Here, we aim to investigate the influence of sexual urge on motor evoked potentials.
24 heterosexual healthy men viewed single stimuli of naked women or men genitals covered with black bars. Control stimuli were generated by Fourier transformation of these stimuli. Each stimulus category was shown 60 times without repetition of one stimulus. Subjects had to judge if they want to see the person naked. Subjects received a transcranial magnetic resonance pulse during the motor preparation phase. Ratings with respect to emotional palatableness, sexual arousal, and sexual motivation were done after the MEP paradigm on a five-point scale.
Heterosexual men showed increased motor evoked potentials for viewing female in contrast to male sexual stimuli. There were no significant correlations of the ratings with motor evoked potentials.
Increased motor cortex excitability might be not only related to the attractiveness of the female pictures but also to the aversiveness of the male pictures. Data with respect to homosexual subjects might add further hints for motor cortex excitability as biomarker for sexual urge.