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Decoding sound level in the marmoset primary auditory cortex

JOURNAL OF NEUROPHYSIOLOGY 2017年第4期118卷 2024-2033页

作者： Sun, Wensheng Marongelli, Ellisha N. Watkins, Paul V. Barbour, Dennis L. Washington Univ Dept Biomed Engn One Brookings Dr St Louis MO 63130 USA

Neurons that respond favorably to a particular sound level have been observed throughout the central auditory system, becoming steadily more common at higher processing areas. One theory about the role of these level-tuned or nonmonotonic neurons is the level-invariant encoding of sounds. To investigate this theory, we simulated various subpopulations of neurons by drawing from real primary auditory cortex (A1) neuron responses and surveyed their performance in forming different sound level representations. Pure nonmonotonic subpopulations did not provide the best level-invariant decoding;instead, mixtures of monotonic and nonmonotonic neurons provided the most accurate decoding. For level-fidelity decoding, the inclusion of nonmonotonic neurons slightly improved or did not change decoding accuracy until they constituted a high proportion. These results indicate that nonmonotonic neurons fill an encoding role complementary to, rather than alternate to, monotonic neurons. NEW & NOTEWORTHY Neurons with nonmonotonic rate-level functions are unique to the central auditory system. These level-tuned neurons have been proposed to account for invariant sound perception across sound levels. Through systematic simulations based on real neuron responses, this study shows that neuron populations perform sound encoding optimally when containing both monotonic and nonmonotonic neurons. The results indicate that instead of working independently, nonmonotonic neurons complement the function of monotonic neurons in different sound-encoding contexts.

关键词： primate auditory cortex neural coding sound pressure level encoding nonmonotonic

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Dynamical basis of irregular spiking in NMDA-driven prefrontal cortex neurons

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CEREBRAL CORTEX 2007年第4期17卷 894-908页

作者： Durstewitz, Daniel Gabriel, Thomas Univ Plymouth Ctr Theoret & Computat Neurosci Plymouth PL4 8AA Devon England

Slow N-Methyl-D-aspartic acid (NMDA) synaptic currents are assumed to strongly contribute to the persistently elevated firing rates observed in prefrontal cortex (PFC) during working memory. During persistent activity, spiking of many neurons is highly irregular. Here we report that highly irregular firing can be induced through a combination of NMDA- and dopamine D1 receptor agonists applied to adult PFC neurons in vitro. The highest interspike-interval (ISI) variability occurred in a transition regime where the subthreshold membrane potential distribution shifts from mono- to bimodality, while neurons with clearly mono- or bimodal distributions fired much more regularly. Predictability within irregular ISI series was significantly higher than expected from a noise-driven linear process, indicating that it might best be described through complex (potentially chaotic) nonlinear deterministic processes. Accordingly, the phenomena observed in vitro could be reproduced in purely deterministic biophysical model neurons. High spiking irregularity in these models emerged within a chaotic, close-to-bifurcation regime characterized by a shift of the membrane potential distribution from mono- to bimodality and by similar ISI return maps as observed in vitro. The nonlinearity of NMDA conductances was crucial for inducing this regime. NMDA-induced irregular dynamics may have important implications for computational processes during working memory and neural coding.

关键词： chaos neural coding computation bursting slice electrophysiology biophysical model

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Efficient inhibition of bursts by bursts in the auditory system of crickets

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JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY neural AND BEHAVIORAL PHYSIOLOGY 2007年第6期193卷 625-633页

作者： Marsat, G. Pollack, G. S. McGill Univ Dept Biol Montreal PQ H3A 1B1 Canada

In crickets, auditory information about ultrasound is carried bilaterally to the brain by the AN2 neurons. The ON1 neuron provides contralateral inhibitory input to AN2, thereby enhancing bilateral contrast between the left and right AN2s, an important cue for sound localization. We examine how the structures of the spike trains of these neurons affect this inhibitory interaction. As previously shown for AN2, ON1 responds to salient peaks in stimulus amplitude with bursts of spikes. Spike bursts, but not isolated spikes, reliably signal the occurrence of specific features of the stimulus. ON1 and AN2 burst at similar times relative to the amplitude envelope of the stimulus, and bursts are more tightly time-locked to stimulus feature than the isolated spikes. As a consequence, spikes that, in the absence of contralateral inhibition, would occur within AN2 bursts are more likely to be preceded by spikes in ON1 (mainly also in bursts) than are isolated AN2 spikes. This leads to a large decrease in the burst rate of the inhibited AN2. We conclude that the match in coding properties of ON1 and AN2 allows contralateral inhibition to be most efficient for those portions of the response that carry the behaviourally relevant information, i.e. for bursts.

