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Lestang JH, Cai H, Averbeck BB, Cohen YE. Functional network properties of the auditory cortex. Hear Res 2023; 433:108768. [PMID: 37075536 PMCID: PMC10205700 DOI: 10.1016/j.heares.2023.108768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 03/27/2023] [Accepted: 04/11/2023] [Indexed: 04/21/2023]
Abstract
The auditory system transforms auditory stimuli from the external environment into perceptual auditory objects. Recent studies have focused on the contribution of the auditory cortex to this transformation. Other studies have yielded important insights into the contributions of neural activity in the auditory cortex to cognition and decision-making. However, despite this important work, the relationship between auditory-cortex activity and behavior/perception has not been fully elucidated. Two of the more important gaps in our understanding are (1) the specific and differential contributions of different fields of the auditory cortex to auditory perception and behavior and (2) the way networks of auditory neurons impact and facilitate auditory information processing. Here, we focus on recent work from non-human-primate models of hearing and review work related to these gaps and put forth challenges to further our understanding of how single-unit activity and network activity in different cortical fields contribution to behavior and perception.
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Affiliation(s)
- Jean-Hugues Lestang
- Departments of Otorhinolaryngology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Huaizhen Cai
- Departments of Otorhinolaryngology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bruno B Averbeck
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Yale E Cohen
- Departments of Otorhinolaryngology, University of Pennsylvania, Philadelphia, PA 19104, USA; Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA; Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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See JZ, Homma NY, Atencio CA, Sohal VS, Schreiner CE. Information diversity in individual auditory cortical neurons is associated with functionally distinct coordinated neuronal ensembles. Sci Rep 2021; 11:4064. [PMID: 33603027 PMCID: PMC7893178 DOI: 10.1038/s41598-021-83565-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/18/2021] [Indexed: 01/31/2023] Open
Abstract
Neuronal activity in auditory cortex is often highly synchronous between neighboring neurons. Such coordinated activity is thought to be crucial for information processing. We determined the functional properties of coordinated neuronal ensembles (cNEs) within primary auditory cortical (AI) columns relative to the contributing neurons. Nearly half of AI cNEs showed robust spectro-temporal receptive fields whereas the remaining cNEs showed little or no acoustic feature selectivity. cNEs can therefore capture either specific, time-locked information of spectro-temporal stimulus features or reflect stimulus-unspecific, less-time specific processing aspects. By contrast, we show that individual neurons can represent both of those aspects through membership in multiple cNEs with either high or absent feature selectivity. These associations produce functionally heterogeneous spikes identifiable by instantaneous association with different cNEs. This demonstrates that single neuron spike trains can sequentially convey multiple aspects that contribute to cortical processing, including stimulus-specific and unspecific information.
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Affiliation(s)
- Jermyn Z. See
- grid.266102.10000 0001 2297 6811Weill Institute for Neuroscience, Kavli Institute for Fundamental Neuroscience, and Sloan-Swartz Center for Theoretical Neurobiology, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158-0444 USA ,Department of Otolaryngology-Head and Neck Surgery, Coleman Memorial Laboratory, University of Caliornia, San Francisco, USA
| | - Natsumi Y. Homma
- grid.266102.10000 0001 2297 6811Weill Institute for Neuroscience, Kavli Institute for Fundamental Neuroscience, and Sloan-Swartz Center for Theoretical Neurobiology, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158-0444 USA ,Department of Otolaryngology-Head and Neck Surgery, Coleman Memorial Laboratory, University of Caliornia, San Francisco, USA
| | - Craig A. Atencio
- grid.266102.10000 0001 2297 6811Weill Institute for Neuroscience, Kavli Institute for Fundamental Neuroscience, and Sloan-Swartz Center for Theoretical Neurobiology, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158-0444 USA ,Department of Otolaryngology-Head and Neck Surgery, Coleman Memorial Laboratory, University of Caliornia, San Francisco, USA
