Imaging functional activation of the auditory cortex during focal repetitive transcranial magnetic stimulation of the primary motor cortex in normal subjects

Positron emission tomography (PET) during focal repetitive transcranial mag netic stimulation (rTMS) has emerged as a promising approach to study corti cal connectivity in awake humans. However, the noise caused by the discharg ing magnetic coil might have confounding effects on the rTMS-related cortic al activation pattern. In twelve healthy volunteers, 1 8-fluoro-2-deoxy-D-g lucose ((18)FDG) PET was employed to visualize the functional activation of the primary auditory cortex (PAC) during 2 Hz rTMS of the left primary sen sorimotor hand area. Magnetic stimuli (1800) were applied at an intensity o f 140% of motor resting threshold during the uptake period of (18)FDG. Thou gh all subjects wore earplugs, rTMS-related noise induced a consistent bila teral increase of regional glucose utilization in the PAC(P < 0.05, correct ed). Thus, rTMS-related acoustic input needs to be taken into account in co mbined rTMS/PET studies. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.