关键词： sound localization neural coding bat evasion feature detection temporal pattern

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Neuron-Specific Stimulus Masking Reveals Interference in Spike Timing at the Cortical Level

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JARO-JOURNAL OF THE ASSOCIATION FOR RESEARCH IN OTOLARYNGOLOGY 2012年第1期13卷 81-89页

作者： Larson, Eric Maddox, Ross K. Perrone, Ben P. Sen, Kamal Billimoria, Cyrus P. Boston Univ Dept Biomed Engn Hearing Res Ctr Boston MA 02215 USA Boston Univ Ctr Biodynam Boston MA 02215 USA

The auditory system is capable of robust recognition of sounds in the presence of competing maskers (e.g., other voices or background music). This capability arises despite the fact that masking stimuli can disrupt neural responses at the cortical level. Since the origins of such interference effects remain unknown, in this study, we work to identify and quantify neural interference effects that originate due to masking occurring within and outside receptive fields of neurons. We record from single and multi-unit auditory sites from field L, the auditory cortex homologue in zebra finches. We use a novel method called spike timing-based stimulus filtering that uses the measured response of each neuron to create an individualized stimulus set. In contrast to previous adaptive experimental approaches, which have typically focused on the average firing rate, this method uses the complete pattern of neural responses, including spike timing information, in the calculation of the receptive field. When we generate and present novel stimuli for each neuron that mask the regions within the receptive field, we find that the time-varying information in the neural responses is disrupted, degrading neural discrimination performance and decreasing spike timing reliability and sparseness. We also find that, while removing stimulus energy from frequency regions outside the receptive field does not significantly affect neural responses for many sites, adding a masker in these frequency regions can nonetheless have a significant impact on neural responses and discriminability without a significant change in the average firing rate. These findings suggest that maskers can interfere with neural responses by disrupting stimulus timing information with power either within or outside the receptive fields of neurons.

关键词： masking birdsong auditory cortex spectrotemporal receptive field neural coding

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What can spike train distances tell us about the neural code?

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JOURNAL OF NEUROSCIENCE METHODS 2011年第1期199卷 146-165页

作者： Chicharro, Daniel Kreuz, Thomas Andrzejak, Ralph G. Univ Pompeu Fabra Dept Informat & Commun Technol Barcelona Spain Univ Calif San Diego Inst Nonlinear Sci La Jolla CA 92093 USA CNR Inst Complex Syst Sesto Fiorentino Italy

Time scale parametric spike train distances like the Victor and the van Rossum distances are often applied to study the neural code based on neural stimuli discrimination. Different neural coding hypotheses, such as rate or coincidence coding, can be assessed by combining a time scale parametric spike train distance with a classifier in order to obtain the optimal discrimination performance. The time scale for which the responses to different stimuli are distinguished best is assumed to be the discriminative precision of the neural code. The relevance of temporal coding is evaluated by comparing the optimal discrimination performance with the one achieved when assuming a rate code. We here characterize the measures quantifying the discrimination performance, the discriminative precision, and the relevance of temporal coding. Furthermore, we evaluate the information these quantities provide about the neural code. We show that the discriminative precision is too unspecific to be interpreted in terms of the time scales relevant for encoding. Accordingly, the time scale parametric nature of the distances is mainly an advantage because it allows maximizing the discrimination performance across a whole set of measures with different sensitivities determined by the time scale parameter, but not due to the possibility to examine the temporal properties of the neural code. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Spike trains Spike train distances Discrimination Mutual information Precision Temporal coding neural coding

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Decoding first-spike latency: A likelihood approach

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NEUROCOMPUTING 2001年 38卷 239-248页

作者： Jenison, RL Univ Wisconsin Dept Psychol Madison WI 53706 USA

First-spike latency at the level of auditory cortex appears to correlate well with sound source direction. However, an unsettled issue with latency as a neural code is the apparent lack of temporal marking for the onset of the stimulus. One possible resolution is that relative ensemble latencies could be decoded rather than absolute latencies. How an ensemble timing referent might inform a theoretical ideal observer remains largely unexplored. A likelihood approach is derived for decoding sound direction from a sample population of cortical neurons in cat auditory cortex based on relative first-spike latencies, and is evaluated using Fisher information. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： neural coding first-spike latency likelihood fisher information sound localization

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A new correlation-based measure of spike timing reliability

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NEUROCOMPUTING 2003年第1期52-4卷 925-931页

作者： Schreiber, S Fellous, JM Whitmer, D Tiesinga, P Sejnowski, TJ Salk Inst Biol Studies Sloan Swartz Ctr Theoret Neurobiol La Jolla CA 92037 USA Salk Inst Biol Studies Computat Neurosci Lab La Jolla CA 92037 USA Salk Inst Biol Studies Howard Hughes Med Inst Computat Neurobiol Lab La Jolla CA 92037 USA Univ Calif San Diego Dept Biol La Jolla CA 92093 USA Univ N Carolina Dept Phys & Astron Chapel Hill NC 27599 USA

