Auditory Pathways: NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.Inferior Colliculi: The posterior pair of the quadrigeminal bodies which contain centers for auditory function.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Auditory Diseases, Central: Disorders of hearing or auditory perception due to pathological processes of the AUDITORY PATHWAYS in the CENTRAL NERVOUS SYSTEM. These include CENTRAL HEARING LOSS and AUDITORY PERCEPTUAL DISORDERS.Evoked Potentials, Auditory, Brain Stem: Electrical waves in the CEREBRAL CORTEX generated by BRAIN STEM structures in response to auditory click stimuli. These are found to be abnormal in many patients with CEREBELLOPONTINE ANGLE lesions, MULTIPLE SCLEROSIS, or other DEMYELINATING DISEASES.Cochlear Nucleus: The brain stem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organized, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.Cochlear Nerve: The cochlear part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The cochlear nerve fibers originate from neurons of the SPIRAL GANGLION and project peripherally to cochlear hair cells and centrally to the cochlear nuclei (COCHLEAR NUCLEUS) of the BRAIN STEM. They mediate the sense of hearing.Evoked Potentials, Auditory: The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.Auditory Cortex: The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.Olivary Nucleus: A part of the MEDULLA OBLONGATA situated in the olivary body. It is involved with motor control and is a major source of sensory input to the CEREBELLUM.Vestibulocochlear Nerve: The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (COCHLEAR NERVE) which is concerned with hearing and a vestibular part (VESTIBULAR NERVE) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the SPIRAL GANGLION and project to the cochlear nuclei (COCHLEAR NUCLEUS). The fibers of the vestibular nerve arise from neurons of Scarpa's ganglion and project to the VESTIBULAR NUCLEI.Auditory Perceptual Disorders: Acquired or developmental cognitive disorders of AUDITORY PERCEPTION characterized by a reduced ability to perceive information contained in auditory stimuli despite intact auditory pathways. Affected individuals have difficulty with speech perception, sound localization, and comprehending the meaning of inflections of speech.Auditory Threshold: The audibility limit of discriminating sound intensity and pitch.Tinnitus: A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.Sound Localization: Ability to determine the specific location of a sound source.Hearing: The ability or act of sensing and transducing ACOUSTIC STIMULATION to the CENTRAL NERVOUS SYSTEM. It is also called audition.Ear: The hearing and equilibrium system of the body. It consists of three parts: the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR. Sound waves are transmitted through this organ where vibration is transduced to nerve signals that pass through the ACOUSTIC NERVE to the CENTRAL NERVOUS SYSTEM. The inner ear also contains the vestibular organ that maintains equilibrium by transducing signals to the VESTIBULAR NERVE.Brain Stem: The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.Reflex, Acoustic: Intra-aural contraction of tensor tympani and stapedius in response to sound.Geniculate Bodies: Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.Cochlea: The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.Deafness: A general term for the complete loss of the ability to hear from both ears.Audiometry, Evoked Response: A form of electrophysiologic audiometry in which an analog computer is included in the circuit to average out ongoing or spontaneous brain wave activity. A characteristic pattern of response to a sound stimulus may then become evident. Evoked response audiometry is known also as electric response audiometry.Noise: Any sound which is unwanted or interferes with HEARING other sounds.Sound: A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.Pitch Perception: A dimension of auditory sensation varying with cycles per second of the sound stimulus.Audiometry, Pure-Tone: Measurement of hearing based on the use of pure tones of various frequencies and intensities as auditory stimuli.Cochlear Microphonic Potentials: The electric response of the cochlear hair cells to acoustic stimulation.Cochlear Implantation: Surgical insertion of an electronic hearing device (COCHLEAR IMPLANTS) with electrodes to the COCHLEAR NERVE in the inner ear to create sound sensation in patients with residual nerve fibers.Event-Related Potentials, P300: A late-appearing component of the event-related potential. P300 stands for a positive deflection in the event-related voltage potential at 300 millisecond poststimulus. Its amplitude increases with unpredictable, unlikely, or highly significant stimuli and thereby constitutes an index of mental activity. (From Campbell, Psychiatric Dictionary, 6th ed)Loudness Perception: The perceived attribute of a sound which corresponds to the physical attribute of intensity.Gryllidae: The family Gryllidae consists of the common house cricket, Acheta domesticus, which is used in neurological and physiological studies. Other genera include Gryllotalpa (mole cricket); Gryllus (field cricket); and Oecanthus (tree cricket).Reaction Time: The time from the onset of a stimulus until a response is observed.Psychoacoustics: The science pertaining to the interrelationship of psychologic phenomena and the individual's response to the physical properties of sound.Vocalization, Animal: Sounds used in animal communication.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Hearing Loss, Sensorineural: Hearing loss resulting from damage to the COCHLEA and the sensorineural elements which lie internally beyond the oval and round windows. These elements include the AUDITORY NERVE and its connections in the BRAINSTEM.Thalamus: Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.Cochlear Implants: Electronic hearing devices typically used for patients with normal outer and middle ear function, but defective inner ear function. In the COCHLEA, the hair cells (HAIR CELLS, VESTIBULAR) may be absent or damaged but there are residual nerve fibers. The device electrically stimulates the COCHLEAR NERVE to create sound sensation.Audiometry: The testing of the acuity of the sense of hearing to determine the thresholds of the lowest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 Hz are used to test air conduction thresholds and the frequencies between 250 and 4000 Hz are used to test bone conduction thresholds.Gerbillinae: A subfamily of the Muridae consisting of several genera including Gerbillus, Rhombomys, Tatera, Meriones, and Psammomys.Sound Spectrography: The graphic registration of the frequency and intensity of sounds, such as speech, infant crying, and animal vocalizations.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Speech Perception: The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).Chiroptera: Order of mammals whose members are adapted for flight. It includes bats, flying foxes, and fruit bats.Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Synapses: Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Adaptation, Physiological: The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.Synaptic Transmission: The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.Electroencephalography: Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.

