检索结果-内蒙古大学图书馆

Speed-invariant encoding of looming object distance requires power law spike rate adaptation

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2013年第33期110卷 13624-13629页

作者： Clarke, Stephen E. Naud, Richard Longtin, Andre Maler, Leonard Univ Ottawa Dept Cellular & Mol Med Ottawa ON K1H 8M5 Canada Univ Ottawa Dept Phys Ottawa ON K1H 8M5 Canada

neural representations of a moving object's distance and approach speed are essential for determining appropriate orienting responses, such as those observed in the localization behaviors of the weakly electric fish, Apteronotus leptorhynchus. We demonstrate that a power law form of spike rate adaptation transforms an electroreceptor afferent's response to "looming" object motion, effectively parsing information about distance and approach speed into distinct measures of the firing rate. Neurons with dynamics characterized by fixed time scales are shown to confound estimates of object distance and speed. Conversely, power law adaptation modifies an electroreceptor afferent's response according to the time scales present in the stimulus, generating a rate code for looming object distance that is invariant to speed and acceleration. Consequently, estimates of both object distance and approach speed can be uniquely determined from an electroreceptor afferent's firing rate, a multiplexed neural code operating over the extended time scales associated with behaviorally relevant stimuli.

关键词： spike frequency adaptation perceptual invariance sensory transformations neural coding

来源：评论

学校读者我要写书评

暂无评论

neural coding of temporal information in auditory thalamus and cortex

引用

NEUROSCIENCE 2008年第1期154卷 294-303页

作者： Wang, X. Lu, T. Bendor, D. Bartlett, E. Johns Hopkins Univ Sch Med Dept Biomed Engn Lab Auditory Neurophysiol Baltimore MD 21205 USA

How the brain processes temporal information embedded in sounds is a core question in auditory research. This article synthesizes recent studies from our laboratory regarding neural representations of time-varying signals in auditory cortex and thalamus in awake marmoset monkeys. Findings from these studies show that 1) the primary auditory cortex (A1) uses a temporal representation to encode slowly varying acoustic signals and a firing rate-based representation to encode rapidly changing acoustic signals, 2) the dual temporal-rate representations in A1 represent a progressive transformation from the auditory thalamus, 3) firing rate-based representations in the form of monotonic rate-code are also found to encode slow temporal repetitions in the range of acoustic flutter in A1 and more prevalently in the cortical fields rostral to A1 in the core region of marmoset auditory cortex, suggesting further temporal-to-rate transformations in higher cortical areas. These findings indicate that the auditory cortex forms internal representations of temporal characteristics of sounds that are no longer faithful replicas of their acoustic structures. We suggest that such transformations are necessary for the auditory cortex to perform a wide range of functions including sound segmentation, object processing and multi-sensory integration. (c) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.

关键词： auditory cortex medial geniculate body marmoset temporal processing neural coding

来源：评论

学校读者我要写书评

暂无评论

neural coding OF TEMPORAL INFORMATION IN AUDITORY THALAMUS AND CORTEX (vol 154, pg 294, 2008)

引用

NEUROSCIENCE 2008年第2期157卷 483-493页

作者： Wang, X. Lu, T. Bendor, D. Bartlett, E. Johns Hopkins Univ Sch Med Dept Biomed Engn Lab Auditory Neurophysiol Baltimore MD 21205 USA

How the brain processes temporal information embedded in sounds is a core question in auditory research. This article synthesizes recent studies from our laboratory regarding neural representations of time-varying signals in auditory cortex and thalamus in awake marmoset monkeys. Findings from these studies show that 1) the primary auditory cortex (A1) uses a temporal representation to encode slowly varying acoustic signals and a firing rate–based representation to encode rapidly changing acoustic signals, 2) the dual temporal-rate representations in A1 represent a progressive transformation from the auditory thalamus, 3) firing rate–based representations in the form of a monotonic rate-code are also found to encode slow temporal repetitions in the range of acoustic flutter in A1 and more prevalently in the cortical fields rostral to A1 in the core region of marmoset auditory cortex, suggesting further temporal-to-rate transformations in higher cortical areas. These findings indicate that the auditory cortex forms internal representations of temporal characteristics of sounds that are no longer faithful replicas of their acoustic structures. We suggest that such transformations are necessary for the auditory cortex to perform a wide range of functions including sound segmentation, object processing and multi-sensory integration.

