Representation of Auditory-Filter Phase Characteristics in the Cortex of Human Listeners

2008 ◽  
Vol 99 (3) ◽  
pp. 1152-1162 ◽  
Author(s):  
André Rupp ◽  
Norman Sieroka ◽  
Alexander Gutschalk ◽  
Torsten Dau
Keyword(s):  
Auditory Cortex ◽  
Neural Activity ◽  
Auditory Processing ◽  
Pure Tone ◽  
Basilar Membrane ◽  
Neural Representation ◽  
Auditory Filter ◽  
Long Duration ◽  
Auditory Evoked Fields ◽  
Evoked Fields

Harmonic tone complexes with component phases, adjusted using a variant of a method proposed by Schroeder, can produce pure-tone masked thresholds differing by >20 dB. This phenomenon has been qualitatively explained by the phase characteristics of the auditory filters on the basilar membrane, which differently affect the flat envelopes of the Schroeder-phase maskers. We examined the influence of auditory-filter phase characteristics on the neural representation in the auditory cortex by investigating cortical auditory evoked fields (AEFs). We found that the P1m component exhibited larger amplitudes when a long-duration tone was presented in a repeating linearly downward sweeping (Schroeder positive, or m+) masker than in a repeating linearly upward sweeping (Schroeder negative, or m−) masker. We also examined the neural representation of short-duration tone pulses presented at different temporal positions within a single period of three maskers differing in their component phases ( m+, m−, and sine phase m0). The P1m amplitude varied with the position of the tone pulse in the masker and depended strongly on the masker waveform. The neuromagnetic results in all cases were consistent with the perceptual data obtained with the same stimuli and with results from simulations of neural activity at the output of cochlear preprocessing. These findings demonstrate that phase effects in peripheral auditory processing are accurately reflected up to the level of the auditory cortex.

Potentials evoked by sound in the auditory cortex of the cat

1961 ◽  
Vol 200 (6) ◽  
pp. 1219-1225 ◽  
Author(s):  
Robert J. Gumnit ◽  
Robert G. Grossman
Keyword(s):  
Auditory Cortex ◽  
White Noise ◽  
Pure Tone ◽  
Evoked Response ◽  
Moderate Intensity ◽  
Positive Potential ◽  
Positive Wave ◽  
Natural Sleep ◽  
Negative Shift ◽  
Long Duration

The electrical responses of the auditory cortex of awake, loosely restrained cats were examined with chronically implanted calomel electrodes and d-c recording systems. Stimulation with a single click evoked a complex triphasic response in which a large surface positive potential (duration, 250 msec) followed the classic diphasic response. This second positive wave was absent in natural sleep and under light barbiturate anesthesia. A similar late positive wave of long duration, evoked by a flash of light, was found in the visual cortex. A rapid series of clicks evoked a surface negative shift which was maintained for the duration of the stimulus. A tone or white noise presented for several seconds evoked a negative shift of the same general form. A pure tone of moderate intensity presented simultaneously with a click greatly enhanced the click-evoked response. White noise of moderate intensity presented simultaneously with a click diminished the size of the click-evoked response.

scholarly journals Brain Frequency-Specific Changes in the Spontaneous Neural Activity Are Associated With Cognitive Impairment in Patients With Presbycusis

2021 ◽  
Vol 13 ◽  
Author(s):  
Fuxin Ren ◽  
Wen Ma ◽  
Wei Zong ◽  
Ning Li ◽  
Xiao Li ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Auditory Cortex ◽  
Neural Activity ◽  
Auditory Processing ◽  
Low Frequency ◽  
Frontal Eye Field ◽  
Functional Coupling ◽  
Frequency Bands ◽  
Spontaneous Neural Activity ◽  
Key Nodes

