ex-vivo-optogenetic-dissection-of-fear-circuits-in-brain-slices

<em>Ex Vivo</em> Optogenetic Dissection of Fear Circuits in Brain Slices

Optogenetic approaches are now widely used to study the function of neural populations and circuits by combining targeted expression of light-activated ...

Max Planck Florida Institute for Neuroscience

Increasing evidence suggests that parallel plastic processes in the amygdala involve inhibitory elements to control fear and extinction memory. GABAergic medial paracapsular intercalated cells (mpITCs) are thought to relay activity from basolateral nucleus (BLA) and prefrontal cortex to inhibit central amygdala output during suppression of fear. Recently, projection diversity and differential behavioral activation of mpITCs in distinct fear states suggest additional functions. Here, we show that mpITCs receive convergent sensory thalamic and cortical inputs that undergo fear learning-related changes and are dynamically modulated via presynaptic GABAB receptors recruited by GABA released from the mpITC network. Among mpITCs, we identify cells that inhibit but are also mutually activated by BLA principal neurons. Thus, mpITCs take part in fear learning-modulated feedforward and feedback inhibitory circuits to simultaneously control amygdala input and output nuclei. Our findings place mpITCs in a unique position to gate acquired amygdala-dependent behaviors via their direct sensory inputs.

Douglas Asede

Max Planck Florida Institute for Neuroscience

Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices