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Journal of Neurophysiology Nov 2014This study investigates adaptation of high-frequency cortical responses [>60 Hz; high-gamma (HG)] to simple and complex sounds in human nonprimary auditory cortex. We...
This study investigates adaptation of high-frequency cortical responses [>60 Hz; high-gamma (HG)] to simple and complex sounds in human nonprimary auditory cortex. We used intracranial electrocorticographic recordings to measure event-related changes in HG power as a function of stimulus probability. Tone and speech stimuli were presented in a series of traditional oddball and control paradigms. We hypothesized that HG power attenuates with stimulus repetition over multiple concurrent time scales in auditory association cortex. Time-frequency analyses were performed to identify auditory-responsive sites. Single-trial analyses and quantitative modeling were then used to measure trial-to-trial changes in HG power for high (frequent), low (infrequent), and equal (control) stimulus probabilities. Results show strong reduction of HG responses to frequently repeated tones and speech, with no differences in responses to infrequent and equal-probability stimuli. Adaptation of the HG frequent response, and not stimulus-acoustic differences or deviance-detection enhancement effects, accounted for the differential responses observed for frequent and infrequent sounds. Adaptation of HG responses showed a rapid onset (less than two trials) with slower adaptation between consecutive, repeated trials (2-10 s) and across trials in a stimulus block (∼7 min). The auditory-evoked N100 response also showed repetition-related adaptation, consistent with previous human scalp and animal single-unit recordings. These findings indicate that HG responses are highly sensitive to the regularities of simple and complex auditory events and show adaptation on multiple concurrent time scales in human auditory association cortex.
Topics: Adaptation, Physiological; Adolescent; Adult; Auditory Cortex; Epilepsy; Evoked Potentials, Auditory; Female; Gamma Rhythm; Humans; Male
PubMed: 25122702
DOI: 10.1152/jn.00207.2014 -
Journal of Neurophysiology Sep 2009Responses of neural units in two areas of the medial auditory belt (middle medial area [MM] and rostral medial area [RM]) were tested with tones, noise bursts, monkey...
Responses of neural units in two areas of the medial auditory belt (middle medial area [MM] and rostral medial area [RM]) were tested with tones, noise bursts, monkey calls (MC), and environmental sounds (ES) in microelectrode recordings from two alert rhesus monkeys. For comparison, recordings were also performed from two core areas (primary auditory area [A1] and rostral area [R]) of the auditory cortex. All four fields showed cochleotopic organization, with best (center) frequency [BF(c)] gradients running in opposite directions in A1 and MM than in R and RM. The medial belt was characterized by a stronger preference for band-pass noise than for pure tones found medially to the core areas. Response latencies were shorter for the two more posterior (middle) areas MM and A1 than for the two rostral areas R and RM, reaching values as low as 6 ms for high BF(c) in MM and A1, and strongly depended on BF(c). The medial belt areas exhibited a higher selectivity to all stimuli, in particular to noise bursts, than the core areas. An increased selectivity to tones and noise bursts was also found in the anterior fields; the opposite was true for highly temporally modulated ES. Analysis of the structure of neural responses revealed that neurons were driven by low-level acoustic features in all fields. Thus medial belt areas RM and MM have to be considered early stages of auditory cortical processing. The anteroposterior difference in temporal processing indices suggests that R and RM may belong to a different hierarchical level or a different computational network than A1 and MM.
Topics: Acoustic Stimulation; Action Potentials; Animals; Auditory Cortex; Brain Mapping; Environment; Macaca mulatta; Male; Neurons; Noise; Reaction Time; Sound Localization; Spectrum Analysis; Statistics as Topic; Wakefulness
PubMed: 19571201
DOI: 10.1152/jn.00167.2009 -
The Journal of Neuroscience : the... Sep 2015A major challenge for sensory processing in the brain is considering stimulus context, such as stimulus probability, which may be relevant for survival. Excitatory...
