CHANGES IN REGIONAL CEREBRAL BLOOD-FLOW RELATED TO LINE BISECTION DISCRIMINATION AND VISUAL-ATTENTION USING HMPAO-SPECT

Behavioral tasks requiring visual-spatial discrimination such as line bisection are used clinically to assess right hemisphere function, yet the anatomical substrate of line bisection has yet to be elucidated b y functional imaging. In the current study, nine right-handed, healthy adult subjects underwent split-dose technetium-99m-hexamethylpropylen e amine oxime single photon emission tomography during performance of two visual tasks. Statistical parametric maps that represented signifi cant changes in regional cerebral blood flow (rCBF) for each task were generated. Increases in rCBF were seen in the right dorsolateral pref rontal cortex, the insula, and the superior temporal lobe with a line- bisection discrimination task, whereas increases in the visual associa tion areas, the posterior cingulate gyrus bilaterally, and the anterio r cingulate gyrus on the right were seen with a similar control task w hich required sustained visual attention, but no visual spatial discri mination. We conclude that distinct areas in the nondominant hemispher e can be shown to be active during performance of line-bisection discr imination and sustained visual attention. (C) 1997 Academic Press.