Presbycusis (PC) is characterized by preferential hearing loss at high frequencies and difficulty in speech recognition in noisy environments. Previous studies have linked PC to cognitive impairment, accelerated cognitive decline and incident Alzheimer’s disease. However, the neural mechanisms of cognitive impairment in patients with PC remain unclear. Although resting-state functional magnetic resonance imaging (rs-fMRI) studies have explored low-frequency oscillation (LFO) connectivity or amplitude of PC-related neural activity, it remains unclear whether the abnormalities occur within all frequency bands or within specific frequency bands. Fifty-one PC patients and fifty-one well-matched normal hearing controls participated in this study. The LFO amplitudes were investigated using the amplitude of low-frequency fluctuation (ALFF) at different frequency bands (slow-4 and slow-5). PC patients showed abnormal LFO amplitudes in the Heschl’s gyrus, dorsolateral prefrontal cortex (dlPFC), frontal eye field and key nodes of the speech network exclusively in slow-4, which suggested that abnormal spontaneous neural activity in PC was frequency dependent. Our findings also revealed that stronger functional connectivity between the dlPFC and the posterodorsal stream of auditory processing, as well as lower functional coupling between the PCC and key nodes of the DMN, which were associated with cognitive impairments in PC patients. Our study might underlie the cross-modal plasticity and higher-order cognitive participation of the auditory cortex after partial hearing deprivation. Our findings indicate that frequency-specific analysis of ALFF could provide valuable insights into functional alterations in the auditory cortex and non-auditory regions involved in cognitive impairment associated with PC.

scholarly journals A complex feature-based representation of vocalizations emerges in the superficial layers of primary auditory cortex

2021 ◽  
Author(s):  
Pilar Montes-Lourido ◽  
Manaswini Kar ◽  
Stephen V David ◽  
Srivatsun Sadagopan
Keyword(s):  
Auditory Cortex ◽  
Auditory Processing ◽  
Receptive Fields ◽  
Primary Auditory Cortex ◽  
Neural Representation ◽  
Specific Information ◽  
Intermediate Step ◽  
Stimulus Information ◽  
Feature Selectivity ◽  
Feature Based

Early in auditory processing, neural responses faithfully reflect acoustic input. At higher stages of auditory processing, however, neurons become selective for particular call types, eventually leading to specialized regions of cortex that preferentially process calls at the highest auditory processing stages. We previously proposed that an intermediate step in how non-selective responses are transformed into call-selective responses is the detection of informative call features. But how neural selectivity for informative call features emerges from non-selective inputs, whether feature selectivity gradually emerges over the processing hierarchy, and how stimulus information is represented in non-selective and feature-selective populations remain open questions. In this study, using unanesthetized guinea pigs, a highly vocal and social rodent, as an animal model, we characterized the neural representation of calls in three auditory processing stages: the thalamus (vMGB), and thalamorecipient (L4) and superficial layers (L2/3) of primary auditory cortex (A1). We found that neurons in vMGB and A1 L4 did not exhibit call-selective responses and responded throughout the call durations. However, A1 L2/3 neurons showed high call-selectivity with about a third of neurons responding to only one or two call types. These A1 L2/3 neurons only responded to restricted portions of calls suggesting that they were highly selective for call features. Receptive fields of these A1 L2/3 neurons showed complex spectrotemporal structures that could underlie their high call feature selectivity. Information theoretic analysis revealed that in A1 L4 stimulus information was distributed over the population and was spread out over the call durations. In contrast, in A1 L2/3, individual neurons showed brief bursts of high stimulus-specific information, and conveyed high levels of information per spike. These data demonstrate that a transformation in the neural representation of calls occurs between A1 L4 and A1 L2/3, leading to the emergence of a feature-based representation of calls in A1 L2/3. Our data thus suggest that observed cortical specializations for call processing emerge in A1, and set the stage for further mechanistic studies.

scholarly journals Dissociation of task engagement and arousal effects in auditory cortex and midbrain

2020 ◽  
Author(s):  
Daniela Saderi ◽  
Zachary P. Schwartz ◽  
Charlie R. Heller ◽  
Jacob R. Pennington ◽  
Stephen V. David
Keyword(s):  
Auditory Cortex ◽  
Neural Activity ◽  
Auditory Processing ◽  
Neural Coding ◽  
Primary Auditory Cortex ◽  
Task Engagement ◽  
State Variables ◽  
Neural Populations ◽  
Global Fluctuations ◽  
Specific Control

