopamine, norepinephrine and their metabolites in tissue punches using HPLC. Norepinephrine increased in the auditory forebrain, but not the midbrain, after E2 treatment. We found that evidence of interhemispheric differences, both in immunoreactivity and catecholamine content that did not depend on E2 treatment. Overall, our results show that increases in plasma E2 typical of the breeding season enhanced catecholaminergic innervation and synthesis in some parts of the auditory system, raising the possibility that catecholamines play a role in E2-dependent auditory plasticity in songbirds.

  20. Effect of stimulus hemifield on free-field auditory saltation.

    Science.gov (United States)

    Ishigami, Yoko; Phillips, Dennis P

    2008-07-01

    Auditory saltation is the orderly misperception of the spatial location of repetitive click stimuli emitted from two successive locations when the inter-click intervals (ICIs) are sufficiently short. The clicks are perceived as originating not only from the actual source locations, but also from locations between them. In two tasks, the present experiment compared free-field auditory saltation for 90 degrees excursions centered in the frontal, rear, left and right acoustic hemifields, by measuring the ICI at which subjects report 50% illusion strength (subjective task) and the ICI at which subjects could not distinguish real motion from saltation (objective task). A comparison of the saltation illusion for excursions spanning the midline (i.e. for frontal or rear hemifields) with that for stimuli in the lateral hemifields (left or right) revealed that the illusion was weaker for the midline-straddling conditions (i.e. the illusion was restricted to shorter ICIs). This may reflect the contribution of two perceptual channels to the task in the midline conditions (as opposed to one in the lateral hemifield conditions), or the fact that the temporal dynamics of localization differ between the midline and lateral hemifield conditions. A subsidiary comparison of saltation supported in the left and right auditory hemifields, and therefore by the right and left auditory forebrains, revealed no difference.

  1. Altered auditory BOLD response to conspecific birdsong in zebra finches with stuttered syllables.

    Directory of Open Access Journals (Sweden)

    Henning U Voss

    Full Text Available How well a songbird learns a song appears to depend on the formation of a robust auditory template of its tutor's song. Using functional magnetic resonance neuroimaging we examine auditory responses in two groups of zebra finches that differ in the type of song they sing after being tutored by birds producing stuttering-like syllable repetitions in their songs. We find that birds that learn to produce the stuttered syntax show attenuated blood oxygenation level-dependent (BOLD responses to tutor's song, and more pronounced responses to conspecific song primarily in the auditory area field L of the avian forebrain, when compared to birds that produce normal song. These findings are consistent with the presence of a sensory song template critical for song learning in auditory areas of the zebra finch forebrain. In addition, they suggest a relationship between an altered response related to familiarity and/or saliency of song stimuli and the production of variant songs with stuttered syllables.

  2. 年龄对言语诱发 ABR 的频率跟随反应影响%The Effects of Aging on Frequency Following Response in Speech Evoked Auditory Brainstem Response

    Institute of Scientific and Technical Information of China (English)

    郝文洋; 商莹莹; 倪道凤; 姜鸿; 徐春晓; 高志强; 王素菊; 李奉蓉; 赵翠霞

    2016-01-01

    Objective This study was to record the speech evoked auditory brainstem response (s-ABR) of normal hearing young and aged people ,then compared the frequency following responses (FFR) of s-ABR between the two groups ,in order to explore the contribution of FFR on revealing possible aging mechanisms of central audi‐tory system .Methods Twelve normal hearing young adults and aged people respectively (24 ears) were enrolled and s-ABRs (syllable/da/) were recorded using a SmartEP auditory evoked potential system .Results The comparison of waveforms between the two groups showed that the wave latencies of transient responses in the aged group was longer than that of young group ,while the wave latencies of the sustained response ,FFR ,were of no significant differences .The amplitudes of FFR waves in the aged group were lower than those of in the young group .The FFR spectrum analysis showed that the relative energy of each formant for the aged group was lower than that of in the young group and for some formants .Moreover ,for the aged group ,formant frequency differences between FFR and stimulus signal were greater than the young group .Conclusion Compared with young people ,the FFR of aged peo‐ple showed lower amplitudes and less accuracy ,meaning that aging can lead to the weakness of the brainstem neurons'spectral encoding ability .It may be one of the mechanisms causing the reduction of speech recognition in presbycusis patients .%目的:分析听力正常青年人与老年人之间言语诱发听性脑干反应(speech evoked auditory brainstem response ,s-ABR)的频率跟随反应(frequency following response ,FFR)差异,探讨其在揭示听觉系统老化机制中的作用。方法应用SmartEP听觉诱发电位系统对听力正常青年人(18~25岁)与老年人(60~70岁)各12例(24耳)进行言语声信号/da/诱发的s-ABR检测,比较两组s -ABR波形图及频谱图、FFR各波潜伏期及共振峰等。结

  3. Auditory sustained field responses to periodic noise

    Directory of Open Access Journals (Sweden)

    Keceli Sumru

    2012-01-01

    Full Text Available Abstract Background Auditory sustained responses have been recently suggested to reflect neural processing of speech sounds in the auditory cortex. As periodic fluctuations below the pitch range are important for speech perception, it is necessary to investigate how low frequency periodic sounds are processed in the human auditory cortex. Auditory sustained responses have been shown to be sensitive to temporal regularity but the relationship between the amplitudes of auditory evoked sustained responses and the repetitive rates of auditory inputs remains elusive. As the temporal and spectral features of sounds enhance different components of sustained responses, previous studies with click trains and vowel stimuli presented diverging results. In order to investigate the effect of repetition rate on cortical responses, we analyzed the auditory sustained fields evoked by periodic and aperiodic noises using magnetoencephalography. Results Sustained fields were elicited by white noise and repeating frozen noise stimuli with repetition rates of 5-, 10-, 50-, 200- and 500 Hz. The sustained field amplitudes were significantly larger for all the periodic stimuli than for white noise. Although the sustained field amplitudes showed a rising and falling pattern within the repetition rate range, the response amplitudes to 5 Hz repetition rate were significantly larger than to 500 Hz. Conclusions The enhanced sustained field responses to periodic noises show that cortical sensitivity to periodic sounds is maintained for a wide range of repetition rates. Persistence of periodicity sensitivity below the pitch range suggests that in addition to processing the fundamental frequency of voice, sustained field generators can also resolve low frequency temporal modulations in speech envelope.

  4. The Effect of Gender on the N1-P2 Auditory Complex while Listening and Speaking with Altered Auditory Feedback

    Science.gov (United States)

    Swink, Shannon; Stuart, Andrew

    2012-01-01

    The effect of gender on the N1-P2 auditory complex was examined while listening and speaking with altered auditory feedback. Fifteen normal hearing adult males and 15 females participated. N1-P2 components were evoked while listening to self-produced nonaltered and frequency shifted /a/ tokens and during production of /a/ tokens during nonaltered…

  5. Auditory Masking Effects on Speech Fluency in Apraxia of Speech and Aphasia: Comparison to Altered Auditory Feedback

    Science.gov (United States)

    Jacks, Adam; Haley, Katarina L.

    2015-01-01

    Purpose: To study the effects of masked auditory feedback (MAF) on speech fluency in adults with aphasia and/or apraxia of speech (APH/AOS). We hypothesized that adults with AOS would increase speech fluency when speaking with noise. Altered auditory feedback (AAF; i.e., delayed/frequency-shifted feedback) was included as a control condition not…

  6. Forebrain GABAergic projections to locus coeruleus in mouse.

    Science.gov (United States)

    Dimitrov, Eugene L; Yanagawa, Yuchio; Usdin, Ted B

    2013-07-01

    The noradrenergic locus coeruleus (LC) regulates arousal, memory, sympathetic nervous system activity, and pain. Forebrain projections to LC have been characterized in rat, cat, and primates, but not systematically in mouse. We surveyed mouse forebrain LC-projecting neurons by examining retrogradely labeled cells following LC iontophoresis of Fluoro-Gold and anterograde LC labeling after forebrain injection of biotinylated dextran amine or viral tracer. Similar to other species, the central amygdalar nucleus (CAmy), anterior hypothalamus, paraventricular nucleus, and posterior lateral hypothalamic area (PLH) provide major LC inputs. By using mice expressing green fluorescent protein in γ-aminobutyric acid (GABA)ergic neurons, we found that more than one-third of LC-projecting CAmy and PLH neurons are GABAergic. LC colocalization of biotinylated dextran amine, following CAmy or PLH injection, with either green fluorescent protein or glutamic acid decarboxylase (GAD)65/67 immunoreactivity confirmed these GABAergic projections. CAmy injection of adeno-associated virus encoding channelrhodopsin-2-Venus showed similar fiber labeling and association with GAD65/67-immunoreactive (ir) and tyrosine hydroxylase (TH)-ir neurons. CAmy and PLH projections were densest in a pericoerulear zone, but many fibers entered the LC proper. Close apposition between CAmy GABAergic projections and TH-ir processes suggests that CAmy GABAergic neurons may directly inhibit noradrenergic principal neurons. Direct LC neuron targeting was confirmed by anterograde transneuronal labeling of LC TH-ir neurons following CAmy or PLH injection of a herpes virus that expresses red fluorescent protein following activation by Cre recombinase in mice that express Cre recombinase in GABAergic neurons. This description of GABAergic projections from the CAmy and PLH to the LC clarifies important forebrain sources of inhibitory control of central nervous system noradrenergic activity.

  7. Forebrain activation in REM sleep: an FDG PET study.

    Science.gov (United States)

    Nofzinger, E A; Mintun, M A; Wiseman, M; Kupfer, D J; Moore, R Y

    1997-10-03

    Rapid eye movement (REM) sleep is a behavioral state characterized by cerebral cortical activation with dreaming as an associated behavior. The brainstem mechanisms involved in the generation of REM sleep are well-known, but the forebrain mechanisms that might distinguish it from waking are not well understood. We report here a positron emission tomography (PET) study of regional cerebral glucose utilization in the human forebrain during REM sleep in comparison to waking in six healthy adult females using the 18F-deoxyglucose method. In REM sleep, there is relative activation, shown by increased glucose utilization, in phylogenetically old limbic and paralimbic regions which include the lateral hypothalamic area, amygdaloid complex, septal-ventral striatal areas, and infralimbic, prelimbic, orbitofrontal, cingulate, entorhinal and insular cortices. The largest area of activation is a bilateral, confluent paramedian zone which extends from the septal area into ventral striatum, infralimbic, prelimbic, orbitofrontal and anterior cingulate cortex. There are only small and scattered areas of apparent deactivation. These data suggest that an important function of REM sleep is the integration of neocortical function with basal forebrain-hypothalamic motivational and reward mechanisms. This is in accordance with views that alterations in REM sleep in psychiatric disorders, such as depression, may reflect dysregulation in limbic and paralimbic structures.

  8. Are auditory percepts determined by experience?

    Science.gov (United States)

    Monson, Brian B; Han, Shui'Er; Purves, Dale

    2013-01-01

    Audition--what listeners hear--is generally studied in terms of the physical properties of sound stimuli and physiological properties of the auditory system. Based on recent work in vision, we here consider an alternative perspective that sensory percepts are based on past experience. In this framework, basic auditory qualities (e.g., loudness and pitch) are based on the frequency of occurrence of stimulus patterns in natural acoustic stimuli. To explore this concept of audition, we examined five well-documented psychophysical functions. The frequency of occurrence of acoustic patterns in a database of natural sound stimuli (speech) predicts some qualitative aspects of these functions, but with substantial quantitative discrepancies. This approach may offer a rationale for auditory phenomena that are difficult to explain in terms of the physical attributes of the stimuli as such.

  9. Are auditory percepts determined by experience?

    Directory of Open Access Journals (Sweden)

    Brian B Monson

    Full Text Available Audition--what listeners hear--is generally studied in terms of the physical properties of sound stimuli and physiological properties of the auditory system. Based on recent work in vision, we here consider an alternative perspective that sensory percepts are based on past experience. In this framework, basic auditory qualities (e.g., loudness and pitch are based on the frequency of occurrence of stimulus patterns in natural acoustic stimuli. To explore this concept of audition, we examined five well-documented psychophysical functions. The frequency of occurrence of acoustic patterns in a database of natural sound stimuli (speech predicts some qualitative aspects of these functions, but with substantial quantitative discrepancies. This approach may offer a rationale for auditory phenomena that are difficult to explain in terms of the physical attributes of the stimuli as such.

  10. Auditory processing in fragile x syndrome.

    Science.gov (United States)

    Rotschafer, Sarah E; Razak, Khaleel A

    2014-01-01

    Fragile X syndrome (FXS) is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral, and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle response is seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning, and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable, and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional, and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  11. Auditory Processing in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Sarah E Rotschafer

    2014-02-01

    Full Text Available Fragile X syndrome (FXS is an inherited form of intellectual disability and autism. Among other symptoms, FXS patients demonstrate abnormalities in sensory processing and communication. Clinical, behavioral and electrophysiological studies consistently show auditory hypersensitivity in humans with FXS. Consistent with observations in humans, the Fmr1 KO mouse model of FXS also shows evidence of altered auditory processing and communication deficiencies. A well-known and commonly used phenotype in pre-clinical studies of FXS is audiogenic seizures. In addition, increased acoustic startle is also seen in the Fmr1 KO mice. In vivo electrophysiological recordings indicate hyper-excitable responses, broader frequency tuning and abnormal spectrotemporal processing in primary auditory cortex of Fmr1 KO mice. Thus, auditory hyper-excitability is a robust, reliable and translatable biomarker in Fmr1 KO mice. Abnormal auditory evoked responses have been used as outcome measures to test therapeutics in FXS patients. Given that similarly abnormal responses are present in Fmr1 KO mice suggests that cellular mechanisms can be addressed. Sensory cortical deficits are relatively more tractable from a mechanistic perspective than more complex social behaviors that are typically studied in autism and FXS. The focus of this review is to bring together clinical, functional and structural studies in humans with electrophysiological and behavioral studies in mice to make the case that auditory hypersensitivity provides a unique opportunity to integrate molecular, cellular, circuit level studies with behavioral outcomes in the search for therapeutics for FXS and other autism spectrum disorders.

  12. Sensorimotor nucleus NIf is necessary for auditory processing but not vocal motor output in the avian song system.

    Science.gov (United States)

    Cardin, Jessica A; Raksin, Jonathan N; Schmidt, Marc F

    2005-04-01

    Sensorimotor integration in the avian song system is crucial for both learning and maintenance of song, a vocal motor behavior. Although a number of song system areas demonstrate both sensory and motor characteristics, their exact roles in auditory and premotor processing are unclear. In particular, it is unknown whether input from the forebrain nucleus interface of the nidopallium (NIf), which exhibits both sensory and premotor activity, is necessary for both auditory and premotor processing in its target, HVC. Here we show that bilateral NIf lesions result in long-term loss of HVC auditory activity but do not impair song production. NIf is thus a major source of auditory input to HVC, but an intact NIf is not necessary for motor output in adult zebra finches.

  13. Impact of Educational Level on Performance on Auditory Processing Tests.

    Science.gov (United States)

    Murphy, Cristina F B; Rabelo, Camila M; Silagi, Marcela L; Mansur, Letícia L; Schochat, Eliane

    2016-01-01

    Research has demonstrated that a higher level of education is associated with better performance on cognitive tests among middle-aged and elderly people. However, the effects of education on auditory processing skills have not yet been evaluated. Previous demonstrations of sensory-cognitive interactions in the aging process indicate the potential importance of this topic. Therefore, the primary purpose of this study was to investigate the performance of middle-aged and elderly people with different levels of formal education on auditory processing tests. A total of 177 adults with no evidence of cognitive, psychological or neurological conditions took part in the research. The participants completed a series of auditory assessments, including dichotic digit, frequency pattern and speech-in-noise tests. A working memory test was also performed to investigate the extent to which auditory processing and cognitive performance were associated. The results demonstrated positive but weak correlations between years of schooling and performance on all of the tests applied. The factor "years of schooling" was also one of the best predictors of frequency pattern and speech-in-noise test performance. Additionally, performance on the working memory, frequency pattern and dichotic digit tests was also correlated, suggesting that the influence of educational level on auditory processing performance might be associated with the cognitive demand of the auditory processing tests rather than auditory sensory aspects itself. Longitudinal research is required to investigate the causal relationship between educational level and auditory processing skills.

  14. Basal forebrain degeneration precedes and predicts the cortical spread of Alzheimer's pathology

    OpenAIRE

    Schmitz, Taylor W.; Nathan Spreng, R.; Weiner, Michael W.; Aisen, Paul; Petersen, Ronald; Jack, Clifford R; Jagust, William; Trojanowki, John Q.; Toga, Arthur W; Beckett, Laurel; Green, Robert C.; Saykin, Andrew J.; Morris, John; Leslie M Shaw; Khachaturian, Zaven

    2016-01-01

    There is considerable debate whether Alzheimer's disease (AD) originates in basal forebrain or entorhinal cortex. Here we examined whether longitudinal decreases in basal forebrain and entorhinal cortex grey matter volume were interdependent and sequential. In a large cohort of age-matched older adults ranging from cognitively normal to AD, we demonstrate that basal forebrain volume predicts longitudinal entorhinal degeneration. Models of parallel degeneration or entorhinal origin received ne...

  15. Auditory stream formation affects comodulation masking release retroactively

    DEFF Research Database (Denmark)

    Dau, Torsten; Ewert, Stephan; Oxenham, A. J.

    2009-01-01

    in terms of the sequence of "postcursor" flanking bands forming a perceptual stream with the original flanking bands, resulting in perceptual segregation of the flanking bands from the masker. The results are consistent with the idea that modulation analysis occurs within, not across, auditory objects......, and that across-frequency CMR only occurs if the on-frequency and flanking bands fall within the same auditory object or stream....

  16. Transient auditory hallucinations in an adolescent.

    Science.gov (United States)

    Skokauskas, Norbert; Pillay, Devina; Moran, Tom; Kahn, David A

    2010-05-01

    In adolescents, hallucinations can be a transient illness or can be associated with non-psychotic psychopathology, psychosocial adversity, or a physical illness. We present the case of a 15-year-old secondary-school student who presented with a 1-month history of first onset auditory hallucinations, which had been increasing in frequency and severity, and mild paranoid ideation. Over a 10-week period, there was a gradual diminution, followed by a complete resolution, of symptoms. We discuss issues regarding the diagnosis and prognosis of auditory hallucinations in adolescents.

  17. Effects of pre- and postnatal exposure to extremely low-frequency electric fields on mismatch negativity component of the auditory event-related potentials: Relation to oxidative stress.

    Science.gov (United States)

    Akpınar, Deniz; Gok, Deniz Kantar; Hidisoglu, Enis; Aslan, Mutay; Ozen, Sukru; Agar, Aysel; Yargicoglu, Piraye

    2016-01-01

    In our previous study, the developmental effects of extremely low-frequency electric fields (ELF-EF) on visual and somatosensory evoked potentials in adult rats were studied. There is no study so far examining the effects of 50 Hz electric field (EF) on mismatch negativity (MMN) recordings after exposure of rats during development. Therefore, our present study aimed to investigate MMN and oxidative brain damage in rats exposed to EF (12 kV/m, 1 h/day). Rats were divided into four groups, namely control (C), prenatal (Pr), postnatal (Po), and prenatal+postnatal (PP). Pregnant rats of Pr and PP groups were exposed to EF during pregnancy. Following birth, rats of PP and Po groups were exposed to EF for three months. After exposure to EF, MMN was recorded by electrodes positioned stereotaxically to the surface of the dura, and then brain tissues were removed for histological and biochemical analyses. The MMN amplitude was higher to deviant tones than to standard tones. It was decreased in all experimental groups compared with the C group. 4-Hydroxy-2-nonenal (4-HNE) levels were significantly increased in the Po group with respect to the C group, whereas they were significantly decreased in the PP group compared with Pr and Po groups. Protein carbonyl levels were significantly decreased in the PP group compared with C, Pr, and Po groups. EF decreased MMN amplitudes were possibly induced by lipid peroxidation.

  18. Weak responses to auditory feedback perturbation during articulation in persons who stutter: evidence for abnormal auditory-motor transformation.

    Directory of Open Access Journals (Sweden)

    Shanqing Cai

    Full Text Available Previous empirical observations have led researchers to propose that auditory feedback (the auditory perception of self-produced sounds when speaking functions abnormally in the speech motor systems of persons who stutter (PWS. Researchers have theorized that an important neural basis of stuttering is the aberrant integration of auditory information into incipient speech motor commands. Because of the circumstantial support for these hypotheses and the differences and contradictions between them, there is a need for carefully designed experiments that directly examine auditory-motor integration during speech production in PWS. In the current study, we used real-time manipulation of auditory feedback to directly investigate whether the speech motor system of PWS utilizes auditory feedback abnormally during articulation and to characterize potential deficits of this auditory-motor integration. Twenty-one PWS and 18 fluent control participants were recruited. Using a short-latency formant-perturbation system, we examined participants' compensatory responses to unanticipated perturbation of auditory feedback of the first formant frequency during the production of the monophthong [ε]. The PWS showed compensatory responses that were qualitatively similar to the controls' and had close-to-normal latencies (∼150 ms, but the magnitudes of their responses were substantially and significantly smaller than those of the control participants (by 47% on average, p<0.05. Measurements of auditory acuity indicate that the weaker-than-normal compensatory responses in PWS were not attributable to a deficit in low-level auditory processing. These findings are consistent with the hypothesis that stuttering is associated with functional defects in the inverse models responsible for the transformation from the domain of auditory targets and auditory error information into the domain of speech motor commands.

  19. Visualization of the medial forebrain bundle using diffusion tensor imaging

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    Ardian eHana

    2015-10-01

    Full Text Available Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were 6 women and 9 men. The mean age was 58,6 years (39-77. Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson`s disease and one had multiple sclerosis. The remaining 6 patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 x 200 mm², slice thickness 2 mm, and an acquisition matrix of 96 x 96 yielding nearly isotropic voxels of 2 x 2 x 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm². The maximal angle was 50°. Additional scanning time was less than 9 minutes. We were able to visualize the medial forebrain bundle in 12 of our patients bilaterally and in the remaining 3 patients we depicted the medial forebrain bundle on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the medial forebrain bundle is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Furthermore it might explain at a certain extent character changes in patients with lesions in the frontal lobe. Surgery in this part of the brain should always take the preservation of this white matter tract into account.

  20. Basal Forebrain Cholinergic System and Orexin Neurons: Effects on Attention

    Science.gov (United States)

    Villano, Ines; Messina, Antonietta; Valenzano, Anna; Moscatelli, Fiorenzo; Esposito, Teresa; Monda, Vincenzo; Esposito, Maria; Precenzano, Francesco; Carotenuto, Marco; Viggiano, Andrea; Chieffi, Sergio; Cibelli, Giuseppe; Monda, Marcellino; Messina, Giovanni

    2017-01-01

    The basal forebrain (BF) cholinergic system has an important role in attentive functions. The cholinergic system can be activated by different inputs, and in particular, by orexin neurons, whose cell bodies are located within the postero-lateral hypothalamus. Recently the orexin-producing neurons have been proved to promote arousal and attention through their projections to the BF. The aim of this review article is to summarize the evidence showing that the orexin system contributes to attentional processing by an increase in cortical acetylcholine release and in cortical neurons activity. PMID:28197081

  1. Auditory Integration Training

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2002-07-01

    Full Text Available Auditory integration training (AIT is a hearing enhancement training process for sensory input anomalies found in individuals with autism, attention deficit hyperactive disorder, dyslexia, hyperactivity, learning disability, language impairments, pervasive developmental disorder, central auditory processing disorder, attention deficit disorder, depressin, and hyperacute hearing. AIT, recently introduced in the United States, and has received much notice of late following the release of The Sound of a Moracle, by Annabel Stehli. In her book, Mrs. Stehli describes before and after auditory integration training experiences with her daughter, who was diagnosed at age four as having autism.

  2. Rabbit Forebrain cholinergic system : Morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus

    NARCIS (Netherlands)

    Varga, C; Hartig, W; Grosche, J; Luiten, PGM; Seeger, J; Brauer, K; Harkany, T; Härtig, Wolfgang; Keijser, Jan N.

    2003-01-01

    Although the rabbit brain, in particular the basal forebrain cholinergic system, has become a common model for neuropathological changes associated with Alzheimer's disease, detailed neuroanatomical studies on the morphological organization of basal forebrain cholinergic nuclei and on their output p

  3. Comparison of Electrophysiological Auditory Measures in Fishes.

    Science.gov (United States)

    Maruska, Karen P; Sisneros, Joseph A

    2016-01-01

    Sounds provide fishes with important information used to mediate behaviors such as predator avoidance, prey detection, and social communication. How we measure auditory capabilities in fishes, therefore, has crucial implications for interpreting how individual species use acoustic information in their natural habitat. Recent analyses have highlighted differences between behavioral and electrophysiologically determined hearing thresholds, but less is known about how physiological measures at different auditory processing levels compare within a single species. Here we provide one of the first comparisons of auditory threshold curves determined by different recording methods in a single fish species, the soniferous Hawaiian sergeant fish Abudefduf abdominalis, and review past studies on representative fish species with tuning curves determined by different methods. The Hawaiian sergeant is a colonial benthic-spawning damselfish (Pomacentridae) that produces low-frequency, low-intensity sounds associated with reproductive and agonistic behaviors. We compared saccular potentials, auditory evoked potentials (AEP), and single neuron recordings from acoustic nuclei of the hindbrain and midbrain torus semicircularis. We found that hearing thresholds were lowest at low frequencies (~75-300 Hz) for all methods, which matches the spectral components of sounds produced by this species. However, thresholds at best frequency determined via single cell recordings were ~15-25 dB lower than those measured by AEP and saccular potential techniques. While none of these physiological techniques gives us a true measure of the auditory "perceptual" abilities of a naturally behaving fish, this study highlights that different methodologies can reveal similar detectable range of frequencies for a given species, but absolute hearing sensitivity may vary considerably.

  4. Effects of sequential streaming on auditory masking using psychoacoustics and auditory evoked potentials.

    Science.gov (United States)

    Verhey, Jesko L; Ernst, Stephan M A; Yasin, Ifat

    2012-03-01

    The present study was aimed at investigating the relationship between the mismatch negativity (MMN) and psychoacoustical effects of sequential streaming on comodulation masking release (CMR). The influence of sequential streaming on CMR was investigated using a psychoacoustical alternative forced-choice procedure and electroencephalography (EEG) for the same group of subjects. The psychoacoustical data showed, that adding precursors comprising of only off-signal-frequency maskers abolished the CMR. Complementary EEG data showed an MMN irrespective of the masker envelope correlation across frequency when only the off-signal-frequency masker components were present. The addition of such precursors promotes a separation of the on- and off-frequency masker components into distinct auditory objects preventing the auditory system from using comodulation as an additional cue. A frequency-specific adaptation changing the representation of the flanking bands in the streaming conditions may also contribute to the reduction of CMR in the stream conditions, however, it is unlikely that adaptation is the primary reason for the streaming effect. A neurophysiological correlate of sequential streaming was found in EEG data using MMN, but the magnitude of the MMN was not correlated with the audibility of the signal in CMR experiments. Dipole source analysis indicated different cortical regions involved in processing auditory streaming and modulation detection. In particular, neural sources for processing auditory streaming include cortical regions involved in decision-making.

  5. Demonstration of muscarinic acetylcholine receptor-like immunoreactivity in the rat forebrain and upper brainstem

    NARCIS (Netherlands)

    Zee, E.A. van der; Matsuyama, T.; Strosberg, A.D.; Traber, J.; Luiten, P.G.M.

    1989-01-01

    The distribution of muscarinic acetylcholine receptor protein (mAChR) in the rat forebrain and upper brainstem was described by using a monoclonal antibody (M35) raised against mAChR purified from bovine forebrain homogenates. A method is investigated for light microscopic (LM) and electronmicroscop

  6. Auditory Responses of Infants

    Science.gov (United States)

    Watrous, Betty Springer; And Others

    1975-01-01

    Forty infants, 3- to 12-months-old, participated in a study designed to differentiate the auditory response characteristics of normally developing infants in the age ranges 3 - 5 months, 6 - 8 months, and 9 - 12 months. (Author)

  7. Learning and the motivation to eat: forebrain circuitry.

    Science.gov (United States)

    Petrovich, Gorica D

    2011-09-26

    Appetite and eating are not only controlled by energy needs, but also by extrinsic factors that are not directly related to energy balance. Environmental signals that acquire motivational properties through associative learning-learned cues-can override homeostatic signals and stimulate eating in sated states, or inhibit eating in states of hunger. Such influences are important, as environmental factors are believed to contribute to the increased susceptibility to overeating and the rise in obesity in the developed world. Similarly, environmental and social factors contribute to the onset and maintenance of anorexia nervosa and other eating disorders through interactions with the individual genetic background. Nevertheless, how learning enables environmental signals to control feeding, and the underlying brain mechanisms are poorly understood. We developed two rodent models to study how learned cues are integrated with homeostatic signals within functional forebrain networks, and how these networks are modulated by experience. In one model, a cue previously paired with food when an animal was hungry induces eating in sated rats. In the other model, food-deprived rats inhibit feeding when presented with a cue that signals danger, a tone previously paired with footshocks. Here evidence will be reviewed that the forebrain network formed by the amygdala, lateral hypothalamus and medial prefrontal cortex mediates cue-driven feeding, while a parallel amygdalar circuitry mediates suppression of eating by the fear cue. Findings from the animal models may be relevant for understanding aspects of human appetite and eating, and maladaptive mechanisms that could lead to overeating and anorexia.

  8. Behavioral performance of rats following transient forebrain ischemia.

    Science.gov (United States)

    Volpe, B T; Pulsinelli, W A; Tribuna, J; Davis, H P

    1984-01-01

    Rats subjected to transient forebrain ischemic injury by the method of four vessel occlusion (4-VO) develop irreversible injury to select populations of vulnerable neurons which include pyramidal cells in the CA-1 region of the hippocampus. This brain area is thought to be crucial for learning and memory. Rats subjected to 30 minutes of 4-VO, and then cerebral reperfusion were tested on a radial 8-arm maze task after they had recovered. The data shows that both 4-VO and control animals improve their performance over trials, but that 4-VO rats are impaired on "working" and "reference" tasks. The data suggest that 4-VO rats' impaired "working" performance is permanent, compared to their transient "reference" impairment. Alterations in sensorimotor activity could not account for these performance deficits since control and 4-VO rats demonstrated equivalent choice time per maze arm. Performance deficits in rats following forebrain ischemic injury may be similar to some of the cognitive deficits found in humans survivors of cerebral hypoxia-ischemia.

  9. Dcc regulates asymmetric outgrowth of forebrain neurons in zebrafish.

    Directory of Open Access Journals (Sweden)

    Jingxia Gao

    Full Text Available The guidance receptor DCC (deleted in colorectal cancer ortholog UNC-40 regulates neuronal asymmetry development in Caenorhabditis elegans, but it is not known whether DCC plays a role in the specification of neuronal polarity in vertebrates. To examine the roles of DCC in neuronal asymmetry regulation in vertebrates, we studied zebrafish anterior dorsal telencephalon (ADt neuronal axons. We generated transgenic zebrafish animals expressing the photo-convertible fluorescent protein Kaede in ADt neurons and then photo-converted Kaede to label specifically the ADt neuron axons. We found that ADt axons normally project ventrally. Knock down of Dcc function by injecting antisense morpholino oligonucleotides caused the ADt neurons to project axons dorsally. To examine the axon projection pattern of individual ADt neurons, we labeled single ADt neurons using a forebrain-specific promoter to drive fluorescent protein expression. We found that individual ADt neurons projected axons dorsally or formed multiple processes after morpholino knock down of Dcc function. We further found that knock down of the Dcc ligand, Netrin1, also caused ADt neurons to project axons dorsally. Knockdown of Neogenin1, a guidance receptor closely related to Dcc, enhanced the formation of aberrant dorsal axons in embryos injected with Dcc morpholino. These experiments provide the first evidence that Dcc regulates polarized axon initiation and asymmetric outgrowth of forebrain neurons in vertebrates.

  10. Formal auditory training in adult hearing aid users

    Directory of Open Access Journals (Sweden)

    Daniela Gil

    2010-01-01

    Full Text Available INTRODUCTION: Individuals with sensorineural hearing loss are often able to regain some lost auditory function with the help of hearing aids. However, hearing aids are not able to overcome auditory distortions such as impaired frequency resolution and speech understanding in noisy environments. The coexistence of peripheral hearing loss and a central auditory deficit may contribute to patient dissatisfaction with amplification, even when audiological tests indicate nearly normal hearing thresholds. OBJECTIVE: This study was designed to validate the effects of a formal auditory training program in adult hearing aid users with mild to moderate sensorineural hearing loss. METHODS: Fourteen bilateral hearing aid users were divided into two groups: seven who received auditory training and seven who did not. The training program was designed to improve auditory closure, figure-to-ground for verbal and nonverbal sounds and temporal processing (frequency and duration of sounds. Pre- and post-training evaluations included measuring electrophysiological and behavioral auditory processing and administration of the Abbreviated Profile of Hearing Aid Benefit (APHAB self-report scale. RESULTS: The post-training evaluation of the experimental group demonstrated a statistically significant reduction in P3 latency, improved performance in some of the behavioral auditory processing tests and higher hearing aid benefit in noisy situations (p-value < 0,05. No changes were noted for the control group (p-value <0,05. CONCLUSION: The results demonstrated that auditory training in adult hearing aid users can lead to a reduction in P3 latency, improvements in sound localization, memory for nonverbal sounds in sequence, auditory closure, figure-to-ground for verbal sounds and greater benefits in reverberant and noisy environments.

  11. Increased BOLD Signals Elicited by High Gamma Auditory Stimulation of the Left Auditory Cortex in Acute State Schizophrenia

    Directory of Open Access Journals (Sweden)

    Hironori Kuga, M.D.

    2016-10-01

    We acquired BOLD responses elicited by click trains of 20, 30, 40 and 80-Hz frequencies from 15 patients with acute episode schizophrenia (AESZ, 14 symptom-severity-matched patients with non-acute episode schizophrenia (NASZ, and 24 healthy controls (HC, assessed via a standard general linear-model-based analysis. The AESZ group showed significantly increased ASSR-BOLD signals to 80-Hz stimuli in the left auditory cortex compared with the HC and NASZ groups. In addition, enhanced 80-Hz ASSR-BOLD signals were associated with more severe auditory hallucination experiences in AESZ participants. The present results indicate that neural over activation occurs during 80-Hz auditory stimulation of the left auditory cortex in individuals with acute state schizophrenia. Given the possible association between abnormal gamma activity and increased glutamate levels, our data may reflect glutamate toxicity in the auditory cortex in the acute state of schizophrenia, which might lead to progressive changes in the left transverse temporal gyrus.

  12. Tuning up the developing auditory CNS.

    Science.gov (United States)

    Sanes, Dan H; Bao, Shaowen

    2009-04-01

    Although the auditory system has limited information processing resources, the acoustic environment is infinitely variable. To properly encode the natural environment, the developing central auditory system becomes somewhat specialized through experience-dependent adaptive mechanisms that operate during a sensitive time window. Recent studies have demonstrated that cellular and synaptic plasticity occurs throughout the central auditory pathway. Acoustic-rearing experiments can lead to an over-representation of the exposed sound frequency, and this is associated with specific changes in frequency discrimination. These forms of cellular plasticity are manifest in brain regions, such as midbrain and cortex, which interact through feed-forward and feedback pathways. Hearing loss leads to a profound re-weighting of excitatory and inhibitory synaptic gain throughout the auditory CNS, and this is associated with an over-excitability that is observed in vivo. Further behavioral and computational analyses may provide insights into how theses cellular and systems plasticity effects underlie the development of cognitive functions such as speech perception.

  13. [Analysis of auditory information in the brain of the cetacean].

    Science.gov (United States)

    Popov, V V; Supin, A Ia

    2006-01-01

    The cetacean brain specifics involve an exceptional development of the auditory neural centres. The place of projection sensory areas including the auditory that in the cetacean brain cortex is essentially different from that in other mammals. The EP characteristics indicated presence of several functional divisions in the auditory cortex. Physiological studies of the cetacean auditory centres were mainly performed using the EP technique. Of several types of the EPs, the short-latency auditory EP was most thoroughly studied. In cetacean, it is characterised by exceptionally high temporal resolution with the integration time about 0.3 ms which corresponds to the cut-off frequency 1700 Hz. This much exceeds the temporal resolution of the hearing in terranstrial mammals. The frequency selectivity of hearing in cetacean was measured using a number of variants of the masking technique. The hearing frequency selectivity acuity in cetacean exceeds that of most terraneous mammals (excepting the bats). This acute frequency selectivity provides the differentiation among the finest spectral patterns of auditory signals.

  14. Substitution of natural sensory input by artificial neurostimulation of an amputated trigeminal nerve does not prevent the degeneration of basal forebrain cholinergic circuits projecting to the somatosensory cortex

    Directory of Open Access Journals (Sweden)

    Celia eHerrera-Rincon

    2014-11-01

    Full Text Available Peripheral deafferentation downregulates acetylcholine (ACh synthesis in sensory cortices. However the responsible neural circuits and processes are not known. We irreversibly transected the rat infraorbital nerve and implanted neuroprosthetic microdevices for proximal stump stimulation, and assessed cytochrome-oxidase and choline- acetyl-transferase (ChAT in somatosensory, auditory and visual cortices; estimated the number and density of ACh-neurons in the magnocellular basal nucleus (MBN; and localized down-regulated ACh-neurons in basal forebrain using retrograde labeling from deafferented cortices. Here we show that nerve transection, causes down regulation of MBN cholinergic neurons. Stimulation of the cut nerve reverses the metabolic decline but does not affect the decrease in cholinergic fibers in cortex or cholinergic neurons in basal forebrain. Artifical stimulation of the nerve also has no affect of ACh-innervation of other cortices. Cortical ChAT depletion is due to loss of corticopetal MBN ChAT-expressing neurons. MBN ChAT downregulation is not due to decrease neither of afferent activity nor to failure of trophic support. Basalocortical ACh circuits are sensory specific, ACh is provided to each sensory cortex on demand by dedicated circuits. Our data support the existence of a modality-specific cortex-MBN-cortex circuit for cognitive information processing.

  15. Autosomal recessive hereditary auditory neuropathy

    Institute of Scientific and Technical Information of China (English)

    王秋菊; 顾瑞; 曹菊阳

    2003-01-01

    evidence of peripheral neuropathy at the time of this writing. Conclusions: In this study, patients with feature of non- syndromic hereditary auditory neuropathy were identified in three Chinese families.Pedigree analysis indicates autosomal recessive inheritances in the pedigrees. The observed inheritance and clinical audiologic findings are different from those previously described for non-syndromic low-frequency sensorineural hearing loss. This information should facilitate future molecular candidate genes screening for understanding the mechanism of AN.

  16. Expressional changes in cerebrovascular receptors after experimental transient forebrain ischemia

    DEFF Research Database (Denmark)

    Johansson, Sara; Povlsen, Gro Klitgaard; Edvinsson, Lars

    2012-01-01

    of vasoconstrictive endothelin and 5-hydroxytryptamine receptors in cerebral arteries. Experimental transient forebrain ischemia of varying durations was induced in male wistar rats, followed by reperfusion for 48 hours. Neurological function was assessed daily by three different tests and cerebrovascular expression......Global ischemic stroke is one of the most prominent consequences of cardiac arrest, since the diminished blood flow to the brain results in cell damage and sometimes permanently impaired neurological function. The post-arrest period is often characterised by cerebral hypoperfusion due to subacute...... the insult, a phenomenon that leads to increased contraction of cerebral arteries, reduced perfusion of the affected area and worsened ischemic damage. Based on these findings, the aim of the present study was to investigate if transient global cerebral ischemia is associated with upregulation...

  17. Efficient in vivo electroporation of the postnatal rodent forebrain.

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    Camille Boutin

    Full Text Available Functional gene analysis in vivo represents still a major challenge in biomedical research. Here we present a new method for the efficient introduction of nucleic acids into the postnatal mouse forebrain. We show that intraventricular injection of DNA followed by electroporation induces strong expression of transgenes in radial glia, neuronal precursors and neurons of the olfactory system. We present two proof-of-principle experiments to validate our approach. First, we show that expression of a human isoform of the neural cell adhesion molecule (hNCAM-140 in radial glia cells induces their differentiation into cells showing a neural precursor phenotype. Second, we demonstrate that p21 acts as a cell cycle inhibitor for postnatal neural stem cells. This approach will represent an important tool for future studies of postnatal neurogenesis and of neural development in general.

  18. Dynamic behaviour of human neuroepithelial cells in the developing forebrain

    Science.gov (United States)

    Subramanian, Lakshmi; Bershteyn, Marina; Paredes, Mercedes F.; Kriegstein, Arnold R.

    2017-01-01

    To understand how diverse progenitor cells contribute to human neocortex development, we examined forebrain progenitor behaviour using timelapse imaging. Here we find that cell cycle dynamics of human neuroepithelial (NE) cells differ from radial glial (RG) cells in both primary tissue and in stem cell-derived organoids. NE cells undergoing proliferative, symmetric divisions retract their basal processes, and both daughter cells regrow a new process following cytokinesis. The mitotic retraction of the basal process is recapitulated by NE cells in cerebral organoids generated from human-induced pluripotent stem cells. In contrast, RG cells undergoing vertical cleavage retain their basal fibres throughout mitosis, both in primary tissue and in older organoids. Our findings highlight developmentally regulated changes in mitotic behaviour that may relate to the role of RG cells to provide a stable scaffold for neuronal migration, and suggest that the transition in mitotic dynamics can be studied in organoid models. PMID:28139695

  19. Song competition affects monoamine levels in sensory and motor forebrain regions of male Lincoln's sparrows (Melospiza lincolnii.

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    Kendra B Sewall

    Full Text Available Male animals often change their behavior in response to the level of competition for mates. Male Lincoln's sparrows (Melospiza lincolnii modulate their competitive singing over the period of a week as a function of the level of challenge associated with competitors' songs. Differences in song challenge and associated shifts in competitive state should be accompanied by neural changes, potentially in regions that regulate perception and song production. The monoamines mediate neural plasticity in response to environmental cues to achieve shifts in behavioral state. Therefore, using high pressure liquid chromatography with electrochemical detection, we compared levels of monoamines and their metabolites from male Lincoln's sparrows exposed to songs categorized as more or less challenging. We compared levels of norepinephrine and its principal metabolite in two perceptual regions of the auditory telencephalon, the caudomedial nidopallium and the caudomedial mesopallium (CMM, because this chemical is implicated in modulating auditory sensitivity to song. We also measured the levels of dopamine and its principal metabolite in two song control nuclei, area X and the robust nucleus of the arcopallium (RA, because dopamine is implicated in regulating song output. We measured the levels of serotonin and its principal metabolite in all four brain regions because this monoamine is implicated in perception and behavioral output and is found throughout the avian forebrain. After controlling for recent singing, we found that males exposed to more challenging song had higher levels of norepinephrine metabolite in the CMM and lower levels of serotonin in the RA. Collectively, these findings are consistent with norepinephrine in perceptual brain regions and serotonin in song control regions contributing to neuroplasticity that underlies socially-induced changes in behavioral state.

  20. Song competition affects monoamine levels in sensory and motor forebrain regions of male Lincoln's sparrows (Melospiza lincolnii).

    Science.gov (United States)

    Sewall, Kendra B; Caro, Samuel P; Sockman, Keith W

    2013-01-01

    Male animals often change their behavior in response to the level of competition for mates. Male Lincoln's sparrows (Melospiza lincolnii) modulate their competitive singing over the period of a week as a function of the level of challenge associated with competitors' songs. Differences in song challenge and associated shifts in competitive state should be accompanied by neural changes, potentially in regions that regulate perception and song production. The monoamines mediate neural plasticity in response to environmental cues to achieve shifts in behavioral state. Therefore, using high pressure liquid chromatography with electrochemical detection, we compared levels of monoamines and their metabolites from male Lincoln's sparrows exposed to songs categorized as more or less challenging. We compared levels of norepinephrine and its principal metabolite in two perceptual regions of the auditory telencephalon, the caudomedial nidopallium and the caudomedial mesopallium (CMM), because this chemical is implicated in modulating auditory sensitivity to song. We also measured the levels of dopamine and its principal metabolite in two song control nuclei, area X and the robust nucleus of the arcopallium (RA), because dopamine is implicated in regulating song output. We measured the levels of serotonin and its principal metabolite in all four brain regions because this monoamine is implicated in perception and behavioral output and is found throughout the avian forebrain. After controlling for recent singing, we found that males exposed to more challenging song had higher levels of norepinephrine metabolite in the CMM and lower levels of serotonin in the RA. Collectively, these findings are consistent with norepinephrine in perceptual brain regions and serotonin in song control regions contributing to neuroplasticity that underlies socially-induced changes in behavioral state.

  1. Auditory and Visual Sensations

    CERN Document Server

    Ando, Yoichi

    2010-01-01

    Professor Yoichi Ando, acoustic architectural designer of the Kirishima International Concert Hall in Japan, presents a comprehensive rational-scientific approach to designing performance spaces. His theory is based on systematic psychoacoustical observations of spatial hearing and listener preferences, whose neuronal correlates are observed in the neurophysiology of the human brain. A correlation-based model of neuronal signal processing in the central auditory system is proposed in which temporal sensations (pitch, timbre, loudness, duration) are represented by an internal autocorrelation representation, and spatial sensations (sound location, size, diffuseness related to envelopment) are represented by an internal interaural crosscorrelation function. Together these two internal central auditory representations account for the basic auditory qualities that are relevant for listening to music and speech in indoor performance spaces. Observed psychological and neurophysiological commonalities between auditor...

  2. Continuity of visual and auditory rhythms influences sensorimotor coordination.

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    Manuel Varlet

    Full Text Available People often coordinate their movement with visual and auditory environmental rhythms. Previous research showed better performances when coordinating with auditory compared to visual stimuli, and with bimodal compared to unimodal stimuli. However, these results have been demonstrated with discrete rhythms and it is possible that such effects depend on the continuity of the stimulus rhythms (i.e., whether they are discrete or continuous. The aim of the current study was to investigate the influence of the continuity of visual and auditory rhythms on sensorimotor coordination. We examined the dynamics of synchronized oscillations of a wrist pendulum with auditory and visual rhythms at different frequencies, which were either unimodal or bimodal and discrete or continuous. Specifically, the stimuli used were a light flash, a fading light, a short tone and a frequency-modulated tone. The results demonstrate that the continuity of the stimulus rhythms strongly influences visual and auditory motor coordination. Participants' movement led continuous stimuli and followed discrete stimuli. Asymmetries between the half-cycles of the movement in term of duration and nonlinearity of the trajectory occurred with slower discrete rhythms. Furthermore, the results show that the differences of performance between visual and auditory modalities depend on the continuity of the stimulus rhythms as indicated by movements closer to the instructed coordination for the auditory modality when coordinating with discrete stimuli. The results also indicate that visual and auditory rhythms are integrated together in order to better coordinate irrespective of their continuity, as indicated by less variable coordination closer to the instructed pattern. Generally, the findings have important implications for understanding how we coordinate our movements with visual and auditory environmental rhythms in everyday life.

  3. Development of auditory localization accuracy and auditory spatial discrimination in children and adolescents.

    Science.gov (United States)

    Kühnle, S; Ludwig, A A; Meuret, S; Küttner, C; Witte, C; Scholbach, J; Fuchs, M; Rübsamen, R

    2013-01-01

    The present study investigated the development of two parameters of spatial acoustic perception in children and adolescents with normal hearing, aged 6-18 years. Auditory localization accuracy was quantified by means of a sound source identification task and auditory spatial discrimination acuity by measuring minimum audible angles (MAA). Both low- and high-frequency noise bursts were employed in the tests, thereby separately addressing auditory processing based on interaural time and intensity differences. Setup consisted of 47 loudspeakers mounted in the frontal azimuthal hemifield, ranging from 90° left to 90° right (-90°, +90°). Target signals were presented from 8 loudspeaker positions in the left and right hemifields (±4°, ±30°, ±60° and ±90°). Localization accuracy and spatial discrimination acuity showed different developmental courses. Localization accuracy remained stable from the age of 6 onwards. In contrast, MAA thresholds and interindividual variability of spatial discrimination decreased significantly with increasing age. Across all age groups, localization was most accurate and MAA thresholds were lower for frontal than for lateral sound sources, and for low-frequency compared to high-frequency noise bursts. The study also shows better performance in spatial hearing based on interaural time differences rather than on intensity differences throughout development. These findings confirm that specific aspects of central auditory processing show continuous development during childhood up to adolescence.

  4. Modulation of Specific Sensory Cortical Areas by Segregated Basal Forebrain Cholinergic Neurons Demonstrated by Neuronal Tracing and Optogenetic Stimulation in Mice

    Science.gov (United States)

    Chaves-Coira, Irene; Barros-Zulaica, Natali; Rodrigo-Angulo, Margarita; Núñez, Ángel

    2016-01-01

    Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF) projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-Gold (FlGo) and Fast Blue (FB) fluorescent retrograde tracers were deposited into the primary somatosensory (S1) and primary auditory (A1) cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB) projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B) nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP) under the control of the choline-acetyl transferase promoter (ChAT). Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  5. Modulation of specific sensory cortical areas by segregated basal forebrain cholinergic neurons demonstrated by neuronal tracing and optogenetic stimulation in mice

    Directory of Open Access Journals (Sweden)

    Irene eChaves-Coira

    2016-04-01

    Full Text Available Neocortical cholinergic activity plays a fundamental role in sensory processing and cognitive functions. Previous results have suggested a refined anatomical and functional topographical organization of basal forebrain (BF projections that may control cortical sensory processing in a specific manner. We have used retrograde anatomical procedures to demonstrate the existence of specific neuronal groups in the BF involved in the control of specific sensory cortices. Fluoro-gold and Fast Blue fluorescent retrograde tracers were deposited into the primary somatosensory (S1 and primary auditory (A1 cortices in mice. Our results revealed that the BF is a heterogeneous area in which neurons projecting to different cortical areas are segregated into different neuronal groups. Most of the neurons located in the horizontal limb of the diagonal band of Broca (HDB projected to the S1 cortex, indicating that this area is specialized in the sensory processing of tactile stimuli. However, the nucleus basalis magnocellularis (B nucleus shows a similar number of cells projecting to the S1 as to the A1 cortices. In addition, we analyzed the cholinergic effects on the S1 and A1 cortical sensory responses by optogenetic stimulation of the BF neurons in urethane-anesthetized transgenic mice. We used transgenic mice expressing the light-activated cation channel, channelrhodopsin-2, tagged with a fluorescent protein (ChR2-YFP under the control of the choline-acetyl transferase promoter (ChAT. Cortical evoked potentials were induced by whisker deflections or by auditory clicks. According to the anatomical results, optogenetic HDB stimulation induced more extensive facilitation of tactile evoked potentials in S1 than auditory evoked potentials in A1, while optogenetic stimulation of the B nucleus facilitated either tactile or auditory evoked potentials equally. Consequently, our results suggest that cholinergic projections to the cortex are organized into segregated

  6. Adenosine Inhibits the Excitatory Synaptic Inputs to Basal Forebrain Cholinergic, GABAergic and Parvalbumin Neurons in mice

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    Chun eYang

    2013-06-01

    Full Text Available Coffee and tea contain the stimulants caffeine and theophylline. These compounds act as antagonists of adenosine receptors. Adenosine promotes sleep and its extracellular concentration rises in association with prolonged wakefulness, particularly in the basal forebrain (BF region involved in activating the cerebral cortex. However, the effect of adenosine on identified BF neurons, especially non-cholinergic neurons, is incompletely understood. Here we used whole-cell patch-clamp recordings in mouse brain slices prepared from two validated transgenic mouse lines with fluorescent proteins expressed in GABAergic or parvalbumin (PV neurons to determine the effect of adenosine. Whole-cell recordings were made BF cholinergic neurons and from BF GABAergic & PV neurons with the size (>20 µm and intrinsic membrane properties (prominent H-currents corresponding to cortically projecting neurons. A brief (2 min bath application of adenosine (100 μM decreased the frequency but not the amplitude of spontaneous excitatory postsynaptic currents in all groups of BF cholinergic, GABAergic and PV neurons we recorded. In addition, adenosine decreased the frequency of miniature EPSCs in BF cholinergic neurons. Adenosine had no effect on the frequency of spontaneous inhibitory postsynaptic currents in cholinergic neurons or GABAergic neurons with large H-currents but reduced them in a group of GABAergic neurons with smaller H-currents. All effects of adenosine were blocked by a selective, adenosine A1 receptor antagonist, cyclopentyltheophylline (CPT, 1 μM. Adenosine had no postsynaptic effects. Taken together, our work suggests that adenosine promotes sleep by an A1-receptor mediated inhibition of glutamatergic inputs to cortically-projecting cholinergic and GABA/PV neurons. Conversely, caffeine and theophylline promote attentive wakefulness by inhibiting these A1 receptors in BF thereby promoting the high-frequency oscillations in the cortex required for

  7. Neurodynamics, tonality, and the auditory brainstem response.

    Science.gov (United States)

    Large, Edward W; Almonte, Felix V

    2012-04-01

    Tonal relationships are foundational in music, providing the basis upon which musical structures, such as melodies, are constructed and perceived. A recent dynamic theory of musical tonality predicts that networks of auditory neurons resonate nonlinearly to musical stimuli. Nonlinear resonance leads to stability and attraction relationships among neural frequencies, and these neural dynamics give rise to the perception of relationships among tones that we collectively refer to as tonal cognition. Because this model describes the dynamics of neural populations, it makes specific predictions about human auditory neurophysiology. Here, we show how predictions about the auditory brainstem response (ABR) are derived from the model. To illustrate, we derive a prediction about population responses to musical intervals that has been observed in the human brainstem. Our modeled ABR shows qualitative agreement with important features of the human ABR. This provides a source of evidence that fundamental principles of auditory neurodynamics might underlie the perception of tonal relationships, and forces reevaluation of the role of learning and enculturation in tonal cognition.

  8. Catecholaminergic innervation of central and peripheral auditory circuitry varies with reproductive state in female midshipman fish, Porichthys notatus.

