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Clinical Neurophysiology : Official... Oct 2018This study investigated the function and networks of the auditory cortices in the posterior lateral superior temporal area (PLST) using a combination of electrical...
OBJECTIVE
This study investigated the function and networks of the auditory cortices in the posterior lateral superior temporal area (PLST) using a combination of electrical cortical stimulation and diffusion tensor imaging (DTI).
METHODS
Seven patients with intractable focal epilepsy in which the PLST auditory cortices were identified during the electrical cortical stimulation were enrolled in this study (left side: four patients, right side: three patients). Electrical stimulation at 50 Hz was applied to the chronically implanted subdural electrodes to identify the PLST auditory cortices. DTI was used to identify the subcortical fibers originating from the PLST auditory cortices found by electrical stimulation.
RESULTS
Electrical stimulation of the right PLST auditory cortices induced hearing impairment in three patients and left side stimulation elicited hearing illusory sounds in four patients. DTI detected the middle longitudinal fasciculus (MLF) in all patients, the superior longitudinal fasciculus (SLF) in six patients and the inferior fronto-occipital fasciculus (IFOF) in three patients, originating from the PLST auditory cortices.
CONCLUSION
This study suggests different functional roles between the right and left PLST auditory cortices, and the networks originating from these areas.
SIGNIFICANCE
MLF, SLF and IFOF might be associated with the auditory processing.
Topics: Adolescent; Adult; Auditory Cortex; Auditory Pathways; Auditory Perception; Brain Mapping; Deep Brain Stimulation; Diffusion Tensor Imaging; Epilepsies, Partial; Evoked Potentials, Auditory; Female; Functional Laterality; Humans; Male; Middle Aged
PubMed: 30110660
DOI: 10.1016/j.clinph.2018.07.014 -
The Journal of Neuroscience : the... Apr 2019Absolute pitch (AP), the ability of some musicians to precisely identify and name musical tones in isolation, is associated with a number of gross morphological changes...
Absolute pitch (AP), the ability of some musicians to precisely identify and name musical tones in isolation, is associated with a number of gross morphological changes in the brain, but the fundamental neural mechanisms underlying this ability have not been clear. We presented a series of logarithmic frequency sweeps to age- and sex-matched groups of musicians with or without AP and controls without musical training. We used fMRI and population receptive field (pRF) modeling to measure the responses in the auditory cortex in 61 human subjects. The tuning response of each fMRI voxel was characterized as Gaussian, with independent center frequency and bandwidth parameters. We identified three distinct tonotopic maps, corresponding to primary (A1), rostral (R), and rostral-temporal (RT) regions of auditory cortex. We initially hypothesized that AP abilities might manifest in sharper tuning in the auditory cortex. However, we observed that AP subjects had larger cortical area, with the increased area primarily devoted to broader frequency tuning. We observed anatomically that A1, R and RT were significantly larger in AP musicians than in non-AP musicians or control subjects, which did not differ significantly from each other. The increased cortical area in AP in areas A1 and R were primarily low frequency and broadly tuned, whereas the distribution of responses in area RT did not differ significantly. We conclude that AP abilities are associated with increased early auditory cortical area devoted to broad-frequency tuning and likely exploit increased ensemble encoding. Absolute pitch (AP), the ability of some musicians to precisely identify and name musical tones in isolation, is associated with a number of gross morphological changes in the brain, but the fundamental neural mechanisms have not been clear. Our study shows that AP musicians have significantly larger volume in early auditory cortex than non-AP musicians and non-musician controls and that this increased volume is primarily devoted to broad-frequency tuning. We conclude that AP musicians are likely able to exploit increased ensemble representations to encode and identify frequency.
Topics: Acoustic Stimulation; Adult; Auditory Cortex; Auditory Perception; Female; Humans; Magnetic Resonance Imaging; Male; Music; Pitch Discrimination; Pitch Perception; Psychomotor Performance; Young Adult
PubMed: 30745420
DOI: 10.1523/JNEUROSCI.1532-18.2019 -
Annual Review of Neuroscience Jul 2018How the cerebral cortex encodes auditory features of biologically important sounds, including speech and music, is one of the most important questions in auditory... (Review)
Review
How the cerebral cortex encodes auditory features of biologically important sounds, including speech and music, is one of the most important questions in auditory neuroscience. The pursuit to understand related neural coding mechanisms in the mammalian auditory cortex can be traced back several decades to the early exploration of the cerebral cortex. Significant progress in this field has been made in the past two decades with new technical and conceptual advances. This article reviews the progress and challenges in this area of research.
