Endogenous testosterone modulates prefrontal-amygdala connectivity during social emotional behavior

Area of Science:

• Neuroscience
• Endocrinology
• Social Psychology

Background:

• Testosterone, a steroid hormone, is known to regulate social emotional behavior.
• The specific neural circuits mediating testosterone's influence on human social emotional behavior remain unclear.

Purpose of the Study:

• To investigate the modulatory effects of endogenous testosterone on the neural control of social emotional behavior.
• To identify the brain regions and networks involved in testosterone's influence on social approach-avoidance tasks.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used in healthy male participants.
• Participants performed a social approach-avoidance task involving emotional faces and joystick manipulation.
• Analysis focused on behavioral (reaction times) and neural (brain activity, effective connectivity) responses during affect-congruent and affect-incongruent trials.

Main Results:

• Affect-incongruent trials, requiring overriding automatic responses, led to longer reaction times and increased activity in the ventrolateral prefrontal cortex/frontal pole (VLPFC/FP).
• Lower testosterone levels correlated with greater VLPFC/FP activation during these challenging trials.
• Endogenous testosterone modulated effective connectivity between the VLPFC/FP and the amygdala during affect-incongruent trials.

Conclusions:

• Endogenous testosterone influences social emotional behavior by modulating local prefrontal activity.
• Testosterone also impacts interregional brain connectivity, specifically between the VLPFC/FP and the amygdala.
• These findings elucidate the neuroendocrine mechanisms underlying testosterone's role in social emotional regulation.