Antisaccade generation is impaired after parietal lobe lesions
James A Sharpe1, Ping Cheng, Moshe Eizenman
1Division of Neurology, University Health Network, Toronto, Ontario, Canada. james.sharpe@uhn.on.ca
Annals of the New York Academy of Sciences
|September 29, 2011
Summary
Parietal lobe lesions impair voluntary eye movements called antisaccades, which move away from visual stimuli. This suggests the parietal lobe is crucial for controlling these eye movements, not just the frontal lobe.
Area of Science:
- Neuroscience
- Ophthalmology
- Cognitive Science
Background:
- Antisaccade generation, voluntary eye movements away from visual targets, is typically linked to frontal lobe function.
- Parietal lobe involvement in antisaccade control has been less understood, particularly concerning focal lesions.
Purpose of the Study:
- To investigate the role of the parietal lobe in antisaccade generation.
- To assess the impact of unilateral focal parietal lobe lesions on antisaccade performance.
Main Methods:
- Studied antisaccade performance in 13 patients with unilateral focal parietal lobe lesions and 10 healthy controls.
- Participants performed 10° antisaccades in response to a central target flash.
- Lesion locations were imaged in nine patients, focusing on white matter involvement.
Main Results:
- Patients with parietal lesions exhibited significantly impaired antisaccade generation (55.4% contraversive, 50.5% ipsiversive) compared to controls (86.1%).
- Reflexive saccades toward the target occurred frequently in patients.
- Nine patients with overlapping parietal white matter lesions showed consistently subnormal antisaccade performance.
Conclusions:
- Parietal lobe lesions disrupt voluntary saccade control, specifically antisaccade generation.
- Impaired antisaccade performance in these patients is likely due to a disconnection between parietal and frontal lobe ocular motor areas.
- Antisaccades serve as a valuable tool for assessing parietal lobe voluntary saccade function, independent of visual guidance.
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