Topics: Animals; Auditory Cortex; Auditory Pathways; Auditory Perception; Brain Mapping; Hearing; Humans; Music; Speech
PubMed: 29986161
DOI: 10.1146/annurev-neuro-072116-031302 -
Neuroscience 2004We examined efferent connections of the cortical auditory field that receives thalamic afferents specifically from the suprageniculate nucleus (SG) and the dorsal...
We examined efferent connections of the cortical auditory field that receives thalamic afferents specifically from the suprageniculate nucleus (SG) and the dorsal division (MGD) of the medial geniculate body (MG) in the rat [Neuroscience 117 (2003) 1003]. The examined cortical region was adjacent to the caudodorsal border (4.8-7.0 mm posterior to bregma) of the primary auditory area (area Te1) and exhibited relatively late auditory response and high best frequency, compared with the caudal end of area Te1. On the basis of the location and auditory response property, the cortical region is considered identical to "posterodorsal" auditory area (PD). Injections of biocytin in PD revealed characteristic projections, which terminated in cortical areas and subcortical structures that play pivotal roles in directed attention and space processing. The most noticeable cortical terminal field appeared as dense plexuses of axons in area Oc2M, the posterior parietal cortex. Small terminal fields were scattered in area frontal cortex, area 2 that comprises the frontal eye field. The subcortical terminal fields were observed in the pontine nucleus, the nucleus of the brachium inferior colliculus, and the intermediate and deep layers of the superior colliculus. Corticostriatal projections targeted two discrete regions of the caudate putamen: the top of the middle part and the caudal end. It is noteworthy that the inferior colliculus and amygdala virtually received no projection. Corticothalamic projections terminated in the MGD, the SG, the ventral zone of the ventral division of the MG, the ventral margin of the lateral posterior nucleus (LP), and the caudodorsal part of the posterior thalamic nuclear group (Po). Large terminals were found in the MGD, SG, LP and Po besides small terminals, the major component of labeling. The results suggest that PD is an auditory area that plays an important role in spatial processing linked to directed attention and motor function. The results extend to the rat findings from nonhuman primates suggesting the existence of a posterodorsal processing stream for auditory spatial perception.
Topics: Acoustic Stimulation; Animals; Attention; Auditory Cortex; Auditory Pathways; Brain Mapping; Efferent Pathways; Lysine; Parietal Lobe; Rats; Rats, Wistar; Sound Localization; Superior Colliculi; Synaptic Transmission; Thalamic Nuclei; Visual Fields
PubMed: 15350651
DOI: 10.1016/j.neuroscience.2004.07.010 -
Proceedings of the National Academy of... May 2019Previous studies report that human middle temporal complex (hMT+) is sensitive to auditory motion in early-blind individuals. Here, we show that hMT+ also develops...
Previous studies report that human middle temporal complex (hMT+) is sensitive to auditory motion in early-blind individuals. Here, we show that hMT+ also develops selectivity for auditory frequency after early blindness, and that this selectivity is maintained after sight recovery in adulthood. Frequency selectivity was assessed using both moving band-pass and stationary pure-tone stimuli. As expected, within primary auditory cortex, both moving and stationary stimuli successfully elicited frequency-selective responses, organized in a tonotopic map, for all subjects. In early-blind and sight-recovery subjects, we saw evidence for frequency selectivity within hMT+ for the auditory stimulus that contained motion. We did not find frequency-tuned responses within hMT+ when using the stationary stimulus in either early-blind or sight-recovery subjects. We saw no evidence for auditory frequency selectivity in hMT+ in sighted subjects using either stimulus. Thus, after early blindness, hMT+ can exhibit selectivity for auditory frequency. Remarkably, this auditory frequency tuning persists in two adult sight-recovery subjects, showing that, in these subjects, auditory frequency-tuned responses can coexist with visually driven responses in hMT+.
