Functional significance of cortico-subthalamic pathway

How the motor-related cortical areas modulate the activity of the output nuci of the basal ganglia is an important issue for understanding the mechanisms of motor control by the basal ganglia。在目前的研究中，使用唤醒猴子，对初级电机和初级细胞传感器的前区域的活动的全球pallidus （GP）神经元（特别是亚塔拉米核（STN）介导的电刺激的多重效应，已被表征。医学刺激诱导了一种早期的、短暂的延迟刺激，由神经元的两种外部和内部部分的抑制和延迟刺激引起。这也是一种早期的、短暂的延迟兴奋，由延迟兴奋和STN神经元中的抑制引起的。在GP神经元中预先准备的STN神经元的早期兴奋。Blockade of STN neuronal activity by muscimol （GABA D2A y D2 receptor agonist） injection resulted in abolishment of both the early and late excitations evoked in GP neurons by cortical stimulation。在同一时间，GP神经元递减的自发放电率，GP神经元成为突出者的尖峰群体之间的停顿，以及初始模式成为常规。注射CPP （NMDA受体拮抗剂），但不是NBOX （非NMDA受体拮抗剂），在GP神经元的早期和后期刺激中受到STN的关注，建议皮质亚淀粉传输主要由NMDA受体介导。Interference with the pallido-subthalamic transmission by bicuculline （GABA-D2A-D2 receptor antagonist） injection into the STN made the inhibition distinct without affecting the early excitation。目前的结果表明，Cortico-subthalamo-pallidal通路输送从与电机有关的轨道区域产生强有力的异常效应，使GP在短时间条件下的影响通过断层输送。

How the motor-related cortical areas modulate the activity of the output nuclei of the basal ganglia is an important issue for understanding the mechanisms of motor control by the basal ganglia. In the present study, by using awake monkeys, the polysynaptic effects of electrical stimulation in the forelimb regions of the primary motor and primary somatosensory cortices on the activity of globus pallidus (GP) neurons, especially mediated by the subthalamic nucleus (STN), have been characterized. Cortical stimulation induced an early, short-latency excitation followed by an inhibition and a late excitation in neurons of both the external and internal segments of the GP. It also induced an early, short-latency excitation followed by a late excitation and an inhibition in STN neurons. The early excitation in STN neurons preceded that in GP neurons. Blockade of STN neuronal activity by muscimol (GABAィイD2AィエD2 receptor agonist) injection resulted in abolishment of both the early and late excitations evoked in GP neurons by cortical stimulation. At the same time, the spontaneous discharge rate of GP neurons decreased, pauses between the groups of spikes of GP neurons became prominent, and the firing pattern became regular. Injection of CPP (NMDA receptor antagonist), but not NBOX (non-NMDA receptor antagonist), into the STN attenuated the early and late excitations in GP neurons, suggesting that cortico-subthalamic transmission is mediated mainly by NMDA receptors. Interference with the pallido-subthalamic transmission by bicuculline (GABAィイD2AィエD2receptor antagonist) injection into the STN made the inhibition distinct without affecting the early excitation. The present results indicate that the cortico-subthalamo-pallidal pathway conveys powerful excitatory effects from the motor-related cortical areas to the GP with shorter conduction time than the effects conveyed through the striatum.