LONG-TERM SYNAPTIC POTENTIATION IN THE AMYGDALA

The manner in which the circuitry of the amygdala computes its suspected mnemonic has been a mystery, partly cellular analysis. Here we report in vitro methods and results that may help elucidate cellular learning mechanisms in amygdala neurons. The amygdala brain slice preparation was combined with the single‐electrode clamp (sEC) technique for intracellular analysis of membrane properties and synaptic responses. With respect to the active and passive membrane properties, we found considered diversity among the population of cells that were sampled in the lateral and basolateral nuclei (n = 85). Synaptic inputs to these neurons were studied by stimulating the external capsule (EC), which was shown to produce a complex response that typically consisted of an excitatory followed by an inhibitory component. Based on serval criteria, the excitatory component apperred to reflect a monosynaptic connection from the EC. One immediate goal was to discover whether the excitatory component displays the phenomenon of long‐term potentiation (LTP)–a persistent increase in synaptic stimulation. Indeed, we found that high‐frequency (100 Hz) stimulation of the EC induced LTP in 80% of the cells from which suitable recordings were obtained (n= 20). This finding of LTP in the amygdala is significant in regard to current effort to explore linkages between this use‐dependent form of synaptic plasticity and rapid kinds of associative learning. Copyright © 1990 Wiley‐Liss, Inc.