Neural basis of pattern masking and texture segregation

描述(申请人提供)：神经元是基本的加工过程 大脑中的单位；然而，尚不清楚神经活动是如何导致 感知和行为等复杂的过程。通过探索神经 作为人类模式视觉基础的信号，拟议的实验将测试 认为这些过程是由许多人的共同活动调节的假说 神经元。在所有三个实验中使用的一般方法是将 对由其引起的神经活动的刺激的心理物理知觉 功能磁共振成像测量早期视觉区域的刺激。在第一个实验中， 探讨了模式掩蔽的神经基础。受试者进行对比 辨别任务，同时用fMRI测量神经活动。这个 该提案中报告的初步数据显示，在刺激条件下 产生掩蔽，对目标的神经反应被抑制。 将对这些数据和来自其他受试者的数据进行进一步的分析 通过同时将心理物理和功能磁共振数据与响应进行匹配 具有多个决策规则的归一化函数，以尝试识别哪些 在模式检测任务中汇集信息。第二个目标扩展到 第一名的结果。模式可以被发生的刺激所掩盖 异步(前向掩码)。在第三个实验中，实验被扩展到 观察V1之外的情况，并显示神经信号编码用于感知体验和 而不是纹理辨别任务中刺激的物理特征。

DESCRIPTION (provided by applicant): Neurons are the fundamental processing unit in the brain; however, it is not known how neural activity leads to complex processes such as perception and behavior. By exploring the neural signals which underlie human pattern vision, the proposed experiments will test the hypothesis that these processes are mediated by the pooled activity of many neurons. The general approach used in all three experiments is to link psychophysical perception of a stimulus to the neural activity evoked by that stimulus in early visual areas as measured by fMRI. In the first experiment, the neural basis of pattern masking is explored. Subjects perform a contrast discrimination task while the neural activity is measured by fMRI. The preliminary data reported in this proposal show that under stimulus conditions which produce masking, the neural responses to the target are suppressed. Further analysis will be done on this data and on data from additional subjects by simultaneously fitting the psychophysical and fMRI data with a response normalization function with several decision rules to try to identify which information is pooled in a pattern detection task. The second aim expands on the results of the firsts. Patterns can be masked by stimuli which occur asynchronously (forward masking). In the third the experiments are extended to look outside V1 and show that neural signals code for perceptual experience and not physical features of a stimulus in a texture discrimination task.