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Distinct control of initiation and metrics of memory-guided saccades and vergence by the FEF: a TMS study.

Yang Q, Kapoula Z - PLoS ONE (2011)

Bottom Line: This study is to explore the effect of transcranial magnetic simulation (TMS) over FEF on the control of memory-guided saccade-vergence eye movements.TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF.The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

View Article: PubMed Central - PubMed

Affiliation: IRIS Group, UMR 8194, CNRS, Hôpital Européen Georges Pompidou, Paris, France. qing.yang@egp.aphp.fr

ABSTRACT

Background: The initiation of memory guided saccades is known to be controlled by the frontal eye field (FEF). Recent physiological studies showed the existence of an area close to FEF that controls also vergence initiation and execution. This study is to explore the effect of transcranial magnetic simulation (TMS) over FEF on the control of memory-guided saccade-vergence eye movements.

Methodology/principal findings: Subjects had to make an eye movement in dark towards a target flashed 1 sec earlier (memory delay); the location of the target relative to fixation point was such as to require either a vergence along the median plane, or a saccade, or a saccade with vergence; trials were interleaved. Single pulse TMS was applied on the left or right FEF; it was delivered at 100 ms after the end of memory delay, i.e. extinction of fixation LED that was the "go" signal. Twelve healthy subjects participated in the study. TMS of left or right FEF prolonged the latency of all types of eye movements; the increase varied from 21 to 56 ms and was particularly strong for the divergence movements. This indicates that FEF is involved in the initiation of all types of memory guided movement in the 3D space. TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF.

Conclusions/significance: The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

Show MeSH
Mean values of percentage error amplitude (PEA) with standard error.(A) for saccades to left, saccades to right, divergence and convergence, (B) for combined convergent movements and (C) for combined divergent movements under the three experimental conditions: no-TMS, TMS over the right, or the left FEF. Asterisks indicate significant increases of PEA after TMS over the left or the right FEF relative to no-TMS.
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pone-0020322-g003: Mean values of percentage error amplitude (PEA) with standard error.(A) for saccades to left, saccades to right, divergence and convergence, (B) for combined convergent movements and (C) for combined divergent movements under the three experimental conditions: no-TMS, TMS over the right, or the left FEF. Asterisks indicate significant increases of PEA after TMS over the left or the right FEF relative to no-TMS.

Mentions: Figure 3 presents the group mean PEA for saccades to left or to right, for divergence and convergence (A), for components of combined convergent movements (B) and for components of combined divergent movements (C) under three conditions: no-TMS, TMS over the right or the left FEF. The Friedman test applied on the PEA under no-TMS condition showed significant effect of type of eye movement (Chi22,12 = 37.2, p<0.001). For pure eye movements, vergence (both divergence and convergence) showed higher PEA than pure saccades (both leftward and rightward, all p<0.05, Wilcoxon test). For combined eye movements, only leftward saccade components of combined convergent movements and convergent components of combined leftward movements showed higher PEA than their corresponding pure eye movements (both p<0.05).


Distinct control of initiation and metrics of memory-guided saccades and vergence by the FEF: a TMS study.

Yang Q, Kapoula Z - PLoS ONE (2011)

Mean values of percentage error amplitude (PEA) with standard error.(A) for saccades to left, saccades to right, divergence and convergence, (B) for combined convergent movements and (C) for combined divergent movements under the three experimental conditions: no-TMS, TMS over the right, or the left FEF. Asterisks indicate significant increases of PEA after TMS over the left or the right FEF relative to no-TMS.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102701&req=5

pone-0020322-g003: Mean values of percentage error amplitude (PEA) with standard error.(A) for saccades to left, saccades to right, divergence and convergence, (B) for combined convergent movements and (C) for combined divergent movements under the three experimental conditions: no-TMS, TMS over the right, or the left FEF. Asterisks indicate significant increases of PEA after TMS over the left or the right FEF relative to no-TMS.
Mentions: Figure 3 presents the group mean PEA for saccades to left or to right, for divergence and convergence (A), for components of combined convergent movements (B) and for components of combined divergent movements (C) under three conditions: no-TMS, TMS over the right or the left FEF. The Friedman test applied on the PEA under no-TMS condition showed significant effect of type of eye movement (Chi22,12 = 37.2, p<0.001). For pure eye movements, vergence (both divergence and convergence) showed higher PEA than pure saccades (both leftward and rightward, all p<0.05, Wilcoxon test). For combined eye movements, only leftward saccade components of combined convergent movements and convergent components of combined leftward movements showed higher PEA than their corresponding pure eye movements (both p<0.05).

Bottom Line: This study is to explore the effect of transcranial magnetic simulation (TMS) over FEF on the control of memory-guided saccade-vergence eye movements.TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF.The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

View Article: PubMed Central - PubMed

Affiliation: IRIS Group, UMR 8194, CNRS, Hôpital Européen Georges Pompidou, Paris, France. qing.yang@egp.aphp.fr

ABSTRACT

Background: The initiation of memory guided saccades is known to be controlled by the frontal eye field (FEF). Recent physiological studies showed the existence of an area close to FEF that controls also vergence initiation and execution. This study is to explore the effect of transcranial magnetic simulation (TMS) over FEF on the control of memory-guided saccade-vergence eye movements.

Methodology/principal findings: Subjects had to make an eye movement in dark towards a target flashed 1 sec earlier (memory delay); the location of the target relative to fixation point was such as to require either a vergence along the median plane, or a saccade, or a saccade with vergence; trials were interleaved. Single pulse TMS was applied on the left or right FEF; it was delivered at 100 ms after the end of memory delay, i.e. extinction of fixation LED that was the "go" signal. Twelve healthy subjects participated in the study. TMS of left or right FEF prolonged the latency of all types of eye movements; the increase varied from 21 to 56 ms and was particularly strong for the divergence movements. This indicates that FEF is involved in the initiation of all types of memory guided movement in the 3D space. TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF.

Conclusions/significance: The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

Show MeSH