关键词： auditory cortex medial geniculate body marmoset temporal processing neural coding

来源：评论

学校读者我要写书评

暂无评论

Retinal prosthetic strategy with the capacity to restore normal vision

引用

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2012年第37期109卷 15012-15017页

作者： Nirenberg, Sheila Pandarinath, Chethan Cornell Univ Weill Med Coll Dept Physiol & Biophys New York NY 10065 USA

Retinal prosthetics offer hope for patients with retinal degenerative diseases. There are 20-25 million people worldwide who are blind or facing blindness due to these diseases, and they have few treatment options. Drug therapies are able to help a small fraction of the population, but for the vast majority, their best hope is through prosthetic devices [reviewed in Chader et al. (2009) Prog Brain Res 175:317-332]. Current prosthetics, however, are still very limited in the vision that they provide: for example, they allow for perception of spots of light and high-contrast edges, but not natural images. Efforts to improve prosthetic capabilities have focused largely on increasing the resolution of the device's stimulators (either electrodes or optogenetic transducers). Here, we show that a second factor is also critical: driving the stimulators with the retina's neural code. Using the mouse as a model system, we generated a prosthetic system that incorporates the code. This dramatically increased the system's capabilities-well beyond what can be achieved just by increasing resolution. Furthermore, the results show, using 9,800 optogenetically stimulated ganglion cell responses, that the combined effect of using the code and high-resolution stimulation is able to bring prosthetic capabilities into the realm of normal image representation.

关键词： neural prosthetic retinal degeneration vision restoration neural coding macular degeneration

来源：评论

学校读者我要写书评

暂无评论

A novel test to determine the significance of neural selectivity to single and multiple potentially correlated stimulus features

引用

JOURNAL OF NEUROSCIENCE METHODS 2012年第1期210卷 49-65页

作者： Ince, Robin A. A. Mazzoni, Alberto Bartels, Andreas Logothetis, Nikos K. Panzeri, Stefano Ist Italiano Tecnol Robot Brain & Cognit Sci Dept I-16163 Genoa Italy Max Planck Inst Biol Cybernet D-72076 Tubingen Germany Bernstein Ctr Computat Neurosci Tubingen Germany Univ Tubingen Ctr Integrat Neurosci Vis & Cognit Lab D-72076 Tubingen Germany Univ Manchester Div Imaging Sci & Biomed Engn Manchester M13 9PT Lancs England Univ Glasgow Inst Neurosci & Psychol Glasgow Lanark Scotland

Mutual information is a principled non-linear measure of dependence between stochastic variables, which is widely used to study the selectivity of neural responses to external stimuli. Here we define and develop a set of novel statistical independence tests based on mutual information, which quantify the significance of neural selectivity to either single features or to multiple, potentially correlated stimulus features like those often present in naturalistic stimuli. If the values of different features are correlated during stimulus presentation, it is difficult to establish if one feature is genuinely encoded by the response, or if it instead appears to be encoded only as a side effect of its correlation with another genuinely represented feature. Our tests provide a way to disambiguate between these two possibilities. We use realistic simulations of neural responses tuned to one or more correlated stimulus features to investigate how limited sampling bias correction procedures affect the statistical power of such independence tests, and we characterize the regimes in which the distribution of information values under the null hypothesis can be approximated by simple distributions (Chi-square or Gaussian). Finally, we apply these tests to experimental data to determine the significance of tuning of the band limited power (BLP) of the gamma [30-100 Hz] frequency range of the primary visual cortical local field potential to multiple correlated features during presentation of naturalistic movies. We show that gamma BLP carries significant, genuine information about orientation, space contrast and time contrast, despite the strong correlations between these features. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Vision LFP neural coding Natural movies Mutual information Oscillations Gamma band

来源：评论

学校读者我要写书评

暂无评论

Conditional modeling and the jitter method of spike resampling

引用

JOURNAL OF NEUROPHYSIOLOGY 2012年第2期107卷 517-531页

作者： Amarasingham, Asohan Harrison, Matthew T. Hatsopoulos, Nicholas G. Geman, Stuart Brown Univ Div Appl Math Providence RI 02912 USA CUNY Dept Math New York NY 10021 USA CUNY Grad Ctr Program Cognit Neurosci New York NY 10021 USA Univ Chicago Dept Organismal Biol & Anat Comm Computat Neurosci & Neurobiol Chicago IL 60637 USA