| | - Vikaas S. Sohal
- grid.266102.10000 0001 2297 6811Weill Institute for Neuroscience, Kavli Institute for Fundamental Neuroscience, and Sloan-Swartz Center for Theoretical Neurobiology, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158-0444 USA ,grid.266102.10000 0001 2297 6811Department of Psychiatry, University of California, San Francisco, USA
| | - Christoph E. Schreiner
- grid.266102.10000 0001 2297 6811Weill Institute for Neuroscience, Kavli Institute for Fundamental Neuroscience, and Sloan-Swartz Center for Theoretical Neurobiology, University of California, San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158-0444 USA ,Department of Otolaryngology-Head and Neck Surgery, Coleman Memorial Laboratory, University of Caliornia, San Francisco, USA
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3
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Postal O, Dupont T, Bakay W, Dominique N, Petit C, Michalski N, Gourévitch B. Spontaneous Mouse Behavior in Presence of Dissonance and Acoustic Roughness. Front Behav Neurosci 2020; 14:588834. [PMID: 33132864 PMCID: PMC7578920 DOI: 10.3389/fnbeh.2020.588834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/08/2020] [Indexed: 11/13/2022] Open
Abstract
According to a novel hypothesis (Arnal et al., 2015, Current Biology 25:2051-2056), auditory roughness, or temporal envelope modulations between 30 and 150 Hz, are present in both natural and artificial human alarm signals, which boosts the detection of these alarms in various tasks. These results also shed new light on the unpleasantness of dissonant sounds to humans, which builds upon the high level of roughness present in such sounds. However, it is not clear whether this hypothesis also applies to other species, such as rodents. In particular, whether consonant/dissonant chords, and particularly whether auditory roughness, can trigger unpleasant sensations in mice remains unknown. Using an autonomous behavioral system, which allows the monitoring of mouse behavior over a period of weeks, we observed that C57Bl6J mice did not show any preference for consonant chords. In addition, we found that mice showed a preference for rough sounds over sounds having amplitude modulations in their temporal envelope outside the "rough" range. These results suggest that some emotional features carried by the acoustic temporal envelope are likely to be species-specific.
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Affiliation(s)
- Olivier Postal
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Typhaine Dupont
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
| | - Warren Bakay
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
| | - Noémi Dominique
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
| | - Christine Petit
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
- Syndrome de Usher et Autres Atteintes Rétino-Cochléaires, Institut de la Vision, Paris, France
- Collège de France, Paris, France
| | | | - Boris Gourévitch
- Institut de l’Audition, Institut Pasteur, INSERM, Paris, France
- CNRS, Paris, France
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4
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See JZ, Atencio CA, Sohal VS, Schreiner CE. Coordinated neuronal ensembles in primary auditory cortical columns. eLife 2018; 7:e35587. [PMID: 29869986 PMCID: PMC6017807 DOI: 10.7554/elife.35587] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/03/2018] [Indexed: 12/15/2022] Open
Abstract
The synchronous activity of groups of neurons is increasingly thought to be important in cortical information processing and transmission. However, most studies of processing in the primary auditory cortex (AI) have viewed neurons as independent filters; little is known about how coordinated AI neuronal activity is expressed throughout cortical columns and how it might enhance the processing of auditory information. To address this, we recorded from populations of neurons in AI cortical columns of anesthetized rats and, using dimensionality reduction techniques, identified multiple coordinated neuronal ensembles (cNEs), which are groups of neurons with reliable synchronous activity. We show that cNEs reflect local network configurations with enhanced information encoding properties that cannot be accounted for by stimulus-driven synchronization alone. Furthermore, similar cNEs were identified in both spontaneous and evoked activity, indicating that columnar cNEs are stable functional constructs that may represent principal units of information processing in AI.
