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Temporally dynamic frequency tuning of population responses in monkey primary auditory cortex

HEARING RESEARCH 2009年第1-2期254卷 64-76页

作者： Fishman, Yonatan I. Steinschneider, Mitchell Albert Einstein Coll Med Rose F Kennedy Ctr Dept Neurol Bronx NY 10461 USA Albert Einstein Coll Med Rose F Kennedy Ctr Dept Neurosci Bronx NY 10461 USA

Frequency tuning of auditory cortical neurons is typically determined by integrating spikes over the entire duration of a tone stimulus. However, this approach may mask functionally significant variations in tuning over the time course of the response. To explore this possibility, frequency response functions (FRFs) based on population multiunit activity evoked by pure tones of 175 or 200 ms duration were examined within four time windows relative to stimulus onset corresponding to "on" (10-30 ms), "early sustained" (30-100 ms), "late sustained" (100-175 ms), and "off" (185-235 or 210-260 ms) portions of responses in primary auditory cortex (A1) of 5 awake macaques. FRFs of "on" and "early sustained" responses displayed a good concordance, with best frequencies (BFs) differing, on average, by less than 0.25 octaves. In contrast, FRFs of "on" and "late sustained" responses differed considerably, with a mean difference in BF of 0.68 octaves. At many sites, tuning of "off' responses was inversely related to that of "on" responses, with "off" FRFs displaying a trough at the BF of "on" responses. Inversely correlated "on" and "off' FRFs were more common at sites with a higher "on" BF, thus suggesting functional differences between sites with low and high "on" BF. These results indicate that frequency tuning of population responses in A1 may vary considerably over the course of the response to a tone, thus revealing a temporal dimension to the representation of sound spectrum in A1. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Auditory cortex Spectral tuning Tonotopic organization Onset response Sustained response Off response population coding

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Numerical study of short-term afterimages and associate properties in foveal vision

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VISION RESEARCH 2006年第3期46卷 365-381页

作者： Momiji, H Bharath, AA Hankins, MW Kennard, C Univ London Imperial Coll Sci Technol & Med Dept Bioengn London SW7 2AZ England Univ London Imperial Coll Sci Technol & Med Div Neurosci & Mental Hlth Dept Visual Neurosci London W6 8RP England

A cellular model of the primate retina has been developed. Unlike existing models, it incorporates spatial non-uniformities, such as the random arrangement of L and M cones, and the radial dilation with eccentricity. Based on a population of ganglion cell activities, colour-image representation is modelled with the luminance and the R-G opponent channels. The developed model reproduces experimentally known properties in temporal and spatial vision. Furthermore, spatio-temporally coupled properties such as transition from positive to negative phases in an afterimage, are recapped. In colour vision, the model can explain the insensitivity in our colour perception to the L/M cone ratio. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： mathematical model fovea afterimage colour population coding

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A multielectrode implant device for the cerebral cortex

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JOURNAL OF NEUROSCIENCE METHODS 1999年第1期93卷 27-35页

作者： deCharms, RC Blake, DT Merzenich, MM Univ Calif San Francisco Coleman Lab San Francisco CA 94143 USA Univ Calif San Francisco Keck Ctr Integrat Neurosci San Francisco CA 94143 USA

A new class of brain implant technology was developed that allows the simultaneous recording of voltage signals from many individual neurons in the cerebral cortex during cognitive tasks. The device allows recording from 49 independent positions spanning a 2 x 2-mm region of neural tissue. The recording electrodes are positioned in a square grid with 350 mu m spacing, and each microelectrode can be precisely independently vertically positioned using a hydraulic microdrive. The device utilizes ultrafine, sharp iridium microelectrodes that minimize mechanical disturbance of the region near the electrode tip and produce low noise neuronal recordings. The total weight of this device is less than 20 g, and the device is reusable. The implant device has been used for transdural recordings in primary somatosensory and auditory cortices of marmosets, owl monkeys, and rats. On a typical day, one-third of the microelectrodes yield well-discriminated single neuron action potential waveforms. Additional array electrodes yield lower amplitude driven multiunit activity. The average signal-to-noise ratio of discriminated action potential waveforms 6 months after implantation was greater than 9. Simple design alternatives are discussed that can increase the number of electrodes in the array and the depths at which dense array recordings can be achieved. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： array auditory behavior population coding primate somatosensory

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Signal detection theory, uncertainty, and Poisson-like population codes

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VISION RESEARCH 2010年第22期50卷 2308-2319页