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    Paul M Forlano

    Full Text Available In seasonal breeding vertebrates, hormone regulation of catecholamines, which include dopamine and noradrenaline, may function, in part, to modulate behavioral responses to conspecific vocalizations. However, natural seasonal changes in catecholamine innervation of auditory nuclei is largely unexplored, especially in the peripheral auditory system, where encoding of social acoustic stimuli is initiated. The plainfin midshipman fish, Porichthys notatus, has proven to be an excellent model to explore mechanisms underlying seasonal peripheral auditory plasticity related to reproductive social behavior. Recently, we demonstrated robust catecholaminergic (CA innervation throughout the auditory system in midshipman. Most notably, dopaminergic neurons in the diencephalon have widespread projections to auditory circuitry including direct innervation of the saccule, the main endorgan of hearing, and the cholinergic octavolateralis efferent nucleus (OE which also projects to the inner ear. Here, we tested the hypothesis that gravid, reproductive summer females show differential CA innervation of the auditory system compared to non-reproductive winter females. We utilized quantitative immunofluorescence to measure tyrosine hydroxylase immunoreactive (TH-ir fiber density throughout central auditory nuclei and the sensory epithelium of the saccule. Reproductive females exhibited greater density of TH-ir innervation in two forebrain areas including the auditory thalamus and greater density of TH-ir on somata and dendrites of the OE. In contrast, non-reproductive females had greater numbers of TH-ir terminals in the saccule and greater TH-ir fiber density in a region of the auditory hindbrain as well as greater numbers of TH-ir neurons in the preoptic area. These data provide evidence that catecholamines may function, in part, to seasonally modulate the sensitivity of the inner ear and, in turn, the appropriate behavioral response to reproductive acoustic

  9. Neurodevelopment genes in lampreys reveal trends for forebrain evolution in craniates.

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    Adèle Guérin

    Full Text Available The forebrain is the brain region which has undergone the most dramatic changes through vertebrate evolution. Analyses conducted in lampreys are essential to gain insight into the broad ancestral characteristics of the forebrain at the dawn of vertebrates, and to understand the molecular basis for the diversifications that have taken place in cyclostomes and gnathostomes following their splitting. Here, we report the embryonic expression patterns of 43 lamprey genes, coding for transcription factors or signaling molecules known to be involved in cell proliferation, stemcellness, neurogenesis, patterning and regionalization in the developing forebrain. Systematic expression patterns comparisons with model organisms highlight conservations likely to reflect shared features present in the vertebrate ancestors. They also point to changes in signaling systems -pathways which control the growth and patterning of the neuroepithelium-, which may have been crucial in the evolution of forebrain anatomy at the origin of vertebrates.

  10. Auditory evacuation beacons

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Bronkhorst, A.W.; Boer, L.C.

    2005-01-01

    Auditory evacuation beacons can be used to guide people to safe exits, even when vision is totally obscured by smoke. Conventional beacons make use of modulated noise signals. Controlled evacuation experiments show that such signals require explicit instructions and are often misunderstood. A new si

  11. Virtual Auditory Displays

    Science.gov (United States)

    2000-01-01

    timbre , intensity, distance, room modeling, radio communication Virtual Environments Handbook Chapter 4 Virtual Auditory Displays Russell D... musical note “A” as a pure sinusoid, there will be 440 condensations and rarefactions per second. The distance between two adjacent condensations or...and complexity are pitch, loudness, and timbre respectively. This distinction between physical and perceptual measures of sound properties is an

  12. The neglected neglect: auditory neglect.

    Science.gov (United States)

    Gokhale, Sankalp; Lahoti, Sourabh; Caplan, Louis R

    2013-08-01

    Whereas visual and somatosensory forms of neglect are commonly recognized by clinicians, auditory neglect is often not assessed and therefore neglected. The auditory cortical processing system can be functionally classified into 2 distinct pathways. These 2 distinct functional pathways deal with recognition of sound ("what" pathway) and the directional attributes of the sound ("where" pathway). Lesions of higher auditory pathways produce distinct clinical features. Clinical bedside evaluation of auditory neglect is often difficult because of coexisting neurological deficits and the binaural nature of auditory inputs. In addition, auditory neglect and auditory extinction may show varying degrees of overlap, which makes the assessment even harder. Shielding one ear from the other as well as separating the ear from space is therefore critical for accurate assessment of auditory neglect. This can be achieved by use of specialized auditory tests (dichotic tasks and sound localization tests) for accurate interpretation of deficits. Herein, we have reviewed auditory neglect with an emphasis on the functional anatomy, clinical evaluation, and basic principles of specialized auditory tests.

  13. Changes in Electroencephalogram Approximate Entropy Reflect Auditory Processing and Functional Complexity in Frogs

    Institute of Scientific and Technical Information of China (English)

    Yansu LIU; Yanzhu FAN; Fei XUE; Xizi YUE; Steven E BRAUTH; Yezhong TANG; Guangzhan FANG

    2016-01-01

    Brain systems engage in what are generally considered to be among the most complex forms of information processing. In the present study, we investigated the functional complexity of anuran auditory processing using the approximate entropy (ApEn) protocol for electroencephalogram (EEG) recordings from the forebrain and midbrain while male and female music frogs (Babina daunchina) listened to acoustic stimuli whose biological significance varied. The stimuli used were synthesized white noise (reflecting a novel signal), conspecific male advertisement calls with either high or low sexual attractiveness (relfecting sexual selection) and silence (relfecting a baseline). The results showed that 1) ApEn evoked by conspeciifc calls exceeded ApEn evoked by synthesized white noise in the left mesencephalon indicating this structure plays a critical role in processing acoustic signals with biological signiifcance;2) ApEn in the mesencephalon was significantly higher than for the telencephalon, consistent with the fact that the anuran midbrain contains a large well-organized auditory nucleus (torus semicircularis) while the forebrain does not; 3) for females ApEn in the mesencephalon was signiifcantly different than that of males, suggesting that males and females process biological stimuli related to mate choice differently.

  14. Enhanced representation of spectral contrasts in the primary auditory cortex

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    Nicolas eCatz

    2013-06-01

    Full Text Available The role of early auditory processing may be to extract some elementary features from an acoustic mixture in order to organize the auditory scene. To accomplish this task, the central auditory system may rely on the fact that sensory objects are often composed of spectral edges, i.e. regions where the stimulus energy changes abruptly over frequency. The processing of acoustic stimuli may benefit from a mechanism enhancing the internal representation of spectral edges. While the visual system is thought to rely heavily on this mechanism (enhancing spatial edges, it is still unclear whether a related process plays a significant role in audition. We investigated the cortical representation of spectral edges, using acoustic stimuli composed of multi-tone pips whose time-averaged spectral envelope contained suppressed or enhanced regions. Importantly, the stimuli were designed such that neural responses properties could be assessed as a function of stimulus frequency during stimulus presentation. Our results suggest that the representation of acoustic spectral edges is enhanced in the auditory cortex, and that this enhancement is sensitive to the characteristics of the spectral contrast profile, such as depth, sharpness and width. Spectral edges are maximally enhanced for sharp contrast and large depth. Cortical activity was also suppressed at frequencies within the suppressed region. To note, the suppression of firing was larger at frequencies nearby the lower edge of the suppressed region than at the upper edge. Overall, the present study gives critical insights into the processing of spectral contrasts in the auditory system.

  15. Auditory function in vestibular migraine

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    John Mathew

    2016-01-01

    Full Text Available Introduction: Vestibular migraine (VM is a vestibular syndrome seen in patients with migraine and is characterized by short spells of spontaneous or positional vertigo which lasts between a few seconds to weeks. Migraine and VM are considered to be a result of chemical abnormalities in the serotonin pathway. Neuhauser′s diagnostic criteria for vestibular migraine is widely accepted. Research on VM is still limited and there are few studies which have been published on this topic. Materials and Methods: This study has two parts. In the first part, we did a retrospective chart review of eighty consecutive patients who were diagnosed with vestibular migraine and determined the frequency of auditory dysfunction in these patients. The second part was a prospective case control study in which we compared the audiological parameters of thirty patients diagnosed with VM with thirty normal controls to look for any significant differences. Results: The frequency of vestibular migraine in our population is 22%. The frequency of hearing loss in VM is 33%. Conclusion: There is a significant difference between cases and controls with regards to the presence of distortion product otoacoustic emissions in both ears. This finding suggests that the hearing loss in VM is cochlear in origin.

  16. A hardware model of the auditory periphery to transduce acoustic signals into neural activity

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    Takashi eTateno

    2013-11-01

    Full Text Available To improve the performance of cochlear implants, we have integrated a microdevice into a model of the auditory periphery with the goal of creating a microprocessor. We constructed an artificial peripheral auditory system using a hybrid model in which polyvinylidene difluoride was used as a piezoelectric sensor to convert mechanical stimuli into electric signals. To produce frequency selectivity, the slit on a stainless steel base plate was designed such that the local resonance frequency of the membrane over the slit reflected the transfer function. In the acoustic sensor, electric signals were generated based on the piezoelectric effect from local stress in the membrane. The electrodes on the resonating plate produced relatively large electric output signals. The signals were fed into a computer model that mimicked some functions of inner hair cells, inner hair cell–auditory nerve synapses, and auditory nerve fibers. In general, the responses of the model to pure-tone burst and complex stimuli accurately represented the discharge rates of high-spontaneous-rate auditory nerve fibers across a range of frequencies greater than 1 kHz and middle to high sound pressure levels. Thus, the model provides a tool to understand information processing in the peripheral auditory system and a basic design for connecting artificial acoustic sensors to the peripheral auditory nervous system. Finally, we discuss the need for stimulus control with an appropriate model of the auditory periphery based on auditory brainstem responses that were electrically evoked by different temporal pulse patterns with the same pulse number.

  17. Lesions of the basal forebrain cholinergic system in mice disrupt idiothetic navigation.

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    Adam S Hamlin

    Full Text Available Loss of integrity of the basal forebrain cholinergic neurons is a consistent feature of Alzheimer's disease, and measurement of basal forebrain degeneration by magnetic resonance imaging is emerging as a sensitive diagnostic marker for prodromal disease. It is also known that Alzheimer's disease patients perform poorly on both real space and computerized cued (allothetic or uncued (idiothetic recall navigation tasks. Although the hippocampus is required for allothetic navigation, lesions of this region only mildly affect idiothetic navigation. Here we tested the hypothesis that the cholinergic medial septo-hippocampal circuit is important for idiothetic navigation. Basal forebrain cholinergic neurons were selectively lesioned in mice using the toxin saporin conjugated to a basal forebrain cholinergic neuronal marker, the p75 neurotrophin receptor. Control animals were able to learn and remember spatial information when tested on a modified version of the passive place avoidance test where all extramaze cues were removed, and animals had to rely on idiothetic signals. However, the exploratory behaviour of mice with cholinergic basal forebrain lesions was highly disorganized during this test. By contrast, the lesioned animals performed no differently from controls in tasks involving contextual fear conditioning and spatial working memory (Y maze, and displayed no deficits in potentially confounding behaviours such as motor performance, anxiety, or disturbed sleep/wake cycles. These data suggest that the basal forebrain cholinergic system plays a specific role in idiothetic navigation, a modality that is impaired early in Alzheimer's disease.

  18. From pluripotency to forebrain patterning: an in vitro journey astride embryonic stem cells.

    Science.gov (United States)

    Lupo, Giuseppe; Bertacchi, Michele; Carucci, Nicoletta; Augusti-Tocco, Gabriella; Biagioni, Stefano; Cremisi, Federico

    2014-08-01

    Embryonic stem cells (ESCs) have been used extensively as in vitro models of neural development and disease, with special efforts towards their conversion into forebrain progenitors and neurons. The forebrain is the most complex brain region, giving rise to several fundamental structures, such as the cerebral cortex, the hypothalamus, and the retina. Due to the multiplicity of signaling pathways playing different roles at distinct times of embryonic development, the specification and patterning of forebrain has been difficult to study in vivo. Research performed on ESCs in vitro has provided a large body of evidence to complement work in model organisms, but these studies have often been focused more on cell type production than on cell fate regulation. In this review, we systematically reassess the current literature in the field of forebrain development in mouse and human ESCs with a focus on the molecular mechanisms of early cell fate decisions, taking into consideration the specific culture conditions, exogenous and endogenous molecular cues as described in the original studies. The resulting model of early forebrain induction and patterning provides a useful framework for further studies aimed at reconstructing forebrain development in vitro for basic research or therapy.

  19. Complex and dynamic patterns of Wnt pathway gene expression in the developing chick forebrain

    Directory of Open Access Journals (Sweden)

    Lumsden Andrew

    2009-09-01

    Full Text Available Abstract Background Wnt signalling regulates multiple aspects of brain development in vertebrate embryos. A large number of Wnts are expressed in the embryonic forebrain; however, it is poorly understood which specific Wnt performs which function and how they interact. Wnts are able to activate different intracellular pathways, but which of these pathways become activated in different brain subdivisions also remains enigmatic. Results We have compiled the first comprehensive spatiotemporal atlas of Wnt pathway gene expression at critical stages of forebrain regionalisation in the chick embryo and found that most of these genes are expressed in strikingly dynamic and complex patterns. Several expression domains do not respect proposed compartment boundaries in the developing forebrain, suggesting that areal identities are more dynamic than previously thought. Using an in ovo electroporation approach, we show that Wnt4 expression in the thalamus is negatively regulated by Sonic hedgehog (Shh signalling from the zona limitans intrathalamica (ZLI, a known organising centre of forebrain development. Conclusion The forebrain is exposed to a multitude of Wnts and Wnt inhibitors that are expressed in a highly dynamic and complex fashion, precluding simple correlative conclusions about their respective functions or signalling mechanisms. In various biological systems, Wnts are antagonised by Shh signalling. By demonstrating that Wnt4 expression in the thalamus is repressed by Shh from the ZLI we reveal an additional level of interaction between these two pathways and provide an example for the cross-regulation between patterning centres during forebrain regionalisation.

  20. Expanded expression of Sonic Hedgehog in Astyanax cavefish: multiple consequences on forebrain development and evolution.

    Science.gov (United States)

    Menuet, Arnaud; Alunni, Alessandro; Joly, Jean-Stéphane; Jeffery, William R; Rétaux, Sylvie

    2007-03-01

    Ventral midline Sonic Hedgehog (Shh) signalling is crucial for growth and patterning of the embryonic forebrain. Here, we report how enhanced Shh midline signalling affects the evolution of telencephalic and diencephalic neuronal patterning in the blind cavefish Astyanax mexicanus, a teleost fish closely related to zebrafish. A comparison between cave- and surface-dwelling forms of Astyanax shows that cavefish display larger Shh expression in all anterior midline domains throughout development. This does not affect global forebrain regional patterning, but has several important consequences on specific regions and neuronal populations. First, we show expanded Nkx2.1a expression and higher levels of cell proliferation in the cavefish basal diencephalon and hypothalamus. Second, we uncover an Nkx2.1b-Lhx6-GABA-positive migratory pathway from the subpallium to the olfactory bulb, which is increased in size in cavefish. Finally, we observe heterochrony and enlarged Lhx7 expression in the cavefish basal forebrain. These specific increases in olfactory and hypothalamic forebrain components are Shh-dependent and therefore place the telencephalic midline organisers in a crucial position to modulate forebrain evolution through developmental events, and to generate diversity in forebrain neuronal patterning.

  1. Forebrain commissures and visual memory: a new approach.

    Science.gov (United States)

    Doty, R W; Ringo, J L; Lewine, J D

    1988-08-01

    The primary purpose of these exploratory experiments was to determine: (1) whether the forebrain commissures can provide full accessibility of the mnemonic store to either hemisphere when the taks involves memory for 'events' (images) rather than, as in essentially all previous tests on split-brain animals, memory for 'rules' (discrimination habits); and (2) whether the anterior commissure (AC) alone is capable of such function. Macaques, with optic chiasm transected to allow limitation of direct visual input to one or the other hemisphere, were trained on tasks requiring recognition of previously viewed photographic slides. For one task, delayed-matching-to-sample (DMTS), the animal was presented with a 'sample' image, and then 0-15s later was required to choose that image in preference to a second image concurrently displayed. On the other task, running recognition (RR), a series of images was presented, some of which were repetitions of images previously seen in that session, and the animal was required to signal its recognition of these repetitions. For either task the initial presentation could be made to one eye and hemisphere, and subsequent recognition required of the other. In such circumstance, if all forebrain commissures were divided, such interhemispheric recognition was no longer possible. For the DMTS task if either the AC or 5 mm of the splenium of the corpus callosum were available, interhemispheric recognition was basically equivalent to that using the same eye and hemisphere. However, interhemispheric accuracy with the RR task, while well above chance levels, was consistently inferior to that achieved intrahemispherically when complex scenes or objects were viewed. This is probably a consequence mostly of the differing visual fields of the two eyes, since interhemispheric accuracy was greatly improved by use of images having approximately identical right and left halves. No consistent hemispheric specialization nor difference in direction of

  2. PLASTICITY IN THE ADULT CENTRAL AUDITORY SYSTEM.

    Science.gov (United States)

    Irvine, Dexter R F; Fallon, James B; Kamke, Marc R

    2006-04-01

    The central auditory system retains into adulthood a remarkable capacity for plastic changes in the response characteristics of single neurons and the functional organization of groups of neurons. The most dramatic examples of this plasticity are provided by changes in frequency selectivity and organization as a consequence of either partial hearing loss or procedures that alter the significance of particular frequencies for the organism. Changes in temporal resolution are also seen as a consequence of altered experience. These forms of plasticity are likely to contribute to the improvements exhibited by cochlear implant users in the post-implantation period.

  3. PLASTICITY IN THE ADULT CENTRAL AUDITORY SYSTEM

    Science.gov (United States)

    Irvine, Dexter R. F.; Fallon, James B.; Kamke, Marc R.

    2007-01-01

    The central auditory system retains into adulthood a remarkable capacity for plastic changes in the response characteristics of single neurons and the functional organization of groups of neurons. The most dramatic examples of this plasticity are provided by changes in frequency selectivity and organization as a consequence of either partial hearing loss or procedures that alter the significance of particular frequencies for the organism. Changes in temporal resolution are also seen as a consequence of altered experience. These forms of plasticity are likely to contribute to the improvements exhibited by cochlear implant users in the post-implantation period. PMID:17572797

  4. Cochlear Responses and Auditory Brainstem Response Functions in Adults with Auditory Neuropathy/ Dys-Synchrony and Individuals with Normal Hearing

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2007-06-01

    Full Text Available Background and Aim: Physiologic measures of cochlear and auditory nerve function may be of assis¬tance in distinguishing between hearing disorders due primarily to auditory nerve impairment from those due primarily to cochlear hair cells dysfunction. The goal of present study was to measure of co-chlear responses (otoacoustic emissions and cochlear microphonics and auditory brainstem response in some adults with auditory neuropathy/ dys-synchrony and subjects with normal hearing. Materials and Methods: Patients were 16 adults (32 ears in age range of 14-30 years with auditory neu¬ropathy/ dys-synchrony and 16 individuals in age range of 16-30 years from both sexes. The results of transient otoacoustic emissions, cochlear microphonics and auditory brainstem response measures were compared in both groups and the effects of age, sex, ear and degree of hearing loss were studied. Results: The pure-tone average was 48.1 dB HL in auditory neuropathy/dys-synchrony group and the fre¬quency of low tone loss and flat audiograms were higher among other audiogram's shapes. Transient oto¬acoustic emissions were shown in all auditory neuropathy/dys-synchrony people except two cases and its average was near in both studied groups. The latency and amplitude of the biggest reversed co-chlear microphonics response were higher in auditory neuropathy/dys-synchrony patients than control peo¬ple significantly. The correlation between cochlear microphonics amplitude and degree of hearing loss was not significant, and age had significant effect in some cochlear microphonics measures. Audi-tory brainstem response had no response in auditory neuropathy/dys-synchrony patients even with low stim¬uli rates. Conclusion: In adults with speech understanding worsen than predicted from the degree of hearing loss that suspect to auditory neuropathy/ dys-synchrony, the frequency of low tone loss and flat audiograms are higher. Usually auditory brainstem response is absent in

  5. Increased BOLD Signals Elicited by High Gamma Auditory Stimulation of the Left Auditory Cortex in Acute State Schizophrenia.

    Science.gov (United States)

    Kuga, Hironori; Onitsuka, Toshiaki; Hirano, Yoji; Nakamura, Itta; Oribe, Naoya; Mizuhara, Hiroaki; Kanai, Ryota; Kanba, Shigenobu; Ueno, Takefumi

    2016-10-01

    Recent MRI studies have shown that schizophrenia is characterized by reductions in brain gray matter, which progress in the acute state of the disease. Cortical circuitry abnormalities in gamma oscillations, such as deficits in the auditory steady state response (ASSR) to gamma frequency (>30-Hz) stimulation, have also been reported in schizophrenia patients. In the current study, we investigated neural responses during click stimulation by BOLD signals. We acquired BOLD responses elicited by click trains of 20, 30, 40 and 80-Hz frequencies from 15 patients with acute episode schizophrenia (AESZ), 14 symptom-severity-matched patients with non-acute episode schizophrenia (NASZ), and 24 healthy controls (HC), assessed via a standard general linear-model-based analysis. The AESZ group showed significantly increased ASSR-BOLD signals to 80-Hz stimuli in the left auditory cortex compared with the HC and NASZ groups. In addition, enhanced 80-Hz ASSR-BOLD signals were associated with more severe auditory hallucination experiences in AESZ participants. The present results indicate that neural over activation occurs during 80-Hz auditory stimulation of the left auditory cortex in individuals with acute state schizophrenia. Given the possible association between abnormal gamma activity and increased glutamate levels, our data may reflect glutamate toxicity in the auditory cortex in the acute state of schizophrenia, which might lead to progressive changes in the left transverse temporal gyrus.

  6. Potenciais evocados auditivos de tronco encefálico por frequência específica e de estado estável na audiologia pediátrica: estudo de caso Frequency-specific and steady-state evoked auditory brainstem responses in pediatric audiology: case study

    Directory of Open Access Journals (Sweden)

    Gabriela Ribeiro Ivo Rodrigues

    2009-01-01

    Full Text Available Preconiza-se o diagnóstico até os três meses de idade em crianças com deficiência auditiva congênita. Após a etapa inicial de confirmação do diagnóstico, é necessário que se obtenha limiares precisos nas diferentes frequências, para que seja possível uma adequada seleção, indicação e regulagem de aparelhos de amplificação sonora. Nesse contexto, inserem-se os Potenciais Evocados Auditivos de Tronco Encefálico por Frequência Específica (PEATE-FE e, mais recentemente, os Potenciais Evocados Auditivos de Estado Estável (PEAEE. O objetivo deste estudo de caso foi apresentar os achados das duas técnicas para estimar os limiares auditivos em uma criança de três meses de idade, com perda auditiva neurossensorial bilateral, diagnosticada utilizando-se como primeiro método de avaliação os Potenciais Evocados Auditivos de Tronco Encefálico com estímulo clique, tanto por via aérea como por via óssea. As duas técnicas mostraram-se eficientes para estimar os limiares auditivos, com uma vantagem dos PEAEE com relação ao tempo de duração de exame.It is recommended that congenital hearing loss is identified as early as three months old. After the initial step of confirming the diagnosis, it is necessary to obtain accurate hearing thresholds, allowing an adequate selection, indication and regulation of hearing aids for these children. It is inserted, in this context, the Frequency-Specific Auditory Brainstem Responses (FSABR and, more recently, the Auditory Steady-State Responses (ASSR. The aim of the present study was to describe the findings of the use of both techniques to estimate the auditory thresholds of a three-month-old infant with bilateral sensorineural hearing loss diagnosed using, as primary evaluation method, the click-evoked Auditory Brainstem Responses, with both air and bone stimuli conduction. Both techniques provided reliable findings for estimating auditory thresholds. The ASSR had an advantage regarding

  7. Topography of acoustic response characteristics in the auditory cortex of the Kunming mouse

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Topography of acoustic response characteristics in the auditory cortex (AC) of the Kunming (KM) mouse has been examined by using microelectrode recording techniques.Based on best-frequency (BF) maps,both the primary auditory field (AⅠ) and the anterior auditory field (AAF) are tonotopically organized with a counter running frequency gradient.Within an isofrequency stripe,the width of the frequency-threshold curves of single neurons increases,and minimum threshold (MT) decreases towards more ventral locations.BFs in AⅠand AAF range from 4 to 38 kHz.Auditory neurons with BFs above 40 kHz are located at the rostrodorsal part of the AC.The findings suggest that the KM mouse is a good model suitable for auditory research.

  8. Selective increase of auditory cortico-striatal coherence during auditory-cued Go/NoGo discrimination learning.

    Directory of Open Access Journals (Sweden)

    Andreas L. Schulz

    2016-01-01

    Full Text Available Goal directed behavior and associated learning processes are tightly linked to neuronal activity in the ventral striatum. Mechanisms that integrate task relevant sensory information into striatal processing during decision making and learning are implicitly assumed in current reinforcementmodels, yet they are still weakly understood. To identify the functional activation of cortico-striatal subpopulations of connections during auditory discrimination learning, we trained Mongolian gerbils in a two-way active avoidance task in a shuttlebox to discriminate between falling and rising frequency modulated tones with identical spectral properties. We assessed functional coupling by analyzing the field-field coherence between the auditory cortex and the ventral striatum of animals performing the task. During the course of training, we observed a selective increase of functionalcoupling during Go-stimulus presentations. These results suggest that the auditory cortex functionally interacts with the ventral striatum during auditory learning and that the strengthening of these functional connections is selectively goal-directed.

  9. Investigative effects of low frequency repetitive transcranial magnetic stimulation combined with drugs on obstinate auditory hallucinations and cognitive function in patients with schizophrenia%低频重复经颅刺激联合药物干预对精神分裂症患者顽固性幻听和认知功能的影响效果探析

    Institute of Scientific and Technical Information of China (English)

    马继东; 潘赞; 田洪伟; 王朝

    2015-01-01

    Objective To explore the clinical value of low frequency repetitive transcranial magnetic stimulation in improving obstinate auditory hallucinations and cognitive function in patients with schizophrenia. Methods According to visiting order number, 128 patients with schizophrenia were divided into control group and observation group.The observation group was treated by low frequency repetitive transcranial magnetic stimulation combined with risperidone, the control group was treated with risperidone.Before and after treatment, the patients were evaluated, by auditory hallucinations rating scale( AHRS) and assessment of verbal fluency and trail making were performed in patients.Results There was no significant difference in AHRS scores, VFT scores and trail making between the two groups before treatment (P>0.05).After treatment, the AHRS scores in the observation group were lower than that in the control group, the VFT scores in the observation group were higher than that in the control group, with statistical significance between two groups (P0.05).治疗后,观察组AHRS评分低于对照组,VFT评分则升高明显,差异具统计学意义( P<0.05). 结论 低频重复经颅刺激联合药物干预可较好的改善精神分裂症患者顽固性幻听,以及语言方面的认知功能.

  10. Auditory pathways: anatomy and physiology.

    Science.gov (United States)

    Pickles, James O

    2015-01-01

    This chapter outlines the anatomy and physiology of the auditory pathways. After a brief analysis of the external, middle ears, and cochlea, the responses of auditory nerve fibers are described. The central nervous system is analyzed in more detail. A scheme is provided to help understand the complex and multiple auditory pathways running through the brainstem. The multiple pathways are based on the need to preserve accurate timing while extracting complex spectral patterns in the auditory input. The auditory nerve fibers branch to give two pathways, a ventral sound-localizing stream, and a dorsal mainly pattern recognition stream, which innervate the different divisions of the cochlear nucleus. The outputs of the two streams, with their two types of analysis, are progressively combined in the inferior colliculus and onwards, to produce the representation of what can be called the "auditory objects" in the external world. The progressive extraction of critical features in the auditory stimulus in the different levels of the central auditory system, from cochlear nucleus to auditory cortex, is described. In addition, the auditory centrifugal system, running from cortex in multiple stages to the organ of Corti of the cochlea, is described.

  11. Animal models for auditory streaming.

    Science.gov (United States)

    Itatani, Naoya; Klump, Georg M

    2017-02-19

    Sounds in the natural environment need to be assigned to acoustic sources to evaluate complex auditory scenes. Separating sources will affect the analysis of auditory features of sounds. As the benefits of assigning sounds to specific sources accrue to all species communicating acoustically, the ability for auditory scene analysis is widespread among different animals. Animal studies allow for a deeper insight into the neuronal mechanisms underlying auditory scene analysis. Here, we will review the paradigms applied in the study of auditory scene analysis and streaming of sequential sounds in animal models. We will compare the psychophysical results from the animal studies to the evidence obtained in human psychophysics of auditory streaming, i.e. in a task commonly used for measuring the capability for auditory scene analysis. Furthermore, the neuronal correlates of auditory streaming will be reviewed in different animal models and the observations of the neurons' response measures will be related to perception. The across-species comparison will reveal whether similar demands in the analysis of acoustic scenes have resulted in similar perceptual and neuronal processing mechanisms in the wide range of species being capable of auditory scene analysis.This article is part of the themed issue 'Auditory and visual scene analysis'.

  12. Dopamine receptor gene expression by enkephalin neurons in rat forebrain

    Energy Technology Data Exchange (ETDEWEB)

    Le Moine, C.; Normand, E.; Guitteny, A.F.; Fouque, B.; Teoule, R.; Bloch, B. (Universite de Bordeaux II (France))

    1990-01-01

    In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons.

  13. Regional energy balance in rat brain after transient forebrain ischemia.

    Science.gov (United States)

    Pulsinelli, W A; Duffy, T E

    1983-05-01

    Phosphocreatine, ATP, and glucose were severely depleted, and the lactate levels were increased in the paramedian neocortex, dorsal-lateral striatum, and CA1 zone of hippocampus of rats exposed to 30 min of forebrain ischemia. Upon recirculation of the brain, phosphocreatine, ATP, and lactate concentrations recovered to control values in the paramedian neocortex and CA1 zone of hippocampus and to near-control values in the striatum. The phosphocreatine and ATP concentrations then fell and the lactate levels rose in the striatum after 6-24 h, and in the CA1 zone of hippocampus after 24-72 h. The initial recovery and subsequent delayed changes in the phosphocreatine, ATP, and lactate concentrations in the striatum and hippocampus coincided with the onset and progression of morphological injury in these brain regions. The results suggest that cells in these regions regain normal or near-normal mitochondrial function and are viable, in terms of energy production, for many hours before unknown mechanisms cause irreversible neuronal before unknown mechanisms cause irreversible neuronal injury.

  14. Probing forebrain to hindbrain circuit functions in Xenopus.

    Science.gov (United States)

    Kelley, Darcy B; Elliott, Taffeta M; Evans, Ben J; Hall, Ian C; Leininger, Elizabeth C; Rhodes, Heather J; Yamaguchi, Ayako; Zornik, Erik

    2017-01-01

    The vertebrate hindbrain includes neural circuits that govern essential functions including breathing, blood pressure and heart rate. Hindbrain circuits also participate in generating rhythmic motor patterns for vocalization. In most tetrapods, sound production is powered by expiration and the circuitry underlying vocalization and respiration must be linked. Perception and arousal are also linked; acoustic features of social communication sounds-for example, a baby's cry-can drive autonomic responses. The close links between autonomic functions that are essential for life and vocal expression have been a major in vivo experimental challenge. Xenopus provides an opportunity to address this challenge using an ex vivo preparation: an isolated brain that generates vocal and breathing patterns. The isolated brain allows identification and manipulation of hindbrain vocal circuits as well as their activation by forebrain circuits that receive sensory input, initiate motor patterns and control arousal. Advances in imaging technologies, coupled to the production of Xenopus lines expressing genetically encoded calcium sensors, provide powerful tools for imaging neuronal patterns in the entire fictively behaving brain, a goal of the BRAIN Initiative. Comparisons of neural circuit activity across species (comparative neuromics) with distinctive vocal patterns can identify conserved features, and thereby reveal essential functional components.

  15. Representation of lateralization and tonotopy in primary versus secondary human auditory cortex

    NARCIS (Netherlands)

    Langers, Dave R. M.; Backes, Walter H.; van Dijk, Pim

    2007-01-01

    Functional MRI was performed to investigate differences in the basic functional organization of the primary and secondary auditory cortex regarding preferred stimulus lateratization and frequency. A modified sparse acquisition scheme was used to spatially map the characteristics of the auditory cort

  16. The Relationship between Auditory Processing and Restricted, Repetitive Behaviors in Adults with Autism Spectrum Disorders

    Science.gov (United States)

    Kargas, Niko; López, Beatriz; Reddy, Vasudevi; Morris, Paul

    2015-01-01

    Current views suggest that autism spectrum disorders (ASDs) are characterised by enhanced low-level auditory discrimination abilities. Little is known, however, about whether enhanced abilities are universal in ASD and how they relate to symptomatology. We tested auditory discrimination for intensity, frequency and duration in 21 adults with ASD…

  17. An Auditory Model with Hearing Loss

    DEFF Research Database (Denmark)

    Nielsen, Lars Bramsløw

    An auditory model based on the psychophysics of hearing has been developed and tested. The model simulates the normal ear or an impaired ear with a given hearing loss. Based on reviews of the current literature, the frequency selectivity and loudness growth as functions of threshold and stimulus...... level have been found and implemented in the model. The auditory model was verified against selected results from the literature, and it was confirmed that the normal spread of masking and loudness growth could be simulated in the model. The effects of hearing loss on these parameters was also...... in qualitative agreement with recent findings. The temporal properties of the ear have currently not been included in the model. As an example of a real-world application of the model, loudness spectrograms for a speech utterance were presented. By introducing hearing loss, the speech sounds became less audible...

  18. Anatomy and Physiology of the Auditory Tracts

    Directory of Open Access Journals (Sweden)

    Mohammad hosein Hekmat Ara

    1999-03-01

    Full Text Available Hearing is one of the excel sense of human being. Sound waves travel through the medium of air and enter the ear canal and then hit the tympanic membrane. Middle ear transfer almost 60-80% of this mechanical energy to the inner ear by means of “impedance matching”. Then, the sound energy changes to traveling wave and is transferred based on its specific frequency and stimulates organ of corti. Receptors in this organ and their synapses transform mechanical waves to the neural waves and transfer them to the brain. The central nervous system tract of conducting the auditory signals in the auditory cortex will be explained here briefly.

  19. 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...

  20. Neurophysiological mechanisms involved in auditory perceptual organization

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    Aurélie Bidet-Caulet

    2009-09-01

    Full Text Available In our complex acoustic environment, we are confronted with a mixture of sounds produced by several simultaneous sources. However, we rarely perceive these sounds as incomprehensible noise. Our brain uses perceptual organization processes to independently follow the emission of each sound source over time. If the acoustic properties exploited in these processes are well-established, the neurophysiological mechanisms involved in auditory scene analysis have raised interest only recently. Here, we review the studies investigating these mechanisms using electrophysiological recordings from the cochlear nucleus to the auditory cortex, in animals and humans. Their findings reveal that basic mechanisms such as frequency selectivity, forward suppression and multi-second habituation shape the automatic brain responses to sounds in a way that can account for several important characteristics of perceptual organization of both simultaneous and successive sounds. One challenging question remains unresolved: how are the resulting activity patterns integrated to yield the corresponding conscious perceptsµ

  1. Resizing Auditory Communities

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2012-01-01

    Heard through the ears of the Canadian composer and music teacher R. Murray Schafer the ideal auditory community had the shape of a village. Schafer’s work with the World Soundscape Project in the 70s represent an attempt to interpret contemporary environments through musical and auditory...... parameters highlighting harmonious and balanced qualities while criticizing the noisy and cacophonous qualities of modern urban settings. This paper present a reaffirmation of Schafer’s central methodological claim: that environments can be analyzed through their sound, but offers considerations on the role...... musicalized through electro acoustic equipment installed in shops, shopping streets, transit areas etc. Urban noise no longer acts only as disturbance, but also structure and shape the places and spaces in which urban life enfold. Based on research done in Japanese shopping streets and in Copenhagen the paper...

  2. Central projections of auditory receptor neurons of crickets.

    Science.gov (United States)

    Imaizumi, Kazuo; Pollack, Gerald S

    2005-12-19

    We describe the central projections of physiologically characterized auditory receptor neurons of crickets as revealed by confocal microscopy. Receptors tuned to ultrasonic frequencies (similar to those produced by echolocating, insectivorous bats), to a mid-range of frequencies, and a subset of those tuned to low, cricket-like frequencies have similar projections, terminating medially within the auditory neuropile. Quantitative analysis shows that despite the general similarity of these projections they are tonotopic, with receptors tuned to lower frequencies terminating more medially. Another subset of cricket-song-tuned receptors projects more laterally and posteriorly than the other types. Double-fills of receptors and identified interneurons show that the three medially projecting receptor types are anatomically well positioned to provide monosynaptic input to interneurons that relay auditory information to the brain and to interneurons that modify this ascending information. The more laterally and posteriorly branching receptor type may not interact directly with this ascending pathway, but is well positioned to provide direct input to an interneuron that carries auditory information to more posterior ganglia. These results suggest that information about cricket song is segregated into functionally different pathways as early as the level of receptor neurons. Ultrasound-tuned and mid-frequency tuned receptors have approximately twice as many varicosities, which are sites of transmitter release, per receptor as either anatomical type of cricket-song-tuned receptor. This may compensate in part for the numerical under-representation of these receptor types.

  3. An auditory feature detection circuit for sound pattern recognition.

    Science.gov (United States)

    Schöneich, Stefan; Kostarakos, Konstantinos; Hedwig, Berthold

    2015-09-01

    From human language to birdsong and the chirps of insects, acoustic communication is based on amplitude and frequency modulation of sound signals. Whereas frequency processing starts at the level of the hearing organs, temporal features of the sound amplitude such as rhythms or pulse rates require processing by central auditory neurons. Besides several theoretical concepts, brain circuits that detect temporal features of a sound signal are poorly understood. We focused on acoustically communicating field crickets and show how five neurons in the brain of females form an auditory feature detector circuit for the pulse pattern of the male calling song. The processing is based on a coincidence detector mechanism that selectively responds when a direct neural response and an intrinsically delayed response to the sound pulses coincide. This circuit provides the basis for auditory mate recognition in field crickets and reveals a principal mechanism of sensory processing underlying the perception of temporal patterns.

  4. An anatomical and functional topography of human auditory cortical areas.

    Science.gov (United States)

    Moerel, Michelle; De Martino, Federico; Formisano, Elia

    2014-01-01

    While advances in magnetic resonance imaging (MRI) throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla). Importantly, we illustrate that-whereas a group-based approach to analyze functional (tonotopic) maps is appropriate to highlight the main tonotopic axis-the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e., myelination) as well as of functional properties (e.g., broadness of frequency tuning) is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post-mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  5. An anatomical and functional topography of human auditory cortical areas

    Directory of Open Access Journals (Sweden)

    Michelle eMoerel

    2014-07-01

    Full Text Available While advances in magnetic resonance imaging (MRI throughout the last decades have enabled the detailed anatomical and functional inspection of the human brain non-invasively, to date there is no consensus regarding the precise subdivision and topography of the areas forming the human auditory cortex. Here, we propose a topography of the human auditory areas based on insights on the anatomical and functional properties of human auditory areas as revealed by studies of cyto- and myelo-architecture and fMRI investigations at ultra-high magnetic field (7 Tesla. Importantly, we illustrate that - whereas a group-based approach to analyze functional (tonotopic maps is appropriate to highlight the main tonotopic axis - the examination of tonotopic maps at single subject level is required to detail the topography of primary and non-primary areas that may be more variable across subjects. Furthermore, we show that considering multiple maps indicative of anatomical (i.e. myelination as well as of functional properties (e.g. broadness of frequency tuning is helpful in identifying auditory cortical areas in individual human brains. We propose and discuss a topography of areas that is consistent with old and recent anatomical post mortem characterizations of the human auditory cortex and that may serve as a working model for neuroscience studies of auditory functions.

  6. Behind the Scenes of Auditory Perception

    OpenAIRE

    Shamma, Shihab A.; Micheyl, Christophe

    2010-01-01

    Auditory scenes” often contain contributions from multiple acoustic sources. These are usually heard as separate auditory “streams”, which can be selectively followed over time. How and where these auditory streams are formed in the auditory system is one of the most fascinating questions facing auditory scientists today. Findings published within the last two years indicate that both cortical and sub-cortical processes contribute to the formation of auditory streams, and they raise importan...

  7. Association of basal forebrain volumes and cognition in normal aging.

    Science.gov (United States)

    Wolf, D; Grothe, M; Fischer, F U; Heinsen, H; Kilimann, I; Teipel, S; Fellgiebel, A

    2014-01-01

    The basal forebrain cholinergic system (BFCS) is known to undergo moderate neurodegenerative alterations during normal aging and severe atrophy in Alzheimer's disease (AD). It has been suggested that functional and structural alterations of the BFCS mediate cognitive performance in normal aging and AD. But, it is still unclear to what extend age-associated cognitive decline can be related to BFCS in normal aging. We analyzed the relationship between BFCS volume and cognition using MRI and a comprehensive neuropsychological test battery in a cohort of 43 healthy elderly subjects spanning the age range from 60 to 85 years. Most notably, we found significant associations between general intelligence and BFCS volumes, specifically within areas corresponding to posterior nuclei of the nucleus basalis of Meynert (Ch4p) and the nucleus subputaminalis (NSP). Associations between specific cognitive domains and BFCS volumes were less pronounced. Supplementary analyses demonstrated that especially the volume of NSP but also the volume of Ch4p was related to the volume of widespread temporal, frontal, and parietal gray and white matter regions. Volumes of these gray and white matter regions were also related to general intelligence. Higher volumes of Ch4p and NSP may enhance the effectiveness of acetylcholine supply in related gray and white matter regions underlying general intelligence and hence explain the observed association between the volume of Ch4p as well as NSP and general intelligence. Since general intelligence is known to attenuate the degree of age-associated cognitive decline and the risk of developing late-onset AD, the BFCS might, besides the specific contribution to the pathophysiology in AD, constitute a mechanism of brain resilience in normal aging.

  8. Impact of basal forebrain cholinergic inputs on basolateral amygdala neurons.

    Science.gov (United States)

    Unal, Cagri T; Pare, Denis; Zaborszky, Laszlo

    2015-01-14

    In addition to innervating the cerebral cortex, basal forebrain cholinergic (BFc) neurons send a dense projection to the basolateral nucleus of the amygdala (BLA). In this study, we investigated the effect of near physiological acetylcholine release on BLA neurons using optogenetic tools and in vitro patch-clamp recordings. Adult transgenic mice expressing cre-recombinase under the choline acetyltransferase promoter were used to selectively transduce BFc neurons with channelrhodopsin-2 and a reporter through the injection of an adeno-associated virus. Light-induced stimulation of BFc axons produced different effects depending on the BLA cell type. In late-firing interneurons, BFc inputs elicited fast nicotinic EPSPs. In contrast, no response could be detected in fast-spiking interneurons. In principal BLA neurons, two different effects were elicited depending on their activity level. When principal BLA neurons were quiescent or made to fire at low rates by depolarizing current injection, light-induced activation of BFc axons elicited muscarinic IPSPs. In contrast, with stronger depolarizing currents, eliciting firing above ∼ 6-8 Hz, these muscarinic IPSPs lost their efficacy because stimulation of BFc inputs prolonged current-evoked afterdepolarizations. All the effects observed in principal neurons were dependent on muscarinic receptors type 1, engaging different intracellular mechanisms in a state-dependent manner. Overall, our results suggest that acetylcholine enhances the signal-to-noise ratio in principal BLA neurons. Moreover, the cholinergic engagement of afterdepolarizations may contribute to the formation of stimulus associations during fear-conditioning tasks where the timing of conditioned and unconditioned stimuli is not optimal for the induction of synaptic plasticity.

  9. The impact of educational level on performance on auditory processing tests

    Directory of Open Access Journals (Sweden)

    Cristina F.B. Murphy

    2016-03-01

    Full Text Available Research has demonstrated that a higher level of education is associated with better performance on cognitive tests among middle-aged and elderly people. However, the effects of education on auditory processing skills have not yet been evaluated. Previous demonstrations of sensory-cognitive interactions in the aging process indicate the potential importance of this topic. Therefore, the primary purpose of this study was to investigate the performance of middle-aged and elderly people with different levels of formal education on auditory processing tests. A total of 177 adults with no evidence of cognitive, psychological or neurological conditions took part in the research. The participants completed a series of auditory assessments, including dichotic digit, frequency pattern and speech-in-noise tests. A working memory test was also performed to investigate the extent to which auditory processing and cognitive performance were associated. The results demonstrated positive but weak correlations between years of schooling and performance on all of the tests applied. The factor years of schooling was also one of the best predictors of frequency pattern and speech-in-noise test performance. Additionally, performance on the working memory, frequency pattern and dichotic digit tests was also correlated, suggesting that the influence of educational level on auditory processing performance might be associated with the cognitive demand of the auditory processing tests rather than auditory sensory aspects itself. Longitudinal research is required to investigate the causal relationship between educational level and auditory processing skills.

  10. Fgf16 is required for specification of GABAergic neurons and oligodendrocytes in the zebrafish forebrain.

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    Ayumi Miyake

    Full Text Available Fibroblast growth factor (Fgf signaling plays crucial roles in various developmental processes including those in the brain. We examined the role of Fgf16 in the formation of the zebrafish brain. The knockdown of fgf16 decreased cell proliferation in the forebrain and midbrain. fgf16 was also essential for development of the ventral telencephalon and diencephalon, whereas fgf16 was not required for dorsoventral patterning in the midbrain. fgf16 was additionally required for the specification and differentiation of γ-aminobutyric acid (GABAergic interneurons and oligodendrocytes, but not for those of glutamatergic neurons in the forebrain. Cross talk between Fgf and Hedgehog (Hh signaling was critical for the specification of GABAergic interneurons and oligodendrocytes. The expression of fgf16 in the forebrain was down-regulated by the inhibition of Hh and Fgf19 signaling, but not by that of Fgf3/Fgf8 signaling. The fgf16 morphant phenotype was similar to that of the fgf19 morphant and embryos blocked Hh signaling. The results of the present study indicate that Fgf16 signaling, which is regulated by the downstream pathways of Hh-Fgf19 in the forebrain, is involved in forebrain development.

  11. Auditory and non-auditory effects of noise on health

    NARCIS (Netherlands)

    Basner, M.; Babisch, W.; Davis, A.; Brink, M.; Clark, C.; Janssen, S.A.; Stansfeld, S.

    2013-01-01

    Noise is pervasive in everyday life and can cause both auditory and non-auditory health eff ects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mec

  12. Auditory Sketches: Very Sparse Representations of Sounds Are Still Recognizable.

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    Vincent Isnard

    Full Text Available Sounds in our environment like voices, animal calls or musical instruments are easily recognized by human listeners. Understanding the key features underlying this robust sound recognition is an important question in auditory science. Here, we studied the recognition by human listeners of new classes of sounds: acoustic and auditory sketches, sounds that are severely impoverished but still recognizable. Starting from a time-frequency representation, a sketch is obtained by keeping only sparse elements of the original signal, here, by means of a simple peak-picking algorithm. Two time-frequency representations were compared: a biologically grounded one, the auditory spectrogram, which simulates peripheral auditory filtering, and a simple acoustic spectrogram, based on a Fourier transform. Three degrees of sparsity were also investigated. Listeners were asked to recognize the category to which a sketch sound belongs: singing voices, bird calls, musical instruments, and vehicle engine noises. Results showed that, with the exception of voice sounds, very sparse representations of sounds (10 features, or energy peaks, per second could be recognized above chance. No clear differences could be observed between the acoustic and the auditory sketches. For the voice sounds, however, a completely different pattern of results emerged, with at-chance or even below-chance recognition performances, suggesting that the important features of the voice, whatever they are, were removed by the sketch process. Overall, these perceptual results were well correlated with a model of auditory distances, based on spectro-temporal excitation patterns (STEPs. This study confirms the potential of these new classes of sounds, acoustic and auditory sketches, to study sound recognition.

  13. Auditory Sketches: Very Sparse Representations of Sounds Are Still Recognizable.

    Science.gov (United States)

    Isnard, Vincent; Taffou, Marine; Viaud-Delmon, Isabelle; Suied, Clara

    2016-01-01

    Sounds in our environment like voices, animal calls or musical instruments are easily recognized by human listeners. Understanding the key features underlying this robust sound recognition is an important question in auditory science. Here, we studied the recognition by human listeners of new classes of sounds: acoustic and auditory sketches, sounds that are severely impoverished but still recognizable. Starting from a time-frequency representation, a sketch is obtained by keeping only sparse elements of the original signal, here, by means of a simple peak-picking algorithm. Two time-frequency representations were compared: a biologically grounded one, the auditory spectrogram, which simulates peripheral auditory filtering, and a simple acoustic spectrogram, based on a Fourier transform. Three degrees of sparsity were also investigated. Listeners were asked to recognize the category to which a sketch sound belongs: singing voices, bird calls, musical instruments, and vehicle engine noises. Results showed that, with the exception of voice sounds, very sparse representations of sounds (10 features, or energy peaks, per second) could be recognized above chance. No clear differences could be observed between the acoustic and the auditory sketches. For the voice sounds, however, a completely different pattern of results emerged, with at-chance or even below-chance recognition performances, suggesting that the important features of the voice, whatever they are, were removed by the sketch process. Overall, these perceptual results were well correlated with a model of auditory distances, based on spectro-temporal excitation patterns (STEPs). This study confirms the potential of these new classes of sounds, acoustic and auditory sketches, to study sound recognition.

  14. Visual speech gestures modulate efferent auditory system.

    Science.gov (United States)

    Namasivayam, Aravind Kumar; Wong, Wing Yiu Stephanie; Sharma, Dinaay; van Lieshout, Pascal

    2015-03-01

    Visual and auditory systems interact at both cortical and subcortical levels. Studies suggest a highly context-specific cross-modal modulation of the auditory system by the visual system. The present study builds on this work by sampling data from 17 young healthy adults to test whether visual speech stimuli evoke different responses in the auditory efferent system compared to visual non-speech stimuli. The descending cortical influences on medial olivocochlear (MOC) activity were indirectly assessed by examining the effects of contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) at 1, 2, 3 and 4 kHz under three conditions: (a) in the absence of any contralateral noise (Baseline), (b) contralateral noise + observing facial speech gestures related to productions of vowels /a/ and /u/ and (c) contralateral noise + observing facial non-speech gestures related to smiling and frowning. The results are based on 7 individuals whose data met strict recording criteria and indicated a significant difference in TEOAE suppression between observing speech gestures relative to the non-speech gestures, but only at the 1 kHz frequency. These results suggest that observing a speech gesture compared to a non-speech gesture may trigger a difference in MOC activity, possibly to enhance peripheral neural encoding. If such findings can be reproduced in future research, sensory perception models and theories positing the downstream convergence of unisensory streams of information in the cortex may need to be revised.

  15. Aging-induced Seizure-related Changes to the Hippocampal Mossy Fiber Pathway in Forebrain Specific BDNF Overexpressing Mice.

    Science.gov (United States)

    Weidner, Kate L; Goodman, Jeffrey H; Chadman, Kathryn K; McCloskey, Daniel P

    2011-08-01

    Aging confers an increased risk for developing seizure activity, especially within brain regions that mediate learning and synaptic plasticity. Brain derived neurotrophic factor (BDNF) is a member of the neurotrophin family that has an important role in regulating growth and development of the nervous system. BDNF is upregulated after pharmacological seizure induction and this upregulation contributes to enhanced excitability of the hippocampal mossy fiber-CA3 pathway, which is accompanied by neuropeptide Y (NPY) upregulation. Mice overexpressing a BDNF transgene in forebrain neurons provide an avenue for understanding the role of neurotrophic support in the aged hippocampus. In this study BDNF transgenic (TG) mice were utilized to determine whether increased BDNF expression through genetic manipulation resulted in age-related changes in hippocampal excitability and NPY expression. Spontaneous behavioral seizures were observed in TG mice, but not WT mice, past 5 months of age and the severity of behavioral seizures increased with age. Electrophysiological investigation of hippocampal CA3 activity indicated that slices from aged TG mice (86%), but not age-matched WT mice, or young TG mice, showed epileptiform activity in response to either repeated paired pulse or high frequency (tetanic) stimulation. Electrophysiological results were supported by the observation of robust ectopic NPY immunoreactivity in hippocampal mossy fibers of most aged TG mice (57%), which was absent in age-matched WT mice and young TG mice. The results from this study indicate that forebrain restricted BDNF overexpression produces age-related changes in hyperexcitability and NPY immunoreactivity in mossy fiber-CA3 pathway. Together, these data suggest that the capability for BDNF to promote epileptogenesis is maintained, and may be enhanced, in the aging hippocampus.

  16. Partial Epilepsy with Auditory Features

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-07-01

    Full Text Available The clinical characteristics of 53 sporadic (S cases of idiopathic partial epilepsy with auditory features (IPEAF were analyzed and compared to previously reported familial (F cases of autosomal dominant partial epilepsy with auditory features (ADPEAF in a study at the University of Bologna, Italy.

  17. Word Recognition in Auditory Cortex

    Science.gov (United States)

    DeWitt, Iain D. J.

    2013-01-01

    Although spoken word recognition is more fundamental to human communication than text recognition, knowledge of word-processing in auditory cortex is comparatively impoverished. This dissertation synthesizes current models of auditory cortex, models of cortical pattern recognition, models of single-word reading, results in phonetics and results in…

  18. Midbrain auditory selectivity to natural sounds.

    Science.gov (United States)

    Wohlgemuth, Melville J; Moss, Cynthia F

    2016-03-01

    This study investigated auditory stimulus selectivity in the midbrain superior colliculus (SC) of the echolocating bat, an animal that relies on hearing to guide its orienting behaviors. Multichannel, single-unit recordings were taken across laminae of the midbrain SC of the awake, passively listening big brown bat, Eptesicus fuscus. Species-specific frequency-modulated (FM) echolocation sound sequences with dynamic spectrotemporal features served as acoustic stimuli along with artificial sound sequences matched in bandwidth, amplitude, and duration but differing in spectrotemporal structure. Neurons in dorsal sensory regions of the bat SC responded selectively to elements within the FM sound sequences, whereas neurons in ventral sensorimotor regions showed broad response profiles to natural and artificial stimuli. Moreover, a generalized linear model (GLM) constructed on responses in the dorsal SC to artificial linear FM stimuli failed to predict responses to natural sounds and vice versa, but the GLM produced accurate response predictions in ventral SC neurons. This result suggests that auditory selectivity in the dorsal extent of the bat SC arises through nonlinear mechanisms, which extract species-specific sensory information. Importantly, auditory selectivity appeared only in responses to stimuli containing the natural statistics of acoustic signals used by the bat for spatial orientation-sonar vocalizations-offering support for the hypothesis that sensory selectivity enables rapid species-specific orienting behaviors. The results of this study are the first, to our knowledge, to show auditory spectrotemporal selectivity to natural stimuli in SC neurons and serve to inform a more general understanding of mechanisms guiding sensory selectivity for natural, goal-directed orienting behaviors.

  19. 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

  20. Tonotopic organization of human auditory association cortex.

    Science.gov (United States)

    Cansino, S; Williamson, S J; Karron, D

    1994-11-07

    Neuromagnetic studies of responses in human auditory association cortex for tone burst stimuli provide evidence for a tonotopic organization. The magnetic source image for the 100 ms component evoked by the onset of a tone is qualitatively similar to that of primary cortex, with responses lying deeper beneath the scalp for progressively higher tone frequencies. However, the tonotopic sequence of association cortex in three subjects is found largely within the superior temporal sulcus, although in the right hemisphere of one subject some sources may be closer to the inferior temporal sulcus. The locus of responses for individual subjects suggests a progression across the cortical surface that is approximately proportional to the logarithm of the tone frequency, as observed previously for primary cortex, with the span of 10 mm for each decade in frequency being comparable for the two areas.

