Functional Activity Mapping of the Perirolandic Cortex During Motor Performance and Motor Imagery

Abstract

The development of noninvasive magnetic resonance imaging (MRI) techniques sensitive to the local changes of blood flow, volume, and oxygenation which accompany neuronal activation has provided the scientific community with a new and powerful tool for investigating the spatio-temporal dynamics of human brain function [1,2]. One of the most exciting application of brain mapping techniques, such as single photon emission tomography (SPET), positron emission tomography (PET), and functional MRI (fMRI) is the study of neural correlates of mental activity, such as the internal representation of sensory events or motor acts. It is still debated to what extent brain networks activated during mental rehearsal of, for instance, a visual scene or a motor sequence (visual or motor imagery) overlap those involved in the perception of visual stimuli or the preparation and execution of motor acts, respectively [3]. With regard to the motor system, the results of previous SPET and PET studies have demonstrated the activation of higher-order motor areas (such as the supplementary motor cortex) during motor imagery, whereas no change was found in the primary sensory-motor cortex [4]. However, the relatively poor spatial resolution of the employed techniques may have prevented the detection of areas characterized by less intense activation. The present study was therefore undertaken to evaluate by high-resolution fMRI the activity pattern of the perirolandic region (including pre- and postcentral gyri) during execution and imagery of a sequential motor task.