title: Increased tone-offset response in the lateral nucleus of the amygdala underlies trace fear conditioning.
abstract: Accumulating evidence suggests that the lateral nucleus of the amygdala (LA) stores associative memory in the form of enhanced neural response to the sensory input following classical fear conditioning in which the conditioned stimulus (CS) and the unconditioned stimulus (US) are presented in a temporally continuous manner. However, little is known about the role of the LA in trace fear conditioning where the CS and the US are separated by a temporal gap. Single-unit recordings of LA neurons before and after trace fear conditioning revealed that the short-latency activity to the CS offset, but not that to the onset, increased significantly and accompanied the conditioned fear response. The increased short-latency activity was evident in two aspects: the number of offset-responsive neurons was increased and the latency of the neuronal response to the CS offset was shortened. On the contrary, changes in the firing rate to either the onset or the offset were negligible following unpaired presentations of the CS and US. In sum, our results suggest that increased synaptic efficacy in the CS offset pathway in the LA might underlie the association between temporally distant stimuli in trace fear conditioning.
authors.affiliation: Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology and Neuroscience, Duke University, Durham, NC, USA.
authors.forename: Namsoo
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology, University of Washington, Seattle, WA, USA.
authors.forename: Mi-Seon
authors.initials: MS
authors.lastname: Kong
authors.affiliation: Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea.
authors.forename: Kyeong Im
authors.initials: KI
authors.lastname: Jo
authors.affiliation: Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea; Department of Psychology, University of Washington, Seattle, WA, USA.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Psychology, Korea University, 5-1, Anam-dong, Seongbuk-gu, Seoul, Republic of Korea. Electronic address: j-schoi@korea.ac.kr.
authors.forename: June-Seek
authors.initials: JS
authors.lastname: Choi
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D066272:Basolateral Nuclear Complex / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology*; D004597:Electroshock; D005239:Fear / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D013997:Time Factors
keywords: Amygdala; Single unit recording; Synaptic plasticity; Trace fear conditioning