Topics: Adult; Auditory Cortex; Auditory Perception; Blindness; Case-Control Studies; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Motion Perception; Occipital Lobe
PubMed: 31036666
DOI: 10.1073/pnas.1815376116 -
Neuroscience Sep 2006The rat auditory cortex is made up of multiple auditory fields. A precise correlation between anatomical and physiological areal extents of auditory fields, however, is... (Comparative Study)
Comparative Study
The rat auditory cortex is made up of multiple auditory fields. A precise correlation between anatomical and physiological areal extents of auditory fields, however, is not yet fully established, mainly because non-primary auditory fields remain undetermined. In the present study, based on thalamocortical connection, electrical stimulation and auditory response, we delineated a non-primary auditory field in the cortical region ventral to the primary auditory area and anterior auditory field. We designated it as "ventral" area after its relative location. At first, based on anterograde labeling of thalamocortical projection with biocytin, ventral auditory area was delineated as a main cortical terminal field of thalamic afferents that arise from the dorsal division of the medial geniculate body. Cortical terminal field (ventral auditory area) extended into the ventral margin of temporal cortex area 1 (Te1) and the dorsal part of temporal cortex area 3, ventral (Te3V), from 3.2-4.6 mm posterior to bregma. Electrical stimulation of the dorsal division of the medial geniculate body; evoked epicortical field potentials confined to the comparable cortical region. On the basis of epicortical field potentials evoked by pure tones, best frequencies were further estimated at and around the cortical region where electrical stimulation of the dorsal division of the medial geniculate body evoked field potentials. Ventral auditory area was found to represent frequencies primarily below 15 kHz, which contrasts with our previous finding that the posterodorsal area, the other major recipient of the dorsal division of the medial geniculate body; projection, represents primarily high frequencies (>15 kHz). The posterodorsal area is thought to play a pivotal role in auditory spatial processing [Kimura A, Donishi T, Okamoto K, Tamai Y (2004) Efferent connections of "posterodorsal" auditory area in the rat cortex: implications for auditory spatial processing. Neuroscience 128:399-419]. The ventral auditory area, as the other main cortical region that would relay auditory input from the dorsal division of the medial geniculate body to higher cortical information processing, could serve an important extralemniscal function in tandem with the posterodorsal area. The results provide insight into structural and functional organization of the rat auditory cortex.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Pathways; Brain Mapping; Dose-Response Relationship, Radiation; Electric Stimulation; Evoked Potentials, Auditory; Geniculate Bodies; Lysine; Rats; Rats, Wistar
PubMed: 16750887
DOI: 10.1016/j.neuroscience.2006.04.037 -
Neuroscience Sep 2014The neural pathways of the auditory system underlie our ability to detect sounds and to transform amplitude and frequency information into rich and meaningful... (Review)
Review
The neural pathways of the auditory system underlie our ability to detect sounds and to transform amplitude and frequency information into rich and meaningful perception. While it shares some organizational features with other sensory systems, the auditory system has some unique functions that impose special demands on precision in circuit assembly. In particular, the cochlear epithelium creates a frequency map rather than a space map, and specialized pathways extract information on interaural time and intensity differences to permit sound source localization. The assembly of auditory circuitry requires the coordinated function of multiple molecular cues. Eph receptors and their ephrin ligands constitute a large family of axon guidance molecules with developmentally regulated expression throughout the auditory system. Functional studies of Eph/ephrin signaling have revealed important roles at multiple levels of the auditory pathway, from the cochlea to the auditory cortex. These proteins provide graded cues used in establishing tonotopically ordered connections between auditory areas, as well as discrete cues that enable axons to form connections with appropriate postsynaptic partners within a target area. Throughout the auditory system, Eph proteins help to establish patterning in neural pathways during early development. This early targeting, which is further refined with neuronal activity, establishes the precision needed for auditory perception.
Topics: Animals; Auditory Cortex; Auditory Pathways; Axons; Brain Stem; Cochlea; Ephrins; Receptors, Eph Family
PubMed: 25010398
DOI: 10.1016/j.neuroscience.2014.06.068 -
Acta Neurochirurgica. Supplement 2007Functional imaging techniques have demonstrated a relationship between the intensity of tinnitus and the degree of reorganization of the primary auditory cortex. Studies... (Review)
Review
Functional imaging techniques have demonstrated a relationship between the intensity of tinnitus and the degree of reorganization of the primary auditory cortex. Studies in experimental animals and humans have revealed that tinnitus is associated with a synchronized hyperactivity in the auditory cortex and proposed that the underlying pathophysiological mechanism is thalamocortical dysrhythmia; hence, decreased auditory stimulation results in decreased firing rate, and decreased lateral inhibition. Consequently, the surrounding brain area becomes hyperactive, firing at gamma band rates; this is considered a necessary precondition of auditory consciousness, and also tinnitus. Synchronization of the gamma band activity could possibly induce a topographical reorganization based on Hebbian mechanisms. Therefore, it seems logical to try to suppress tinnitus by modifying the tinnitus-related auditory cortex reorganization and hyperactivity. This can be achieved using neuronavigation-guided transcranial magnetic stimulation (TMS), which is capable of modulating cortical activity. If TMS is capable of suppressing tinnitus, the effect should be maintained by implanting electrodes over the area of electrophysiological signal abnormality on the auditory cortex. The results in the first patients treated by auditory cortex stimulation demonstrate a statistically significant tinnitus suppression in cases of unilateral pure tone tinnitus without suppression of white or narrow band noise. Hence, auditory cortex stimulation could become a physiologically guided treatment for a selected category of patients with severe tinnitus.
