Cell-type-specific recruitment of amygdala interneurons to hippocampal theta rhythm and noxious stimuli in vivo.
Neuron. 2012-06-01; 74(6): 1059-1074
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Neuronal synchrony in the basolateral amygdala (BLA) is critical for emotional
behavior. Coordinated theta-frequency oscillations between the BLA and the
hippocampus and precisely timed integration of salient sensory stimuli in the BLA
are involved in fear conditioning. We characterized GABAergic interneuron types
of the BLA and determined their contribution to shaping these network activities.
Using in vivo recordings in rats combined with the anatomical identification of
neurons, we found that the firing of BLA interneurons associated with network
activities was cell type specific. The firing of calbindin-positive interneurons
targeting dendrites was precisely theta-modulated, but other cell types were
heterogeneously modulated, including parvalbumin-positive basket cells. Salient
sensory stimuli selectively triggered axo-axonic cells firing and inhibited
firing of a disctinct projecting interneuron type. Thus, GABA is released onto
BLA principal neurons in a time-, domain-, and sensory-specific manner. These
specific synaptic actions likely cooperate to promote amygdalo-hippocampal
synchrony involved in emotional memory formation.