ABSTRACT
PURPOSE: The objectives of this study are to identify the brain centers whose activity changes are related to sexually arousing visual stimuli and to identify the difference between young and middle-aged males by mapping the brain activity with using blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI). MATERIALS AND METHODS: Ten young heterosexual, right handed males with normal sexual function (mean age: 27 years, age range: 24 to 31) and ten middle-aged heterosexual, right handed males with normal sexual function (mean age: 52 years, age range: 46 to 55) were enrolled into this study. Real-time visual stimulation was performed with the subjects alternatively viewing erotic and non-erotic films to identify the activated brain regions associated with sexual response. Assessments with using a five-point scale were determined after visual stimulation to evaluate the subjective sexual arousal. Brain activity was mapped by performing BOLD-fMRI on a 1.5T MR scanner. After functional scanning, the high-resolution data was analyzed with the SPM analyzing program; the significance of activation was set at p<0.01 or p<0.001. RESULTS: The parietal lobe, frontal lobe, cingulate gyrus, caudate nucleus, thalamus and hypothalamus were noted as the areas of activation specifically associated with viewing the erotic film segments by the young males. For the middle-aged males, these areas were the parietal lobe, frontal lobe, right temporal lobe, cingulate gyrus and caudate nucleus. The thalamus and hypothalamus were activated in only the young males. CONCLUSIONS: We suggest that the non-activation of the hypothalamus and thalamus in middle-aged males may be associated with the lesser physiological arousal in response to the erotic visual stimuli. The non-invasive visualization of the central nervous system by functional MRI in healthy males has shown the possibility for evaluating the neuroanatomy of the brain that is associated with sexual arousal and its clinical application by comparing young and middle-aged males.