Representing where along with what information in a model of a cortical patch.
Representing where along with what information in a model of a cortical patch.
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DOI：
10.1371/journal.pcbi.1000012
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发表时间：
2008-03-21
影响因子：
4.3
通讯作者：
Treves A
中科院分区：
文献类型：
--
作者：
Roudi Y;Treves A
在现实世界中的行为需要灵活地组合和维护关于连续变量和离散变量的信息。在视觉领域，一些证据表明，一些皮层网络中的神经元可以同时表征物体的位置和身份信息，并在物体不再存在时保持这种组合表征。然而，这种组合表示的潜在网络机制尚不清楚。在本文中，我们通过对循环网络的理论分析来解决这个问题。我们提出了一个皮质网络模型，该模型可以从不完整的瞬态线索中检索有关物体身份的信息，同时表示它们的空间位置。我们的研究结果表明，有两个因素是使这成为可能的重要因素：A)循环连接的度量组织，B)神经元线性增益的空间局部变化。度量连通性使有关对象身份的信息本地化检索成为可能，而增益调制确保了在正确位置的本地化。重要的是，我们发现网络可以检索和保留的关于身份的信息量受到它保留的关于位置的信息量的强烈影响。这种平衡可以通过改变神经元增益的全局信号来控制。这些结果表明，解剖和生理特性，长期以来被认为是皮层网络的特征，自然赋予它们保持物体身份和位置的连接表征的能力。要形成一幅周围环境的连贯画面，就需要将物体的位置信息（在哪里的信息）和它们的身份信息（什么信息）结合起来。它还需要在刺激消失后短时间内保持这些组合信息的能力。在这里，我们提出了一个理论模型，说明这是如何在大脑中完成的，特别是当感觉输入不完整，并且缺少应该从存储在记忆中的信息中提供的信息时。主要观点是，皮质网络中的局部连通性可以形成局部活动状态。哪里的信息可以通过这些“突起”的位置来表示，哪些信息可以通过突起内神经元活动的精细结构来表示。我们表明，实现这个想法有一个困难：连接中的噪声和异质性会导致颠簸漂移，从而丢失信息。这个问题可以通过局部增加神经元增益来解决；然而，这干扰了检索信息并将其保存在工作记忆中。我们通过对模型的理论分析量化了这种干扰，并表明，尽管存在干扰，所提出的机制在检索信息和表示信息的位置方面是有效的。
Behaving in the real world requires flexibly combining and maintaining information about both continuous and discrete variables. In the visual domain, several lines of evidence show that neurons in some cortical networks can simultaneously represent information about the position and identity of objects, and maintain this combined representation when the object is no longer present. The underlying network mechanism for this combined representation is, however, unknown. In this paper, we approach this issue through a theoretical analysis of recurrent networks. We present a model of a cortical network that can retrieve information about the identity of objects from incomplete transient cues, while simultaneously representing their spatial position. Our results show that two factors are important in making this possible: A) a metric organisation of the recurrent connections, and B) a spatially localised change in the linear gain of neurons. Metric connectivity enables a localised retrieval of information about object identity, while gain modulation ensures localisation in the correct position. Importantly, we find that the amount of information that the network can retrieve and retain about identity is strongly affected by the amount of information it maintains about position. This balance can be controlled by global signals that change the neuronal gain. These results show that anatomical and physiological properties, which have long been known to characterise cortical networks, naturally endow them with the ability to maintain a conjunctive representation of the identity and location of objects. Forming a coherent picture of our surrounding environment requires combining visual information about the position of objects (where information) with information about their identity (what information). It also requires the ability to maintain this combined information for short periods of time after the stimulus is removed. Here, we propose a theoretical model of how this is accomplished in the brain, particularly when sensory input is incomplete, and missing what information should be supplied from what is stored in memory. The main idea is that local connectivity in cortical networks can allow the formation of localised states of activity. Where information can then be represented by the position of such “bumps”, and what information by the fine structure of the neuronal activity within them. We show that there is a difficulty with implementing this idea: noise and heterogeneity in connectivity cause bumps to drift, thereby losing where information. This problem can be solved by incorporating a localised increase in neuronal gain; this, however, interferes with retrieving what information and maintaining it in working memory. We quantify this interference via theoretical analysis of the model and show that, despite the interference, the proposed mechanism is an efficient one in retrieving what information while representing where information.
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影响因子：
2.5
作者：
DiCarlo, JJ;Maunsell, JHR
通讯作者：
Maunsell, JHR
影响因子：
2
作者：
Akdal, G;Hodgson, TL;Kennard, C
通讯作者：
Kennard, C
影响因子：
2.9
作者：
BUHMANN, J;DIVKO, R;SCHULTEN, K
通讯作者：
SCHULTEN, K
DOI：
10.1209/0295-5075/4/2/007
发表时间：
1987-07-15
期刊：
EUROPHYSICS LETTERS
影响因子：
--
作者：
DERRIDA, B;GARDNER, E;ZIPPELIUS, A
通讯作者：
ZIPPELIUS, A
影响因子：
25
作者：
Brefczynski, JA;DeYoe, EA
通讯作者：
DeYoe, EA