Widespread dorsal stream activation during a parametric mental rotation task, revealed with functional magnetic resonance imaging.

Following a parametrically modulated mental rotation task, in which 10 healthy subjects were instructed to determine whether alphanumeric characters were normal or mirror-reversed, bilateral dorsal stream activations culminating in the intraparietal region were revealed with functional magnetic resonance imaging. Although the parietal activations were bilateral, we observed a right hemispheric dominance for the task, consistent with our previous findings (I. M. Harris et al., 2000). By studying individual activation maps in response to the paradigm, we discerned parcellation of the intraparietal region into discrete subdivisions. In this paper, we address the involvement of structures surrounding the intraparietal sulcus in mental rotation, as well as describing a wider visuospatial attentional network, encompassing neural substrates within the dorsal stream.