Regional brain activity during different paradigms of mental rotation in healthy volunteers: A positron emission tomography study

Positron emission tomography (PET) was used to observe changes in regional cerebral blood flow (rCBF) in 10 right-handed healthy volunteers performing two paradigms of mental rotation. In one paradigm, subjects mentally rotat ed a single alphanumeric stimulus to determine whether it was shown in a no rmal or mirror-image position. In a second paradigm, subjects mentally rota ted and compared pairs of figurative stimuli to determine whether the stimu li were identical or mirror-images. In both paradigms, rCBF was compared wi th a control task that used identical stimuli, but required no mental rotat ion. Mental rotation of single alphanumeric stimuli engendered activation i n the primary somatomotor area in the left precentral gyrus, Mental rotatio n of paired figures engendered activation in the left superior parietal lob ule and the right frontal medial gyrus, A deactivated area was located in t he medial part of the left superior frontal gyrus, Comparison of both parad igms revealed that the left gyrus precentralis was activated significantly during the alphanumeric condition and that the left gyrus lingualis was sig nificantly activated during the paired figures condition. Motor processes m ay be an inherent part of every mental rotation but the type of motor invol vement appears strongly dependent on the specific task or the specific stim uli. Similar paradigms, designed to isolate the same cognitive function, in the same subjects, using the same imaging technology and methodology, but differing only in stimulus material, lead to different areas of neural acti vation. Task specificity determines the most significant changes in cerebra l blood flow in different mental rotation paradigms. (C) 2001 Academic Pres s.