Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada.
eNeuro. 2021 Jan 15;8(1). doi: 10.1523/ENEURO.0383-20.2020. Print 2021 Jan-Feb.
The processing of visual motion is conducted by dedicated pathways in the primate brain. These pathways originate with populations of direction-selective neurons in the primary visual cortex, which projects to dorsal structures like the middle temporal (MT) and medial superior temporal (MST) areas. Anatomical and imaging studies have suggested that area V3A might also be specialized for motion processing, but there have been very few studies of single-neuron direction selectivity in this area. We have therefore performed electrophysiological recordings from V3A neurons in two macaque monkeys (one male and one female) and measured responses to a large battery of motion stimuli that includes translation motion, as well as more complex optic flow patterns. For comparison, we simultaneously recorded the responses of MT neurons to the same stimuli. Surprisingly, we find that overall levels of direction selectivity are similar in V3A and MT and moreover that the population of V3A neurons exhibits somewhat greater selectivity for optic flow patterns. These results suggest that V3A should be considered as part of the motion processing machinery of the visual cortex, in both human and non-human primates.
视觉运动的处理是由灵长类动物大脑中的特定通路进行的。这些通路起源于初级视觉皮层中具有方向选择性的神经元群体，它们投射到背侧结构，如中颞（MT）和内侧上颞（MST）区域。解剖学和影像学研究表明，V3A 区域也可能专门用于运动处理，但对该区域的单个神经元方向选择性的研究非常少。因此，我们在两只猕猴（一只雄性和一只雌性）中进行了 V3A 神经元的电生理记录，并测量了对包括平移运动在内的大量运动刺激的反应，以及更复杂的光流模式。为了进行比较，我们同时记录了 MT 神经元对相同刺激的反应。令人惊讶的是，我们发现 V3A 和 MT 中的整体方向选择性水平相似，而且 V3A 神经元群体对光流模式表现出更大的选择性。这些结果表明，V3A 应该被视为人类和非人类灵长类动物视觉皮层运动处理机制的一部分。