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Affiliation(s)
- Jermyn Z See
- UCSF Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
- Coleman Memorial Laboratory, University of California, San Francisco, San Francisco, United States
- Department of Otolaryngology - Head and Neck Surgery, University of California, San Francisco, San Francisco, United States
- Department of Psychiatry, University of California, San Francisco, United States
| | - Craig A Atencio
- UCSF Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
- Coleman Memorial Laboratory, University of California, San Francisco, San Francisco, United States
- Department of Otolaryngology - Head and Neck Surgery, University of California, San Francisco, San Francisco, United States
| | - Vikaas S Sohal
- UCSF Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
- Department of Psychiatry, University of California, San Francisco, United States
| | - Christoph E Schreiner
- UCSF Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
- Coleman Memorial Laboratory, University of California, San Francisco, San Francisco, United States
- Department of Otolaryngology - Head and Neck Surgery, University of California, San Francisco, San Francisco, United States
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5
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Hoglen NEG, Larimer P, Phillips EAK, Malone BJ, Hasenstaub AR. Amplitude modulation coding in awake mice and squirrel monkeys. J Neurophysiol 2018; 119:1753-1766. [PMID: 29364073 DOI: 10.1152/jn.00101.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Both mice and primates are used to model the human auditory system. The primate order possesses unique cortical specializations that govern auditory processing. Given the power of molecular and genetic tools available in the mouse model, it is essential to understand the similarities and differences in auditory cortical processing between mice and primates. To address this issue, we directly compared temporal encoding properties of neurons in the auditory cortex of awake mice and awake squirrel monkeys (SQMs). Stimuli were drawn from a sinusoidal amplitude modulation (SAM) paradigm, which has been used previously both to characterize temporal precision and to model the envelopes of natural sounds. Neural responses were analyzed with linear template-based decoders. In both species, spike timing information supported better modulation frequency discrimination than rate information, and multiunit responses generally supported more accurate discrimination than single-unit responses from the same site. However, cortical responses in SQMs supported better discrimination overall, reflecting superior temporal precision and greater rate modulation relative to the spontaneous baseline and suggesting that spiking activity in mouse cortex was less strictly regimented by incoming acoustic information. The quantitative differences we observed between SQM and mouse cortex support the idea that SQMs offer advantages for modeling precise responses to fast envelope dynamics relevant to human auditory processing. Nevertheless, our results indicate that cortical temporal processing is qualitatively similar in mice and SQMs and thus recommend the mouse model for mechanistic questions, such as development and circuit function, where its substantial methodological advantages can be exploited. NEW & NOTEWORTHY To understand the advantages of different model organisms, it is necessary to directly compare sensory responses across species. Contrasting temporal processing in auditory cortex of awake squirrel monkeys and mice, with parametrically matched amplitude-modulated tone stimuli, reveals a similar role of timing information in stimulus encoding. However, disparities in response precision and strength suggest that anatomical and biophysical differences between squirrel monkeys and mice produce quantitative but not qualitative differences in processing strategy.
