Psychopaths Show Enhanced Amygdala Activation during Fear Conditioning

Area of Science:

• Neuroscience
• Psychiatry
• Psychology

Background:

• Psychopathy is a personality disorder with emotional deficits and impulsivity.
• It's often divided into primary and secondary subtypes, with primary linked to fearlessness and secondary to other factors.
• Previous research suggested a "low-fear model" of psychopathy, implicating amygdala dysfunction, but methodological limitations exist.

Purpose of the Study:

• To investigate brain activity during fear conditioning in primary and secondary psychopathy.
• To test the validity of the "low-fear model" of psychopathy.
• To differentiate neural mechanisms underlying primary versus secondary psychopathy.

Main Methods:

• Used BOLD imaging to measure brain activity during Pavlovian fear conditioning.
• Included primary psychopaths, secondary psychopaths, and non-psychopathic control subjects.
• Focused on amygdala and anterior cingulate cortex (ACC) activity.

Main Results:

• Primary psychopaths exhibited normal fear expression, contrary to the low-fear model.
• Psychopaths showed greater differential BOLD activity in the amygdala compared to controls.
• Distinct ACC activity patterns were observed: primary psychopaths showed enhanced fear expression, while secondary psychopaths showed fear inhibition.

Conclusions:

• The "low-fear model" is challenged, as primary psychopaths do not necessarily exhibit low fear.
• Observed fear deficits in psychopathy may be specific to the secondary subtype.
• Neural activity in the amygdala and ACC differentiates psychopathy subtypes and challenges existing models.