A major challenge for sensory processing in the brain is considering stimulus context, such as stimulus probability, which may be relevant for survival. Excitatory neurons in auditory cortex, for example, adapt to repetitive tones in a stimulus-specific manner without fully generalizing to a low-probability deviant tone ("oddball") that breaks the preceding regularity. Whether such stimulus-specific adaptation (SSA) also prevails in inhibitory neurons and how it might relate to deviance detection remains elusive. We obtained whole-cell recordings from excitatory neurons and somatostatin- and parvalbumin-positive GABAergic interneurons in layer 2/3 of mouse auditory cortex and measured tone-evoked membrane potential responses. All cell types displayed SSA of fast ("early") subthreshold and suprathreshold responses with oddball tones of a deviant frequency eliciting enlarged responses compared with adapted standards. SSA was especially strong when oddball frequency matched neuronal preference. In addition, we identified a slower "late" response component (200-400 ms after tone onset), most clearly in excitatory and parvalbumin-positive neurons, which also displayed SSA. For excitatory neurons, this late component reflected genuine deviance detection. Moreover, intracellular blockade of NMDA receptors reduced early and late responses in excitatory but not parvalbumin-positive neurons. The late component in excitatory neurons thus shares time course, deviance detection, and pharmacological features with the deviant-evoked event-related potential known as mismatch negativity (MMN) and provides a potential link between neuronal SSA and MMN. In summary, our results suggest a two-phase cortical activation upon oddball stimulation, with oddball tones first reactivating the adapted auditory cortex circuitry and subsequently triggering delayed reverberating network activity. Significance statement: Understanding how the brain encodes sensory context in addition to stimulus feature has been a main focus in neuroscience. Using in vivo targeted whole-cell recordings from excitatory and inhibitory neurons of mouse primary auditory cortex, we report two temporally distinct components of membrane potential responses encoding oddball tones that break stimulus regularity. Both components display stimulus-specific adaptation upon oddball paradigm stimulation in the three recorded cell types. The late response component, in particular, carries signatures of genuine deviance detection. In excitatory but not parvalbumin-positive inhibitory neurons, both early and late components depend on NMDA receptor-signaling. Our work proposes a potential neuronal substrate of a known deviant-evoked event-related potential, which is of fundamental significance in basic and clinical neuroscience.
Topics: Adaptation, Physiological; Animals; Auditory Cortex; Evoked Potentials, Auditory; Female; GABAergic Neurons; Interneurons; Male; Mice; Pyramidal Cells; Reaction Time
PubMed: 26354921
DOI: 10.1523/JNEUROSCI.2240-15.2015 -
Biological Cybernetics Nov 2003Although the auditory cortex plays an important role in sound localization, that role is not well understood. In this paper, we examine the nature of spatial... (Review)
Review
Although the auditory cortex plays an important role in sound localization, that role is not well understood. In this paper, we examine the nature of spatial representation within the auditory cortex, focusing on three questions. First, are sound-source locations encoded by individual sharply tuned neurons or by activity distributed across larger neuronal populations? Second, do temporal features of neural responses carry information about sound-source location? Third, are any fields of the auditory cortex specialized for spatial processing? We present a brief review of recent work relevant to these questions along with the results of our investigations of spatial sensitivity in cat auditory cortex. Together, they strongly suggest that space is represented in a distributed manner, that response timing (notably first-spike latency) is a critical information-bearing feature of cortical responses, and that neurons in various cortical fields differ in both their degree of spatial sensitivity and their manner of spatial coding. The posterior auditory field (PAF), in particular, is well suited for the distributed coding of space and encodes sound-source locations partly by modulations of response latency. Studies of neurons recorded simultaneously from PAF and/or A1 reveal that spatial information can be decoded from the relative spike times of pairs of neurons - particularly when responses are compared between the two fields - thus partially compensating for the absence of an absolute reference to stimulus onset.
Topics: Acoustic Stimulation; Action Potentials; Animals; Auditory Cortex; Brain Mapping; Cats; Evoked Potentials, Auditory; Neurons; Sound Localization
PubMed: 14669014
DOI: 10.1007/s00422-003-0439-1 -
Human Brain Mapping Apr 2012The aim of this functional magnetic resonance imaging (fMRI) study was to identify human brain areas that are sensitive to the direction of auditory motion. Such...
The aim of this functional magnetic resonance imaging (fMRI) study was to identify human brain areas that are sensitive to the direction of auditory motion. Such directional sensitivity was assessed in a hypothesis-free manner by analyzing fMRI response patterns across the entire brain volume using a spherical-searchlight approach. In addition, we assessed directional sensitivity in three predefined brain areas that have been associated with auditory motion perception in previous neuroimaging studies. These were the primary auditory cortex, the planum temporale and the visual motion complex (hMT/V5+). Our whole-brain analysis revealed that the direction of sound-source movement could be decoded from fMRI response patterns in the right auditory cortex and in a high-level visual area located in the right lateral occipital cortex. Our region-of-interest-based analysis showed that the decoding of the direction of auditory motion was most reliable with activation patterns of the left and right planum temporale. Auditory motion direction could not be decoded from activation patterns in hMT/V5+. These findings provide further evidence for the planum temporale playing a central role in supporting auditory motion perception. In addition, our findings suggest a cross-modal transfer of directional information to high-level visual cortex in healthy humans.