The functional anatomy of the normal human auditory system: responses to 0.5 and 4.0 kHz tones at varied intensities. (1/1597)

Most functional imaging studies of the auditory system have employed complex stimuli. We used positron emission tomography to map neural responses to 0.5 and 4.0 kHz sine-wave tones presented to the right ear at 30, 50, 70 and 90 dB HL and found activation in a complex neural network of elements traditionally associated with the auditory system as well as non-traditional sites such as the posterior cingulate cortex. Cingulate activity was maximal at low stimulus intensities, suggesting that it may function as a gain control center. In the right temporal lobe, the location of the maximal response varied with the intensity, but not with the frequency of the stimuli. In the left temporal lobe, there was evidence for tonotopic organization: a site lateral to the left primary auditory cortex was activated equally by both tones while a second site in primary auditory cortex was more responsive to the higher frequency. Infratentorial activations were contralateral to the stimulated ear and included the lateral cerebellum, the lateral pontine tegmentum, the midbrain and the medial geniculate. Contrary to predictions based on cochlear membrane mechanics, at each intensity, 4.0 kHz stimuli were more potent activators of the brain than the 0.5 kHz stimuli.  (+info)

Desynchronizing responses to correlated noise: A mechanism for binaural masking level differences at the inferior colliculus. (2/1597)

