Solomon Selina S, Chen Spencer C, Morley John W, Solomon Samuel G
ARC Centre of Excellence in Vision Science, Sydney, NSW, Australia Discipline of Physiology, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, NSW 2006, Australia.
School of Medicine, University of Western Sydney, Campbelltown, NSW 2560, Australia.
Cereb Cortex. 2015 Sep;25(9):3182-96. doi: 10.1093/cercor/bhu111. Epub 2014 Jun 5.
In humans and other primates, the analysis of visual motion includes populations of neurons in the middle-temporal (MT) area of visual cortex. Motion analysis will be constrained by the structure of neural correlations in these populations. Here, we use multi-electrode arrays to measure correlations in anesthetized marmoset, a New World monkey where area MT lies exposed on the cortical surface. We measured correlations in the spike count between pairs of neurons and within populations of neurons, for moving dot fields and moving gratings. Correlations were weaker in area MT than in area V1. The magnitude of correlations in area MT diminished with distance between receptive fields, and difference in preferred direction. Correlations during presentation of moving gratings were stronger than those during presentation of moving dot fields, extended further across cortex, and were less dependent on the functional properties of neurons. Analysis of the timescales of correlation suggests presence of 2 mechanisms. A local mechanism, associated with near-synchronous spiking activity, is strongest in nearby neurons with similar direction preference and is independent of visual stimulus. A global mechanism, operating over larger spatial scales and longer timescales, is independent of direction preference and is modulated by the type of visual stimulus presented.
在人类和其他灵长类动物中，视觉运动分析涉及视觉皮层中颞中区（MT区）的神经元群体。运动分析将受到这些群体中神经相关性结构的限制。在这里，我们使用多电极阵列来测量麻醉的狨猴（一种新大陆猴，其MT区位于皮质表面）中的相关性。我们测量了移动点场和移动光栅情况下神经元对之间以及神经元群体内部的尖峰计数相关性。MT区的相关性比V1区弱。MT区相关性的大小随着感受野之间的距离以及偏好方向的差异而减小。移动光栅呈现期间的相关性比移动点场呈现期间的相关性更强，在整个皮层中延伸得更远，并且对神经元功能特性的依赖性更小。相关性时间尺度分析表明存在两种机制。一种局部机制，与近同步尖峰活动相关，在具有相似方向偏好的附近神经元中最强，并且与视觉刺激无关。一种全局机制，在更大的空间尺度和更长的时间尺度上起作用，与方向偏好无关，并受所呈现视觉刺激类型的调节。
