Abstract
We have reported that tongue and jaw movements in cats were controlled by pyramidal neurons in area P (the lateral wall of the presylvian sulcus) (Hiraba et al., 1993; Hiraba et al., 2000; Hiraba and Sato, 2005a). Namely, many mastication-related neurons (MRNs) that were recorded in the area P, related to movements of jaw and tongue, and intracortical microstimulation at MRN recording sites evoked tongue protrusion and jaw-opening without deviation. In comparison with the normal cat, cats with lesion in the unilateral area P produced the abnormal tongue protrusion and wide jaw-opening during mastication. Furthermore, callosal connection of bilateral area P was examined by the WGA-HRP. Thus, I assume from these results that pyramidal cells with the commissural fibers may exist between bilateral area P. To investigate these suggestions, changes in orofacial behaviors and in the regional cerebral blood flow (rCBF) of the unilateral area P during mastication were examined after each injection of GABA agonist (1.0μg/μl muscimol, .2μl) and GABA antagonist (1.0μg/μl bicucurine, 4μl) into the contralateral area P. Based on these findings, the adequate condition of tongue and jaw movements during licking may be conducted by GABAergic interneuron between the commissural fiber and pyramidal neuron. [Jpn J Physiol 55 Suppl:S179 (2005)]
