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INTRINSIC CIRCUITRY IN THE CAT SUPERIOR COLLICULUS - PROJECTIONS FROM THE SUPERFICIAL LAYERS

JOURNAL OF COMPARATIVE NEUROLOGY 1992年第2期315卷 230-243页

作者： BEHAN, M APPELL, PP UNIV WISCONSIN CTR NEUROSCIMADISONWI 53706

The neuroanatomical tracer Phaseolus vulgaris leucoagglutinin (PHA-L) was used to label the local projections of neurons whose cell bodies are located in the superficial layers of the cat superior colliculus. Small, localized groups of neurons in the superficial layers project to all regions of the ipsilateral colliculus, including the deep layers. Comparable distributions of labeled terminals are seen throughout the colliculus when the PHA-L injection site is located in the rostral, middle, or caudal one-third of the colliculus. In addition, there is some evidence of a topographic projection from superficial to deep layers. These results suggest that a complex anatomical substrate exists for communication between the superficial and deep layers of the colliculus. Connections such as these may underlie the transfer of visual information from neurons in the superficial layers to populations of neurons in the deep layers that respond prior to saccadic eye movements.

关键词： INTERNEURONS TECTUM ENSEMBLE population coding

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Olfactory learning modifies the expression of odour-induced oscillatory responses in the gamma (60-90 Hz) and beta (15-40 Hz) bands in the rat olfactory bulb

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EUROPEAN JOURNAL OF NEUROSCIENCE 2003年第2期17卷 350-358页

作者： Ravel, N Chabaud, P Martin, C Gaveau, V Hugues, E Tallon-Baudry, C Bertrand, O Gervais, R Univ Lyon 1 Inst Cognit Sci CNRS UMR 5015 F-69675 Bron France INSERM U280 F-69008 Lyon France

This study addressed the question of the possible functional relevance of two different oscillatory activities, beta and gamma (15-40 and 60-90 Hz, respectively) for perception and memory processes in olfactory areas of mammals. Local field potentials were recorded near relay olfactory bulb neurons while rats performed an olfactory discrimination task. Signals reflected the mass activity from this region and characteristics of oscillatory activities were used as an index of local synchrony. Beta and gamma oscillatory activities were quantified by time-frequency methods before during and after odour sampling. In rats early in their training, olfactory sampling was associated with a significant decrease in power in the gamma band in parallel with a weak but significant increase in the beta band (centred on 27 Hz). Several days later, in well-trained rats, the gamma oscillatory depression was significantly enhanced both in duration and amplitude. It appeared within the 500 ms time period preceding odour onset and was further reduced during the odour period. Concurrently the beta oscillatory response (now centred on 24 Hz) during odour sampling was amplified by a twofold factor. The beta band response was modulated according to the chemical nature of the stimuli and rat's behavioural response. This study showed for the first time that odour sampling in behaving animals is associated with a clear shift in the olfactory bulb neuronal activity from a gamma to a beta oscillatory regime. Moreover, the data stress the importance of studying the odour-induced beta activity and its relation to perception and memory.

关键词： olfactory system learning and memory discrimination population coding oscillatory activity neural plasticity

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A Sparse Probabilistic Code Underlies the Limits of Behavioral Discrimination

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CEREBRAL CORTEX 2020年第3期30卷 1040-1055页

作者： Sriram, Balaji Li, Lillian Cruz-Martin, Alberto Ghosh, Anirvan Univ Calif San Diego Div Biol La Jolla CA 92093 USA Biogen Res & Early Dev 225 Binney St Cambridge MA 02142 USA Boston Univ Dept Biol 5 Cummington Mall Boston MA 02215 USA Boston Univ Neurophoton Ctr Boston MA 02215 USA Boston Univ Dept Pharmacol & Expt Therapeut Boston MA 02215 USA

