Neurosci Lett. 2011 May 16;495(2):102-6 doi: 10.1016/j.neulet.2011.03.048. 2011 Mar 31.

Neuropsychological evidence for three distinct motion mechanisms

Vaina LM, Dumoulin SO.

Abstract

We describe psychophysical performance of two stroke patients with lesions in distinct cortical regions in the left hemisphere. Both patients were selectively impaired on direction discrimination in several local and global second-order but not first-order motion tasks. However, only patient FD was impaired on a specific bi-stable motion task where the direction of motion is biased by object similarity. We suggest that this bi-stable motion task may be mediated by a high-level attention or position based mechanism indicating a separate neurological substrate for a high-level attention or position-based mechanism. Therefore, these results provide evidence for the existence of at least three motion mechanisms in the human visual system: a low-level first- and second-order motion mechanism and a high-level attention or position-based mechanism.

PMID: 21440602