Brain potentials related to the human penile erection

Institute of Medical Psychology,University of Rostock, Rostock, GermanyThe aim of this study was to elucidate the brain processes preceding penile responses.Electroencephalographic (EEG) potentials and penile circumference were recorded simultaneouslywhile male subjects wereexposedtovisualsexual stimuli (VSS). The trialsweresorted by the penileresponse of the subjects (erection, maintenance or detumescence). The corresponding EEGrecordings were then subjected to independent component analysis. We found that 200ms afterVSS onset brain potentials differ according to the genital response to follow. Whereas earlyposterior negativity (EPN) was predominantly related to erection and maintenance, P3-like activitywas found to precede detumescence. EPN indicates a more ‘emotional’ processing state of the brain,whereas P3-like activity related to detumescence indicates a more ‘cognitive’ processing state. Thelatter is assumed to reflect activity of the locus coeruleus–norepinephrine system. Further researchshould evaluate the contribution of P3-related brain activity to psychogenic erectile dysfunction.International Journal of Impotence Research (2009) 21, 292–300; doi:10.1038/ijir.2009.31;published online 9 July 2009Keywords: phallometry; EEG; ICA