Amygdaloid complex modulates neurotransmission from the entorhinal cortex to the dentate gyrus of the rat.

In urethane-anesthetized rats, single-pulse stimulation of the lateral nucleus of the amygdaloid complex evoked field responses in the dentate gyrus. These responses were similar in many respects to those evoked by stimulation of the monosynaptic perforant path input to the dentate, except for their longer latency. Paired-pulse tests revealed a potent facilitation of perforant path-evoked dentate responses by preceding stimulation of the lateral amygdaloid nucleus. These observations indicate a strong amygdaloid influence on cortico-hippocampal neurotransmission and provide some support for recent anatomical descriptions suggesting that the lateral nucleus of the amygdaloid complex projects to the dentate via a disynaptic pathway relaying in the entorhinal cortex.