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Object decoding with attention in inferior temporal cortex

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2011年第21期108卷 8850-8855页

作者： Zhang, Ying Meyers, Ethan M. Bichot, Narcisse P. Serre, Thomas Poggio, Tomaso A. Desimone, Robert MIT Dept Brain & Cognit Sci McGovern Inst Cambridge MA 02139 USA Brown Univ Dept Cognit Linguist & Psychol Sci Providence RI 02912 USA

Recognizing objects in cluttered scenes requires attentional mechanisms to filter out distracting information. Previous studies have found several physiological correlates of attention in visual cortex, including larger responses for attended objects. However, it has been unclear whether these attention-related changes have a large impact on information about objects at the neural population level. To address this question, we trained monkeys to covertly deploy their visual attention from a central fixation point to one of three objects displayed in the periphery, and we decoded information about the identity and position of the objects from populations of similar to 200 neurons from the inferior temporal cortex using a pattern classifier. The results show that before attention was deployed, information about the identity and position of each object was greatly reduced relative to when these objects were shown in isolation. However, when a monkey attended to an object, the pattern of neural activity, represented as a vector with dimensionality equal to the size of the neural population, was restored toward the vector representing the isolated object. Despite this nearly exclusive representation of the attended object, an increase in the salience of nonattended objects caused "bottom-up" mechanisms to override these "top-down" attentional enhancements. The method described here can be used to assess which attention-related physiological changes are directly related to object recognition, and should be helpful in assessing the role of additional physiological changes in the future.

关键词： macaque vision readout population coding neural coding

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Recruitment strategies in efferent sympathetic nerve activity

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CLINICAL AUTONOMIC RESEARCH 2017年第6期27卷 369-378页

作者： Shoemaker, J. Kevin Univ Western Ontario Sch Kinesiol Room 3159C Thames Hall1151 Richmond St N London ON N6A 3K7 Canada

In 1968, the first reported microneurographic recordings of muscle sympathetic nerve activity (MSNA) in humans revealed the bursty behavior of efferent sympathetic nerve activity. The timing of bursts could be explained by baroreflex physiology, but the variability in size of each burst was left unexplained. On the basis of shorter latencies of larger bursts, Wallin's group [53] proposed the existence of variable supraspinal synaptic delays and/or options for recruitment of faster-conducting sympathetic neurons when bursts become stronger. These options represent features of recruitable neural systems. Based on the highly variable latencies of single axons whose firing patterns could not explain reflexive increases in burst size, the concept of a latent subpopulation of sympathetic axons was speculated to exist. Using evidence from experimental preparations in anesthetized smaller animals, to recent signal processing of multi-fiber recordings in humans, this brief review will discuss the attempts to discover and understand recruitment strategies within the peripheral sympathetic nervous system. The review focuses on new information from human recordings supporting the idea that rate coding, population coding (recruitment), and temporal coding are options available within the peripheral sympathetic nervous system to adjust efferent sympathetic outflow. Although data are limited, possible clinical applications are discussed.

关键词： MSNA Action potentials population coding Rate coding Microneurography

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A simple linear readout of MT supports motion direction-discrimination performance

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JOURNAL OF NEUROPHYSIOLOGY 2020年第2期123卷 682-694页

作者： Yates, Jacob L. Katz, Leor N. Levi, Aaron J. Pillow, Jonathan W. Huk, Alexander C. Univ Rochester Brain & Cognit Sci Rochester NY 14627 USA Univ Texas Austin Ctr Perceptual Syst Austin TX 78712 USA Univ Texas Austin Dept Neurosci Austin TX 78712 USA NEI Lab Sensorimotor Res NIH Bethesda MD 20892 USA Princeton Univ Princeton Neurosci Inst Princeton NJ 08544 USA Princeton Univ Dept Psychol Princeton NJ 08544 USA Univ Texas Austin Dept Psychol Austin TX 78712 USA

