infralimbic cortex
{{Short description|Brain region of tonic inhibition of fear}}
{{Infobox brain
| Name = Infralimbic cortex
| Latin = Cortex infralimbicus
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The infralimbic cortex (IL) is a cortical region in the ventromedial prefrontal cortex which is important in tonic inhibition of subcortical structures and emotional responses, such as fear."Microstimulation reveals opposing influences of prelimbic and infralimbic cortex on the expression of conditioned fear." Learn. Mem., Vol. 13, No. 6. (1 November 2006), pp. 728-733. Ivan Vidal-Gonzalez, Benjamin Vidal-Gonzalez, Scott L Rauch, Gregory J Quirk.
Structure
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Connectivity
=Primates=
GABAergic neurons within the amygdala, known as intercalated (ITC) cells, receive a strong projection from the IL medial prefrontal cortex (mPFC) in primates.Chiba et al., 2001; Ghashghaei and Barbas, 2002. ITC cells are thought to play a role as the 'off switch' for the amygdala, inhibiting the amygdala's central nucleus output neurons and its basolateral nucleus neurons.Quirk, G.J. & Mueller, D. (2007). Neural mechanisms of extinction learning and retrieval. Neuropsychopharmacology Reviews, 1-17. Further, it has been shown that electrical stimulation of IL reduces conditioned fear and strengthens extinction memory{{clarify|reason=no explanation, context, or Wikipedia article defining 'extinction memory'|date=June 2015}}, explaining cortical control over extinction processes,{{clarify|reason='extinction' link does not explain this use of expression 'extinction processes'|date=June 2015}} one of the simplest forms of emotional regulation.
=Rodents=
Amygdala ITC cells receive strong projection from the IL mPFC in rodents as well.McDonald et al., 1996.