抄録
To investigate motor cortical inputs to the subthalamic nucleus (STN), we examined the responses of the STN neurons to the stimulation of the primary motor cortex (M1) and the supplementary motor area (SMA). Stimulating electrodes were chronically implanted in the orofacial, forelimb and hindlimb regions of the M1 and the forelimb and hindlimb regions of the SMA in a Taiwan macaque (Macaca cyclopis). Among 144 STN neurons with cortical inputs, about 40% neurons responded to both M1 and SMA stimulation, and most of them responded to the stimulation of multiple body parts. On the other hand, other 60% neurons responded exclusively to either M1 or SMA stimulation, and most of them responded to the stimulation of a single body part. Neurons responding mainly to the M1 stimulation were distributed in the dorsolateral part of the STN, while neurons responding mainly to the SMA stimulation were found mainly in the ventromedial part. In the M1 domain of the STN, neurons responding to the stimulation of the orofacial, forelimb and hindlimb regions were represented in its lateralmost, central and medial parts, respectively. In the SMA domain, neurons receiving inputs from the forelimb region were located more medially than those receiving inputs from the hindlimb region. These somatotopical arrangements agree well with previous anatomical studies (Nambu et al., 1996). The present study clearly showed that cortical inputs from the M1 and SMA to the STN are somatotopically organized in spite of considerable convergent inputs from these cortical areas. [J Physiol Sci. 2007;57 Suppl:S159]
