Ikeda Takuro, Hikosaka Okihide
Department of Physiology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Neuron. 2003 Aug 14;39(4):693-700. doi: 10.1016/s0896-6273(03)00464-1.
Eye movements are often influenced by expectation of reward. Using a memory-guided saccade task with an asymmetric reward schedule, we show that visual responses of monkey SC neurons increase when the visual stimulus indicates an upcoming reward. The increase occurred in two distinct manners: (1) reactively, as an increase in the gain of the visual response when the stimulus indicated an upcoming reward; (2) proactively, as an increase in anticipatory activity when reward was expected in the neuron's response field. These effects were observed mostly in saccade-related SC neurons in the deeper layer which would receive inputs from the cortical eye fields and the basal ganglia. These results, together with recent findings, suggest that the gain modulation may be determined by the inputs from both the cortical eye fields and the basal ganglia, whereas the anticipatory bias may be derived mainly from the basal ganglia.
眼动常常受到对奖励的预期影响。使用具有不对称奖励机制的记忆引导扫视任务，我们发现当视觉刺激表明即将有奖励时，猴子上丘（SC）神经元的视觉反应会增强。这种增强以两种不同方式出现：（1）反应性增强，即当刺激表明即将有奖励时，视觉反应增益增加；（2）主动性增强，即当预期在神经元反应野中有奖励时，预期活动增加。这些效应主要在深层与扫视相关的上丘神经元中观察到，这些神经元会接收来自皮质眼区和基底神经节的输入。这些结果与最近的发现一起表明，增益调制可能由皮质眼区和基底神经节的输入共同决定，而预期偏差可能主要源自基底神经节。
