Influence of the referential framework in the human pursuit coding system

A smooth pursuit eye movement (SPEM) deficit differs according to the location of the focal lesion.1 Occipitoparietal lesions induce craniotopic deficits, with slower SPEM velocity in the contralateral hemifield. A lesion to the frontal eye field (FEF) induces an ipsiversive defect, with decreased SPEM velocity when the eye is moved toward the side of the lesion, regardless of the hemifield. Direct human intracerebral EEG (iEEG) of 2 patients with epilepsy during pursuit revealed a specific increase in broadband gamma high-frequency activity (HFA) (50–150 Hz) in the cuneus and FEF.2 By analyzing the neural activity according to pursuit direction, we highlight how cortical SPEM areas use different referential frameworks to code eye movement.