PARAMETRIC ANALYSIS OF FUNCTIONAL NEUROIMAGES - APPLICATION TO A VARIABLE-RATE MOTOR TASK

Positron emission tomography (PET) has proven to be a powerful tool in identifying the functional neuroanatomy underlying cognitive and sens orimotor processing. In this paper, we present a method for mathematic ally modeling the changes in regional cerebral blood flow (rCBF) as a function of experimental parameters using step and linear functions. P ET was used to measure rCBF in six subjects who tracked a target movin g with constant amplitude across a computer screen at four different f requencies. Each subject tracked the target by flexing and extending t he wrist. Two scans were performed at each frequency. The data for eac h subject were normalized by the mean blood how in each scan and scale d to the mean blood how at rest. Scaled rCBF was regressed onto moveme nt frequency to identify voxels which had either a significant linear or step function response to the frequency of movement. A group analys is was also performed to identify significant functional changes commo n to all subjects. Significant rCBF increases in relation to movement frequency were found in the supplementary motor area, primary motor co rtex, premotor cortex, thalamus, and cerebellum and localized using th e Talairach atlas. Habituation of responses was not observed. (C) 1995 Academic Press, Inc.