Auditory and tactile processing in a postmeningitic deaf-blind patient with a cochlear implant

Brain responses during the first desire to void: a positron emission tomography study

OBJECTIVES

First desire to void (FDV) is defined as the first feeling that would lead the patient to pass urine. The aim of the present study is to identify the brain regions activated during FDV.

METHODS

Six healthy right-handed male volunteers, aged 31-40 years, agreed to participate in this study. Rather than inserting a urethral catheter, we used a urinary volume monitoring unit and a self-adhesive external condom catheter for this study. Positron emission tomography (PET) scans obtained in the FDV and post-voiding (absence of urge to void) (REST) states were analyzed and compared.

RESULTS

First desire to void state was associated with increased blood flow in the right and left cerebellum, right parahippocampal gyrus (Brodmann area [BA] 30), left superior frontal gyrus (BA9), and left cingulate gyrus (BA32). Rest state was associated with decreased blood flow in the right superior temporal gyrus (BA22), right uncus (BA28), right cingulate gyrus (BA32), left middle temporal gyrus (BA21), and left medial frontal gyrus (BA25). According to region of interest analysis, regional cerebral blood flow of the periaqueductal grey and pons was significantly increased at FDV as opposed to REST.

CONCLUSIONS

We located possible brain activity associated with the FDV sensation. Combined activation of the right and left cerebellum, parahippocampal gyrus, superior frontal gyrus, and left cingulate gyrus could be associated with FDV.

Differential brain processing of audiovisual sexual stimuli in men: Comparative positron emission tomography study of the initiation and maintenance of penile erection during sexual arousal

The human male psychosexual cycle consists of four phases: excitation, plateau, orgasm, and resolution. Identification of the specific neural substrates of each phase may provide information regarding the brain's pathophysiology of sexual dysfunction. We previously analyzed regional cerebral blood flow (rCBF) with H(2)15O-positron emission tomography (PET) during the excitation phase (initiation of penile erection) induced by audiovisual sexual stimuli (AVSS) and identified activation of the cerebellar vermis, the bilateral extrastriate cortex, and right orbitofrontal cortex, suggesting a role of cognition/emotion in the excitement phase. In the present study, we analyzed rCBF of the same six healthy volunteers during the plateau phase (maintenance of penile erection) induced by AVSS and compared the results with those of the excitation phase. Penile rigidity was monitored in real time with RigiScan Plus during PET scanning. Images were analyzed by statistical parametric mapping (SPM) software, and rCBF in the amygdala, hypothalamus, anterior cingulate, and insula was measured. During the plateau phase, primary subcortical activation was noted in the right ventral putamen, indicating motivational factors in the sexual response via the limbic reward circuit. A significant increase in rCBF in the left hypothalamus was also observed during the plateau phase. The right anterior cingulate and left insula were specifically activated during the excitation phase but not during the plateau phase. These results indicate a significant role of the ventral putamen and the hypothalamus in the plateau phase and confirm that paralimbic and limbic components of the human brain differentially coordinate the sexual response in a psychosexual phase-dependent manner.