AbstractThe brain’s representation of sound is influenced by multiple aspects of internal behavioral state. Following engagement in an auditory discrimination task, both generalized arousal and task-specific control signals can influence auditory processing. To isolate effects of these state variables on auditory processing, we recorded single-unit activity from primary auditory cortex (A1) and the inferior colliculus (IC) of ferrets as they engaged in a go/no-go tone detection task while simultaneously monitoring arousal via pupillometry. We used a generalized linear model to isolate the contributions of task engagement and arousal on spontaneous and evoked neural activity. Fluctuations in pupil-indexed arousal were correlated with task engagement, but these two variables could be dissociated in most experiments. In both A1 and IC, individual units could be modulated by task and/or arousal, but the two state variables affected independent neural populations. Arousal effects were more prominent in IC, while arousal and engagement effects occurred with about equal frequency in A1. These results indicate that some changes in neural activity attributed to task engagement in previous studies should in fact be attributed to global fluctuations in arousal. Arousal effects also explain some persistent changes in neural activity observed in passive conditions post-behavior. Together, these results indicate a hierarchy in the auditory system, where generalized arousal enhances activity in the midbrain and cortex, while task-specific changes in neural coding become more prominent in cortex.

Short-Term Sound Temporal Envelope Characteristics Determine Multisecond Time Patterns of Activity in Human Auditory Cortex as Shown by fMRI

2005 ◽  
Vol 93 (1) ◽  
pp. 210-222 ◽  
Author(s):  
Michael P. Harms ◽  
John J. Guinan ◽  
Irina S. Sigalovsky ◽  
Jennifer R. Melcher
Keyword(s):  
Auditory Cortex ◽  
Neural Activity ◽  
Auditory Processing ◽  
Activity Patterns ◽  
Noise Burst ◽  
Sound Level ◽  
High Rate ◽  
Temporal Envelope ◽  
Time Patterns ◽  
Human Auditory Cortex

Functional magnetic resonance imaging (fMRI) of human auditory cortex has demonstrated a striking range of temporal waveshapes in responses to sound. Prolonged (30 s) low-rate (2/s) noise burst trains elicit “sustained” responses, whereas high-rate (35/s) trains elicit “phasic” responses with peaks just after train onset and offset. As a step toward understanding the significance of these responses for auditory processing, the present fMRI study sought to resolve exactly which features of sound determine cortical response waveshape. The results indicate that sound temporal envelope characteristics, but not sound level or bandwidth, strongly influence response waveshapes, and thus the underlying time patterns of neural activity. The results show that sensitivity to sound temporal envelope holds in both primary and nonprimary cortical areas, but nonprimary areas show more pronounced phasic responses for some types of stimuli (higher-rate trains, continuous noise), indicating more prominent neural activity at sound onset and offset. It has been hypothesized that the neural activity underlying the onset and offset peaks reflects the beginning and end of auditory perceptual events. The present data support this idea because sound temporal envelope, the sound characteristic that most strongly influences whether fMRI responses are phasic, also strongly influences whether successive stimuli (e.g., the bursts of a train) are perceptually grouped into a single auditory event. Thus fMRI waveshape may provide a window onto neural activity patterns that reflect the segmentation of our auditory environment into distinct, meaningful events.

How anatomical asymmetry of human auditory cortex can lead to a rightward bias in auditory evoked fields

NeuroImage ◽  
2013 ◽  
Vol 74 ◽  
pp. 22-29 ◽  
Author(s):  
Marnie E. Shaw ◽  
Matti S. Hämäläinen ◽  
Alexander Gutschalk
Keyword(s):  
Auditory Cortex ◽  
Auditory Evoked Fields ◽  
Evoked Fields ◽  
Human Auditory Cortex

scholarly journals MEG auditory evoked fields suggest altered structural/functional asymmetry in primary but not secondary auditory cortex in bipolar disorder

2009 ◽  
Vol 11 (4) ◽  
pp. 371-381 ◽  
Author(s):  
Martin Reite ◽  
Peter Teale ◽  
Donald C Rojas ◽  
Erik Reite ◽  
Ryan Asherin ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Auditory Cortex ◽  
Functional Asymmetry ◽  
Auditory Evoked Fields ◽  
Evoked Fields

