Synaptic plasticity in fear conditioning circuits: induction of LTP in the lateral nucleus of the amygdala by stimulation of the medial geniculate body.

Electrical stimulation of the medial geniculate body in the anesthetized rat produces an evoked potential in the lateral nucleus of the amygdala. The potential varies in amplitude with stimulus intensity and reaches peak amplitude in 8.5 msec on the average. High-frequency stimulation of the pathway produces long-lasting increases in the amplitude and slope of the potential. These robust and enduring experience-dependent modifications in neural transmission occur in a pathway known to be involved in the formation of emotional memories and may offer a means for examining the cellular mechanisms of emotional learning, as well as a new approach to questions concerning the relevance of long-term potentiation to normal mnemonic processes.