  1. Peripheral Auditory Mechanisms

    CERN Document Server

    Hall, J; Hubbard, A; Neely, S; Tubis, A

    1986-01-01

    How weIl can we model experimental observations of the peripheral auditory system'? What theoretical predictions can we make that might be tested'? It was with these questions in mind that we organized the 1985 Mechanics of Hearing Workshop, to bring together auditory researchers to compare models with experimental observations. Tbe workshop forum was inspired by the very successful 1983 Mechanics of Hearing Workshop in Delft [1]. Boston University was chosen as the site of our meeting because of the Boston area's role as a center for hearing research in this country. We made a special effort at this meeting to attract students from around the world, because without students this field will not progress. Financial support for the workshop was provided in part by grant BNS- 8412878 from the National Science Foundation. Modeling is a traditional strategy in science and plays an important role in the scientific method. Models are the bridge between theory and experiment. Tbey test the assumptions made in experim...

  2. Cortical oscillations in auditory perception and speech: evidence for two temporal windows in human auditory cortex

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    Huan eLuo

    2012-05-01

    Full Text Available Natural sounds, including vocal communication sounds, contain critical information at multiple time scales. Two essential temporal modulation rates in speech have been argued to be in the low gamma band (~20-80 ms duration information and the theta band (~150-300 ms, corresponding to segmental and syllabic modulation rates, respectively. On one hypothesis, auditory cortex implements temporal integration using time constants closely related to these values. The neural correlates of a proposed dual temporal window mechanism in human auditory cortex remain poorly understood. We recorded MEG responses from participants listening to non-speech auditory stimuli with different temporal structures, created by concatenating frequency-modulated segments of varied segment durations. We show that these non-speech stimuli with temporal structure matching speech-relevant scales (~25 ms and ~200 ms elicit reliable phase tracking in the corresponding associated oscillatory frequencies (low gamma and theta bands. In contrast, stimuli with non-matching temporal structure do not. Furthermore, the topography of theta band phase tracking shows rightward lateralization while gamma band phase tracking occurs bilaterally. The results support the hypothesis that there exists multi-time resolution processing in cortex on discontinuous scales and provide evidence for an asymmetric organization of temporal analysis (asymmetrical sampling in time, AST. The data argue for a macroscopic-level neural mechanism underlying multi-time resolution processing: the sliding and resetting of intrinsic temporal windows on privileged time scales.

  3. Sustained selective attention to competing amplitude-modulations in human auditory cortex.

    Science.gov (United States)

    Riecke, Lars; Scharke, Wolfgang; Valente, Giancarlo; Gutschalk, Alexander

    2014-01-01

    Auditory selective attention plays an essential role for identifying sounds of interest in a scene, but the neural underpinnings are still incompletely understood. Recent findings demonstrate that neural activity that is time-locked to a particular amplitude-modulation (AM) is enhanced in the auditory cortex when the modulated stream of sounds is selectively attended to under sensory competition with other streams. However, the target sounds used in the previous studies differed not only in their AM, but also in other sound features, such as carrier frequency or location. Thus, it remains uncertain whether the observed enhancements reflect AM-selective attention. The present study aims at dissociating the effect of AM frequency on response enhancement in auditory cortex by using an ongoing auditory stimulus that contains two competing targets differing exclusively in their AM frequency. Electroencephalography results showed a sustained response enhancement for auditory attention compared to visual attention, but not for AM-selective attention (attended AM frequency vs. ignored AM frequency). In contrast, the response to the ignored AM frequency was enhanced, although a brief trend toward response enhancement occurred during the initial 15 s. Together with the previous findings, these observations indicate that selective enhancement of attended AMs in auditory cortex is adaptive under sustained AM-selective attention. This finding has implications for our understanding of cortical mechanisms for feature-based attentional gain control.

  4. Musical experience, auditory perception and reading-related skills in children.

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    Karen Banai

    Full Text Available BACKGROUND: The relationships between auditory processing and reading-related skills remain poorly understood despite intensive research. Here we focus on the potential role of musical experience as a confounding factor. Specifically we ask whether the pattern of correlations between auditory and reading related skills differ between children with different amounts of musical experience. METHODOLOGY/PRINCIPAL FINDINGS: Third grade children with various degrees of musical experience were tested on a battery of auditory processing and reading related tasks. Very poor auditory thresholds and poor memory skills were abundant only among children with no musical education. In this population, indices of auditory processing (frequency and interval discrimination thresholds were significantly correlated with and accounted for up to 13% of the variance in reading related skills. Among children with more than one year of musical training, auditory processing indices were better, yet reading related skills were not correlated with them. A potential interpretation for the reduction in the correlations might be that auditory and reading-related skills improve at different rates as a function of musical training. CONCLUSIONS/SIGNIFICANCE: Participants' previous musical training, which is typically ignored in studies assessing the relations between auditory and reading related skills, should be considered. Very poor auditory and memory skills are rare among children with even a short period of musical training, suggesting musical training could have an impact on both. The lack of correlation in the musically trained population suggests that a short period of musical training does not enhance reading related skills of individuals with within-normal auditory processing skills. Further studies are required to determine whether the associations between musical training, auditory processing and memory are indeed causal or whether children with poor auditory and

  5. Using Facebook to Reach People Who Experience Auditory Hallucinations

    Science.gov (United States)

    Brian, Rachel Marie; Ben-Zeev, Dror

    2016-01-01

    Background Auditory hallucinations (eg, hearing voices) are relatively common and underreported false sensory experiences that may produce distress and impairment. A large proportion of those who experience auditory hallucinations go unidentified and untreated. Traditional engagement methods oftentimes fall short in reaching the diverse population of people who experience auditory hallucinations. Objective The objective of this proof-of-concept study was to examine the viability of leveraging Web-based social media as a method of engaging people who experience auditory hallucinations and to evaluate their attitudes toward using social media platforms as a resource for Web-based support and technology-based treatment. Methods We used Facebook advertisements to recruit individuals who experience auditory hallucinations to complete an 18-item Web-based survey focused on issues related to auditory hallucinations and technology use in American adults. We systematically tested multiple elements of the advertisement and survey layout including image selection, survey pagination, question ordering, and advertising targeting strategy. Each element was evaluated sequentially and the most cost-effective strategy was implemented in the subsequent steps, eventually deriving an optimized approach. Three open-ended question responses were analyzed using conventional inductive content analysis. Coded responses were quantified into binary codes, and frequencies were then calculated. Results Recruitment netted N=264 total sample over a 6-week period. Ninety-seven participants fully completed all measures at a total cost of $8.14 per participant across testing phases. Systematic adjustments to advertisement design, survey layout, and targeting strategies improved data quality and cost efficiency. People were willing to provide information on what triggered their auditory hallucinations along with strategies they use to cope, as well as provide suggestions to others who experience

  6. Neural Representation of Concurrent Vowels in Macaque Primary Auditory Cortex.

    Science.gov (United States)

    Fishman, Yonatan I; Micheyl, Christophe; Steinschneider, Mitchell

    2016-01-01

    Successful speech perception in real-world environments requires that the auditory system segregate competing voices that overlap in frequency and time into separate streams. Vowels are major constituents of speech and are comprised of frequencies (harmonics) that are integer multiples of a common fundamental frequency (F0). The pitch and identity of a vowel are determined by its F0 and spectral envelope (formant structure), respectively. When two spectrally overlapping vowels differing in F0 are presented concurrently, they can be readily perceived as two separate "auditory objects" with pitches at their respective F0s. A difference in pitch between two simultaneous vowels provides a powerful cue for their segregation, which in turn, facilitates their individual identification. The neural mechanisms underlying the segregation of concurrent vowels based on pitch differences are poorly understood. Here, we examine neural population responses in macaque primary auditory cortex (A1) to single and double concurrent vowels (/a/ and /i/) that differ in F0 such that they are heard as two separate auditory objects with distinct pitches. We find that neural population responses in A1 can resolve, via a rate-place code, lower harmonics of both single and double concurrent vowels. Furthermore, we show that the formant structures, and hence the identities, of single vowels can be reliably recovered from the neural representation of double concurrent vowels. We conclude that A1 contains sufficient spectral information to enable concurrent vowel segregation and identification by downstream cortical areas.

  7. Auditory Memory deficit in Elderly People with Hearing Loss

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    Zahra Shahidipour

    2013-06-01

    Full Text Available Introduction: Hearing loss is one of the most common problems in elderly people. Functional side effects of hearing loss are various. Due to the fact that hearing loss is the common impairment in elderly people; the importance of its possible effects on auditory memory is undeniable. This study aims to focus on the hearing loss effects on auditory memory.   Materials and Methods: Dichotic Auditory Memory Test (DVMT was performed on 47 elderly people, aged 60 to 80; that were divided in two groups, the first group consisted of elderly people with hearing range of 24 normal and the second one consisted of 23 elderly people with bilateral symmetrical ranged from mild to moderate Sensorineural hearing loss in the high frequency due to aging in both genders.   Results: Significant difference was observed in DVMT between elderly people with normal hearing and those with hearing loss (P

  8. 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...

  9. Auditory short-term memory in the primate auditory cortex.

    Science.gov (United States)

    Scott, Brian H; Mishkin, Mortimer

    2016-06-01

    Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory.

  10. Modulation of auditory brainstem responses by serotonin and specific serotonin receptors.

    Science.gov (United States)

    Papesh, Melissa A; Hurley, Laura M

    2016-02-01

    The neuromodulator serotonin is found throughout the auditory system from the cochlea to the cortex. Although effects of serotonin have been reported at the level of single neurons in many brainstem nuclei, how these effects correspond to more integrated measures of auditory processing has not been well-explored. In the present study, we aimed to characterize the effects of serotonin on far-field auditory brainstem responses (ABR) across a wide range of stimulus frequencies and intensities. Using a mouse model, we investigated the consequences of systemic serotonin depletion, as well as the selective stimulation and suppression of the 5-HT1 and 5-HT2 receptors, on ABR latency and amplitude. Stimuli included tone pips spanning four octaves presented over a forty dB range. Depletion of serotonin reduced the ABR latencies in Wave II and later waves, suggesting that serotonergic effects occur as early as the cochlear nucleus. Further, agonists and antagonists of specific serotonergic receptors had different profiles of effects on ABR latencies and amplitudes across waves and frequencies, suggestive of distinct effects of these agents on auditory processing. Finally, most serotonergic effects were more pronounced at lower ABR frequencies, suggesting larger or more directional modulation of low-frequency processing. This is the first study to describe the effects of serotonin on ABR responses across a wide range of stimulus frequencies and amplitudes, and it presents an important step in understanding how serotonergic modulation of auditory brainstem processing may contribute to modulation of auditory perception.

  11. Effects of heavy ions on rabbit tissues: damage to the forebrain

    Energy Technology Data Exchange (ETDEWEB)

    Cox, A.B.; Keng, P.C.; Lee, A.C.; Lett, J.T. (Colorado State Univ., Fort Collins (USA). Dept. of Radiology and Radiation Biology)

    1982-10-01

    As part of a study of progressive radiation effects in normal tissues, the forebrains of New Zealand white rabbits (Oryctolagus cuniculus) (about 6 weeks old) were irradiated locally with single acute doses of /sup 60/Co ..gamma..-photons (LETsub(infinity)=0.3 keV/..mu..m), Ne ions (LETsub(infinity)=35+-3 keV/..mu..m) or Ar ions (LETsub(infinity)=90+-5 keV/..mu..m). Other rabbits received fractionated doses of /sup 60/Co ..gamma..-photons according to a standard radiotherapeutic protocol. Irradiated rabbits and appropriately aged controls were sacrificed at selected intervals, and whole sagittal sections of their brains were examined for pathological changes. Forebrain damage was scored with subjective indices based on histological differences between the anterior (irradiated) and posterior (unirradiated) regions of the brain. Those indices ranged from zero (no apparent damage) to five (severe infarctions, etc.). At intermediate levels of forebrain damage, the relative biological effectiveness (r.b.e.) of each heavy ion was similar to that found for alopecia and cataractogenesis, and the early expression of the damage was also accelerated as the LETsub(infinity) increased. Late deterioration of the forebrain appeared also to be accelerated by increasing LETsub(infinity), although its accurate quantification was not possible because other priorities in the overall experimental design limited systematic sacrifice of the animals.

  12. Fgf19 regulated by Hh signaling is required for zebrafish forebrain development.

    Science.gov (United States)

    Miyake, Ayumi; Nakayama, Yoshiaki; Konishi, Morichika; Itoh, Nobuyuki

    2005-12-01

    Fibroblast growth factor (Fgf) signaling plays important roles in brain development. Fgf3 and Fgf8 are crucial for the formation of the forebrain and hindbrain. Fgf8 is also required for the midbrain to form. Here, we identified zebrafish Fgf19 and examined its roles in brain development by knocking down Fgf19 function. We found that Fgf19 expressed in the forebrain, midbrain and hindbrain was involved in cell proliferation and cell survival during embryonic brain development. Fgf19 was also essential for development of the ventral telencephalon and diencephalon. Regional specification is linked to cell type specification. Fgf19 was also essential for the specification of gamma-aminobutyric acid (GABA)ergic interneurons and oligodendrocytes generated in the ventral telencephalon and diencephalon. The cross talk between Fgf and Hh signaling is critical for brain development. In the forebrain, Fgf19 expression was down-regulated on inhibition of Hh but not of Fgf3/Fgf8, and overexpression of Fgf19 rescued partially the phenotype on inhibition of Hh. The present findings indicate that Fgf19 signaling is crucial for forebrain development by interacting with Hh and provide new insights into the roles of Fgf signaling in brain development.

  13. Spatial organization of tettigoniid auditory receptors: insights from neuronal tracing.

    Science.gov (United States)

    Strauß, Johannes; Lehmann, Gerlind U C; Lehmann, Arne W; Lakes-Harlan, Reinhard

    2012-11-01

    The auditory sense organ of Tettigoniidae (Insecta, Orthoptera) is located in the foreleg tibia and consists of scolopidial sensilla which form a row termed crista acustica. The crista acustica is associated with the tympana and the auditory trachea. This ear is a highly ordered, tonotopic sensory system. As the neuroanatomy of the crista acustica has been documented for several species, the most distal somata and dendrites of receptor neurons have occasionally been described as forming an alternating or double row. We investigate the spatial arrangement of receptor cell bodies and dendrites by retrograde tracing with cobalt chloride solution. In six tettigoniid species studied, distal receptor neurons are consistently arranged in double-rows of somata rather than a linear sequence. This arrangement of neurons is shown to affect 30-50% of the overall auditory receptors. No strict correlation of somata positions between the anterio-posterior and dorso-ventral axis was evident within the distal crista acustica. Dendrites of distal receptors occasionally also occur in a double row or are even massed without clear order. Thus, a substantial part of auditory receptors can deviate from a strictly straight organization into a more complex morphology. The linear organization of dendrites is not a morphological criterion that allows hearing organs to be distinguished from nonhearing sense organs serially homologous to ears in all species. Both the crowded arrangement of receptor somata and dendrites may result from functional constraints relating to frequency discrimination, or from developmental constraints of auditory morphogenesis in postembryonic development.

  14. Modeling of Auditory Neuron Response Thresholds with Cochlear Implants

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    Frederic Venail

    2015-01-01

    Full Text Available The quality of the prosthetic-neural interface is a critical point for cochlear implant efficiency. It depends not only on technical and anatomical factors such as electrode position into the cochlea (depth and scalar placement, electrode impedance, and distance between the electrode and the stimulated auditory neurons, but also on the number of functional auditory neurons. The efficiency of electrical stimulation can be assessed by the measurement of e-CAP in cochlear implant users. In the present study, we modeled the activation of auditory neurons in cochlear implant recipients (nucleus device. The electrical response, measured using auto-NRT (neural responses telemetry algorithm, has been analyzed using multivariate regression with cubic splines in order to take into account the variations of insertion depth of electrodes amongst subjects as well as the other technical and anatomical factors listed above. NRT thresholds depend on the electrode squared impedance (β = −0.11 ± 0.02, P<0.01, the scalar placement of the electrodes (β = −8.50 ± 1.97, P<0.01, and the depth of insertion calculated as the characteristic frequency of auditory neurons (CNF. Distribution of NRT residues according to CNF could provide a proxy of auditory neurons functioning in implanted cochleas.

  15. Modeling of Auditory Neuron Response Thresholds with Cochlear Implants.

    Science.gov (United States)

    Venail, Frederic; Mura, Thibault; Akkari, Mohamed; Mathiolon, Caroline; Menjot de Champfleur, Sophie; Piron, Jean Pierre; Sicard, Marielle; Sterkers-Artieres, Françoise; Mondain, Michel; Uziel, Alain

    2015-01-01

    The quality of the prosthetic-neural interface is a critical point for cochlear implant efficiency. It depends not only on technical and anatomical factors such as electrode position into the cochlea (depth and scalar placement), electrode impedance, and distance between the electrode and the stimulated auditory neurons, but also on the number of functional auditory neurons. The efficiency of electrical stimulation can be assessed by the measurement of e-CAP in cochlear implant users. In the present study, we modeled the activation of auditory neurons in cochlear implant recipients (nucleus device). The electrical response, measured using auto-NRT (neural responses telemetry) algorithm, has been analyzed using multivariate regression with cubic splines in order to take into account the variations of insertion depth of electrodes amongst subjects as well as the other technical and anatomical factors listed above. NRT thresholds depend on the electrode squared impedance (β = -0.11 ± 0.02, P < 0.01), the scalar placement of the electrodes (β = -8.50 ± 1.97, P < 0.01), and the depth of insertion calculated as the characteristic frequency of auditory neurons (CNF). Distribution of NRT residues according to CNF could provide a proxy of auditory neurons functioning in implanted cochleas.

  16. Auditory Neuropathy - A Case of Auditory Neuropathy after Hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    Maliheh Mazaher Yazdi

    2007-12-01

    Full Text Available Background and Aim: Auditory neuropathy is an hearing disorder in which peripheral hearing is normal, but the eighth nerve and brainstem are abnormal. By clinical definition, patient with this disorder have normal OAE, but exhibit an absent or severely abnormal ABR. Auditory neuropathy was first reported in the late 1970s as different methods could identify discrepancy between absent ABR and present hearing threshold. Speech understanding difficulties are worse than can be predicted from other tests of hearing function. Auditory neuropathy may also affect vestibular function. Case Report: This article presents electrophysiological and behavioral data from a case of auditory neuropathy in a child with normal hearing after bilirubinemia in a 5 years follow-up. Audiological findings demonstrate remarkable changes after multidisciplinary rehabilitation. Conclusion: auditory neuropathy may involve damage to the inner hair cells-specialized sensory cells in the inner ear that transmit information about sound through the nervous system to the brain. Other causes may include faulty connections between the inner hair cells and the nerve leading from the inner ear to the brain or damage to the nerve itself. People with auditory neuropathy have OAEs response but absent ABR and hearing loss threshold that can be permanent, get worse or get better.

  17. Neural interactions in unilateral colliculus and between bilateral colliculi modulate auditory signal processing

    Science.gov (United States)

    Mei, Hui-Xian; Cheng, Liang; Chen, Qi-Cai

    2013-01-01

    In the auditory pathway, the inferior colliculus (IC) is a major center for temporal and spectral integration of auditory information. There are widespread neural interactions in unilateral (one) IC and between bilateral (two) ICs that could modulate auditory signal processing such as the amplitude and frequency selectivity of IC neurons. These neural interactions are either inhibitory or excitatory, and are mostly mediated by γ-aminobutyric acid (GABA) and glutamate, respectively. However, the majority of interactions are inhibitory while excitatory interactions are in the minority. Such unbalanced properties between excitatory and inhibitory projections have an important role in the formation of unilateral auditory dominance and sound location, and the neural interaction in one IC and between two ICs provide an adjustable and plastic modulation pattern for auditory signal processing. PMID:23626523

  18. Neural interactions in unilateral colliculus and between bilateral colliculi modulate auditory signal processing.

    Science.gov (United States)

    Mei, Hui-Xian; Cheng, Liang; Chen, Qi-Cai

    2013-01-01

    In the auditory pathway, the inferior colliculus (IC) is a major center for temporal and spectral integration of auditory information. There are widespread neural interactions in unilateral (one) IC and between bilateral (two) ICs that could modulate auditory signal processing such as the amplitude and frequency selectivity of IC neurons. These neural interactions are either inhibitory or excitatory, and are mostly mediated by γ-aminobutyric acid (GABA) and glutamate, respectively. However, the majority of interactions are inhibitory while excitatory interactions are in the minority. Such unbalanced properties between excitatory and inhibitory projections have an important role in the formation of unilateral auditory dominance and sound location, and the neural interaction in one IC and between two ICs provide an adjustable and plastic modulation pattern for auditory signal processing.

  19. Receptive field plasticity of neurons in rat auditory cortex

    Institute of Scientific and Technical Information of China (English)

    YANG Wenwei; GAO Lixia; SUN Xinde

    2004-01-01

    Using conventional electrophysiological technique, we investigated the plasticity of the frequency receptive fields (RF) of auditory cortex (AC) neurons in rats. In the AC, when the frequency difference between conditioning stimulus frequency (CSF) and the best frequency (BF) was in the range of 1-4 kHz, the frequency RF of AC neurons shifted. The smaller the differences between CSF and BF, the higher the probability of the RF shift and the greater the degree of the RF shift. To some extent, the plasticity of RF was dependent on the duration of the session of conditioning stimulus (CS). When the frequency difference between CSF and BF was bigger, the duration of the CS session needed to induce the plasticity was longer. The recovery time course of the frequency RF showed opposite changes after CS cessation.The RF shift could be induced by the frequency that was either higher or lower than the control BF, demonstrating no clear directional preference. The frequency RF of some neurons showed bidirectional shift, and the RF of other neurons showed single directional shift. The results suggest that the frequency RF plasticity of AC neurons could be considered as an ideal model for studying plasticity mechanism. The present study also provides important evidence for further study of learning and memory in auditory system.

  20. Auditory Processing Disorder (For Parents)

    Science.gov (United States)

    ... CAPD often have trouble maintaining attention, although health, motivation, and attitude also can play a role. Auditory ... programs. Several computer-assisted programs are geared toward children with APD. They mainly help the brain do ...

  1. An Experimental Investigation of the Effect of Altered Auditory Feedback on the Conversational Speech of Adults Who Stutter

    Science.gov (United States)

    Lincoln, Michelle; Packman, Ann; Onslow, Mark; Jones, Mark

    2010-01-01

    Purpose: To investigate the impact on percentage of syllables stuttered of various durations of delayed auditory feedback (DAF), levels of frequency-altered feedback (FAF), and masking auditory feedback (MAF) during conversational speech. Method: Eleven adults who stuttered produced 10-min conversational speech samples during a control condition…

  2. Attentional modulation of auditory steady-state responses.

    Directory of Open Access Journals (Sweden)

    Yatin Mahajan

    Full Text Available Auditory selective attention enables task-relevant auditory events to be enhanced and irrelevant ones suppressed. In the present study we used a frequency tagging paradigm to investigate the effects of attention on auditory steady state responses (ASSR. The ASSR was elicited by simultaneously presenting two different streams of white noise, amplitude modulated at either 16 and 23.5 Hz or 32.5 and 40 Hz. The two different frequencies were presented to each ear and participants were instructed to selectively attend to one ear or the other (confirmed by behavioral evidence. The results revealed that modulation of ASSR by selective attention depended on the modulation frequencies used and whether the activation was contralateral or ipsilateral. Attention enhanced the ASSR for contralateral activation from either ear for 16 Hz and suppressed the ASSR for ipsilateral activation for 16 Hz and 23.5 Hz. For modulation frequencies of 32.5 or 40 Hz attention did not affect the ASSR. We propose that the pattern of enhancement and inhibition may be due to binaural suppressive effects on ipsilateral stimulation and the dominance of contralateral hemisphere during dichotic listening. In addition to the influence of cortical processing asymmetries, these results may also reflect a bias towards inhibitory ipsilateral and excitatory contralateral activation present at the level of inferior colliculus. That the effect of attention was clearest for the lower modulation frequencies suggests that such effects are likely mediated by cortical brain structures or by those in close proximity to cortex.

  3. Auditory and Visual Electrophysiology of Deaf Children with Cochlear Implants: Implications for Cross-modal Plasticity.

    Science.gov (United States)

    Corina, David P; Blau, Shane; LaMarr, Todd; Lawyer, Laurel A; Coffey-Corina, Sharon

    2017-01-01

    Deaf children who receive a cochlear implant early in life and engage in intensive oral/aural therapy often make great strides in spoken language acquisition. However, despite clinicians' best efforts, there is a great deal of variability in language outcomes. One concern is that cortical regions which normally support auditory processing may become reorganized for visual function, leaving fewer available resources for auditory language acquisition. The conditions under which these changes occur are not well understood, but we may begin investigating this phenomenon by looking for interactions between auditory and visual evoked cortical potentials in deaf children. If children with abnormal auditory responses show increased sensitivity to visual stimuli, this may indicate the presence of maladaptive cortical plasticity. We recorded evoked potentials, using both auditory and visual paradigms, from 25 typical hearing children and 26 deaf children (ages 2-8 years) with cochlear implants. An auditory oddball paradigm was used (85% /ba/ syllables vs. 15% frequency modulated tone sweeps) to elicit an auditory P1 component. Visual evoked potentials (VEPs) were recorded during presentation of an intermittent peripheral radial checkerboard while children watched a silent cartoon, eliciting a P1-N1 response. We observed reduced auditory P1 amplitudes and a lack of latency shift associated with normative aging in our deaf sample. We also observed shorter latencies in N1 VEPs to visual stimulus offset in deaf participants. While these data demonstrate cortical changes associated with auditory deprivation, we did not find evidence for a relationship between cortical auditory evoked potentials and the VEPs. This is consistent with descriptions of intra-modal plasticity within visual systems of deaf children, but do not provide evidence for cross-modal plasticity. In addition, we note that sign language experience had no effect on deaf children's early auditory and visual ERP

  4. Auditory and Visual Electrophysiology of Deaf Children with Cochlear Implants: Implications for Cross-modal Plasticity

    Science.gov (United States)

    Corina, David P.; Blau, Shane; LaMarr, Todd; Lawyer, Laurel A.; Coffey-Corina, Sharon

    2017-01-01

    Deaf children who receive a cochlear implant early in life and engage in intensive oral/aural therapy often make great strides in spoken language acquisition. However, despite clinicians’ best efforts, there is a great deal of variability in language outcomes. One concern is that cortical regions which normally support auditory processing may become reorganized for visual function, leaving fewer available resources for auditory language acquisition. The conditions under which these changes occur are not well understood, but we may begin investigating this phenomenon by looking for interactions between auditory and visual evoked cortical potentials in deaf children. If children with abnormal auditory responses show increased sensitivity to visual stimuli, this may indicate the presence of maladaptive cortical plasticity. We recorded evoked potentials, using both auditory and visual paradigms, from 25 typical hearing children and 26 deaf children (ages 2–8 years) with cochlear implants. An auditory oddball paradigm was used (85% /ba/ syllables vs. 15% frequency modulated tone sweeps) to elicit an auditory P1 component. Visual evoked potentials (VEPs) were recorded during presentation of an intermittent peripheral radial checkerboard while children watched a silent cartoon, eliciting a P1–N1 response. We observed reduced auditory P1 amplitudes and a lack of latency shift associated with normative aging in our deaf sample. We also observed shorter latencies in N1 VEPs to visual stimulus offset in deaf participants. While these data demonstrate cortical changes associated with auditory deprivation, we did not find evidence for a relationship between cortical auditory evoked potentials and the VEPs. This is consistent with descriptions of intra-modal plasticity within visual systems of deaf children, but do not provide evidence for cross-modal plasticity. In addition, we note that sign language experience had no effect on deaf children’s early auditory and visual

  5. Background sounds contribute to spectrotemporal plasticity in primary auditory cortex.

    Science.gov (United States)

    Moucha, Raluca; Pandya, Pritesh K; Engineer, Navzer D; Rathbun, Daniel L; Kilgard, Michael P

    2005-05-01

    The mammalian auditory system evolved to extract meaningful information from complex acoustic environments. Spectrotemporal selectivity of auditory neurons provides a potential mechanism to represent natural sounds. Experience-dependent plasticity mechanisms can remodel the spectrotemporal selectivity of neurons in primary auditory cortex (A1). Electrical stimulation of the cholinergic nucleus basalis (NB) enables plasticity in A1 that parallels natural learning and is specific to acoustic features associated with NB activity. In this study, we used NB stimulation to explore how cortical networks reorganize after experience with frequency-modulated (FM) sweeps, and how background stimuli contribute to spectrotemporal plasticity in rat auditory cortex. Pairing an 8-4 kHz FM sweep with NB stimulation 300 times per day for 20 days decreased tone thresholds, frequency selectivity, and response latency of A1 neurons in the region of the tonotopic map activated by the sound. In an attempt to modify neuronal response properties across all of A1 the same NB activation was paired in a second group of rats with five downward FM sweeps, each spanning a different octave. No changes in FM selectivity or receptive field (RF) structure were observed when the neural activation was distributed across the cortical surface. However, the addition of unpaired background sweeps of different rates or direction was sufficient to alter RF characteristics across the tonotopic map in a third group of rats. These results extend earlier observations that cortical neurons can develop stimulus specific plasticity and indicate that background conditions can strongly influence cortical plasticity.

  6. You can't stop the music: reduced auditory alpha power and coupling between auditory and memory regions facilitate the illusory perception of music during noise.

    Science.gov (United States)

    Müller, Nadia; Keil, Julian; Obleser, Jonas; Schulz, Hannah; Grunwald, Thomas; Bernays, René-Ludwig; Huppertz, Hans-Jürgen; Weisz, Nathan

    2013-10-01

    Our brain has the capacity of providing an experience of hearing even in the absence of auditory stimulation. This can be seen as illusory conscious perception. While increasing evidence postulates that conscious perception requires specific brain states that systematically relate to specific patterns of oscillatory activity, the relationship between auditory illusions and oscillatory activity remains mostly unexplained. To investigate this we recorded brain activity with magnetoencephalography and collected intracranial data from epilepsy patients while participants listened to familiar as well as unknown music that was partly replaced by sections of pink noise. We hypothesized that participants have a stronger experience of hearing music throughout noise when the noise sections are embedded in familiar compared to unfamiliar music. This was supported by the behavioral results showing that participants rated the perception of music during noise as stronger when noise was presented in a familiar context. Time-frequency data show that the illusory perception of music is associated with a decrease in auditory alpha power pointing to increased auditory cortex excitability. Furthermore, the right auditory cortex is concurrently synchronized with the medial temporal lobe, putatively mediating memory aspects associated with the music illusion. We thus assume that neuronal activity in the highly excitable auditory cortex is shaped through extensive communication between the auditory cortex and the medial temporal lobe, thereby generating the illusion of hearing music during noise.

  7. Time computations in anuran auditory systems

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    Gary J Rose

    2014-05-01

    Full Text Available Temporal computations are important in the acoustic communication of anurans. In many cases, calls between closely related species are nearly identical spectrally but differ markedly in temporal structure. Depending on the species, calls can differ in pulse duration, shape and/or rate (i.e., amplitude modulation, direction and rate of frequency modulation, and overall call duration. Also, behavioral studies have shown that anurans are able to discriminate between calls that differ in temporal structure. In the peripheral auditory system, temporal information is coded primarily in the spatiotemporal patterns of activity of auditory-nerve fibers. However, major transformations in the representation of temporal information occur in the central auditory system. In this review I summarize recent advances in understanding how temporal information is represented in the anuran midbrain, with particular emphasis on mechanisms that underlie selectivity for pulse duration and pulse rate (i.e., intervals between onsets of successive pulses. Two types of neurons have been identified that show selectivity for pulse rate: long-interval cells respond well to slow pulse rates but fail to spike or respond phasically to fast pulse rates; conversely, interval-counting neurons respond to intermediate or fast pulse rates, but only after a threshold number of pulses, presented at optimal intervals, have occurred. Duration-selectivity is manifest as short-pass, band-pass or long-pass tuning. Whole-cell patch recordings, in vivo, suggest that excitation and inhibition are integrated in diverse ways to generate temporal selectivity. In many cases, activity-related enhancement or depression of excitatory or inhibitory processes appear to contribute to selective responses.

  8. Developmental evaluation of atypical auditory sampling in dyslexia: Functional and structural evidence.

    Science.gov (United States)

    Lizarazu, Mikel; Lallier, Marie; Molinaro, Nicola; Bourguignon, Mathieu; Paz-Alonso, Pedro M; Lerma-Usabiaga, Garikoitz; Carreiras, Manuel

    2015-12-01

    Whether phonological deficits in developmental dyslexia are associated with impaired neural sampling of auditory information at either syllabic- or phonemic-rates is still under debate. In addition, whereas neuroanatomical alterations in auditory regions have been documented in dyslexic readers, whether and how these structural anomalies are linked to auditory sampling and reading deficits remains poorly understood. In this study, we measured auditory neural synchronization at different frequencies corresponding to relevant phonological spectral components of speech in children and adults with and without dyslexia, using magnetoencephalography. Furthermore, structural MRI was used to estimate cortical thickness of the auditory cortex of participants. Dyslexics showed atypical brain synchronization at both syllabic (slow) and phonemic (fast) rates. Interestingly, while a left hemispheric asymmetry in cortical thickness was functionally related to a stronger left hemispheric lateralization of neural synchronization to stimuli presented at the phonemic rate in skilled readers, the same anatomical index in dyslexics was related to a stronger right hemispheric dominance for neural synchronization to syllabic-rate auditory stimuli. These data suggest that the acoustic sampling deficit in development dyslexia might be linked to an atypical specialization of the auditory cortex to both low and high frequency amplitude modulations.

  9. The role of auditory abilities in basic mechanisms of cognition in older adults

    Directory of Open Access Journals (Sweden)

    Massimo eGrassi

    2013-10-01

    Full Text Available The aim of this study was to assess age-related differences between young and older adults in auditory abilities and to investigate the relationship between auditory abilities and basic mechanisms of cognition in older adults. Although there is a certain consensus that the participant’s sensitivity to the absolute intensity of sounds (such as that measured via pure tone audiometry explains his/her cognitive performance, there is not yet much evidence that the participant’s auditory ability (i.e., the whole supra-threshold processing of sounds explains his/her cognitive performance. Twenty-eight young adults (age < 35, 26 young-old adults (65 ≤ age ≤75 and 28 old-old adults (age > 75 were presented with a set of tasks estimating several auditory abilities (i.e., frequency discrimination, intensity discrimination, duration discrimination, timbre discrimination, gap detection, amplitude modulation detection, and the absolute threshold for a 1 kHz pure tone and the participant’s working memory, cognitive inhibition, and processing speed. Results showed an age-related decline in both auditory and cognitive performance. Moreover, regression analyses showed that a subset of the auditory abilities (i.e., the ability to discriminate frequency, duration, timbre, and the ability to detect amplitude modulation explained a significant part of the variance observed in processing speed in older adults. Overall, the present results highlight the relationship between auditory abilities and basic mechanisms of cognition.

  10. Temporal coding by populations of auditory receptor neurons.

    Science.gov (United States)

    Sabourin, Patrick; Pollack, Gerald S

    2010-03-01

    Auditory receptor neurons of crickets are most sensitive to either low or high sound frequencies. Earlier work showed that the temporal coding properties of first-order auditory interneurons are matched to the temporal characteristics of natural low- and high-frequency stimuli (cricket songs and bat echolocation calls, respectively). We studied the temporal coding properties of receptor neurons and used modeling to investigate how activity within populations of low- and high-frequency receptors might contribute to the coding properties of interneurons. We confirm earlier findings that individual low-frequency-tuned receptors code stimulus temporal pattern poorly, but show that coding performance of a receptor population increases markedly with population size, due in part to low redundancy among the spike trains of different receptors. By contrast, individual high-frequency-tuned receptors code a stimulus temporal pattern fairly well and, because their spike trains are redundant, there is only a slight increase in coding performance with population size. The coding properties of low- and high-frequency receptor populations resemble those of interneurons in response to low- and high-frequency stimuli, suggesting that coding at the interneuron level is partly determined by the nature and organization of afferent input. Consistent with this, the sound-frequency-specific coding properties of an interneuron, previously demonstrated by analyzing its spike train, are also apparent in the subthreshold fluctuations in membrane potential that are generated by synaptic input from receptor neurons.

  11. Brain Barriers and a Subpopulation of Astroglial Progenitors of Developing Human Forebrain Are Immunostained for the Glycoprotein YKL-40

    DEFF Research Database (Denmark)

    Bjørnbak, Camilla; Brøchner, Christian B; Larsen, Lars A

    2014-01-01

    YKL-40, a glycoprotein involved in cell differentiation, has been associated with neurodevelopmental disorders, angiogenesis, neuroinflammation and glioblastomas. We evaluated YKL-40 protein distribution in the early human forebrain using double-labeling immunofluorescence and immunohistochemistry...

  12. Development of glucocorticoid receptor regulation in the rat forebrain: Implications for adverse effects of glucocorticoids in preterm infants

    Science.gov (United States)

    Glucocorticoids are the consensus treatment to avoid respiratory distress in preterm infants but there is accumulating evidence that these agents evoke long-term neurobehavioral deficits. Earlier, we showed that the developing rat forebrain is far more sensitive to glucocorticoi...

  13. Auditory discrimination of force of impact.

    Science.gov (United States)

    Lutfi, Robert A; Liu, Ching-Ju; Stoelinga, Christophe N J

    2011-04-01

    The auditory discrimination of force of impact was measured for three groups of listeners using sounds synthesized according to first-order equations of motion for the homogenous, isotropic bar [Morse and Ingard (1968). Theoretical Acoustics pp. 175-191]. The three groups were professional percussionists, nonmusicians, and individuals recruited from the general population without regard to musical background. In the two-interval, forced-choice procedure, listeners chose the sound corresponding to the greater force of impact as the length of the bar varied from one presentation to the next. From the equations of motion, a maximum-likelihood test for the task was determined to be of the form Δlog A + αΔ log f > 0, where A and f are the amplitude and frequency of any one partial and α = 0.5. Relative decision weights on Δ log f were obtained from the trial-by-trial responses of listeners and compared to α. Percussionists generally outperformed the other groups; however, the obtained decision weights of all listeners deviated significantly from α and showed variability within groups far in excess of the variability associated with replication. Providing correct feedback after each trial had little effect on the decision weights. The variability in these measures was comparable to that seen in studies involving the auditory discrimination of other source attributes.

  14. Different auditory feedback control for echolocation and communication in horseshoe bats.

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    Ying Liu

    Full Text Available Auditory feedback from the animal's own voice is essential during bat echolocation: to optimize signal detection, bats continuously adjust various call parameters in response to changing echo signals. Auditory feedback seems also necessary for controlling many bat communication calls, although it remains unclear how auditory feedback control differs in echolocation and communication. We tackled this question by analyzing echolocation and communication in greater horseshoe bats, whose echolocation pulses are dominated by a constant frequency component that matches the frequency range they hear best. To maintain echoes within this "auditory fovea", horseshoe bats constantly adjust their echolocation call frequency depending on the frequency of the returning echo signal. This Doppler-shift compensation (DSC behavior represents one of the most precise forms of sensory-motor feedback known. We examined the variability of echolocation pulses emitted at rest (resting frequencies, RFs and one type of communication signal which resembles an echolocation pulse but is much shorter (short constant frequency communication calls, SCFs and produced only during social interactions. We found that while RFs varied from day to day, corroborating earlier studies in other constant frequency bats, SCF-frequencies remained unchanged. In addition, RFs overlapped for some bats whereas SCF-frequencies were always distinctly different. This indicates that auditory feedback during echolocation changed with varying RFs but remained constant or may have been absent during emission of SCF calls for communication. This fundamentally different feedback mechanism for echolocation and communication may have enabled these bats to use SCF calls for individual recognition whereas they adjusted RF calls to accommodate the daily shifts of their auditory fovea.

  15. Rabbit Forebrain cholinergic system: Morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus

    OpenAIRE

    C. Varga; Hartig, W.; Grosche, J.; Luiten, PGM; Seeger, J.; K. Brauer; Harkany, T.; Härtig, Wolfgang; Keijser, Jan N.

    2003-01-01

    Although the rabbit brain, in particular the basal forebrain cholinergic system, has become a common model for neuropathological changes associated with Alzheimer's disease, detailed neuroanatomical studies on the morphological organization of basal forebrain cholinergic nuclei and on their output pathways are still awaited. Therefore, we performed quantitative choline acetyltransferase (ChAT) immunocytochemistry to localize major cholinergic nuclei and to determine the number of respective c...

  16. Forebrain-Specific Loss of BMPRII in Mice Reduces Anxiety and Increases Object Exploration.

    Directory of Open Access Journals (Sweden)

    Zofeyah L McBrayer

    Full Text Available To investigate the role of Bone Morphogenic Protein Receptor Type II (BMPRII in learning, memory, and exploratory behavior in mice, a tissue-specific knockout of BMPRII in the post-natal hippocampus and forebrain was generated. We found that BMPRII mutant mice had normal spatial learning and memory in the Morris water maze, but showed significantly reduced swimming speeds with increased floating behavior. Further analysis using the Porsolt Swim Test to investigate behavioral despair did not reveal any differences in immobility between mutants and controls. In the Elevated Plus Maze, BMPRII mutants and Smad4 mutants showed reduced anxiety, while in exploratory tests, BMPRII mutants showed more interest in object exploration. These results suggest that loss of BMPRII in the mouse hippocampus and forebrain does not disrupt spatial learning and memory encoding, but instead impacts exploratory and anxiety-related behaviors.

  17. Brain-derived neurotrophic factor (BDNF) overexpression in the forebrain results in learning and memory impairments.

    Science.gov (United States)

    Cunha, Carla; Angelucci, Andrea; D'Antoni, Angela; Dobrossy, Mate D; Dunnett, Stephen B; Berardi, Nicoletta; Brambilla, Riccardo

    2009-03-01

    In this study we analyzed the effect on behavior of a chronic exposure to brain-derived neurotrophic factor (BDNF), by analysing a mouse line overexpressing BDNF under the alphaCaMKII promoter, which drives the transgene expression exclusively to principal neurons of the forebrain. BDNF transgenic mice and their WT littermates were examined with a battery of behavioral tests, in order to evaluate motor coordination, learning, short and long-term memory formation. Our results demonstrate that chronic BDNF overexpression in the central nervous system (CNS) causes learning deficits and short-term memory impairments, both in spatial and instrumental learning tasks. This observation suggests that a widespread increase in BDNF in forebrain networks may result in adverse effects on learning and memory formation.

  18. Clonally Related Forebrain Interneurons Disperse Broadly across Both Functional Areas and Structural Boundaries.

    Science.gov (United States)

    Mayer, Christian; Jaglin, Xavier H; Cobbs, Lucy V; Bandler, Rachel C; Streicher, Carmen; Cepko, Constance L; Hippenmeyer, Simon; Fishell, Gord

    2015-09-02

    The medial ganglionic eminence (MGE) gives rise to the majority of mouse forebrain interneurons. Here, we examine the lineage relationship among MGE-derived interneurons using a replication-defective retroviral library containing a highly diverse set of DNA barcodes. Recovering the barcodes from the mature progeny of infected progenitor cells enabled us to unambiguously determine their respective lineal relationship. We found that clonal dispersion occurs across large areas of the brain and is not restricted by anatomical divisions. As such, sibling interneurons can populate the cortex, hippocampus striatum, and globus pallidus. The majority of interneurons appeared to be generated from asymmetric divisions of MGE progenitor cells, followed by symmetric divisions within the subventricular zone. Altogether, our findings uncover that lineage relationships do not appear to determine interneuron allocation to particular regions. As such, it is likely that clonally related interneurons have considerable flexibility as to the particular forebrain circuits to which they can contribute.

  19. Role of tissue plasminogen activator/plasmin cascade in delayed neuronal death after transient forebrain ischemia.

    Science.gov (United States)

    Takahashi, Hiroshi; Nagai, Nobuo; Urano, Tetsumei

    We studied the possible involvement of the tissue plasminogen activator (t-PA)/plasmin system on both delayed neuronal death in the hippocampus and the associated enhancement of locomotor activity in rats, after transient forebrain ischemia induced by a four-vessel occlusion (FVO). Seven days after FVO, locomotor activity was abnormally increased and, after 10 days, pyramidal cells were degraded in the CA1 region of the hippocampus. FVO increased the t-PA antigen level and its activity in the hippocampus, which peaked at 4 h. Both the enhanced locomotor activity and the degradation of pyramidal cells were significantly suppressed by intracerebroventricular injection of aprotinin, a plasmin inhibitor, at 4 h but not during FVO. These results suggest the importance of the t-PA/plasmin cascade during the early pathological stages of delayed neuronal death in the hippocampus following transient forebrain ischemia.

  20. 多巴胺对豚鼠听觉传入神经的抑制作用及其频率选择性%Suppressive effect and its frequency selection of dopamine on the cochlear auditory afferent nerve activity in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    侯志强; 余力生; 李兴启; 刘军

    2008-01-01

    Objective To investigate the suppressive effect and its frequency selection of dopamine on the cochlear auditory afferent nerve activity. To offer an important step in understanding the modulation of dopamine in the inner cell synaptic complex. Methods Forty guinea pigs were randomly divided into four groups and the whole intracochlear perfusions were performed: (1) perfused with artificial perilymph solutions; (2) perfused with artifical perilymph solutions containing 10 mmol/L dopamine; (3) perfused with artificial perilymph solutions containing 30 mmol/L dopamine; (4) perfused with artifical perilymph solutions containing 50 mmol/L dopamine. Compound action potential (CAP)evoked by different frequencies (250 Hz,500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz, 16 000 Hz) and cochlear microphonics (CM) evoked by4000 Hz tone burst were recorded from the roud window of guinea pigs before perfusion and 1 hours, 2 hours after perfusions. Results There was no significant difference in CAP threshold before and after perfusion in the artificial perilymph solutions group (P > 0.05) . An increase of CAP threshold of most detecting frequencies were observed in the three dopamine-perfused groups(P 0.05);灌流多巴胺后大部分频率的CAP阈值提高,与灌流前相比差异具有统计学意义(P值均0.05).结论 多巴胺对豚鼠听觉传入神经具有抑制性作用,而对外毛细胞无影响;这种抑制作用具有频率选择性,对高频纤维的抑制作用较强,而对低频的抑制作用较弱.

  1. Representation of speech in human auditory cortex: is it special?

    Science.gov (United States)

    Steinschneider, Mitchell; Nourski, Kirill V; Fishman, Yonatan I

    2013-11-01

    Successful categorization of phonemes in speech requires that the brain analyze the acoustic signal along both spectral and temporal dimensions. Neural encoding of the stimulus amplitude envelope is critical for parsing the speech stream into syllabic units. Encoding of voice onset time (VOT) and place of articulation (POA), cues necessary for determining phonemic identity, occurs within shorter time frames. An unresolved question is whether the neural representation of speech is based on processing mechanisms that are unique to humans and shaped by learning and experience, or is based on rules governing general auditory processing that are also present in non-human animals. This question was examined by comparing the neural activity elicited by speech and other complex vocalizations in primary auditory cortex of macaques, who are limited vocal learners, with that in Heschl's gyrus, the putative location of primary auditory cortex in humans. Entrainment to the amplitude envelope is neither specific to humans nor to human speech. VOT is represented by responses time-locked to consonant release and voicing onset in both humans and monkeys. Temporal representation of VOT is observed both for isolated syllables and for syllables embedded in the more naturalistic context of running speech. The fundamental frequency of male speakers is represented by more rapid neural activity phase-locked to the glottal pulsation rate in both humans and monkeys. In both species, the differential representation of stop consonants varying in their POA can be predicted by the relationship between the frequency selectivity of neurons and the onset spectra of the speech sounds. These findings indicate that the neurophysiology of primary auditory cortex is similar in monkeys and humans despite their vastly different experience with human speech, and that Heschl's gyrus is engaged in general auditory, and not language-specific, processing. This article is part of a Special Issue entitled

  2. Regional cerebral blood flow and glucose metabolism following transient forebrain ischemia.

    Science.gov (United States)

    Pulsinelli, W A; Levy, D E; Duffy, T E

    1982-05-01

    Progressive brain damage after transient cerebral ischemia may be related to changes in postischemic cerebral blood flow and metabolism. Regional cerebral blood flow (rCBF) and cerebral glucose utilization (rCGU) were measured in adult rats prior to, during (only rCBF), and serially after transient forebrain ischemia. Animals were subjected to 30 minutes of forebrain ischemia by occluding both common carotid arteries 24 hours after cauterizing the vertebral arteries. Regional CBF was measured by the indicator-fractionation technique using 4-iodo-[14C]-antipyrine. Regional CGU was measured by the 2-[14C]deoxyglucose method. The results were correlated with the distribution and progression of ischemic neuronal damage in animals subjected to an identical ischemic insult. Cerebral blood flow to forebrain after 30 minutes of moderate to severe ischemia (less than 10% control CBF) was characterized by 5 to 15 minutes of hyperemia; rCBF then fell below normal and remained low for as long as 24 hours. Post-ischemic glucose utilization in the forebrain, except in the hippocampus, was depressed below control values at 1 hour and either remained low (neocortex, striatum) or gradually rose to normal (white matter) by 48 hours. In the hippocampus, glucose utilization equaled the control value at 1 hour and fell below control between 24 and 48 hours. The appearance of moderate to severe morphological damage in striatum and hippocampus coincided with a late rise of rCBF above normal and with a fall of rCGU; the late depression of rCGU was usually preceded by a period during which metabolism was increased relative to adjacent tissue. Further refinement of these studies may help identify salvageable brain after ischemia and define ways to manipulate CBF and metabolism in the treatment of stroke.

  3. Brain-derived neurotrophic factor signaling is altered in the forebrain of Engrailed-2 knockout mice.

    Science.gov (United States)

    Zunino, G; Messina, A; Sgadò, P; Baj, G; Casarosa, S; Bozzi, Y

    2016-06-02

    Engrailed-2 (En2), a homeodomain transcription factor involved in regionalization and patterning of the midbrain and hindbrain regions has been associated to autism spectrum disorders (ASDs). En2 knockout (En2(-/-)) mice show ASD-like features accompanied by a significant loss of GABAergic subpopulations in the hippocampus and neocortex. Brain-derived neurotrophic factor (BDNF) is a crucial factor for the postnatal development of forebrain GABAergic neurons, and altered GABA signaling has been hypothesized to underlie the symptoms of ASD. Here we sought to determine whether interneuron loss in the En2(-/-) forebrain might be related to altered expression of BDNF and its signaling receptors. We first evaluated the expression of different BDNF mRNA isoforms in the neocortex and hippocampus of wild-type (WT) and En2(-/-) mice. Quantitative RT-PCR showed a marked down-regulation of several splicing variants of BDNF mRNA in the neocortex but not hippocampus of adult En2(-/-) mice, as compared to WT controls. Accordingly, levels of mature BDNF protein were lower in the neocortex but not hippocampus of En2(-/-) mice, as compared to WT. Increased levels of phosphorylated TrkB and decreased levels of p75 receptor were also detected in the neocortex of mutant mice. Accordingly, the expression of low density lipoprotein receptor (LDLR) and RhoA, two genes regulated via p75 was significantly altered in forebrain areas of mutant mice. These data indicate that BDNF signaling alterations might be involved in the anatomical changes observed in the En2(-/-) forebrain and suggest a pathogenic role of altered BDNF signaling in this mouse model of ASD.

  4. Activation of the Basal Forebrain by the Orexin/Hypocretin Neurons: Orexin International Symposium

    OpenAIRE

    Arrigoni, Elda; Mochizuki, Takatoshi; Scammell, Thomas E.

    2009-01-01

    The orexin neurons play an essential role in driving arousal and in maintaining normal wakefulness. Lack of orexin neurotransmission produces a chronic state of hypoarousal characterized by excessive sleepiness, frequent transitions between wake and sleep, and episodes of cataplexy. A growing body of research now suggests that the basal forebrain (BF) may be a key site through which the orexin-producing neurons promote arousal. Here we review anatomical, pharmacological and electrophysiologic...

  5. Theory of Auditory Thresholds in Primates

    Science.gov (United States)

    Harrison, Michael J.

    2001-03-01

    The influence of thermal pressure fluctuations at the tympanic membrane has been previously investigated as a possible determinant of the threshold of hearing in humans (L.J. Sivian and S.D. White, J. Acoust. Soc. Am. IV, 4;288(1933).). More recent work has focussed more precisely on the relation between statistical mechanics and sensory signal processing by biological means in creatures' brains (W. Bialek, in ``Physics of Biological Systems: from molecules to species'', H. Flyvberg et al, (Eds), p. 252; Springer 1997.). Clinical data on the frequency dependence of hearing thresholds in humans and other primates (W.C. Stebbins, ``The Acoustic Sense of Animals'', Harvard 1983.) has long been available. I have derived an expression for the frequency dependence of hearing thresholds in primates, including humans, by first calculating the frequency dependence of thermal pressure fluctuations at eardrums from damped normal modes excited in model ear canals of given simple geometry. I then show that most of the features of the clinical data are directly related to the frequency dependence of the ratio of thermal noise pressure arising from without to that arising from within the masking bandwidth which signals must dominate in order to be sensed. The higher intensity of threshold signals in primates smaller than humans, which is clinically observed over much but not all of the human auditory spectrum is shown to arise from their smaller meatus dimensions. note

  6. Infant Auditory Processing and Event-related Brain Oscillations

    Science.gov (United States)

    Musacchia, Gabriella; Ortiz-Mantilla, Silvia; Realpe-Bonilla, Teresa; Roesler, Cynthia P.; Benasich, April A.