Motion discrimination is a well-established model system for investigating how sensory signals are used to form perceptual decisions. Classic studies relating single-neuron activity in the middle temporal area (MT) to perceptual decisions have suggested that a simple linear readout could underlie motion discrimination behavior. A theoretically optimal readout, in contrast. would take into account the correlations between neurons and the sensitivity of individual neurons at each time point. IIowever, it remains unknown how sophisticated the readout needs to be to support actual motion-discrimination behavior or to approach optimal performance. In this study, we evaluated the performance of various neurally plausible decoders. trained to discriminate motion direction from small ensembles of simultaneously recorded MT neurons. We found that decoding the stimulus without knowledge of the interneuronal correlations was sufficient to match an optimal (correlation aware) decoder. Additionally, a decoder could match the psychophysical performance of the animals with flat integration of up to half the stimulus and inherited temporal dynamics from the time-varying MT responses. These results demonstrate that simple, linear decoders operating on small ensembles of neurons can match both psychophysical performance and optimal sensitivity without taking correlations into account and that such simple read-out mechanisms can exhibit complex temporal properties inherited from the sensory dynamics themselves. NEW & NOTEWORTHY Motion perception depends on the ability to decode the activity of neurons in the middle temporal area. Theoretically optimal decoding requires knowledge of the sensitivity of neurons and interneuronal correlations. We report that a simple correlation-blind decoder performs as well as the optimal decoder for coarse motion discrimination. Additionally. the decoder could match the psychophysical performance with moderate temporal integration and dynamics inherite

关键词： MT perceptual decision making population coding visual motion

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Decoding of Attentional State Using High-Frequency Local Field Potential Is As Accurate As Using Spikes

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CEREBRAL CORTEX 2021年第9期31卷 4314-4328页

作者： Prakash, Surya S. Das, Aritra Kanth, Sidrat Tasawoor Mayo, J. Patrick Ray, Supratim Indian Inst Sci Ctr Neurosci Old TIFR Bldg Bangalore 560012 Karnataka India Indian Inst Sci IISc Math Initiat Bangalore 560012 Karnataka India Univ Pittsburgh Dept Ophthalmol Pittsburgh PA 15213 USA

Local field potentials (LFPs) in visual cortex are reliably modulated when the subject's focus of attention is cued into versus out of the receptive field of the recorded sites, similar to modulation of spikes. However, human psychophysics studies have used an additional attention condition, neutral cueing, for decades. The effect of neutral cueing on spikes was examined recently and found to be intermediate between cued and uncued conditions. However, whether LFPs are also precise enough to represent graded states of attention is unknown. We found in rhesus monkeys that LFPs during neutral cueing were also intermediate between cued and uncued conditions. For a single electrode, attention was more discriminable using high frequency (>30 Hz) LFP power than spikes, which is expected because LFP represents a population signal and therefore is expected to be less noisy than spikes. However, previous studies have shown that when multiple electrodes are used, spikes can outperform LFPs. Surprisingly, in our study, spikes did not outperform LFPs when discriminability was computed using multiple electrodes, even though the LFP activity was highly correlated across electrodes compared with spikes. These results constrain the spatial scale over which attention operates and highlight the usefulness of LFPs in studying attention.

关键词： gamma high-gamma linear discriminant analysis population coding spatial attention

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Fast rate coding in hippocampal CA3 cell ensembles

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HIPPOCAMPUS 2006年第9期16卷 765-774页

作者： Leutgeb, Stefan Leutgeb, Jill K. Moser, Edvard I. Moser, May-Britt Norwegian Univ Sci & Technol Ctr Biol Memory N-7489 Trondheim Norway

Environments with overlapping features are represented by distinct patterns of activity in the hippocampus, enabling information to be stored and retrieved with minimal interference. This orthogonalization of correlated inputs is thought to take place within the hippocampus itself. However, the orthogonalization process has been shown to take days to develop in CA1. This prolonged time course is in striking contrast to the fast encoding of behavioral memory by the hippocampus. To explore this apparent paradox, we asked whether orthogonalization depended on the type of remapping exhibited by the hippocampal network. We have previously distinguished two types of remapping, global remapping, which results in the activation of different assemblies of place fields, and rate remapping, which encodes differences between cue constellations by substantial changes in firing rate without a change in the place code. Global remapping has previously been shown to be expressed immediately at novel locations. Here we asked if rate remapping follows a slower time course. Ensemble activity was recorded simultaneously from CA3 and CA1 in rats exposed to two similar, novel environments. It was found that rate changes in response to novel sensory cue configurations can form immediately, just as during global remapping, in particular in CA3. The fast encoding of both spatial and nonspatial information in CA3 is consistent with a role for the autoassociative CA3 circuitry in the acquisition and expression of episodic memories. (c) 2006 Wiley-Liss, Inc.

