Visuomotor mental rotation: the reaction time advantage for anti-pointing is not influenced by perceptual experience with the cardinal axes

In the visuomotor mental rotation (VMR) paradigm, participants execute a center-out reaching movement to a location that deviates from a visual cue by a predetermined instruction angle. Previous work has demonstrated a linear increase in reaction time (RT) as a function of the amplitude of the instruction angle (Georgopoulos and Massey in Exp Brain Res 65:361-370, 1987). In contrast, we recently reported a RT advantage for an instruction angle of 180A degrees relative to a 90A degrees angle (Neely and Heath in Neurosci Lett 463:194-198, 2009). It is possible, however, that perceptual expertise with the cardinal axes, which are perceptually familiar reference frames, influenced the results of our previous investigation. To address this issue, we employed a VMR paradigm identical to that of our previous work, with the exception that the stimulus array was shifted 45A degrees from the horizontal and vertical meridians. Our results demonstrated that RTs were fastest and least variable when the instruction angle was 0A degrees, followed by 180A degrees, which in turn, was faster than 90A degrees. Such findings establish that the RT advantage for the 180A degrees instruction angle is not influenced by perceptual expertise with the cardinal axes. Moreover, the present results provide convergent evidence that RT is not determined by the angle of rotation; instead, they indicate that response latencies reflect computational differences in the complexity of response remapping.