title: Central Somatosensory Networks Respond to a De Novo Innervated Penis: A Proof of Concept in Three Spina Bifida Patients.
abstract: BACKGROUND
  Spina bifida (SB) causes low spinal lesions, and patients often have absent genital sensation and a highly impaired sex life. TOMAX (TO MAX-imize sensation, sexuality and quality of life) is a surgical procedure whereby the penis is newly innervated using a sensory nerve originally targeting the inguinal area. Most TOMAX-treated SB patients initially experience penile stimulation as inguinal sensation, but eventually, the perception shifts to penis sensation with erotic feelings. The brain mechanisms mediating this perceptual shift, which are completely unknown, could hold relevance for understanding the brain's role in sexual development.
  
  
  OBJECTIVE
  The aim of this study was to study how a newly perceived penis would be mapped onto the brain after a lifelong disconnection.
  
  
  METHODS
  Three TOMAX-treated SB patients participated in a functional magnetic resonance imagery experiment while glans penis, inguinal area, and index finger were stimulated with a paint brush.
  
  
  METHODS
  Brush stimulation-induced activation of the primary somatosensory cortex (SI) and functional connectivity between SI and remote cerebral regions.
  
  
  RESULTS
  Stimulation of the re-innervated side of the glans penis and the intact contralateral inguinal area activated a very similar location on SI. Yet, connectivity analysis identified distinct SI functional networks. In all three subjects, the middle cingulate cortex (MCC) and the parietal operculum-insular cortex (OIC) were functionally connected to SI activity during glans penis stimulation, but not to SI activity induced by inguinal stimulation.
  
  
  CONCLUSIONS
  Investigating central somatosensory network activity to a de novo innervated penis in SB patients is feasible and informative. The consistent involvement of MCC and OIC above and beyond the brain network expected on the basis of inguinal stimulation suggests that these areas mediate the novel penis sensation in these patients. The potential role of MCC and OIC in this process is discussed, along with recommendations for further research.
authors: Department of Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors: Rudie
authors: R
authors: Kortekaas
authors: Department of Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors: Luca
authors: L
authors: Nanetti
authors: Department of Plastic, Reconstructive and Hand Surgery, Isala Klinieken, Zwolle, The Netherlands.
authors: Max L E
authors: ML
authors: Overgoor
authors: Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors: Bauke M
authors: BM
authors: de Jong
authors: Department of Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors: Janniko R
authors: JR
authors: Georgiadis
mesh_terms: D000328:Adult; D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010413:Penis / Q000294:innervation* / Q000601:surgery*; D011788:Quality of Life; D020127:Recovery of Function; D012684:Sensory Thresholds; D016135:Spinal Dysraphism / Q000503:physiopathology* / Q000523:psychology / Q000601:surgery; D014110:Touch; D013521:Urologic Surgical Procedures, Male
keywords: Body Image; Functional Connectivity; Penis; Peripheral Innervation; Primary Somatosensory Cortex; Spina Bifida; Surgery; fMRI