Context-Dependent Encoding of Fear and Extinction Memories in a Large-Scale Network Model of the Basal Amygdala
PLoS Comput Biol. 2011-03-17; 7(3): e1001104
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1. PLoS Comput Biol. 2011 Mar;7(3):e1001104. doi: 10.1371/journal.pcbi.1001104. Epub
2011 Mar 17.
Context-dependent encoding of fear and extinction memories in a large-scale
network model of the basal amygdala.
Vlachos I(1), Herry C, Lüthi A, Aertsen A, Kumar A.
(1)Bernstein Center for Computational Neuroscience Frieburg, Freiburg, Germany.
The basal nucleus of the amygdala (BA) is involved in the formation of
context-dependent conditioned fear and extinction memories. To understand the
underlying neural mechanisms we developed a large-scale neuron network model of
the BA, composed of excitatory and inhibitory leaky-integrate-and-fire neurons.
Excitatory BA neurons received conditioned stimulus (CS)-related input from the
adjacent lateral nucleus (LA) and contextual input from the hippocampus or medial
prefrontal cortex (mPFC). We implemented a plasticity mechanism according to
which CS and contextual synapses were potentiated if CS and contextual inputs
temporally coincided on the afferents of the excitatory neurons. Our simulations
revealed a differential recruitment of two distinct subpopulations of BA neurons
during conditioning and extinction, mimicking the activation of experimentally
observed cell populations. We propose that these two subgroups encode contextual
specificity of fear and extinction memories, respectively. Mutual competition
between them, mediated by feedback inhibition and driven by contextual inputs,
regulates the activity in the central amygdala (CEA) thereby controlling amygdala
output and fear behavior. The model makes multiple testable predictions that may
advance our understanding of fear and extinction memories.
PMID: 21437238 [Indexed for MEDLINE]