Premium
Initiation and Suppression of Saccades by the Frontal Eye Field in the Monkey
Author(s) -
IZAWA YOSHIKO,
SUZUKI HISAO,
SHINODA YOSHIKAZU
Publication year - 2005
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1325.021
Subject(s) - paramedian pontine reticular formation , superior colliculus , supplementary eye field , neuroscience , stimulation , saccadic masking , eye movement , fixation (population genetics) , saccade , visual field , stimulus (psychology) , psychology , efferent , visual system , frontal eye fields , reticular formation , chemistry , visual cortex , afferent , cognitive psychology , biochemistry , gene
A bstract : After a saccadic eye movement occurs to an interesting object appearing in the visual field, visual fixation holds its image on the fovea and suppresses saccades to other objects appearing in the visual field. To understand the neural mechanism of visual fixation, the effects of electrical stimulation of the frontal eye field (FEF) on the generation of electrically evoked saccades (Esacs) and the suppression of saccades in trained monkeys were investigated. When the properties of the electrically evoked suppression of visually guided (Vsacs) and memory‐guided saccades (Msacs) were examined, two types of suppression were found. Stimulation of a wide area of the FEF suppressed only ipsiversive Vsacs and Msacs at stimulus intensities lower than those for eliciting Esacs, whereas stimulation of a localized area of the FEF suppressed the initiation of both Vsacs and Msacs in any direction during and ∼50 ms after stimulation. However, neither stimulation affected the vector of these saccades. The thresholds for suppression were usually less than 50 μA. The most effective stimulation timing for the suppression of ipsiversive and contraversive Vsacs was ∼40 to 50 ms before saccade onset. Therefore, suppression occurred in the efferent pathway for Vsacs at the premotor rather than the motoneuronal level, most likely in the superior colliculus and/or the paramedian pontine reticular formation. The results suggest that the suppression in the FEF may play a role in maintaining visual fixation by suppressing the generation of saccades.