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Behavioral Assessment of Manual Dexterity in Non-Human Primates
Published on: November 11, 2011
Downward gaze in monkeys: stimulation and lesion studies
Brain : a Journal of Neurology
|September 1, 1979
Summary
Bilateral stimulation of specific brain regions in monkeys caused downward eye movements. Lesions in these prerubral fields resulted in gaze defects, indicating their critical role in downward eye control.
Area of Science:
- Neuroscience
- Ophthalmology
- Neuroanatomy
Background:
- Vertical eye movements are complex and involve multiple brainstem structures.
- The precise neural circuits controlling downward gaze, particularly rapid eye movements, remain incompletely understood.
Purpose of the Study:
- To investigate the neural structures responsible for generating downward vertical eye movements.
- To determine the effects of lesions in specific brain regions on downward gaze control.
Main Methods:
- Stereotactic stimulation and electrolytic lesions were performed in ten monkeys.
- Eye movements were monitored during stimulation and following lesions.
- Responses to various oculomotor tests, including optokinetic and vestibulo-ocular reflexes, were assessed.
Main Results:
- Bilateral stimulation of the prerubral fields elicited downward eye movements.
- Bilateral lesions in this region caused significant defects in downward saccadic and pursuit eye movements.
- Optokinetic and vestibulo-ocular reflexes showed abnormalities in vertical gaze, with preserved horizontal movements.
- Recovery was incomplete for rapid downward eye movements.
Conclusions:
- The prerubral fields contain critical structures for downward gaze, especially rapid eye movements.
- Bilateral lesions in this area lead to isolated downward gaze palsy.
- These findings in monkeys are likely applicable to humans, confirming bilateral innervation for downward eye movements.