    2015-01-01

    Rapid auditory processing and acoustic change detection abilities play a critical role in allowing human infants to efficiently process the fine spectral and temporal changes that are characteristic of human language. These abilities lay the foundation for effective language acquisition; allowing infants to hone in on the sounds of their native language. Invasive procedures in animals and scalp-recorded potentials from human adults suggest that simultaneous, rhythmic activity (oscillations) between and within brain regions are fundamental to sensory development; determining the resolution with which incoming stimuli are parsed. At this time, little is known about oscillatory dynamics in human infant development. However, animal neurophysiology and adult EEG data provide the basis for a strong hypothesis that rapid auditory processing in infants is mediated by oscillatory synchrony in discrete frequency bands. In order to investigate this, 128-channel, high-density EEG responses of 4-month old infants to frequency change in tone pairs, presented in two rate conditions (Rapid: 70 msec ISI and Control: 300 msec ISI) were examined. To determine the frequency band and magnitude of activity, auditory evoked response averages were first co-registered with age-appropriate brain templates. Next, the principal components of the response were identified and localized using a two-dipole model of brain activity. Single-trial analysis of oscillatory power showed a robust index of frequency change processing in bursts of Theta band (3 - 8 Hz) activity in both right and left auditory cortices, with left activation more prominent in the Rapid condition. These methods have produced data that are not only some of the first reported evoked oscillations analyses in infants, but are also, importantly, the product of a well-established method of recording and analyzing clean, meticulously collected, infant EEG and ERPs. In this article, we describe our method for infant EEG net

  7. Forebrain neuroanatomy of the neonatal and juvenile dolphin (T. truncatus and S. coeruloalba).

    Science.gov (United States)

    Parolisi, Roberta; Peruffo, Antonella; Messina, Silvia; Panin, Mattia; Montelli, Stefano; Giurisato, Maristella; Cozzi, Bruno; Bonfanti, Luca

    2015-01-01

    Knowledge of dolphin functional neuroanatomy mostly derives from post-mortem studies and non-invasive approaches (i.e., magnetic resonance imaging), due to limitations in experimentation on cetaceans. As a consequence the availability of well-preserved tissues for histology is scarce, and detailed histological analyses are referred mainly to adults. Here we studied the neonatal/juvenile brain in two species of dolphins, the bottlenose dolphin (Tursiops truncatus) and the striped dolphin (Stenella coeruleoalba), with special reference to forebrain regions. We analyzed cell density in subcortical nuclei, white/gray matter ratio, and myelination in selected regions at different anterior-posterior levels of the whole dolphin brain at different ages, to better define forebrain neuroanatomy and the developmental stage of the dolphin brain around birth. The analyses were extended to the periventricular germinal layer and the cerebellum, whose delayed genesis of the granule cell layer is a hallmark of postnatal development in the mammalian nervous system. Our results establish an atlas of the young dolphin forebrain and, on the basis of occurrence/absence of delayed neurogenic layers, confirm the stage of advanced brain maturation in these animals with respect to most terrestrial mammals.

  8. Forebrain neuroanatomy of the neonatal and juvenile dolphin (T. truncatus & S. coeruloalba

    Directory of Open Access Journals (Sweden)

    Roberta eParolisi

    2015-11-01

    Full Text Available Knowledge of dolphin functional neuroanatomy mostly derives from post-mortem studies and non-invasive approaches (i.e. magnetic resonance imaging, due to limitations in experimentation on cetaceans. As a consequence the availability of well-preserved tissues for histology is scarce, and detailed histological analyses are referred mainly to adults. Here we studied the neonatal/juvenile brain in two species of dolphins, the bottlenose dolphin (Tursiops truncatus and the striped dolphin (Stenella coeruleoalba, with special reference to forebrain regions. We analyzed cell density in subcortical nuclei, white/grey matter ratio, and myelination in selected regions at different anterior-posterior levels of the whole dolphin brain at different ages, to better define forebrain neuroanatomy and the developmental stage of the dolphin brain around birth. The analysis were extended to the periventricular germinal layer and the cerebellum, whose delayed genesis of the granule cell layer is a hallmark of postnatal development in the mammalian nervous system. Our results establish an atlas of the young dolphin forebrain and, on the basis of occurrence/absence of delayed neurogenic layers, confirm the stage of advanced brain maturation in these animals with respect to most terrestrial mammals.

  9. Activity of basal forebrain neurons in the rat during motivated behaviors.

    Science.gov (United States)

    Mink, J W; Sinnamon, H M; Adams, D B

    1983-04-01

    The activity of single neurons in the basal forebrain was recorded in the freely-moving rat with moveable fine-wire electrodes. Neural activity was observed while the water-deprived male rat was exposed to three different types of motivating stimuli that elicit locomotion in a running wheel: an estrous female rat; a drinking tube containing water; and grasping and lifting by the experimenter. The neural activity was also observed when the subject was presented with standardized sensory tests and during single pulse stimulation of other brain structures. A majority of the 76 neurons recorded in the forebrain changed their firing rate during orienting and/or locomotion in general (23 neurons) or during behavior related to only one of the specific motivational contexts: the conspecific female (4 neurons); water (7 neurons); or grasp by the experimenter (8 neurons). Whereas the neurons related to orienting and/or locomotion in general were scattered through various brain structures, those neurons related to specific motivational contexts were concentrated in specific areas: the sexually dimorphic nucleus of the medial preoptic area (conspecific female); lateral septum (water); and lateral preoptic area (water and grasp). The present results, although based on relatively few neurons, are consonant with results of research using other techniques. This indicates that analyses at the level of the single neuron promise to be useful for understanding the role of the basal forebrain in motivational systems.

  10. Widespread expression of BDNF but not NT3 by target areas of basal forebrain cholinergic neurons

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, H.S.; Hains, J.M.; Laramee, G.R.; Rosenthal, A.; Winslow, J.W. (Genentech, San Francisco, CA (USA))

    1990-10-12

    Brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) are homologs of the well-known neurotrophic factor nerve growth factor. The three members of this family display distinct patterns of target specificity. To examine the distribution in brain of messenger RNA for these molecules, in situ hybridization was performed. Cells hybridizing intensely to antisense BDNF probe were located throughout the major targets of the rat basal forebrain cholinergic system, that is, the hippocampus, amygdala, and neocortex. Strongly hybridizing cells were also observed in structures associated with the olfactory system. The distribution of NT3 mRNA in forebrain was much more limited. Within the hippocampus, labeled cells were restricted to CA2, the most medial portion of CA1, and the dentate gyrus. In human hippocampus, cells expressing BDNF and mRNA are distributed in a fashion similar to that observed in the rat. These findings point to both basal forebrain cholinergic cells and olfactory pathways as potential central targets for BDNF.

  11. CBP regulates the differentiation of interneurons from ventral forebrain neural precursors during murine development.

    Science.gov (United States)

    Tsui, David; Voronova, Anastassia; Gallagher, Denis; Kaplan, David R; Miller, Freda D; Wang, Jing

    2014-01-15

    The mechanisms that regulate appropriate genesis and differentiation of interneurons in the developing mammalian brain are of significant interest not only because interneurons play key roles in the establishment of neural circuitry, but also because when they are deficient, this can cause epilepsy. In this regard, one genetic syndrome that is associated with deficits in neural development and epilepsy is Rubinstein-Taybi Syndrome (RTS), where the transcriptional activator and histone acetyltransferase CBP is mutated and haploinsufficient. Here, we have asked whether CBP is necessary for the appropriate genesis and differentiation of interneurons in the murine forebrain, since this could provide an explanation for the epilepsy that is associated with RTS. We show that CBP is expressed in neural precursors within the embryonic medial ganglionic eminence (MGE), an area that generates the vast majority of interneurons for the cortex. Using primary cultures of MGE precursors, we show that knockdown of CBP causes deficits in differentiation of these precursors into interneurons and oligodendrocytes, and that overexpression of CBP is by itself sufficient to enhance interneuron genesis. Moreover, we show that levels of the neurotransmitter synthesis enzyme GAD67, which is expressed in inhibitory interneurons, are decreased in the dorsal and ventral forebrain of neonatal CBP(+/-) mice, indicating that CBP plays a role in regulating interneuron development in vivo. Thus, CBP normally acts to ensure the differentiation of appropriate numbers of forebrain interneurons, and when its levels are decreased, this causes deficits in interneuron development, providing a potential explanation for the epilepsy seen in individuals with RTS.

  12. Localization of tyrosine hydroxylase immunoreactive neurons in the forebrain of the guppy Poecilia reticulata.

    Science.gov (United States)

    Parafati, M; Senatori, O; Nicotra, A

    2009-10-01

    The current study reports for the first time the distribution of tyrosine hydroxylase immunoreactive (TH-ir) neurons in the forebrain of the guppy Poecilia reticulata. Numerous small TH-ir neurons were observed in the olfactory bulbs, located mainly in the periphery of the bulbs. The TH-ir telencephalic neurons are localized in the ventral telencephalic area where they are grouped in three distinct nuclei (Vv,Vd and Vp) composed of a small number of cells forming a continuous strip. The largest number of forebrain TH-ir neurons was observed in the diencephalon where both small and larger neurons are present. Diencephalic TH-ir neurons are subdivided in large nuclei located in the preoptic region (nSC, nPOp and nPOm), the thalamus (nDM), the pretectal region (nPPv and nAP), the hypothalamus (nPP and nRP) and the posterior tuberculum (nPT). Many diencephalic nuclei are distributed in periventricular regions and no TH-ir cells were observed in the paraventricular organ. A comparative analysis indicates that the present observations are consistent with the general pattern of TH-ir neurons distribution reported for the forebrain of other teleosts, but with some interspecies variability present, mainly in the diencephalon. This paper also provides valuable neuroanatomical information for P. reticulata, a teleost frequently used in toxicological tests, for future studies investigating the effects of environmental pollutants on the catecholaminergic system.

  13. Carrier-dependent temporal processing in an auditory interneuron.

    Science.gov (United States)

    Sabourin, Patrick; Gottlieb, Heather; Pollack, Gerald S

    2008-05-01

    Signal processing in the auditory interneuron Omega Neuron 1 (ON1) of the cricket Teleogryllus oceanicus was compared at high- and low-carrier frequencies in three different experimental paradigms. First, integration time, which corresponds to the time it takes for a neuron to reach threshold when stimulated at the minimum effective intensity, was found to be significantly shorter at high-carrier frequency than at low-carrier frequency. Second, phase locking to sinusoidally amplitude modulated signals was more efficient at high frequency, especially at high modulation rates and low modulation depths. Finally, we examined the efficiency with which ON1 detects gaps in a constant tone. As reflected by the decrease in firing rate in the vicinity of the gap, ON1 is better at detecting gaps at low-carrier frequency. Following a gap, firing rate increases beyond the pre-gap level. This "rebound" phenomenon is similar for low- and high-carrier frequencies.

  14. Dynamic crossmodal links revealed by steady-state responses in auditory-visual divided attention

    NARCIS (Netherlands)

    de Jong, Ritske; Toffanin, Paolo; Harbers, Marten; Martens, Sander

    2010-01-01

    Frequency tagging has been often used to study intramodal attention but not intermodal attention. We used EEG and simultaneous frequency tagging of auditory and visual sources to study intermodal focused and divided attention in detection and discrimination performance. Divided-attention costs were

  15. Auditory Pattern Recognition and Brief Tone Discrimination of Children with Reading Disorders

    Science.gov (United States)

    Walker, Marianna M.; Givens, Gregg D.; Cranford, Jerry L.; Holbert, Don; Walker, Letitia

    2006-01-01

    Auditory pattern recognition skills in children with reading disorders were investigated using perceptual tests involving discrimination of frequency and duration tonal patterns. A behavioral test battery involving recognition of the pattern of presentation of tone triads was used in which individual components differed in either frequency or…

  16. Auditory feedback affects perception of effort when exercising with a Pulley machine

    DEFF Research Database (Denmark)

    Bordegoni, Monica; Ferrise, Francesco; Grani, Francesco

    2013-01-01

    In this paper we describe an experiment that investigates the role of auditory feedback in affecting the perception of effort when using a physical pulley machine. Specifically, we investigated whether variations in the amplitude and frequency content of the pulley sound affect perception of effort....... Results show that variations in frequency content affect the perception of effort....

  17. Low power adder based auditory filter architecture.

    Science.gov (United States)

    Rahiman, P F Khaleelur; Jayanthi, V S

    2014-01-01

    Cochlea devices are powered up with the help of batteries and they should possess long working life to avoid replacing of devices at regular interval of years. Hence the devices with low power consumptions are required. In cochlea devices there are numerous filters, each responsible for frequency variant signals, which helps in identifying speech signals of different audible range. In this paper, multiplierless lookup table (LUT) based auditory filter is implemented. Power aware adder architectures are utilized to add the output samples of the LUT, available at every clock cycle. The design is developed and modeled using Verilog HDL, simulated using Mentor Graphics Model-Sim Simulator, and synthesized using Synopsys Design Compiler tool. The design was mapped to TSMC 65 nm technological node. The standard ASIC design methodology has been adapted to carry out the power analysis. The proposed FIR filter architecture has reduced the leakage power by 15% and increased its performance by 2.76%.

  18. 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.

  19. Practical Gammatone-Like Filters for Auditory Processing

    Directory of Open Access Journals (Sweden)

    Lyon RF

    2007-01-01

    Full Text Available This paper deals with continuous-time filter transfer functions that resemble tuning curves at particular set of places on the basilar membrane of the biological cochlea and that are suitable for practical VLSI implementations. The resulting filters can be used in a filterbank architecture to realize cochlea implants or auditory processors of increased biorealism. To put the reader into context, the paper starts with a short review on the gammatone filter and then exposes two of its variants, namely, the differentiated all-pole gammatone filter (DAPGF and one-zero gammatone filter (OZGF, filter responses that provide a robust foundation for modeling cochlea transfer functions. The DAPGF and OZGF responses are attractive because they exhibit certain characteristics suitable for modeling a variety of auditory data: level-dependent gain, linear tail for frequencies well below the center frequency, asymmetry, and so forth. In addition, their form suggests their implementation by means of cascades of N identical two-pole systems which render them as excellent candidates for efficient analog or digital VLSI realizations. We provide results that shed light on their characteristics and attributes and which can also serve as "design curves" for fitting these responses to frequency-domain physiological data. The DAPGF and OZGF responses are essentially a "missing link" between physiological, electrical, and mechanical models for auditory filtering.

  20. Practical Gammatone-Like Filters for Auditory Processing

    Directory of Open Access Journals (Sweden)

    R. F. Lyon

    2007-12-01

    Full Text Available This paper deals with continuous-time filter transfer functions that resemble tuning curves at particular set of places on the basilar membrane of the biological cochlea and that are suitable for practical VLSI implementations. The resulting filters can be used in a filterbank architecture to realize cochlea implants or auditory processors of increased biorealism. To put the reader into context, the paper starts with a short review on the gammatone filter and then exposes two of its variants, namely, the differentiated all-pole gammatone filter (DAPGF and one-zero gammatone filter (OZGF, filter responses that provide a robust foundation for modeling cochlea transfer functions. The DAPGF and OZGF responses are attractive because they exhibit certain characteristics suitable for modeling a variety of auditory data: level-dependent gain, linear tail for frequencies well below the center frequency, asymmetry, and so forth. In addition, their form suggests their implementation by means of cascades of N identical two-pole systems which render them as excellent candidates for efficient analog or digital VLSI realizations. We provide results that shed light on their characteristics and attributes and which can also serve as “design curves” for fitting these responses to frequency-domain physiological data. The DAPGF and OZGF responses are essentially a “missing link” between physiological, electrical, and mechanical models for auditory filtering.

  1. Merging functional and structural properties of the monkey auditory cortex

    Directory of Open Access Journals (Sweden)

    Olivier eJoly

    2014-07-01

    Full Text Available Recent neuroimaging studies in primates aim to define the functional properties of auditory cortical areas, especially areas beyond A1, in order to further our understanding of the auditory cortical organization. Precise mapping of functional magnetic resonance imaging (fMRI results and interpretation of their localizations among all the small auditory subfields remains challenging. To facilitate this mapping, we combined here information from cortical folding, micro-anatomy, surface-based atlas and tonotopic mapping. We used for the first time, phase-encoded fMRI design for mapping the monkey tonotopic organization. From posterior to anterior, we found a high-low-high progression of frequency preference on the superior temporal plane. We show a faithful representation of the fMRI results on a locally flattened surface of the superior temporal plane. In a tentative scheme to delineate core versus belt regions which share similar tonotopic organizations we used the ratio of T1-weighted and T2-weighted MR images as a measure of cortical myelination. Our results, presented along a co-registered surface-based atlas, can be interpreted in terms of a current model of the monkey auditory cortex.

  2. Tuned with a tune: Talker normalization via general auditory processes

    Directory of Open Access Journals (Sweden)

    Erika J C Laing

    2012-06-01

    Full Text Available Voices have unique acoustic signatures, contributing to the acoustic variability listeners must contend with in perceiving speech, and it has long been proposed that listeners normalize speech perception to information extracted from a talker’s speech. Initial attempts to explain talker normalization relied on extraction of articulatory referents, but recent studies of context-dependent auditory perception suggest that general auditory referents such as the long-term average spectrum (LTAS of a talker’s speech similarly affect speech perception. The present study aimed to differentiate the contributions of articulatory/linguistic versus auditory referents for context-driven talker normalization effects and, more specifically, to identify the specific constraints under which such contexts impact speech perception. Synthesized sentences manipulated to sound like different talkers influenced categorization of a subsequent speech target only when differences in the sentences’ LTAS were in the frequency range of the acoustic cues relevant for the target phonemic contrast. This effect was true both for speech targets preceded by spoken sentence contexts and for targets preceded by nonspeech tone sequences that were LTAS-matched to the spoken sentence contexts. Specific LTAS characteristics, rather than perceived talker, predicted the results suggesting that general auditory mechanisms play an important role in effects considered to be instances of perceptual talker normalization.

  3. Changes in otoacoustic emissions during selective auditory and visual attention.

    Science.gov (United States)

    Walsh, Kyle P; Pasanen, Edward G; McFadden, Dennis

    2015-05-01

    Previous studies have demonstrated that the otoacoustic emissions (OAEs) measured during behavioral tasks can have different magnitudes when subjects are attending selectively or not attending. The implication is that the cognitive and perceptual demands of a task can affect the first neural stage of auditory processing-the sensory receptors themselves. However, the directions of the reported attentional effects have been inconsistent, the magnitudes of the observed differences typically have been small, and comparisons across studies have been made difficult by significant procedural differences. In this study, a nonlinear version of the stimulus-frequency OAE (SFOAE), called the nSFOAE, was used to measure cochlear responses from human subjects while they simultaneously performed behavioral tasks requiring selective auditory attention (dichotic or diotic listening), selective visual attention, or relative inattention. Within subjects, the differences in nSFOAE magnitude between inattention and attention conditions were about 2-3 dB for both auditory and visual modalities, and the effect sizes for the differences typically were large for both nSFOAE magnitude and phase. These results reveal that the cochlear efferent reflex is differentially active during selective attention and inattention, for both auditory and visual tasks, although they do not reveal how attention is improved when efferent activity is greater.

  4. Implications of blast exposure for central auditory function: A review

    Directory of Open Access Journals (Sweden)

    Frederick J. Gallun, PhD

    2012-10-01

    Full Text Available Auditory system functions, from peripheral sensitivity to central processing capacities, are all at risk from a blast event. Accurate encoding of auditory patterns in time, frequency, and space are required for a clear understanding of speech and accurate localization of sound sources in environments with background noise, multiple sound sources, and/or reverberation. Further work is needed to refine the battery of clinical tests sensitive to the sorts of central auditory dysfunction observed in individuals with blast exposure. Treatment options include low-gain hearing aids, remote-microphone technology, and auditory-training regimens, but clinical evidence does not yet exist for recommending one or more of these options. As this population ages, the natural aging process and other potential brain injuries (such as stroke and blunt trauma may combine with blast-related brain changes to produce a population for which the current clinical diagnostic and treatment tools may prove inadequate. It is important to maintain an updated understanding of the scope of the issues present in this population and to continue to identify those solutions that can provide measurable improvements in the lives of Veterans who have been exposed to high-intensity blasts during the course of their military service.

  5. Segmental processing in the human auditory dorsal stream.

    Science.gov (United States)

    Zaehle, Tino; Geiser, Eveline; Alter, Kai; Jancke, Lutz; Meyer, Martin

    2008-07-18

    In the present study we investigated the functional organization of sublexical auditory perception with specific respect to auditory spectro-temporal processing in speech and non-speech sounds. Participants discriminated verbal and nonverbal auditory stimuli according to either spectral or temporal acoustic features in the context of a sparse event-related functional magnetic resonance imaging (fMRI) study. Based on recent models of speech processing, we hypothesized that auditory segmental processing, as is required in the discrimination of speech and non-speech sound according to its temporal features, will lead to a specific involvement of a left-hemispheric dorsal processing network comprising the posterior portion of the inferior frontal cortex and the inferior parietal lobe. In agreement with our hypothesis results revealed significant responses in the posterior part of the inferior frontal gyrus and the parietal operculum of the left hemisphere when participants had to discriminate speech and non-speech stimuli based on subtle temporal acoustic features. In contrast, when participants had to discriminate speech and non-speech stimuli on the basis of changes in the frequency content, we observed bilateral activations along the middle temporal gyrus and superior temporal sulcus. The results of the present study demonstrate an involvement of the dorsal pathway in the segmental sublexical analysis of speech sounds as well as in the segmental acoustic analysis of non-speech sounds with analogous spectro-temporal characteristics.

  6. Auditory intensity processing: Effect of MRI background noise.

    Science.gov (United States)

    Angenstein, Nicole; Stadler, Jörg; Brechmann, André

    2016-03-01

    Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise.

  7. Dynamic range adaptation to sound level statistics in the auditory nerve.

    Science.gov (United States)

    Wen, Bo; Wang, Grace I; Dean, Isabel; Delgutte, Bertrand

    2009-11-04

    The auditory system operates over a vast range of sound pressure levels (100-120 dB) with nearly constant discrimination ability across most of the range, well exceeding the dynamic range of most auditory neurons (20-40 dB). Dean et al. (2005) have reported that the dynamic range of midbrain auditory neurons adapts to the distribution of sound levels in a continuous, dynamic stimulus by shifting toward the most frequently occurring level. Here, we show that dynamic range adaptation, distinct from classic firing rate adaptation, also occurs in primary auditory neurons in anesthetized cats for tone and noise stimuli. Specifically, the range of sound levels over which firing rates of auditory nerve (AN) fibers grows rapidly with level shifts nearly linearly with the most probable levels in a dynamic sound stimulus. This dynamic range adaptation was observed for fibers with all characteristic frequencies and spontaneous discharge rates. As in the midbrain, dynamic range adaptation improved the precision of level coding by the AN fiber population for the prevailing sound levels in the stimulus. However, dynamic range adaptation in the AN was weaker than in the midbrain and not sufficient (0.25 dB/dB, on average, for broadband noise) to prevent a significant degradation of the precision of level coding by the AN population above 60 dB SPL. These findings suggest that adaptive processing of sound levels first occurs in the auditory periphery and is enhanced along the auditory pathway.

  8. Auditory and audio-visual processing in patients with cochlear, auditory brainstem, and auditory midbrain implants: An EEG study.

    Science.gov (United States)

    Schierholz, Irina; Finke, Mareike; Kral, Andrej; Büchner, Andreas; Rach, Stefan; Lenarz, Thomas; Dengler, Reinhard; Sandmann, Pascale

    2017-04-01

    There is substantial variability in speech recognition ability across patients with cochlear implants (CIs), auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs). To better understand how this variability is related to central processing differences, the current electroencephalography (EEG) study compared hearing abilities and auditory-cortex activation in patients with electrical stimulation at different sites of the auditory pathway. Three different groups of patients with auditory implants (Hannover Medical School; ABI: n = 6, CI: n = 6; AMI: n = 2) performed a speeded response task and a speech recognition test with auditory, visual, and audio-visual stimuli. Behavioral performance and cortical processing of auditory and audio-visual stimuli were compared between groups. ABI and AMI patients showed prolonged response times on auditory and audio-visual stimuli compared with NH listeners and CI patients. This was confirmed by prolonged N1 latencies and reduced N1 amplitudes in ABI and AMI patients. However, patients with central auditory implants showed a remarkable gain in performance when visual and auditory input was combined, in both speech and non-speech conditions, which was reflected by a strong visual modulation of auditory-cortex activation in these individuals. In sum, the results suggest that the behavioral improvement for audio-visual conditions in central auditory implant patients is based on enhanced audio-visual interactions in the auditory cortex. Their findings may provide important implications for the optimization of electrical stimulation and rehabilitation strategies in patients with central auditory prostheses. Hum Brain Mapp 38:2206-2225, 2017. © 2017 Wiley Periodicals, Inc.

  9. Auditory Hallucinations Nomenclature and Classification

    NARCIS (Netherlands)

    Blom, Jan Dirk; Sommer, Iris E. C.

    2010-01-01

    Introduction: The literature on the possible neurobiologic correlates of auditory hallucinations is expanding rapidly. For an adequate understanding and linking of this emerging knowledge, a clear and uniform nomenclature is a prerequisite. The primary purpose of the present article is to provide an

  10. Nigel: A Severe Auditory Dyslexic

    Science.gov (United States)

    Cotterell, Gill

    1976-01-01

    Reported is the case study of a boy with severe auditory dyslexia who received remedial treatment from the age of four and progressed through courses at a technical college and a 3-year apprenticeship course in mechanics by the age of eighteen. (IM)

  11. Role of auditory feedback in speech produced by cochlear implanted adults and children

    Science.gov (United States)

    Bharadwaj, Sneha V.; Tobey, Emily A.; Assmann, Peter F.; Katz, William F.

    2002-05-01

    A prominent theory of speech production proposes that speech segments are largely controlled by reference to an internal model, with minimal reliance on auditory feedback. This theory also maintains that suprasegmental aspects of speech are directly regulated by auditory feedback. Accordingly, if a talker is briefly deprived of auditory feedback speech segments should not be affected, but suprasegmental properties should show significant change. To test this prediction, comparisons were made between speech samples obtained from cochlear implant users who repeated words under two conditions (1) implant device turned ON, and (2) implant switched OFF immediately before the repetition of each word. To determine whether producing unfamiliar speech requires greater reliance on auditory feedback than producing familiar speech, English and French words were elicited from English-speaking subjects. Subjects were congenitally deaf children (n=4) and adventitiously deafened adults (n=4). Vowel fundamental frequency and formant frequencies, vowel and syllable durations, and fricative spectral moments were analyzed. Preliminary data only partially confirm the predictions, in that both segmental and suprasegmental aspects of speech were significantly modified in the absence of auditory feedback. Modifications were greater for French compared to English words, suggesting greater reliance on auditory feedback for unfamiliar words. [Work supported by NIDCD.

  12. Perception of stochastically undersampled sound waveforms: A model of auditory deafferentation

    Directory of Open Access Journals (Sweden)

    Enrique A Lopez-Poveda

    2013-07-01

    Full Text Available Auditory deafferentation, or permanent loss of auditory nerve afferent terminals, occurs after noise overexposure and aging and may accompany many forms of hearing loss. It could cause significant auditory impairment but is undetected by regular clinical tests and so its effects on perception are poorly understood. Here, we hypothesize and test a neural mechanism by which deafferentation could deteriorate perception. The basic idea is that the spike train produced by each auditory afferent resembles a stochastically digitized version of the sound waveform and that the quality of the waveform representation in the whole nerve depends on the number of aggregated spike trains or auditory afferents. We reason that because spikes occur stochastically in time with a higher probability for high- than for low-intensity sounds, more afferents would be required for the nerve to faithfully encode high-frequency or low-intensity waveform features than low-frequency or high-intensity features. Deafferentation would thus degrade the encoding of these features. We further reason that due to the stochastic nature of nerve firing, the degradation would be greater in noise than in quiet. This hypothesis is tested using a vocoder. Sounds were filtered through ten adjacent frequency bands. For the signal in each band, multiple stochastically subsampled copies were obtained to roughly mimic different stochastic representations of that signal conveyed by different auditory afferents innervating a given cochlear region. These copies were then aggregated to obtain an acoustic stimulus. Tone detection and speech identification tests were performed by young, normal-hearing listeners using different numbers of stochastic samplers per frequency band in the vocoder. Results support the hypothesis that stochastic undersampling of the sound waveform, inspired by deafferentation, impairs speech perception in noise more than in quiet, consistent with auditory aging effects.

  13. Neural plasticity expressed in central auditory structures with and without tinnitus

    Directory of Open Access Journals (Sweden)

    Larry E Roberts

    2012-05-01

    Full Text Available Sensory training therapies for tinnitus are based on the assumption that, notwithstanding neural changes related to tinnitus, auditory training can alter the response properties of neurons in auditory pathways. To address this question, we investigated whether brain changes induced by sensory training in tinnitus sufferers and measured by EEG are similar to those induced in age and hearing loss matched individuals without tinnitus trained on the same auditory task. Auditory training was given using a 5 kHz 40-Hz amplitude-modulated sound that was in the tinnitus frequency region of the tinnitus subjects and enabled extraction of the 40-Hz auditory steady-state response (ASSR and P2 transient response known to localize to primary and nonprimary auditory cortex, respectively. P2 amplitude increased with training equally in participants with tinnitus and in control subjects, suggesting normal remodeling of nonprimary auditory regions in tinnitus. However, training-induced changes in the ASSR differed between the tinnitus and control groups. In controls ASSR phase advanced toward the stimulus waveform by about ten degrees over training, in agreement with previous results obtained in young normal hearing individuals. However, ASSR phase did not change significantly with training in the tinnitus group, although some participants showed phase shifts resembling controls. On the other hand, ASSR amplitude increased with training in the tinnitus group, whereas in controls this response (which is difficult to remodel in young normal hearing subjects did not change with training. These results suggest that neural changes related to tinnitus altered how neural plasticity was expressed in the region of primary but not nonprimary auditory cortex. Auditory training did not reduce tinnitus loudness although a small effect on the tinnitus spectrum was detected.

  14. Reversible induction of phantom auditory sensations through simulated unilateral hearing loss.

    Directory of Open Access Journals (Sweden)

    Roland Schaette

    Full Text Available Tinnitus, a phantom auditory sensation, is associated with hearing loss in most cases, but it is unclear if hearing loss causes tinnitus. Phantom auditory sensations can be induced in normal hearing listeners when they experience severe auditory deprivation such as confinement in an anechoic chamber, which can be regarded as somewhat analogous to a profound bilateral hearing loss. As this condition is relatively uncommon among tinnitus patients, induction of phantom sounds by a lesser degree of auditory deprivation could advance our understanding of the mechanisms of tinnitus. In this study, we therefore investigated the reporting of phantom sounds after continuous use of an earplug. 18 healthy volunteers with normal hearing wore a silicone earplug continuously in one ear for 7 days. The attenuation provided by the earplugs simulated a mild high-frequency hearing loss, mean attenuation increased from 30 dB at 3 and 4 kHz. 14 out of 18 participants reported phantom sounds during earplug use. 11 participants presented with stable phantom sounds on day 7 and underwent tinnitus spectrum characterization with the earplug still in place. The spectra showed that the phantom sounds were perceived predominantly as high-pitched, corresponding to the frequency range most affected by the earplug. In all cases, the auditory phantom disappeared when the earplug was removed, indicating a causal relation between auditory deprivation and phantom sounds. This relation matches the predictions of our computational model of tinnitus development, which proposes a possible mechanism by which a stabilization of neuronal activity through homeostatic plasticity in the central auditory system could lead to the development of a neuronal correlate of tinnitus when auditory nerve activity is reduced due to the earplug.

  15. A comparison of auditory brainstem responses across diving bird species

    Science.gov (United States)

    Crowell, Sara E.; Berlin, Alicia; Carr, Catherine E; Olsen, Glenn H.; Therrien, Ronald E; Yannuzzi, Sally E; Ketten, Darlene R

    2015-01-01

    There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al., Proc Natl Acad Sci USA 63:676–680, 1969). We, therefore, measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of the greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e., frequency at the greatest intensity, of all species' vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range.

  16. Spectral and temporal processing in rat posterior auditory cortex.

    Science.gov (United States)

    Pandya, Pritesh K; Rathbun, Daniel L; Moucha, Raluca; Engineer, Navzer D; Kilgard, Michael P

    2008-02-01

    The rat auditory cortex is divided anatomically into several areas, but little is known about the functional differences in information processing between these areas. To determine the filter properties of rat posterior auditory field (PAF) neurons, we compared neurophysiological responses to simple tones, frequency modulated (FM) sweeps, and amplitude modulated noise and tones with responses of primary auditory cortex (A1) neurons. PAF neurons have excitatory receptive fields that are on average 65% broader than A1 neurons. The broader receptive fields of PAF neurons result in responses to narrow and broadband inputs that are stronger than A1. In contrast to A1, we found little evidence for an orderly topographic gradient in PAF based on frequency. These neurons exhibit latencies that are twice as long as A1. In response to modulated tones and noise, PAF neurons adapt to repeated stimuli at significantly slower rates. Unlike A1, neurons in PAF rarely exhibit facilitation to rapidly repeated sounds. Neurons in PAF do not exhibit strong selectivity for rate or direction of narrowband one octave FM sweeps. These results indicate that PAF, like nonprimary visual fields, processes sensory information on larger spectral and longer temporal scales than primary cortex.

  17. Adaptation in the auditory system: an overview

    Directory of Open Access Journals (Sweden)

    David ePérez-González

    2014-02-01

    Full Text Available The early stages of the auditory system need to preserve the timing information of sounds in order to extract the basic features of acoustic stimuli. At the same time, different processes of neuronal adaptation occur at several levels to further process the auditory information. For instance, auditory nerve fiber responses already experience adaptation of their firing rates, a type of response that can be found in many other auditory nuclei and may be useful for emphasizing the onset of the stimuli. However, it is at higher levels in the auditory hierarchy where more sophisticated types of neuronal processing take place. For example, stimulus-specific adaptation, where neurons show adaptation to frequent, repetitive stimuli, but maintain their responsiveness to stimuli with different physical characteristics, thus representing a distinct kind of processing that may play a role in change and deviance detection. In the auditory cortex, adaptation takes more elaborate forms, and contributes to the processing of complex sequences, auditory scene analysis and attention. Here we review the multiple types of adaptation that occur in the auditory system, which are part of the pool of resources that the neurons employ to process the auditory scene, and are critical to a proper understanding of the neuronal mechanisms that govern auditory perception.

  18. Auditory Dysfunction in Patients with Cerebrovascular Disease

    Directory of Open Access Journals (Sweden)

    Sadaharu Tabuchi

    2014-01-01

    Full Text Available Auditory dysfunction is a common clinical symptom that can induce profound effects on the quality of life of those affected. Cerebrovascular disease (CVD is the most prevalent neurological disorder today, but it has generally been considered a rare cause of auditory dysfunction. However, a substantial proportion of patients with stroke might have auditory dysfunction that has been underestimated due to difficulties with evaluation. The present study reviews relationships between auditory dysfunction and types of CVD including cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, cerebrovascular malformation, moyamoya disease, and superficial siderosis. Recent advances in the etiology, anatomy, and strategies to diagnose and treat these conditions are described. The numbers of patients with CVD accompanied by auditory dysfunction will increase as the population ages. Cerebrovascular diseases often include the auditory system, resulting in various types of auditory dysfunctions, such as unilateral or bilateral deafness, cortical deafness, pure word deafness, auditory agnosia, and auditory hallucinations, some of which are subtle and can only be detected by precise psychoacoustic and electrophysiological testing. The contribution of CVD to auditory dysfunction needs to be understood because CVD can be fatal if overlooked.

  19. The auditory brainstem is a barometer of rapid auditory learning.

    Science.gov (United States)

    Skoe, E; Krizman, J; Spitzer, E; Kraus, N

    2013-07-23

    To capture patterns in the environment, neurons in the auditory brainstem rapidly alter their firing based on the statistical properties of the soundscape. How this neural sensitivity relates to behavior is unclear. We tackled this question by combining neural and behavioral measures of statistical learning, a general-purpose learning mechanism governing many complex behaviors including language acquisition. We recorded complex auditory brainstem responses (cABRs) while human adults implicitly learned to segment patterns embedded in an uninterrupted sound sequence based on their statistical characteristics. The brainstem's sensitivity to statistical structure was measured as the change in the cABR between a patterned and a pseudo-randomized sequence composed from the same set of sounds but differing in their sound-to-sound probabilities. Using this methodology, we provide the first demonstration that behavioral-indices of rapid learning relate to individual differences in brainstem physiology. We found that neural sensitivity to statistical structure manifested along a continuum, from adaptation to enhancement, where cABR enhancement (patterned>pseudo-random) tracked with greater rapid statistical learning than adaptation. Short- and long-term auditory experiences (days to years) are known to promote brainstem plasticity and here we provide a conceptual advance by showing that the brainstem is also integral to rapid learning occurring over minutes.

  20. A Binaural Neuromorphic Auditory Sensor for FPGA: A Spike Signal Processing Approach.

    Science.gov (United States)

    Jimenez-Fernandez, Angel; Cerezuela-Escudero, Elena; Miro-Amarante, Lourdes; Dominguez-Moralse, Manuel Jesus; de Asis Gomez-Rodriguez, Francisco; Linares-Barranco, Alejandro; Jimenez-Moreno, Gabriel

    2017-04-01

    This paper presents a new architecture, design flow, and field-programmable gate array (FPGA) implementation analysis of a neuromorphic binaural auditory sensor, designed completely in the spike domain. Unlike digital cochleae that decompose audio signals using classical digital signal processing techniques, the model presented in this paper processes information directly encoded as spikes using pulse frequency modulation and provides a set of frequency-decomposed audio information using an address-event representation interface. In this case, a systematic approach to design led to a generic process for building, tuning, and implementing audio frequency decomposers with different features, facilitating synthesis with custom features. This allows researchers to implement their own parameterized neuromorphic auditory systems in a low-cost FPGA in order to study the audio processing and learning activity that takes place in the brain. In this paper, we present a 64-channel binaural neuromorphic auditory system implemented in a Virtex-5 FPGA using a commercial development board. The system was excited with a diverse set of audio signals in order to analyze its response and characterize its features. The neuromorphic auditory system response times and frequencies are reported. The experimental results of the proposed system implementation with 64-channel stereo are: a frequency range between 9.6 Hz and 14.6 kHz (adjustable), a maximum output event rate of 2.19 Mevents/s, a power consumption of 29.7 mW, the slices requirements of 11141, and a system clock frequency of 27 MHz.

  1. Directionality of auditory nerve fiber responses to pure tone stimuli in the grassfrog, Rana temporaria. I. Spike rate responses

    DEFF Research Database (Denmark)

    Jørgensen, M B; Christensen-Dalsgaard, J

    1997-01-01

    We studied the directionality of spike rate responses of auditory nerve fibers of the grassfrog, Rana temporaria, to pure tone stimuli. All auditory fibers showed spike rate directionality. The strongest directionality was seen at low frequencies (200-400 Hz), where the spike rate could change by...

  2. 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)

  3. Peripheral auditory processing and speech reception in impaired hearing

    DEFF Research Database (Denmark)

    Strelcyk, Olaf

    One of the most common complaints of people with impaired hearing concerns their difficulty with understanding speech. Particularly in the presence of background noise, hearing-impaired people often encounter great difficulties with speech communication. In most cases, the problem persists even i....... Overall, this work provides insights into factors affecting auditory processing in listeners with impaired hearing and may have implications for future models of impaired auditory signal processing as well as advanced compensation strategies....... if reduced audibility has been compensated for by hearing aids. It has been hypothesized that part of the difficulty arises from changes in the perception of sounds that are well above hearing threshold, such as reduced frequency selectivity and deficits in the processing of temporal fine structure (TFS...

  4. Classification of Underwater Target Echoes Based on Auditory Perception Characteristics

    Institute of Scientific and Technical Information of China (English)

    Xiukun Li; Xiangxia Meng; Hang Liu; Mingye Liu

    2014-01-01

    In underwater target detection, the bottom reverberation has some of the same properties as the target echo, which has a great impact on the performance. It is essential to study the difference between target echo and reverberation. In this paper, based on the unique advantage of human listening ability on objects distinction, the Gammatone filter is taken as the auditory model. In addition, time-frequency perception features and auditory spectral features are extracted for active sonar target echo and bottom reverberation separation. The features of the experimental data have good concentration characteristics in the same class and have a large amount of differences between different classes, which shows that this method can effectively distinguish between the target echo and reverberation.

  5. Forebrain development in fetal MRI: evaluation of anatomical landmarks before gestational week 27

    Energy Technology Data Exchange (ETDEWEB)

    Schmook, Maria T.; Weber, Michael; Kasprian, Gregor; Nemec, Stefan; Prayer, Daniela [Medical University of Vienna, Department of Radiology/Division of Neuro- and Musculoskeletal Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Integrative Morphology Group, Center for Anatomy and Cell Biology, Vienna (Austria); Krampl-Bettelheim, Elisabeth [Department of Obstetrics and Gynecology / Division of Obstetrics and Feto-maternal Medicine, Vienna (Austria)

    2010-06-15

    Forebrain malformations include some of the most severe developmental anomalies and require early diagnosis. The proof of normal or abnormal prosencephalic development may have an influence on further management in the event of a suspected fetal malformation. The purpose of this retrospective study was to evaluate the detectability of anatomical landmarks of forebrain development using in vivo fetal magnetic resonance imaging (MRI) before gestational week (gw) 27. MRI studies of 83 singleton fetuses (gw 16-26, average {+-}sd: gw 22 {+-} 2) performed at 1.5 Tesla were assessed. T2-weighted (w) fast spin echo, T1w gradient-echo and diffusion-weighted sequences were screened for the detectability of anatomical landmarks as listed below. The interhemispheric fissure, ocular bulbs, corpus callosum, infundibulum, chiasm, septum pellucidum (SP), profile, and palate were detectable in 95%, 95%, 89%, 87%, 82%, 81%, 78%, 78% of cases. Olfactory tracts were more easily delineated than bulbs and sulci (37% versus 18% and 8%), with significantly higher detection rates in the coronal plane. The pituitary gland could be detected on T1w images in 60% with an increasing diameter with gestational age (p=0.041). The delineation of olfactory tracts (coronal plane), chiasm, SP and pituitary gland were significantly increased after week 21 (p<0.05). Pathologies were found in 28% of cases. This study provides detection rates for anatomical landmarks of forebrain development with fetal MRI before gw 27. Several anatomical structures are readily detectable with routine fetal MRI sequences; thus, if these landmarks are not delineable, it should raise the suspicion of a pathology. Recommendations regarding favorable sequences/planes are provided. (orig.)

  6. A Detection-Theoretic Analysis of Auditory Streaming and Its Relation to Auditory Masking

    Directory of Open Access Journals (Sweden)

    An-Chieh Chang

    2016-09-01

    Full Text Available Research on hearing has long been challenged with understanding our exceptional ability to hear out individual sounds in a mixture (the so-called cocktail party problem. Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming. The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking. The two phenomena are clearly related, but that relation has never been evaluated analytically. This article offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The key to establishing this relation is the function linking performance to the information divergence of the tone sequences, DKL (a measure of the statistical separation of their parameters. A strong prediction is that streaming and masking of tones will be a common function of DKL provided that the statistical properties of sequences are symmetric. Results of experiments are reported supporting this prediction.

  7. A Detection-Theoretic Analysis of Auditory Streaming and Its Relation to Auditory Masking.

    Science.gov (United States)

    Chang, An-Chieh; Lutfi, Robert; Lee, Jungmee; Heo, Inseok

    2016-09-18

    Research on hearing has long been challenged with understanding our exceptional ability to hear out individual sounds in a mixture (the so-called cocktail party problem). Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming). The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking). The two phenomena are clearly related, but that relation has never been evaluated analytically. This article offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The key to establishing this relation is the function linking performance to the information divergence of the tone sequences, DKL (a measure of the statistical separation of their parameters). A strong prediction is that streaming and masking of tones will be a common function of DKL provided that the statistical properties of sequences are symmetric. Results of experiments are reported supporting this prediction.

  8. The forebrain of the blind cave fish Astyanax hubbsi (Characidae). I. General anatomy of the telencephalon.

    Science.gov (United States)

    Riedel, G

    1997-01-01

    This paper presents a survey of the cell groups in the telencephalon of the teleost Astyanax hubbsi, based on series of transverse sections stained with the Nissl-Klüver-Barrera and Bodian procedures. The work was conducted for two reasons. Firstly, it was intended to determine the contribution of the forebrain of blind cave fish to certain forms of behavior. An understanding of the anatomy of the telencephalic organization is essential for such a neuroethological approach. The second purpose was to provide the cytoarchitectural basis for the experimental analysis of the fiber connectivity of the telencephalon of A. hubbsi. Furthermore, information about the forebrain of characids is widely lacking, and this study may thus provide important knowledge about the cellular organization of characid forebrains for comparative anatomists. The brain of A. hubbsi is slender and elongated. Both optic nerves and optic tectum are reduced. Three longitudinal sulci-s. ypsiliformis, s. externus and s. limitans telencephali-can be distinguished in the telencephalon. A fiber lamina reaching from the s. externus to the s. limitans telencephali separates the area dorsalis (D) from the area ventralis telencephali (V). The two hemispheres are connected by fibers decussating in the anterior commissure. Although cross sections revealed no distinct fiber laminae between cytoarchitectonic components, 17 cell masses could be delineated: ten of these belong to D, seven to V. The topological analysis yielded the following results. The dorsal telencephalon D consists of three longitudinal columns, termed pars medialis (Dm), pars dorsalis and centralis (Dd and Dc) considered together, and par lateralis (Dl), which converge into a uniform posterior part (Dp). The columns can be divided into several subregions: Dm1 and Dm2, as well as Dlv and Dld, precommissurally, Dm3 and Dm4 postcommisurally. At polus posterior levels nucleus tenia can be identified. The ventral telencephalon (V) is arranged

  9. Tolerance of nestin+ cholinergic neurons in the basal forebrain against colchicine-induced cytotoxicity

    Institute of Scientific and Technical Information of China (English)

    Jing Yu; Kaihua Guo; Dongpei Li; Jinhai Duan; Juntao Zou; Junhua Yang; Zhibin Yao

    2011-01-01

    In the present study we injected colchicine into the lateral ventricle of Sprague-Dawley rats to investigate the effects of colchicine on the number of different-type neurons in the basal forebrain and to search for neurons resistant to injury. After colchicine injection, the number of nestin+ cholinergic neurons was decreased at 1 day, but increased at 3 days and peaked at 14-28 days. The quantity of nestin- cholinergic neurons, parvalbumin-positive neurons and choline acetyl transferase-positive neurons decreased gradually. Our results indicate that nestin+ cholinergic neurons possess better tolerance to colchicine-induced neurotoxicity.

  10. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  11. LRP2 is an auxiliary SHH receptor required to condition the forebrain ventral midline for inductive signals.

    Science.gov (United States)

    Christ, Annabel; Christa, Anna; Kur, Esther; Lioubinski, Oleg; Bachmann, Sebastian; Willnow, Thomas E; Hammes, Annette

    2012-02-14

    Sonic hedgehog (SHH) is a regulator of forebrain development that acts through its receptor, patched 1. However, little is known about cellular mechanisms at neurulation, whereby SHH from the prechordal plate governs specification of the rostral diencephalon ventral midline (RDVM), a major forebrain organizer. We identified LRP2, a member of the LDL receptor gene family, as a component of the SHH signaling machinery in the RDVM. LRP2 acts as an apical SHH-binding protein that sequesters SHH in its target field and controls internalization and cellular trafficking of SHH/patched 1 complexes. Lack of LRP2 in mice and in cephalic explants results in failure to respond to SHH, despite functional expression of patched 1 and smoothened, whereas overexpression of LRP2 variants in cells increases SHH signaling capacity. Our data identify a critical role for LRP2 in SHH signaling and reveal the molecular mechanism underlying forebrain anomalies in mice and patients with Lrp2 defects.

  12. Speech distortion measure based on auditory properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo; HU Xiulin; ZHANG Yunyu; ZHU Yaoting

    2000-01-01

    The Perceptual Spectrum Distortion (PSD), based on auditory properties of human being, is presented to measure speech distortion. The PSD measure calculates the speech distortion distance by simulating the auditory properties of human being and converting short-time speech power spectrum to auditory perceptual spectrum. Preliminary simulative experiments in comparison with the Itakura measure have been done. The results show that the PSD measure is a perferable speech distortion measure and more consistent with subjective assessment of speech quality.

  13. 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...

  14. Plasticity in the rat posterior auditory field following nucleus basalis stimulation.

    Science.gov (United States)

    Puckett, Amanda C; Pandya, Pritesh K; Moucha, Raluca; Dai, WeiWei; Kilgard, Michael P

    2007-07-01

    Classical conditioning paradigms have been shown to cause frequency-specific plasticity in both primary and secondary cortical areas. Previous research demonstrated that repeated pairing of nucleus basalis (NB) stimulation with a tone results in plasticity in primary auditory cortex (A1), mimicking the changes observed after classical conditioning. However, few studies have documented the effects of similar paradigms in secondary cortical areas. The purpose of this study was to quantify plasticity in the posterior auditory field (PAF) of the rat after NB stimulation paired with a high-frequency tone. NB-tone pairing increased the frequency selectivity of PAF sites activated by the paired tone. This frequency-specific receptive field size narrowing led to a reorganization of PAF such that responses to low- and mid-frequency tones were reduced by 40%. Plasticity in A1 was consistent with previous studies -- pairing a high-frequency tone with NB stimulation expanded the high-frequency region of the frequency map. Receptive field sizes did not change, but characteristic frequencies in A1 were shifted after NB-tone pairing. These results demonstrate that experience-dependent plasticity can take different forms in both A1 and secondary auditory cortex.

  15. Seeing the song: left auditory structures may track auditory-visual dynamic alignment.

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    Julia A Mossbridge

    Full Text Available Auditory and visual signals generated by a single source tend to be temporally correlated, such as the synchronous sounds of footsteps and the limb movements of a walker. Continuous tracking and comparison of the dynamics of auditory-visual streams is thus useful for the perceptual binding of information arising from a common source. Although language-related mechanisms have been implicated in the tracking of speech-related auditory-visual signals (e.g., speech sounds and lip movements, it is not well known what sensory mechanisms generally track ongoing auditory-visual synchrony for non-speech signals in a complex auditory-visual environment. To begin to address this question, we used music and visual displays that varied in the dynamics of multiple features (e.g., auditory loudness and pitch; visual luminance, color, size, motion, and organization across multiple time scales. Auditory activity (monitored using auditory steady-state responses, ASSR was selectively reduced in the left hemisphere when the music and dynamic visual displays were temporally misaligned. Importantly, ASSR was not affected when attentional engagement with the music was reduced, or when visual displays presented dynamics clearly dissimilar to the music. These results appear to suggest that left-lateralized auditory mechanisms are sensitive to auditory-visual temporal alignment, but perhaps only when the dynamics of auditory and visual streams are similar. These mechanisms may contribute to correct auditory-visual binding in a busy sensory environment.

  16. Auditory Training and Its Effects upon the Auditory Discrimination and Reading Readiness of Kindergarten Children.

    Science.gov (United States)

    Cullen, Minga Mustard

    The purpose of this investigation was to evaluate the effects of a systematic auditory training program on the auditory discrimination ability and reading readiness of 55 white, middle/upper middle class kindergarten students. Following pretesting with the "Wepman Auditory Discrimination Test,""The Clymer-Barrett Prereading Battery," and the…

  17. Effects of Methylphenidate (Ritalin) on Auditory Performance in Children with Attention and Auditory Processing Disorders.

    Science.gov (United States)

    Tillery, Kim L.; Katz, Jack; Keller, Warren D.

    2000-01-01

    A double-blind, placebo-controlled study examined effects of methylphenidate (Ritalin) on auditory processing in 32 children with both attention deficit hyperactivity disorder and central auditory processing (CAP) disorder. Analyses revealed that Ritalin did not have a significant effect on any of the central auditory processing measures, although…

  18. Thalamic activation modulates the responses of neurons in rat primary auditory cortex: an in vivo intracellular recording study.

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    Lei Han

    Full Text Available Auditory cortical plasticity can be induced through various approaches. The medial geniculate body (MGB of the auditory thalamus gates the ascending auditory inputs to the cortex. The thalamocortical system has been proposed to play a critical role in the responses of the auditory cortex (AC. In the present study, we investigated the cellular mechanism of the cortical activity, adopting an in vivo intracellular recording technique, recording from the primary auditory cortex (AI while presenting an acoustic stimulus to the rat and electrically stimulating its MGB. We found that low-frequency stimuli enhanced the amplitudes of sound-evoked excitatory postsynaptic potentials (EPSPs in AI neurons, whereas high-frequency stimuli depressed these auditory responses. The degree of this modulation depended on the intensities of the train stimuli as well as the intervals between the electrical stimulations and their paired sound stimulations. These findings may have implications regarding the basic mechanisms of MGB activation of auditory cortical plasticity and cortical signal processing.

  19. Central auditory function of deafness genes.

    Science.gov (United States)

    Willaredt, Marc A; Ebbers, Lena; Nothwang, Hans Gerd

    2014-06-01

    The highly variable benefit of hearing devices is a serious challenge in auditory rehabilitation. Various factors contribute to this phenomenon such as the diversity in ear defects, the different extent of auditory nerve hypoplasia, the age of intervention, and cognitive abilities. Recent analyses indicate that, in addition, central auditory functions of deafness genes have to be considered in this context. Since reduced neuronal activity acts as the common denominator in deafness, it is widely assumed that peripheral deafness influences development and function of the central auditory system in a stereotypical manner. However, functional characterization of transgenic mice with mutated deafness genes demonstrated gene-specific abnormalities in the central auditory system as well. A frequent function of deafness genes in the central auditory system is supported by a genome-wide expression study that revealed significant enrichment of these genes in the transcriptome of the auditory brainstem compared to the entire brain. Here, we will summarize current knowledge of the diverse central auditory functions of deafness genes. We furthermore propose the intimately interwoven gene regulatory networks governing development of the otic placode and the hindbrain as a mechanistic explanation for the widespread expression of these genes beyond the cochlea. We conclude that better knowledge of central auditory dysfunction caused by genetic alterations in deafness genes is required. In combination with improved genetic diagnostics becoming currently available through novel sequencing technologies, this information will likely contribute to better outcome prediction of hearing devices.

  20. Perceptual hysteresis in the judgment of auditory pitch shift.

    Science.gov (United States)

    Chambers, Claire; Pressnitzer, Daniel

    2014-07-01

    Perceptual hysteresis can be defined as the enduring influence of the recent past on current perception. Here, hysteresis was investigated in a basic auditory task: pitch comparisons between successive tones. On each trial, listeners were presented with pairs of tones and asked to report the direction of subjective pitch shift, as either "up" or "down." All tones were complexes known as Shepard tones (Shepard, 1964), which comprise several frequency components at octave multiples of a base frequency. The results showed that perceptual judgments were determined both by stimulus-related factors (the interval ratio between the base frequencies within a pair) and by recent context (the intervals in the two previous trials). When tones were presented in ordered sequences, for which the frequency interval between tones was varied in a progressive manner, strong hysteresis was found. In particular, ambiguous stimuli that led to equal probabilities of "up" and "down" responses within a randomized context were almost fully determined within an ordered context. Moreover, hysteresis did not act on the direction of the reported pitch shift, but rather on the perceptual representation of each tone. Thus, hysteresis could be observed within sequences in which listeners varied between "up" and "down" responses, enabling us to largely rule out confounds related to response bias. The strength of the perceptual hysteresis observed suggests that the ongoing context may have a substantial influence on fundamental aspects of auditory perception, such as how we perceive the changes in pitch between successive sounds.