Topics: Acoustic Stimulation; Adult; Auditory Cortex; Auditory Perception; Brain Mapping; Female; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Motion Perception; Photic Stimulation; Visual Cortex; Young Adult
PubMed: 21692141
DOI: 10.1002/hbm.21263 -
Current Biology : CB Nov 2021How the evolution of speech has transformed the human auditory cortex compared to other primates remains largely unknown. While primary auditory cortex is organized...
How the evolution of speech has transformed the human auditory cortex compared to other primates remains largely unknown. While primary auditory cortex is organized largely similarly in humans and macaques, the picture is much less clear at higher levels of the anterior auditory pathway, particularly regarding the processing of conspecific vocalizations (CVs). A "voice region" similar to the human voice-selective areas has been identified in the macaque right anterior temporal lobe with functional MRI; however, its anatomical localization, seemingly inconsistent with that of the human temporal voice areas (TVAs), has suggested a "repositioning of the voice area" in recent human evolution. Here we report a functional homology in the cerebral processing of vocalizations by macaques and humans, using comparative fMRI and a condition-rich auditory stimulation paradigm. We find that the anterior temporal lobe of both species possesses cortical voice areas that are bilateral and not only prefer conspecific vocalizations but also implement a representational geometry categorizing them apart from all other sounds in a species-specific but homologous manner. These results reveal a more similar functional organization of higher-level auditory cortex in macaques and humans than currently known.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Perception; Brain Mapping; Humans; Macaca; Magnetic Resonance Imaging; Primates; Vocalization, Animal
PubMed: 34506729
DOI: 10.1016/j.cub.2021.08.043 -
Journal of Neurophysiology Oct 2018Speech perception relies on the accurate resolution of brief, successive sounds that change rapidly over time. Deficits in the perception of such sounds, indicated by a...
Speech perception relies on the accurate resolution of brief, successive sounds that change rapidly over time. Deficits in the perception of such sounds, indicated by a reduced ability to detect signals during auditory backward masking, strongly relate to language processing difficulties in children. Backward masking during normal development has a longer maturational trajectory than many other auditory percepts, implicating the involvement of central auditory neural mechanisms with protracted developmental time courses. Despite the importance of this percept, its neural correlates are not well described at any developmental stage. We therefore measured auditory cortical responses to masked signals in juvenile and adult Mongolian gerbils and quantified the detection ability of individual neurons and neural populations in a manner comparable with psychoacoustic measurements. Perceptually, auditory backward masking manifests as higher thresholds for detection of a short signal followed by a masker than for the same signal in silence. Cortical masking was driven by a combination of suppressed responses to the signal and a reduced dynamic range available for signal detection in the presence of the masker. Both coding elements contributed to greater masked threshold shifts in juveniles compared with adults, but signal-evoked firing suppression was more pronounced in juveniles. Neural threshold shifts were a better match to human psychophysical threshold shifts when quantified with a longer temporal window that included the response to the delayed masker, suggesting that temporally selective listening may contribute to age-related differences in backward masking. NEW & NOTEWORTHY In children, auditory detection of backward masked signals is immature well into adolescence, and detection deficits correlate with problems in speech processing. Our auditory cortical recordings reveal immature backward masking in adolescent animals that mirrors the prolonged development seen in children. This is driven by both signal-evoked suppression and dynamic range reduction. An extended window of analysis suggests that differences in temporally focused listening may contribute to late maturing thresholds for backward masked signals.
Topics: Animals; Auditory Cortex; Evoked Potentials, Auditory; Female; Gerbillinae; Male; Neurons; Perceptual Masking; Sensory Thresholds
PubMed: 29995598
DOI: 10.1152/jn.00114.2018 -
The Journal of Neuroscience : the... Apr 2003Understanding spoken language requires a complex series of processing stages to translate speech sounds into meaning. In this study, we use functional magnetic resonance... (Clinical Trial)
Clinical Trial
Understanding spoken language requires a complex series of processing stages to translate speech sounds into meaning. In this study, we use functional magnetic resonance imaging to explore the brain regions that are involved in spoken language comprehension, fractionating this system into sound-based and more abstract higher-level processes. We distorted English sentences in three acoustically different ways, applying each distortion to varying degrees to produce a range of intelligibility (quantified as the number of words that could be reported) and collected whole-brain echo-planar imaging data from 12 listeners using sparse imaging. The blood oxygenation level-dependent signal correlated with intelligibility along the superior and middle temporal gyri in the left hemisphere and in a less-extensive homologous area on the right, the left inferior frontal gyrus (LIFG), and the left hippocampus. Regions surrounding auditory cortex, bilaterally, were sensitive to intelligibility but also showed a differential response to the three forms of distortion, consistent with sound-form-based processes. More distant intelligibility-sensitive regions within the superior and middle temporal gyri, hippocampus, and LIFG were insensitive to the acoustic form of sentences, suggesting more abstract nonacoustic processes. The hierarchical organization suggested by these results is consistent with cognitive models and auditory processing in nonhuman primates. Areas that were particularly active for distorted speech conditions and, thus, might be involved in compensating for distortion, were found exclusively in the left hemisphere and partially overlapped with areas sensitive to intelligibility, perhaps reflecting attentional modulation of auditory and linguistic processes.