Evidence for Linear but Not Helical Automatic Representation of Pitch in the Human Auditory System

2019 ◽  
Vol 31 (5) ◽  
pp. 669-685 ◽  
Author(s):  
Tamar I. Regev ◽  
Israel Nelken ◽  
Leon Y. Deouell
Keyword(s):  
Working Memory ◽  
Cognitive Processes ◽  
Neural Activity ◽  
Pure Tone ◽  
Automatic Detection ◽  
Complex Tone ◽  
Neural Representation ◽  
Pitch Height ◽  
G 21 ◽  
Complex Tones

The perceptual organization of pitch is frequently described as helical, with a monotonic dimension of pitch height and a circular dimension of pitch chroma, accounting for the repeating structure of the octave. Although the neural representation of pitch height is widely studied, the way in which pitch chroma representation is manifested in neural activity is currently debated. We tested the automaticity of pitch chroma processing using the MMN—an ERP component indexing automatic detection of deviations from auditory regularity. Musicians trained to classify pure or complex tones across four octaves, based on chroma—C versus G (21 participants, Experiment 1) or C versus F# (27, Experiment 2). Next, they were passively exposed to MMN protocols designed to test automatic detection of height and chroma deviations. Finally, in an “attend chroma” block, participants had to detect the chroma deviants in a sequence similar to the passive MMN sequence. The chroma deviant tones were accurately detected in the training and the attend chroma parts both for pure and complex tones, with a slightly better performance for complex tones. However, in the passive blocks, a significant MMN was found only to height deviations and complex tone chroma deviations, but not to pure tone chroma deviations, even for perfect performers in the active tasks. These results indicate that, although height is represented preattentively, chroma is not. Processing the musical dimension of chroma may require higher cognitive processes, such as attention and working memory.

Bottom-Up Driven Involuntary Auditory Evoked Field Change: Constant Sound Sequencing Amplifies But Does Not Sharpen Neural Activity

2010 ◽  
Vol 103 (1) ◽  
pp. 244-249 ◽  
Author(s):  
Hidehiko Okamoto ◽  
Henning Stracke ◽  
Lothar Lagemann ◽  
Christo Pantev
Keyword(s):  
Neural Activity ◽  
Frequency Tuning ◽  
Sound Signal ◽  
Neural Processing ◽  
Noisy Environments ◽  
Auditory Neurons ◽  
Bottom Up ◽  
Auditory Evoked Fields ◽  
Evoked Fields ◽  
Random Sequencing

The capability of involuntarily tracking certain sound signals during the simultaneous presence of noise is essential in human daily life. Previous studies have demonstrated that top-down auditory focused attention can enhance excitatory and inhibitory neural activity, resulting in sharpening of frequency tuning of auditory neurons. In the present study, we investigated bottom-up driven involuntary neural processing of sound signals in noisy environments by means of magnetoencephalography. We contrasted two sound signal sequencing conditions: “constant sequencing” versus “random sequencing.” Based on a pool of 16 different frequencies, either identical (constant sequencing) or pseudorandomly chosen (random sequencing) test frequencies were presented blockwise together with band-eliminated noises to nonattending subjects. The results demonstrated that the auditory evoked fields elicited in the constant sequencing condition were significantly enhanced compared with the random sequencing condition. However, the enhancement was not significantly different between different band-eliminated noise conditions. Thus the present study confirms that by constant sound signal sequencing under nonattentive listening the neural activity in human auditory cortex can be enhanced, but not sharpened. Our results indicate that bottom-up driven involuntary neural processing may mainly amplify excitatory neural networks, but may not effectively enhance inhibitory neural circuits.

Interhemispheric asymmetry in the auditory evoked fields for pure tone stimuli

1996 ◽  
Vol 98 (4) ◽  
pp. 46
Author(s):  
A. Kanno ◽  
N. Nakasato ◽  
K. Seki ◽  
K.T. Kawamura ◽  
S. Ohtomo ◽  
...  
Keyword(s):  
Pure Tone ◽  
Interhemispheric Asymmetry ◽  
Auditory Evoked Fields ◽  
Evoked Fields
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