Behavioral constraints in the development of neuronal properties:: A cortical model embedded in a real-world device
Behavioral constraints in the development of neuronal properties:: A cortical model embedded in a real-world device
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DOI：
10.1093/cercor/8.4.346
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发表时间：
1998-06-01
期刊：
影响因子：
3.7
通讯作者：
Sporns, O
中科院分区：
文献类型：
--
作者：
Almássy, N;Edelman, GM;Sporns, O
生物体对不同的、往往是新的刺激进行分类的能力取决于它们与环境的持续相互作用。在视觉等通道中，分类需要皮层神经元对复杂视觉刺激产生选择性和不变反应。行为如何影响这些神经元的反应？由于许多神经和行为变量之间复杂的多层次相互作用，这一问题的分析变得困难。为了缓解这一困难，我们通过合成神经建模的方法研究了模式选择性神经元反应的发展和持续可塑性。为此，我们构建了达尔文V，它由一个模拟的神经元模型组成，嵌入在一个能够运动和自主行为的真实设备中。神经元模型由四个主要组成部分组成：视觉系统(包括皮质和皮质下网络)；基于电导的味觉系统；能够触发行为的运动神经元集合；以及扩散上升(价值)系统。建立模型的视觉皮层由两个区域组成：一个对基本特征作出反应的地形图，连接到一个由最初非选择性神经元单元组成的高阶地图。随着时间的推移，达尔文五号在其环境中的行为过程中，会遇到许多由黑色金属立方体组成的物体，这些立方体显示出不同模式的白色斑点和条纹。最初，缺乏特定的高阶视觉反应不允许视觉模式辨别，食欲和厌恶行为仅由“味道”(物体的表面传导性)触发。然而，在感觉体验的过程中，视觉和感觉运动连接强度发生了变化，产生了两个主要后果。首先，较高视觉区域内的单位获得既具有模式选择性又具有平移不变性的反应。其次，作为价值体系运行的结果，这些反应与适当的行为联系在一起。对这些变化后的达尔文五世的分析表明，自生成运动的连续性对于模式选择性和翻译不变反应的发展是必不可少的。伴随而来的对中央凹而不是旁中央凹物体的偏好的发展被发现是由于与被达尔文V的中央安装的效应器(口鼻)抓住的物体立方体的行为交互增加所致。最后，即使在发展出更高阶的视觉反应之后，对更频繁遇到的物体的视觉反应继续增强，而其他反应被减弱。总体而言，对达尔文五世在多个组织水平上的详细研究提供了一个启发式的例子，揭示了行为和环境相互作用在特殊神经元复杂反应的发展中所起的关键作用。
The ability of organisms to categorize diverse and often novel stimuli depends on ongoing interactions with their environment. In a modality such as vision, categorization requires the generation of both selective and invariant responses of cortical neurons to complex visual stimuli. How does behavior contribute to shaping the responses of these neurons? Analysis of this question is made difficult by the complex multilevel interactions between many neural and behavioral variables. To mitigate this difficulty, we studied the development and ongoing plasticity of pattern-selective neuronal responses by means of synthetic neural modeling. For this purpose, we constructed Darwin V, which consists of a simulated neuronal model embedded in a real-world device that is capable of motion and autonomous behavior. The neuronal model consists of four major components: a visual system (containing cortical and subcortical networks); a taste system based on conductance; sets of motor neurons capable of triggering behavior; and a diffuse ascending (value) system. The modeled visual cortex consists of two areas: a topographic map responsive to elementary features connected to a higher-order map composed of initially non-selective neuronal units. During behavior over time in its environment, Darwin V encounters numerous objects consisting of black metal cubes displaying different patterns of white blobs and stripes. Initially, the lack of specific higher-order visual responses does not allow visual pattern discrimination, and appetitive and aversive behaviors are triggered by the 'taste' (surface conductivity of objects) alone. In the course of sensory experience, however, changes occur in visual and sensorimotor connection strengths, with two major consequences. First, units within the higher visual area acquire responses that are both pattern selective and translation invariant. Second, as a result of the operation of the value system, these responses become linked to appropriate behaviors. Analysis of Darwin V after such changes indicates that the continuity of self-generated movements is essential for the development of pattern-selective and translation-invariant responses. The concomitant development of a preference for foveal over parafoveal objects was found to be due to increased behavioral interactions with object cubes gripped by the centrally mounted effector (snout) of Darwin V. Finally, even after development of higher-order visual responses, visual responses to more frequently encountered objects continued to be enhanced, while other responses were diminished. Overall, the detailed study of Darwin V over multiple levels of organization provides a heuristically revealing example of the crucial role played by behavioral and environmental interactions in the development of complex responses by specialized neurons.