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Updated: Aug 5, 2026
11:13
Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices
Published on: April 5, 2016
Medial Prefrontal Cortex Innervation of the Basal Forebrain Regulates Behavioral Activation with Prelimbic and
Mert Genc1, Cem Sevinc1, Bahar Yuksel1
1Behavioral Neuroscience Laboratory, Department of Psychology, Boğaziçi University, 34342 Istanbul, Turkey.
Summary
The medial prefrontal cortex (mPFC) controls behavior via basal forebrain (BF) projections. Distinct mPFC pathways to the BF differentially regulate fear, motivation, and valence, revealing circuit mechanisms for affective control.
Area of Science:
- Neuroscience
- Behavioral Neuroscience
- Systems Neuroscience
Background:
- The medial prefrontal cortex (mPFC) regulates affective and motivational behaviors.
- Its projections to the basal forebrain (BF) are crucial but poorly understood.
- Distinct mPFC subregions (PrL, IL) have unique roles in behavior.
Purpose of the Study:
- Investigate the functional contribution of mPFC projections to the BF.
- Determine the roles of prelimbic (PrL) and infralimbic (IL) pathways in affective behaviors.
- Characterize the neural circuits underlying mPFC-BF interactions.
Main Methods:
- Viral tracing and neural activity mapping in rats.
- Pathway-specific optogenetic activation and manipulation.
- Behavioral assays including conditioned fear and place preference/avoidance.
- Molecular characterization of neuronal populations and synapses.
Main Results:
- Both PrL and IL projections to BF are recruited by stress.
- Activation of BF-projecting mPFC neurons reduces freezing and causes avoidance.
- IL-BF pathway activation increases activity, suppresses fear, and promotes place preference.
- PrL-BF pathway activation causes place avoidance without affecting activity or fear responses.
- BF-projecting mPFC neurons target inhibitory neurons in the ventral pallidum.
Conclusions:
- The basal forebrain is a key target for mPFC control of affective functions.
- IL-BF pathway mediates positive valence, behavioral activation, and fear suppression.
- PrL-BF pathway conveys aversive signals and drives avoidance.
- These findings reveal dissociable circuit mechanisms for affective regulation by mPFC subregions.
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