Modification of synaptic efficiency, experiments in blatta orientalis

Abstract

The efficiency of synapt ic transmission in a nervous pathway--metathoracic ganglia from the cockroach--can be increased by various experimental situations, i.e., removal, immobilization or denervation of the forelegs of insects in ventral position. Leg immobilization with the insect in supine position by itself determines a minor increase which is not enhanced by removal or denervation of the forelegs. Under these conditions, the insects are able to hold their antennae with a midleg immediately after any of the leg treatments. On the other hand, if the insects are allowed to be in ventral position they can hold their antennae with a midleg only when they reach the ability to stand on the remaining three legs. During the time period needed to acquire this ability, the insects make repeated and spontaneous motor effects. The increase in synaptic efficiency observed and the achievement of the insect's ability to stand on three legs occur at about the same time. These observations suggest that the self-training determines the synaptic modifications which in turn could be related to the "learnt" behavioral reaction.