Page 73 - Bladder Dysfunction in the Context of the Bladder-Brain Connection - Ilse Groenendijk.pdf

Whole brain 7T-fMRI during pelvic floor muscle contraction in male subjects 71
The cingulate gyrus
The mid cingulate gyrus was activated bilaterally during PFMC and tongue movements. The location is comparable to previous studies during similar tasks: repetitive PFMC with empty bladder.4,5,23 The involvement of this cluster can be explained by the presumed role of the MCG in the decision to perform a reward based motor task.31
The insula
Bilateral anterior insular activity was found during both tasks. Insular activity during PFMC and tongue movement is described before, but not particularly in the anterior insula.4,20,23,32 The conducted connectivity analysis showed that the insula is connected to cortical structures like the SMA but also to the MCG. Evidence suggests that the an- terior insula is in particular strongly connected to the MCG to regulate attention related responses, for instance pelvic floor contractions for retaining continence.33 Additionally, the insula shows an increased connectivity to the motor cortex in patients with chronic pelvic pain syndrome compared to healthy controls, explained by the insular involve- ment of visceral sensations.10 In future this might be of great interest to further explore the pathophysiology of PDF’s.
Cerebellum
The cerebellum contains a double homunculus, one in the anterior lobe and a reversed in the posterior lobe.34 We investigated anterior cerebellum activation not only for groups but also for single subjects. We found clusters in lobules I-IV of the cerebellum during PFMC, and clusters in lobule VI during tongue movement. This ‘up-side-down’ somato- topic representation of the human body agrees with previously obtained somatotopic maps.35 This is the first study to show these results during PFMC in single subjects, which are comparable to two other studies on group analysis of cerebellar activations during PFMC.3,6 In single subjects, tongue movement created large and consistent clusters in the cerebellum compared to PFMC. The ratio of the size of these tongue and PFMC clus- ters appear comparable to the ratio of the found clusters on the primary motor cortex.
Tongue movements as control task
Tongue movements were chosen as a control task, since this midline motor task can be controlled both voluntarily and involuntarily, like PFMC. PFMC presumably diverges from tongue movement, because it may involve more affective-emotional aspects. Moreover, tongue movement is a more conditioned motor task, which explains the different con- nectivity during the two tasks. Existing literature describes active clusters during tongue movement in the same brain areas as the active clusters found in the present study with comparable coordinates,27,36 also for the cerebellar clusters.35
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