We examined the adequacy of decorrelation of the responses to dichotic noise as an explanation for the binaural masking level difference (BMLD). The responses of 48 low-frequency neurons in the inferior colliculus of anesthetized guinea pigs were recorded to binaurally presented noise with various degrees of interaural correlation and to interaurally correlated noise in the presence of 500-Hz tones in either zero or pi interaural phase. In response to fully correlated noise, neurons' responses were modulated with interaural delay, showing quasiperiodic noise delay functions (NDFs) with a central peak and side peaks, separated by intervals roughly equivalent to the period of the neuron's best frequency. For noise with zero interaural correlation (independent noises presented to each ear), neurons were insensitive to the interaural delay. Their NDFs were unmodulated, with the majority showing a level of activity approximately equal to the mean of the peaks and troughs of the NDF obtained with fully correlated noise. Partial decorrelation of the noise resulted in NDFs that were, in general, intermediate between the fully correlated and fully decorrelated noise. Presenting 500-Hz tones simultaneously with fully correlated noise also had the effect of demodulating the NDFs. In the case of tones with zero interaural phase, this demodulation appeared to be a saturation process, raising the discharge at all noise delays to that at the largest peak in the NDF. In the majority of neurons, presenting the tones in pi phase had a similar effect on the NDFs to decorrelating the noise; the response was demodulated toward the mean of the peaks and troughs of the NDF. Thus the effect of added tones on the responses of delay-sensitive inferior colliculus neurons to noise could be accounted for by a desynchronizing effect. This result is entirely consistent with cross-correlation models of the BMLD. However, in some neurons, the effects of an added tone on the NDF appeared more extreme than the effect of decorrelating the noise, suggesting the possibility of additional inhibitory influences.  (+info)

Coding of sound envelopes by inhibitory rebound in neurons of the superior olivary complex in the unanesthetized rabbit. (3/1597)

Most natural sounds (e.g., speech) are complex and have amplitude envelopes that fluctuate rapidly. A number of studies have examined the neural coding of envelopes, but little attention has been paid to the superior olivary complex (SOC), a constellation of nuclei that receive information from the cochlear nucleus. We studied two classes of predominantly monaural neurons: those that displayed a sustained response to tone bursts and those that gave only a response to the tone offset. Our results demonstrate that the off neurons in the SOC can encode the pattern of amplitude-modulated sounds with high synchrony that is superior to sustained neurons. The upper cutoff frequency and highest modulation frequency at which significant synchrony was present were, on average, slightly higher for off neurons compared with sustained neurons. Finally, most sustained and off neurons encoded the level of pure tones over a wider range of intensities than those reported for auditory nerve fibers and cochlear nucleus neurons. A traditional view of inhibition is that it attenuates or terminates neural activity. Although this holds true for off neurons, the robust discharge when inhibition is released adds a new dimension. For simple sounds (i.e., pure tones), the off response can code a wide range of sound levels. For complex sounds, the off response becomes entrained to each modulation, resulting in a precise temporal coding of the envelope.  (+info)

The superior olivary nucleus and its influence on nucleus laminaris: a source of inhibitory feedback for coincidence detection in the avian auditory brainstem. (4/1597)

Located in the ventrolateral region of the avian brainstem, the superior olivary nucleus (SON) receives inputs from nucleus angularis (NA) and nucleus laminaris (NL) and projects back to NA, NL, and nucleus magnocellularis (NM). The reciprocal connections between the SON and NL are of particular interest because they constitute a feedback circuit for coincidence detection. In the present study, the chick SON was investigated. In vivo tracing studies show that the SON projects predominantly to the ipsilateral NM, NL, and NA. In vitro whole-cell recording reveals single-cell morphology, firing properties, and postsynaptic responses. SON neurons are morphologically and physiologically suited for temporal integration; their firing patterns do not reflect the temporal structure of their excitatory inputs. Of most interest, direct stimulation of the SON evokes long-lasting inhibition in NL neurons. The inhibition blocks both intrinsic spike generation and orthodromically evoked activity in NL neurons and can be eliminated by bicuculline methiodide, a potent antagonist for GABAA receptor-mediated neurotransmission. These results strongly suggest that the SON provides GABAergic inhibitory feedback to laminaris neurons. We discuss a mechanism whereby SON-evoked GABAergic inhibition can influence the coding of interaural time differences for sound localization in the avian auditory brainstem.  (+info)

Early visual experience shapes the representation of auditory space in the forebrain gaze fields of the barn owl. (5/1597)