Topics: Animals; Auditory Cortex; Brain Mapping; Electric Stimulation Therapy; Functional Laterality; Humans; Magnetic Resonance Imaging; Neuronavigation; Tinnitus; Transcranial Magnetic Stimulation
PubMed: 17691335
DOI: 10.1007/978-3-211-33081-4_52 -
Schizophrenia Bulletin Jan 2017Neuroimaging studies have demonstrated associations between smaller auditory cortex volume and auditory hallucinations (AH) in schizophrenia. Reduced cortical volume can...
BACKGROUND
Neuroimaging studies have demonstrated associations between smaller auditory cortex volume and auditory hallucinations (AH) in schizophrenia. Reduced cortical volume can result from a reduction of either cortical thickness or cortical surface area, which may reflect different neuropathology. We investigate for the first time how thickness and surface area of the auditory cortex relate to AH in a large sample of schizophrenia spectrum patients.
METHODS
Schizophrenia spectrum (n = 194) patients underwent magnetic resonance imaging. Mean cortical thickness and surface area in auditory cortex regions (Heschl's gyrus [HG], planum temporale [PT], and superior temporal gyrus [STG]) were compared between patients with (AH+, n = 145) and without (AH-, n = 49) a lifetime history of AH and 279 healthy controls.
RESULTS
AH+ patients showed significantly thinner cortex in the left HG compared to AH- patients (d = 0.43, P = .0096). There were no significant differences between AH+ and AH- patients in cortical thickness in the PT or STG, or in auditory cortex surface area in any of the regions investigated. Group differences in cortical thickness in the left HG was not affected by duration of illness or current antipsychotic medication.
CONCLUSIONS
AH in schizophrenia patients were related to thinner cortex, but not smaller surface area of the left HG, a region which includes the primary auditory cortex. The results support that structural abnormalities of the auditory cortex underlie AH in schizophrenia.
Topics: Adult; Auditory Cortex; Auditory Perception; Female; Hallucinations; Humans; Magnetic Resonance Imaging; Male; Psychotic Disorders; Schizophrenia; Young Adult
PubMed: 27605526
DOI: 10.1093/schbul/sbw130 -
Brain Research. Brain Research Reviews Dec 2003In the present review, we summarize the most recent findings and current views about the structural and functional basis of human brain lateralization in the auditory... (Review)
Review
In the present review, we summarize the most recent findings and current views about the structural and functional basis of human brain lateralization in the auditory modality. Main emphasis is given to hemodynamic and electromagnetic data of healthy adult participants with regard to music- vs. speech-sound encoding. Moreover, a selective set of behavioral dichotic-listening (DL) results and clinical findings (e.g., schizophrenia, dyslexia) are included. It is shown that human brain has a strong predisposition to process speech sounds in the left and music sounds in the right auditory cortex in the temporal lobe. Up to great extent, an auditory area located at the posterior end of the temporal lobe (called planum temporale [PT]) underlies this functional asymmetry. However, the predisposition is not bound to informational sound content but to rapid temporal information more common in speech than in music sounds. Finally, we obtain evidence for the vulnerability of the functional specialization of sound processing. These altered forms of lateralization may be caused by top-down and bottom-up effects inter- and intraindividually In other words, relatively small changes in acoustic sound features or in their familiarity may modify the degree in which the left vs. right auditory areas contribute to sound encoding.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Brain Mapping; Functional Laterality; Humans
PubMed: 14629926
DOI: 10.1016/j.brainresrev.2003.08.004