Relation between the secondary optic fibre system and the centrencephalic system.

Abstract

The existence of a fibre connection from the deep layers of the dorsal lateral geniculate body to the lateral posterior thalamic nucleus has been confirmed with histological methods in the cat. A fibre tract from the lateral posterior thalamic nucles to the ventral anterior thalamic nucleus and to the central lateral thalamic neucleus has been demonstrated. Electrical stimulation of the lateral posterior thalamic nucleus resulted in ipsilateral head movements, loss of posture, jerking and fully developed seizures with loss of bladder control, and with spikewave activity in the EEG in the freely moving cat. Electrical stimulation of anterior thalamic regions at the ventral anterior thalamic nucleus and at the central lateral thalamic nucleus produced only some jerking of the legs, which stopped on termination of the stimulus and was never combined with loss of bladder control. Electrical stimulation of the dorsal lateral geniculate body and of the rostral colliculus and of the nucleus cuneiformus confirmed earlier results from the literature. The lateral posterior thalamic nucleus is thought to be a major part of the centrencephalic epileptic system with a direct connection to the occipital cortex and with an indirect connection, through the anterior thalamic nuclei, to the frontal cortex.