The cortical code that underlies perception must enable subjects to perceive the world at time scales relevant for behavior. We find that mice can integrate visual stimuli very quickly (<100 ms) to reach plateau performance in an orientation discrimination task. To define features of cortical activity that underlie performance at these time scales, we measured single-unit responses in the mouse visual cortex at time scales relevant to this task. In contrast to high-contrast stimuli of longer duration, which elicit reliable activity in individual neurons, stimuli at the threshold of perception elicit extremely sparse and unreliable responses in the primary visual cortex such that the activity of individual neurons does not reliably report orientation. Integrating information across neurons, however, quickly improves performance. Using a linear decoding model, we estimate that integrating information over 50-100 neurons is sufficient to account for behavioral performance. Thus, at the limits of visual perception, the visual system integrates information encoded in the probabilistic firing of unreliable single units to generate reliable behavior.

关键词： electrophysiology mouse behavior orientation discrimination population coding 2AFC

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Context- and Output Layer-Dependent Long-Term Ensemble Plasticity in a Sensory Circuit

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NEURON 2017年第5期93卷 1198-+页

作者： Yamada, Yoshiyuki Bhaukaurally, Khaleel Madarasz, Tamas J. Pouget, Alexandre Rodriguez, Ivan Carleton, Alan Univ Geneva Sch Med Dept Basic Neurosci 1 Rue Michel Servet CH-1211 Geneva 4 Switzerland Univ Geneva Geneva Neurosci Ctr CH-1211 Geneva Switzerland UCL Gatsby Computat Neurosci Unit London W1T 4JG England Univ Geneva Dept Genet & Evolut CH-1211 Geneva Switzerland

Sensory information is translated into ensemble representations by various populations of projection neurons in brain circuits. The dynamics of ensemble representations formed by distinct channels of output neurons in diverse behavioral contexts remains largely unknown. We studied the two output neuron layers in the olfactory bulb (OB), mitral and tufted cells, using chronic two-photon calcium imaging in awake mice. Both output populations displayed similar odor response profiles. During passive sensory experience, both populations showed reorganization of ensemble odor representations yet stable pattern separation across days. Intriguingly, during active odor discrimination learning, mitral but not tufted cells exhibited improved pattern separation, although both populations showed reorganization of ensemble representations. An olfactory circuitry model suggests that cortical feedback on OB interneurons can trigger both forms of plasticity. In conclusion, we show that different OB output layers display unique context-dependent long-term ensemble plasticity, allowing parallel transfer of non-redundant sensory information to downstream centers.

关键词： population coding cell assemblies associative learning experience-dependent plasticity pattern separation sensory representation olfaction olfactory bulb two-photon imaging genetically encoded calcium indicator

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Cracking the Neural Code for Sensory Perception by Combining Statistics, Intervention, and Behavior

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NEURON 2017年第3期93卷 491-507页

作者： Panzeri, Stefano Harvey, Christopher D. Piasini, Eugenio Latham, Peter E. Fellin, Tommaso Ist Italiano Tecnol Neural Computat Lab I-38068 Rovereto Italy Ist Italiano Tecnol Neural Coding Lab I-38068 Rovereto Italy Harvard Med Sch Dept Neurobiol Boston MA 02115 USA UCL Gatsby Computat Neurosci Unit London W1T 4JG England Ist Italiano Tecnol Opt Approaches Brain Funct Lab I-16163 Genoa Italy

The two basic processes underlying perceptual decisions-how neural responses encode stimuli, and how they inform behavioral choices-have mainly been studied separately. Thus, although many spatiotemporal features of neural population activity, or "neural codes," have been shown to carry sensory information, it is often unknown whether the brain uses these features for perception. To address this issue, we propose a new framework centered on redefining the neural code as the neural features that carry sensory information used by the animal to drive appropriate behavior;that is, the features that have an intersection between sensory and choice information. We show how this framework leads to a new statistical analysis of neural activity recorded during behavior that can identify such neural codes, and we discuss how to combine intersection-based analysis of neural recordings with intervention on neural activity to determine definitively whether specific neural activity features are involved in a task.

