Auditory Cortex Function Research Articles

Lack of correlation between phonetic magnetic mismatch field and plasma d-serine levels in humans

ObjectiveUncovering molecular bases for auditory language processing in the human brain is a fundamental scientific challenge. The power and latency of the magnetic mismatch field (MMF) elicited by phoneme change, which are magnetoencephalographic indices of language function in its early stage of information processing, are theoretically thought to be modulated by N-methyl-d-aspartate-type glutamate receptor (NMDAR) function, but no study has yet assessed this possibility. We have thus sought to demonstrate an association between phonetic MMF power/latency and levels of plasma d-serine, an intrinsic co-agonist of glycine binding sites on NMDAR, in adults. MethodsThe MMF response to phoneme changes was recorded using 204-channel magnetoencephalography in 61 healthy, right-handed, Japanese adults. Plasma levels of d- and l-serine were measured for each participant. ResultsWe did not find a significant correlation between MMF power/latency and plasma serine levels. ConclusionsDespite a sufficient sample size, we failed to find an association between the physiological markers of the early stage of information processing of language in the auditory cortex and biomarkers indexing glutamatergic function. SignificanceOur study did not indicate that a molecular index of glutamatergic function could be a surrogate marker for the early stage of information processing of language in humans.

Evaluating Auditory Pathway by Electrical Auditory Middle Latency Response and Postoperative Hearing Rehabilitation

ABSTRACTObjective: To establish an effective detection method to evaluate auditory pathway in patients by electrical evoked middle latency response (EMLR) before artificial cochlear implantation, and to analyze the relationship between postoperative hearing rehabilitation and auditory cortex functions. Methods: Twenty-three patients with artificial cochlear implant were recruited. EMLR was measured after adjusting the depth of anesthesia. The electrical auditory brainstem response (EABR) mode with monopolar stimulation and two-phase alternating current square waves was selected. The parameters of EMLR waveforms were recorded by the EABR measurement system. Nerve response telemetry (NRT) was examined by measuring threshold level (T value) and comfortable level (C value) 1 month after power-on, and hearing and speech development was followed up 12 months later.Results: The detection rate of EMLR was 95.65%. The waveforms of EMLR were comparable to those of auditory middle latency response (AMLR), showing decreased latency and interval but similar amplitude. The induction rate of NRT was 69.23%, which was much lower than that of EMLR. The EMLR thresholds were significantly correlated to the T and C values, and were comparable to the T values numerically. The Spearman's r value between EMLR waveforms and CAP scores after using the cochlear implant for 12 months was 0.673 (P < 0.01). Conclusion: An effective detection method to measure EMLR before artificial cochlear implant was established. The thresholds of EMLR were lower than those of NRT. The method can be useful for objective evaluation of auditory cortex functions and postoperative hearing rehabilitation.

Mismatch negativity (MMN) to spatial deviants and behavioral spatial discrimination ability in the etiology of auditory verbal hallucinations and thought disorder in schizophrenia

Persistent auditory verbal hallucinations (AVH) in schizophrenia are increasingly tied to dysfunction at the level of auditory cortex. AVH may reflect in part misattribution of internally generated thoughts to external spatial locations. Here, we investigated the association between persistent AVH and spatial localization abilities assessed both behaviorally and by mismatch negativity (MMN) to location deviants. MethodsSpatial- and tonal- discrimination abilities were assessed in patients (n=20) and controls (n=20) using free-field tones. MMN was assessed to spatial-location-, pitch- and duration-deviants. AVH and thought disorder were assessed using clinical evaluation. ResultsAs predicted, patients showed significant reductions in behavioral spatial-discrimination (p<0.0001) and tone-matching (p<0.001) ability, along with impaired MMN generation to location (p<0.03) and pitch (p<0.05) deviants. Hallucinating (AVH+) and non-hallucinating (AVH−) subjects showed similar deficits in location MMN to left-hemifield stimuli (p<0.0001 vs. control). By contrast, AVH− patients differed significantly from controls (p=0.009) and AVH+ patients (p=0.018) for MMN to right-lateral hemifield (left auditory cortex) stimuli, whereas AVH+ patients showed paradoxically preserved MMN generation (p=0.99 vs. controls). Severity of thought disorder correlated with impaired spatial discrimination, especially to right-hemifield stimuli (p=0.013), but did not correlate significantly with MMN or tone matching deficits. ConclusionThese findings demonstrate a significant relationship between auditory cortical spatial localization abilities and AVH susceptibility, with relatively preserved function of left vs. right auditory cortex predisposing to more severe AVH, and support models that attribute persistent AVH to impaired source-monitoring. The findings suggest new approaches for therapeutic intervention for both AVH and thought disorder in schizophrenia.