  1. Across-ear stimulus-specific adaptation in the auditory cortex

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    Xinxiu eXu

    2014-07-01

    Full Text Available The ability to detect unexpected or deviant events in natural scenes is critical for survival. In the auditory system, neurons from the midbrain to cortex adapt quickly to repeated stimuli but this adaptation does not fully generalize to other, rare stimuli, a phenomenon called stimulus-specific adaptation (SSA. Most studies of SSA were conducted with pure tones of different frequencies, and it is by now well-established that SSA to tone frequency is strong and robust in auditory cortex. Here we tested SSA in the auditory cortex to the ear of stimulation using broadband noise. We show that cortical neurons adapt specifically to the ear of stimulation, and that the contrast between the responses to stimulation of the same ear when rare and when common depends on the binaural interaction class of the neurons.

  2. Neurological associations in auditory neuropathy spectrum disorder: Results from a tertiary hospital in South India

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    Anjali Lepcha

    2015-01-01

    Full Text Available Aims: To find out the prevalence and types of neurological abnormalities associated in auditory neuropathy spectrum disorder in a large tertiary referral center. Settings and Design: A prospective clinical study was conducted on all patients diagnosed with auditory neuropathy spectrum disorder in the ear, nose, and throat (ENT and neurology departments during a 17-month period. Patients with neurological abnormalities on history and examination were further assessed by a neurologist to determine the type of disorder present. Results: The frequency of auditory neuropathy spectrum disorder was 1.12%. Sixty percent were found to have neurological involvement. This included cerebral palsy in children, peripheral neuropathy (PN, spinocerebellar ataxia, hereditary motor-sensory neuropathy, spastic paresis, and ponto-bulbar palsy. Neurological lesions did not present simultaneously with hearing loss in most patients. Sixty-six percent of patients with auditory neuropathy spectrum disorder were born of consanguineous marriages. Conclusions: There is a high prevalence of neurological lesions in auditory neuropathy spectrum disorder which has to be kept in mind while evaluating such patients. Follow-up and counselling regarding the appearance of neuropathies is therefore important in such patients. A hereditary etiology is indicated in a majority of cases of auditory neuropathy spectrum disorder.

  3. The Experience of Patients with Schizophrenia Treated with Repetitive Transcranial Magnetic Stimulation for Auditory Hallucinations

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    Priya Subramanian

    2013-01-01

    Full Text Available Introduction. Auditory hallucinations are a common symptom experience of individuals with psychotic disorders and are often experienced as persistent, distressing, and disruptive. This case series examined the lived experiences of four individuals treated (successfully or unsuccessfully with low-frequency (1 Hz rTMS for auditory hallucinations. Methods. A phenomenological approach was used and modified to involve some predetermined data structuring to accommodate for expected cognitive impairments of participants and the impact of rTMS on auditory hallucinations. Data on thoughts and feelings in relation to the helpful, unhelpful, and other effects of rTMS on auditory hallucinations, on well-being, functioning, and the immediate environment were collected using semistructured interviews. Results. All four participants noted some improvements in their well-being following treatment and none reported a worsening of their symptoms. Only two participants noted an improvement in the auditory hallucinations and only one of them reported an improvement that was sustained after treatment completion. Conclusion. We suggest that there are useful findings in the study worth further exploration, specifically in relation to the role of an individual’s acceptance and ownership of the illness process in relation to this biomedical intervention. More mixed methods research is required to examine rTMS for auditory hallucinations.

  4. Neurological associations in auditory neuropathy spectrum disorder: Results from a tertiary hospital in South India

    Science.gov (United States)

    Lepcha, Anjali; Chandran, Reni K.; Alexander, Mathew; Agustine, Ann Mary; Thenmozhi, K.; Balraj, Achamma

    2015-01-01

    Aims: To find out the prevalence and types of neurological abnormalities associated in auditory neuropathy spectrum disorder in a large tertiary referral center. Settings and Design: A prospective clinical study was conducted on all patients diagnosed with auditory neuropathy spectrum disorder in the ear, nose, and throat (ENT) and neurology departments during a 17-month period. Patients with neurological abnormalities on history and examination were further assessed by a neurologist to determine the type of disorder present. Results: The frequency of auditory neuropathy spectrum disorder was 1.12%. Sixty percent were found to have neurological involvement. This included cerebral palsy in children, peripheral neuropathy (PN), spinocerebellar ataxia, hereditary motor-sensory neuropathy, spastic paresis, and ponto-bulbar palsy. Neurological lesions did not present simultaneously with hearing loss in most patients. Sixty-six percent of patients with auditory neuropathy spectrum disorder were born of consanguineous marriages. Conclusions: There is a high prevalence of neurological lesions in auditory neuropathy spectrum disorder which has to be kept in mind while evaluating such patients. Follow-up and counselling regarding the appearance of neuropathies is therefore important in such patients. A hereditary etiology is indicated in a majority of cases of auditory neuropathy spectrum disorder. PMID:26019414

  5. Developmental activity variations of DNA polymerase α,δ,ε in mouse forebrains and spleens

    Institute of Scientific and Technical Information of China (English)

    杨荣武; 陆长德

    1995-01-01

    The levels of DNA polymerase α,δ,ε were examined in the neonatal mouse forebrains andspleens.The levels of DNA polymerase α were determined by the difference of polymerase activity in theabsence and the presence of α specific inhibitor,BuPdGTP,or its monoclonal antibody.The levels of DNApolymerase δ were determined in H · A fractions after separating it from the other two enzymes.The levelsof DNA polymerase ε were identified in H · A fractions by the use of α-monoclonal antibody or BuPdGTP.Results showed that in the mouse forebrain DNA polymerase α,δ,ε activities are the highest before birth,decline sharply following birth and are very low on the 8th day and hardly detectable on the 17th day;as forthe mouse spleen,however,DNA polymerase α,δ,ε activities are the lowest at birth,increase rapidly afterbirth and reach their maxima on the 8th day and then decline gradually but remain in higher levels.Theseresults not only prove that DNA polymerase α and δ take part in cell DNA replication but also suggest thatDNA polymerase ε is involved in DNA replication.

  6. Shp2 in forebrain neurons regulates synaptic plasticity, locomotion, and memory formation in mice.

    Science.gov (United States)

    Kusakari, Shinya; Saitow, Fumihito; Ago, Yukio; Shibasaki, Koji; Sato-Hashimoto, Miho; Matsuzaki, Yasunori; Kotani, Takenori; Murata, Yoji; Hirai, Hirokazu; Matsuda, Toshio; Suzuki, Hidenori; Matozaki, Takashi; Ohnishi, Hiroshi

    2015-05-01

    Shp2 (Src homology 2 domain-containing protein tyrosine phosphatase 2) regulates neural cell differentiation. It is also expressed in postmitotic neurons, however, and mutations of Shp2 are associated with clinical syndromes characterized by mental retardation. Here we show that conditional-knockout (cKO) mice lacking Shp2 specifically in postmitotic forebrain neurons manifest abnormal behavior, including hyperactivity. Novelty-induced expression of immediate-early genes and activation of extracellular-signal-regulated kinase (Erk) were attenuated in the cerebral cortex and hippocampus of Shp2 cKO mice, suggestive of reduced neuronal activity. In contrast, ablation of Shp2 enhanced high-K(+)-induced Erk activation in both cultured cortical neurons and synaptosomes, whereas it inhibited that induced by brain-derived growth factor in cultured neurons. Posttetanic potentiation and paired-pulse facilitation were attenuated and enhanced, respectively, in hippocampal slices from Shp2 cKO mice. The mutant mice also manifested transient impairment of memory formation in the Morris water maze. Our data suggest that Shp2 contributes to regulation of Erk activation and synaptic plasticity in postmitotic forebrain neurons and thereby controls locomotor activity and memory formation.

  7. Hierarchical prediction errors in midbrain and basal forebrain during sensory learning.

    Science.gov (United States)

    Iglesias, Sandra; Mathys, Christoph; Brodersen, Kay H; Kasper, Lars; Piccirelli, Marco; den Ouden, Hanneke E M; Stephan, Klaas E

    2013-10-16

    In Bayesian brain theories, hierarchically related prediction errors (PEs) play a central role for predicting sensory inputs and inferring their underlying causes, e.g., the probabilistic structure of the environment and its volatility. Notably, PEs at different hierarchical levels may be encoded by different neuromodulatory transmitters. Here, we tested this possibility in computational fMRI studies of audio-visual learning. Using a hierarchical Bayesian model, we found that low-level PEs about visual stimulus outcome were reflected by widespread activity in visual and supramodal areas but also in the midbrain. In contrast, high-level PEs about stimulus probabilities were encoded by the basal forebrain. These findings were replicated in two groups of healthy volunteers. While our fMRI measures do not reveal the exact neuron types activated in midbrain and basal forebrain, they suggest a dichotomy between neuromodulatory systems, linking dopamine to low-level PEs about stimulus outcome and acetylcholine to more abstract PEs about stimulus probabilities.

  8. Loss of Lrp2 in zebrafish disrupts pronephric tubular clearance but not forebrain development.

    Science.gov (United States)

    Kur, Esther; Christa, Anna; Veth, Kerry N; Gajera, Chandresh R; Andrade-Navarro, Miguel A; Zhang, Jingjing; Willer, Jason R; Gregg, Ronald G; Abdelilah-Seyfried, Salim; Bachmann, Sebastian; Link, Brian A; Hammes, Annette; Willnow, Thomas E

    2011-06-01

    Low-density lipoprotein receptor-related protein 2 (LRP2) is a multifunctional cell surface receptor conserved from nematodes to humans. In mammals, it acts as regulator of sonic hedgehog and bone morphogenetic protein pathways in patterning of the embryonic forebrain and as a clearance receptor in the adult kidney. Little is known about activities of this LRP in other phyla. Here, we extend the functional elucidation of LRP2 to zebrafish as a model organism of receptor (dys)function. We demonstrate that expression of Lrp2 in embryonic and larval fish recapitulates the patterns seen in mammalian brain and kidney. Furthermore, we studied the consequence of receptor deficiencies in lrp2 and in lrp2b, a homologue unique to fish, using ENU mutagenesis or morpholino knockdown. While receptor-deficient zebrafish suffer from overt renal resorption deficiency, their brain development proceeds normally, suggesting evolutionary conservation of receptor functions in pronephric duct clearance but not in patterning of the teleost forebrain.

  9. Fine-Tuning Circadian Rhythms: The Importance of Bmal1 Expression in the Ventral Forebrain

    Science.gov (United States)

    Mieda, Michihiro; Hasegawa, Emi; Kessaris, Nicoletta; Sakurai, Takeshi

    2017-01-01

    Although, the suprachiasmatic nucleus (SCN) of the hypothalamus acts as the central clock in mammals, the circadian expression of clock genes has been demonstrated not only in the SCN, but also in peripheral tissues and brain regions outside the SCN. However, the physiological roles of extra-SCN circadian clocks in the brain remain largely elusive. In response, we generated Nkx2.1-Bmal1−/− mice in which Bmal1, an essential clock component, was genetically deleted specifically in the ventral forebrain, including the preoptic area, nucleus of the diagonal band, and most of the hypothalamus except the SCN. In these mice, as expected, PER2::LUC oscillation was drastically attenuated in the explants of mediobasal hypothalamus, whereas it was maintained in those of the SCN. Although, Nkx2.1-Bmal1−/− mice were rhythmic and nocturnal, they showed altered patterns of locomotor activity during the night in a 12:12-h light:dark cycle and during subjective night in constant darkness. Control mice were more active during the first half than the second half of the dark phase or subjective night, whereas Nkx2.1-Bmal1−/− mice showed the opposite pattern of locomotor activity. Temporal patterns of sleep-wakefulness and feeding also changed accordingly. Such results suggest that along with mechanisms in the SCN, local Bmal1–dependent clocks in the ventral forebrain are critical for generating precise temporal patterns of circadian behaviors.

  10. Conservation of spatial memory function in the pallial forebrain of reptiles and ray-finned fishes.

    Science.gov (United States)

    Rodríguez, Fernando; López, J Carlos; Vargas, J Pedro; Gómez, Yolanda; Broglio, Cristina; Salas, Cosme

    2002-04-01

    The hippocampus of mammals and birds is critical for spatial memory. Neuroanatomical evidence indicates that the medial cortex (MC) of reptiles and the lateral pallium (LP) of ray-finned fishes could be homologous to the hippocampus of mammals and birds. In this work, we studied the effects of lesions to the MC of turtles and to the LP of goldfish in spatial memory. Lesioned animals were trained in place, and cue maze tasks and crucial probe and transfer tests were performed. In experiment 1, MC-lesioned turtles in the place task failed to locate the goal during trials in which new start positions were used, whereas sham animals navigated directly to the goal independently of start location. In contrast, no deficit was observed in cue learning. In experiment 2, LP lesion produced a dramatic impairment in goldfish trained in the place task, whereas medial and dorsal pallium lesions did not decrease accuracy. In addition, none of these pallial lesions produced deficits in cue learning. These results indicate that lesions to the MC of turtles and to the LP of goldfish, like hippocampal lesions in mammals and birds, selectively impair map-like memory representations of the environmental space. Thus, the forebrain structures of reptiles and teleost fish neuroanatomically equivalent to the mammalian and avian hippocampus also share a central role in spatial cognition. Present results suggest that the presence of a hippocampus-dependent spatial memory system is a primitive feature of the vertebrate forebrain that has been conserved through evolution.

  11. Basal forebrain neurons suppress amygdala kindling via cortical but not hippocampal cholinergic projections in rats.

    Science.gov (United States)

    Ferencz, I; Leanza, G; Nanobashvili, A; Kokaia, M; Lindvall, O

    2000-06-01

    Intraventricular administration of the immunotoxin 192 IgG-saporin in rats has been shown to cause a selective loss of cholinergic afferents to the hippocampus and cortical areas, and to facilitate seizure development in hippocampal kindling. Here we demonstrate that this lesion also accelerates seizure progression when kindling is induced by electrical stimulations in the amygdala. However, whereas intraventricular 192 IgG-saporin facilitated the development of the initial stages of hippocampal kindling, the same lesion promoted the late stages of amygdala kindling. To explore the role of various parts of the basal forebrain cholinergic system in amygdala kindling, selective lesions of the cholinergic projections to either hippocampus or cortex were produced by intraparenchymal injections of 192 IgG-saporin into medial septum/vertical limb of the diagonal band or nucleus basalis, respectively. Cholinergic denervation of the cortical regions caused acceleration of amygdala kindling closely resembling that observed after the more widespread lesion induced by intraventricular 192 IgG-saporin. In contrast, removal of the cholinergic input to the hippocampus had no effect on the development of amygdala kindling. These data indicate that basal forebrain cholinergic neurons suppress kindling elicited from amygdala, and that this dampening effect is mediated via cortical but not hippocampal projections.

  12. Evolutionary adaptations for the temporal processing of natural sounds by the anuran peripheral auditory system.

    Science.gov (United States)

    Schrode, Katrina M; Bee, Mark A

    2015-03-01

    Sensory systems function most efficiently when processing natural stimuli, such as vocalizations, and it is thought that this reflects evolutionary adaptation. Among the best-described examples of evolutionary adaptation in the auditory system are the frequent matches between spectral tuning in both the peripheral and central auditory systems of anurans (frogs and toads) and the frequency spectra of conspecific calls. Tuning to the temporal properties of conspecific calls is less well established, and in anurans has so far been documented only in the central auditory system. Using auditory-evoked potentials, we asked whether there are species-specific or sex-specific adaptations of the auditory systems of gray treefrogs (Hyla chrysoscelis) and green treefrogs (H. cinerea) to the temporal modulations present in conspecific calls. Modulation rate transfer functions (MRTFs) constructed from auditory steady-state responses revealed that each species was more sensitive than the other to the modulation rates typical of conspecific advertisement calls. In addition, auditory brainstem responses (ABRs) to paired clicks indicated relatively better temporal resolution in green treefrogs, which could represent an adaptation to the faster modulation rates present in the calls of this species. MRTFs and recovery of ABRs to paired clicks were generally similar between the sexes, and we found no evidence that males were more sensitive than females to the temporal modulation patterns characteristic of the aggressive calls used in male-male competition. Together, our results suggest that efficient processing of the temporal properties of behaviorally relevant sounds begins at potentially very early stages of the anuran auditory system that include the periphery.

  13. Sustained Cortical and Subcortical Measures of Auditory and Visual Plasticity following Short-Term Perceptual Learning.

    Science.gov (United States)

    Lau, Bonnie K; Ruggles, Dorea R; Katyal, Sucharit; Engel, Stephen A; Oxenham, Andrew J

    2017-01-01

    Short-term training can lead to improvements in behavioral discrimination of auditory and visual stimuli, as well as enhanced EEG responses to those stimuli. In the auditory domain, fluency with tonal languages and musical training has been associated with long-term cortical and subcortical plasticity, but less is known about the effects of shorter-term training. This study combined electroencephalography (EEG) and behavioral measures to investigate short-term learning and neural plasticity in both auditory and visual domains. Forty adult participants were divided into four groups. Three groups trained on one of three tasks, involving discrimination of auditory fundamental frequency (F0), auditory amplitude modulation rate (AM), or visual orientation (VIS). The fourth (control) group received no training. Pre- and post-training tests, as well as retention tests 30 days after training, involved behavioral discrimination thresholds, steady-state visually evoked potentials (SSVEP) to the flicker frequencies of visual stimuli, and auditory envelope-following responses simultaneously evoked and measured in response to rapid stimulus F0 (EFR), thought to reflect subcortical generators, and slow amplitude modulation (ASSR), thought to reflect cortical generators. Enhancement of the ASSR was observed in both auditory-trained groups, not specific to the AM-trained group, whereas enhancement of the SSVEP was found only in the visually-trained group. No evidence was found for changes in the EFR. The results suggest that some aspects of neural plasticity can develop rapidly and may generalize across tasks but not across modalities. Behaviorally, the pattern of learning was complex, with significant cross-task and cross-modal learning effects.

  14. Noise-induced cell death in the mouse medial geniculate body and primary auditory cortex.

    Science.gov (United States)

    Basta, Dietmar; Tzschentke, Barbara; Ernst, Arne

    Noise-induced effects within the inner ear have been well investigated for several years. However, this peripheral damage cannot fully explain the audiological symptoms in noise-induced hearing loss (NIHL), e.g. tinnitus, recruitment, reduced speech intelligibility, hyperacusis. There are few reports on central noise effects. Noise can induce an apoptosis of neuronal tissue within the lower auditory pathway. Higher auditory structures (e.g. medial geniculate body, auditory cortex) are characterized by metabolic changes after noise exposure. However, little is known about the microstructural changes of the higher auditory pathway after noise exposure. The present paper was therefore aimed at investigating the cell density in the medial geniculate body (MGB) and the primary auditory cortex (AI) after noise exposure. Normal hearing mice were exposed to noise (10 kHz center frequency at 115 dB SPL for 3 h) at the age of 21 days under anesthesia (Ketamin/Rompun, 10:1). After 1 week, auditory brainstem response recordings (ABR) were performed in noise exposed and normal hearing animals. After fixation, the brain was microdissected and stained (Kluever-Barrera). The cell density in the MGB subdivisions and the AI were determined by counting the cells within a grid. Noise-exposed animals showed a significant ABR threshold shift over the whole frequency range. Cell density was significantly reduced in all subdivisions of the MGB and in layers IV-VI of AI. The present findings demonstrate a significant noise-induced change of the neuronal cytoarchitecture in central key areas of auditory processing. These changes could contribute to the complex psychoacoustic symptoms after NIHL.

  15. Noise Trauma Induced Plastic Changes in Brain Regions outside the Classical Auditory Pathway

    Science.gov (United States)

    Chen, Guang-Di; Sheppard, Adam; Salvi, Richard

    2017-01-01

    The effects of intense noise exposure on the classical auditory pathway have been extensively investigated; however, little is known about the effects of noise-induced hearing loss on non-classical auditory areas in the brain such as the lateral amygdala (LA) and striatum (Str). To address this issue, we compared the noise-induced changes in spontaneous and tone-evoked responses from multiunit clusters (MUC) in the LA and Str with those seen in auditory cortex (AC). High-frequency octave band noise (10–20 kHz) and narrow band noise (16–20 kHz) induced permanent thresho ld shifts (PTS) at high-frequencies within and above the noise band but not at low frequencies. While the noise trauma significantly elevated spontaneous discharge rate (SR) in the AC, SRs in the LA and Str were only slightly increased across all frequencies. The high-frequency noise trauma affected tone-evoked firing rates in frequency and time dependent manner and the changes appeared to be related to severity of noise trauma. In the LA, tone-evoked firing rates were reduced at the high-frequencies (trauma area) whereas firing rates were enhanced at the low-frequencies or at the edge-frequency dependent on severity of hearing loss at the high frequencies. The firing rate temporal profile changed from a broad plateau to one sharp, delayed peak. In the AC, tone-evoked firing rates were depressed at high frequencies and enhanced at the low frequencies while the firing rate temporal profiles became substantially broader. In contrast, firing rates in the Str were generally decreased and firing rate temporal profiles become more phasic and less prolonged. The altered firing rate and pattern at low frequencies induced by high frequency hearing loss could have perceptual consequences. The tone-evoked hyperactivity in low-frequency MUC could manifest as hyperacusis whereas the discharge pattern changes could affect temporal resolution and integration. PMID:26701290

  16. Temporal Integration of Auditory Stimulation and Binocular Disparity Signals

    Directory of Open Access Journals (Sweden)

    Marina Zannoli

    2011-10-01

    Full Text Available Several studies using visual objects defined by luminance have reported that the auditory event must be presented 30 to 40 ms after the visual stimulus to perceive audiovisual synchrony. In the present study, we used visual objects defined only by their binocular disparity. We measured the optimal latency between visual and auditory stimuli for the perception of synchrony using a method introduced by Moutoussis & Zeki (1997. Visual stimuli were defined either by luminance and disparity or by disparity only. They moved either back and forth between 6 and 12 arcmin or from left to right at a constant disparity of 9 arcmin. This visual modulation was presented together with an amplitude-modulated 500 Hz tone. Both modulations were sinusoidal (frequency: 0.7 Hz. We found no difference between 2D and 3D motion for luminance stimuli: a 40 ms auditory lag was necessary for perceived synchrony. Surprisingly, even though stereopsis is often thought to be slow, we found a similar optimal latency in the disparity 3D motion condition (55 ms. However, when participants had to judge simultaneity for disparity 2D motion stimuli, it led to larger latencies (170 ms, suggesting that stereo motion detectors are poorly suited to track 2D motion.

  17. Development of auditory-vocal perceptual skills in songbirds.

    Directory of Open Access Journals (Sweden)

    Vanessa C Miller-Sims

    Full Text Available Songbirds are one of the few groups of animals that learn the sounds used for vocal communication during development. Like humans, songbirds memorize vocal sounds based on auditory experience with vocalizations of adult "tutors", and then use auditory feedback of self-produced vocalizations to gradually match their motor output to the memory of tutor sounds. In humans, investigations of early vocal learning have focused mainly on perceptual skills of infants, whereas studies of songbirds have focused on measures of vocal production. In order to fully exploit songbirds as a model for human speech, understand the neural basis of learned vocal behavior, and investigate links between vocal perception and production, studies of songbirds must examine both behavioral measures of perception and neural measures of discrimination during development. Here we used behavioral and electrophysiological assays of the ability of songbirds to distinguish vocal calls of varying frequencies at different stages of vocal learning. The results show that neural tuning in auditory cortex mirrors behavioral improvements in the ability to make perceptual distinctions of vocal calls as birds are engaged in vocal learning. Thus, separate measures of neural discrimination and behavioral perception yielded highly similar trends during the course of vocal development. The timing of this improvement in the ability to distinguish vocal sounds correlates with our previous work showing substantial refinement of axonal connectivity in cortico-basal ganglia pathways necessary for vocal learning.

  18. Auditory Neural Prostheses – A Window to the Future

    Directory of Open Access Journals (Sweden)

    Mohan Kameshwaran

    2015-06-01

    Full Text Available Hearing loss is one of the commonest congenital anomalies to affect children world-over. The incidence of congenital hearing loss is more pronounced in developing countries like the Indian sub-continent, especially with the problems of consanguinity. Hearing loss is a double tragedy, as it leads to not only deafness but also language deprivation. However, hearing loss is the only truly remediable handicap, due to remarkable advances in biomedical engineering and surgical techniques. Auditory neural prostheses help to augment or restore hearing by integration of an external circuitry with the peripheral hearing apparatus and the central circuitry of the brain. A cochlear implant (CI is a surgically implantable device that helps restore hearing in patients with severe-profound hearing loss, unresponsive to amplification by conventional hearing aids. CIs are electronic devices designed to detect mechanical sound energy and convert it into electrical signals that can be delivered to the coch­lear nerve, bypassing the damaged hair cells of the coch­lea. The only true prerequisite is an intact auditory nerve. The emphasis is on implantation as early as possible to maximize speech understanding and perception. Bilateral CI has significant benefits which include improved speech perception in noisy environments and improved sound localization. Presently, the indications for CI have widened and these expanded indications for implantation are related to age, additional handicaps, residual hearing, and special etiologies of deafness. Combined electric and acoustic stimulation (EAS / hybrid device is designed for individuals with binaural low-frequency hearing and severe-to-profound high-frequency hearing loss. Auditory brainstem implantation (ABI is a safe and effective means of hearing rehabilitation in patients with retrocochlear disorders, such as neurofibromatosis type 2 (NF2 or congenital cochlear nerve aplasia, wherein the cochlear nerve is damaged

  19. Development of auditory-vocal perceptual skills in songbirds.

    Science.gov (United States)

    Miller-Sims, Vanessa C; Bottjer, Sarah W

    2012-01-01

    Songbirds are one of the few groups of animals that learn the sounds used for vocal communication during development. Like humans, songbirds memorize vocal sounds based on auditory experience with vocalizations of adult "tutors", and then use auditory feedback of self-produced vocalizations to gradually match their motor output to the memory of tutor sounds. In humans, investigations of early vocal learning have focused mainly on perceptual skills of infants, whereas studies of songbirds have focused on measures of vocal production. In order to fully exploit songbirds as a model for human speech, understand the neural basis of learned vocal behavior, and investigate links between vocal perception and production, studies of songbirds must examine both behavioral measures of perception and neural measures of discrimination during development. Here we used behavioral and electrophysiological assays of the ability of songbirds to distinguish vocal calls of varying frequencies at different stages of vocal learning. The results show that neural tuning in auditory cortex mirrors behavioral improvements in the ability to make perceptual distinctions of vocal calls as birds are engaged in vocal learning. Thus, separate measures of neural discrimination and behavioral perception yielded highly similar trends during the course of vocal development. The timing of this improvement in the ability to distinguish vocal sounds correlates with our previous work showing substantial refinement of axonal connectivity in cortico-basal ganglia pathways necessary for vocal learning.

  20. Mismatch responses in the awake rat: evidence from epidural recordings of auditory cortical fields.

    Directory of Open Access Journals (Sweden)

    Fabienne Jung

    Full Text Available Detecting sudden environmental changes is crucial for the survival of humans and animals. In the human auditory system the mismatch negativity (MMN, a component of auditory evoked potentials (AEPs, reflects the violation of predictable stimulus regularities, established by the previous auditory sequence. Given the considerable potentiality of the MMN for clinical applications, establishing valid animal models that allow for detailed investigation of its neurophysiological mechanisms is important. Rodent studies, so far almost exclusively under anesthesia, have not provided decisive evidence whether an MMN analogue exists in rats. This may be due to several factors, including the effect of anesthesia. We therefore used epidural recordings in awake black hooded rats, from two auditory cortical areas in both hemispheres, and with bandpass filtered noise stimuli that were optimized in frequency and duration for eliciting MMN in rats. Using a classical oddball paradigm with frequency deviants, we detected mismatch responses at all four electrodes in primary and secondary auditory cortex, with morphological and functional properties similar to those known in humans, i.e., large amplitude biphasic differences that increased in amplitude with decreasing deviant probability. These mismatch responses significantly diminished in a control condition that removed the predictive context while controlling for presentation rate of the deviants. While our present study does not allow for disambiguating precisely the relative contribution of adaptation and prediction error processing to the observed mismatch responses, it demonstrates that MMN-like potentials can be obtained in awake and unrestrained rats.

  1. Auditory Perception, Suprasegmental Speech Processing, and Vocabulary Development in Chinese Preschoolers.

    Science.gov (United States)

    Wang, Hsiao-Lan S; Chen, I-Chen; Chiang, Chun-Han; Lai, Ying-Hui; Tsao, Yu

    2016-10-01

    The current study examined the associations between basic auditory perception, speech prosodic processing, and vocabulary development in Chinese kindergartners, specifically, whether early basic auditory perception may be related to linguistic prosodic processing in Chinese Mandarin vocabulary acquisition. A series of language, auditory, and linguistic prosodic tests were given to 100 preschool children who had not yet learned how to read Chinese characters. The results suggested that lexical tone sensitivity and intonation production were significantly correlated with children's general vocabulary abilities. In particular, tone awareness was associated with comprehensive language development, whereas intonation production was associated with both comprehensive and expressive language development. Regression analyses revealed that tone sensitivity accounted for 36% of the unique variance in vocabulary development, whereas intonation production accounted for 6% of the variance in vocabulary development. Moreover, auditory frequency discrimination was significantly correlated with lexical tone sensitivity, syllable duration discrimination, and intonation production in Mandarin Chinese. Also it provided significant contributions to tone sensitivity and intonation production. Auditory frequency discrimination may indirectly affect early vocabulary development through Chinese speech prosody.

  2. Tonotopic organization of auditory receptors of the bushcricket pholidoptera griseoaptera (Tettigoniidae, decticinae)

    Science.gov (United States)

    Stolting; Stumpner

    1998-11-01

    The peripheral and central tonotopy of auditory receptors of the bushcricket Pholidoptera griseoaptera is described. Out of 24 auditory receptor cells of the crista acustica 18 were identified by single-cell recordings in the prothoracic ganglion and complete staining with neurobiotin. Proximal receptor cells of the crista acustica were most sensitive to 6 kHz, with medial cells being sensitive to 20-30 kHz, whereas distal cells were most sensitive to frequencies higher than 50 kHz. Projection areas within the auditory neuropile in the prothoracic ganglion were to- notopically arranged. Proximal cells projected anteriorly, medial cells ventrally and posteriorly, and distal cells to more dorsal regions. Identified receptor cells revealed an interindividual variability of tuning and central projections. Receptor cells from the intermediate organ of a bushcricket were identified for the first time. Receptors of the distal intermediate organ were broadly tuned and less sensitive than those of the crista acustica. Receptor cells of the proximal intermediate organ were most sensitive to frequencies below 10 kHz. They projected in anterior portions of the auditory neuropile, whereas cells of the distal intermediate organ had terminations spread over almost the whole auditory neuropile.

  3. Morphological and physiological regeneration in the auditory system of adult Mecopoda elongata (Orthoptera: Tettigoniidae).

    Science.gov (United States)

    Krüger, Silke; Butler, Casey S; Lakes-Harlan, Reinhard

    2011-02-01

    Orthopterans are suitable model organisms for investigations of regeneration mechanisms in the auditory system. Regeneration has been described in the auditory systems of locusts (Caelifera) and of crickets (Ensifera). In this study, we comparatively investigate the neural regeneration in the auditory system in the bush cricket Mecopoda elongata. A crushing of the tympanal nerve in the foreleg of M. elongata results in a loss of auditory information transfer. Physiological recordings of the tympanal nerve suggest outgrowing fibers 5 days after crushing. An anatomical regeneration of the fibers within the central nervous system starts 10 days after crushing. The neuronal projection reaches the target area at day 20. Threshold values to low frequency airborne sound remain high after crushing, indicating a lower regeneration capability of this group of fibers. However, within the central target area the low frequency areas are also innervated. Recordings of auditory interneurons show that the regenerating fibers form new functional connections starting at day 20 after crushing.

  4. Use of transcranial direct current stimulation for the treatment of auditory hallucinations of schizophrenia – a systematic review

    Science.gov (United States)

    Pondé, Pedro H; de Sena, Eduardo P; Camprodon, Joan A; de Araújo, Arão Nogueira; Neto, Mário F; DiBiasi, Melany; Baptista, Abrahão Fontes; Moura, Lidia MVR; Cosmo, Camila

    2017-01-01

    Introduction Auditory hallucinations are defined as experiences of auditory perceptions in the absence of a provoking external stimulus. They are the most prevalent symptoms of schizophrenia with high capacity for chronicity and refractoriness during the course of disease. The transcranial direct current stimulation (tDCS) – a safe, portable, and inexpensive neuromodulation technique – has emerged as a promising treatment for the management of auditory hallucinations. Objective The aim of this study is to analyze the level of evidence in the literature available for the use of tDCS as a treatment for auditory hallucinations in schizophrenia. Methods A systematic review was performed, searching in the main electronic databases including the Cochrane Library and MEDLINE/PubMed. The searches were performed by combining descriptors, applying terms of the Medical Subject Headings (MeSH) of Descriptors of Health Sciences and descriptors contractions. PRISMA protocol was used as a guide and the terms used were the clinical outcomes (“Schizophrenia” OR “Auditory Hallucinations” OR “Auditory Verbal Hallucinations” OR “Psychosis”) searched together (“AND”) with interventions (“transcranial Direct Current Stimulation” OR “tDCS” OR “Brain Polarization”). Results Six randomized controlled trials that evaluated the effects of tDCS on the severity of auditory hallucinations in schizophrenic patients were selected. Analysis of the clinical results of these studies pointed toward incongruence in the information with regard to the therapeutic use of tDCS with a view to reducing the severity of auditory hallucinations in schizophrenia. Only three studies revealed a therapeutic benefit, manifested by reductions in severity and frequency of auditory verbal hallucinations in schizophrenic patients. Conclusion Although tDCS has shown promising results in reducing the severity of auditory hallucinations in schizophrenic patients, this technique cannot

  5. Auditory hallucinations in nonverbal quadriplegics.

    Science.gov (United States)

    Hamilton, J

    1985-11-01

    When a system for communicating with nonverbal, quadriplegic, institutionalized residents was developed, it was discovered that many were experiencing auditory hallucinations. Nine cases are presented in this study. The "voices" described have many similar characteristics, the primary one being that they give authoritarian commands that tell the residents how to behave and to which the residents feel compelled to respond. Both the relationship of this phenomenon to the theoretical work of Julian Jaynes and its effect on the lives of the residents are discussed.

  6. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  7. Developmental stress impairs performance on an association task in male and female songbirds, but impairs auditory learning in females only.

    Science.gov (United States)

    Farrell, Tara M; Morgan, Amanda; MacDougall-Shackleton, Scott A

    2016-01-01

    In songbirds, early-life environments critically shape song development. Many studies have demonstrated that developmental stress impairs song learning and the development of song-control regions of the brain in males. However, song has evolved through signaller-receiver networks and the effect stress has on the ability to receive auditory signals is equally important, especially for females who use song as an indicator of mate quality. Female song preferences have been the metric used to evaluate how developmental stress affects auditory learning, but preferences are shaped by many non-cognitive factors and preclude the evaluation of auditory learning abilities in males. To determine whether developmental stress specifically affects auditory learning in both sexes, we subjected juvenile European starlings, Sturnus vulgaris, to either an ad libitum or an unpredictable food supply treatment from 35 to 115 days of age. In adulthood, we assessed learning of both auditory and visual discrimination tasks. Females reared in the experimental group were slower than females in the control group to acquire a relative frequency auditory task, and slower than their male counterparts to acquire an absolute frequency auditory task. There was no difference in auditory performance between treatment groups for males. However, on the colour association task, birds from the experimental group committed more errors per trial than control birds. There was no correlation in performance across the cognitive tasks. Developmental stress did not affect all cognitive processes equally across the sexes. Our results suggest that the male auditory system may be more robust to developmental stress than that of females.

  8. Mapping tonotopy in human auditory cortex

    NARCIS (Netherlands)

    van Dijk, Pim; Langers, Dave R M; Moore, BCJ; Patterson, RD; Winter, IM; Carlyon, RP; Gockel, HE

    2013-01-01

    Tonotopy is arguably the most prominent organizational principle in the auditory pathway. Nevertheless, the layout of tonotopic maps in humans is still debated. We present neuroimaging data that robustly identify multiple tonotopic maps in the bilateral auditory cortex. In contrast with some earlier

  9. Bilateral duplication of the internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Weon, Young Cheol; Kim, Jae Hyoung; Choi, Sung Kyu [Seoul National University College of Medicine, Department of Radiology, Seoul National University Bundang Hospital, Seongnam-si (Korea); Koo, Ja-Won [Seoul National University College of Medicine, Department of Otolaryngology, Seoul National University Bundang Hospital, Seongnam-si (Korea)

    2007-10-15

    Duplication of the internal auditory canal is an extremely rare temporal bone anomaly that is believed to result from aplasia or hypoplasia of the vestibulocochlear nerve. We report bilateral duplication of the internal auditory canal in a 28-month-old boy with developmental delay and sensorineural hearing loss. (orig.)

  10. Primary Auditory Cortex Regulates Threat Memory Specificity

    Science.gov (United States)

    Wigestrand, Mattis B.; Schiff, Hillary C.; Fyhn, Marianne; LeDoux, Joseph E.; Sears, Robert M.

    2017-01-01

    Distinguishing threatening from nonthreatening stimuli is essential for survival and stimulus generalization is a hallmark of anxiety disorders. While auditory threat learning produces long-lasting plasticity in primary auditory cortex (Au1), it is not clear whether such Au1 plasticity regulates memory specificity or generalization. We used…

  11. Further Evidence of Auditory Extinction in Aphasia

    Science.gov (United States)

    Marshall, Rebecca Shisler; Basilakos, Alexandra; Love-Myers, Kim

    2013-01-01

    Purpose: Preliminary research ( Shisler, 2005) suggests that auditory extinction in individuals with aphasia (IWA) may be connected to binding and attention. In this study, the authors expanded on previous findings on auditory extinction to determine the source of extinction deficits in IWA. Method: Seventeen IWA (M[subscript age] = 53.19 years)…

  12. Auditory Processing Disorder and Foreign Language Acquisition

    Science.gov (United States)

    Veselovska, Ganna

    2015-01-01

    This article aims at exploring various strategies for coping with the auditory processing disorder in the light of foreign language acquisition. The techniques relevant to dealing with the auditory processing disorder can be attributed to environmental and compensatory approaches. The environmental one involves actions directed at creating a…

  13. Neural processing of auditory signals and modular neural control for sound tropism of walking machines

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Pasemann, Frank; Fischer, Joern;

    2005-01-01

    The specialized hairs and slit sensillae of spiders (Cupiennius salei) can sense the airflow and auditory signals in a low-frequency range. They provide the sensor information for reactive behavior, like e.g. capturing a prey. In analogy, in this paper a setup is described where two microphones a...

  14. Auditory Temporal Order Discrimination and Backward Recognition Masking in Adults with Dyslexia

    Science.gov (United States)

    Griffiths, Yvonne M.; Hill, Nicholas I.; Bailey, Peter J.; Snowling, Margaret J.

    2003-01-01

    The ability of 20 adult dyslexic readers to extract frequency information from successive tone pairs was compared with that of IQ-matched controls using temporal order discrimination and auditory backward recognition masking (ABRM) tasks. In both paradigms, the interstimulus interval (ISI) between tones in a pair was either short (20 ms) or long…

  15. Bedside Evaluation of the Functional Organization of the Auditory Cortex in Patients with Disorders of Consciousness.

    Science.gov (United States)

    Henriques, Julie; Pazart, Lionel; Grigoryeva, Lyudmila; Muzard, Emelyne; Beaussant, Yvan; Haffen, Emmanuel; Moulin, Thierry; Aubry, Régis; Ortega, Juan-Pablo; Gabriel, Damien

    2016-01-01

    To measure the level of residual cognitive function in patients with disorders of consciousness, the use of electrophysiological and neuroimaging protocols of increasing complexity is recommended. This work presents an EEG-based method capable of assessing at an individual level the integrity of the auditory cortex at the bedside of patients and can be seen as the first cortical stage of this hierarchical approach. The method is based on two features: first, the possibility of automatically detecting the presence of a N100 wave and second, in showing evidence of frequency processing in the auditory cortex with a machine learning based classification of the EEG signals associated with different frequencies and auditory stimulation modalities. In the control group of twelve healthy volunteers, cortical frequency processing was clearly demonstrated. EEG recordings from two patients with disorders of consciousness showed evidence of partially preserved cortical processing in the first patient and none in the second patient. From these results, it appears that the classification method presented here reliably detects signal differences in the encoding of frequencies and is a useful tool in the evaluation of the integrity of the auditory cortex. Even though the classification method presented in this work was designed for patients with disorders of consciousness, it can also be applied to other pathological populations.

  16. Sparse representation of sounds in the unanesthetized auditory cortex.

    Directory of Open Access Journals (Sweden)

    Tomás Hromádka

    2008-01-01

    Full Text Available How do neuronal populations in the auditory cortex represent acoustic stimuli? Although sound-evoked neural responses in the anesthetized auditory cortex are mainly transient, recent experiments in the unanesthetized preparation have emphasized subpopulations with other response properties. To quantify the relative contributions of these different subpopulations in the awake preparation, we have estimated the representation of sounds across the neuronal population using a representative ensemble of stimuli. We used cell-attached recording with a glass electrode, a method for which single-unit isolation does not depend on neuronal activity, to quantify the fraction of neurons engaged by acoustic stimuli (tones, frequency modulated sweeps, white-noise bursts, and natural stimuli in the primary auditory cortex of awake head-fixed rats. We find that the population response is sparse, with stimuli typically eliciting high firing rates (>20 spikes/second in less than 5% of neurons at any instant. Some neurons had very low spontaneous firing rates (<0.01 spikes/second. At the other extreme, some neurons had driven rates in excess of 50 spikes/second. Interestingly, the overall population response was well described by a lognormal distribution, rather than the exponential distribution that is often reported. Our results represent, to our knowledge, the first quantitative evidence for sparse representations of sounds in the unanesthetized auditory cortex. Our results are compatible with a model in which most neurons are silent much of the time, and in which representations are composed of small dynamic subsets of highly active neurons.

  17. EEG signatures accompanying auditory figure-ground segregation.

    Science.gov (United States)

    Tóth, Brigitta; Kocsis, Zsuzsanna; Háden, Gábor P; Szerafin, Ágnes; Shinn-Cunningham, Barbara G; Winkler, István

    2016-11-01

    In everyday acoustic scenes, figure-ground segregation typically requires one to group together sound elements over both time and frequency. Electroencephalogram was recorded while listeners detected repeating tonal complexes composed of a random set of pure tones within stimuli consisting of randomly varying tonal elements. The repeating pattern was perceived as a figure over the randomly changing background. It was found that detection performance improved both as the number of pure tones making up each repeated complex (figure coherence) increased, and as the number of repeated complexes (duration) increased - i.e., detection was easier when either the spectral or temporal structure of the figure was enhanced. Figure detection was accompanied by the elicitation of the object related negativity (ORN) and the P400 event-related potentials (ERPs), which have been previously shown to be evoked by the presence of two concurrent sounds. Both ERP components had generators within and outside of auditory cortex. The amplitudes of the ORN and the P400 increased with both figure coherence and figure duration. However, only the P400 amplitude correlated with detection performance. These results suggest that 1) the ORN and P400 reflect processes involved in detecting the emergence of a new auditory object in the presence of other concurrent auditory objects; 2) the ORN corresponds to the likelihood of the presence of two or more concurrent sound objects, whereas the P400 reflects the perceptual recognition of the presence of multiple auditory objects and/or preparation for reporting the detection of a target object.

  18. Similar structural dimensions in bushcricket auditory organs in spite of different foreleg size: consequences for auditory tuning.

    Science.gov (United States)

    Rössler, W; Kalmring, K

    1994-11-01

    The bushcricket species Decticus albifrons, Decticus verrucivorus and Pholidoptera griseoaptera (Tettigoniidae) belong to the same subfamily (Decticinae) but differ significantly in body size. In spite of the great differences in the dimensions of the forelegs, where the auditory organs are located, the most sensitive range of the hearing threshold lies between 6 and 25 kHz in each case. Only in the frequency range from 2 to 5 kHz and above 25 kHz, significant differences are present. The anatomy of the auditory receptor organs was compared quantitatively, using the techniques of semi-thin sectioning and computer-guided morphometry. The overall number of scolopidia and the length of the crista acustica differs in the three species, but the relative distribution of scolopidia along the crista acustica is very similar. Additionally, the scolopidia and their attachment structures (tectorial membrane, dorsal tracheal wall, cap cells) are of equal size at equivalent relative positions along the crista acustica. The results indicate that the constant relations and dimensions of corresponding structures within the cristae acusticae of the three species are responsible for the similarities in the tuning of the auditory thresholds.

  19. Speech perception as complex auditory categorization

    Science.gov (United States)

    Holt, Lori L.

    2002-05-01

    Despite a long and rich history of categorization research in cognitive psychology, very little work has addressed the issue of complex auditory category formation. This is especially unfortunate because the general underlying cognitive and perceptual mechanisms that guide auditory category formation are of great importance to understanding speech perception. I will discuss a new methodological approach to examining complex auditory category formation that specifically addresses issues relevant to speech perception. This approach utilizes novel nonspeech sound stimuli to gain full experimental control over listeners' history of experience. As such, the course of learning is readily measurable. Results from this methodology indicate that the structure and formation of auditory categories are a function of the statistical input distributions of sound that listeners hear, aspects of the operating characteristics of the auditory system, and characteristics of the perceptual categorization system. These results have important implications for phonetic acquisition and speech perception.

  20. The basal forebrain cholinergic system in aging and dementia : Rescuing cholinergic neurons from neurotoxic amyloid-beta 42 with memantine

    NARCIS (Netherlands)

    Nyakas, Csaba; Granic, Ivica; Halmy, Laszlo G.; Banerjee, Pradeep; Luiten, Paul G. M.

    2011-01-01

    The dysfunction and loss of basal forebrain cholinergic neurons and their cortical projections are among the earliest pathological events in the pathogenesis of Alzheimer's disease (AD). The evidence pointing to cholinergic impairments come from studies that report a decline in the activity of choli

  1. DIFFERENTIAL FOS-PROTEIN INDUCTION IN RAT FOREBRAIN REGIONS AFTER ACUTE AND LONG-TERM HALOPERIDOL AND CLOZAPINE TREATMENT

    NARCIS (Netherlands)

    SEBENS, JB; KOCH, T; TERHORST, GJ; KORF, J

    1995-01-01

    Both acute and long-term effects of haloperidol and clozapine on Fos-like immunoreactive nuclei in several rat forebrain areas were quantified. Rats were treated with saline (1 ml/kg.day, control), haloperidol (1 mg/kg.day) and clozapine (20 mg/kg.day) i.p. for 21 days. Two hours before perfusion fi

  2. Distribution of neurotensin/neuromedin N mRNA in rat forebrain: Unexpected abundance in hippocampus and subiculum

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, M.J.; Miller, M.A.; Dorsa, D.M.; Bullock, B.P.; Helloni, R.H. Jr.; Dobner, P.R.; Leeman, S.E. (Univ. of Massachusetts Medical Center, Worcester (USA))

    1989-07-01

    The authors have used in situ hybridization to determine the regional distribution of mRNA encoding the neurotensin/neuromedin N (NT/N) precursor in the forebrain of the adult male rat. Cells containing NT/N mRNA are widely distributed in the forebrain. These areas include the septum, bed nucleus of the stria terminalis, preoptic area, hypothalamus, amygdala, accumbens nucleus, caudate-putamen, and piriform and retrosplenial cortex. In general, the regional distribution of NT/N mRNA corresponds to the previously determined distribution of neurotensin-immunoreactive cell bodies; however, several notable exceptions were observed. The most striking difference occurs specifically in the CA1 region of the hippocampus, where intense labeling is associated with the pyramidal cell layer despite the reported absence of neurotensin-immunoreactive cells in this region. A second major discrepancy between NT/N mRNA abundance and neurotensin-immunoreactivity occurs in the intensely labeled subiculum, a region that contains only scattered neurotensin-immunoreactive cells in the adult. These results suggest that, in specific regions of the forebrain, NT/N precursor is processed to yield products other than neurotensin. In addition, these results provide an anatomical basis for studying the physiological regulation of NT/N mRNA levels in the forebrain.

  3. Lhx2 and Lhx9 determine neuronal differentiation and compartition in the caudal forebrain by regulating Wnt signaling.

    Directory of Open Access Journals (Sweden)

    Daniela Peukert

    2011-12-01

    Full Text Available Initial axial patterning of the neural tube into forebrain, midbrain, and hindbrain primordia occurs during gastrulation. After this patterning phase, further diversification within the brain is thought to proceed largely independently in the different primordia. However, mechanisms that maintain the demarcation of brain subdivisions at later stages are poorly understood. In the alar plate of the caudal forebrain there are two principal units, the thalamus and the pretectum, each of which is a developmental compartment. Here we show that proper neuronal differentiation of the thalamus requires Lhx2 and Lhx9 function. In Lhx2/Lhx9-deficient zebrafish embryos the differentiation process is blocked and the dorsally adjacent Wnt positive epithalamus expands into the thalamus. This leads to an upregulation of Wnt signaling in the caudal forebrain. Lack of Lhx2/Lhx9 function as well as increased Wnt signaling alter the expression of the thalamus specific cell adhesion factor pcdh10b and lead subsequently to a striking anterior-posterior disorganization of the caudal forebrain. We therefore suggest that after initial neural tube patterning, neurogenesis within a brain compartment influences the integrity of the neuronal progenitor pool and border formation of a neuromeric compartment.

  4. Forebrain overexpression of CaMKII abolishes cingulate long term depression and reduces mechanical allodynia and thermal hyperalgesia

    Directory of Open Access Journals (Sweden)

    Tsien Joe Z

    2006-06-01

    Full Text Available Abstract Activity-dependent synaptic plasticity is known to be important in learning and memory, persistent pain and drug addiction. Glutamate NMDA receptor activation stimulates several protein kinases, which then trigger biochemical cascades that lead to modifications in synaptic efficacy. Genetic and pharmacological techniques have been used to show a role for Ca2+/calmodulin-dependent kinase II (CaMKII in synaptic plasticity and memory formation. However, it is not known if increasing CaMKII activity in forebrain areas affects behavioral responses to tissue injury. Using genetic and pharmacological techniques, we were able to temporally and spatially restrict the over expression of CaMKII in forebrain areas. Here we show that genetic overexpression of CaMKII in the mouse forebrain selectively inhibits tissue injury-induced behavioral sensitization, including allodynia and hyperalgesia, while behavioral responses to acute noxious stimuli remain intact. CaMKII overexpression also inhibited synaptic depression induced by a prolonged repetitive stimulation in the ACC, suggesting an important role for CaMKII in the regulation of cingulate neurons. Our results suggest that neuronal CaMKII activity in the forebrain plays a role in persistent pain.

  5. Long-term effects of cholinergic basal forebrain lesions on neuropeptide Y and somatostatin immunoreactivity in rat neocortex

    NARCIS (Netherlands)

    Gaykema, R.P.A.; Compaan, J.C.; Nyakas, C.; Horvath, E.; Luiten, P.G.M.

    1989-01-01

    The effect of cholinergic basal forebrain lesions on immunoreactivity to somatostatin (SOM-i) and neuropeptide-Y (NPY-i) was investigated in the rat parietal cortex, 16-18 months after multiple bilateral ibotenic acid injections in the nucleus basalis complex. As a result of the lesion, the choliner

  6. Auditory display of knee-joint vibration signals

    Science.gov (United States)

    Krishnan, Sridhar; Rangayyan, Rangaraj M.; Bell, G. Douglas; Frank, Cyril B.

    2001-12-01

    Sounds generated due to rubbing of knee-joint surfaces may lead to a potential tool for noninvasive assessment of articular cartilage degeneration. In the work reported in the present paper, an attempt is made to perform computer-assisted auscultation of knee joints by auditory display (AD) of vibration signals (also known as vibroarthrographic or VAG signals) emitted during active movement of the leg. Two types of AD methods are considered: audification and sonification. In audification, the VAG signals are scaled in time and frequency using a time-frequency distribution to facilitate aural analysis. In sonification, the instantaneous mean frequency and envelope of the VAG signals are derived and used to synthesize sounds that are expected to facilitate more accurate diagnosis than the original signals by improving their aural quality. Auditory classification experiments were performed by two orthopedic surgeons with 37 VAG signals including 19 normal and 18 abnormal cases. Sensitivity values (correct detection of abnormality) of 31%, 44%, and 83%, and overall classification accuracies of 53%, 40%, and 57% were obtained with the direct playback, audification, and sonification methods, respectively. The corresponding d' scores were estimated to be 1.10, -0.36, and 0.55. The high sensitivity of the sonification method indicates that the technique could lead to improved detection of knee-joint abnormalities; however, additional work is required to improve its specificity and achieve better overall performance.

  7. Modifying Directionality through Auditory System Scaling in a Robotic Lizard

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    2010-01-01

    The peripheral auditory system of a lizard is strongly directional. This directionality is created by acoustical coupling of the two eardrums and is strongly dependent on characteristics of the middle ear, such as interaural distance, resonance frequency of the middle ear cavity and of the tympanum....... Therefore, directionality should be strongly influenced by their scaling. In the present study, we have exploited an FPGA–based mobile robot based on a model of the lizard ear to investigate the influence of scaling on the directional response, in terms of the robot’s performance in a phonotaxis task...

  8. Basic Auditory Processing Deficits in Dyslexia: Systematic Review of the Behavioral and Event-Related Potential/Field Evidence

    Science.gov (United States)

    Hämäläinen, Jarmo A.; Salminen, Hanne K.; Leppänen, Paavo H. T.

    2013-01-01

    A review of research that uses behavioral, electroencephalographic, and/or magnetoencephalographic methods to investigate auditory processing deficits in individuals with dyslexia is presented. Findings show that measures of frequency, rise time, and duration discrimination as well as amplitude modulation and frequency modulation detection were…

  9. Behavioral estimates of human frequency selectivity at low frequencies

    DEFF Research Database (Denmark)

    Orellana, Carlos Andrés Jurado

    A fundamental property of our hearing organ is its ability to break down sound into different spectral components, allowing us to make use of the richness in natural sound phenomena. Auditory filters, which conceptualize this property of the ear, however, have not been appropriately described at ...... frequencies or considering larger bandwidths), due to the much narrower absolute bandwidths observed at low frequencies. Besides, observed increases in filter shape variability suggest that individual differences in perception are likely to increase at very low frequencies....... at low sound frequencies. As a consequence of our lack of knowledge, we cannot accurately model our perception of complex low-frequency sound (such as that emitted by wind turbines or industrial processes, which can easily produce annoyance) nor make meaningful predictions of our perception based...... on physical sound measurements. In this PhD thesis a detailed description of frequency selectivity at low frequencies is given. Different experiments have been performed to determine the properties of human auditory filters. Besides, loudness perception of low-frequency sinusoidal signals has been evaluated...