Auditory spatial information is processed in parallel forebrain and midbrain pathways. Sensory experience early in life has been shown to exert a powerful influence on the representation of auditory space in the midbrain space-processing pathway. The goal of this study was to determine whether early experience also shapes the representation of auditory space in the forebrain. Owls were raised wearing prismatic spectacles that shifted the visual field in the horizontal plane. This manipulation altered the relationship between interaural time differences (ITDs), the principal cue used for azimuthal localization, and locations of auditory stimuli in the visual field. Extracellular recordings were used to characterize ITD tuning in the auditory archistriatum (AAr), a subdivision of the forebrain gaze fields, in normal and prism-reared owls. Prism rearing altered the representation of ITD in the AAr. In prism-reared owls, unit tuning for ITD was shifted in the adaptive direction, according to the direction of the optical displacement imposed by the spectacles. Changes in ITD tuning involved the acquisition of unit responses to adaptive ITD values and, to a lesser extent, the elimination of responses to nonadaptive (previously normal) ITD values. Shifts in ITD tuning in the AAr were similar to shifts in ITD tuning observed in the optic tectum of the same owls. This experience-based adjustment of binaural tuning in the AAr helps to maintain mutual registry between the forebrain and midbrain representations of auditory space and may help to ensure consistent behavioral responses to auditory stimuli.  (+info)

Auditory perception: does practice make perfect? (6/1597)

Recent studies have shown that adult humans can learn to localize sounds relatively accurately when provided with altered localization cues. These experiments provide further evidence for experience-dependent plasticity in the mature brain.  (+info)

Expression of type 2 iodothyronine deiodinase in hypothyroid rat brain indicates an important role of thyroid hormone in the development of specific primary sensory systems. (7/1597)

Thyroid hormone is an important epigenetic factor in brain development, acting by modulating rates of gene expression. The active form of thyroid hormone, 3,5,3'-triiodothyronine (T3) is produced in part by the thyroid gland but also after 5'-deiodination of thyroxine (T4) in target tissues. In brain, approximately 80% of T3 is formed locally from T4 through the activity of the 5'-deiodinase type 2 (D2), an enzyme that is expressed mostly by glial cells, tanycytes in the third ventricle, and astrocytes throughout the brain. D2 activity is an important point of control of thyroid hormone action because it increases in situations of low T4, thus preserving brain T3 concentrations. In this work, we have studied the expression of D2 by quantitative in situ hybridization in hypothyroid animals during postnatal development. Our hypothesis was that those regions that are most dependent on thyroid hormone should present selective increases of D2 as a protection against hypothyroidism. D2 mRNA concentration was increased severalfold over normal levels in relay nuclei and cortical targets of the primary somatosensory and auditory pathways. The results suggest that these pathways are specifically protected against thyroid failure and that T3 has a role in the development of these structures. At the cellular level, expression was observed mainly in glial cells, although some interneurons of the cerebral cortex were also labeled. Therefore, the T3 target cells, mostly neurons, are dependent on local astrocytes for T3 supply.  (+info)

Assessment of hearing in 80 inbred strains of mice by ABR threshold analyses. (8/1597)

The common occurrence of hearing loss in both humans and mice, and the anatomical and functional similarities of their inner ears, attest to the potential of mice being used as models to study inherited hearing loss. A large-scale, auditory screening project is being undertaken at The Jackson Laboratory (TJL) to identify mice with inherited hearing disorders. To assess hearing sensitivity, at least five mice from each inbred strain had auditory brainstem response (ABR) thresholds determined. Thus far, we have screened 80 inbred strains of mice; 60 of them exhibited homogeneous ABR threshold values not significantly different from those of the control strain CBA/CaJ. This large database establishes a reliable reference for normal hearing mouse strains. The following 16 inbred strains exhibited significantly elevated ABR thresholds before the age of 3 months: 129/J, 129/ReJ, 129/SvJ, A/J, ALR/LtJ, ALS/LtJ, BUB/BnJ, C57BLKS/J, C57BR/cdJ, C57L/J, DBA/2J, I/LnJ, MA/MyJ, NOD/LtJ, NOR/LtJ, and SKH2/J. These hearing impaired strains may serve as models for some forms of human non-syndromic hearing loss and aid in the identification of the underlying genes.  (+info)

