Psychophysiological correlates of dynamic imagery

Brain Electrical Activity Maps were recorded from 20 subjects whilst performing: (a) the Vandenberg & Kuse Mental Rotation Test (MRT) and: (b) the Isaac, Marks & Russell Vividness of Movement Imagery Questionnaire (VMIQ), and under control conditions. Subjects were classified as good or poor imagers, first on the basis of their VMIQ scores, and secondly on their MRT scores. Alpha, beta 1 and beta 2 at different cortical regions were compared between groups and between task performance and control conditions. During MRT significant reductions in alpha amplitude were found over both right and left parietal areas and over the left frontal region. In beta 1 non-significant trends in the same direction were observed in the same regions found to be significant in alpha. Non-significant trends in beta 2 were observed over the right parietal and frontal regions. No differences in amplitude at any frequency band were found between good and poor VMIQ scorers but subjects with high MRT scores showed greater alpha amplitude at many sites in the parietal, parieto-occipital and frontal areas than subjects with low MRT scores. During VMIQ testing the VMIQ high imagers showed a non-significant trend towards higher alpha amplitude at frontal regions and some scattered parietal and occipital sites and significantly higher levels of beta 2 in the left frontal region. However, no differences were found between imagery and control conditions. The results confirm the involvement of motor as well as spatial processes in dynamic imagery.