
Erection response to sexual interest is the result of interplay between tactile, visual, auditory, and olfactory signals, combined with cognitive inputs, such as fantasy and memory (Figure 1). These stimuli may be erectogenic or erectolytic, pleasant or unpleasant, and are integrated in specific nuclei within the mid-brain. This balance between stimuli may result in pro-erectile signaling transmitted via the spinal cord, pelvic nerves and cavernous nerves running either side of the prostate gland, before finally terminating around the vascular smooth muscle of the corpora cavernosa.