Physiology & behavior
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Prior research [van Honk J, Tuiten A, Verbaten R, van den Hout M, Koppeschaar H, Thijssen J, de Haan E. Correlations among salivary testosterone, mood, and selective attention to threat in humans. Horm Behav 1999;36(1):17-24; van Honk J, Tuiten A, Hermans E, Putman P, Koppeschaar H, Thijssen J, Verbaten R, van Doornen L. ⋯ Morning T predicted greater Stroop-like interference to sub-threshold anger faces, as well as attentional orienting away from sub-threshold anger faces. These effects were not present for joy faces or for supraliminal anger faces. T may generally decrease aversion to threatening stimuli, and/or may specifically facilitate approach towards signals of dominance challenge.
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Physiology & behavior · Feb 2007
On again, off again effects of gonadectomy on the acoustic startle reflex in adult male rats.
Numerous studies have shown sex and/or estrous cycle differences in the acoustic startle reflex (ASR) and its prepulse inhibition (PPI) in humans and animals. However, few have examined the effects of hormone manipulations on these behaviors. This study paired gonadectomy (GDX) in adult male rats with testing for ASR and PPI at 2, 4, 9, 16, 23, 30 and 37 days after surgery. ⋯ However, while responses in GDX rats given testosterone were similar to those of controls, ASR in estradiol- and to a lesser extent in dihydrotestosterone-treated GDX rats were typically lower than in controls. This may suggest that hormone modulation of the ASR requires synergistic estrogen and androgen actions. In the male brain where this can be achieved by local steroid metabolism, the enzymes responsible, e.g., aromatase, could help identify loci in the startle circuitry that may be especially relevant for the hormone modulation observed.