关键词： neural coding choice information optogenetics population coding behavior

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Color in the Cortex: single- and double-opponent cells

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VISION RESEARCH 2011年第7期51卷 701-717页

作者： Shapley, Robert Hawken, Michael J. NYU Ctr Neural Sci New York NY 10003 USA

This is a review of the research during the past 25 years on cortical processing of color signals. At the beginning of the period the modular view of cortical processing predominated. However, at present an alternative view, that color and form are linked inextricably in visual cortical processing, is more persuasive than it seemed in 1985. Also, the role of the primary visual cortex, V1, in color processing now seems much larger than it did in 1985. The re-evaluation of the important role of V1 in color vision was caused in part by investigations of human V1 responses to color, measured with functional magnetic resonance imaging, fMRI, and in part by the results of numerous studies of single-unit neurophysiology in non-human primates. The neurophysiological results have highlighted the importance of double-opponent cells in V1. Another new concept is population coding of hue, saturation, and brightness in cortical neuronal population activity. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Single-opponent Double-opponent population coding Context Modules

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Laminar dependence of neuronal correlations in visual cortex

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JOURNAL OF NEUROPHYSIOLOGY 2013年第4期109卷 940-947页

作者： Smith, Matthew A. Jia, Xiaoxuan Zandvakili, Amin Kohn, Adam Univ Pittsburgh Dept Ophthalmol Ctr Neural Basis Cognit Pittsburgh PA 15213 USA Univ Pittsburgh Dept Bioengn Ctr Neural Basis Cognit Pittsburgh PA 15213 USA Univ Pittsburgh Fox Ctr Vis Restorat Pittsburgh PA 15213 USA Albert Einstein Coll Med Dominick Purpura Dept Neurosci Bronx NY 10467 USA Albert Einstein Coll Med Dept Ophthalmol & Visual Sci Bronx NY 10467 USA

Smith MA, Jia X, Zandvakili A, Kohn A. Laminar dependence of neuronal correlations in visual cortex. J Neurophysiol 109: 940-947, 2013. First published November 28, 2012;doi:10.1152/jn.00846.2012.-Neuronal responses are correlated on a range of timescales. Correlations can affect population coding and may play an important role in cortical function. Correlations are known to depend on stimulus drive, behavioral context, and experience, but the mechanisms that determine their properties are poorly understood. Here we make use of the laminar organization of cortex, with its variations in sources of input, local circuit architecture, and neuronal properties, to test whether networks engaged in similar functions but with distinct properties generate different patterns of correlation. We find that slow timescale correlations are prominent in the superficial and deep layers of primary visual cortex (V1) of macaque monkeys, but near zero in the middle layers. Brief timescale correlation (synchrony), on the other hand, was slightly stronger in the middle layers of V1, although evident at most cortical depths. Laminar variations were also apparent in the power of the local field potential, with a complementary pattern for low frequency (<10 Hz) and gamma (30-50 Hz) power. Recordings in area V2 revealed a laminar dependence similar to V1 for synchrony, but slow timescale correlations were not different between the input layers and nearby locations. Our results reveal that cortical circuits in different laminae can generate remarkably different patterns of correlations, despite being tightly interconnected.

关键词： cortical layers neuronal correlation population coding V1 visual cortex

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Analysis and modelling of variability and covariability of population spike trains across multiple time scales

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NETWORK-COMPUTATION IN NEURAL SYSTEMS 2012年第1-2期23卷 76-103页

作者： Lyamzin, Dmitry R. Garcia-Lazaro, Jose A. Lesica, Nicholas A. UCL Ear Inst London WC1X 8EE England Univ Munich Div Neurobiol Dept Biol 2 Martinsried Germany

As multi-electrode and imaging technology begin to provide us with simultaneous recordings of large neuronal populations, new methods for modelling such data must also be developed. We present a model of responses to repeated trials of a sensory stimulus based on thresholded Gaussian processes that allows for analysis and modelling of variability and covariability of population spike trains across multiple time scales. The model framework can be used to specify the values of many different variability measures including spike timing precision across trials, coefficient of variation of the interspike interval distribution, and Fano factor of spike counts for individual neurons, as well as signal and noise correlations and correlations of spike counts across multiple neurons. Using both simulated data and data from different stages of the mammalian auditory pathway, we demonstrate the range of possible independent manipulations of different variability measures, and explore how this range depends on the sensory stimulus. The model provides a powerful framework for the study of experimental and surrogate data and for analyzing dependencies between different statistical properties of neuronal populations.

