Probing the cognitive brain functions with the oculomotor system

在这项研究中，我们研究了控制眼跳的神经回路的基本结构，以及回路的活动如何以依赖于上下文的方式进行调制。(1)At在局部回路水平上，阐明了上级丘（SC）深层神经元爆发产生的神经机制。我们发现这种爆发是通过NMDA受体介导的传递和局部循环网络产生的。GABA能抑制的释放对于回路表现出爆发是必不可少的。(2)We在视觉引导扫视任务中，记录大脑脚桥被盖核（PPTN）神经元的活动，PPTN是SC胆碱能输入的来源。我们发现猴在注视注视点和扫视时，一组PPTN神经元出现紧张性放电。当预期奖励量较大时，神经元表现出较高的活性，而当预期奖励量较小时，活性较低。这些结果表明， ...更多信息 PPTN神经元编码预测奖励。考虑到PPTN神经元投射到黑质中的多巴胺神经元，多巴胺神经元已被证明编码奖励预测误差，PPTN神经元的活动被认为用于计算多巴胺神经元处的奖励预测误差。(3)We研究了单侧初级视皮层（V1）损伤猴的扫视运动。这些V1损害的猴子可以对盲场中呈现的目标进行视觉引导的扫视。这些猴子可以在盲场中对线索进行记忆引导的眼跳，并且可以在盲场中对线索施加自上而下的注意。这些结果表明，通过V1通路的视觉信息可以触发工作记忆，并且该通路中的视觉加工受到自上而下注意的影响。(4)We已经建立了高速视频眼电图来检测小鼠的扫视。刺激SC可诱导小鼠产生眼跳样快速眼动。因此，我们建立了利用小鼠模型研究认知功能分子基础的实验体系。少

In this study, we studied the fundamental structure of the neural circuits controlling saccades and how the activity of the circuits can be modulated in a context dependent manner.(1)At the local circuits level, we clarified the neural mechanism of burst generation of the neurons in the deeper layer of the superior colliculus (SC). We found that the burst is generated via NMDA receptor-mediated transmission and local recurrent network. Release from GABAergic inhibition is essential for the circuit to exhibit burst.(2)We recorded the activities of neurons in the pedunculopontine tegmental nucleus (PPTN), which is the origin of cholinergic input to the SC, during visually guided saccade task. We have found that a group of PPTN neurons showed tonic discharge while monkeys are fixating the fixation point and make saccades. When a large reward volume was expected, the neuron showed higher activity, while when small reward was predicted, the activity was low. These results suggest that these … More PPTN neurons encode predicted reward. Considering that the PPTN neurons project to the dopamine neurons in the substantia nigra, which have been shown to encode reward prediction error, activity of the PPTN neurons were supposed to be used for calculation of reward prediction error at the dopamine neurons.(3)We investigated the saccades of monkeys with unilateral lesion of the primary visual cortex (V1) in monkeys. These monkeys with V1 lesion could perform visually guided saccades to the target presented in the blind field. These monkeys could perform memory guided saccades to the cue in the blind field and could exert top down attention to the cue in the blind field. These results suggested that the visual information through the pathway bypassing the V1 can trigger working memory and the visual processing in the pathway is under the influence of top down attention.(4)We have established the high speed video oculography to detect saccades in mice. Saccade-like rapid eye movements could be induced by SC stimulation in mice. Thus, we have established the experimental system to study the molecular basis of cognitive functions using mice model. Less