1. ELECTROPHYSIOLOGICAL ANALYSIS OF SINGLE NEURONS IN THE CAT'S AMYGDALOID NUCLEAR COMPLEX
1960 年 2 巻 1-2 号 p. 34-48
詳細
1960 年 2 巻 1-2 号 p. 34-48
The experimental subjects consisted of 35 curarized adult cats. With the use of superfine microelectrodes, the single neuronal activities of the principal nuclei of the amygdala were picked up and the reactions to the electrical stimulation given to the temporal tip, midbrain reticular formation, and nonspecific thalamic nuclei were observed.
By the stimulation of the temporal tip, excitatory as well as inhibitory reactions were obtained. In some cases the reversal from inhibition to excitation either during or subsequent to the stimulation was observed. It came to be clear, from the intracellular recording, that EPSPs, the spikes superimposed on them, and IPSPs were generated by each shock, and that both excitatory and inhibitory synaptic contacts are present in one and the same neuron.
With the repetition of the stimulation IPSPs decreased while EPSPs increased; and especially by high frequency stimulation, the membrane potentials were kept above the critical level, and successive spikes were generated. This was suggestive of the reversal mechanism from inhibition to excitation.
By stimulation of the midbrain reticular formation, both excitatory and inhibitory reactions were recognized. The intracellular recording showed the long lasting depolarization due to the summation of EPSPs with the increase of spike firing.
By stimulation of the nonspecific thalamic nuclei both excitatory and inhibitory reactions were also observed, while that of the specific nuclei induced no response. The intracellular records revealed generation of EPSPs and IPSPs. The relation between spike responses and the postsynaptic potentials was discussed.
With reference to the same neurons, stimulations were given to the temporal tip and midbrain- and thalamic reticular systems and consequently the existence of the convergence of the synapses of projections from these regions was ascertained.
When the reactions occuring due to each stimulation of these regions are of the same kind, they were intensified by the combined stimulation; when they were opposite, the reaction caused by the stimulation of temporal tip appeared dominant in most cases.