  • This thesis gives an overview of my work over the last four years on the development of analogue electronic building blocks for the auditory pathway, and their application to some models of processing in the auditory brainstem. (
  • The first example uses synchronized activity on auditory nerve fibres from two positions along the basilar membrane to obtain a high frequency selectivity and a representation of the sound which is independent of intensity. (
  • Although there is accumulating evidence that nonprimary auditory cortex regions posterior to the Heschl's gyrus (HG) are involved in spatial processing ( 21 - 26 ) and that areas anterior to HG process sound-identity cues such as speech ( 27 , 28 ) and pitch ( 29 ), the posterior nonprimary auditory cortex areas have been reported to respond strongly to phonetic stimuli as well ( 30 , 31 ). (
  • Development of auditory brainstem response to tone pip stimuli in the rat. (
  • The results suggest that both RPB and CPB provide the major auditory connections with the region related to directing eye movements towards stimuli of interest, and the dorsal prefrontal cortex for working memory. (
  • A research group from The University of Texas at San Antonio (TX, USA) has identified a new fear pathway in mice between the auditory cortex and the lateral amygdala that may play a role in fear-related behavior driven by auditory stimuli. (
  • Studies in the auditory system, for example, have demonstrated that performance in detecting sounds and gaps in noise, or the discrimination of lexical stimuli, varies with the power and phase of rhythmic activity between about 1 and 12 Hz ( 4 ⇓ ⇓ ⇓ ⇓ - 9 ). (
  • The algorithm of the auditory training was designed based on distinction between nonverbal and verbal stimuli of varying complexity, as well as tasks to improve memory (e.g., memorizing poetry). (
  • Speech-evoked auditory brainstem response (S-ABR) as an electrophysiologic test that uses speech stimuli to simulate real-life auditory conditions, reflects the performance of rostral brainstem centers, so structurally seems to be an appropriate candidate to examine the rostral part of the auditory efferent system. (
  • INTRODUCTION: The most successful tinnitus therapies are based on the psychological and the neurophysiological models, which suggest that tinnitus-related annoyance results from the dynamic interaction of auditory brain centers, limbic and autonomic nervous systems. (
  • Human neuroimaging studies suggest that localization and identification of relevant auditory objects are accomplished via parallel parietal-to-lateral-prefrontal "where" and anterior-temporal-to-inferior-frontal "what" pathways, respectively. (
  • We found a double dissociation in response adaptation to sound pairs with phonetic vs. spatial sound changes, demonstrating that the human nonprimary auditory cortex indeed processes speech-sound identity and location in parallel anterior "what" (in anterolateral Heschl's gyrus, anterior superior temporal gyrus, and posterior planum polare) and posterior "where" (in planum temporale and posterior superior temporal gyrus) pathways as early as ≈70-150 ms from stimulus onset. (
  • Human neuropsychological ( 5 - 8 ) and neuroimaging ( 9 - 20 ) studies have consistently shown anterior-temporal-to-inferior frontal "what" and parietal-to-lateral-prefrontal "where" auditory pathways, but whether such dual pathways exist also in the human nonprimary auditory cortex has remained a more controversial issue. (
  • This performance enhancement has been attributed to the auditory system's temporal ability to resolve speech fragments, or get "glimpses" or "looks" of speech, between the gaps of noise. (
  • Data from the rat trigeminal system suggest that the paralemniscal pathway may be specifically tuned to code low-frequency temporal information. (
  • We tested whether this phenomenon occurs in the auditory system by measuring the representation of temporal rate in lemniscal and paralemniscal auditory thalamus and cortex in guinea pig. (
  • We speculate that a paralemniscal pathway in the auditory system may be specifically tuned to code low frequency temporal information present in acoustic signals. (
  • Studies in adults demonstrate the effectiveness of RMHAs in mitigating hearing difficulties in conditions which are known to cause central auditory temporal distortions (multiple sclerosis, Friederich Ataxia)(Lewis et al. (
  • In the present study, we determined connections of three newly defined regions of auditory cortex with regions of the frontal lobe, and how two of these regions in the frontal lobe interconnect and connect to other portions of frontal cortex and the temporal lobe in macaque monkeys. (