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Affiliation(s)
- Nerissa E G Hoglen
- Center for Integrative Neuroscience, University of California , San Francisco, California.,Department of Otolaryngology-Head and Neck Surgery, University of California , San Francisco, California.,Coleman Memorial Laboratory, University of California , San Francisco, California.,Kavli Institute for Fundamental Neuroscience, University of California , San Francisco, California.,Department of Psychiatry, University of California , San Francisco, California.,Neuroscience Graduate Program, University of California , San Francisco, California
| | - Phillip Larimer
- Center for Integrative Neuroscience, University of California , San Francisco, California.,Coleman Memorial Laboratory, University of California , San Francisco, California.,Department of Neurology, University of California , San Francisco, California
| | - Elizabeth A K Phillips
- Center for Integrative Neuroscience, University of California , San Francisco, California.,Department of Otolaryngology-Head and Neck Surgery, University of California , San Francisco, California.,Coleman Memorial Laboratory, University of California , San Francisco, California.,Neuroscience Graduate Program, University of California , San Francisco, California
| | - Brian J Malone
- Department of Otolaryngology-Head and Neck Surgery, University of California , San Francisco, California.,Coleman Memorial Laboratory, University of California , San Francisco, California.,Kavli Institute for Fundamental Neuroscience, University of California , San Francisco, California
| | - Andrea R Hasenstaub
- Center for Integrative Neuroscience, University of California , San Francisco, California.,Department of Otolaryngology-Head and Neck Surgery, University of California , San Francisco, California.,Coleman Memorial Laboratory, University of California , San Francisco, California.,Kavli Institute for Fundamental Neuroscience, University of California , San Francisco, California
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6
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Dechery JB, MacLean JN. Emergent cortical circuit dynamics contain dense, interwoven ensembles of spike sequences. J Neurophysiol 2017; 118:1914-1925. [PMID: 28724786 DOI: 10.1152/jn.00394.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/05/2017] [Accepted: 07/14/2017] [Indexed: 01/30/2023] Open
Abstract
Temporal codes are theoretically powerful encoding schemes, but their precise form in the neocortex remains unknown in part because of the large number of possible codes and the difficulty in disambiguating informative spikes from statistical noise. A biologically plausible and computationally powerful temporal coding scheme is the Hebbian assembly phase sequence (APS), which predicts reliable propagation of spikes between functionally related assemblies of neurons. Here, we sought to measure the inherent capacity of neocortical networks to produce reliable sequences of spikes, as would be predicted by an APS code. To record microcircuit activity, the scale at which computation is implemented, we used two-photon calcium imaging to densely sample spontaneous activity in murine neocortical networks ex vivo. We show that the population spike histogram is sufficient to produce a spatiotemporal progression of activity across the population. To more comprehensively evaluate the capacity for sequential spiking that cannot be explained by the overall population spiking, we identify statistically significant spike sequences. We found a large repertoire of sequence spikes that collectively comprise the majority of spiking in the circuit. Sequences manifest probabilistically and share neuron membership, resulting in unique ensembles of interwoven sequences characterizing individual spatiotemporal progressions of activity. Distillation of population dynamics into its constituent sequences provides a way to capture trial-to-trial variability and may prove to be a powerful decoding substrate in vivo. Informed by these data, we suggest that the Hebbian APS be reformulated as interwoven sequences with flexible assembly membership due to shared overlapping neurons.NEW & NOTEWORTHY Neocortical computation occurs largely within microcircuits comprised of individual neurons and their connections within small volumes (<500 μm3). We found evidence for a long-postulated temporal code, the Hebbian assembly phase sequence, by identifying repeated and co-occurring sequences of spikes. Variance in population activity across trials was explained in part by the ensemble of active sequences. The presence of interwoven sequences suggests that neuronal assembly structure can be variable and is determined by previous activity.
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Affiliation(s)
- Joseph B Dechery
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois; and
| | - Jason N MacLean
- Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois; and .,Department of Neurobiology, University of Chicago, Illinois
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7
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Cui Z, Wang Q, Gao Y, Wang J, Wang M, Teng P, Guan Y, Zhou J, Li T, Luan G, Li L. Dynamic Correlations between Intrinsic Connectivity and Extrinsic Connectivity of the Auditory Cortex in Humans. Front Hum Neurosci 2017; 11:407. [PMID: 28848415 PMCID: PMC5554526 DOI: 10.3389/fnhum.2017.00407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/25/2017] [Indexed: 12/31/2022] Open
Abstract
The arrival of sound signals in the auditory cortex (AC) triggers both local and inter-regional signal propagations over time up to hundreds of milliseconds and builds up both intrinsic functional connectivity (iFC) and extrinsic functional connectivity (eFC) of the AC. However, interactions between iFC and eFC are largely unknown. Using intracranial stereo-electroencephalographic recordings in people with drug-refractory epilepsy, this study mainly investigated the temporal dynamic of the relationships between iFC and eFC of the AC. The results showed that a Gaussian wideband-noise burst markedly elicited potentials in both the AC and numerous higher-order cortical regions outside the AC (non-auditory cortices). Granger causality analyses revealed that in the earlier time window, iFC of the AC was positively correlated with both eFC from the AC to the inferior temporal gyrus and that to the inferior parietal lobule. While in later periods, the iFC of the AC was positively correlated with eFC from the precentral gyrus to the AC and that from the insula to the AC. In conclusion, dual-directional interactions occur between iFC and eFC of the AC at different time windows following the sound stimulation and may form the foundation underlying various central auditory processes, including auditory sensory memory, object formation, integrations between sensory, perceptional, attentional, motor, emotional, and executive processes.