Topics: Acoustic Stimulation; Adolescent; Adult; Auditory Cortex; Auditory Pathways; Brain Mapping; Comprehension; Female; Frontal Lobe; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Pilot Projects; Reference Values; Sound Spectrography; Speech Discrimination Tests; Speech Intelligibility; Temporal Lobe; Verbal Behavior
PubMed: 12716950
DOI: 10.1523/JNEUROSCI.23-08-03423.2003 -
Hearing Research Mar 2008Temporal envelope processing in the human auditory cortex has an important role in language analysis. In this paper, depth recordings of local field potentials in...
Temporal envelope processing in the human auditory cortex has an important role in language analysis. In this paper, depth recordings of local field potentials in response to amplitude modulated white noises were used to design maps of activation in primary, secondary and associative auditory areas and to study the propagation of the cortical activity between them. The comparison of activations between auditory areas was based on a signal-to-noise ratio associated with the response to amplitude modulation (AM). The functional connectivity between cortical areas was quantified by the directed coherence (DCOH) applied to auditory evoked potentials. This study shows the following reproducible results on twenty subjects: (1) the primary auditory cortex (PAC), the secondary cortices (secondary auditory cortex (SAC) and planum temporale (PT)), the insular gyrus, the Brodmann area (BA) 22 and the posterior part of T1 gyrus (T1Post) respond to AM in both hemispheres. (2) A stronger response to AM was observed in SAC and T1Post of the left hemisphere independent of the modulation frequency (MF), and in the left BA22 for MFs 8 and 16Hz, compared to those in the right. (3) The activation and propagation features emphasized at least four different types of temporal processing. (4) A sequential activation of PAC, SAC and BA22 areas was clearly visible at all MFs, while other auditory areas may be more involved in parallel processing upon a stream originating from primary auditory area, which thus acts as a distribution hub. These results suggest that different psychological information is carried by the temporal envelope of sounds relative to the rate of amplitude modulation.
Topics: Artifacts; Auditory Cortex; Auditory Pathways; Brain Mapping; Evoked Potentials, Auditory; Functional Laterality; Humans; Models, Neurological
PubMed: 18255243
DOI: 10.1016/j.heares.2007.12.003 -
Cerebral Cortex (New York, N.Y. : 1991) Jan 2017In the ventral stream of the primate auditory cortex, cortico-cortical projections emanate from the primary auditory cortex (AI) along 2 principal axes: one...
In the ventral stream of the primate auditory cortex, cortico-cortical projections emanate from the primary auditory cortex (AI) along 2 principal axes: one mediolateral, the other caudorostral. Connections in the mediolateral direction from core, to belt, to parabelt, have been well described, but less is known about the flow of information along the supratemporal plane (STP) in the caudorostral dimension. Neuroanatomical tracers were injected throughout the caudorostral extent of the auditory core and rostral STP by direct visualization of the cortical surface. Auditory cortical areas were distinguished by SMI-32 immunostaining for neurofilament, in addition to established cytoarchitectonic criteria. The results describe a pathway comprising step-wise projections from AI through the rostral and rostrotemporal fields of the core (R and RT), continuing to the recently identified rostrotemporal polar field (RTp) and the dorsal temporal pole. Each area was strongly and reciprocally connected with the areas immediately caudal and rostral to it, though deviations from strictly serial connectivity were observed. In RTp, inputs converged from core, belt, parabelt, and the auditory thalamus, as well as higher order cortical regions. The results support a rostrally directed flow of auditory information with complex and recurrent connections, similar to the ventral stream of macaque visual cortex.
Topics: Animals; Auditory Cortex; Auditory Pathways; Female; Macaca mulatta; Male; Neuroanatomical Tract-Tracing Techniques; Neurons
PubMed: 26620266
DOI: 10.1093/cercor/bhv277