Association of ventral striatum monoamine oxidase-A binding and functional connectivity in antisocial personality disorder with high impulsivity A positron emission tomography and functional magnetic resonance imaging study.
Impulsivity is a core feature of antisocial personality disorder (ASPD) associated with abnormal brain function and neurochemical alterations. The ventral striatum (VS) is a key region of the neural circuitry mediating impulsive behavior, and low monoamine oxidase-A (MAO-A) level in the VS has shown a specific relationship to the impulsivity of ASPD. Because it is currently unknown whether phenotypic MAO-A markers can influence brain function in ASPD, we investigated VS MAO-A level and the functional connectivity (FC) of two seed regions, superior and inferior VS (VSs, VSi). Nineteen impulsive ASPD males underwent (11)C harmine positron emission tomography scanning to measure VS MAO-A VT, an index of MAO-A density, and resting-state functional magnetic resonance imaging that assessed the FC of bilateral seed regions in the VSi and VSs. Subjects also completed self-report impulsivity measures. Results revealed functional coupling of the VSs with bilateral dorsomedial prefrontal cortex (DMPFC) that was correlated with VS MAO-A VT (r0.47, p0.04), and functional coupling of the VSi with right hippocampus that was anti-correlated with VS MAO-A VT (r-0.55, p0.01). Additionally, VSs-DMPFC FC was negatively correlated with NEO Personality Inventory-Revised impulsivity (r-0.49, p0.03), as was VSi-hippocampus FC with Barratt Impulsiveness Scale-11 motor impulsiveness (r-0.50, p0.03). These preliminary results highlight an association of VS MAO-A level with the FC of striatal regions linked to impulsive behavior in ASPD and suggest that phenotype-based brain markers of ASPD have relevance to understanding brain function.