SPECT (HMPAO) SUPPORT FOR ACTIVATION OF THE MEDIAL PREFRONTAL CORTICES DURING TOE GRAPHAESTHESIA

This experiment was designed to test the construct validity of psychom etric analyses that suggested a strong functional association between the accuracy for toe graphaesthesia and selective activation of neuron s within the medial prefrontal regions. Single Photon Emission Compute rized Tomography (SPECT) profiles were obtained for three volunteers ( 2 men, 1 woman) after they had been exposed to a toe graphaesthesia ta sk or had been exposed to the control setting. The two measurements fo r each participant were separated by at least one week. Qualitative ev aluation, using criteria employed for clinical diagnoses, of serial co ronal, sagittal, and horizontal sections clearly indicated a specific increase in uptake of tracer within the rostral one-third to one-half of the medial prefrontal cortices of all three subjects during the toe graphaesthesia task compared to that during baseline conditions. The results are consistent with our neuropsychological research which indi cates that toe graphaesthesia may be an accurate and useful indicator of the functional integrity of the medial surfaces of the anterior cer ebral hemispheres.