作者： Ma, Wei Ji Baylor Coll Med Houston TX 77030 USA

The juxtaposition of established signal detection theory models of perception and more recent claims about the encoding of uncertainty in perception is a rich source of confusion Are the latter simply a rehash of the former? Here we make an attempt to distinguish precisely between optimal and probabilistic computation In optimal computation the observer minimizes the expected cost under a posterior probability distribution In probabilistic computation the observer uses higher moments of the likelihood function of the stimulus on a trial-by trial basis Computation can be optimal without being probabilistic and vice versa Most signal detection theory models describe optimal computation Behavioral data only provide evidence for a neural representation of uncertainty if they are best described by a model of probabilistic computation We argue that single-neuron activity sometimes suffices for optimal computation but never for probabilistic computation A population code is needed instead Not every population code is equally suitable because nuisance parameters have to be marginalized out This problem is solved by Poisson-like but not by Gaussian variability Finally we build a dictionary between signal detection theory quantities and Poisson like population quantities (C) 2010 Elsevier Ltd All rights reserved

关键词： Signal detection theory population coding Bayesian inference Single neurons

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Strongly directional responses to tones and conspecific calls in the auditory nerve of the Tokay gecko, Gekko gecko

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JOURNAL OF NEUROPHYSIOLOGY 2021年第3期125卷 887-902页

作者： Christensen-Dalsgaard, Jakob Kuokkanen, Paula Matthews, Jamie Emoto Carr, Catherine E. Univ Southern Denmark Dept Biol Odense Denmark Humboldt Univ Inst Theoret Biol Dept Biol Berlin Germany Univ Maryland Dept Biol College Pk MD 20742 USA

The configuration of lizard ears, where sound can reach both surfaces of the eardrums, produces a strongly directional ear, but the subsequent processing of sound direction by the auditory pathway is unknown. We report here on directional responses from the first stage, the auditory nerve. We used laser vibrometry to measure eardrum responses in Tokay geckos and in the same animals recorded 117 auditory nerve single fiber responses to free-field sound from radially distributed speakers. Responses from all fibers showed strongly lateralized activity at all frequencies, with an ovoidal directivity that resembled the eardrum directivity. Geckos are vocal and showed pronounced nerve fiber directionality to components of the call. To estimate the accuracy with which a gecko could discriminate between sound sources, we computed the Fisher information (FI) for each neuron. FI was highest just contralateral to the midline, front and back. Thus, the auditory nerve could provide a population code for sound source direction, and geckos should have a high capacity to differentiate between midline sound sources. In brain, binaural comparisons, for example, by IE (ipsilateral excitatory, contralateral inhibitory) neurons, should sharpen the lateralized responses and extend the dynamic range of directionality. NEW & NOTEWORTHY In mammals, the two ears are unconnected pressure receivers, and sound direction is computed from binaural interactions in the brain, but in lizards, the eardrums interact acoustically, producing a strongly directional response. We show strongly lateralized responses from gecko auditory nerve fibers to directional sound stimulation and high Fisher information on either side of the midline. Thus, already the auditory nerve provides a population code for sound source direction in the gecko.

关键词： hearing lizard middle ear population coding sound localization

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A METHOD OF ORGANIZATION OF A PARALLEL-HIERARCHICAL NETWORK FOR IMAGE RECOGNITION

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CYBERNETICS AND SYSTEMS ANALYSIS 2011年第1期47卷 140-151页

作者： Timchenko, L. I. Melnikov, V. V. Kokryatskaya, N. I. Kutaev, Y. F. Ivasyukd, I. D. State Econ Technol Transport Univ Kiev Ukraine Vinnytsya Natl Tech Univ Vinnytsya Ukraine Spa Astrophys Moscow Russia Vinnytsya Reg State Adm Board Educ Vinnytsya Ukraine

A method of parallel-hierarchical transformation based on population coding is described and the use of this method for image recognition is considered. This parallel-hierarchical transformation is described as a system model for image recognition. Theoretical information, experimental investigations, and a software realization are presented.

关键词： parallel-hierarchical network population coding image preparation correlation comparison pattern of laser beam spots man face image

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Odor-evoked activity is spatially distributed in piriform cortex

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JOURNAL OF COMPARATIVE NEUROLOGY 2003年第4期457卷 361-373页

作者： Illig, KR Haberly, LB Univ Wisconsin Dept Anat Madison WI 53706 USA Univ Wisconsin Ctr Neurosci Madison WI 53706 USA

Much data on the olfactory bulb (OB) indicates that structural characteristics of odorant molecules are encoded as ordered, spatially consolidated sets of active cells. New results with "genetic tracing" (Zou et al. [2001] Nature 414:173-1.79) suggest that spatial order is also present in projections from the OB to the olfactory cortex. For the piriform cortex (PC), results with this technique indicate that afferents conveying input derived from single olfactory receptors (ORs) are distributed to well-defined patches in the anterior PC (APC) but that these patches are much larger than in the OB. We have used c-fos induction to examine how input patterning for single ORs is translated into patterns of odor-evoked cellular activity in the PC. The laminar distribution of labeled cells and dual-immunostaining for gamma-aminobutyric acid (GABA)ergic markers indicated that activity was detected largely in pyramidal cells. In odor-stimulated rats, labeled cells were present throughout the posterior PC (PPC) but were concentrated in prominent rostrocaudal bands in APC. Analysis of responses to different odorants and concentrations revealed that locations and shapes of bands conveyed no apparent information regarding odor quality, rather, they appeared to correspond to subregions of the APC distinguished by cytoarchitecture and connectivity. Small-scale variations in labeling density were observed within APC bands and throughout the PPC that could reflect the presence of a complex topographical order, but discrete patches at consistent locations as observed by genetic tracing were absent. This finding suggests that as a result of afferent overlap and intracortical. processing, odor-quality information is represented by spatially distributed sets of cells. A distributed organization may be optimal for discriminating biologically relevant odorants that activate large numbers of ORs.