  • We conceptualize auditory cortex as including a core of primary areas, a surrounding belt of auditory areas, a lateral parabelt of two divisions, and adjoining regions of temporal cortex with parabelt connections. (
  • Future modeling efforts might maintain the integrity of these two parallel pathways, optimized for fine spectral (Lower-SR) and fine temporal (High-SR) resolution, by separating rather than summing their respective outputs. (
  • This highly specialized synaptic arrangement, which is characterized by little convergence from disparate regions of the cochlear partition, is important in preserving temporal information transmitted by auditory nerve fibers. (
  • Octopus cells have close to the best temporal precision while firing, they decode the auditory timing code. (
  • however, they do exhibit changes in behavioral tests, suggesting the existence of deficits in temporal or non-auditory processing such as attention (2). (
  • The transverse temporal gyri , also called Heschl's gyri ( / ˈ h ɛ ʃ əl z ˈ dʒ aɪ r aɪ / ) or Heschl's convolutions , are gyri found in the area of primary auditory cortex buried within the lateral sulcus of the human brain , occupying Brodmann areas 41 and 42 . (
  • Transverse temporal gyri are the first cortical structures to process incoming auditory information. (
  • The transverse temporal gyri are active during auditory processing under fMRI for tone and semantic tasks. (
  • The role of transverse temporal gyri in auditory processing of tone is demonstrated by a study by Wong, Warrier et. (
  • The mustached bat auditory cortex contains a primary auditory cortex (A1) with a tonotopic map (reviewed in Suga, 1989 ). (
  • Some specializations for echolocation, such as over-representation of dominant harmonic frequencies of the echolocation call, are present in this pathway, but within the context of tonotopic representation. (
  • Microelectrode recordings were used to investigate the tonotopic organization of auditory cortex of macaque monkeys and guide the placement of injections of wheat germ agglutinin-horse radish peroxidase (WGA-HRP) and fluorescent dyes. (
  • Optical activation of the auditory pathway in ChR2 transgenic mice. (
  • Whittaker argued that regeneration takes place: fibers from the para-abducens nucleus, abducens nucleus, or median longitudinal fasciculus invade the cochlear nucleus (CN), leading to activation of the auditory pathway. (
  • Here, we compared the particle acceleration and pressure auditory thresholds of three species of fish with differing hearing specialisations, goldfish ( Carassius auratus , weberian ossicles), bigeye ( Pempheris adspersus , ligamentous hearing specialisation) and a third species with no swim bladder, the common triplefin ( Forstergyian lappillum ), using three different methods of determining particle acceleration. (
  • Our data further show that the "where" pathway is activated ≈30 ms earlier than the "what" pathway, possibly enabling the brain to use top-down spatial information in auditory object perception. (
  • Evidence of a double dissociation between processing of phonetic vs. spatial features is thus needed to determine whether the dual pathway model is valid for anterior vs. posterior human nonprimary auditory cortex areas. (
  • Dichotic listening studies of spatial attention suggest signal enhancements in auditory areas contralateral to the attended ear ( 38 , 42 , 43 ). (
  • The topography of frequency representation (i.e., its high-ordered spatial distribution within the auditory cortex) was shown by Woolsey and Walzl for the first time. (
  • Processing of auditory spatial cues in human cortex: an fMRI study. (
  • Interdependent encoding of pitch, timbre, and spatial location in auditory cortex. (
  • A method and system for improving auditory processing and increasing spatial awareness, wherein the voices of a musical composition are arranged, recorded and produced in particular combinations and at particular frequency levels according to a predetermined program designed to exercise auditory muscles, imprint the frequency map, and stimulate dendritic growth and synaptic organization. (
  • Central auditory processing disorder or deficit has been linked to many etiologies, including neurologic lesions or compromise of the central auditory nervous system. (
  • Although the incidence of children with central auditory processing disorder or deficit (CAPD) resulting from neurologic defects is considerably lower than that in children with CAPD, learning problems, and no identifiable neuropathology, some of the latter group also present with neurologic issues. (
