NEURAL COMPUTATIONS IN VISUAL CORTEX

该研究包括两个互补的方法，以进一步了解视觉信息是如何在视觉皮层，特别是初级视觉皮层的表示和处理。 目的我将集中在神经放电的时间结构。 这些目标将决定（a）神经放电的时间模式在多大程度上有助于表征特定种类的视觉信息，包括基本的空间特征和颜色;（B）视觉信息的时间表征是否能促进随后的视觉加工;以及（c）时间编码的关系（单个神经元的尖峰序列内的视觉信息的表示）到空间编码（视觉信息在两个或多个神经元之间的表达）。 将使用标准视觉刺激（条形、光栅和复合光栅）。 直方图，傅立叶和互相关分析的通常的分析方法，将增加一个家庭的新方法，最近在这个实验室开发的，基于嵌入到度量空间的神经反应。目标二将侧重于通过感受野的次区域产生反应动力学。 主要的策略将是一个适应的m序列技术，以允许分析的时间结构的反应。 通过比较由所有尖峰、由突发和由“可靠”尖峰产生的感受野图，我们将确定这些时间结构在多大程度上参与特征的信号传递和提取。 m序列分析将显示这些时间结构在多大程度上是由响应特性的整体调制、特定的感受野子区域或空间扩展区域上的特定相互作用引起的。这些定量实验的目标是对视觉皮层如何在现象学（目的I）和机械学（目的II）水平上表示和处理信息的新的定性见解。 这将成为更好地了解健康和疾病中大脑功能的基础。

The proposed research consists of two complementary approaches to further the understanding of how visual information is represented and processed in visual cortex, particularly primary visual cortex. Aims I will focus on the temporal structure of the neural discharge. These aims will determine (a) the extent to which the temporal pattern of a neural discharge contributes to the representation of particular kinds of visual information, including elementary spatial features and color; (b) whether the temporal representation of visual information can facilitate subsequent visual processing; and (c) the relationship of temporal coding (representation of visual information within the spike train of a single neuron) to spatial coding (representation of visual information across two or more neurons). Standard visual stimuli (bars, gratings, and compound gratings) will be used. The usual analytical approaches of histogram, Fourier, and cross-correlation analysis will be augmented by a family of new methods recently developed in this laboratory, based on the embedding of neural responses into a metric space. Aim II will focus on the generation of response dynamics by subregions of the receptive field. The main strategy will be an adaptation of the m-sequence technique to allow analysis of the temporal structure of the response. Through comparison of receptive field maps generated by all spikes, by bursts, and by "reliable" spikes, we will determine to what extent these temporal structures participate in the signaling and extraction of features. The m-sequence analysis will show the extent to which these temporal structures arise from an overall modulation of response properties, specific receptive field subregions, or specific interactions over an extended region of space. The goals of these quantitative experiments are new qualitative insights into how the visual cortex represents and processes information, on phenomenological (Aims I) and mechanistic (Aim II) levels. This will serve as a basis for a better understanding of brain function in health and disease.