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Affiliation(s)
- Zhuang Cui
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Beijing HospitalBeijing, China
| | - Qian Wang
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Key Laboratory of Machine Perception (Ministry of Education), Peking UniversityBeijing, China
| | - Yayue Gao
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Key Laboratory of Machine Perception (Ministry of Education), Peking UniversityBeijing, China
| | - Jing Wang
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Mengyang Wang
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Pengfei Teng
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Yuguang Guan
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Jian Zhou
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China
| | - Tianfu Li
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Beijing Institute for Brain DisordersBeijing, China
| | - Guoming Luan
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Department of Functional Neurosurgery, Sanbo Brain Hospital, Capital Medical UniversityBeijing, China.,Beijing Institute for Brain DisordersBeijing, China
| | - Liang Li
- School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Key Laboratory of Machine Perception (Ministry of Education), Peking UniversityBeijing, China.,Beijing Institute for Brain DisordersBeijing, China
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8
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Eggermont JJ, Munguia R, Shaw G. Cross-correlations between three units in cat primary auditory cortex. Hear Res 2013; 304:179-87. [PMID: 23933479 DOI: 10.1016/j.heares.2013.07.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/22/2013] [Accepted: 07/27/2013] [Indexed: 11/25/2022]
Abstract
Here we use a modification of the Joint-Peri-Stimulus-Time histogram (JPSTH) to investigate triple correlations between cat auditory cortex neurons. The modified procedure allowed the decomposition of the xy-pair correlation into a part that is due to the correlation of the x and y units with the trigger unit, and a remaining 'pair correlation'. We analyzed 16 sets of 15-minute duration stationary spontaneous recordings in primary auditory cortex (AI) with between 11 and 14 electrodes from 2 arrays of 8 electrodes each that provided spontaneous firing rates above 0.22 sp/s and for which reliable frequency-tuning curves could be obtained and the characteristic frequency (CF) was estimated. Thus we evaluated 11,282 conditional cross-correlation functions. The predictor for the conditional cross-correlation, calculated on the assumption that the trigger unit had no effect on the xy-pair correlation but using the same fraction of xy spikes, was equal to the conventional pair-wise correlation function between units xy. The conditional correlation of the xy-pair due to correlation of the x and/or y unit with the trigger unit decreased with the geometric mean distance of the xy pair to the trigger unit, but was independent of the pair cross-correlation coefficient. The conditional pair correlation coefficient was estimated at 78% of the measured pair correlation coefficient. Assuming a geometric decreasing effect of activities of units on other electrodes on the conditional correlation, we estimated the potential contribution of a large number of contributing units on the measured pair correlation at 35-50 of that correlation. This suggests that conventionally measured pair correlations in auditory cortex under ketamine anesthesia overestimate the 'true pair correlation', likely resulting from massive common input, by potentially up to a factor 2.
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Affiliation(s)
- Jos J Eggermont
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada; Department of Psychology, University of Calgary, Calgary, Alberta, Canada.