关键词： remapping pattern separation population coding autoassociative networks episodic memory

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Precise Spatial coding is Preserved Along the Longitudinal Hippocampal Axis

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HIPPOCAMPUS 2014年第12期24卷 1533-1548页

作者： Keinath, Alexander T. Wang, Melissa E. Wann, Ellen G. Yuan, Robin K. Dudman, Joshua T. Muzzio, Isabel A. Univ Penn Dept Psychol Philadelphia PA 19104 USA Howard Hughes Med Inst Ashburn VA USA

Compared with the dorsal hippocampus, relatively few studies have characterized neuronal responses in the ventral hippocampus. In particular, it is unclear whether and how cells in the ventral region represent space and/or respond to contextual changes. We recorded from dorsal and ventral CA1 neurons in freely moving mice exposed to manipulations of visuospatial and olfactory contexts. We found that ventral cells respond to alterations of the visuospatial environment such as exposure to novel local cues, cue rotations, and contextual expansion in similar ways to dorsal cells, with the exception of cue rotations. Furthermore, we found that ventral cells responded to odors much more strongly than dorsal cells, particularly to odors of high valence. Similar to earlier studies recording from the ventral hippocampus in CA3, we also found increased scaling of place cell field size along the longitudinal hippocampal axis. Although the increase in place field size observed toward the ventral pole has previously been taken to suggest a decrease in spatial information coded by ventral place cells, we hypothesized that a change in spatial scaling could instead signal a shift in representational coding that preserves the resolution of spatial information. To explore this possibility, we examined population activity using principal component analysis (PCA) and neural location reconstruction techniques. Our results suggest that ventral populations encode a distributed representation of space, and that the resolution of spatial information at the population level is comparable to that of dorsal populations of similar size. Finally, through the use of neural network modeling, we suggest that the redundancy in spatial representation along the longitudinal hippocampal axis may allow the hippocampus to overcome the conflict between memory interference and generalization inherent in neural network memory. Our results indicate that ventral population activity is well suited for generali

关键词： ventral hippocampus interference generalization decoding reconstruction population coding

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A study of the science of taste: On the origins and influence of the core ideas

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BEHAVIORAL AND BRAIN SCIENCES 2008年第1期31卷 59-+页

作者： Erickson, Robert P. Duke Univ Dept Psychol Durham NC 27708 USA Duke Univ Dept Neurosci Durham NC 27708 USA Duke Univ Dept Neurobiol Durham NC 27708 USA

Our understanding of the sense of taste is largely based on research designed and interpreted in terms of the traditional four "basic" tastes: sweet, sour, salty, and bitter, and now a few more. This concept of basic tastes has no rational definition to test, and thus it has not been tested. As a demonstration, a preliminary attempt to test one common but arbitrary psychophysical definition of basic tastes is included in this article;that the basic tastes are unique in being able to account for other tastes. This definition was falsified in that other stimuli do about as well as the basic words and stimuli. To the extent that this finding might show analogies with other studies of receptor, neural, and psychophysical phenomena, the validity of the century-long literature of the science of taste based on a few "basics" is called into question. The possible origins, meaning, and influence of this concept are discussed. Tests of the model with control studies are suggested in all areas of taste related to basic tastes. As a stronger alternative to the basic tradition, the advantages of the across-fiber pattern model are discussed;it is based on a rational data-based hypothesis, and has survived attempts at falsification. Such "population coding" has found broad acceptance in many neural systems.

关键词： across-fiber pattern basic tastes distributed neural coding population coding psychophysics receptors reductionism systems biology taste

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Decorrelation of sensory-evoked neuronal responses in rat barrel cortex during postnatal development

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NEUROSCIENCE RESEARCH 2012年第4期73卷 312-320页

作者： Ikezoe, Koji Tamura, Hiroshi Kimura, Fumitaka Fujita, Ichiro Osaka Univ Cognit Neurosci Lab Grad Sch Frontier Biosci Toyonaka Osaka 5608531 Japan Osaka Univ Cognit Neurosci Lab Grad Sch Engn Sci Toyonaka Osaka 5608531 Japan Osaka Univ Ctr Informat & Neural Networks Toyonaka Osaka 5608531 Japan Osaka Univ Grad Sch Med Dept Mol Neurosci Suita Osaka 5650871 Japan

