Participants
excessive head motion (mean total displacement, neurological or psychiatric disease
We only recruited male volunteers to avoid problems that could arise with unknown pregnancies in female volunteers. Twenty-six healthy men participated (mean age 26.0 ± 4.1 years, range 20–38 years). They were right-handed and had normal or corrected-to-normal vision. None of them had a history of neurological or psychiatric disease. All of them were free of medication. Four participants were excluded because of excessive head motion (mean total displacement >1.5 mm, 