Abnormal auditory synchronization in stuttering: A magnetoencephalographic study

In a previous magnetoencephalographic study, we showed both functional and structural reorganization of the right auditory cortex and impaired left auditory cortex function in people who stutter (PWS). In the present work, we reevaluated the same dataset to further investigate how the right and left auditory cortices interact to compensate for stuttering. We evaluated bilateral N100m latencies as well as indices of local and inter-hemispheric phase synchronization of the auditory cortices. The left N100m latency was significantly prolonged relative to the right N100m latency in PWS, while healthy control participants did not show any inter-hemispheric differences in latency. A phase-locking factor (PLF) analysis, which indicates the degree of local phase synchronization, demonstrated enhanced alpha-band synchrony in the right auditory area of PWS. A phase-locking value (PLV) analysis of inter-hemispheric synchronization demonstrated significant elevations in the beta band between the right and left auditory cortices in PWS. In addition, right PLF and PLVs were positively correlated with stuttering frequency in PWS. Taken together, our data suggest that increased right hemispheric local phase synchronization and increased inter-hemispheric phase synchronization are electrophysiological correlates of a compensatory mechanism for impaired left auditory processing in PWS.

Temporal asymmetries in auditory coding and perception reflect multi-layered nonlinearities.

Sound recognition relies not only on spectral cues, but also on temporal cues, as demonstrated by the profound impact of time reversals on perception of common sounds. To address the coding principles underlying such auditory asymmetries, we recorded a large sample of auditory cortex neurons using two-photon calcium imaging in awake mice, while playing sounds ramping up or down in intensity. We observed clear asymmetries in cortical population responses, including stronger cortical activity for up-ramping sounds, which matches perceptual saliency assessments in mice and previous measures in humans. Analysis of cortical activity patterns revealed that auditory cortex implements a map of spatially clustered neuronal ensembles, detecting specific combinations of spectral and intensity modulation features. Comparing different models, we show that cortical responses result from multi-layered nonlinearities, which, contrary to standard receptive field models of auditory cortex function, build divergent representations of sounds with similar spectral content, but different temporal structure.

Topographical functional connectivity patterns exist in the congenitally, prelingually deaf.

Congenital deafness causes large changes in the auditory cortex structure and function, such that without early childhood cochlear-implant, profoundly deaf children do not develop intact, high-level, auditory functions. But how is auditory cortex organization affected by congenital, prelingual, and long standing deafness? Does the large-scale topographical organization of the auditory cortex develop in people deaf from birth? And is it retained despite cross-modal plasticity? We identified, using fMRI, topographic tonotopy-based functional connectivity (FC) structure in humans in the core auditory cortex, its extending tonotopic gradients in the belt and even beyond that. These regions show similar FC structure in the congenitally deaf throughout the auditory cortex, including in the language areas. The topographic FC pattern can be identified reliably in the vast majority of the deaf, at the single subject level, despite the absence of hearing-aid use and poor oral language skills. These findings suggest that large-scale tonotopic-based FC does not require sensory experience to develop, and is retained despite life-long auditory deprivation and cross-modal plasticity. Furthermore, as the topographic FC is retained to varying degrees among the deaf subjects, it may serve to predict the potential for auditory rehabilitation using cochlear implants in individual subjects.

Music-based rehabilitation in cochlear implant users: Insights from brain-plasticity research

Music-based rehabilitation in cochlear implant users: Insights from brain-plasticity research

From Hearing Sounds to Recognizing Phonemes: Primary Auditory Cortex is A Truly Perceptual Language Area

The aim of this article is to present a systematic review about the anatomy, function, connectivity, and functional activation of the primary auditory cortex (PAC) (Brodmann areas 41/42) when involved in language paradigms. PAC activates with a plethora of diverse basic stimuli including but not limited to tones, chords, natural sounds, consonants, and speech. Nonetheless, the PAC shows specific sensitivity to speech. Damage in the PAC is associated with so-called “pure word-deafness” (“auditory verbal agnosia”). BA41, and to a lesser extent BA42, are involved in early stages of phonological processing (phoneme recognition). Phonological processing may take place in either the right or left side, but customarily the left exerts an inhibitory tone over the right, gaining dominance in function. BA41/42 are primary auditory cortices harboring complex phoneme perception functions with asymmetrical expression, making it possible to include them as core language processing areas (Wernicke’s area).

