Synaptic facilitation requires paired activation of convergent pathways in the neocortex

Abstract

In associative learning, the activated neurons undergo a variety of concomitant functional alterations, increases or decreases of firing activity, and modifications of membrane potential or resistance and of synaptic responsiveness. Synaptic transmission which can be strengthened only when there is paired activity in 2 pathways is of particular interest in relation to mechanisms for associative learning. For the neocortex, there are few observations of the plastic changes, induced by conditioning procedures, in the effectiveness of individual synapses. Various regimes with joint stimulations of convergent excitatory pathways onto intracellularly recorded neurons in the motor cortex of the cat result in synaptic facilitation lasting for up to 30 min.