Amarasingham A, Harrison MT, Hatsopoulos NG, Geman S. Conditional modeling and the jitter method of spike resampling. J Neurophysiol 107: 517-531, 2012. First published October 26, 2011;doi:10.1152/jn.00633.2011.-The existence and role of fine-temporal structure in the spiking activity of central neurons is the subject of an enduring debate among physiologists. To a large extent, the problem is a statistical one: what inferences can be drawn from neurons monitored in the absence of full control over their presynaptic environments? In principle, properly crafted resampling methods can still produce statistically correct hypothesis tests. We focus on the approach to resampling known as jitter. We review a wide range of jitter techniques, illustrated by both simulation experiments and selected analyses of spike data from motor cortical neurons. We rely on an intuitive and rigorous statistical framework known as conditional modeling to reveal otherwise hidden assumptions and to support precise conclusions. Among other applications, we review statistical tests for exploring any proposed limit on the rate of change of spiking probabilities, exact tests for the significance of repeated fine-temporal patterns of spikes, and the construction of acceptance bands for testing any purported relationship between sensory or motor variables and synchrony or other fine-temporal events.

关键词： spike timing neural coding jitter hypothesis testing conditional inference synchrony

来源：评论

学校读者我要写书评

暂无评论

Incorporation of new information into prefrontal cortical activity after learning working memory tasks

引用

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 2012年第12期109卷 4651-4656页

作者： Meyers, Ethan M. Qi, Xue-Lian Constantinidis, Christos MIT Dept Brain & Cognit Sci McGovern Inst Cambridge MA 02139 USA Wake Forest Univ Bowman Gray Sch Med Dept Neurobiol & Anat Winston Salem NC 27157 USA

The ability to learn new tasks requires that new information is integrated into neural systems that already support other behaviors. To study how new information is incorporated into neural representations, we analyzed single-unit recordings from the prefrontal cortex (PFC), a brain region important for task acquisition and working memory, before and after monkeys learned to perform two behavioral tasks. A population-decoding analysis revealed a large increase in task-relevant information, and smaller changes in stimulus-related information, after training. This new information was contained in dynamic patterns of neural activity, with many individual neurons containing the new task-relevant information for only relatively short periods of time in the midst of other large firing rate modulations. Additionally, we found that stimulus information could be decoded with high accuracy only from dorsal PFC, whereas task-relevant information was distributed throughout both dorsal and ventral PFC. These findings help resolve a controversy about whether PFC is innately specialized to process particular types of information or whether its responses are completely determined by task demands by showing there is both regional specialization within PFC that was present before training, as well as more widespread task-relevant information that is a direct result of learning. The results also show that information is incorporated into PFC through the emergence of a small population of highly selective neurons that overlay new signals on top of patterns of activity that contain information about previously encoded variables, which gives insight into how information is coded in neural activity.

关键词： neural coding task learning Macaque vision principal sulcus

来源：评论

学校读者我要写书评

暂无评论

Model architecture for associative memory in a neural network of spiking neurons

引用

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2012年第3期391卷 843-848页

作者： Agnes, Everton J. Erichsen, Rubem, Jr. Brunnet, Leonardo G. Univ Fed Rio Grande do Sul Inst Fis BR-91501970 Porto Alegre RS Brazil

A synaptic connectivity model is assembled on a spiking neuron network aiming to build up a dynamic pattern recognition system. The connection architecture includes gap junctions and both inhibitory and excitatory chemical synapses based on Hebb's hypothesis. The network evolution resulting from external stimulus is sampled in a properly defined frequency space. Neurons' responses to different current injections are mapped onto a subspace using Principal Component Analysis. Departing from the base attractor, related to a quiescent state, different external stimuli drive the network to different fixed points through specific trajectories in this subspace. (C) 2011 Elsevier B.V. All rights reserved.