The cat's meow: A high-field fMRI assessment of cortical activity in response to vocalizations and complex auditory stimuli

Sensory systems are typically constructed in a hierarchical fashion such that lower level subcortical and cortical areas process basic stimulus features, while higher level areas reassemble these features into object-level representations. A number of anatomical pathway tracing studies have suggested that the auditory cortical hierarchy of the cat extends from a core region, consisting of the primary auditory cortex (A1) and the anterior auditory field (AAF), to higher level auditory fields that are located ventrally. Unfortunately, limitations on electrophysiological examination of these higher level fields have resulted in an incomplete understanding of the functional organization of the auditory cortex. Thus, the current study uses functional MRI in conjunction with a variety of simple and complex auditory stimuli to provide the first comprehensive examination of function across the entire cortical hierarchy. Auditory cortex function is shown to be largely lateralized to the left hemisphere, and is concentrated bilaterally in fields surrounding the posterior ectosylvian sulcus. The use of narrowband noise stimuli enables the visualization of tonotopic gradients in the posterior auditory field (PAF) and ventral posterior auditory field (VPAF) that have previously been unverifiable using fMRI and pure tones. Furthermore, auditory fields that are inaccessible to more invasive techniques, such as the insular (IN) and temporal (T) cortices, are shown to be selectively responsive to vocalizations. Collectively, these data provide a much needed functional correlate for anatomical examinations of the hierarchy of cortical structures within the cat auditory cortex.

What is the function of auditory cortex without auditory input?

This scientific commentary refers to ‘Cross-modal activation of auditory regions during visuo-spatial working memory in early deafness’, by Ding et al. (doi:10.1093/brain/awv165). When a sensory input is absent during development, regions of the brain usually dedicated to processing input from that modality can be engaged to process input from a replacement sense. This is referred to as cross-modal plasticity, and studying it can provide rich and unique insights into the biological versus environmental constraints that act on brain development and brain function (Merabet and Pascal-Leone, 2010). For example, numerous studies report greater activation of typically ‘auditory association cortices’ in the superior temporal gyrus (STG), sulcus and planum temporale, in those born profoundly deaf than in their hearing peers when processing visual or somatosensory input (e.g. Karns et al. , 2012). There is also a wealth of research reporting enhanced behavioural performance on visuo-spatial tasks in deaf versus hearing participants (Bavelier et al. , 2006). Although it is tempting to make the intuitive assumption that these two findings must be linked, no studies with humans have yet demonstrated a clear link between the extent of cross-modal plasticity in auditory cortices in those born deaf and enhanced performance on visuo-spatial tasks. This is the question addressed by Ding and co-workers in this issue of Brain (2015). In their study, Ding e t al . asked hearing and congenitally deaf participants to perform a visuo-spatial working memory task while functional MRI data were collected. Deaf participants showed faster responses than hearing participants, although there was no group difference in task accuracy. In support of previous studies, Ding et al. report evidence of cross-modal plasticity (greater activation in deaf than hearing participants) in auditory …

Developmental Trajectories of Auditory Cortex Synaptic Structures and Gap-Prepulse Inhibition of Acoustic Startle Between Early Adolescence and Young Adulthood in Mice.

Cortical excitatory and inhibitory synapses are disrupted in schizophrenia, the symptoms of which often emerge during adolescence, when cortical excitatory synapses undergo pruning. In auditory cortex, a brain region implicated in schizophrenia, little is known about the development of excitatory and inhibitory synapses between early adolescence and young adulthood, and how these changes impact auditory cortex function. We used immunohistochemistry and quantitative fluorescence microscopy to quantify dendritic spines and GAD65-expressing inhibitory boutons in auditory cortex of early adolescent, late adolescent, and young adult mice. Numbers of spines decreased between early adolescence and young adulthood, during which time responses increased in an auditory cortex-dependent sensory task, silent gap-prepulse inhibition of the acoustic startle reflex (gap-PPI). Within-bouton GAD65 protein and GAD65-expressing bouton numbers decreased between late adolescence and young adulthood, a delay in onset relative to spine and gap-PPI changes. In mice lacking the spine protein kalirin, there were no significant changes in spine number, within-bouton GAD65 protein, or gap-PPI between adolescence and young adulthood. These results illustrate developmental changes in auditory cortex spines, inhibitory boutons, and auditory cortex function between adolescence and young adulthood, and provide insights into how disrupted adolescent neurodevelopment could contribute to auditory cortex synapse pathology and auditory impairments.