  10. THE EFFECTS OF SALICYLATE ON AUDITORY EVOKED POTENTIAL AMPLITWDE FROM THE AUDITORY CORTEX AND AUDITORY BRAINSTEM

    Institute of Scientific and Technical Information of China (English)

    Brian Sawka; SUN Wei

    2014-01-01

    Tinnitus has often been studied using salicylate in animal models as they are capable of inducing tempo-rary hearing loss and tinnitus. Studies have recently observed enhancement of auditory evoked responses of the auditory cortex (AC) post salicylate treatment which is also shown to be related to tinnitus like behavior in rats. The aim of this study was to observe if enhancements of the AC post salicylate treatment are also present at structures in the brainstem. Four male Sprague Dawley rats with AC implanted electrodes were tested for both AC and auditory brainstem response (ABR) recordings pre and post 250 mg/kg intraperitone-al injections of salicylate. The responses were recorded as the peak to trough amplitudes of P1-N1 (AC), ABR wave V, and ABR waveⅡ. AC responses resulted in statistically significant enhancement of ampli-tude at 2 hours post salicylate with 90 dB stimuli tone bursts of 4, 8, 12, and 20 kHz. Wave V of ABR re-sponses at 90 dB resulted in a statistically significant reduction of amplitude 2 hours post salicylate and a mean decrease of amplitude of 31%for 16 kHz. WaveⅡamplitudes at 2 hours post treatment were signifi-cantly reduced for 4, 12, and 20 kHz stimuli at 90 dB SPL. Our results suggest that the enhancement chang-es of the AC related to salicylate induced tinnitus are generated superior to the level of the inferior colliculus and may originate in the AC.

  11. Influence of oxygen tension on dopaminergic differentiation of human fetal stem cells of midbrain and forebrain origin.

    Science.gov (United States)

    Krabbe, Christina; Bak, Sara Thornby; Jensen, Pia; von Linstow, Christian; Martínez Serrano, Alberto; Hansen, Claus; Meyer, Morten

    2014-01-01

    Neural stem cells (NSCs) constitute a promising source of cells for transplantation in Parkinson's disease (PD), but protocols for controlled dopaminergic differentiation are not yet available. Here we investigated the influence of oxygen on dopaminergic differentiation of human fetal NSCs derived from the midbrain and forebrain. Cells were differentiated for 10 days in vitro at low, physiological (3%) versus high, atmospheric (20%) oxygen tension. Low oxygen resulted in upregulation of vascular endothelial growth factor and increased the proportion of tyrosine hydroxylase-immunoreactive (TH-ir) cells in both types of cultures (midbrain: 9.1 ± 0.5 and 17.1 ± 0.4 (Pcells). Regardless of oxygen levels, the content of TH-ir cells with mature neuronal morphologies was higher for midbrain as compared to forebrain cultures. Proliferative Ki67-ir cells were found in both types of cultures, but the relative proportion of these cells was significantly higher for forebrain NSCs cultured at low, as compared to high, oxygen tension. No such difference was detected for midbrain-derived cells. Western blot analysis revealed that low oxygen enhanced β-tubulin III and GFAP expression in both cultures. Up-regulation of β-tubulin III was most pronounced for midbrain cells, whereas GFAP expression was higher in forebrain as compared to midbrain cells. NSCs from both brain regions displayed less cell death when cultured at low oxygen tension. Following mictrotransplantation into mouse striatal slice cultures predifferentiated midbrain NSCs were found to proliferate and differentiate into substantial numbers of TH-ir neurons with mature neuronal morphologies, particularly at low oxygen. In contrast, predifferentiated forebrain NSCs microtransplanted using identical conditions displayed little proliferation and contained few TH-ir cells, all of which had an immature appearance. Our data may reflect differences in dopaminergic differentiation capacity and region-specific requirements

  12. Hippocampal Sclerosis but Not Normal Aging or Alzheimer Disease Is Associated With TDP-43 Pathology in the Basal Forebrain of Aged Persons.

    Science.gov (United States)

    Cykowski, Matthew D; Takei, Hidehiro; Van Eldik, Linda J; Schmitt, Frederick A; Jicha, Gregory A; Powell, Suzanne Z; Nelson, Peter T

    2016-05-01

    Transactivating responsive sequence (TAR) DNA-binding protein 43-kDa (TDP-43) pathology has been described in various brain diseases, but the full anatomical distribution and clinical and biological implications of that pathology are incompletely characterized. Here, we describe TDP-43 neuropathology in the basal forebrain, hypothalamus, and adjacent nuclei in 98 individuals (mean age, 86 years; median final mini-mental state examination score, 27). On examination blinded to clinical and pathologic diagnoses, we identified TDP-43 pathology that most frequently involved the ventromedial basal forebrain in 19 individuals (19.4%). As expected, many of these brains had comorbid pathologies including those of Alzheimer disease (AD), Lewy body disease (LBD), and/or hippocampal sclerosis of aging (HS-Aging). The basal forebrain TDP-43 pathology was strongly associated with comorbid HS-Aging (odds ratio = 6.8, p = 0.001), whereas there was no significant association between basal forebrain TDP-43 pathology and either AD or LBD neuropathology. In this sample, there were some cases with apparent preclinical TDP-43 pathology in the basal forebrain that may indicate that this is an early affected area in HS-Aging. We conclude that TDP-43 pathology in the basal forebrain is strongly associated with HS-Aging. These results raise questions about a specific pathogenetic relationship between basal forebrain TDP-43 and non-HS-Aging comorbid diseases (AD and LBD).

  13. Relationship between Sympathetic Skin Responses and Auditory Hypersensitivity to Different Auditory Stimuli.

    Science.gov (United States)

    Kato, Fumi; Iwanaga, Ryoichiro; Chono, Mami; Fujihara, Saori; Tokunaga, Akiko; Murata, Jun; Tanaka, Koji; Nakane, Hideyuki; Tanaka, Goro

    2014-07-01

    [Purpose] Auditory hypersensitivity has been widely reported in patients with autism spectrum disorders. However, the neurological background of auditory hypersensitivity is currently not clear. The present study examined the relationship between sympathetic nervous system responses and auditory hypersensitivity induced by different types of auditory stimuli. [Methods] We exposed 20 healthy young adults to six different types of auditory stimuli. The amounts of palmar sweating resulting from the auditory stimuli were compared between groups with (hypersensitive) and without (non-hypersensitive) auditory hypersensitivity. [Results] Although no group × type of stimulus × first stimulus interaction was observed for the extent of reaction, significant type of stimulus × first stimulus interaction was noted for the extent of reaction. For an 80 dB-6,000 Hz stimulus, the trends for palmar sweating differed between the groups. For the first stimulus, the variance became larger in the hypersensitive group than in the non-hypersensitive group. [Conclusion] Subjects who regularly felt excessive reactions to auditory stimuli tended to have excessive sympathetic responses to repeated loud noises compared with subjects who did not feel excessive reactions. People with auditory hypersensitivity may be classified into several subtypes depending on their reaction patterns to auditory stimuli.

  14. GRK5 Deficiency Leads to Selective Basal Forebrain Cholinergic Neuronal Vulnerability.

    Science.gov (United States)

    He, Minchao; Singh, Prabhakar; Cheng, Shaowu; Zhang, Qiang; Peng, Wei; Ding, XueFeng; Li, Longxuan; Liu, Jun; Premont, Richard T; Morgan, Dave; Burns, Jeffery M; Swerdlow, Russell H; Suo, William Z

    2016-05-19

    Why certain diseases primarily affect one specific neuronal subtype rather than another is a puzzle whose solution underlies the development of specific therapies. Selective basal forebrain cholinergic (BFC) neurodegeneration participates in cognitive impairment in Alzheimer's disease (AD), yet the underlying mechanism remains elusive. Here, we report the first recapitulation of the selective BFC neuronal loss that is typical of human AD in a mouse model termed GAP. We created GAP mice by crossing Tg2576 mice that over-express the Swedish mutant human β-amyloid precursor protein gene with G protein-coupled receptor kinase-5 (GRK5) knockout mice. This doubly defective mouse displayed significant BFC neuronal loss at 18 months of age, which was not observed in either of the singly defective parent strains or in the wild type. Along with other supporting evidence, we propose that GRK5 deficiency selectively renders BFC neurons more vulnerable to degeneration.

  15. Whole-Brain Monosynaptic Afferent Inputs to Basal Forebrain Cholinergic System

    Science.gov (United States)

    Hu, Rongfeng; Jin, Sen; He, Xiaobin; Xu, Fuqiang; Hu, Ji

    2016-01-01

    The basal forebrain cholinergic system (BFCS) robustly modulates many important behaviors, such as arousal, attention, learning and memory, through heavy projections to cortex and hippocampus. However, the presynaptic partners governing BFCS activity still remain poorly understood. Here, we utilized a recently developed rabies virus-based cell-type-specific retrograde tracing system to map the whole-brain afferent inputs of the BFCS. We found that the BFCS receives inputs from multiple cortical areas, such as orbital frontal cortex, motor cortex, and insular cortex, and that the BFCS also receives dense inputs from several subcortical nuclei related to motivation and stress, including lateral septum, central amygdala, paraventricular nucleus of hypothalamus, dorsal raphe, and parabrachial nucleus. Interestingly, we found that the BFCS receives inputs from the olfactory areas and the entorhinal–hippocampal system. These results greatly expand our knowledge about the connectivity of the mouse BFCS and provided important preliminary indications for future exploration of circuit function. PMID:27777554

  16. Genetic ablation of Dicer in adult forebrain neurons results in abnormal tau hyperphosphorylation and neurodegeneration

    DEFF Research Database (Denmark)

    Hébert, Sébastien S; Papadopoulou, Aikaterini S; Smith, Pascal

    2010-01-01

    Type III RNase Dicer is responsible for the maturation and function of microRNA (miRNA) molecules in the cell. It is now well-documented that Dicer and the fine-tuning of the miRNA gene network are important for neuronal integrity. However, the underlying mechanisms involved in neuronal death......, particularly in the adult brain, remain poorly defined. Here we show that the absence of Dicer in the adult forebrain is accompanied by a mixed neurodegenerative phenotype. Although neuronal loss is observed in the hippocampus, cellular shrinkage is predominant in the cortex. Interestingly, neuronal...... demonstrate that miRNAs belonging to the miR-15 family are potent regulators of ERK1 expression in mouse neuronal cells and co-expressed with ERK1/2 in vivo. Finally, we show that miR-15a is specifically downregulated in Alzheimer's disease brain. In summary, these results support the hypothesis that changes...

  17. Effects of asymmetry and learning on phonotaxis in a robot based on the lizard auditory system

    DEFF Research Database (Denmark)

    Zhang, L.; Hallam, J.; Christensen-Dalsgaard, J.

    2012-01-01

    Lizards have strong directional hearing across a broad band of frequencies. The directionality can be attributed to the acoustical properties of the ear, especially the strong acoustical coupling of the two eardrums. The peripheral auditory system of the lizard has previously been modeled...... and magnitude of their intrinsic bias. To attain effective directional hearing, the bias in the peripheral system should be compensated. In this article, with the peripheral models, we design a decision model and a behavior model, a virtual robot, to simulate the auditory system of the lizard in software...

  18. Transient forebrain ischemia-induced neuronal degeneration in fascia dentata transplants.

    Science.gov (United States)

    Tønder, N; Aznar, S; Johansen, F F

    1994-01-01

    Fascia dentata tissue blocks from newborn rats were grafted into one-week-old, ibotenic acid-induced lesions of the fascia dentata, or the normal fascia dentata of adult rats. After at least 2 months survival the recipient rats were subjected to 10 min of forebrain ischemia (4-vessel occlusion), and examined 2 or 4 days later for neuronal degeneration in the host hippocampi and the transplants, by silver staining and immunohistochemistry. Transplants survived well in both normal and lesioned host brains, with easily recognizable subfields and layers and presence of normal types of principal and non-principal neurons. As expected, argyrophilic, degenerating neurons were present in the pyramidal cell layer of CAl and CA3c of the non-grafted contralateral host hippocampus and in the contralateral dentate hilus (CA4). In the hilus the degeneration corresponded to the loss of somatostatin-immunoreactive neurons, while parvalbumin-immunoreactive neurons were spared. In the dentate transplants degenerating neurons were observed in the granule cell layer, the hilus and the adjacent CA3 pyramidal cell layer. There was no obvious loss of either somatostatin- or parvalbumin-immunoreactive neurons. The degeneration varied considerably between transplants, from a few to large groups of silver stained neurons, but this difference did not display any obvious relation to grafting into normal or lesioned hosts, the exact location of the grafts or the general organization and distribution of intrinsic or extrinsic host afferents in the grafts. The results demonstrate that both ischemia-susceptible and -resistant types of neurons grafted to normal and lesioned adult rat brains are susceptible to transient forebrain ischemia after transplantation. In spite of an extensive reorganization of transplant nerve connections, the physiologicalbiochemical mechanisms necessary for the induction of ischemic cell death were accordingly present in the transplants.

  19. Temporal profile of neuronal damage in a model of transient forebrain ischemia.

    Science.gov (United States)

    Pulsinelli, W A; Brierley, J B; Plum, F

    1982-05-01

    This study examined the temporal profile of ischemic neuronal damage following transient bilateral forebrain ischemia in the rat model of four-vessel occlusion. Wistar rats were subjected to transient but severe forebrain ischemia by permanently occluding the vertebral arteries and 24 hours later temporarily occluding the common carotid arteries for 10, 20, or 30 minutes. Carotid artery blood flow was restored and the rats were killed by perfusion-fixation after 3, 6, 24, and 72 hours. Rats with postischemic convulsions were discarded. Ischemic neuronal damage was graded in accordance with conventional neuropathological criteria. Ten minutes of four-vessel occlusion produced scattered ischemic cell change in the cerebral hemispheres of most rats. The time to onset of visible neuronal damage varied among brain regions and in some regions progressively worsened with time. After 30 minutes of ischemia, small to medium-sized striatal neurons were damaged early while the initiation of visible damage to hippocampal neurons in the h1 zone was delayed for 3 to 6 hours. The number of damaged neurons in neocortex (layer 3, layers 5 and 6, or both) and hippocampus (h1, h3-5, paramedian zone) increased significantly (p less than 0.01) between 24 and 72 hours. The unique delay in onset of ischemic cell change and the protracted increase in its incidence between 24 and 72 hours could reflect either delayed appearance of ischemic change in previously killed neurons or a delayed insult that continued to jeopardize compromised but otherwise viable neurons during the postischemic period.

  20. Immunohistochemical organization of the forebrain in the white sturgeon, Acipenser transmontanus.

    Science.gov (United States)

    Piñuela, Carmen; Northcutt, R Glenn

    2007-01-01

    The distribution of substance P (SP), leucine-enkephalin (LENK), serotonin (5HT), dopamine (DA), and tyrosine hydroxylase (TH) was examined in the forebrain of the white sturgeon in order to evaluate several anatomical hypotheses based on cytoarchitectonics, and to gain a better understanding of the evolution of the forebrain in ray-finned fishes. The subpallium of the telencephalon has the highest concentration of the neuropeptides SP and LENK, allowing the pallial-subpallial border to be easily distinguished. The distribution of dopamine is similar to that of serotonin in the subpallium, fibers positive for these transmitters are particularly dense in the dorsal and ventral divisions of the subpallium. In addition, a small population of DA- and 5HT-positive cell bodies--which appear to be unique to sturgeons--was identified at the level of the anterior commissure. The internal granular layer of the olfactory bulbs had large numbers of TH-positive cell bodies and fibers, as did the rostral subpallium. The occurrence of cell bodies positive for LENK in the dorsal nucleus of the rostral subpallium supports the hypothesis that this nucleus is homologous to the striatum in other vertebrates. This is further reinforced by the apparent origin of an ascending dopaminergic pathway from cells in the posterior tubercle that are likely homologous to the ventral tegmental area/substantia nigra in land vertebrates. Finally, the differential distribution of SP and TH in the pallium supports the hypothesis that the pallium, or area dorsalis, can be divided medially into a rostral division (Dm), a caudal division (Dp) that is the main pallial target of secondary olfactory projections, and a narrow lateral division (Dd+Dl) immediately adjacent to the attachment of the tela choroidea along the entire rostrocaudal length of the telencephalic hemisphere.

  1. Forebrain-specific ablation of phospholipase Cγ1 causes manic-like behavior.

    Science.gov (United States)

    Yang, Y R; Jung, J H; Kim, S-J; Hamada, K; Suzuki, A; Kim, H J; Lee, J H; Kwon, O-B; Lee, Y K; Kim, J; Kim, E-K; Jang, H-J; Kang, D-S; Choi, J-S; Lee, C J; Marshall, J; Koh, H-Y; Kim, C-J; Seok, H; Kim, S H; Choi, J H; Choi, Y-B; Cocco, L; Ryu, S H; Kim, J-H; Suh, P-G

    2017-01-31

    Manic episodes are one of the major diagnostic symptoms in a spectrum of neuropsychiatric disorders that include schizophrenia, obsessive-compulsive disorder and bipolar disorder (BD). Despite a possible association between BD and the gene encoding phospholipase Cγ1 (PLCG1), its etiological basis remains unclear. Here, we report that mice lacking phospholipase Cγ1 (PLCγ1) in the forebrain (Plcg1(f/f); CaMKII) exhibit hyperactivity, decreased anxiety-like behavior, reduced depressive-related behavior, hyperhedonia, hyperphagia, impaired learning and memory and exaggerated startle responses. Inhibitory transmission in hippocampal pyramidal neurons and striatal dopamine receptor D1-expressing neurons of Plcg1-deficient mice was significantly reduced. The decrease in inhibitory transmission is likely due to a reduced number of γ-aminobutyric acid (GABA)-ergic boutons, which may result from impaired localization and/or stabilization of postsynaptic CaMKII (Ca(2+)/calmodulin-dependent protein kinase II) at inhibitory synapses. Moreover, mutant mice display impaired brain-derived neurotrophic factor-tropomyosin receptor kinase B-dependent synaptic plasticity in the hippocampus, which could account for deficits of spatial memory. Lithium and valproate, the drugs presently used to treat mania associated with BD, rescued the hyperactive phenotypes of Plcg1(f/f); CaMKII mice. These findings provide evidence that PLCγ1 is critical for synaptic function and plasticity and that the loss of PLCγ1 from the forebrain results in manic-like behavior.Molecular Psychiatry advance online publication, 31 January 2017; doi:10.1038/mp.2016.261.

  2. Tonotopic representation of missing fundamental complex sounds in the human auditory cortex.

    Science.gov (United States)

    Fujioka, Takako; Ross, Bernhard; Okamoto, Hidehiko; Takeshima, Yasuyuki; Kakigi, Ryusuke; Pantev, Christo

    2003-07-01

    The N1m component of the auditory evoked magnetic field in response to tones and complex sounds was examined in order to clarify whether the tonotopic representation in the human secondary auditory cortex is based on perceived pitch or the physical frequency spectrum of the sound. The investigated stimulus parameters were the fundamental frequencies (F0 = 250, 500 and 1000 Hz), the spectral composition of the higher harmonics of the missing fundamental sounds (2nd to 5th, 6th to 9th and 10th to 13th harmonic) and the frequencies of pure tones corresponding to F0 and to the lowest component of each complex sound. Tonotopic gradients showed that high frequencies were more medially located than low frequencies for the pure tones and for the centre frequency of the complex tones. Furthermore, in the superior-inferior direction, the tonotopic gradients were different between pure tones and complex sounds. The results were interpreted as reflecting different processing in the auditory cortex for pure tones and complex sounds. This hypothesis was supported by the result of evoked responses to complex sounds having longer latencies. A more pronounced tonotopic representation in the right hemisphere gave evidence for right hemispheric dominance in spectral processing.

  3. The temporal relationship between the brainstem and primary cortical auditory evoked potentials.

    Science.gov (United States)

    Shaw, N A

    1995-10-01

    Many methods are employed in order to define more precisely the generators of an evoked potential (EP) waveform. One technique is to compare the timing of an EP whose origin is well established with that of one whose origin is less certain. In the present article, the latency of the primary cortical auditory evoked potential (PCAEP) was compared to each of the seven subcomponents which compose the brainstem auditory evoked potential (BAEP). The data for this comparison was derived from a retrospective analysis of previous recordings of the PCAEP and BAEP. Central auditory conduction time (CACT) was calculated by subtracting the latency of the cochlear nucleus BAEP component (wave III) from that of the PCAEP. It was found that CACT in humans is 12 msec which is more than double that of central somatosensory conduction time. The interpeak latencies between BAEP waves V, VI, and VII and the PCAEP were also calculated. It was deduced that all three waves must have an origin rather more caudally within the central auditory system than is commonly supposed. In addition, it is demonstrated that the early components of the middle latency AEP (No and Na) largely reside within the time domain between the termination of the BAEP components and the PCAEP which would be consistent with their being far field reflections of midbrain and subcortical auditory activity. It is concluded that as the afferent volley ascends the central auditory pathways, it generates not a sequence of high frequency BAEP responses but rather a succession of slower post-synaptic waves. The only means of reconciling the timing of the BAEP waves with that of the PCAEP is to assume that the generation of all the BAEP components must be largely restricted to a quite confined region within the auditory nerve and the lower half of the pons.

  4. The relationship of phonological ability, speech perception and auditory perception in adults with dyslexia.

    Directory of Open Access Journals (Sweden)

    Jeremy eLaw

    2014-07-01

    Full Text Available This study investigated whether auditory, speech perception and phonological skills are tightly interrelated or independently contributing to reading. We assessed each of these three skills in 36 adults with a past diagnosis of dyslexia and 54 matched normal reading adults. Phonological skills were tested by the typical threefold tasks, i.e. rapid automatic naming, verbal short term memory and phonological awareness. Dynamic auditory processing skills were assessed by means of a frequency modulation (FM and an amplitude rise time (RT; an intensity discrimination task (ID was included as a non-dynamic control task. Speech perception was assessed by means of sentences and words in noise tasks. Group analysis revealed significant group differences in auditory tasks (i.e. RT and ID and in phonological processing measures, yet no differences were found for speech perception. In addition, performance on RT discrimination correlated with reading but this relation was mediated by phonological processing and not by speech in noise. Finally, inspection of the individual scores revealed that the dyslexic readers showed an increased proportion of deviant subjects on the slow-dynamic auditory and phonological tasks, yet each individual dyslexic reader does not display a clear pattern of deficiencies across the levels of processing skills. Although our results support phonological and slow-rate dynamic auditory deficits which relate to literacy, they suggest that at the individual level, problems in reading and writing cannot be explained by the cascading auditory theory. Instead, dyslexic adults seem to vary considerably in the extent to which each of the auditory and phonological factors are expressed and interact with environmental and higher-order cognitive influences.

  5. Assessing the aging effect on auditory-verbal memory by Persian version of dichotic auditory verbal memory test

    Directory of Open Access Journals (Sweden)

    Zahra Shahidipour

    2014-01-01

    Conclusion: Based on the obtained results, significant reduction in auditory memory was seen in aged group and the Persian version of dichotic auditory-verbal memory test, like many other auditory verbal memory tests, showed the aging effects on auditory verbal memory performance.

  6. A comparative study of event-related coupling patterns during an auditory oddball task in schizophrenia

    Science.gov (United States)

    Bachiller, Alejandro; Poza, Jesús; Gómez, Carlos; Molina, Vicente; Suazo, Vanessa; Hornero, Roberto

    2015-02-01

    Objective. The aim of this research is to explore the coupling patterns of brain dynamics during an auditory oddball task in schizophrenia (SCH). Approach. Event-related electroencephalographic (ERP) activity was recorded from 20 SCH patients and 20 healthy controls. The coupling changes between auditory response and pre-stimulus baseline were calculated in conventional EEG frequency bands (theta, alpha, beta-1, beta-2 and gamma), using three coupling measures: coherence, phase-locking value and Euclidean distance. Main results. Our results showed a statistically significant increase from baseline to response in theta coupling and a statistically significant decrease in beta-2 coupling in controls. No statistically significant changes were observed in SCH patients. Significance. Our findings support the aberrant salience hypothesis, since SCH patients failed to change their coupling dynamics between stimulus response and baseline when performing an auditory cognitive task. This result may reflect an impaired communication among neural areas, which may be related to abnormal cognitive functions.

  7. Membrane potential dynamics of populations of cortical neurons during auditory streaming.

    Science.gov (United States)

    Farley, Brandon J; Noreña, Arnaud J

    2015-10-01

    How a mixture of acoustic sources is perceptually organized into discrete auditory objects remains unclear. One current hypothesis postulates that perceptual segregation of different sources is related to the spatiotemporal separation of cortical responses induced by each acoustic source or stream. In the present study, the dynamics of subthreshold membrane potential activity were measured across the entire tonotopic axis of the rodent primary auditory cortex during the auditory streaming paradigm using voltage-sensitive dye imaging. Consistent with the proposed hypothesis, we observed enhanced spatiotemporal segregation of cortical responses to alternating tone sequences as their frequency separation or presentation rate was increased, both manipulations known to promote stream segregation. However, across most streaming paradigm conditions tested, a substantial cortical region maintaining a response to both tones coexisted with more peripheral cortical regions responding more selectively to one of them. We propose that these coexisting subthreshold representation types could provide neural substrates to support the flexible switching between the integrated and segregated streaming percepts.

  8. Optogenetic stimulation of the auditory pathway for research and future prosthetics.

    Science.gov (United States)

    Moser, Tobias

    2015-10-01

    Sound is encoded by spiral ganglion neurons (SGNs) in the hearing organ, the cochlea, with great temporal, spectral and intensity resolution. When hearing fails, electric stimulation by implanted prostheses can partially restore hearing. Optical stimulation promises a fundamental advance of hearing restoration over electric prostheses since light can be conveniently focused and hence might dramatically improve frequency resolution of sound encoding. Combining optogenetic manipulation of neurons with innovative optical stimulation technology promises versatile spatiotemporal stimulation patterns in the auditory system. Therefore, using optical stimulation of SGNs also has great potential for auditory research. Here, I review recent progress in optogenetic stimulation of the auditory system and its potential for future application in research and hearing restoration.

  9. Neuromagnetic fields reveal cortical plasticity when learning an auditory discrimination task.

    Science.gov (United States)

    Cansino, S; Williamson, S J

    1997-08-01

    Auditory evoked neuromagnetic fields of the primary and association auditory cortices were recorded while subjects learned to discriminate small differences in frequency and intensity between two consecutive tones. When discrimination was no better than chance, evoked field patterns across the scalp manifested no significant differences between correct and incorrect responses. However, when performance was correct on at least 75% of the trials, the spatial pattern of magnetic field differed significantly between correct and incorrect responses during the first 70 ms following the onset of the second tone. In this respect, the magnetic field pattern predicted when the subject would make an incorrect judgment more than 100 ms prior to indicating the judgment by a button press. One subject improved discrimination for much smaller differences between stimuli after 200 h of training. Evidence of cortical plasticity with improved discrimination is provided by an accompanying decrease of the relative magnetic field amplitude of the 100 ms response components in the primary and association auditory cortices.

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

    Directory of Open Access Journals (Sweden)

    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

  11. Use of auditory learning to manage listening problems in children

    OpenAIRE

    Moore, David R.; Halliday, Lorna F.; Amitay, Sygal

    2008-01-01

    This paper reviews recent studies that have used adaptive auditory training to address communication problems experienced by some children in their everyday life. It considers the auditory contribution to developmental listening and language problems and the underlying principles of auditory learning that may drive further refinement of auditory learning applications. Following strong claims that language and listening skills in children could be improved by auditory learning, researchers hav...

  12. Neural representation of concurrent harmonic sounds in monkey primary auditory cortex: implications for models of auditory scene analysis.

    Science.gov (United States)

    Fishman, Yonatan I; Steinschneider, Mitchell; Micheyl, Christophe

    2014-09-10

    The ability to attend to a particular sound in a noisy environment is an essential aspect of hearing. To accomplish this feat, the auditory system must segregate sounds that overlap in frequency and time. Many natural sounds, such as human voices, consist of harmonics of a common fundamental frequency (F0). Such harmonic complex tones (HCTs) evoke a pitch corresponding to their F0. A difference in pitch between simultaneous HCTs provides a powerful cue for their segregation. The neural mechanisms underlying concurrent sound segregation based on pitch differences are poorly understood. Here, we examined neural responses in monkey primary auditory cortex (A1) to two concurrent HCTs that differed in F0 such that they are heard as two separate "auditory objects" with distinct pitches. We found that A1 can resolve, via a rate-place code, the lower harmonics of both HCTs, a prerequisite for deriving their pitches and for their perceptual segregation. Onset asynchrony between the HCTs enhanced the neural representation of their harmonics, paralleling their improved perceptual segregation in humans. Pitches of the concurrent HCTs could also be temporally represented by neuronal phase-locking at their respective F0s. Furthermore, a model of A1 responses using harmonic templates could qualitatively reproduce psychophysical data on concurrent sound segregation in humans. Finally, we identified a possible intracortical homolog of the "object-related negativity" recorded noninvasively in humans, which correlates with the perceptual segregation of concurrent sounds. Findings indicate that A1 contains sufficient spectral and temporal information for segregating concurrent sounds based on differences in pitch.

  13. Environmental enrichment improves response strength, threshold, selectivity, and latency of auditory cortex neurons.

    Science.gov (United States)

    Engineer, Navzer D; Percaccio, Cherie R; Pandya, Pritesh K; Moucha, Raluca; Rathbun, Daniel L; Kilgard, Michael P

    2004-07-01

    Over the last 50 yr, environmental enrichment has been shown to generate more than a dozen changes in brain anatomy. The consequences of these physical changes on information processing have not been well studied. In this study, rats were housed in enriched or standard conditions either prior to or after reaching sexual maturity. Evoked potentials from awake rats and extracellular recordings from anesthetized rats were used to document responses of auditory cortex neurons. This report details several significant, new findings about the influence of housing conditions on the responses of rat auditory cortex neurons. First, enrichment dramatically increases the strength of auditory cortex responses. Tone-evoked potentials of enriched rats, for example, were more than twice the amplitude of rats raised in standard laboratory conditions. Second, cortical responses of both young and adult animals benefit from exposure to an enriched environment and are degraded by exposure to an impoverished environment. Third, housing condition resulted in rapid remodeling of cortical responses in <2 wk. Fourth, recordings made under anesthesia indicate that enrichment increases the number of neurons activated by any sound. This finding shows that the evoked potential plasticity documented in awake rats was not due to differences in behavioral state. Finally, enrichment made primary auditory cortex (A1) neurons more sensitive to quiet sounds, more selective for tone frequency, and altered their response latencies. These experiments provide the first evidence of physiologic changes in auditory cortex processing resulting from generalized environmental enrichment.

  14. Auditory cortical delta-entrainment interacts with oscillatory power in multiple fronto-parietal networks.

    Science.gov (United States)

    Keitel, Anne; Ince, Robin A A; Gross, Joachim; Kayser, Christoph

    2017-02-15

    The timing of slow auditory cortical activity aligns to the rhythmic fluctuations in speech. This entrainment is considered to be a marker of the prosodic and syllabic encoding of speech, and has been shown to correlate with intelligibility. Yet, whether and how auditory cortical entrainment is influenced by the activity in other speech-relevant areas remains unknown. Using source-localized MEG data, we quantified the dependency of auditory entrainment on the state of oscillatory activity in fronto-parietal regions. We found that delta band entrainment interacted with the oscillatory activity in three distinct networks. First, entrainment in the left anterior superior temporal gyrus (STG) was modulated by beta power in orbitofrontal areas, possibly reflecting predictive top-down modulations of auditory encoding. Second, entrainment in the left Heschl's Gyrus and anterior STG was dependent on alpha power in central areas, in line with the importance of motor structures for phonological analysis. And third, entrainment in the right posterior STG modulated theta power in parietal areas, consistent with the engagement of semantic memory. These results illustrate the topographical network interactions of auditory delta entrainment and reveal distinct cross-frequency mechanisms by which entrainment can interact with different cognitive processes underlying speech perception.

  15. Response properties of neurons in the cat's putamen during auditory discrimination.

    Science.gov (United States)

    Zhao, Zhenling; Sato, Yu; Qin, Ling

    2015-10-01

    The striatum integrates diverse convergent input and plays a critical role in the goal-directed behaviors. To date, the auditory functions of striatum are less studied. Recently, it was demonstrated that auditory cortico-striatal projections influence behavioral performance during a frequency discrimination task. To reveal the functions of striatal neurons in auditory discrimination, we recorded the single-unit spike activities in the putamen (dorsal striatum) of free-moving cats while performing a Go/No-go task to discriminate the sounds with different modulation rates (12.5 Hz vs. 50 Hz) or envelopes (damped vs. ramped). We found that the putamen neurons can be broadly divided into four groups according to their contributions to sound discrimination. First, 40% of neurons showed vigorous responses synchronized to the sound envelope, and could precisely discriminate different sounds. Second, 18% of neurons showed a high preference of ramped to damped sounds, but no preference for modulation rate. They could only discriminate the change of sound envelope. Third, 27% of neurons rapidly adapted to the sound stimuli, had no ability of sound discrimination. Fourth, 15% of neurons discriminated the sounds dependent on the reward-prediction. Comparing to passively listening condition, the activities of putamen neurons were significantly enhanced by the engagement of the auditory tasks, but not modulated by the cat's behavioral choice. The coexistence of multiple types of neurons suggests that the putamen is involved in the transformation from auditory representation to stimulus-reward association.

  16. Paired associative stimulation of the auditory system: a proof-of-principle study.

    Directory of Open Access Journals (Sweden)

    Martin Schecklmann

    Full Text Available BACKGROUND: Paired associative stimulation (PAS consisting of repeated application of transcranial magnetic stimulation (TMS pulses and contingent exteroceptive stimuli has been shown to induce neuroplastic effects in the motor and somatosensory system. The objective was to investigate whether the auditory system can be modulated by PAS. METHODS: Acoustic stimuli (4 kHz were paired with TMS of the auditory cortex with intervals of either 45 ms (PAS(45 ms or 10 ms (PAS(10 ms. Two-hundred paired stimuli were applied at 0.1 Hz and effects were compared with low frequency repetitive TMS (rTMS at 0.1 Hz (200 stimuli and 1 Hz (1000 stimuli in eleven healthy students. Auditory cortex excitability was measured before and after the interventions by long latency auditory evoked potentials (AEPs for the tone (4 kHz used in the pairing, and a control tone (1 kHz in a within subjects design. RESULTS: Amplitudes of the N1-P2 complex were reduced for the 4 kHz tone after both PAS(45 ms and PAS(10 ms, but not after the 0.1 Hz and 1 Hz rTMS protocols with more pronounced effects for PAS(45 ms. Similar, but less pronounced effects were observed for the 1 kHz control tone. CONCLUSION: These findings indicate that paired associative stimulation may induce tonotopically specific and also tone unspecific human auditory cortex plasticity.

  17. Temporal pattern recognition based on instantaneous spike rate coding in a simple auditory system.

    Science.gov (United States)

    Nabatiyan, A; Poulet, J F A; de Polavieja, G G; Hedwig, B

    2003-10-01

    Auditory pattern recognition by the CNS is a fundamental process in acoustic communication. Because crickets communicate with stereotyped patterns of constant frequency syllables, they are established models to investigate the neuronal mechanisms of auditory pattern recognition. Here we provide evidence that for the neural processing of amplitude-modulated sounds, the instantaneous spike rate rather than the time-averaged neural activity is the appropriate coding principle by comparing both coding parameters in a thoracic interneuron (Omega neuron ON1) of the cricket (Gryllus bimaculatus) auditory system. When stimulated with different temporal sound patterns, the analysis of the instantaneous spike rate demonstrates that the neuron acts as a low-pass filter for syllable patterns. The instantaneous spike rate is low at high syllable rates, but prominent peaks in the instantaneous spike rate are generated as the syllable rate resembles that of the species-specific pattern. The occurrence and repetition rate of these peaks in the neuronal discharge are sufficient to explain temporal filtering in the cricket auditory pathway as they closely match the tuning of phonotactic behavior to different sound patterns. Thus temporal filtering or "pattern recognition" occurs at an early stage in the auditory pathway.

  18. Auditory training during development mitigates a hearing loss-induced perceptual deficit.

    Science.gov (United States)

    Kang, Ramanjot; Sarro, Emma C; Sanes, Dan H

    2014-01-01

    Sensory experience during early development can shape the central nervous system and this is thought to influence adult perceptual skills. In the auditory system, early induction of conductive hearing loss (CHL) leads to deficits in central auditory coding properties in adult animals, and this is accompanied by diminished perceptual thresholds. In contrast, a brief regimen of auditory training during development can enhance the perceptual skills of animals when tested in adulthood. Here, we asked whether a brief period of training during development could compensate for the perceptual deficits displayed by adult animals reared with CHL. Juvenile gerbils with CHL, and age-matched controls, were trained on a frequency modulation (FM) detection task for 4 or 10 days. The performance of each group was subsequently assessed in adulthood, and compared to adults with normal hearing (NH) or adults raised with CHL that did not receive juvenile training. We show that as juveniles, both CHL and NH animals display similar FM detection thresholds that are not immediately impacted by the perceptual training. However, as adults, detection thresholds and psychometric function slopes of these animals were significantly improved. Importantly, CHL adults with juvenile training displayed thresholds that approached NH adults. Additionally, we found that hearing impaired animals trained for 10 days displayed adult thresholds closer to untrained adults than those trained for 4 days. Thus, a relatively brief period of auditory training may compensate for the deleterious impact of hearing deprivation on auditory perception on the trained task.

  19. Positive and negative reinforcement activate human auditory cortex.

    Science.gov (United States)

    Weis, Tina; Puschmann, Sebastian; Brechmann, André; Thiel, Christiane M

    2013-01-01

    Prior studies suggest that reward modulates neural activity in sensory cortices, but less is known about punishment. We used functional magnetic resonance imaging and an auditory discrimination task, where participants had to judge the duration of frequency modulated tones. In one session correct performance resulted in financial gains at the end of the trial, in a second session incorrect performance resulted in financial loss. Incorrect performance in the rewarded as well as correct performance in the punishment condition resulted in a neutral outcome. The size of gains and losses was either low or high (10 or 50 Euro cent) depending on the direction of frequency modulation. We analyzed neural activity at the end of the trial, during reinforcement, and found increased neural activity in auditory cortex when gaining a financial reward as compared to gaining no reward and when avoiding financial loss as compared to receiving a financial loss. This was independent on the size of gains and losses. A similar pattern of neural activity for both gaining a reward and avoiding a loss was also seen in right middle temporal gyrus, bilateral insula and pre-supplemental motor area, here however neural activity was lower after correct responses compared to incorrect responses. To summarize, this study shows that the activation of sensory cortices, as previously shown for gaining a reward is also seen during avoiding a loss.

  20. Positive and negative reinforcement activate human auditory cortex

    Directory of Open Access Journals (Sweden)

    Tina eWeis

    2013-12-01

    Full Text Available Prior studies suggest that reward modulates neural activity in sensory cortices, but less is known about punishment. We used functional magnetic resonance imaging and an auditory discrimination task, where participants had to judge the duration of frequency modulated tones. In one session correct performance resulted in financial gains at the end of the trial, in a second session incorrect performance resulted in financial loss. Incorrect performance in the rewarded as well as correct performance in the punishment condition resulted in a neutral outcome. The size of gains and losses was either low or high (10 or 50 Euro cent depending on the direction of frequency modulation. We analyzed neural activity at the end of the trial, during reinforcement, and found increased neural activity in auditory cortex when gaining a financial reward as compared to gaining no reward and when avoiding financial loss as compared to receiving a financial loss. This was independent on the size of gains and losses. A similar pattern of neural activity for both gaining a reward and avoiding a loss was also seen in right middle temporal gyrus, bilateral insula and pre-supplemental motor area, here however neural activity was lower after correct responses compared to incorrect responses. To summarize, this study shows that the activation of sensory cortices, as previously shown for gaining a reward is also seen during avoiding a loss.

  1. Auditory midbrain representation of a break in interaural correlation.

    Science.gov (United States)

    Wang, Qian; Li, Liang

    2015-10-01

    The auditory peripheral system filters broadband sounds into narrowband waves and decomposes narrowband waves into quickly varying temporal fine structures (TFSs) and slowly varying envelopes. When a noise is presented binaurally (with the interaural correlation being 1), human listeners can detect a transient break in interaural correlation (BIC), which does not alter monaural inputs substantially. The central correlates of BIC are unknown. This study examined whether phase locking-based frequency-following responses (FFRs) of neuron populations in the rat auditory midbrain [inferior colliculus (IC)] to interaurally correlated steady-state narrowband noises are modulated by introduction of a BIC. The results showed that the noise-induced FFR exhibited both a TFS component (FFRTFS) and an envelope component (FFREnv), signaling the center frequency and bandwidth, respectively. Introduction of either a BIC or an interaurally correlated amplitude gap (which had the summated amplitude matched to the BIC) significantly reduced both FFRTFS and FFREnv. However, the BIC-induced FFRTFS reduction and FFREnv reduction were not correlated with the amplitude gap-induced FFRTFS reduction and FFREnv reduction, respectively. Thus, although introduction of a BIC does not affect monaural inputs, it causes a temporary reduction in sustained responses of IC neuron populations to the noise. This BIC-induced FFR reduction is not based on a simple linear summation of noise signals.

  2. Improving Hearing Performance Using Natural Auditory Coding Strategies

    Science.gov (United States)

    Rattay, Frank

    Sound transfer from the human ear to the brain is based on three quite different neural coding principles when the continuous temporal auditory source signal is sent as binary code in excellent quality via 30,000 nerve fibers per ear. Cochlear implants are well-accepted neural prostheses for people with sensory hearing loss, but currently the devices are inspired only by the tonotopic principle. According to this principle, every sound frequency is mapped to a specific place along the cochlea. By electrical stimulation, the frequency content of the acoustic signal is distributed via few contacts of the prosthesis to corresponding places and generates spikes there. In contrast to the natural situation, the artificially evoked information content in the auditory nerve is quite poor, especially because the richness of the temporal fine structure of the neural pattern is replaced by a firing pattern that is strongly synchronized with an artificial cycle duration. Improvement in hearing performance is expected by involving more of the ingenious strategies developed during evolution.

  3. Neural entrainment to rhythmically-presented auditory, visual and audio-visual speech in children

    Directory of Open Access Journals (Sweden)

    Alan James Power

    2012-07-01

    Full Text Available Auditory cortical oscillations have been proposed to play an important role in speech perception. It is suggested that the brain may take temporal ‘samples’ of information from the speech stream at different rates, phase-resetting ongoing oscillations so that they are aligned with similar frequency bands in the input (‘phase locking’. Information from these frequency bands is then bound together for speech perception. To date, there are no explorations of neural phase-locking and entrainment to speech input in children. However, it is clear from studies of language acquisition that infants use both visual speech information and auditory speech information in learning. In order to study neural entrainment to speech in typically-developing children, we use a rhythmic entrainment paradigm (underlying 2 Hz or delta rate based on repetition of the syllable ba, presented in either the auditory modality alone, the visual modality alone, or as auditory-visual speech (via a talking head. To ensure attention to the task, children aged 13 years were asked to press a button as fast as possible when the ba stimulus violated the rhythm for each stream type. Rhythmic violation depended on delaying the occurrence of a ba in the isochronous stream. Neural entrainment was demonstrated for all stream types, and individual differences in standardized measures of language processing were related to auditory entrainment at the theta rate. Further, there was significant modulation of the preferred phase of auditory entrainment in the theta band when visual speech cues were present, indicating cross-modal phase resetting. The rhythmic entrainment paradigm developed here offers a method for exploring individual differences in oscillatory phase locking during development. In particular, a method for assessing neural entrainment and cross-modal phase resetting would be useful for exploring developmental learning difficulties thought to involve temporal sampling

  4. Auditory-visual spatial interaction and modularity

    Science.gov (United States)

    Radeau, M

    1994-02-01

    The results of dealing with the conditions for pairing visual and auditory data coming from spatially separate locations argue for cognitive impenetrability and computational autonomy, the pairing rules being the Gestalt principles of common fate and proximity. Other data provide evidence for pairing with several properties of modular functioning. Arguments for domain specificity are inferred from comparison with audio-visual speech. Suggestion of innate specification can be found in developmental data indicating that the grouping of visual and auditory signals is supported very early in life by the same principles that operate in adults. Support for a specific neural architecture comes from neurophysiological studies of the bimodal (auditory-visual) neurons of the cat superior colliculus. Auditory-visual pairing thus seems to present the four main properties of the Fodorian module.

  5. [Approaches to therapy of auditory agnosia].

    Science.gov (United States)

    Fechtelpeter, A; Göddenhenrich, S; Huber, W; Springer, L

    1990-01-01

    In a 41-year-old stroke patient with bitemporal brain damage, we found severe signs of auditory agnosia 6 months after onset. Recognition of environmental sounds was extremely impaired when tested in a multiple choice sound-picture matching task, whereas auditory discrimination between sounds and picture identifications by written names was almost undisturbed. In a therapy experiment, we tried to enhance sound recognition via semantic categorization and association, imitation of sound and analysis of auditory features, respectively. The stimulation of conscious auditory analysis proved to be increasingly effective over a 4-week period of therapy. We were able to show that the patient's improvement was not only a simple effect of practicing, but it was stable and carried over to nontrained items.

  6. Environment for Auditory Research Facility (EAR)

    Data.gov (United States)

    Federal Laboratory Consortium — EAR is an auditory perception and communication research center enabling state-of-the-art simulation of various indoor and outdoor acoustic environments. The heart...

  7. Effect of omega-3 on auditory system

    Directory of Open Access Journals (Sweden)

    Vida Rahimi

    2014-01-01

    Full Text Available Background and Aim: Omega-3 fatty acid have structural and biological roles in the body 's various systems . Numerous studies have tried to research about it. Auditory system is affected a s well. The aim of this article was to review the researches about the effect of omega-3 on auditory system.Methods: We searched Medline , Google Scholar, PubMed, Cochrane Library and SID search engines with the "auditory" and "omega-3" keywords and read textbooks about this subject between 19 70 and 20 13.Conclusion: Both excess and deficient amounts of dietary omega-3 fatty acid can cause harmful effects on fetal and infant growth and development of brain and central nervous system esspesially auditory system. It is important to determine the adequate dosage of omega-3.

  8. A lateralized functional auditory network is involved in anuran sexual selection

    Indian Academy of Sciences (India)

    FEI XUE; GUANGZHAN FANG; XIZI YUE; ERMI ZHAO; STEVEN E BRAUTH; YEZHONG TANG

    2016-12-01

    Right ear advantage (REA) exists in many land vertebrates in which the right ear and left hemisphere preferentiallyprocess conspecific acoustic stimuli such as those related to sexual selection. Although ecological and neural mechanismsfor sexual selection have been widely studied, the brain networks involved are still poorly understood. In this study weused multi-channel electroencephalographic data in combination with Granger causal connectivity analysis to demonstrate,for the first time, that auditory neural network interconnecting the left and right midbrain and forebrain functionasymmetrically in the Emei music frog (Babina daunchina), an anuran species which exhibits REA. The results showedthe network was lateralized. Ascending connections between the mesencephalon and telencephalon were stronger in theleft side while descending ones were stronger in the right, which matched with the REA in this species and implied thatinhibition from the forebrainmay induce REA partly. Connections from the telencephalon to ipsilateral mesencephalon inresponse to white noise were the highest in the non-reproductive stage while those to advertisement calls were the highestin reproductive stage, implying the attention resources and living strategy shift when entered the reproductive season.Finally, these connection changes were sexually dimorphic, revealing sex differences in reproductive roles.

  9. Angiotensin type 1a receptors in the forebrain subfornical organ facilitate leptin-induced weight loss through brown adipose tissue thermogenesis

    Directory of Open Access Journals (Sweden)

    Colin N. Young

    2015-04-01

    Conclusions: These data identify a novel interaction between angiotensin-II and leptin in the control of BAT thermogenesis and body weight, and highlight a previously unrecognized role for the forebrain SFO in metabolic regulation.

  10. The possible influence of noise frequency components on the health of exposed industrial workers - A review

    Directory of Open Access Journals (Sweden)

    K V Mahendra Prashanth

    2011-01-01

    Full Text Available Noise is a common occupational health hazard in most industrial settings. An assessment of noise and its adverse health effects based on noise intensity is inadequate. For an efficient evaluation of noise effects, frequency spectrum analysis should also be included. This paper aims to substantiate the importance of studying the contribution of noise frequencies in evaluating health effects and their association with physiological behavior within human body. Additionally, a review of studies published between 1988 and 2009 that investigate the impact of industrial/occupational noise on auditory and non-auditory effects and the probable association and contribution of noise frequency components to these effects is presented. The relevant studies in English were identified in Medknow, Medline, Wiley, Elsevier, and Springer publications. Data were extracted from the studies that fulfilled the following criteria: title and/or abstract of the given study that involved industrial/occupational noise exposure in relation to auditory and non-auditory effects or health effects. Significant data on the study characteristics, including noise frequency characteristics, for assessment were considered in the study. It is demonstrated that only a few studies have considered the frequency contributions in their investigations to study auditory effects and not non-auditory effects. The data suggest that significant adverse health effects due to industrial noise include auditory and heart-related problems. The study provides a strong evidence for the claims that noise with a major frequency characteristic of around 4 kHz has auditory effects and being deficient in data fails to show any influence of noise frequency components on non-auditory effects. Furthermore, specific noise levels and frequencies predicting the corresponding health impacts have not yet been validated. There is a need for advance research to clarify the importance of the dominant noise frequency

  11. Can comodulation masking release occur when frequency changes could promote perceptual segregation of the on-frequency and flanking bands?

    DEFF Research Database (Denmark)

    Verhey, Jesko L; Epp, Bastian; Stasiak, Arkadiusz

    2013-01-01

    bands relative to the inhibitory areas (as seen in physiological recordings using stationary flanking bands). Preliminary physiological results in the cochlear nucleus of the Guinea pig show that a correlate of CMR can also be found at this level of the auditory pathway with sweeping flanking bands.......A common characteristic of natural sounds is that the level fluctuations in different frequency regions are coherent. The ability of the auditory system to use this comodulation is shown when a sinusoidal signal is masked by a masker centred at the signal frequency (on-frequency masker, OFM...... and comodulation could serve as cues to indicate which of the stimulus components originate from one source. If the common fate of frequency components is the stronger binding cue, the sweeping FBs and the OFM with a fixed centre frequency should no longer form one auditory object and the CMR should be abolished...

  12. Speech enhancement for listeners with hearing loss based on a model for vowel coding in the auditory midbrain.

    Science.gov (United States)

    Rao, Akshay; Carney, Laurel H

    2014-07-01

    A novel signal-processing strategy is proposed to enhance speech for listeners with hearing loss. The strategy focuses on improving vowel perception based on a recent hypothesis for vowel coding in the auditory system. Traditionally, studies of neural vowel encoding have focused on the representation of formants (peaks in vowel spectra) in the discharge patterns of the population of auditory-nerve (AN) fibers. A recent hypothesis focuses instead on vowel encoding in the auditory midbrain, and suggests a robust representation of formants. AN fiber discharge rates are characterized by pitch-related fluctuations having frequency-dependent modulation depths. Fibers tuned to frequencies near formants exhibit weaker pitch-related fluctuations than those tuned to frequencies between formants. Many auditory midbrain neurons show tuning to amplitude modulation frequency in addition to audio frequency. According to the auditory midbrain vowel encoding hypothesis, the response map of a population of midbrain neurons tuned to modulations near voice pitch exhibits minima near formant frequencies, due to the lack of strong pitch-related fluctuations at their inputs. This representation is robust over the range of noise conditions in which speech intelligibility is also robust for normal-hearing listeners. Based on this hypothesis, a vowel-enhancement strategy has been proposed that aims to restore vowel encoding at the level of the auditory midbrain. The signal processing consists of pitch tracking, formant tracking, and formant enhancement. The novel formant-tracking method proposed here estimates the first two formant frequencies by modeling characteristics of the auditory periphery, such as saturated discharge rates of AN fibers and modulation tuning properties of auditory midbrain neurons. The formant enhancement stage aims to restore the representation of formants at the level of the midbrain by increasing the dominance of a single harmonic near each formant and saturating

  13. A critical period for auditory thalamocortical connectivity

    DEFF Research Database (Denmark)

    Rinaldi Barkat, Tania; Polley, Daniel B; Hensch, Takao K

    2011-01-01

    connectivity by in vivo recordings and day-by-day voltage-sensitive dye imaging in an acute brain slice preparation. Passive tone-rearing modified response strength and topography in mouse primary auditory cortex (A1) during a brief, 3-d window, but did not alter tonotopic maps in the thalamus. Gene...... locus of change for the tonotopic plasticity. The evolving postnatal connectivity between thalamus and cortex in the days following hearing onset may therefore determine a critical period for auditory processing....

  14. The integration of song environment by catecholaminergic systems innervating the auditory telencephalon of adult female European starlings.

    Science.gov (United States)

    Sockman, Keith W; Salvante, Katrina G

    2008-04-01

    Mate choice is among the most consequential decisions a sexually reproducing organism can make. In many songbird species, females make mate-choice decisions based, in part, on variation between males in songs that reflect their quality. Importantly, females may adjust their choice relative to the prevalence of high quality songs. In European starlings (Sturnus vulgaris), females prefer males that primarily sing long songs over those that primarily sing short songs, and sensitivity of the auditory telencephalon to song length depends on the prevalence of long songs in the environment. Several lines of evidence suggest a role for noradrenergic innervation of the auditory telencephalon in mediating this neuro- and behavioral plasticity. To simulate variation in quality of the song environment, we exposed adult female starlings to 1 week of either long or short songs and then quantified several monoamines and their metabolites in the caudomedial mesopallium and caudomedial nidopallium (NCM) using high performance liquid chromatography. We also used immunocytochemistry to assess these areas for immunoreactive dopamine-beta-hydroxylase (DBH-ir), the enzyme that synthesizes norepinephrine. We found that long songs elevated levels of the principal norepinephrine metabolite, the principal dopamine metabolite, and the probability of DBH-ir in the NCM compared to short songs. Song environment did not appear to influence norepinephrine or dopamine levels. Thus, the quality of the song environment regulates the local secretion of catecholamines, particularly norepinephrine, in the female auditory telencephalon. This may form a basis for plasticity in forebrain sensitivity and mate-choice behavior based on the prevalence of high-quality males.

  15. Auditory-motor mapping for pitch control in singers and nonsingers.

    Science.gov (United States)

    Jones, Jeffery A; Keough, Dwayne

    2008-09-01

    Little is known about the basic processes underlying the behavior of singing. This experiment was designed to examine differences in the representation of the mapping between fundamental frequency (F0) feedback and the vocal production system in singers and nonsingers. Auditory feedback regarding F0 was shifted down in frequency while participants sang the consonant-vowel /ta/. During the initial frequency-altered trials, singers compensated to a lesser degree than nonsingers, but this difference was reduced with continued exposure to frequency-altered feedback. After brief exposure to frequency altered auditory feedback, both singers and nonsingers suddenly heard their F0 unaltered. When participants received this unaltered feedback, only singers' F0 values were found to be significantly higher than their F0 values produced during baseline and control trials. These aftereffects in singers were replicated when participants sang a different note than the note they produced while hearing altered feedback. Together, these results suggest that singers rely more on internal models than nonsingers to regulate vocal productions rather than real time auditory feedback.

