Ej. Tehovnik et al., SACCADES INDUCED ELECTRICALLY FROM THE DORSOMEDIAL FRONTAL-CORTEX - EVIDENCE FOR A HEAD-CENTERED REPRESENTATION, Brain research, 795(1-2), 1998, pp. 287-291
The amplitude and direction of saccadic eye movements evoked electrica
lly from the dorsomedial frontal cortex (DMFC) of monkeys vary with st
arting eye position. This observation has been used to argue that the
DMFC codes saccadic eye movements in head-centered coordinates. Whethe
r the amplitude and direction of the evoked saccades are also affected
by changes in head position has never been demonstrated. Such a resul
t would argue against a head-centered representation, and instead woul
d suggest a representation anchored to another body part. Tests were c
onducted on rhesus monkeys to determine whether changing the position
of the head with respect to the trunk or changing the position of the
head with respect to the gravitational axis alters saccadic parameters
. The amplitude and direction of saccadic eye movements remained invar
iant to such manipulations. These findings confirm the claim that the
DMFC encodes saccadic eye movements in head-centered coordinates. (C)
1998 Elsevier Science B.V. All rights reserved.