A continuous attractor network model without recurrent excitation: Maintenance and integration in the head direction cell system
A continuous attractor network model without recurrent excitation: Maintenance and integration in the head direction cell system
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DOI：
10.1007/s10827-005-6559-y
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发表时间：
2005-03-01
影响因子：
1.2
通讯作者：
Arleo, A
中科院分区：
文献类型：
--
作者：
Boucheny, C;Brunel, N;Arleo, A
基于头部方向系统的实验观察，我们研究了一个作为连续吸引子网络运行的三种群网络模型。该网络能够在没有选择性外部输入的情况下将角度变量（头部方向）存储在短期记忆中作为神经元活动的空间分布，并根据角速度输入准确地更新该变量。该网络由一个兴奋性种群和两个抑制性种群组成，种群之间相互连接，但同一种群的神经元内部没有连接。特别是，没有兴奋性到兴奋性的连接。角速度信号被表示为一个抑制群体（顺时针转动）或另一个抑制群体（逆时针转动）中的输入。该系统的研究使用的分析和数值方法相结合。由阈值线性神经元组成的简化模型的分析给出了以下条件的连通性：（i）空间选择性轮廓的出现，（ii）角速度输入的可靠积分，以及（iii）模型可以精确积分的角速度范围。数值模拟使我们能够研究所提出的方案在一个大型网络的尖峰神经元和比较他们的动态与头方向细胞记录在大鼠边缘系统。特别是，我们发现吸引子网络编码的方向表征可以通过外部线索快速更新，这与Zugaro等人（2003）在丘脑头部方向细胞中实验观察到的非常短的更新延迟一致。
Motivated by experimental observations of the head direction system, we study a three population network model that operates as a continuous attractor network. This network is able to store in a short-term memory an angular variable ( the head direction) as a spatial profile of activity across neurons in the absence of selective external inputs, and to accurately update this variable on the basis of angular velocity inputs. The network is composed of one excitatory population and two inhibitory populations, with inter-connections between populations but no connections within the neurons of a same population. In particular, there are no excitatory-to-excitatory connections. Angular velocity signals are represented as inputs in one inhibitory population ( clockwise turns) or the other ( counterclockwise turns). The system is studied using a combination of analytical and numerical methods. Analysis of a simplified model composed of threshold-linear neurons gives the conditions on the connectivity for (i) the emergence of the spatially selective profile, (ii) reliable integration of angular velocity inputs, and (iii) the range of angular velocities that can be accurately integrated by the model. Numerical simulations allow us to study the proposed scenario in a large network of spiking neurons and compare their dynamics with that of head direction cells recorded in the rat limbic system. In particular, we show that the directional representation encoded by the attractor network can be rapidly updated by external cues, consistent with the very short update latencies observed experimentally by Zugaro et al. ( 2003) in thalamic head direction cells.