LeDoux Lab 2013 SfN Abstracts
 
Program#/Poster#: 860.12/JJJ7
Title: Short-term plasticity and noradrenergic modulation in the lateral amygdala
Location: Halls B-H
Presentation Time: Wednesday, Nov 13, 2013, 4:00 PM - 5:00 PM
Authors: *A. E. FINK1, M. HOU1, J. E. LEDOUX1,2;
1Ctr. for Neural Sci., New York Univ., New York, NY; 2Nathan S. Kline Inst. for Psychiatric Res., Orangeburg, NY
Abstract: Pavlovian threat conditioning (PTC) depends on convergence of auditory and somatosensory inputs in the lateral nucleus of the amygdala (LA), and modulation of these inputs by noradrenergic transmission. LA also receives input from other areas, including prefrontal cortex and hippocampus, and some of these inputs are electrophysiologically coupled to LA neurons at different frequencies during the acquisition, consolidation and extinction of PTC. Long-term plasticity (occurring over minutes to hours) at sensory inputs to the LA is one potential mechanism underlying PTC. Less is known about short-term plasticity (STP) in the LA, however. STP (temporary changes lasting for milliseconds to tens of seconds) could shape the responsiveness of neurons to inputs arriving from different afferents or at different frequencies and could thus influence more permanent changes related to memory formation. Nevertheless, little is known about how STP functions at different inputs to LA, or how neuromodulators such as norepinephrine impact STP. Using electrophysiological recordings from acute slices of the adult mouse amygdala, we measured the response of LA principal cells to trains of stimulation at theta (5 Hz), beta (30 Hz) or gamma (100 Hz) frequencies at either cortical or subcortical inputs. We also tested the hypothesis that beta- and alpha-adrenergic receptor agonists would impact STP in a frequency- and input-specific manner. We found that, indeed, synaptic transmission is differentially modulated between the two sets of inputs at 5 Hz, but not at higher frequencies. Specifically, subcortical inputs exhibited an enhanced inhibition over the course of 5-Hz stimulation. In agreement with previous data, we found that beta-adrenergic modulation enhanced subcortical inputs relative to cortical inputs through a putative decrease in inhibition. This modulation was also most notable at 5Hz. Alpha1-adrenergic receptor activation also produced moderate enhancement of excitatory synaptic transmission at both inputs during 5 Hz stimulation, but not at higher frequencies. Together, these results indicate that cortical and subcortical inputs to the LA exhibit different forms of STP at physiologically relevant frequencies, and that these short-term changes are also differentially modulated by norepinephrine.

Support: Sevier Laboratories