The ability to detect and discriminate sensory stimuli greatly improves with age. To better understand the neural basis of perceptual development, we studied the postnatal development of sensory responses in cortical neurons. Specifically, we analyzed neuronal responses to single-whisker deflections in the posteromedial barrel subfield (PMBSF) of the rat primary somatosensory cortex. Responses of PMBSF neurons showed a long onset latency and duration in the first postnatal week, but became fast and transient over the next few weeks. Trial-by-trial variations of single neuron responses did not change systematically with age, whereas the covariation of responses across trials between neurons (noise correlation) was high on postnatal day 5-6 (P5-6), and gradually decreased with age to near zero by P30-31. Computational analyses showed that pooled responses of multiple neurons became more reliable across stimulus trials with age. The period over which these changes occurred corresponds to the period when rats develop a full set of exploratory whisking behavior. We suggest that reduced noise correlation across a population of neurons, in addition to sharpening the temporal characteristics of single neuron responses, may help improve behavioral performance. (C) 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

关键词： Somatosensory cortex Whisker Multiple single-unit recording Pooling Noise correlation population coding Cross-correlogram Silicon probes

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Dual-Factor Representation of the Environmental Context in the Retrosplenial Cortex

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CEREBRAL CORTEX 2021年第5期31卷 2720-2728页

作者： Miller, Adam M. P. Serrichio, Anna C. Smith, David M. Cornell Univ Dept Psychol 236 Uris Hall Ithaca NY 14853 USA

The retrosplenial cortex (RSC) is thought to be involved in a variety of spatial and contextual memory processes. However, we do not know how contextual information might be encoded in the RSC or whether the RSC representations may be distinct from context representations seen in other brain regions such as the hippocampus. We recorded RSC neuronal responses while rats explored different environments and discovered 2 kinds of context representations: one involving a novel rate code in which neurons reliably fire at a higher rate in the preferred context regardless of spatial location, and a second involving context-dependent spatial firing patterns similar to those seen in the hippocampus. This suggests that the RSC employs a unique dual-factor representational mechanism to support contextual memory.

关键词： context memory population coding retrosplenial cortex spatial navigation

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Statistics of visual responses in primate inferotemporal cortex to object stimuli

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JOURNAL OF NEUROPHYSIOLOGY 2011年第3期106卷 1097-1117页

作者： Lehky, Sidney R. Kiani, Roozbeh Esteky, Hossein Tanaka, Keiji RIKEN Brain Sci Inst Cognit Brain Mapping Lab Wako Saitama 3510198 Japan Salk Inst Biol Studies Computat Neurosci Lab La Jolla CA USA Shahid Beheshti Univ Sch Med Res Grp Brain & Cognit Sci Tehran Iran Stanford Univ Sch Med Dept Neurobiol Palo Alto CA 94304 USA Stanford Univ Sch Med Howard Hughes Med Inst Palo Alto CA 94304 USA Sch Cognit Sci Inst Res Fundamental Sci Tehran Iran

Lehky SR, Kiani R, Esteky H, Tanaka K. Statistics of visual responses in primate inferotemporal cortex to object stimuli. J Neurophysiol 106: 1097-1117, 2011. First published May 11, 2011;doi:10.1152/jn.00990.2010.-We have characterized selectivity and sparseness in anterior inferotemporal cortex, using a large data set. Responses were collected from 674 monkey inferotemporal cells, each stimulated by 806 object photographs. This 806 x 674 matrix was examined in two ways: columnwise, looking at responses of a single neuron to all images (single-neuron selectivity), and rowwise, looking at the responses of all neurons caused by a single image (population sparseness). Selectivity and sparseness were measured as kurtosis of probability distributions. population sparseness exceeded single-neuron selectivity, with specific values dependent on the size of the data sample. This difference was principally caused by inclusion, within the population, of neurons with a variety of dynamic ranges (standard deviations of responses over all images). Statistics of large responses were examined by quantifying how quickly the upper tail of the probability distribution decreased (tail heaviness). This analysis demonstrated that population responses had heavier tails than single-neuron responses, consistent with the difference between sparseness and selectivity measurements. population responses with spontaneous activity subtracted had the heaviest tails, following a power law. The very light tails of single-neuron responses indicate that the critical feature for each neuron is simple enough to have a high probability of occurring within a limited stimulus set. Heavy tails of population responses indicate that there are a large number of different critical features to which different neurons are tuned. These results are inconsistent with some structural models of object recognition that posit that objects are decomposed into a small number of standard features.

关键词： monkey extrastriate object recognition population coding selectivity sparseness heavy tails power law Pareto distribution stable distribution

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