Multiple frames of reference for pointing to a remembered target

Exp Brain Res (2005) 164: 301310

DOI 10.1007/s00221-005-2249-2RESEARCH ARTICLEMartin Lemay George E. StelmachMultiple frames of reference for pointing to a remembered targetReceived: 8 June 2004 / Accepted: 30 November 2004 / Published online: 22 March 2005

Springer-Verlag 2005Abstract Pointing with an unseen hand to a visual target

that disappears prior to movement requires maintaining

a memory representation about the target location. The

target location can be transformed either into a handcentered frame of reference during target presentation

and remembered under that form, or remembered in

terms of retinal and extra-retinal cues and transformed

into a body-centered frame of reference before movement initiation. The main goal of the present study was

to investigate whether the target is stored in memory in

an eye-centered frame, a hand-centered frame or in both

frames of reference concomitantly. The task was to locate, memorize, and point to a target in a dark environment. Hand movement was not visible. During the

recall delay, participants were asked to move their hand

or their eyes in order to disrupt the memory representation of the target. Movement of the eyes during the

recall delay was expected to disrupt an eye-centered

memory representation whereas movement of the hand

was expected to disrupt a hand-centered memory representation by increasing movement variability to the

target. Variability of movement amplitude and direction

was examined. Results showed that participants were

more variable on the directional component of the

movement when required to move their hand during

recall delay. On the contrary, moving the eyes caused an

increase in variability only in the amplitude component

of the pointing movement. Taken together, these results

suggest that the direction of the movement is coded and

remembered in a frame of reference linked to the arm,

whereas the amplitude of the movement is remembered

in an eye-centered frame of reference.Keywords Target Pointing Memory Eye HandIntroductionPointing movements are most accurate when both the

hand and the target are visible. In that situation, retinal

and extra-retinal cues combine to form a viewer-centered representation. This representation allows one to

plan and execute the movement accurately, with no need

to account for the proprioceptive signal from the hand

(Berbinklit et al. 1995). When the hand is visible but the

target is not visible, the remembered target is...