The frontal eye field is involved in spatial short-term memory but not in reflexive saccade inhibition

Abstract

Physiological studies in monkeys have shown that the frontal eye field (FEF) is involved in the preparation and triggering of purposive saccades. However, several questions of FEF function remain unclear: the role of the FEF in visual short-term memory, its ability to update its spatial map and its role in reflexive saccade inhibition. We have addressed these issues in a patient with a small acute ischemic lesion whose location corresponded very accurately to the region of the left FEF according to the most recent cerebral blood flow studies. An initial study was conducted on days 7 and 8 after the stroke, i.e., before substantial recovery. A first group of paradigms (smooth pursuit, simple saccade tasks) was performed to assess FEF dysfunction. In a second group of paradigms, (1) visual short-term memory was tested by means of memory-guided saccade paradigms with short and long delays (1 and 7 s), (2) spatial updating abilities were tested by a double-step saccade task and two memory-guided saccade tasks in which the central fixation point was displaced during the memorization delay, and (3) reflexive saccade inhibition was tested by the antisaccade task. Results show that the FEF is involved in short-term memorization of the parameters of the forthcoming memory-guided saccade encoded in oculocentric coordinates. Normal results in the antisaccade task suggest that the FEF is not involved in reflexive saccade inhibition.