Double cortical control acting upon activities of intralaminar thalamic cells

RESUMO

We report the effects exertec by the cortex upon the intralaminar thalamic nuclei, as revealed by blockade of the cortex with spreading depression in awake rats. Extracellular recordings of spontaneuous activity were made simultaneusly at thalamic and cortical sites. The effect of peripheral receptive field stimulation was to decrease activity of intralaminar thalamic cells. Cortical recordings revealed the cortical regions affected by spreading depression. Two type of cells were identified depending on the changes in their sensorial responses during the cortical spreading depression propagation. The first exhibited a tonic facilitating cortical control when the cortical spreading depression was located at a 8.0 to 10.0. The second type exhibited a disappearance of the sensorial responses when cortical spreadinf depression was a located at 4.0 to a 8.0 and also displayed the tonic facilitating control. This indicated that two different identifies cortical regions influenced the thalamic activity