Studies using single-unit recording play a significant role in understanding the neural mechanisms of higher brain function such as perception and decision-making. The middle temporal visual area (MT) contains a rich concentration of motion direction- and binocular disparity-selective neurons, along with topographic maps for these features, making it a useful model system for studying the neural mechanisms underlying visual perception and visually guided behavior. Here we review recent cutting-edge research aimed at understanding the representation and processing of visual information by MT neurons, as well as the relationship between neural activity in MT and cognitive behavior.
Heterogeneity of functional units for neural computation has been well documented at all the level of hierarchy from individual neurons to entire brain. This heterogeneity has been gained in an adaptive manner, which is far different from the design principle of artificially developed computer. In this review, we first introduce empirical proofs of multi-scale heterogeneity in the neural representation based on our information theoretical analyses in the auditory cortex of rats. Second, our decoding-based analyses investigate how various kinds of neuronal activities are orchestrated in the representation. In light of these results, we discuss about the significance of common characteristics in the sensory cortex, such as the heterogeneity, sparse coding and columnar organization, in terms of an adaptive strategy of neural representation.
去る2009年10月30日から11月3日に，諏訪湖で開催された日本神経回路学会オータムスクールAscone2009（Autumn School for Computational Neuroscience）において，大澤五住先生（大阪大学大学院 生命機能研究科脳神経工学講座 視覚神経科学研究室）の講義が行われました．その講義内容とスライドを元に，筆者が講義録としてまとめたものです．大澤先生が話しているような形式にまとめていますが，筆者の理解で再構成したものです．本内容や表現に関する責任は筆者がおうものとします．