2012年7月27日金曜日

Perceptual Learning and Decision-Making in Human Medial Frontal Cortex

Thorsten Kahnt, Marcus Grueschow, Oliver Speck and John-Dylan Haynes
Neuron, Volume 70, Issue 3, 549-559, 12 May 2011

知覚学習のfMRI研究。学習過程は強化学習で説明できて、前帯状回(初期視覚野ではなく!)に学習された変数が保持されている。 http://www.cell.com/neuron/abstract/S0896-6273(11)00296-0 おもしろそう。後でちゃんと読もう。

The dominant view that perceptual learning is accompanied by changes in early sensory representations has recently been challenged. Here we tested the idea that perceptual learning can be accounted for by reinforcement learning involving changes in higher decision-making areas. We trained subjects on an orientation discrimination task involving feedback over 4 days, acquiring fMRI data on the first and last day. Behavioral improvements were well explained by a reinforcement learning model in which learning leads to enhanced readout of sensory information, thereby establishing noise-robust representations of decision variables. We find stimulus orientation encoded in early visual and higher cortical regions such as lateral parietal cortex and anterior cingulate cortex (ACC). However, only activity patterns in the ACC tracked changes in decision variables during learning. These results provide strong evidence for perceptual learning-related changes in higher order areas and suggest that perceptual and reward learning are based on a common neurobiological mechanism.

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