Use of positron emission tomography and evoked potentials in the detection of cortical afferents from the gastrointestinal tract.

OBJECTIVE

Positron emission tomography permits precision identification of the cerebral regions involved in physiologic functions. As the cerebral localization for visceral sensation has not been identified, our aim was to examine the cerebral viscerotopic representation for rectal sensation.

METHODS

Cerebral-evoked potentials were measured in five healthy volunteers who underwent rectal balloon distension. Simultaneously, cerebral blood flow was measured using positron emission tomography with 15H2O.

RESULTS

A cerebral-evoked potential occurred with rectal balloon distension. An increase in cerebral blood flow was noted in the pre- and postcentral gyrus and the thalamus.

CONCLUSION

The techniques for measuring cerebral-evoked potentials and cortical blood flow are useful in the delineation of the cerebral regions subserving visceral sensation.