关键词： olfactory cortex olfaction c-fos Fos population coding spatial organization

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Comparative computations of spike synchronization in visual cortex of cats

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BRAIN RESEARCH PROTOCOLS 2001年第3期6卷 148-158页

作者： Molotchnikoff, S Aïtoubah, J Bretzner, F Shumikhina, S Tan, YF Guillemot, JP Univ Montreal Dept Sci Biol Montreal PQ H3C 3J7 Canada Univ Montreal Dept Psychol Montreal PQ H3C 3J7 Canada

In recent years it has been proposed that synchronous activity between neurons is a putative mechanism to bind together various trigger features of an image. Thus the: measure of synchronization becomes an important issue since it may be an electrophysiological sign of visual perception. This paper describes: and compares six techniques of computing synchronization strength, that is, the central peak of a coss-correlogram, Data were obtained in anesthetized cats prepared for electrophysiological recordings in a conventional fashion. Results indicate that: (1) eye fits are misleading. Visual inspection of cross-correlograms, may be interesting if one needs to estimate approximately synchronization strength and the presence of oscillations in the cross-correlograms, however it may be misleading if one wants to compare different cross-correlograms;(2) regression analysis to compare one method against the others yields a relatively poor correlation suggesting that methods are not directly comparable;(3) the sensitivity of each computational method is unequal. The results may indicate that som functional connections are either under- or over-evaluated depending upon the strategy employed to measure synchronization. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： neuronal synchronization visual cortex correlation analysis temporal binding population coding

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A Stable Visual World in Primate Primary Visual Cortex

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CURRENT BIOLOGY 2019年第9期29卷 1471-+页

作者： Morris, Adam P. Krekelberg, Bart Monash Univ Dept Physiol Neurosci Program Biomed Discovery Inst 26 Innovat Walk Clayton Vic 3800 Australia Rutgers State Univ Ctr Mol & Behav Neurosci 197 Univ Ave Newark NJ 07102 USA

Humans and other primates rely on eye movements to explore visual scenes and to track moving objects. As a result, the image that is projected onto the retina-and propagated throughout the visual cortical hierarchy-is almost constantly changing and makes little sense without taking into account the momentary direction of gaze. How is this achieved in the visual system? Here, we show that in primary visual cortex (V1), the earliest stage of cortical vision, neural representations carry an embedded "eye tracker" that signals the direction of gaze associated with each image. Using chronically implanted multi-electrode arrays, we recorded the activity of neurons in area V1 of macaque monkeys during tasks requiring fast (exploratory) and slow (pursuit) eye movements. Neurons were stimulated with flickering, full-field luminance noise at all times. As in previous studies, we observed neurons that were sensitive to gaze direction during fixation, despite comparable stimulation of their receptive fields. We trained a decoder to translate neural activity into metric estimates of gaze direction. This decoded signal tracked the eye accurately not only during fixation but also during fast and slow eye movements. After a fast eye movement, the eye-position signal arrived in V1 at approximately the same time at which the new visual information arrived from the retina. Using simulations, we show that this V1 eye-position signal could be used to take into account the sensory consequences of eye movements and map the fleeting positions of objects on the retina onto their stable position in the world.

关键词： vision primary visual cortex electrophysiology eye position population coding computation

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Multi-dimensional coding by Basolateral Amygdala Neurons

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NEURON 2018年第6期99卷 1315-+页

作者： Kyriazi, Pinelopi Headley, Drew B. Pare, Denis Rutgers State Univ Behav & Neural Sci Grad Program Newark NJ 07102 USA Rutgers State Univ Ctr Mol & Behav Neurosci Newark NJ 07102 USA

Conditioned appetitive and aversive responses (CRs) are thought to result from the activation of specific subsets of valence-coding basolateral amygdala (BLA) neurons. Under this model, the responses of BLA cells to conditioned stimuli (CSs) and the activity that drives CRs are closely related. We tested the strength of this correlation using a task where rats could emit different CRs in response to the same CSs. At odds with this model, the CS responses and CR-related activity of individual BLA cells were separable. Moreover, while the incidence of valence-coding cells did not exceed chance, at the population level there was similarity between valence coding for CSs and CRs. In fact, both lateral and basolateral neurons concurrently encoded multiple task features and behaviors. Thus, conditioned emotional behaviors may not depend on the recruitment of single cells that explicitly encode individual task variables but from multiplexed representations distributed across the BLA.

关键词： amygdala valence population coding conditioning reward punishment

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