The ventromedial prefrontal cortex (vmPFC) is a part of the prefrontal cortex in the mammalian brain.The ventral medial prefrontal is located in the frontal lobe at the bottom of the cerebral hemispheres and is implicated in the processing of risk and fear.he prefrontal cortex is also physically effected by cocaine use. Chronic use has been shown to lead to a decrease in the amount of gray matter in the ventromedial prefrontal cortex. The decrease in gray matter and effect on behavior is analogous to a person having lesions throughout their medial prefrontal cortex.