一次運動野への入力様式から見た前頭前野の体部位再現

抄録

The patterns of the multisynaptic inputs from the prefrontal areas to the primary motor cortex (MI) were studied by means of retrograde transsynaptic transport of rabies virus. Previous studies revealed that transsynaptic labeling of 1st-, 2nd-, and 3rd-order neurons with the virus occurs at 2, 3, and 4 days postinjection periods. In the present study, the virus was injected into the hindlimb, proximal forelimb, or distal forelimb representation of the MI of macaque monkeys, and, 4 days after the injection, the distribution of labeled neurons was examined in the prefrontal cortex. After the viral injection into the hindlimb representation, prefrontal labeling was observed mainly in the medial prefrontal cortex that is located on the medial wall of the hemisphere. After the injection into the proximal forelimb representation, a large number of neurons were labeled in the dorsolateral prefrontal cortex, mainly in its dorsal sector. After the injection into the distal forelimb representation, very dense labeling was observed in the ventral sector of the dorsolateral prefrontal cortex. The present results suggest that there may be a somatotopic organization in the prefrontal cortex. Functional implications for this organization will be discussed in terms of intracortical inputs to the prefrontal areas. [Jpn J Physiol 55 Suppl:S185 (2005)]