关键词： Dichotomized Gaussian noise correlations population coding Fano factor

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Learning-induced modulation of oscillatory activities in the mammalian olfactory system: The role of the centrifugal fibres

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JOURNAL OF PHYSIOLOGY-PARIS 2004年第4-6期98卷 467-478页

作者： Martin, C Gervais, R Chabaud, P Messaoudi, B Ravel, N Univ Lyon 1 CNRS UMR 5015 Inst Cognit Sci F-69675 Bron France

In the mammalian olfactory system, oscillations related to odour representation have been described in field potential activities. Previous results showed that in olfactory bulb (OB) of awake rats engaged in an olfactory learning, odour presentation produced a decrease of oscillations in gamma frequency range (60-90 Hz) associated with a power increase in beta frequency range (15-40 Hz). This response pattern was strongly amplified in trained animals. The aim of this work was twofold: whether learning also induces similar changes in OB target structures and whether Such OB response depends on its centrifugal inputs. Local field potentials (LFPs) were recorded through chronically implanted electrodes in the OB, piriform and enthorhinal cortices of freely moving rats performing in olfactory discrimination. Oscillatory activities characteristics (amplitude, frequency and time-course) were extracted in beta and gamma range by a wavelet analysis. First, we found that odour induced beta oscillatory activity was present not only in the OB, but also in the other olfactory structures. In each recording site, characteristics of the beta oscillatory responses were dependent of odour, structure and learning level. Unilateral section of the olfactory peduncle was made before training, and LFPs were symmetrically recorded in the two bulbs all along the acquisition of the learning task. Data showed that deprivation of centrifugal feedback led to an increase of spontaneous gamma activity. Moreover, under this condition olfactory learning was no longer associated with the typical large beta band. As a whole, learning modulation of the beta oscillatory response in olfactory structures may reflect activity of a distributed functional network involved in odour representation. (C) 2005 Elsevier Ltd. All rights reserved.

关键词： learning and memory olfactory system oscillations population coding

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Local field potentials indicate network state and account for neuronal response variability

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JOURNAL OF COMPUTATIONAL NEUROSCIENCE 2010年第3期29卷 567-579页

作者： Kelly, Ryan C. Smith, Matthew A. Kass, Robert E. Lee, Tai Sing Ctr Neural Basis Cognit Pittsburgh PA USA Carnegie Mellon Univ Dept Comp Sci Pittsburgh PA 15213 USA Univ Pittsburgh Dept Neurosci Pittsburgh PA USA Carnegie Mellon Univ Dept Stat Pittsburgh PA 15213 USA Carnegie Mellon Univ Machine Learning Dept Pittsburgh PA 15213 USA

Multineuronal recordings have revealed that neurons in primary visual cortex (V1) exhibit coordinated fluctuations of spiking activity in the absence and in the presence of visual stimulation. From the perspective of understanding a single cell's spiking activity relative to a behavior or stimulus, these network fluctuations are typically considered to be noise. We show that these events are highly correlated with another commonly recorded signal, the local field potential (LFP), and are also likely related to global network state phenomena which have been observed in a number of neural systems. Moreover, we show that attributing a component of cell firing to these network fluctuations via explicit modeling of the LFP improves the recovery of cell properties. This suggests that the impact of network fluctuations may be estimated using the LFP, and that a portion of this network activity is unrelated to the stimulus and instead reflects ongoing cortical activity. Thus, the LFP acts as an easily accessible bridge between the network state and the spiking activity.

关键词： Local field potential Correlation Network state Spontaneous activity Multielectrode array Decoding population coding

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