  16. 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.

  17. Auditory model inversion and its application

    Institute of Scientific and Technical Information of China (English)

    ZHAO Heming; WANG Yongqi; CHEN Xueqin

    2005-01-01

    Auditory model has been applied to several aspects of speech signal processing field, and appears to be effective in performance. This paper presents the inverse transform of each stage of one widely used auditory model. First of all it is necessary to invert correlogram and reconstruct phase information by repetitious iterations in order to get auditory-nerve firing rate. The next step is to obtain the negative parts of the signal via the reverse process of the HWR (Half Wave Rectification). Finally the functions of inner hair cell/synapse model and Gammatone filters have to be inverted. Thus the whole auditory model inversion has been achieved. An application of noisy speech enhancement based on auditory model inversion algorithm is proposed. Many experiments show that this method is effective in reducing noise.Especially when SNR of noisy speech is low it is more effective than other methods. Thus this auditory model inversion method given in this paper is applicable to speech enhancement field.

  18. Auditory dysfunction associated with solvent exposure

    Directory of Open Access Journals (Sweden)

    Fuente Adrian

    2013-01-01

    Full Text Available Abstract Background A number of studies have demonstrated that solvents may induce auditory dysfunction. However, there is still little knowledge regarding the main signs and symptoms of solvent-induced hearing loss (SIHL. The aim of this research was to investigate the association between solvent exposure and adverse effects on peripheral and central auditory functioning with a comprehensive audiological test battery. Methods Seventy-two solvent-exposed workers and 72 non-exposed workers were selected to participate in the study. The test battery comprised pure-tone audiometry (PTA, transient evoked otoacoustic emissions (TEOAE, Random Gap Detection (RGD and Hearing-in-Noise test (HINT. Results Solvent-exposed subjects presented with poorer mean test results than non-exposed subjects. A bivariate and multivariate linear regression model analysis was performed. One model for each auditory outcome (PTA, TEOAE, RGD and HINT was independently constructed. For all of the models solvent exposure was significantly associated with the auditory outcome. Age also appeared significantly associated with some auditory outcomes. Conclusions This study provides further evidence of the possible adverse effect of solvents on the peripheral and central auditory functioning. A discussion of these effects and the utility of selected hearing tests to assess SIHL is addressed.

  19. 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.

  20. Loss of forebrain MTCH2 decreases mitochondria motility and calcium handling and impairs hippocampal-dependent cognitive functions

    Science.gov (United States)

    Ruggiero, Antonella; Aloni, Etay; Korkotian, Eduard; Zaltsman, Yehudit; Oni-Biton, Efrat; Kuperman, Yael; Tsoory, Michael; Shachnai, Liat; Levin-Zaidman, Smadar; Brenner, Ori; Segal, Menahem; Gross, Atan

    2017-01-01

    Mitochondrial Carrier Homolog 2 (MTCH2) is a novel regulator of mitochondria metabolism, which was recently associated with Alzheimer’s disease. Here we demonstrate that deletion of forebrain MTCH2 increases mitochondria and whole-body energy metabolism, increases locomotor activity, but impairs motor coordination and balance. Importantly, mice deficient in forebrain MTCH2 display a deficit in hippocampus-dependent cognitive functions, including spatial memory, long term potentiation (LTP) and rates of spontaneous excitatory synaptic currents. Moreover, MTCH2-deficient hippocampal neurons display a deficit in mitochondria motility and calcium handling. Thus, MTCH2 is a critical player in neuronal cell biology, controlling mitochondria metabolism, motility and calcium buffering to regulate hippocampal-dependent cognitive functions. PMID:28276496

  1. Influence of interferon-gamma on the differentiation of cholinergic neurons in rat embryonic basal forebrain and septal nuclei

    Institute of Scientific and Technical Information of China (English)

    Yanhong Luo; Lin An

    2006-01-01

    BACKGROUND: Interferon-gamma (IFN-γ) can make neurons in basal forebrain and septal nuclei differentiate into cholinergic neurons by treating the cells in cerebral cortex of newborn rats, without the inhibition from IFN-γ antibody. The important effect of IFN-γ on the development and differentiation of neurons has been found by some scholars.OBJ ECTIVE:To investigate whether IFN-γ has differentiational effect on cholinergic neurons in basal forebrain and septal nuclei, and make clear that the increased number of cholinergic neurons is resulted by cell differentiation or cell proliferation.DESIGN: Controlled observation trial.SETTING: Department of Cell Biology, Medical School, Beijing University.MATERIALS: Sixty-eight female Wistar rats at embryonic 16 days, weighing 250 to 350 g, were enrolled in this study, and they were provided by the Experimental Animal Center, Medical School, Beijing University.IFN-γ was the product of Gibco Company.METHODS: This study was carried out in the Department of Cell Biology, Medical School, Beijing University and Daheng Image Company of Chinese Academy of Sciences during September 1995 to December 2002.The female Wistar rats at embryonic 16 days were sacrificed, and their fetuses were taken out. Primary culture of the isolated basal forebrain and septal nuclei was performed. The cultured nerve cells were assigned into 3 groups: control group (nothing added), IFN-γ group(1×105 U/L interferon), IFN-γ+ IFN-γ antibody group (1 ×105 U/L IFN-γ± IFN-γ antibody). The specific marker enzyme (choline acetyl transferase) of cholinergic neuron was stained with immunohistochemical method. Choline acetyl transferase positive cells were counted, and 14C-acetyl CoA was used as substrate to detect the activity of choline acetyl transferase, so as to reflect the differentiational effect of IFN-γ on cholinergic neuron in basal forebrain and septal nuclei. Flow cytometry was used to analyze cell circle and detect the proliferation of

  2. Music-induced cortical plasticity and lateral inhibition in the human auditory cortex as foundations for tonal tinnitus treatment

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    Christo ePantev

    2012-06-01

    Full Text Available Over the past 15 years, we have studied plasticity in the human auditory cortex by means of magnetoencephalography (MEG. Two main topics nurtured our curiosity: the effects of musical training on plasticity in the auditory system, and the effects of lateral inhibition. One of our plasticity studies found that listening to notched music for three hours inhibited the neuronal activity in the auditory cortex that corresponded to the center-frequency of the notch, suggesting suppression of neural activity by lateral inhibition. Crucially, the overall effects of lateral inhibition on human auditory cortical activity were stronger than the habituation effects. Based on these results we developed a novel treatment strategy for tonal tinnitus - tailor-made notched music training (TMNMT. By notching the music energy spectrum around the individual tinnitus frequency, we intended to attract lateral inhibition to auditory neurons involved in tinnitus perception. So far, the training strategy has been evaluated in two studies. The results of the initial long-term controlled study (12 months supported the validity of the treatment concept: subjective tinnitus loudness and annoyance were significantly reduced after TMNMT but not when notching spared the tinnitus frequencies. Correspondingly, tinnitus-related auditory evoked fields (AEFs were significantly reduced after training. The subsequent short-term (5 days training study indicated that training was more effective in the case of tinnitus frequencies ≤ 8 kHz compared to tinnitus frequencies > 8 kHz, and that training should be employed over a long-term in order to induce more persistent effects. Further development and evaluation of TMNMT therapy are planned. A goal is to transfer this novel, completely non-invasive, and low-cost treatment approach for tonal tinnitus into routine clinical practice.

  3. Asymmetric transfer of auditory perceptual learning

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    Sygal eAmitay

    2012-11-01

    Full Text Available Perceptual skills can improve dramatically even with minimal practice. A major and practical benefit of learning, however, is in transferring the improvement on the trained task to untrained tasks or stimuli, yet the mechanisms underlying this process are still poorly understood. Reduction of internal noise has been proposed as a mechanism of perceptual learning, and while we have evidence that frequency discrimination (FD learning is due to a reduction of internal noise, the source of that noise was not determined. In this study, we examined whether reducing the noise associated with neural phase locking to tones can explain the observed improvement in behavioural thresholds. We compared FD training between two tone durations (15 and 100 ms that straddled the temporal integration window of auditory nerve fibers upon which computational modeling of phase locking noise was based. Training on short tones resulted in improved FD on probe tests of both the long and short tones. Training on long tones resulted in improvement only on the long tones. Simulations of FD learning, based on the computational model and on signal detection theory, were compared with the behavioral FD data. We found that improved fidelity of phase locking accurately predicted transfer of learning from short to long tones, but also predicted transfer from long to short tones. The observed lack of transfer from long to short tones suggests the involvement of a second mechanism. Training may have increased the temporal integration window which could not transfer because integration time for the short tone is limited by its duration. Current learning models assume complex relationships between neural populations that represent the trained stimuli. In contrast, we propose that training-induced enhancement of the signal-to-noise ratio offers a parsimonious explanation of learning and transfer that easily accounts for asymmetric transfer of learning.

  4. Rabbit forebrain cholinergic system: morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus.

    Science.gov (United States)

    Varga, Csaba; Härtig, Wolfgang; Grosche, Jens; Keijser, Jan; Luiten, Paul G M; Seeger, Johannes; Brauer, Kurt; Harkany, Tibor

    2003-06-09

    Although the rabbit brain, in particular the basal forebrain cholinergic system, has become a common model for neuropathological changes associated with Alzheimer's disease, detailed neuroanatomical studies on the morphological organization of basal forebrain cholinergic nuclei and on their output pathways are still awaited. Therefore, we performed quantitative choline acetyltransferase (ChAT) immunocytochemistry to localize major cholinergic nuclei and to determine the number of respective cholinergic neurons in the rabbit forebrain. The density of ChAT-immunoreactive terminals in layer V of distinct neocortical territories and in hippocampal subfields was also measured. Another cholinergic marker, the low-affinity neurotrophin receptor (p75(NTR)), was also employed to identify subsets of cholinergic neurons. Double-immunofluorescence labeling of ChAT and p75(NTR), calbindin D-28k (CB), parvalbumin, calretinin, neuronal nitric oxide synthase (nNOS), tyrosine hydroxylase, or substance P was used to elucidate the neuroanatomical borders of cholinergic nuclei and to analyze the neurochemical complexity of cholinergic cell populations. Cholinergic projection neurons with heterogeneous densities were found in the medial septum, vertical and horizontal diagonal bands of Broca, ventral pallidum, and magnocellular nucleus basalis (MBN)/substantia innominata (SI) complex; cholinergic interneurons were observed in the caudate nucleus, putamen, accumbens nucleus, and olfactory tubercule, whereas the globus pallidus was devoid of cholinergic nerve cells. Cholinergic interneurons were frequently present in the hippocampus and to a lesser extent in cerebral cortex. Cholinergic projection neurons, except those localized in SI, abundantly expressed p75(NTR), and a subset of cholinergic neurons in posterior MBN was immunoreactive for CB and nNOS. A strict laminar distribution pattern of cholinergic terminals was recorded both in the cerebral cortex and in CA1-CA3 and dentate gyrus

  5. Forebrain patterns of c-Fos and FosB induction during cancer-associated anorexia-cachexia in rat.

    Science.gov (United States)

    Konsman, Jan Pieter; Blomqvist, Anders

    2005-05-01

    Forebrain structures are necessary for the initiation of food intake and its coupling to energy expenditure. The cancer-related anorexia-cachexia syndrome is typified by a prolonged increase in metabolic rate resulting in body weight loss which, paradoxically, is accompanied by reduced food intake. The aim of the present work was to study the forebrain expression of Fos proteins as activation markers and thus to identify potential neurobiological mechanisms favouring catabolic processes or modulating food intake in rats suffering from cancer-related anorexia-cachexia. Neurons in forebrain structures showing most pronounced induction of Fos proteins were further identified neurochemically. To provoke anorexia-cachexia, cultured Morris hepatoma 7777 cells were injected subcutaneously in Buffalo rats. This resulted in a slowly growing tumour inducing approximately 7% body weight loss and a 20% reduction in food intake when the tumour represented 1-2% of body mass. Anorexia-cachexia in these animals was found to be accompanied by Fos induction in several hypothalamic nuclei including the paraventricular and ventromedial hypothalamus, in the parastrial nucleus, the amygdala, the bed nucleus of the stria terminalis, ventral striatal structures and the piriform and somatosensory cortices. Neurochemical identification revealed that the vast majority of FosB-positive neurons in the nucleus accumbens, ventral caudate-putamen and other ventral striatal structures contained prodynorphin or proenkephalin mRNA. These findings indicate that forebrain structures that are part of neuronal networks modulating catabolic pathways and food ingestion are activated during tumour-associated anorexia-cachexia and may contribute to the lack of compensatory eating in response to weight loss characterizing this syndrome.

  6. Vulnerability of mossy fiber targets in the rat hippocampus to forebrain ischemia.

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    Hsu, M; Buzsáki, G

    1993-09-01

    Much of the work on forebrain ischemia in the hippocampus has focused on the phenomenon of delayed neuronal death in CA1. It is established that dentate granule cells and CA3 pyramidal cells are resistant to ischemia. However, much less is known about interneuronal involvement in CA3 or ischemic injury in the dentate hilus other than the fact that somatostatin neurons in the latter lose their immunoreactivity. We combined two sensitive methods--heat-shock protein (HSP72) immunocytochemistry and a newly developed Gallyas silver stain for demonstrating impaired cytoskeletal elements--to investigate the extent of ischemic damage to CA3 and the dentate hilus using the four-vessel-occlusion model for inducing forebrain ischemia. HSP72-like immunoreactivity was induced in neuronal populations previously shown to be vulnerable to ischemia. In addition, a distinct subset of interneurons in CA3 was also extremely sensitive to ischemia, even more so than the CA1 pyramidal cells. These neurons are located in the stratum lucidum of CA3 and possess a very high density of dendritic spines. In silver preparations, they were among the first to be impregnated as "dark" neurons, before CA1 pyramidal cells; microglial reaction was also initiated first in the stratum lucidum of CA3. Whereas CA1 damage was most prominent in the septal half of the hippocampus, hilar and CA3 interneuronal damage had a more extensive dorsoventral distribution. Our results also show a far greater extent of damage in hilar neurons than previously reported. At least four hilar cell types were consistently compromised: mossy cells, spiny fusiform cells, sparsely spiny fusiform cells, and long-spined multipolar cells. A common denominator of the injured neurons in CA3 and the hilus was the presence of spines on their dendrites, which in large part accounted for the far greater number of mossy fiber terminals they receive than their non-spiny neighbors. We suggest that the differential vulnerability of neuronal

  7. Electrophysiological changes of CA1 pyramidal neurons following transient forebrain ischemia: an in vivo intracellular recording and staining study.

    Science.gov (United States)

    Xu, Z C; Pulsinelli, W A

    1996-09-01

    1. Electrophysiological changes of CA1 pyramidal neurons in rat hippocampus were studied before, during 5 min forebrain ischemia, and after reperfusion using in vivo intracellular recording and staining techniques. 2. membrane input resistance of CA1 neurons decreased from 25.98 +/- 7.24 M omega (mean +/- SD, n = 42) before ischemia to 16.33 +/- 6.50 M omega shortly after the onset of ischemia (n = 6, P < 0.01). The input resistance fell to zero during ischemic depolarization and quickly returned to 24.42 +/- 10.36 M omega (n = 11) within 2 h after reperfusion. 3. The time constant of CA1 neurons decreased from 11.49 +/- 5.45 ms (n = 36) to 3.09 +/- 1.66 ms (n = 6, P < 0.01) during ischemia. The time constant remained significantly less than preischemic levels within 2 h after reperfusion (5.40 +/- 2.60 ms, n = 13, P < 0.01) and gradually returned to preischemic levels 4-5 h after reperfusion. 4. The spike height decreased from 91 +/- 10.35 mV (n = 45) before ischemia to 82 +/- 8.00 mV (n = 9, P < 0.05) within 2 h after reperfusion and fully returned to preischemic level 2-5 h after reperfusion. The spike width increased from 1.14 +/- 0.22 ms (n = 45) before ischemia to 1.36 +/- 0.22 ms (n = 9, P < 0.05) within 2 h after reperfusion and remained at this level 4-5 h after reperfusion. 5. The spike threshold significantly increased from -54 +/- 3.93 mV (n = 45) before ischemia to -49 +/- 5.04 mV (n = 8, P < 0.01) within 2 h after reperfusion. The rheobase increased accordingly from 0.34 +/- 0.16 nA (n = 41) to 0.73 +/- 0.26 nA (n = 6, P < 0.01). The spike threshold returned to control levels 4-5 h after reperfusion, while the rheobase was still significantly higher than control levels (0.50 +/- 0.21 nA, n = 16, P < 0.01). 6. The frequency of repetitive firing evoked by depolarizing current pulses was suppressed within 2 h after reperfusion (n = 6, P < 0.01). The spike frequency increased slightly 2-5 h after reperfusion but was still significantly below the control

  8. Vocal responses to perturbations in voice auditory feedback in individuals with Parkinson's disease.

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    Hanjun Liu

    Full Text Available BACKGROUND: One of the most common symptoms of speech deficits in individuals with Parkinson's disease (PD is significantly reduced vocal loudness and pitch range. The present study investigated whether abnormal vocalizations in individuals with PD are related to sensory processing of voice auditory feedback. Perturbations in loudness or pitch of voice auditory feedback are known to elicit short latency, compensatory responses in voice amplitude or fundamental frequency. METHODOLOGY/PRINCIPAL FINDINGS: Twelve individuals with Parkinson's disease and 13 age- and sex-matched healthy control subjects sustained a vowel sound (/α/ and received unexpected, brief (200 ms perturbations in voice loudness (±3 or 6 dB or pitch (±100 cents auditory feedback. Results showed that, while all subjects produced compensatory responses in their voice amplitude or fundamental frequency, individuals with PD exhibited larger response magnitudes than the control subjects. Furthermore, for loudness-shifted feedback, upward stimuli resulted in shorter response latencies than downward stimuli in the control subjects but not in individuals with PD. CONCLUSIONS/SIGNIFICANCE: The larger response magnitudes in individuals with PD compared with the control subjects suggest that processing of voice auditory feedback is abnormal in PD. Although the precise mechanisms of the voice feedback processing are unknown, results of this study suggest that abnormal voice control in individuals with PD may be related to dysfunctional mechanisms of error detection or correction in sensory feedback processing.

  9. The influence of visuospatial attention on unattended auditory 40 Hz responses.

    Science.gov (United States)

    Roth, Cullen; Gupta, Cota Navin; Plis, Sergey M; Damaraju, Eswar; Khullar, Siddharth; Calhoun, Vince D; Bridwell, David A

    2013-01-01

    Information must integrate from multiple brain areas in healthy cognition and perception. The present study examined the extent to which cortical responses within one sensory modality are modulated by a complex task conducted within another sensory modality. Electroencephalographic (EEG) responses were measured to a 40 Hz auditory stimulus while individuals attended to modulations in the amplitude of the 40 Hz stimulus, and as a function of the difficulty of the popular computer game Tetris. The steady-state response to the 40 Hz stimulus was isolated by Fourier analysis of the EEG. The response at the stimulus frequency was normalized by the response within the surrounding frequencies, generating the signal-to-noise ratio (SNR). Seven out of eight individuals demonstrate a monotonic increase in the log SNR of the 40 Hz responses going from the difficult visuospatial task to the easy visuospatial task to attending to the auditory stimuli. This pattern is represented statistically by a One-Way ANOVA, indicating significant differences in log SNR across the three tasks. The sensitivity of 40 Hz auditory responses to the visuospatial load was further demonstrated by a significant correlation between log SNR and the difficulty (i.e., speed) of the Tetris task. Thus, the results demonstrate that 40 Hz auditory cortical responses are influenced by an individual's goal-directed attention to the stimulus, and by the degree of difficulty of a complex visuospatial task.

  10. Perceptual grouping over time within and across auditory and tactile modalities.

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    I-Fan Lin

    Full Text Available In auditory scene analysis, population separation and temporal coherence have been proposed to explain how auditory features are grouped together and streamed over time. The present study investigated whether these two theories can be applied to tactile streaming and whether temporal coherence theory can be applied to crossmodal streaming. The results show that synchrony detection between two tones/taps at different frequencies/locations became difficult when one of the tones/taps was embedded in a perceptual stream. While the taps applied to the same location were streamed over time, the taps applied to different locations were not. This observation suggests that tactile stream formation can be explained by population-separation theory. On the other hand, temporally coherent auditory stimuli at different frequencies were streamed over time, but temporally coherent tactile stimuli applied to different locations were not. When there was within-modality streaming, temporally coherent auditory stimuli and tactile stimuli were not streamed over time, either. This observation suggests the limitation of temporal coherence theory when it is applied to perceptual grouping over time.

  11. Slit-Robo signals regulate pioneer axon pathfinding of the tract of the postoptic commissure in the mammalian forebrain.

    Science.gov (United States)

    Ricaño-Cornejo, Itzel; Altick, Amy L; García-Peña, Claudia M; Nural, Hikmet Feyza; Echevarría, Diego; Miquelajáuregui, Amaya; Mastick, Grant S; Varela-Echavarría, Alfredo

    2011-10-01

    During early vertebrate forebrain development, pioneer axons establish a symmetrical scaffold descending longitudinally through the rostral forebrain, thus forming the tract of the postoptic commissure (TPOC). In mouse embryos, this tract begins to appear at embryonic day 9.5 (E9.5) as a bundle of axons tightly constrained at a specific dorsoventral level. We have characterized the participation of the Slit chemorepellants and their Robo receptors in the control of TPOC axon projection. In E9.5-E11.5 mouse embryos, Robo1 and Robo2 are expressed in the nucleus origin of the TPOC (nTPOC), and Slit expression domains flank the TPOC trajectory. These findings suggested that these proteins are important factors in the dorsoventral positioning of the TPOC axons. Consistently with this role, Slit2 inhibited TPOC axon growth in collagen gel cultures, and interfering with Robo function in cultured embryos induced projection errors in TPOC axons. Moreover, absence of both Slit1 and Slit2 or Robo1 and Robo2 in mutant mouse embryos revealed aberrant TPOC trajectories, resulting in abnormal spreading of the tract and misprojections into both ventral and dorsal tissues. These results reveal that Slit-Robo signaling regulates the dorsoventral position of this pioneer tract in the developing forebrain.

  12. Chlordiazepoxide-induced released responding in extinction and punishment-conflict procedures is not altered by neonatal forebrain norepinephrine depletion.

    Science.gov (United States)

    Bialik, R J; Pappas, B A; Pusztay, W

    1982-02-01

    The effects of chlordiazepoxide (CDZ) in extinction and punishment-conflict tasks were examined in rats after neonatal systemic administration of 6-hydroxydopamine (6-OHDA) to deplete forebrain norepinephrine (NE). At about 70 days of age the rats were water deprived and trained for three days to drink in a novel apparatus. On the fourth day (test day) drinking was either extinguished by elimination of water from the drinking tube or punished by lick-contingent shock. Just prior to this test session half of the vehicle and half of the 6-OHDA treated rats were given an injection of CDZ (8 mg/kg IP). Both the injection of CDZ and forebrain NE depletion prolonged responding during extinction and reduced the suppressant effects of punishment in male rats, and these effects were of similar magnitude. Furthermore, CDZ was as effective in neonatal 6-OHDA treated male rats as in vehicle treated rats indicating that decreased transmission is ascending NE fibers caused by CDZ is not solely responsible for its behavioral effects in extinction and conflict tasks. Rather, these effects may involve cooperative mediation by both noradrenergic and serotonergic forebrain terminals. Unexpectedly, CDZ's anti-extinction effect was absent in female rats and its anti-conflict effect observed only in NE depleted females.

  13. Astaxanthin limits fish oil-related oxidative insult in the anterior forebrain of Wistar rats: putative anxiolytic effects?

    Science.gov (United States)

    Mattei, Rita; Polotow, Tatiana G; Vardaris, Cristina V; Guerra, Beatriz A; Leite, José Roberto; Otton, Rosemari; Barros, Marcelo P

    2011-09-01

    The habitual consumption of marine fish is largely associated to human mental health. Fish oil is particularly rich in n-3 polyunsaturated fatty acids that are known to play a role in several neuronal and cognitive functions. In parallel, the orange-pinkish carotenoid astaxanthin (ASTA) is found in salmon and displays important antioxidant and anti-inflammatory properties. Many neuronal dysfunctions and anomalous psychotic behavior (such as anxiety, depression, etc.) have been strongly related to the higher sensitivity of cathecolaminergic brain regions to oxidative stress. Thus, the aim of this work was to study the combined effect of ASTA and fish oil on the redox status in plasma and in the monoaminergic-rich anterior forebrain region of Wistar rats with possible correlations with the anxiolytic behavior. Upon fish oil supplementation, the downregulation of superoxide dismutase and catalase activities combined to increased "free" iron content resulted in higher levels of lipid and protein oxidation in the anterior forebrain of animals. Such harmful oxidative modifications were hindered by concomitant supplementation with ASTA despite ASTA-related antioxidant protection was mainly observed in plasma. Although it is clear that ASTA properly crosses the brain-blood barrier, our data also address a possible indirect role of ASTA in restoring basal oxidative conditions in anterior forebrain of animals: by improving GSH-based antioxidant capacity of plasma. Preliminary anxiolytic tests performed in the elevated plus maze are in alignment with our biochemical observations.

  14. Auditory stimuli mimicking ambient sounds drive temporal "delta-brushes" in premature infants.

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    Mathilde Chipaux

    Full Text Available In the premature infant, somatosensory and visual stimuli trigger an immature electroencephalographic (EEG pattern, "delta-brushes," in the corresponding sensory cortical areas. Whether auditory stimuli evoke delta-brushes in the premature auditory cortex has not been reported. Here, responses to auditory stimuli were studied in 46 premature infants without neurologic risk aged 31 to 38 postmenstrual weeks (PMW during routine EEG recording. Stimuli consisted of either low-volume technogenic "clicks" near the background noise level of the neonatal care unit, or a human voice at conversational sound level. Stimuli were administrated pseudo-randomly during quiet and active sleep. In another protocol, the cortical response to a composite stimulus ("click" and voice was manually triggered during EEG hypoactive periods of quiet sleep. Cortical responses were analyzed by event detection, power frequency analysis and stimulus locked averaging. Before 34 PMW, both voice and "click" stimuli evoked cortical responses with similar frequency-power topographic characteristics, namely a temporal negative slow-wave and rapid oscillations similar to spontaneous delta-brushes. Responses to composite stimuli also showed a maximal frequency-power increase in temporal areas before 35 PMW. From 34 PMW the topography of responses in quiet sleep was different for "click" and voice stimuli: responses to "clicks" became diffuse but responses to voice remained limited to temporal areas. After the age of 35 PMW auditory evoked delta-brushes progressively disappeared and were replaced by a low amplitude response in the same location. Our data show that auditory stimuli mimicking ambient sounds efficiently evoke delta-brushes in temporal areas in the premature infant before 35 PMW. Along with findings in other sensory modalities (visual and somatosensory, these findings suggest that sensory driven delta-brushes represent a ubiquitous feature of the human sensory cortex

  15. Auditory Streaming as an Online Classification Process with Evidence Accumulation.

    Science.gov (United States)

    Barniv, Dana; Nelken, Israel

    2015-01-01

    When human subjects hear a sequence of two alternating pure tones, they often perceive it in one of two ways: as one integrated sequence (a single "stream" consisting of the two tones), or as two segregated sequences, one sequence of low tones perceived separately from another sequence of high tones (two "streams"). Perception of this stimulus is thus bistable. Moreover, subjects report on-going switching between the two percepts: unless the frequency separation is large, initial perception tends to be of integration, followed by toggling between integration and segregation phases. The process of stream formation is loosely named "auditory streaming". Auditory streaming is believed to be a manifestation of human ability to analyze an auditory scene, i.e. to attribute portions of the incoming sound sequence to distinct sound generating entities. Previous studies suggested that the durations of the successive integration and segregation phases are statistically independent. This independence plays an important role in current models of bistability. Contrary to this, we show here, by analyzing a large set of data, that subsequent phase durations are positively correlated. To account together for bistability and positive correlation between subsequent durations, we suggest that streaming is a consequence of an evidence accumulation process. Evidence for segregation is accumulated during the integration phase and vice versa; a switch to the opposite percept occurs stochastically based on this evidence. During a long phase, a large amount of evidence for the opposite percept is accumulated, resulting in a long subsequent phase. In contrast, a short phase is followed by another short phase. We implement these concepts using a probabilistic model that shows both bistability and correlations similar to those observed experimentally.

  16. Automatic teleaudiometry: a low cost method to auditory screening

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    Campelo, Victor Eulálio Sousa

    2010-03-01

    Full Text Available Introduction: The auditory screening' benefits has been demonstrated, however these programs has been restricted to the big centers. Objectives: (a Developing a auditory screening method to distance; (b Testing its accuracy and comparing to the screening audiometry test (AV. Method: The teleaudiometry (TA, consists in a developed software, installed in a computer with phone TDH39. It was realized a study in series in 73 individuals between 17 and 50 years, being 57,%% of the female sex, they were randomly selected between patients and companions of the Hospital das Clínicas. Before were subjected to a symptom questionnaire and otoscopy, the individuals realized the tests of TA AV, with scanning in 20dB in the frequencies of 1,2 and 4kHz following the ASHA (1997 protocol and to the gold standard test of audiometry of pure tones in soundproof booth in aleatory order. Results: the TA has lasted average 125+11s and the AV 65+18s. 69 individuals (94,5% declaring to be found difficult or very easy to performing the TA and 61 (83,6% have considered easy or very easy the AV. The accuracy results of TA and AV were respectively: sensibility (86,7% / 86,7%, specificity (75,9%/ 72,4% and negative predictive value (95,7% / 95,5%, positive predictive value (48,1% / 55,2%. Conclusion: The teleaudiometry has showed a good option as an auditory screening method, presenting accuracy next to screening audiometry. In comparison with this method, the teleaudiometry has presented a similar sensibility, major specificity, negative predictive value and endurance time and, under positive predictive value.

  17. Auditory Streaming as an Online Classification Process with Evidence Accumulation

    Science.gov (United States)

    Barniv, Dana; Nelken, Israel

    2015-01-01

    When human subjects hear a sequence of two alternating pure tones, they often perceive it in one of two ways: as one integrated sequence (a single "stream" consisting of the two tones), or as two segregated sequences, one sequence of low tones perceived separately from another sequence of high tones (two "streams"). Perception of this stimulus is thus bistable. Moreover, subjects report on-going switching between the two percepts: unless the frequency separation is large, initial perception tends to be of integration, followed by toggling between integration and segregation phases. The process of stream formation is loosely named “auditory streaming”. Auditory streaming is believed to be a manifestation of human ability to analyze an auditory scene, i.e. to attribute portions of the incoming sound sequence to distinct sound generating entities. Previous studies suggested that the durations of the successive integration and segregation phases are statistically independent. This independence plays an important role in current models of bistability. Contrary to this, we show here, by analyzing a large set of data, that subsequent phase durations are positively correlated. To account together for bistability and positive correlation between subsequent durations, we suggest that streaming is a consequence of an evidence accumulation process. Evidence for segregation is accumulated during the integration phase and vice versa; a switch to the opposite percept occurs stochastically based on this evidence. During a long phase, a large amount of evidence for the opposite percept is accumulated, resulting in a long subsequent phase. In contrast, a short phase is followed by another short phase. We implement these concepts using a probabilistic model that shows both bistability and correlations similar to those observed experimentally. PMID:26671774

  18. Conditions of auditory health at work: inquiry of the auditoy effect in workers exposed to the occupationl noise

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    Lopes, Andréa Cintra

    2009-03-01

    Full Text Available Introduction: Physiologically, the individuals exposed to the noise may develop a very common pathology; the occupational noise induced hearing loss. Objective: Research the by means of a cross-sectional study, prevalence of occupational hearing loss in workers exposed to noise pressure levels over 85 dB NPL. Method: 400 records of workers exposed to noise pressure levels above 85 db NPS, working in companies of different segments. Results: In this sample, statistically significant differences were observed between the low and high frequencies thresholds and that the work duration influenced in the worsening of high frequencies thresholds bilaterally. As for the laterality no significant differences were confirmed between the ears, as well as the absence of correlation between tinnitus and hearing loss. Conclusion: An intensive work of auditory health promotion and/or auditory loss prevention must be emphasized, especially for workers exposed to high level occupational noises, as well as the appropriate features of individual auditory protection equipment.

  19. An Auditory-Masking-Threshold-Based Noise Suppression Algorithm GMMSE-AMT[ERB] for Listeners with Sensorineural Hearing Loss

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    Hansen John HL

    2005-01-01

    Full Text Available This study describes a new noise suppression scheme for hearing aid applications based on the auditory masking threshold (AMT in conjunction with a modified generalized minimum mean square error estimator (GMMSE for individual subjects with hearing loss. The representation of cochlear frequency resolution is achieved in terms of auditory filter equivalent rectangular bandwidths (ERBs. Estimation of AMT and spreading functions for masking are implemented in two ways: with normal auditory thresholds and normal auditory filter bandwidths (GMMSE-AMT[ERB]-NH and with elevated thresholds and broader auditory filters characteristic of cochlear hearing loss (GMMSE-AMT[ERB]-HI. Evaluation is performed using speech corpora with objective quality measures (segmental SNR, Itakura-Saito, along with formal listener evaluations of speech quality rating and intelligibility. While no measurable changes in intelligibility occurred, evaluations showed quality improvement with both algorithm implementations. However, the customized formulation based on individual hearing losses was similar in performance to the formulation based on the normal auditory system.

  20. Interaction of basal forebrain cholinergic neurons with the glucocorticoid system in stress regulation and cognitive impairment

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    Saswati ePaul

    2015-04-01

    Full Text Available A substantial number of studies on basal forebrain cholinergic neurons (BFCN have provided compelling evidence for their role in the etiology of stress, cognitive aging, Alzheimer’s disease (AD, and other neurodegenerative diseases. BFCN project to a broad range of cortical sites and limbic structures, including the hippocampus, and are involved in stress and cognition. In particular, the hippocampus, the primary target tissue of the glucocorticoid stress hormones, is associated with cognitive function in tandem with hypothalamic-pituitary-adrenal (HPA axis modulation. The present review summarizes glucocorticoid and HPA axis research to date in an effort to establish the manner in which stress affects the release of acetylcholine, glucocorticoids, and their receptor in the context of cognitive processes. We attempt to provide the molecular interactive link between the glucocorticoids and cholinergic system that contributes to BFCN degeneration in stress-induced acceleration of cognitive decline in aging and AD. We also discuss the importance of animal models in facilitating such studies for pharmacological use, which could help decipher disease states and propose leads for pharmacological intervention.

  1. Large-Scale Network Organisation in the Avian Forebrain: A Connectivity Matrix and Theoretical Analysis

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    Murray eShanahan

    2013-07-01

    Full Text Available Many species of birds, including pigeons, possess demonstrable cognitive capacities, and some are capable of cognitive feats matching those of apes. Since mammalian cortex is laminar while the avian telencephalon is nucleated, it is natural to ask whether the brains of these two cognitively capable taxa, despite their apparent anatomical dissimilarities, might exhibit common principles of organisation on some level. Complementing recent investigations of macro-scale brain connectivity in mammals, including humans and macaques, we here present the first large-scale wiring diagram for the forebrain of a bird. Using graph theory, we show that the pigeon telencephalon is organised along similar lines to that of a mammal. Both are modular, small-world networks with a connective core of hub nodes that includes prefrontal-like and hippocampal structures. These hub nodes are, topologically speaking, the most central regions of the pigeon's brain, as well as being the most richly connected, implying a crucial role in information flow. Overall, our analysis suggests that indeed, despite the absence of cortical layers and close to 300 million years of separate evolution, the connectivity of the avian brain conforms to the same organisational principles as the mammalian brain.

  2. NKCC1 controls GABAergic signaling and neuroblast migration in the postnatal forebrain

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    Murray Kerren

    2011-02-01

    Full Text Available Abstract From an early postnatal period and throughout life there is a continuous production of olfactory bulb (OB interneurons originating from neuronal precursors in the subventricular zone. To reach the OB circuits, immature neuroblasts migrate along the rostral migratory stream (RMS. In the present study, we employed cultured postnatal mouse forebrain slices and used lentiviral vectors to label neuronal precursors with GFP and to manipulate the expression levels of the Na-K-2Cl cotransporter NKCC1. We investigated the role of this Cl- transporter in different stages of postnatal neurogenesis, including neuroblast migration and integration in the OB networks once they have reached the granule cell layer (GCL. We report that NKCC1 activity is necessary for maintaining normal migratory speed. Both pharmacological and genetic manipulations revealed that NKCC1 maintains high [Cl-]i and regulates the resting membrane potential of migratory neuroblasts whilst its functional expression is strongly reduced at the time cells reach the GCL. As in other developing systems, NKCC1 shapes GABAA-dependent signaling in the RMS neuroblasts. Also, we show that NKCC1 controls the migration of neuroblasts in the RMS. The present study indeed indicates that the latter effect results from a novel action of NKCC1 on the resting membrane potential, which is independent of GABAA-dependent signaling. All in all, our findings show that early stages of the postnatal recruitment of OB interneurons rely on precise, orchestrated mechanisms that depend on multiple actions of NKCC1.

  3. Forebrain Ischemia Triggers GABAergic System Degeneration in Substantia Nigra at Chronic Stages in Rats

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    B. Lin

    2010-01-01

    Full Text Available The long-term consequences of forebrain ischemia include delayed Parkinson's syndrome. This study revealed delayed neurodegeneration in the substantia nigra 8 weeks after 12.5 minutes of global ischemia in rat brain. Following neuronal loss of 30–40% in central and dorsolateral striatum at day 3, neuronal damage in the substantia nigra (SN was assessed at 4–8 weeks using immunohistochemistry for glutamate decarboxylase 67 (GAD67, vesicular GABA transporter (VGAT, and calretinin (CR. At day 56, the optical density of GAD67-, but not VGAT-, immunoreactivity in substantia nigra pars reticulata (SNR—significantly decreased. CR-neurons concentrated in substantia nigra pars compacta (SNC were reduced by 27% from day 3 (n=5 to day 56 (n=7, ANOVA, p<.01. Movement coordination was impaired at day 56, as evaluated using beam-walking test (time-to-traverse 5.6±1.2 sec versus 11.8±5.4 sec; sham versus ischemia, p<.05, n=5, and 7, resp.. Our results demonstrate delayed impairment of the GABAergic system components in SN and associated with movement deficits after global ischemia.

  4. Birds have primate-like numbers of neurons in the forebrain

    Science.gov (United States)

    Olkowicz, Seweryn; Kocourek, Martin; Lučan, Radek K.; Porteš, Michal; Fitch, W. Tecumseh; Herculano-Houzel, Suzana; Němec, Pavel

    2016-01-01

    Some birds achieve primate-like levels of cognition, even though their brains tend to be much smaller in absolute size. This poses a fundamental problem in comparative and computational neuroscience, because small brains are expected to have a lower information-processing capacity. Using the isotropic fractionator to determine numbers of neurons in specific brain regions, here we show that the brains of parrots and songbirds contain on average twice as many neurons as primate brains of the same mass, indicating that avian brains have higher neuron packing densities than mammalian brains. Additionally, corvids and parrots have much higher proportions of brain neurons located in the pallial telencephalon compared with primates or other mammals and birds. Thus, large-brained parrots and corvids have forebrain neuron counts equal to or greater than primates with much larger brains. We suggest that the large numbers of neurons concentrated in high densities in the telencephalon substantially contribute to the neural basis of avian intelligence. PMID:27298365

  5. The amygdala and basal forebrain as a pathway for motivationally guided attention.

    Science.gov (United States)

    Peck, Christopher J; Salzman, C Daniel

    2014-10-08

    Visual stimuli associated with rewards attract spatial attention. Neurophysiological mechanisms that mediate this process must register both the motivational significance and location of visual stimuli. Recent neurophysiological evidence indicates that the amygdala encodes information about both of these parameters. Furthermore, the firing rate of amygdala neurons predicts the allocation of spatial attention. One neural pathway through which the amygdala might influence attention involves the intimate and bidirectional connections between the amygdala and basal forebrain (BF), a brain area long implicated in attention. Neurons in the rhesus monkey amygdala and BF were therefore recorded simultaneously while subjects performed a detection task in which the stimulus-reward associations of visual stimuli modulated spatial attention. Neurons in BF were spatially selective for reward-predictive stimuli, much like the amygdala. The onset of reward-predictive signals in each brain area suggested different routes of processing for reward-predictive stimuli appearing in the ipsilateral and contralateral fields. Moreover, neurons in the amygdala, but not BF, tracked trial-to-trial fluctuations in spatial attention. These results suggest that the amygdala and BF could play distinct yet inter-related roles in influencing attention elicited by reward-predictive stimuli.

  6. Basal forebrain motivational salience signal enhances cortical processing and decision speed

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    Sylvina M Raver

    2015-10-01

    Full Text Available The basal forebrain (BF contains major projections to the cerebral cortex, and plays a well-documented role in arousal, attention, decision-making, and in modulating cortical activity. BF neuronal degeneration is an early event in Alzheimer’s disease and dementias, and occurs in normal cognitive aging. While the BF is best known for its population of cortically projecting cholinergic neurons, the region is anatomically and neurochemically diverse, and also contains prominent populations of non-cholinergic projection neurons. In recent years, increasing attention has been dedicated to these non-cholinergic BF neurons in order to better understand how non-cholinergic BF circuits control cortical processing and behavioral performance. In this review, we focus on a unique population of putative non-cholinergic BF neurons that encodes the motivational salience of stimuli with a robust ensemble bursting response. We review recent studies that describe the specific physiological and functional characteristics of these BF salience-encoding neurons in behaving animals. These studies support the unifying hypothesis whereby BF salience-encoding neurons act as a gain modulation mechanism of the decision-making process to enhance cortical processing of behaviorally relevant stimuli, and thereby facilitate faster and more precise behavioral responses. This function of BF salience-encoding neurons represents a critical component in determining which incoming stimuli warrant an animal’s attention, and is therefore a fundamental and early requirement of behavioral flexibility.

  7. Excitatory Hindbrain-Forebrain Communication Is Required for Cisplatin-Induced Anorexia and Weight Loss.

    Science.gov (United States)

    Alhadeff, Amber L; Holland, Ruby A; Zheng, Huiyuan; Rinaman, Linda; Grill, Harvey J; De Jonghe, Bart C

    2017-01-11

    Cisplatin chemotherapy is commonly used to treat cancer despite severe energy balance side effects. In rats, cisplatin activates nucleus tractus solitarius (NTS) projections to the lateral parabrachial nucleus (lPBN) and calcitonin-gene related peptide (CGRP) projections from the lPBN to the central nucleus of the amygdala (CeA). We demonstrated previously that CeA glutamate receptor signaling mediates cisplatin-induced anorexia and body weight loss. Here, we used neuroanatomical tracing, immunofluorescence, and confocal imaging to demonstrate that virtually all NTS→lPBN and lPBN→CeA CGRP projections coexpress vesicular glutamate transporter 2 (VGLUT2), providing evidence that excitatory projections mediate cisplatin-induced energy balance dysregulation. To test whether lPBN→CeA projection neurons are required for cisplatin-induced anorexia and weight loss, we inhibited these neurons chemogenetically using a retrograde Cre-recombinase-expressing canine adenovirus-2 in combination with Cre-dependent inhibitory Designer Receptors Exclusive Activated by Designer Drugs (DREADDs) before cisplatin treatment. Inhibition of lPBN→CeA neurons attenuated cisplatin-induced anorexia and body weight loss significantly. Using a similar approach, we additionally demonstrated that inhibition of NTS→lPBN neurons attenuated cisplatin-induced anorexia and body weight loss significantly. Together, our data support the view that excitatory hindbrain-forebrain projections are necessary for cisplatin's untoward effects on energy intake, elucidating a key neuroanatomical circuit driving pathological anorexia and weight loss that accompanies chemotherapy treatment.

  8. Brainstem stimulation increases functional connectivity of basal forebrain-paralimbic network in isoflurane-anesthetized rats.

    Science.gov (United States)

    Pillay, Siveshigan; Liu, Xiping; Baracskay, Péter; Hudetz, Anthony G

    2014-09-01

    Brain states and cognitive-behavioral functions are precisely controlled by subcortical neuromodulatory networks. Manipulating key components of the ascending arousal system (AAS), via deep-brain stimulation, may help facilitate global arousal in anesthetized animals. Here we test the hypothesis that electrical stimulation of the oral part of the pontine reticular nucleus (PnO) under light isoflurane anesthesia, associated with loss of consciousness, leads to cortical desynchronization and specific changes in blood-oxygenation-level-dependent (BOLD) functional connectivity (FC) of the brain. BOLD signals were acquired simultaneously with frontal epidural electroencephalogram before and after PnO stimulation. Whole-brain FC was mapped using correlation analysis with seeds in major centers of the AAS. PnO stimulation produced cortical desynchronization, a decrease in δ- and θ-band power, and an increase in approximate entropy. Significant increases in FC after PnO stimulation occurred between the left nucleus Basalis of Meynert (NBM) as seed and numerous regions of the paralimbic network. Smaller increases in FC were present between the central medial thalamic nucleus and retrosplenium seeds and the left caudate putamen and NBM. The results suggest that, during light anesthesia, PnO stimulation preferentially modulates basal forebrain-paralimbic networks. We speculate that this may be a reflection of disconnected awareness.

  9. Transcriptional Networks Controlled by NKX2-1 in the Development of Forebrain GABAergic Neurons.

    Science.gov (United States)

    Sandberg, Magnus; Flandin, Pierre; Silberberg, Shanni; Su-Feher, Linda; Price, James D; Hu, Jia Sheng; Kim, Carol; Visel, Axel; Nord, Alex S; Rubenstein, John L R

    2016-09-21

    The embryonic basal ganglia generates multiple projection neurons and interneuron subtypes from distinct progenitor domains. Combinatorial interactions of transcription factors and chromatin are thought to regulate gene expression. In the medial ganglionic eminence, the NKX2-1 transcription factor controls regional identity and, with LHX6, is necessary to specify pallidal projection neurons and forebrain interneurons. Here, we dissected the molecular functions of NKX2-1 by defining its chromosomal binding, regulation of gene expression, and epigenetic state. NKX2-1 binding at distal regulatory elements led to a repressed epigenetic state and transcriptional repression in the ventricular zone. Conversely, NKX2-1 is required to establish a permissive chromatin state and transcriptional activation in the sub-ventricular and mantle zones. Moreover, combinatorial binding of NKX2-1 and LHX6 promotes transcriptionally permissive chromatin and activates genes expressed in cortical migrating interneurons. Our integrated approach provides a foundation for elucidating transcriptional networks guiding the development of the MGE and its descendants.

  10. Longitudinal measures of cholinergic forebrain atrophy in the transition from healthy aging to Alzheimer's disease.

    Science.gov (United States)

    Grothe, Michel; Heinsen, Helmut; Teipel, Stefan

    2013-04-01

    Recent evidence from cross-sectional in vivo imaging studies suggests that atrophy of the cholinergic basal forebrain (BF) in Alzheimer's disease (AD) can be distinguished from normal age-related degeneration even at predementia stages of the disease. Longitudinal study designs are needed to specify the dynamics of BF degeneration in the transition from normal aging to AD. We applied recently developed techniques for in vivo volumetry of the BF to serial magnetic resonance imaging scans of 82 initially healthy elderly individuals (60-93 years) and 50 patients with very mild AD (Clinical Dementia Rating score = 0.5) that were clinically followed over an average of 3 ± 1.5 years. BF atrophy rates were found to be significantly higher than rates of global brain shrinkage even in cognitively stable healthy elderly individuals. Compared with healthy control subjects, very mild AD patients showed reduced BF volumes at baseline and increased volume loss over time. Atrophy of the BF was more pronounced in progressive patients compared with those that remained stable. The cholinergic BF undergoes disproportionate degeneration in the aging process, which is further increased by the presence of AD.

  11. Reference and working memory of rats following hippocampal damage induced by transient forebrain ischemia.

    Science.gov (United States)

    Davis, H P; Tribuna, J; Pulsinelli, W A; Volpe, B T

    1986-01-01

    Acquisition of reference and working memory was evaluated in an animal model of cerebral ischemia. Rats were subjected to 30 minutes of transient forebrain ischemia, allowed to recover, and then tested for 95 trials on an 8-arm maze with 5 arms baited. During the 95 trials post ischemic (PI) rats made significantly more working and reference errors than controls (p less than 0.05). However, an analysis of the last 20 trials (75-95) showed that while PI rats and control rats had comparable reference memory (p greater than 0.8). PI rats tended to have a persistent working memory deficit compared to controls (p less than 0.06). Subsequent morphologic analysis showed that PI rats had almost complete loss of pyramidal neurons in the anterior CA1 region of the hippocampus, moderate to severe loss in mid-dorsal posterior hippocampus, and less damage to the dorsolateral striatum. These results suggest that the PI animal is a reasonable model for the permanent behavioral impairment and pathologic damage found in some human survivors of cardiac arrest.

  12. Specification of Region-Specific Neurons Including Forebrain Glutamatergic Neurons from Human Induced Pluripotent Stem Cells

    Science.gov (United States)

    Martins-Taylor, Kristen; Wang, Xiaofang; Zhang, Zheng; Park, Jung Woo; Zhan, Shuning; Kronenberg, Mark S.; Lichtler, Alexander; Liu, Hui-Xia; Chen, Fang-Ping; Yue, Lixia; Li, Xue-Jun; Xu, Ren-He

    2010-01-01

    Background Directed differentiation of human induced pluripotent stem cells (hiPSC) into functional, region-specific neural cells is a key step to realizing their therapeutic promise to treat various neural disorders, which awaits detailed elucidation. Methodology/Principal Findings We analyzed neural differentiation from various hiPSC lines generated by others and ourselves. Although heterogeneity in efficiency of neuroepithelial (NE) cell differentiation was observed among different hiPSC lines, the NE differentiation process resembles that from human embryonic stem cells (hESC) in morphology, timing, transcriptional profile, and requirement for FGF signaling. NE cells differentiated from hiPSC, like those from hESC, can also form rostral phenotypes by default, and form the midbrain or spinal progenitors upon caudalization by morphogens. The rostrocaudal neural progenitors can further mature to develop forebrain glutamatergic projection neurons, midbrain dopaminergic neurons, and spinal motor neurons, respectively. Typical ion channels and action potentials were recorded in the hiPSC-derived neurons. Conclusions/Significance Our results demonstrate that hiPSC, regardless of how they were derived, can differentiate into a spectrum of rostrocaudal neurons with functionality, which supports the considerable value of hiPSC for study and treatment of patient-specific neural disorders. PMID:20686615

  13. Interaction of basal forebrain cholinergic neurons with the glucocorticoid system in stress regulation and cognitive impairment.

    Science.gov (United States)

    Paul, Saswati; Jeon, Won Kyung; Bizon, Jennifer L; Han, Jung-Soo

    2015-01-01

    A substantial number of studies on basal forebrain (BF) cholinergic neurons (BFCN) have provided compelling evidence for their role in the etiology of stress, cognitive aging, Alzheimer's disease (AD), and other neurodegenerative diseases. BFCN project to a broad range of cortical sites and limbic structures, including the hippocampus, and are involved in stress and cognition. In particular, the hippocampus, the primary target tissue of the glucocorticoid stress hormones, is associated with cognitive function in tandem with hypothalamic-pituitary-adrenal (HPA) axis modulation. The present review summarizes glucocorticoid and HPA axis research to date in an effort to establish the manner in which stress affects the release of acetylcholine (ACh), glucocorticoids, and their receptor in the context of cognitive processes. We attempt to provide the molecular interactive link between the glucocorticoids and cholinergic system that contributes to BFCN degeneration in stress-induced acceleration of cognitive decline in aging and AD. We also discuss the importance of animal models in facilitating such studies for pharmacological use, to which could help decipher disease states and propose leads for pharmacological intervention.

  14. Increased innervation of forebrain targets by midbrain dopaminergic neurons in the absence of FGF-2.

    Science.gov (United States)

    Rumpel, R; Baron, O; Ratzka, A; Schröder, M-L; Hohmann, M; Effenberg, A; Claus, P; Grothe, C

    2016-02-09

    Fibroblast growth factors (FGFs) regulate development and maintenance, and reduce vulnerability of neurons. FGF-2 is essential for survival of midbrain dopaminergic (DA) neurons and is responsible for their dysplasia and disease-related degeneration. We previously reported that FGF-2 is involved in adequate forebrain (FB) target innervation by these neurons in an organotypic co-culture model. It remains unclear, how this ex-vivo phenotype relates to the in vivo situation, and which FGF-related signaling pathway is involved in this process. Here, we demonstrate that lack of FGF-2 results in an increased volume of the striatal target area in mice. We further add evidence that the low molecular weight (LMW) FGF-2 isoform is responsible for this phenotype, as this isoform is predominantly expressed in the embryonic ventral midbrain (VM) as well as in postnatal striatum (STR) and known to act via canonical transmembrane FGF receptor (FGFR) activation. Additionally, we confirm that the phenotype with an enlarged FB-target area by DA neurons can be mimicked in an ex-vivo explant model by inhibiting the canonical FGFR signaling, which resulted in decreased extracellular signal-regulated kinase (ERK) activation, while AKT activation remained unchanged.

  15. Specification of region-specific neurons including forebrain glutamatergic neurons from human induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Hui Zeng

    Full Text Available BACKGROUND: Directed differentiation of human induced pluripotent stem cells (hiPSC into functional, region-specific neural cells is a key step to realizing their therapeutic promise to treat various neural disorders, which awaits detailed elucidation. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed neural differentiation from various hiPSC lines generated by others and ourselves. Although heterogeneity in efficiency of neuroepithelial (NE cell differentiation was observed among different hiPSC lines, the NE differentiation process resembles that from human embryonic stem cells (hESC in morphology, timing, transcriptional profile, and requirement for FGF signaling. NE cells differentiated from hiPSC, like those from hESC, can also form rostral phenotypes by default, and form the midbrain or spinal progenitors upon caudalization by morphogens. The rostrocaudal neural progenitors can further mature to develop forebrain glutamatergic projection neurons, midbrain dopaminergic neurons, and spinal motor neurons, respectively. Typical ion channels and action potentials were recorded in the hiPSC-derived neurons. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that hiPSC, regardless of how they were derived, can differentiate into a spectrum of rostrocaudal neurons with functionality, which supports the considerable value of hiPSC for study and treatment of patient-specific neural disorders.

