%0 Journal Article
%T Stimulation of Perforant Path Fibers Induces LTP Concurrently in Amygdala and Hippocampus in Awake Freely Behaving Rats
%A J. Harry Blaise
%A Rachel A. Hartman
%J Neural Plasticity
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/565167
%X Long-term potentiation (LTP) which has long been considered a cellular model for learning and memory is defined as a lasting enhancement in synaptic transmission efficacy. This cellular mechanism has been demonstrated reliably in the hippocampus and the amygdala¡ªtwo limbic structures implicated in learning and memory. Earlier studies reported on the ability of cortical stimulation of the entorhinal cortex to induce LTP simultaneously in the two sites. However, to retain a stable baseline of comparison with the majority of the LTP literature, it is important to investigate the ability of fiber stimulation such as perforant path activation to induce LTP concurrently in both structures. Therefore, in this paper we report on concurrent LTP in the basolateral amygdala (BLA) and the dentate gyrus (DG) subfield of the hippocampus induced by theta burst stimulation of perforant path fibers in freely behaving Sprague-Dawley rats. Our results indicate that while perforant path-evoked potentials in both sites exhibit similar triphasic waveforms, the latency and amplitude of BLA responses were significantly shorter and smaller than those of DG. In addition, we observed no significant differences in either the peak level or the duration of LTP between DG and BLA. 1. Introduction Long-term potentiation (LTP), a form of synaptic plasticity, is an activity-dependent increase in synaptic strength induced by high frequency stimulation of afferent pathways [1]. Owing to its associativity, specificity, and persistence properties LTP is now widely considered as a cellular model for learning and memory [2¨C5]. Much attention in LTP research has focused on the hippocampus which is thought to be involved in learning and memory processes. More recently, the amygdala has enjoyed renewed interest due to its implication in modulating synaptic plasticity in the hippocampus, the prefrontal cortex, and the anterior cingulate cortex [6¨C9] and its involvement in memory consolidation and emotional memories [10¨C17]. Emotional memories, including fear conditioning and extinction, are thought to be mediated by the amygdala [10, 18¨C21]. The basolateral amygdala (BLA) in particular has been shown to be extensively connected with cortical and subcortical structures involved in memory and emotion, notably the hippocampal formation, the striatum, the prefrontal cortex, the entorhinal cortex, the association cortices, and the thalamus, among others [22, 23]. As a result, the BLA is thought to play a crucial role in psychophysiological responses to emotionally salient events or sensory stimuli
%U http://www.hindawi.com/journals/np/2013/565167/