Cochlear implantation (CI) for prelingual deafness: the relevance of studies of brain organization and the role of first language acquisition in considering outcome success.

Cochlear implantation (CI) for profound congenital hearing impairment, while often successful in restoring hearing to the deaf child, does not always result in effective speech processing. Exposure to non-auditory signals during the pre-implantation period is widely held to be responsible for such failures. Here, we question the inference that such exposure irreparably distorts the function of auditory cortex, negatively impacting the efficacy of CI. Animal studies suggest that in congenital early deafness there is a disconnection between (disordered) activation in primary auditory cortex (A1) and activation in secondary auditory cortex (A2). In humans, one factor contributing to this functional decoupling is assumed to be abnormal activation of A1 by visual projections—including exposure to sign language. In this paper we show that that this abnormal activation of A1 does not routinely occur, while A2 functions effectively supramodally and multimodally to deliver spoken language irrespective of hearing status. What, then, is responsible for poor outcomes for some individuals with CI and for apparent abnormalities in cortical organization in these people? Since infancy is a critical period for the acquisition of language, deaf children born to hearing parents are at risk of developing inefficient neural structures to support skilled language processing. A sign language, acquired by a deaf child as a first language in a signing environment, is cortically organized like a heard spoken language in terms of specialization of the dominant perisylvian system. However, very few deaf children are exposed to sign language in early infancy. Moreover, no studies to date have examined sign language proficiency in relation to cortical organization in individuals with CI. Given the paucity of such relevant findings, we suggest that the best guarantee of good language outcome after CI is the establishment of a secure first language pre-implant—however that may be achieved, and whatever the success of auditory restoration.

Functional evaluation of auditory cortex by functional magnetic resonance before cochlear implantation: a pilot study

To investigate the functional evaluation of auditory cortex by functional magnetic resonance imaging (fMRI) before cochlear implantation (CI). Twenty-one children with severe to profound sensorineural hearing loss (SNHL) (7 cases with normal inner ear structure, 3 cases with large vestibular aqueduct syndrome, 1 case with cochlear nerve hypoplasia) and 7 children with normal hearing were examined by fMRI under sedation. The subjects received acoustic stimuli at four random frequencies (500, 1 000, 2 000, 4 000 Hz) during fMRI examination. Tones were interleaved with silence in a block-periodic fMRI design with 16-second on-off intervals.Each stimulus repeated twice and the total acquisition time was 4 minutes and 28 seconds. Activation was identified in the auditory cortex of the 28 subjects in response to monaural and binaural acoustic stimulation, which was shown in the transverse temporal gyrus (Heschl gyrus), the thalamus and both.Of the 21 patients with SNHL, contralateral dominance was shown in six cases, ipsilateral dominance in five cases and bilateral equilibrium in 10 cases when one ear was exposed to the stimuli. Of the seven children with normal hearing, contralateral dominance was shown in three cases, ipsilateral dominance in two cases and bilateral equilibrium in two cases.No significant difference of the activation intensity in auditory cortex was shown between children with SNHL and normal hearing (P > 0.05). Good hearing recovery was obtained in the 21 patients after CI. No significant difference in the level of hearing and speech rehabilitation was shown between children with LVAS and with normal inner ear structure.Listening behavior response threshold was 55 dBHL in the case with cochlear nerve hypoplasia 10 months after CI. fMRI would be a feasible means of evaluating the function of the auditory cortex, which can be used for assessing the function of the entire auditory system prior to CI combined with ABR and imaging.

Quantitative analysis of neuronal response properties in primary and higher-order auditory cortical fields of awake house mice (Mus musculus).

