Abstract
To elucidate the mode of interhemispheric neural connection and cooperation of the two neurons of bilateral somatosensory cortices, cross-correlation analysis were executed for approximately 300 neurons at the forelimb projection areas of 3a of the cats. Neuron data were collected during the spontaneous activity. Cat were anesthetized with Ketamine hydrochloride and sometimes immobilized by Gallamine triethiodide. Neuron pairs were selected having the following properties. 1) responsive to the same electric stimuli with the short latency(less than 10msec) of the same pair stimulation electrodes inserted in the corpus callosum. 2) selected at the optimal recording site of the evoked potentials to the radial nerve stimulation. Neurons pair could be categorized into three groups. 1) Most numerously recorded pairs having the common input neuron. 2)Second numerous pairs with inhibitory feature in cross correlation histogram(CCH). Probably their connection was composed of transcallosal excitatory neuron and local inhibitory neuron.3) Neuron pairs with excitatory feature in CCH were very rarely observed (less than 5%). Although we could not deny a possibility of the anesthetic effect or sampling bias of the selected neurons, these results might indicate that callosal neurons act rather suppressive than excitatory to neurons at the symmetrical position in the contra lateral somatosensory cortex on the spontaneous condition. [Jpn J Physiol 54 Suppl:S192 (2004)]
