title: Brain processing of audiovisual sexual stimuli inducing penile erection: a positron emission tomography study.
abstract: OBJECTIVE
  Penile erection is dependent on commands from the central nervous system. Although basic studies of animals and neuroimaging studies of humans have been conducted to identify key brain regions associated with sexual arousal, to our knowledge no reliable studies of the first excitation phase of sexual arousal leading to penile erection have been reported.
  
  
  METHODS
  We used H(2)(15)O-positron emission tomography to analyze regional cerebral blood flow just before penile erection in heterosexual volunteers. The subjects viewed 3 different types of audiovisual materials-sexually explicit clips, nonsexual neutral clips and dynamic mosaic image control clips-presented in random order, and penile rigidity was monitored in real time with a RigiScan(R) Plus device. Positron emission tomography scanning was initiated simultaneously when each clip was started, and images obtained when the subjects showed appropriate penile response were analyzed and compared.
  
  
  RESULTS
  The advanced audiovisual cortices and cerebellar vermis in the right hemisphere were activated for sexually explicit-dynamic mosaic image control clip contrast, and only the right middle frontal gyrus was activated for sexually explicit- nonsexual neutral clip contrast. Several primary visual and audio regions were activated for dynamic mosaic image control-sexually explicit clip contrast and nonsexual neutral-sexually explicit clip contrast.
  
  
  CONCLUSIONS
  We speculate that advanced audiovisual activity with imagination, not primary visual and audio activity, occurs when men experience sexual arousal inducing penile erection. Furthermore, the cerebellar vermis may be a key region for induction of penile erection in humans.
authors.affiliation: Department of Urology, Osaka University Graduate School of Medicine, Osaka University, Suita, Japan. akitsuji@uro.med.osaka-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Tsujimura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyagawa
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Fujita
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: Tohru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takao
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Matsumiya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Osaki
authors.forename: Masashi
authors.initials: M
authors.lastname: Takasawa
authors.forename: Naohiko
authors.initials: N
authors.lastname: Oku
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kaneko
authors.forename: Akihiko
authors.initials: A
authors.lastname: Okuyama
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D002560:Cerebrovascular Circulation; D006801:Humans; D008297:Male; D010410:Penile Erection / Q000502:physiology*; D010775:Photic Stimulation; D049268:Positron-Emission Tomography