Because of its great genetic potential, the mouse (Mus musculus) has become a popular model species for studies on hearing and sound processing along the auditory pathways. Here, we present the first comparative study on the representation of neuronal response parameters to tones in primary and higher-order auditory cortical fields of awake mice. We quantified 12 neuronal properties of tone processing in order to estimate similarities and differences of function between the fields, and to discuss how far auditory cortex (AC) function in the mouse is comparable to that in awake monkeys and cats. Extracellular recordings were made from 1400 small clusters of neurons from cortical layers III/IV in the primary fields AI (primary auditory field) and AAF (anterior auditory field), and the higher-order fields AII (second auditory field) and DP (dorsoposterior field). Field specificity was shown with regard to spontaneous activity, correlation between spontaneous and evoked activity, tone response latency, sharpness of frequency tuning, temporal response patterns (occurrence of phasic responses, phasic-tonic responses, tonic responses, and off-responses), and degree of variation between the characteristic frequency (CF) and the best frequency (BF) (CF–BF relationship). Field similarities were noted as significant correlations between CFs and BFs, V-shaped frequency tuning curves, similar minimum response thresholds and non-monotonic rate-level functions in approximately two-thirds of the neurons. Comparative and quantitative analyses showed that the measured response characteristics were, to various degrees, susceptible to influences of anesthetics. Therefore, studies of neuronal responses in the awake AC are important in order to establish adequate relationships between neuronal data and auditory perception and acoustic response behavior.

Atypical brain lateralisation in the auditory cortex and language performance in 3- to 7-year-old children with high-functioning autism spectrum disorder: a child-customised magnetoencephalography (MEG) study

BackgroundMagnetoencephalography (MEG) is used to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. In young children, however, the simultaneous quantification of the bilateral auditory-evoked response during binaural hearing is difficult using conventional adult-sized MEG systems. Recently, a child-customised MEG device has facilitated the acquisition of bi-hemispheric recordings, even in young children. Using the child-customised MEG device, we previously reported that language-related performance was reflected in the strength of the early component (P50m) of the auditory evoked magnetic field (AEF) in typically developing (TD) young children (2 to 5 years old) [Eur J Neurosci 2012, 35:644–650]. The aim of this study was to investigate how this neurophysiological index in each hemisphere is correlated with language performance in autism spectrum disorder (ASD) and TD children.MethodsWe used magnetoencephalography (MEG) to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. We investigated the P50m that is evoked by voice stimuli (/ne/) bilaterally in 33 young children (3 to 7 years old) with ASD and in 30 young children who were typically developing (TD). The children were matched according to their age (in months) and gender. Most of the children with ASD were high-functioning subjects.ResultsThe results showed that the children with ASD exhibited significantly less leftward lateralisation in their P50m intensity compared with the TD children. Furthermore, the results of a multiple regression analysis indicated that a shorter P50m latency in both hemispheres was specifically correlated with higher language-related performance in the TD children, whereas this latency was not correlated with non-verbal cognitive performance or chronological age. The children with ASD did not show any correlation between P50m latency and language-related performance; instead, increasing chronological age was a significant predictor of shorter P50m latency in the right hemisphere.ConclusionsUsing a child-customised MEG device, we studied the P50m component that was evoked through binaural human voice stimuli in young ASD and TD children to examine differences in auditory cortex function that are associated with language development. Our results suggest that there is atypical brain function in the auditory cortex in young children with ASD, regardless of language development.

Maturational differences in thalamocortical white matter microstructure and auditory evoked response latencies in autism spectrum disorders

White matter diffusion anisotropy in the acoustic radiations was characterized as a function of development in autistic and typically developing children. Auditory-evoked neuromagnetic fields were also recorded from the same individuals and the latency of the left and right middle latency superior temporal gyrus auditory ~50ms response (M50)11M50: superior temporal gyrus auditory 50ms response; FA: fractional anisotropy; WM: white matter; MEG: magnetoencephalography; DTI: diffusion tensor imaging; ASD: autism spectrum disorder; TD: typically developing. was measured. Group differences in structural and functional auditory measures were examined, as were group differences in associations between white matter pathways, M50 latency, and age. Acoustic radiation white matter fractional anisotropy did not differ between groups. Individuals with autism displayed a significant M50 latency delay. Only in typically developing controls, white matter fractional anisotropy increased with age and increased white matter anisotropy was associated with earlier M50 responses. M50 latency, however, decreased with age in both groups. Present findings thus indicate that although there is loss of a relationship between white matter structure and auditory cortex function in autism spectrum disorders, and although there are delayed auditory responses in individuals with autism than compared with age-matched controls, M50 latency nevertheless decreases as a function of age in autism, parallel to the observation in typically developing controls (although with an overall latency delay). To understand auditory latency delays in autism and changes in auditory responses as a function of age in controls and autism, studies examining white matter as well as other factors that influence auditory latency, such as synaptic transmission, are of interest.

