ABSTRACT
The prothoracic grooming reflex of the locust is normally inhibited by the rest of the C.N.S. This paper examines the effect of removing the most powerful inhibitory source, the metathoracic ganglion, on the signal flow in and out of the prothoracic ganglion.
Removal of the metathoracic ganglion decreases the number of action potentials entering the prothoracic ganglion; the number of action potentials leaving the prothoracic ganglion increases. Since the recording samples only about 1 % of the axons in the connective, mainly large ones, and since the sample is probably different in different preparations, it is concluded that removal of the input from the metathoracic ganglion causes a general disinhibition of the prothoracic ganglion.
Inhibition of the grooming reflex is probably due to this general inhibition of the ganglion, not to a specific inhibitory connexion with the metathoracic ganglion. It is suggested that the total input to the ganglion may, apart from its specific functions, contribute to a non-specific inhibition, possibly via a ganglionic arousal system.