  • Those diagnosed with CAPD with a presumed underlying neuromaturational source present central auditory systems that appear to mature more slowly than seen in normal children, often secondary to auditory deprivation and delayed myelin maturation in the subcortex, cortex, and corpus callosum. (
  • These delays theoretically can result in decreased performance on central auditory tests and in hearing difficulties, and are likely related to the long maturational course of the CANS. (
  • Here we report that prediction error is organized hierarchically along the central auditory pathway. (
  • Coding of environmental acoustic signals occurs at all levels of the central auditory pathway. (
  • A brain network involving limbic and other nonauditory regions is active in tinnitus and may be driven when spectrotemporal information conveyed by the damaged ear does not match that predicted by central auditory processing. (
  • The auditory pathway is divided into the outer, middle, and inner ear and the central auditory pathway. (
  • The authors emphasize that central auditory processing disorder (CAPD) significantly impairs speech perception in elderly people and makes difficult the rehabilitation of patients with presbycusis. (
  • Auditory and Vestibular Systems The Central Auditory System John F. Brugge Structure and Organization The major ascending auditory pathways of the brain stem and thalamus are shown schematically in Figure 1. (
  • Mild memory impairment may be associated with central auditory processing dysfunction, or difficulty hearing in complex situations with competing noise, such as hearing a single conversation amid several other conversations, according to a report in the July issue of Archives of Otolaryngology -- Head & Neck Surgery, one of the JAMA/Archives journals. (
  • children with phonological disorder present altered P300 suggesting involvement of the central auditory pathway, probably due to alterations in the auditory processing, presenting improvement in all components of LLAEP results after speech therapy. (
  • While the first two volumes describe the structure and function of auditory pathways, this one explains how these pathways lead to an animal's ability to localize and interpret sounds. (
  • and examine auditory discrimination and speech perception. (
  • Every time we listen-to speech, to music, to footsteps approaching or retreating-our auditory perception is the result of a long chain of diverse and intricate processes that unfold within the source of the sound itself, in the air, in our ears, and, most of all, in our brains. (
  • Toyohashi University of Technology has indicated that the relationship between attentional states in response to pictures and sounds and the emotions elicited by them may be different in visual perception and auditory perception. (
  • Functional status of auditory pathway is affected in type 2 diabetes. (
  • IMSEAR at SEARO: Functional status of auditory pathways in children with borderline intellectual functioning : Evoked potential study. (
  • A group of Dartmouth researchers has learned that the brain's auditory cortex, the part that handles information from your ears, holds on to musical memories. (
  • The first example uses synchronized activity on auditory nerve fibres from two positions along the basilar membrane to obtain a high frequency selectivity and a representation of the sound which is independent of intensity. (
  • The book is intended for students and postdocs starting in the auditory field, and researchers of related fields who wish to get an authoritative and up-to-date summary of the current state of auditory brainstem research. (
  • Frolenkov GI, Mammano F, Belyantseva IA, Coling D, Kachar B (2000) Two distinct Ca 2+ -dependent signaling pathways regulate the motor output of cochlear outer hair cells. (
  • In the inferior colliculus (IC) and the auditory cortex, physiological studies show that noise and echolocation calls are processed in segregated regions. (
  • While the functions of different neuronal types in the CN and the SOC are quite well understood, the nature of the code at the inferior colliculus (IC), medial geniculate (MGB) and primary auditory cortex (A1) levels are less well understood. (
  • The tragus and antitragus are the cartilaginous prominences that lie anterior and inferior respectively to the external auditory opening. (
  • However, although distinct prefrontal and parietal activations to attentional processing of "what" vs. "where" auditory information have been consistently reported ( 9 , 13 - 16 ), previous positron emission tomography and fMRI studies have failed to find evidence for feature-specific attentional effects for sound identity and location in the auditory cortex ( 37 , 39 ). (