  16. Comparison and optimization of hiPSC forebrain cortical differentiation protocols.

    Science.gov (United States)

    Muratore, Christina R; Srikanth, Priya; Callahan, Dana G; Young-Pearse, Tracy L

    2014-01-01

    Several protocols have been developed for human induced pluripotent stem cell neuronal differentiation. We compare several methods for forebrain cortical neuronal differentiation by assessing cell morphology, immunostaining and gene expression. We evaluate embryoid aggregate vs. monolayer with dual SMAD inhibition differentiation protocols, manual vs. AggreWell aggregate formation, plating substrates, neural progenitor cell (NPC) isolation methods, NPC maintenance and expansion, and astrocyte co-culture. The embryoid aggregate protocol, using a Matrigel substrate, consistently generates a high yield and purity of neurons. NPC isolation by manual selection, enzymatic rosette selection, or FACS all are efficient, but exhibit some differences in resulting cell populations. Expansion of NPCs as neural aggregates yields higher cell purity than expansion in a monolayer. Finally, co-culture of iPSC-derived neurons with astrocytes increases neuronal maturity by day 40. This study directly compares commonly employed methods for neuronal differentiation of iPSCs, and can be used as a resource for choosing between various differentiation protocols.

  17. Comparison and optimization of hiPSC forebrain cortical differentiation protocols.

    Directory of Open Access Journals (Sweden)

    Christina R Muratore

    Full Text Available Several protocols have been developed for human induced pluripotent stem cell neuronal differentiation. We compare several methods for forebrain cortical neuronal differentiation by assessing cell morphology, immunostaining and gene expression. We evaluate embryoid aggregate vs. monolayer with dual SMAD inhibition differentiation protocols, manual vs. AggreWell aggregate formation, plating substrates, neural progenitor cell (NPC isolation methods, NPC maintenance and expansion, and astrocyte co-culture. The embryoid aggregate protocol, using a Matrigel substrate, consistently generates a high yield and purity of neurons. NPC isolation by manual selection, enzymatic rosette selection, or FACS all are efficient, but exhibit some differences in resulting cell populations. Expansion of NPCs as neural aggregates yields higher cell purity than expansion in a monolayer. Finally, co-culture of iPSC-derived neurons with astrocytes increases neuronal maturity by day 40. This study directly compares commonly employed methods for neuronal differentiation of iPSCs, and can be used as a resource for choosing between various differentiation protocols.

  18. Olfactory tubercle stimulation alters odor preference behavior and recruits forebrain reward and motivational centers

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    Brynn J FitzGerald

    2014-03-01

    Full Text Available Rodents show robust behavioral responses to odors, including strong preferences or aversions for certain odors. The neural mechanisms underlying the effects of odors on these behaviors in animals are not well understood. Here, we provide an initial proof-of-concept study into the role of the olfactory tubercle (OT, a structure with known anatomical connectivity with both brain reward and olfactory structures, in regulating odor-motivated behaviors. We implanted c57bl/6 male mice with an ipsilateral bipolar electrode into the OT to administer electric current and thereby yield gross activation of the OT. We confirmed that electrical stimulation of the OT was rewarding, with mice frequently self-administering stimulation on a fixed ratio schedule. In a separate experiment, mice were presented with either fox urine or peanut odors in a three-chamber preference test. In absence of OT stimulation, significant preference for the peanut odor chamber was observed which was abolished in the presence of OT stimulation. Perhaps providing a foundation for this modulation in behavior, we found that OT stimulation significantly increased the number of c-Fos positive neurons in not only the OT, but also in forebrain structures essential to motivated behaviors, including the nucleus accumbens and lateral septum. The present results support the notion that the OT is integral to the display of motivated behavior and possesses the capacity to modulate odor hedonics either by directly altering odor processing or perhaps by indirect actions on brain reward and motivation structures.

  19. Bidirectional Regulation of Innate and Learned Behaviors That Rely on Frequency Discrimination by Cortical Inhibitory Neurons.

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    Mark Aizenberg

    2015-12-01

    Full Text Available The ability to discriminate tones of different frequencies is fundamentally important for everyday hearing. While neurons in the primary auditory cortex (AC respond differentially to tones of different frequencies, whether and how AC regulates auditory behaviors that rely on frequency discrimination remains poorly understood. Here, we find that the level of activity of inhibitory neurons in AC controls frequency specificity in innate and learned auditory behaviors that rely on frequency discrimination. Photoactivation of parvalbumin-positive interneurons (PVs improved the ability of the mouse to detect a shift in tone frequency, whereas photosuppression of PVs impaired the performance. Furthermore, photosuppression of PVs during discriminative auditory fear conditioning increased generalization of conditioned response across tone frequencies, whereas PV photoactivation preserved normal specificity of learning. The observed changes in behavioral performance were correlated with bidirectional changes in the magnitude of tone-evoked responses, consistent with predictions of a model of a coupled excitatory-inhibitory cortical network. Direct photoactivation of excitatory neurons, which did not change tone-evoked response magnitude, did not affect behavioral performance in either task. Our results identify a new function for inhibition in the auditory cortex, demonstrating that it can improve or impair acuity of innate and learned auditory behaviors that rely on frequency discrimination.

  20. Discrimination of frequency variance for tonal sequencesa)

    OpenAIRE

    Byrne, Andrew J.; Viemeister, Neal F.; Stellmack, Mark A.

    2014-01-01

    Real-world auditory stimuli are highly variable across occurrences and sources. The present study examined the sensitivity of human listeners to differences in global stimulus variability. In a two-interval, forced-choice task, variance discrimination was measured using sequences of five 100-ms tone pulses. The frequency of each pulse was sampled randomly from a distribution that was Gaussian in logarithmic frequency. In the non-signal interval, the sampled distribution had a variance of σSTA...

  1. Detection of auditory signals in quiet and noisy backgrounds while performing a visuo-spatial task

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    Vishakha W Rawool

    2016-01-01

    Full Text Available Context: The ability to detect important auditory signals while performing visual tasks may be further compounded by background chatter. Thus, it is important to know how task performance may interact with background chatter to hinder signal detection. Aim: To examine any interactive effects of speech spectrum noise and task performance on the ability to detect signals. Settings and Design: The setting was a sound-treated booth. A repeated measures design was used. Materials and Methods: Auditory thresholds of 20 normal adults were determined at 0.5, 1, 2 and 4 kHz in the following conditions presented in a random order: (1 quiet with attention; (2 quiet with a visuo-spatial task or puzzle (distraction; (3 noise with attention and (4 noise with task. Statistical Analysis: Multivariate analyses of variance (MANOVA with three repeated factors (quiet versus noise, visuo-spatial task versus no task, signal frequency. Results: MANOVA revealed significant main effects for noise and signal frequency and significant noise–frequency and task–frequency interactions. Distraction caused by performing the task worsened the thresholds for tones presented at the beginning of the experiment and had no effect on tones presented in the middle. At the end of the experiment, thresholds (4 kHz were better while performing the task than those obtained without performing the task. These effects were similar across the quiet and noise conditions. Conclusion: Detection of auditory signals is difficult at the beginning of a distracting visuo-spatial task but over time, task learning and auditory training effects can nullify the effect of distraction and may improve detection of high frequency sounds.

  2. Psychoacoustic characteristics of tinnitus in individuals with auditory neuropathy spectrum disorder

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    P. Prashanth Prabhu

    2014-03-01

    Full Text Available The study aimed at understanding the psychoacoustic characteristics of tinnitus in individuals with auditory neuropathy spectrum disorder (ANSD. It attempts to assess the pitch and intensity of loudness of tinnitus matched by individuals with ANSD. Fifty individuals who were diagnosed as having auditory neuropathy spectrum disorder were included in the study. Tinnitus evaluation was carried out where the individuals matched the frequency and intensity of loudness of the tinnitus. The results of the study shows that pitch matched by majority of patients with ANSD is predominantly low pitched (<1000 Hz. The frequency of tinnitus matched by the patients with ANSD also correlated with the degree of maximal hearing loss. The intensity of loudness of the tinnitus was around 10-15 dB higher than their threshold in majority of the patients considered in the study. There was a weak negative correlation for the matched frequency and intensity of loudness. The results of the study suggest that majority of individuals with low frequency hearing loss had low pitched tinnitus. Thus, there could be discordant damage between outer and inner hair cells, abnormal firing of auditory nerve in individuals with ANSD which can lead to tinnitus. Thus, it can help to understand the physiology of tinnitus in individuals with ANSD.

  3. Experience and information loss in auditory and visual memory.

    Science.gov (United States)

    Gloede, Michele E; Paulauskas, Emily E; Gregg, Melissa K

    2017-07-01

    Recent studies show that recognition memory for sounds is inferior to memory for pictures. Four experiments were conducted to examine the nature of auditory and visual memory. Experiments 1-3 were conducted to evaluate the role of experience in auditory and visual memory. Participants received a study phase with pictures/sounds, followed by a recognition memory test. Participants then completed auditory training with each of the sounds, followed by a second memory test. Despite auditory training in Experiments 1 and 2, visual memory was superior to auditory memory. In Experiment 3, we found that it is possible to improve auditory memory, but only after 3 days of specific auditory training and 3 days of visual memory decay. We examined the time course of information loss in auditory and visual memory in Experiment 4 and found a trade-off between visual and auditory recognition memory: Visual memory appears to have a larger capacity, while auditory memory is more enduring. Our results indicate that visual and auditory memory are inherently different memory systems and that differences in visual and auditory recognition memory performance may be due to the different amounts of experience with visual and auditory information, as well as structurally different neural circuitry specialized for information retention.

  4. Coding of communication calls in the subcortical and cortical structures of the auditory system.

    Science.gov (United States)

    Suta, D; Popelár, J; Syka, J

    2008-01-01

    The processing of species-specific communication signals in the auditory system represents an important aspect of animal behavior and is crucial for its social interactions, reproduction, and survival. In this article the neuronal mechanisms underlying the processing of communication signals in the higher centers of the auditory system--inferior colliculus (IC), medial geniculate body (MGB) and auditory cortex (AC)--are reviewed, with particular attention to the guinea pig. The selectivity of neuronal responses for individual calls in these auditory centers in the guinea pig is usually low--most neurons respond to calls as well as to artificial sounds; the coding of complex sounds in the central auditory nuclei is apparently based on the representation of temporal and spectral features of acoustical stimuli in neural networks. Neuronal response patterns in the IC reliably match the sound envelope for calls characterized by one or more short impulses, but do not exactly fit the envelope for long calls. Also, the main spectral peaks are represented by neuronal firing rates in the IC. In comparison to the IC, response patterns in the MGB and AC demonstrate a less precise representation of the sound envelope, especially in the case of longer calls. The spectral representation is worse in the case of low-frequency calls, but not in the case of broad-band calls. The emotional content of the call may influence neuronal responses in the auditory pathway, which can be demonstrated by stimulation with time-reversed calls or by measurements performed under different levels of anesthesia. The investigation of the principles of the neural coding of species-specific vocalizations offers some keys for understanding the neural mechanisms underlying human speech perception.

  5. Brain state-dependent abnormal LFP activity in the auditory cortex of a schizophrenia mouse model.

    Science.gov (United States)

    Nakao, Kazuhito; Nakazawa, Kazu

    2014-01-01

    In schizophrenia, evoked 40-Hz auditory steady-state responses (ASSRs) are impaired, which reflects the sensory deficits in this disorder, and baseline spontaneous oscillatory activity also appears to be abnormal. It has been debated whether the evoked ASSR impairments are due to the possible increase in baseline power. GABAergic interneuron-specific NMDA receptor (NMDAR) hypofunction mutant mice mimic some behavioral and pathophysiological aspects of schizophrenia. To determine the presence and extent of sensory deficits in these mutant mice, we recorded spontaneous local field potential (LFP) activity and its click-train evoked ASSRs from primary auditory cortex of awake, head-restrained mice. Baseline spontaneous LFP power in the pre-stimulus period before application of the first click trains was augmented at a wide range of frequencies. However, when repetitive ASSR stimuli were presented every 20 s, averaged spontaneous LFP power amplitudes during the inter-ASSR stimulus intervals in the mutant mice became indistinguishable from the levels of control mice. Nonetheless, the evoked 40-Hz ASSR power and their phase locking to click trains were robustly impaired in the mutants, although the evoked 20-Hz ASSRs were also somewhat diminished. These results suggested that NMDAR hypofunction in cortical GABAergic neurons confers two brain state-dependent LFP abnormalities in the auditory cortex; (1) a broadband increase in spontaneous LFP power in the absence of external inputs, and (2) a robust deficit in the evoked ASSR power and its phase-locking despite of normal baseline LFP power magnitude during the repetitive auditory stimuli. The "paradoxically" high spontaneous LFP activity of the primary auditory cortex in the absence of external stimuli may possibly contribute to the emergence of schizophrenia-related aberrant auditory perception.

  6. Auditory and visual reaction time and peripheral field of vision in helmet users

    Directory of Open Access Journals (Sweden)

    Abbupillai Adhilakshmi

    2016-12-01

    Full Text Available Background: The incidence of fatal accidents are more in two wheeler drivers compared to four wheeler drivers. Head injury is of serious concern when recovery and prognosis of the patients are warranted, helmets are being used for safety purposes by moped, scooters and motorcycle drivers. Although, helmets are designed with cushioning effect to prevent head injuries but there are evidences of increase risk of neck injuries and reduced peripheral vision and hearing in helmet users. A complete full coverage helmets provide about less than 3 percent restrictions in horizontal peripheral visual field compared to rider without helmet. The standard company patented ergonomically designed helmets which does not affect the peripheral vision neither auditory reaction time. Objective: This pilot study aimed to evaluate the peripheral field of vision and auditory and visual reaction time in a hypertensive, diabetic and healthy male and female in order to have a better insight of protective characteristics of helmet in health and disease. Method: This pilot study carried out on age matched male of one healthy, one hypertensive and one diabetic and female subject of one healthy, one hypertensive and one diabetics. The field of vision was assessed by Lister’s perimeter whereas auditory and visual reaction time was recorded with response analyser. Result : Gender difference was not noted in peripheral field of vision but mild difference was found in auditory reaction time for high frequency and visual reaction time for both red and green colour in healthy control. But lateral and downward peripheral visual field was found reduced whereas auditory and visual reaction time was found increased in both hypertensive and diabetic subject in both sexes. Conclusion: Peripheral vision, auditory reaction time and visual reaction time in hypertensive and diabetics may lead to vulnerable accident. Helmet use has proven to reduce extent of injury in motorcyclist and

  7. Brain state-dependent abnormal LFP activity in the auditory cortex of a schizophrenia mouse model

    Directory of Open Access Journals (Sweden)

    Kazuhito eNakao

    2014-07-01

    Full Text Available In schizophrenia, evoked 40-Hz auditory steady-state responses (ASSRs are impaired, which reflects the sensory deficits in this disorder, and baseline spontaneous oscillatory activity also appears to be abnormal. It has been debated whether the evoked ASSR impairments are due to the possible increase in baseline power. GABAergic interneuron-specific NMDA receptor (NMDAR hypofunction mutant mice mimic some behavioral and pathophysiological aspects of schizophrenia. To determine the presence and extent of sensory deficits in these mutant mice, we recorded spontaneous local field potential (LFP activity and its click-train evoked ASSRs from primary auditory cortex of awake, head-restrained mice. Baseline spontaneous LFP power in the pre-stimulus period before application of the first click trains was augmented at a wide range of frequencies. However, when repetitive ASSR stimuli were presented every 20 sec, averaged spontaneous LFP power amplitudes during the inter-ASSR stimulus intervals in the mutant mice became indistinguishable from the levels of control mice. Nonetheless, the evoked 40-Hz ASSR power and their phase locking to click trains were robustly impaired in the mutants, although the evoked 20-Hz ASSRs were also somewhat diminished. These results suggested that NMDAR hypofunction in cortical GABAergic neurons confers two brain state-dependent LFP abnormalities in the auditory cortex; (1 a broadband increase in spontaneous LFP power in the absence of external inputs, and (2 a robust deficit in the evoked ASSR power and its phase-locking despite of normal baseline LFP power magnitude during the repetitive auditory stimuli. The paradoxically high spontaneous LFP activity of the primary auditory cortex in the absence of external stimuli may possibly contribute to the emergence of schizophrenia-related aberrant auditory perception.

  8. Effects of Caffeine on Auditory Brainstem Response

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    Saleheh Soleimanian

    2008-06-01

    Full Text Available Background and Aim: Blocking of the adenosine receptor in central nervous system by caffeine can lead to increasing the level of neurotransmitters like glutamate. As the adenosine receptors are present in almost all brain areas like central auditory pathway, it seems caffeine can change conduction in this way. The purpose of this study was to evaluate the effects of caffeine on latency and amplitude of auditory brainstem response(ABR.Materials and Methods: In this clinical trial study 43 normal 18-25 years old male students were participated. The subjects consumed 0, 2 and 3 mg/kg BW caffeine in three different sessions. Auditory brainstem responses were recorded before and 30 minute after caffeine consumption. The results were analyzed by Friedman and Wilcoxone test to assess the effects of caffeine on auditory brainstem response.Results: Compared to control group the latencies of waves III,V and I-V interpeak interval of the cases decreased significantly after 2 and 3mg/kg BW caffeine consumption. Wave I latency significantly decreased after 3mg/kg BW caffeine consumption(p<0.01. Conclusion: Increasing of the glutamate level resulted from the adenosine receptor blocking brings about changes in conduction in the central auditory pathway.

  9. Facilitated auditory detection for speech sounds.

    Science.gov (United States)

    Signoret, Carine; Gaudrain, Etienne; Tillmann, Barbara; Grimault, Nicolas; Perrin, Fabien

    2011-01-01

    If it is well known that knowledge facilitates higher cognitive functions, such as visual and auditory word recognition, little is known about the influence of knowledge on detection, particularly in the auditory modality. Our study tested the influence of phonological and lexical knowledge on auditory detection. Words, pseudo-words, and complex non-phonological sounds, energetically matched as closely as possible, were presented at a range of presentation levels from sub-threshold to clearly audible. The participants performed a detection task (Experiments 1 and 2) that was followed by a two alternative forced-choice recognition task in Experiment 2. The results of this second task in Experiment 2 suggest a correct recognition of words in the absence of detection with a subjective threshold approach. In the detection task of both experiments, phonological stimuli (words and pseudo-words) were better detected than non-phonological stimuli (complex sounds), presented close to the auditory threshold. This finding suggests an advantage of speech for signal detection. An additional advantage of words over pseudo-words was observed in Experiment 2, suggesting that lexical knowledge could also improve auditory detection when listeners had to recognize the stimulus in a subsequent task. Two simulations of detection performance performed on the sound signals confirmed that the advantage of speech over non-speech processing could not be attributed to energetic differences in the stimuli.

  10. Facilitated auditory detection for speech sounds

    Directory of Open Access Journals (Sweden)

    Carine eSignoret

    2011-07-01

    Full Text Available If it is well known that knowledge facilitates higher cognitive functions, such as visual and auditory word recognition, little is known about the influence of knowledge on detection, particularly in the auditory modality. Our study tested the influence of phonological and lexical knowledge on auditory detection. Words, pseudo words and complex non phonological sounds, energetically matched as closely as possible, were presented at a range of presentation levels from sub threshold to clearly audible. The participants performed a detection task (Experiments 1 and 2 that was followed by a two alternative forced choice recognition task in Experiment 2. The results of this second task in Experiment 2 suggest a correct recognition of words in the absence of detection with a subjective threshold approach. In the detection task of both experiments, phonological stimuli (words and pseudo words were better detected than non phonological stimuli (complex sounds, presented close to the auditory threshold. This finding suggests an advantage of speech for signal detection. An additional advantage of words over pseudo words was observed in Experiment 2, suggesting that lexical knowledge could also improve auditory detection when listeners had to recognize the stimulus in a subsequent task. Two simulations of detection performance performed on the sound signals confirmed that the advantage of speech over non speech processing could not be attributed to energetic differences in the stimuli.

  11. Absence of auditory 'global interference' in autism.

    Science.gov (United States)

    Foxton, Jessica M; Stewart, Mary E; Barnard, Louise; Rodgers, Jacqui; Young, Allan H; O'Brien, Gregory; Griffiths, Timothy D

    2003-12-01

    There has been considerable recent interest in the cognitive style of individuals with Autism Spectrum Disorder (ASD). One theory, that of weak central coherence, concerns an inability to combine stimulus details into a coherent whole. Here we test this theory in the case of sound patterns, using a new definition of the details (local structure) and the coherent whole (global structure). Thirteen individuals with a diagnosis of autism or Asperger's syndrome and 15 control participants were administered auditory tests, where they were required to match local pitch direction changes between two auditory sequences. When the other local features of the sequence pairs were altered (the actual pitches and relative time points of pitch direction change), the control participants obtained lower scores compared with when these details were left unchanged. This can be attributed to interference from the global structure, defined as the combination of the local auditory details. In contrast, the participants with ASD did not obtain lower scores in the presence of such mismatches. This was attributed to the absence of interference from an auditory coherent whole. The results are consistent with the presence of abnormal interactions between local and global auditory perception in ASD.

  12. Expression and function of scleraxis in the developing auditory system.

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    Zoe F Mann

    Full Text Available A study of genes expressed in the developing inner ear identified the bHLH transcription factor Scleraxis (Scx in the developing cochlea. Previous work has demonstrated an essential role for Scx in the differentiation and development of tendons, ligaments and cells of chondrogenic lineage. Expression in the cochlea has been shown previously, however the functional role for Scx in the cochlea is unknown. Using a Scx-GFP reporter mouse line we examined the spatial and temporal patterns of Scx expression in the developing cochlea between embryonic day 13.5 and postnatal day 25. Embryonically, Scx is expressed broadly throughout the cochlear duct and surrounding mesenchyme and at postnatal ages becomes restricted to the inner hair cells and the interdental cells of the spiral limbus. Deletion of Scx results in hearing impairment indicated by elevated auditory brainstem response (ABR thresholds and diminished distortion product otoacoustic emission (DPOAE amplitudes, across a range of frequencies. No changes in either gross cochlear morphology or expression of the Scx target genes Col2A, Bmp4 or Sox9 were observed in Scx(-/- mutants, suggesting that the auditory defects observed in these animals may be a result of unidentified Scx-dependent processes within the cochlea.

  13. Auditory Brainstem Responses in Children Treated with Cisplatin

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    Mohammad Kamali

    2012-03-01

    Full Text Available Background and Aim: In view of improvement in therapeutic outcome of cancer treatment in children resulting in increased survival rates and the importance of hearing in speech and language development, this research project was intended to assess the effects of cisplatin group on hearing ability in children aged 6 months to 12 years.Methods: In this cross-sectional study, hearing of 10 children on cisplatin group medication for cancer who met the inclusion criteria was examined by recording auditory brainstem responses (ABR using the three stimulants of click and 4 and 8 kHz tone bursts. All children were examined twice: before drug administration and within 72 hours after receiving the last dose. Then the results were compared with each other.Results: There was a significant difference between hearing thresholds before and after drug administration (p<0.05. Right and left ear threshold comparison revealed no significant difference.Conclusion: Ototoxic effects of cisplatin group were confirmed in this study. Insignificant difference observed in comparing right and left ear hearing thresholds could be due to small sample size. auditory brainstem responses test especially with frequency specificity proved to be a useful method in assessing cisplatin ototoxicity.

  14. New perspectives on the auditory cortex: learning and memory.

    Science.gov (United States)

    Weinberger, Norman M

    2015-01-01

    Primary ("early") sensory cortices have been viewed as stimulus analyzers devoid of function in learning, memory, and cognition. However, studies combining sensory neurophysiology and learning protocols have revealed that associative learning systematically modifies the encoding of stimulus dimensions in the primary auditory cortex (A1) to accentuate behaviorally important sounds. This "representational plasticity" (RP) is manifest at different levels. The sensitivity and selectivity of signal tones increase near threshold, tuning above threshold shifts toward the frequency of acoustic signals, and their area of representation can increase within the tonotopic map of A1. The magnitude of area gain encodes the level of behavioral stimulus importance and serves as a substrate of memory strength. RP has the same characteristics as behavioral memory: it is associative, specific, develops rapidly, consolidates, and can last indefinitely. Pairing tone with stimulation of the cholinergic nucleus basalis induces RP and implants specific behavioral memory, while directly increasing the representational area of a tone in A1 produces matching behavioral memory. Thus, RP satisfies key criteria for serving as a substrate of auditory memory. The findings suggest a basis for posttraumatic stress disorder in abnormally augmented cortical representations and emphasize the need for a new model of the cerebral cortex.

  15. The effect of background music in auditory health persuasion

    NARCIS (Netherlands)

    Elbert, Sarah; Dijkstra, Arie

    2013-01-01

    In auditory health persuasion, threatening information regarding health is communicated by voice only. One relevant context of auditory persuasion is the addition of background music. There are different mechanisms through which background music might influence persuasion, for example through mood (

  16. The role of temporal coherence in auditory stream segregation

    DEFF Research Database (Denmark)

    Christiansen, Simon Krogholt

    The ability to perceptually segregate concurrent sound sources and focus one’s attention on a single source at a time is essential for the ability to use acoustic information. While perceptual experiments have determined a range of acoustic cues that help facilitate auditory stream segregation......, it is not clear how the auditory system realizes the task. This thesis presents a study of the mechanisms involved in auditory stream segregation. Through a combination of psychoacoustic experiments, designed to characterize the influence of acoustic cues on auditory stream formation, and computational models...... of auditory processing, the role of auditory preprocessing and temporal coherence in auditory stream formation was evaluated. The computational model presented in this study assumes that auditory stream segregation occurs when sounds stimulate non-overlapping neural populations in a temporally incoherent...

  17. Auditory imagery and the poor-pitch singer.

    Science.gov (United States)

    Pfordresher, Peter Q; Halpern, Andrea R

    2013-08-01

    The vocal imitation of pitch by singing requires one to plan laryngeal movements on the basis of anticipated target pitch events. This process may rely on auditory imagery, which has been shown to activate motor planning areas. As such, we hypothesized that poor-pitch singing, although not typically associated with deficient pitch perception, may be associated with deficient auditory imagery. Participants vocally imitated simple pitch sequences by singing, discriminated pitch pairs on the basis of pitch height, and completed an auditory imagery self-report questionnaire (the Bucknell Auditory Imagery Scale). The percentage of trials participants sung in tune correlated significantly with self-reports of vividness for auditory imagery, although not with the ability to control auditory imagery. Pitch discrimination was not predicted by auditory imagery scores. The results thus support a link between auditory imagery and vocal imitation.

  18. Intradermal melanocytic nevus of the external auditory canal.

    Science.gov (United States)

    Alves, Renato V; Brandão, Fabiano H; Aquino, José E P; Carvalho, Maria R M S; Giancoli, Suzana M; Younes, Eduado A P

    2005-01-01

    Intradermal nevi are common benign pigmented skin tumors. Their occurrence within the external auditory canal is uncommon. The clinical and pathologic features of an intradermal nevus arising within the external auditory canal are presented, and the literature reviewed.

  19. Stimulus-specific adaptation and deviance detection in the rat auditory cortex.

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    Nevo Taaseh

    Full Text Available Stimulus-specific adaptation (SSA is the specific decrease in the response to a frequent ('standard' stimulus, which does not generalize, or generalizes only partially, to another, rare stimulus ('deviant'. Stimulus-specific adaptation could result simply from the depression of the responses to the standard. Alternatively, there may be an increase in the responses to the deviant stimulus due to the violation of expectations set by the standard, indicating the presence of true deviance detection. We studied SSA in the auditory cortex of halothane-anesthetized rats, recording local field potentials and multi-unit activity. We tested the responses to pure tones of one frequency when embedded in sequences that differed from each other in the frequency and probability of the tones composing them. The responses to tones of the same frequency were larger when deviant than when standard, even with inter-stimulus time intervals of almost 2 seconds. Thus, SSA is present and strong in rat auditory cortex. SSA was present even when the frequency difference between deviants and standards was as small as 10%, substantially smaller than the typical width of cortical tuning curves, revealing hyper-resolution in frequency. Strong responses were evoked also by a rare tone presented by itself, and by rare tones presented as part of a sequence of many widely spaced frequencies. On the other hand, when presented within a sequence of narrowly spaced frequencies, the responses to a tone, even when rare, were smaller. A model of SSA that included only adaptation of the responses in narrow frequency channels predicted responses to the deviants that were substantially smaller than the observed ones. Thus, the response to a deviant is at least partially due to the change it represents relative to the regularity set by the standard tone, indicating the presence of true deviance detection in rat auditory cortex.

  20. Auditory performances of a 3-4-7 programmable numeric filter hearing aid.

    Science.gov (United States)

    Chouard, C H; Ouayoun, M; Meyer, B; Coudert, C; Sequeville, T; Bachelot, G; Génin, J

    1997-01-01

    We designed a non-portable prototype seven-filter digital auditory hearing aid. For each of the filters, frequency bandwidth, amplification and compression were programmable in order to adapt these parameters to the deaf patient's audiometric characteristics. We compared the hearing improvement it was possible to obtain either with the three-analogue filter auditory prosthesis Triton 3004 hearing aid from Siemens or with our prototype as a function of the number of filters (three, four or seven) and their frequency bandwidth programmability. We tested 21 patients suffering from moderate to severe sensorineural hearing loss. This study allowed us to demonstrate that a seven programmable-width filter strategy seems to be more effective than the present analogue T004 device. Further studies with improvement of our prototype and finer audiometric adjustment of filter strategies, together with long-term clinical studies, need to be carried out.

  1. Visual Deprivation Causes Refinement of Intracortical Circuits in the Auditory Cortex

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    Xiangying Meng

    2015-08-01

    Full Text Available Loss of a sensory modality can lead to functional enhancement of the remaining senses. For example, short-term visual deprivations, or dark exposure (DE, can enhance neuronal responses in the auditory cortex to sounds. These enhancements encompass increased spiking rates and frequency selectivity as well as increased spiking reliability. Although we previously demonstrated enhanced thalamocortical transmission after DE, increased synaptic strength cannot account for increased frequency selectivity or reliability. We thus investigated whether other changes in the underlying circuitry contributed to improved neuronal responses. We show that DE can lead to refinement of intra- and inter-laminar connections in the mouse auditory cortex. Moreover, we use a computational model to show that the combination of increased transmission and circuit refinement can lead to increased firing reliability. Thus cross-modal influences can alter the spectral and temporal processing of sensory stimuli by refinement of thalamocortical and intracortical circuits.

  2. What determines auditory distraction? On the roles of local auditory changes and expectation violations.

    Directory of Open Access Journals (Sweden)

    Jan P Röer

    Full Text Available Both the acoustic variability of a distractor sequence and the degree to which it violates expectations are important determinants of auditory distraction. In four experiments we examined the relative contribution of local auditory changes on the one hand and expectation violations on the other hand in the disruption of serial recall by irrelevant sound. We present evidence for a greater disruption by auditory sequences ending in unexpected steady state distractor repetitions compared to auditory sequences with expected changing state endings even though the former contained fewer local changes. This effect was demonstrated with piano melodies (Experiment 1 and speech distractors (Experiment 2. Furthermore, it was replicated when the expectation violation occurred after the encoding of the target items (Experiment 3, indicating that the items' maintenance in short-term memory was disrupted by attentional capture and not their encoding. This seems to be primarily due to the violation of a model of the specific auditory distractor sequences because the effect vanishes and even reverses when the experiment provides no opportunity to build up a specific neural model about the distractor sequence (Experiment 4. Nevertheless, the violation of abstract long-term knowledge about auditory regularities seems to cause a small and transient capture effect: Disruption decreased markedly over the course of the experiments indicating that participants habituated to the unexpected distractor repetitions across trials. The overall pattern of results adds to the growing literature that the degree to which auditory distractors violate situation-specific expectations is a more important determinant of auditory distraction than the degree to which a distractor sequence contains local auditory changes.

  3. ABR and auditory P300 findings inchildren with ADHD

    OpenAIRE

    Schochat Eliane; Scheuer Claudia Ines; Andrade Ênio Roberto de

    2002-01-01

    Auditory processing disorders (APD), also referred as central auditory processing disorders (CAPD) and attention deficit hyperactivity disorders (ADHD) have become popular diagnostic entities for school age children. It has been demonstrated a high incidence of comorbid ADHD with communication disorders and auditory processing disorder. The aim of this study was to investigate ABR and P300 auditory evoked potentials in children with ADHD, in a double-blind study. Twenty-one children, ages bet...

  4. Auditory and motor imagery modulate learning in music performance

    Directory of Open Access Journals (Sweden)

    Rachel M. Brown

    2013-07-01

    Full Text Available Skilled performers such as athletes or musicians can improve their performance by imagining the actions or sensory outcomes associated with their skill. Performers vary widely in their auditory and motor imagery abilities, and these individual differences influence sensorimotor learning. It is unknown whether imagery abilities influence both memory encoding and retrieval. We examined how auditory and motor imagery abilities influence musicians’ encoding (during Learning, as they practiced novel melodies, and retrieval (during Recall of those melodies. Pianists learned melodies by listening without performing (auditory learning or performing without sound (motor learning; following Learning, pianists performed the melodies from memory with auditory feedback (Recall. During either Learning (Experiment 1 or Recall (Experiment 2, pianists experienced either auditory interference, motor interference, or no interference. Pitch accuracy (percentage of correct pitches produced and temporal regularity (variability of quarter-note interonset intervals were measured at Recall. Independent tests measured auditory and motor imagery skills. Pianists’ pitch accuracy was higher following auditory learning than following motor learning and lower in motor interference conditions (Experiments 1 and 2. Both auditory and motor imagery skills improved pitch accuracy overall. Auditory imagery skills modulated pitch accuracy encoding (Experiment 1: Higher auditory imagery skill corresponded to higher pitch accuracy following auditory learning with auditory or motor interference, and following motor learning with motor or no interference. These findings suggest that auditory imagery abilities decrease vulnerability to interference and compensate for missing auditory feedback at encoding. Auditory imagery skills also influenced temporal regularity at retrieval (Experiment 2: Higher auditory imagery skill predicted greater temporal regularity during Recall in the

  5. Phonetic categorization in auditory word perception.

    Science.gov (United States)

    Ganong, W F

    1980-02-01

    To investigate the interaction in speech perception of auditory information and lexical knowledge (in particular, knowledge of which phonetic sequences are words), acoustic continua varying in voice onset time were constructed so that for each acoustic continuum, one of the two possible phonetic categorizations made a word and the other did not. For example, one continuum ranged between the word dash and the nonword tash; another used the nonword dask and the word task. In two experiments, subjects showed a significant lexical effect--that is, a tendency to make phonetic categorizations that make words. This lexical effect was greater at the phoneme boundary (where auditory information is ambiguous) than at the ends of the condinua. Hence the lexical effect must arise at a stage of processing sensitive to both lexical knowledge and auditory information.

  6. [Functional neuroimaging of auditory hallucinations in schizophrenia].

    Science.gov (United States)

    Font, M; Parellada, E; Fernández-Egea, E; Bernardo, M; Lomeña, F

    2003-01-01

    The neurobiological bases underlying the generation of auditory hallucinations, a distressing and paradigmatic symptom of schizophrenia, are still unknown in spite of in-depth phenomenological descriptions. This work aims to make a critical review of the latest published literature in recent years, focusing on functional neuroimaging studies (PET, SPECT, fMRI) of auditory hallucinations. Thus, the studies are classified according to whether they are sensory activation, trait and state. The two main hypotheses proposed to explain the phenomenon, external speech vs. subvocal or inner speech, are also explained. Finally, the latest unitary theory as well as the limitations the studies published are commented on. The need to continue investigating in this field, that is still underdeveloped, is posed in order to understand better the etiopathogenesis of auditory hallucinations in schizophrenia.

  7. The mitochondrial connection in auditory neuropathy.

    Science.gov (United States)

    Cacace, Anthony T; Pinheiro, Joaquim M B

    2011-01-01

    'Auditory neuropathy' (AN), the term used to codify a primary degeneration of the auditory nerve, can be linked directly or indirectly to mitochondrial dysfunction. These observations are based on the expression of AN in known mitochondrial-based neurological diseases (Friedreich's ataxia, Mohr-Tranebjærg syndrome), in conditions where defects in axonal transport, protein trafficking, and fusion processes perturb and/or disrupt mitochondrial dynamics (Charcot-Marie-Tooth disease, autosomal dominant optic atrophy), in a common neonatal condition known to be toxic to mitochondria (hyperbilirubinemia), and where respiratory chain deficiencies produce reductions in oxidative phosphorylation that adversely affect peripheral auditory mechanisms. This body of evidence is solidified by data derived from temporal bone and genetic studies, biochemical, molecular biologic, behavioral, electroacoustic, and electrophysiological investigations.

  8. The auditory hallucination: a phenomenological survey.

    Science.gov (United States)

    Nayani, T H; David, A S

    1996-01-01

    A comprehensive semi-structured questionnaire was administered to 100 psychotic patients who had experienced auditory hallucinations. The aim was to extend the phenomenology of the hallucination into areas of both form and content and also to guide future theoretical development. All subjects heard 'voices' talking to or about them. The location of the voice, its characteristics and the nature of address were described. Precipitants and alleviating factors plus the effect of the hallucinations on the sufferer were identified. Other hallucinatory experiences, thought insertion and insight were examined for their inter-relationships. A pattern emerged of increasing complexity of the auditory-verbal hallucination over time by a process of accretion, with the addition of more voices and extended dialogues, and more intimacy between subject and voice. Such evolution seemed to relate to the lessening of distress and improved coping. These findings should inform both neurological and cognitive accounts of the pathogenesis of auditory hallucinations in psychotic disorders.

  9. Cooperative dynamics in auditory brain response

    CERN Document Server

    Kwapien, J; Liu, L C; Ioannides, A A

    1998-01-01

    Simultaneous estimates of the activity in the left and right auditory cortex of five normal human subjects were extracted from Multichannel Magnetoencephalography recordings. Left, right and binaural stimulation were used, in separate runs, for each subject. The resulting time-series of left and right auditory cortex activity were analysed using the concept of mutual information. The analysis constitutes an objective method to address the nature of inter-hemispheric correlations in response to auditory stimulations. The results provide a clear evidence for the occurrence of such correlations mediated by a direct information transport, with clear laterality effects: as a rule, the contralateral hemisphere leads by 10-20ms, as can be seen in the average signal. The strength of the inter-hemispheric coupling, which cannot be extracted from the average data, is found to be highly variable from subject to subject, but remarkably stable for each subject.

  10. Auditory temporal processes in the elderly

    Directory of Open Access Journals (Sweden)

    E. Ben-Artzi

    2011-03-01

    Full Text Available Several studies have reported age-related decline in auditory temporal resolution and in working memory. However, earlier studies did not provide evidence as to whether these declines reflect overall changes in the same mechanisms, or reflect age-related changes in two independent mechanisms. In the current study we examined whether the age-related decline in auditory temporal resolution and in working memory would remain significant even after controlling for their shared variance. Eighty-two participants, aged 21-82 performed the dichotic temporal order judgment task and the backward digit span task. The findings indicate that age-related decline in auditory temporal resolution and in working memory are two independent processes.

  11. Dexamphetamine reduces auditory P3 delta power and phase-locking while increasing gamma power.

    Science.gov (United States)

    Albrecht, Matthew A; Price, Greg; Lee, Joseph; Iyyalol, Rajan; Martin-Iverson, Mathew T

    2012-10-01

    Auditory P3 amplitude reduction is one of the most robust and replicated findings in schizophrenia. Recent evidence suggests that these reductions are due to reductions in both power and phase-locking at delta and theta frequencies. We have previously shown that the auditory, but not visual, P3 is reduced in healthy participants given the catecholamine releasing agent dexamphetamine. Our aim was to determine whether the auditory P3 amplitude reduction induced by dexamphetamine has similar power and phase locking characteristics to that seen in schizophrenia. Forty-four healthy participants were given 0.45 mg/kg dexamphetamine and placebo, in a double-blinded, placebo-controlled, cross-over design. The task was a three-stimulus auditory odd-ball task, target stimuli were the major stimuli of interest. Individual target trials underwent wavelet analysis to give power and phase-locking of delta (3 Hz), theta (4-7 Hz), alpha (8-12 Hz), beta (13-30 Hz) and gamma (30-50 Hz) frequencies for a 50 ms time window centred around the peak of the target P3. Delta power around the P3 peak was significantly reduced when participants were given dexamphetamine. Delta phase-locking was also reduced but only when analysis was targeted at the location of the peak P3 amplitude. In contrast, theta power and phase-locking were not affected by dexamphetamine. These findings suggest that increased catecholamine activity may be responsible for the power and phase-locking reductions of the auditory P3 delta component in patients with schizophrenia. Interestingly, dexamphetamine significantly increased gamma power around the P3 peak. We attempt to link this finding with the gamma alterations that have been found in patients with schizophrenia.

  12. Utilising reinforcement learning to develop strategies for driving auditory neural implants

    Science.gov (United States)

    Lee, Geoffrey W.; Zambetta, Fabio; Li, Xiaodong; Paolini, Antonio G.

    2016-08-01

    Objective. In this paper we propose a novel application of reinforcement learning to the area of auditory neural stimulation. We aim to develop a simulation environment which is based off real neurological responses to auditory and electrical stimulation in the cochlear nucleus (CN) and inferior colliculus (IC) of an animal model. Using this simulator we implement closed loop reinforcement learning algorithms to determine which methods are most effective at learning effective acoustic neural stimulation strategies. Approach. By recording a comprehensive set of acoustic frequency presentations and neural responses from a set of animals we created a large database of neural responses to acoustic stimulation. Extensive electrical stimulation in the CN and the recording of neural responses in the IC provides a mapping of how the auditory system responds to electrical stimuli. The combined dataset is used as the foundation for the simulator, which is used to implement and test learning algorithms. Main results. Reinforcement learning, utilising a modified n-Armed Bandit solution, is implemented to demonstrate the model’s function. We show the ability to effectively learn stimulation patterns which mimic the cochlea’s ability to covert acoustic frequencies to neural activity. Time taken to learn effective replication using neural stimulation takes less than 20 min under continuous testing. Significance. These results show the utility of reinforcement learning in the field of neural stimulation. These results can be coupled with existing sound processing technologies to develop new auditory prosthetics that are adaptable to the recipients current auditory pathway. The same process can theoretically be abstracted to other sensory and motor systems to develop similar electrical replication of neural signals.

  13. Efficacy of slow repetitive transcranial magnetic stimulation in the treatment of resistant auditory hallucinations in schizophrenia : A meta-analysis

    NARCIS (Netherlands)

    Aleman, Andre; Sommer, Iris E.; Kahn, Rene S.

    2007-01-01

    Objective: Slow repetitive transcranial magnetic stimulation (rTMS), at a frequency of 1 Hz, has been proposed as a treatment for auditory hallucinations. Several studies have now been reported regarding the efficacy of TMS treatment, but results were inconsistent. Therefore, meta-analytic integrati

  14. Influence of the power-spectrum of the pre-stimulus EEG on the consecutive Auditory Evoked Potential in rats.

    NARCIS (Netherlands)

    Jongsma, M.L.A.; Quian Quiroga, R.; Rijn, C.M. van; Schaijk, W.J. van; Dirksen, R.; Coenen, A.M.L.

    2000-01-01

    Evoked Potentials (EPs) are responses that appear in the EEG due to external stimulation. Findings indicate that changes in EPs can be related to changes in frequencies of the pre-stimulus EEG. Auditory EPs of rats (n=8) were measured in reaction to tone-pip stimuli (90 dB, 10.2 kHz, ISI 2s, n=1500)

  15. An Objective Measurement of the Build-Up of Auditory Streaming and of Its Modulation by Attention

    Science.gov (United States)

    Thompson, Sarah K.; Carlyon, Robert P.; Cusack, Rhodri

    2011-01-01

    Three experiments studied auditory streaming using sequences of alternating "ABA" triplets, where "A" and "B" were 50-ms tones differing in frequency by [delta]f semitones and separated by 75-ms gaps. Experiment 1 showed that detection of a short increase in the gap between a B tone and the preceding A tone, imposed on one ABA triplet, was better…

  16. Acute auditory stimulation with different styles of music influences cardiac autonomic regulation in men

    OpenAIRE

    da Silva, Sheila Ap. F.; Guida, Heraldo L; Ana Marcia dos Santos Antonio; Luiz Carlos de Abreu; Monteiro, Carlos B. M.; Celso Ferreira; Ribeiro, Vivian F.; Viviani Barnabe; Silva, Sidney B; FERNANDO L.A. FONSECA; Fernando Adami; Marcio Petenusso; Raimundo, Rodrigo D; Valenti, Vitor E.

    2014-01-01

    Background: No clear evidence is available in the literature regarding the acute effect of different styles of music on cardiac autonomic control. Objectives: The present study aimed to evaluate the acute effects of classical baroque and heavy metal musical auditory stimulation on Heart Rate Variability (HRV) in healthy men. Patients and Methods: In this study, HRV was analyzed regarding time (SDNN, RMSSD, NN50, and pNN50) and frequency domain (LF, HF, and LF / HF) in 12 healthy men. ...

  17. Dynamic Range Adaptation to Spectral Stimulus Statistics in Human Auditory Cortex

    Science.gov (United States)

    Schlichting, Nadine; Obleser, Jonas

    2014-01-01

    Classically, neural adaptation refers to a reduction in response magnitude by sustained stimulation. In human electroencephalography (EEG), neural adaptation has been measured, for example, as frequency-specific response decrease by previous stimulation. Only recently and mainly based on animal studies, it has been suggested that statistical properties in the stimulation lead to adjustments of neural sensitivity and affect neural response adaptation. However, it is thus far unresolved which statistical parameters in the acoustic stimulation spectrum affect frequency-specific neural adaptation, and on which time scales the effects take place. The present human EEG study investigated the potential influence of the overall spectral range as well as the spectral spacing of the acoustic stimulation spectrum on frequency-specific neural adaptation. Tones randomly varying in frequency were presented passively and computational modeling of frequency-specific neural adaptation was used. Frequency-specific adaptation was observed for all presentation conditions. Critically, however, the spread of adaptation (i.e., degree of coadaptation) in tonotopically organized regions of auditory cortex changed with the spectral range of the acoustic stimulation. In contrast, spectral spacing did not affect the spread of frequency-specific adaptation. Therefore, changes in neural sensitivity in auditory cortex are directly coupled to the overall spectral range of the acoustic stimulation, which suggests that neural adjustments to spectral stimulus statistics occur over a time scale of multiple seconds. PMID:24381293

  18. Do dyslexics have auditory input processing difficulties?

    DEFF Research Database (Denmark)

    Poulsen, Mads

    2011-01-01

    Word production difficulties are well documented in dyslexia, whereas the results are mixed for receptive phonological processing. This asymmetry raises the possibility that the core phonological deficit of dyslexia is restricted to output processing stages. The present study investigated whether...... a group of dyslexics had word level receptive difficulties using an auditory lexical decision task with long words and nonsense words. The dyslexics were slower and less accurate than chronological age controls in an auditory lexical decision task, with disproportionate low performance on nonsense words...

  19. The many facets of auditory display

    Science.gov (United States)

    Blattner, Meera M.

    1995-01-01

    In this presentation we will examine some of the ways sound can be used in a virtual world. We make the case that many different types of audio experience are available to us. A full range of audio experiences include: music, speech, real-world sounds, auditory displays, and auditory cues or messages. The technology of recreating real-world sounds through physical modeling has advanced in the past few years allowing better simulation of virtual worlds. Three-dimensional audio has further enriched our sensory experiences.

  20. Glucose metabolism and neurogenesis in the gerbil hippocampus after transient forebrain ischemia

    Institute of Scientific and Technical Information of China (English)

    Dae Young Yoo; Kwon Young Lee; Joon Ha Park; Hyo Young Jung; Jong Whi Kim; Yeo Sung Yoon; Moo-Ho Won; Jung Hoon Choi; In Koo Hwang

    2016-01-01

    Recent evidence exists that glucose transporter 3 (GLUT3) plays an important role in the energy metabo-lism in the brain. Most previous studies have been conducted using focal or hypoxic ischemia models and have focused on changes in GLUT3 expression based on protein and mRNA levels rather than tissue levels. In the present study, we observed change in GLUT3 immunoreactivity in the adult gerbil hippocampus at various time points after 5 minutes of transient forebrain ischemia. In the sham-operated group, GLUT3 immunoreactivity in the hippocampal CA1 region was weak, in the pyramidal cells of the CA1 region in-creased in a time-dependent fashion 24 hours after ischemia, and in the hippocampal CA1 region decreased signiifcantly between 2 and 5 days after ischemia, with high level of GLUT3 immunoreactivity observed in the CA1 region 10 days after ischemia. In a double immunolfuorescence study using GLUT3 and gli-al-ifbrillary acidic protein (GFAP), we observed strong GLUT3 immunoreactivity in the astrocytes. GLUT3 immunoreactivity increased after ischemia and peaked 7 days in the dentate gyrus after ischemia/reperfu-sion. In a double immunolfuorescence study using GLUT3 and doublecortin (DCX), we observed low level of GLUT3 immunoreactivity in the differentiated neuroblasts of the subgranular zone of the dentate gyrus after ischemia. GLUT3 immunoreactivity in the sham-operated group was mainly detected in the subgran-ular zone of the dentate gyrus. These results suggest that the increase in GLUT3 immunoreactivity may be a compensatory mechanism to modulate glucose level in the hippocampal CA1 region and to promote adult neurogenesis in the dentate gyrus.

  1. Motivational salience signal in the basal forebrain is coupled with faster and more precise decision speed.

    Science.gov (United States)

    Avila, Irene; Lin, Shih-Chieh

    2014-03-01

    The survival of animals depends critically on prioritizing responses to motivationally salient stimuli. While it is generally believed that motivational salience increases decision speed, the quantitative relationship between motivational salience and decision speed, measured by reaction time (RT), remains unclear. Here we show that the neural correlate of motivational salience in the basal forebrain (BF), defined independently of RT, is coupled with faster and also more precise decision speed. In rats performing a reward-biased simple RT task, motivational salience was encoded by BF bursting response that occurred before RT. We found that faster RTs were tightly coupled with stronger BF motivational salience signals. Furthermore, the fraction of RT variability reflecting the contribution of intrinsic noise in the decision-making process was actively suppressed in faster RT distributions with stronger BF motivational salience signals. Artificially augmenting the BF motivational salience signal via electrical stimulation led to faster and more precise RTs and supports a causal relationship. Together, these results not only describe for the first time, to our knowledge, the quantitative relationship between motivational salience and faster decision speed, they also reveal the quantitative coupling relationship between motivational salience and more precise RT. Our results further establish the existence of an early and previously unrecognized step in the decision-making process that determines both the RT speed and variability of the entire decision-making process and suggest that this novel decision step is dictated largely by the BF motivational salience signal. Finally, our study raises the hypothesis that the dysregulation of decision speed in conditions such as depression, schizophrenia, and cognitive aging may result from the functional impairment of the motivational salience signal encoded by the poorly understood noncholinergic BF neurons.

  2. Expression of the cannabinoid receptor CB1 in distinct neuronal subpopulations in the adult mouse forebrain.

    Science.gov (United States)

    Marsicano, G; Lutz, B

    1999-12-01

    Cannabinoids can modulate motor behaviour, learning and memory, cognition and pain perception. These effects correlate with the expression of the cannabinoid receptor 1 (CB1) and with the presence of endogenous cannabinoids in the brain. In trying to obtain further insights into the mechanisms underlying the modulatory effects of cannabinoids, CB1-positive neurons were determined in the murine forebrain at a single cell resolution. We performed a double in situ hybridization study to detect mRNA of CB1 in combination with mRNA of glutamic acid decarboxylase 65k, neuropeptide cholecystokinin (CCK), parvalbumin, calretinin and calbindin D28k, respectively. Our results revealed that CB1-expressing cells can be divided into distinct neuronal subpopulations. There is a clear distinction between neurons containing CB1 mRNA either at high levels or low levels. The majority of high CB1-expressing cells are GABAergic (gamma-aminobutyric acid) neurons belonging mainly to the cholecystokinin-positive and parvalbumin-negative type of interneurons (basket cells) and, to a lower extent, to the calbindin D28k-positive mid-proximal dendritic inhibitory interneurons. Only a fraction of low CB1-expressing cells is GABAergic. In the hippocampus, amygdala and entorhinal cortex area, CB1 mRNA is present at low but significant levels in many non-GABAergic cells that can be considered as projecting principal neurons. Thus, a complex mechanism appears to underlie the modulatory effects of cannabinoids. They might act on principal glutamatergic circuits as well as modulate local GABAergic inhibitory circuits. CB1 is very highly coexpressed with CCK. It is known that cannabinoids and CCK often have opposite effects on behaviour and physiology. Therefore, we suggest that a putative cross-talk between cannabinoids and CCK might exist and will be relevant to better understanding of physiology and pharmacology of the cannabinoid system.

  3. Nitric oxide activates leak K+ currents in the presumed cholinergic neuron of basal forebrain.

    Science.gov (United States)

    Kang, Youngnam; Dempo, Yoshie; Ohashi, Atsuko; Saito, Mitsuru; Toyoda, Hiroki; Sato, Hajime; Koshino, Hisashi; Maeda, Yoshinobu; Hirai, Toshihiro

    2007-12-01

    Learning and memory are critically dependent on basal forebrain cholinergic (BFC) neuron excitability, which is modulated profoundly by leak K(+) channels. Many neuromodulators closing leak K(+) channels have been reported, whereas their endogenous opener remained unknown. We here demonstrate that nitric oxide (NO) can be the endogenous opener of leak K(+) channels in the presumed BFC neurons. Bath application of 1 mM S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, induced a long-lasting hyperpolarization, which was often interrupted by a transient depolarization. Soluble guanylyl cyclase inhibitors prevented SNAP from inducing hyperpolarization but allowed SNAP to cause depolarization, whereas bath application of 0.2 mM 8-bromoguanosine-3',5'-cyclomonophosphate (8-Br-cGMP) induced a similar long-lasting hyperpolarization alone. These observations indicate that the SNAP-induced hyperpolarization and depolarization are mediated by the cGMP-dependent and -independent processes, respectively. When examined with the ramp command pulse applied at -70 mV under the voltage-clamp condition, 8-Br-cGMP application induced the outward current that reversed at K(+) equilibrium potential (E(K)) and displayed Goldman-Hodgkin-Katz rectification, indicating the involvement of voltage-independent K(+) current. By contrast, SNAP application in the presumed BFC neurons either dialyzed with the GTP-free internal solution or in the presence of 10 muM Rp-8-bromo-beta-phenyl-1,N(2)-ethenoguanosine 3',5'-cyclic monophosphorothioate sodium salt, a protein kinase G (PKG) inhibitor, induced the inward current that reversed at potentials much more negative than E(K) and close to the reversal potential of Na(+)-K(+) pump current. These observations strongly suggest that NO activates leak K(+) channels through cGMP-PKG-dependent pathway to markedly decrease the excitability in BFC neurons, while NO simultaneously causes depolarization by the inhibition of Na(+)-K(+) pump through ATP