关键词： neural networks Chemical synapses Gap junctions Map-based neuron neural coding Principal Component Analysis

来源：评论

学校读者我要写书评

暂无评论

Preparing for the unpredictable: adaptive feedback enhances the response to unexpected communication signals

引用

JOURNAL OF NEUROPHYSIOLOGY 2012年第4期107卷 1241-1246页

作者： Marsat, Gary Maler, Leonard Univ Ottawa Dept Cellular & Mol Med Ottawa ON Canada Univ Ottawa Ctr Neural Dynam Ottawa ON Canada

Marsat G, Maler L. Preparing for the unpredictable: adaptive feedback enhances the response to unexpected communication signals. J Neurophysiol 107: 1241-1246, 2012. First published December 7, 2011;doi:10.1152/jn.00982.2011.-To interact with the environment efficiently, the nervous system must generate expectations about redundant sensory signals and detect unexpected ones. neural circuits can, for example, compare a prediction of the sensory signal that was generated by the nervous system with the incoming sensory input, to generate a response selective to novel stimuli. In the first-order electrosensory neurons of a gymnotiform electric fish, a negative image of low-frequency redundant communication signals is subtracted from the neural response via feedback, allowing unpredictable signals to be extracted. Here we show that the cancelling feedback not only suppresses the predictable signal but also actively enhances the response to the unpredictable communication signal. A transient mismatch between the predictive feedback and incoming sensory input causes both to be positive: the soma is suddenly depolarized by the unpredictable input, whereas the neuron's apical dendrites remain depolarized by the lagging cancelling feedback. The apical dendrites allow the backpropagation of somatic spikes. We show that backpropagation is enhanced when the dendrites are depolarized, causing the unpredictable excitatory input to evoke spike bursts. As a consequence, the feedback driven by a predictable low-frequency signal not only suppresses the response to a redundant stimulus but also induces a bursting response triggered by unpredictable communication signals.

关键词： neural coding sensory processing backpropagation bursting electric fish parallel fibers predictive feedback pyramidal cells

来源：评论

学校读者我要写书评

暂无评论

Decoding 3D reach and grasp from hybrid signals in motor and premotor cortices: spikes, multiunit activity, and local field potentials

引用

JOURNAL OF NEUROPHYSIOLOGY 2012年第5期107卷 1337-1355页

作者： Bansal, Arjun K. Truccolo, Wilson Vargas-Irwin, Carlos E. Donoghue, John P. Brown Univ Dept Neurosci Providence RI 02912 USA Brown Univ Brown Inst Brain Sci Providence RI 02912 USA Massachusetts Gen Hosp Dept Neurol Boston MA 02114 USA Dept Vet Affairs Med Ctr Rehabil Res & Dev Serv Providence RI USA

Bansal AK, Truccolo W, Vargas-Irwin CE, Donoghue JP. Decoding 3D reach and grasp from hybrid signals in motor and premotor cortices: spikes, multiunit activity, and local field potentials. J Neurophysiol 107: 1337-1355, 2012. First published December 7, 2011;doi: 10.1152/jn.00781.2011.-neural activity in motor cortex during reach and grasp movements shows modulations in a broad range of signals from single-neuron spiking activity (SA) to various frequency bands in broadband local field potentials (LFPs). In particular, spatiotemporal patterns in multiband LFPs are thought to reflect dendritic integration of local and interareal synaptic inputs, attentional and preparatory processes, and multiunit activity (MUA) related to movement representation in the local motor area. Nevertheless, the relationship between multiband LFPs and SA, and their relationship to movement parameters and their relative value as brain-computer interface (BCI) control signals, remain poorly understood. Also, although this broad range of signals may provide complementary information channels in primary (MI) and ventral premotor (PMv) areas, areal differences in information have not been systematically examined. Here, for the first time, the amount of information in SA and multiband LFPs was compared for MI and PMv by recording from dual 96-multielectrode arrays while monkeys made naturalistic reach and grasp actions. Information was assessed as decoding accuracy for 3D arm end point and grip aperture kinematics based on SA or LFPs in MI and PMv, or combinations of signal types across areas. In contrast with previous studies with <= 16 simultaneous electrodes, here ensembles of > 16 units (on average) carried more information than multiband, multichannel LFPs. Furthermore, reach and grasp information added by various LFP frequency bands was not independent from that in SA ensembles but rather typically less than and primarily contained within the latter. Notably, MI and PMv did not show a parti

关键词： motor cortex neural signals neural coding brain-machine interfaces neural prosthesis

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：