UNITARY RESPONSES TO AFFERENT VOLLEYS IN AMYGDALOID COMPLEX

Abstract

The unitary response to afferent volleys was examined in the amygdala of curarized cats by means of capillary micro-electrodes. All the stimuli tested showed themselves capable of modifying the activity of amygdaloid units. However, the number of units responding to sciatic excitation and to touch of the skin was by far the greatest. An also large number of units was influenced by stretching of the gastrocnemius or by single shocks to the olfactory bulb. Few reacted to click or flash stimuli or to excitation of the midbrain, vagus or tooth pulp. The convergence of different sensory modalities upon single units was outstanding, the most frequent type encountered being that of sciatic and olfactory volleys. The most frequent type of response consisted in an increase in the rate of unitary firing. The functional significance of these findings is discussed in relation to comparative and developmental data.