Time-Frequency Analysis of Increases in Vaginal Blood Perfusion Elicited by Long-Duration Pudendal Neuromodulation in Anesthetized Rats. 
Female sexual dysfunction (FSD) affects a significant portion of the population.  Although treatment options for FSD are limited, neuromodulation for bladder dysfunction has improved sexual function in some women.  A few studies have investigated peripheral neuromodulation for eliciting changes in vaginal blood flow, as a proxy for modulating genital sexual arousal, however results are generally transient.  Our central hypothesis is that repeated or extended-duration pudendal nerve stimulation can elicit maintained vaginal blood flow increases.  Under ketamine anesthesia, the pudendal nerve of 14 female rats was stimulated at varying frequencies (1-100 Hz) and durations (0.15-60 min).  Vaginal blood perfusion was measured with a laser Doppler flowmetry probe.  Changes in blood perfusion were determined through raw signal analysis and increases in the energy of neurogenic (0.076-0.200 Hz) and myogenic (0.200-0.740 Hz) frequency bands through wavelet analysis.  Additionally, a convolution model was developed for a carry-over stimulation effect.  Each experiment had significant increases in vaginal blood perfusion due to pudendal nerve stimulation.  In addition, there were large concurrent increases in neurogenic and myogenic frequency-band energy in 11/14 experiments, with an average maximal response at 31.3 min after stimulation initiation.  An effective stimulation model with a 30-min carry-over effect had a stronger correlation to blood perfusion than the stimulation period itself.  Repeated or extended-duration pudendal nerve stimulation can elicit maintained increases in vaginal blood perfusion.  This work indicates the potential for pudendal neuromodulation as a method for increasing genital arousal as a potential treatment for FSD.