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9
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Detection thresholds for amplitude modulations of tones in budgerigar, rabbit, and human. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 787:391-8. [PMID: 23716245 PMCID: PMC4610919 DOI: 10.1007/978-1-4614-1590-9_43] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Envelope fluctuations of complex sounds carry information that is -essential for many types of discrimination and for detection in noise. To study the neural representation of envelope information and mechanisms for processing of this temporal aspect of sounds, it is useful to identify an animal model that can -sensitively detect amplitude modulations (AM). Low modulation frequencies, which dominate speech sounds, are of particular interest. Yet, most animal -models studied previously are relatively insensitive to AM at low modulation -frequencies. Rabbits have high thresholds for low-frequency modulations, -especially for tone carriers. Rhesus macaques are less sensitive than humans to low-frequency -modulations of wideband noise (O'Conner et al. Hear Res 277, 37-43, 2011). Rats and -chinchilla also have higher thresholds than humans for amplitude -modulations of noise (Kelly et al. J Comp Psychol 120, 98-105, 2006; Henderson et al. J Acoust Soc Am 75, -1177-1183, 1984). In contrast, the budgerigar has thresholds for AM detection of wideband noise similar to those of human listeners at low -modulation frequencies (Dooling and Searcy. Percept Psychophys 46, 65-71, 1981). A -one-interval, two-alternative operant conditioning procedure was used to estimate AM -detection thresholds for 4-kHz tone carriers at low modulation -frequencies (4-256 Hz). Budgerigar thresholds are comparable to those of human subjects in a comparable task. Implications of these comparative results for temporal coding of complex sounds are discussed. Comparative results for masked AM detection are also presented.
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10
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Abstract
We can recognize the melody of a familiar song when it is played on different musical instruments. Similarly, an animal must be able to recognize a warning call whether the caller has a high-pitched female or a lower-pitched male voice, and whether they are sitting in a tree to the left or right. This type of perceptual invariance to "nuisance" parameters comes easily to listeners, but it is unknown whether or how such robust representations of sounds are formed at the level of sensory cortex. In this study, we investigate whether neurons in both core and belt areas of ferret auditory cortex can robustly represent the pitch, formant frequencies, or azimuthal location of artificial vowel sounds while the other two attributes vary. We found that the spike rates of the majority of cortical neurons that are driven by artificial vowels carry robust representations of these features, but the most informative temporal response windows differ from neuron to neuron and across five auditory cortical fields. Furthermore, individual neurons can represent multiple features of sounds unambiguously by independently modulating their spike rates within distinct time windows. Such multiplexing may be critical to identifying sounds that vary along more than one perceptual dimension. Finally, we observed that formant information is encoded in cortex earlier than pitch information, and we show that this time course matches ferrets' behavioral reaction time differences on a change detection task.
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11
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Huetz C, Gourévitch B, Edeline JM. Neural codes in the thalamocortical auditory system: from artificial stimuli to communication sounds. Hear Res 2010; 271:147-58. [PMID: 20116422 DOI: 10.1016/j.heares.2010.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/22/2010] [Accepted: 01/22/2010] [Indexed: 10/19/2022]
Abstract
Over the last 15 years, an increasing number of studies have described the responsiveness of thalamic and cortical neurons to communication sounds. Whereas initial studies have simply looked for neurons exhibiting higher firing rate to conspecific vocalizations over their modified, artificially synthesized versions, more recent studies determine the relative contribution of "rate coding" and "temporal coding" to the information transmitted by spike trains. In this article, we aim at reviewing the different strategies employed by thalamic and cortical neurons to encode information about acoustic stimuli, from artificial to natural sounds. Considering data obtained with simple stimuli, we first illustrate that different facets of temporal code, ranging from a strict correspondence between spike-timing and stimulus temporal features to more complex coding strategies, do already exist with artificial stimuli. We then review lines of evidence indicating that spike-timing provides an efficient code for discriminating communication sounds from thalamus, primary and non-primary auditory cortex up to frontal areas. As the neural code probably developed, and became specialized, over evolution to allow precise and reliable processing of sounds that are of survival value, we argue that spike-timing based coding strategies might set the foundations of our perceptive abilities.
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Affiliation(s)
- Chloé Huetz
- Centre de Neurosciences Paris Sud, UMR CNRS 8195, Université Paris-Sud, 91405 Orsay Cedex, France
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