Abstract
Background Previous research suggests that testosterone (T) plays a key role in shaping competitive and aggressive behavior in humans, possibly by modulating threat-related neural circuitry. However, this research has been limited by the use of T augmentation that fails to account for baseline differences and has been conducted exclusively in women. Thus, the extent to which normal physiologic concentrations of T affect threat-related brain function in men remains unknown. Methods In the current study, we use a novel two-step pharmacologic challenge protocol to overcome these limitations and to evaluate causal modulation of threat- and aggression-related neural circuits by T in healthy young men (n = 16). First, we controlled for baseline differences in T through administration of a gonadotropin releasing hormone antagonist. Once a common baseline was established across participants, we then administered T to within the normal physiologic range. During this second step of the protocol we acquired functional neuroimaging data to examine the impact of T augmentation on neural circuitry supporting threat and aggression. Results Gonadotropin releasing hormone antagonism successfully reduced circulating concentrations of T and brought subjects to a common baseline. Administration of T rapidly increased circulating T concentrations and was associated with heightened reactivity of the amygdala, hypothalamus, and periaqueductal grey to angry facial expressions. Conclusions These findings provide novel causal evidence that T rapidly potentiates the response of neural circuits mediating threat processing and aggressive behavior in men.
Original language | English (US) |
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Pages (from-to) | 324-331 |
Number of pages | 8 |
Journal | Biological Psychiatry |
Volume | 76 |
Issue number | 4 |
DOIs | |
State | Published - Aug 15 2014 |
Keywords
- Aggression
- amygdala
- androgens
- anger
- emotion
- fMRI
- testosterone
ASJC Scopus subject areas
- Biological Psychiatry