The effects of voluntary lateral orienting on positive manifold for lateralized cognitive tasks.

As an extension of previous studies (Urbanczyk, Angel, & Kennelly, Brain and Cognition, 8, 206-226) examining the effects of unimanual tapping on lateralized cognitive tasks, lateral body orienting was added to an established dual task paradigm to generate differential hemispheric activation and shifts of attention. One hundred twenty right-handed university students retained sequences of digits or spatial locations for 20 sec either alone or during finger tapping. By turning head and eyes left or right, the hemisphere congruent with the sequences (LH for digits, RH for locations) or incongruent (vice versa) was activated. Activation had little effect on retention means but greatly affected resource composition, supporting task performance. Congruent orientation produced significantly higher positive correlations between digit and location tasks than incongruent orientation. Females showed higher sequence retention correlations than males across both orienting groups. For females, congruent activation enhanced tapping rates and tapping-retention task correlations. For males, activation affected neither of these. These results suggest that congruent attentional orienting may couple or integrate regions of the less activated hemisphere into networks of the more activated hemisphere. Greater inter- and intrahemispheric connectivity in the female cortex may produce a greater dependence upon a general attentional "resource."