Improved steering performance with enhanced recruitment of the superior parietal lobe: An fMRI study

Abstract

Navigating successfully through the environment typically involves both detection of current egomotion as well as anticipation of impending changes in heading trajectory. Here we build upon our previous finding of increased activation in a region of the superior parietal lobe (SPL) and the medial intraparietal sulcus when future path information allowed for greater anticipation of heading response. In the present study we use a slalom steering paradigm, which required participants to navigate around objects in a virtual world using a joystick in the fMRI scanner. Future obstacles were either all revealed to the participant at the start of the trial in steering preview trials (allowing for future planning), or revealed one by one with an impending obstacle being revealed when the current obstacle was being passed in steering near trials (initiate steering only ∼2 sec before the object would be reached). These active steering trials were matched in terms of motor requirements and visual properties using passive heading (preview and near) trials in which participants were replayed their previous steering trials and merely had to mimic their virtual heading. Results confirmed SPL recruitment during steering trials, with a more extensive network during steering preview compared to steer near trials. Correlational analysis of fMRI data with respect to individual behavioural performance revealed that there was increased activation of an anterior (and partially overlapping) region of the SPL in participants who exhibited smoother steering performance. These findings are interpreted in terms of a role for the SPL in spatial encoding and updating of future targets or obstacles during forward locomotion, and a potential neural underpinning for improved steering performance on an individual basis.

EPSRC.