ELEMENTARY TRANSCALLOSAL CONNECTIONS OF THE RABBIT SENSORIMOTOR CORTEX

Antidromic responses of 2 callosal neurons to a local electrical stimulation of the rabbit sensorimotor cortex may be recorded simultaneously with 1 microelectrode in the homotopic cortical area. In such recording conditions the relative amplitude of extracellularly recorded action potentials of the 2 neurons is determined primarily by the distance between these neurons and the electrode''s tip. In response to the stimulation of the symmetrical area transcallosal monosynaptic excitation of the callosal neuron may occur; 2 callosal neurons may excite monosynaptically 1 and the same recorded neuron. The existence of clusters or columns, formed jointly by the bodies and terminals of callosal neurons was suggested. A functional interconnection between symmetrical clusters or columns may exist, in particular a positive feedback.