We introduce a new correlation-based measure of spike timing reliability. Unlike other measures, it does not require the definition of a posteriori "events". It relies on only one parameter, which relates to the timescale of spike timing precision. We test the measure on Surrogate data sets with varying amounts of spike time jitter, and missing or additional spikes, and compare it with a widely used histogram-based measure. The measure is efficient and faithful in characterizing spike timing reliability and produces smaller errors in the reliability estimate than the histogram-based measure based on the same number of trials. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： spike timing reliability correlation-based measure precision neural coding

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Modelling spatiotemporal olfactory data in two steps: from binary to Hodgkin-Huxley neurones

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BIOSYSTEMS 2002年第1-3期67卷 203-211页

作者： Quenet, B Dubois, R Sirapian, S Dreyfus, G Horn, D Ecole Super Phys & Chim Ind Ville Paris Elect Lab F-75005 Paris France Tel Aviv Univ Sch Phys & Astron IL-69978 Tel Aviv Israel

Network models of synchronously updated McCulloch-Pitts neurones exhibit complex spatiotemporal patterns that are similar to activities of biological neurones in phase with a periodic local field potential, such as those observed experimentally by Wehr and Laurent (1996, Nature 384, 162-166) in the locust olfactory pathway. Modelling biological neural nets with networks of simple formal units makes the dynamics of the model analytically tractable. It is thus possible to determine the constraints that must be satisfied by its connection matrix in order to make its neurones exhibit a given sequence of activity (see, for instance, Quenet et at., 2001, Neurocomputing 38-40, 831-836). In the present paper, we address the following question: how can one construct a formal network of Hodgkin-Huxley (HH) type neurotics that reproduces experimentally observed neuronal codes? A two-step strategy is suggested in the present paper: first, a simple network of binary units is designed, whose activity reproduces the binary experimental codes;second, this model is used as a guide to design a network of more realistic formal HH neurones. We show that such a strategy is indeed fruitful: it allowed us to design a model that reproduces the Wehr-Laurent olfactory codes, and to investigate the robustness of these codes to synaptic noise. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

关键词： neural coding olfactory system spatiotemporal patterns Hodgkin-Huxley model formal neural network Hopfield-Little dynamics

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RAPIDLY AND SLOWLY ADAPTING MECHANORECEPTORS IN THE GLANS-PENIS OF THE CAT

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PHYSIOLOGY & BEHAVIOR 1986年第1期37卷 69-78页

作者： JOHNSON, RD KITCHELL, RL GILANPOUR, H UNIV CALIF DAVIS SCH VET MED DEPT ANAT DAVIS CA 95616 USA

Sixty-one single mechanoreceptive fibers were surgically isolated from the dorsal nerve of the penis in anesthetized, mature, and sexually intact male cats. Impulse activity was recorded extracellularly. Receptive fields on the glans penis were stimulated with an accurate computer controlled mechanostimulator. Thirty-four units were categorized as rapidly adapting (RA) based on the absence of a response to sustained skin displacement. The remaining were slowly adapting (SA) units responding to sustained displacement. Most of the SA units were located in the distal smooth glans whereas RA units predominated in the proximal spiny glans. Displacement thresholds were significantly lower for RA units. All units encoded indentation velocity although the SA units were better suited to discriminate slowly moving stimuli. In addition, SA units encoded sustained displacement amplitude. Male cats with a denervated glans penis display disoriented mounting behavior disabling intromission. The presence of distally located SA mechanoreceptors suggests they may be the primary penile proprioceptors, mediating, along with the RA mechanoreceptors, successful completion of intromission.

关键词： Mechanoreceptors Glans penis Single unit recording neural coding Cat

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ELECTROPHYSIOLOGICAL CORRELATES OF FLICKER PERCEPTION IN CAT

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PHYSIOLOGY & BEHAVIOR 1972年第4期8卷 603-&页

作者： SCHWARTZ, AS Division of Neurobiology Barrow Neurological Institute of St. Joseph's Hospital and Medical Center Phoenix Arizona U.S.A.

The roles of the geniculostriate system and the superior colliculus in determining the critical flicker frequency (CFF) in cats were studied by subtotal lesions and electrical recordings in these respective areas. Lesions in the former uniformly decreased CFF; lesions in the latter usually were followed by increased CFF, which could have been due to continued training. These results suggested that the geniculostriate system mediated high frequencies of flicker, while the colliculus could mediate only lower frequencies. Photic following activity, defined as time-integrated power measurements of the fundamental flicker frequencies in the EEGs of these two areas, occurred reliably at suprathreshold frequencies in the cortex and at much lower frequencies in the colliculus. A quantitative relationship between CFF and photic following activity by these visual mechanisms was also noted. The data further support the view that the function of these visual components in the determination of CFF in the intact cat differ, and suggest the possibility that the colliculus may serve as a filter to limit the the discrimination of high flicker rates.

关键词： Critical flicker frequency neural coding EEG Photic following Visual mechanisms

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