On the planum temporale lateralization in suprasegmental speech perception: Evidence from a study investigating behavior, structure, and function

This study combines functional and structural magnetic resonance imaging to test the "asymmetric sampling in time" (AST) hypothesis, which makes assertions about the symmetrical and asymmetrical representation of speech in the primary and nonprimary auditory cortex. Twenty-three volunteers participated in this parametric clustered-sparse fMRI study. The availability of slowly changing acoustic cues in spoken sentences was systematically reduced over continuous segments with varying lengths (100, 150, 200, 250 ms) by utilizing local time-reversion. As predicted by the hypothesis, functional lateralization in Heschl's gyrus could not be observed. Lateralization in the planum temporale and posterior superior temporal gyrus shifted towards the right hemisphere with decreasing suprasegmental temporal integrity. Cortical thickness of the planum temporale was automatically measured. Participants with an L > R cortical thickness performed better on the in-scanner auditory pattern-matching task. Taken together, these findings support the AST hypothesis and provide substantial novel insight into the division of labor between left and right nonprimary auditory cortex functions during comprehension of spoken utterances. In addition, the present data yield support for a structural-behavioral relationship in the nonprimary auditory cortex.

Increased Volume and Function of Right Auditory Cortex as a Marker for Absolute Pitch

Absolute pitch (AP) perception is the auditory ability to effortlessly recognize the pitch of any given tone without external reference. To study the neural substrates of this rare phenomenon, we developed a novel behavioral test, which excludes memory-based interval recognition and permits quantification of AP proficiency independently of relative pitch cues. AP- and non-AP-possessing musicians were studied with morphological and functional magnetic resonance imaging (fMRI) and magnetoencephalography. Gray matter volume of the right Heschl's gyrus (HG) was highly correlated with AP proficiency. Right-hemispheric auditory evoked fields were increased in the AP group. fMRI revealed an AP-dependent network of right planum temporale, secondary somatosensory, and premotor cortices, as well as left-hemispheric "Broca's" area. We propose the right HG as an anatomical marker of AP and suggest that a right-hemispheric network mediates AP "perception," whereas pitch "labeling" takes place in the left hemisphere.

Rapid plasticity in auditory and prefrontal cortex during active listening

Humans and other animals often attend to sounds in their environment so as to approach mates and competitors, or to avoid predators. Numerous neural processes orchestrate the performance of these behavioral tasks, including sensory adaptive responses in the auditory cortex and executive control functions in the prefrontal cortex. The multitude of mechanisms observed to be involved in neurophysiological recordings from several auditory and prefrontal cortical fields in behaving ferrets will be reviewed. The findings reveal that rapid changes in auditory receptive fields take place only during task performance, and that these serve to enhance discrimination and detection of target stimuli from their backgrounds. Interestingly, the changes also depend on the meaning of the sounds (aversive or appetitive) and the level of behavioral performance.

Plasticity in the Primary Auditory Cortex, Not What You Think it is: Implications for Basic and Clinical Auditory Neuroscience

Standard beliefs that the function of the primary auditory cortex (A1) is the analysis of sound have proven to be incorrect. Its involvement in learning, memory and other complex processes in both animals and humans is now well-established, although often not appreciated. Auditory coding is strongly modifed by associative learning, evident as associative representational plasticity (ARP) in which the representation of an acoustic dimension, like frequency, is re-organized to emphasize a sound that has become behaviorally important. For example, the frequency tuning of a cortical neuron can be shifted to match that of a significant sound and the representational area of sounds that acquire behavioral importance can be increased. ARP depends on the learning strategy used to solve an auditory problem and the increased cortical area confers greater strength of auditory memory. Thus, primary auditory cortex is involved in cognitive processes, transcending its assumed function of auditory stimulus analysis. The implications for basic neuroscience and clinical auditory neuroscience are presented and suggestions for remediation of auditory processing disorders are introduced.