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This Article Full Text Full Text (PDF) All Versions of this Article: 102/3/1379    most recent 00438.2009v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Crane, J. W. Articles by Sah, P. PubMed PubMed Citation Articles by Crane, J. W. Articles by Sah, P.

Oscillations in the Basolateral Amygdala: Aversive Stimulation Is State Dependent and Resets the Oscillatory Phase

Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia

Submitted 21 May 2009; accepted in final form 24 June 2009

Abstract

Slow oscillations (<1 Hz) in neural activity occur during sleep and quiet wakefulness in both animals and humans. Here we show that in urethan-anesthetized animals, neurons in the basolateral amygdala in vivo display a slow oscillation between resting membrane potential (down-state) and depolarized potentials (up-states) occurring at a frequency of 0.3 Hz. This oscillation is insensitive to the holding potential and continues unabated under voltage clamp, indicating that up-states are synaptically driven. Somatosensory stimulation (footshock) delivered during the down-state evoked an all-or-none transition into an up-state. When delivered during down-states, footshocks triggered up-states and reset the phase of the neural oscillation, effectively synchronizing activity in the basolateral amygdala. This phase reset was reproduced by posterior thalamus stimulation, confirming that it was mediated by aversive sensory input. In contrast, a footshock delivered during the up-state was ineffective in stimulating BLA neurons. We conclude that oscillatory activity in the basolateral amygdala is driven by ensembles of cortical neurons. These ensembles gate the response of amygdala neurons to aversive stimulation in a state-dependent manner. Aversive stimulation is effective when the network is in the down-state but ineffective when the network is in an up-state.