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Pursuit deficits in bilateral pulvinar lesions
K Ohtsuka1, Y Igarashi, H Maekawa
1Department of Ophthalmology, Sapporo Medical College, Japan.
Summary
Bilateral pulvinar infarctions caused smooth pursuit deficits in a patient. This suggests efferent fibers from the cortical pursuit center travel through the pulvinar in humans, similar to monkeys.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Smooth pursuit eye movements are crucial for visual tracking.
- The pulvinar nucleus's role in visual processing and eye movements is under investigation.
- Previous studies in monkeys suggested pulvinar involvement in efferent visual pathways.
Purpose of the Study:
- To investigate the role of the pulvinar in human smooth pursuit eye movements.
- To determine if pulvinar lesions impact specific eye movement control pathways.
Main Methods:
- Case study of a 58-year-old male patient with bilateral pulvinar infarctions.
- Assessment of horizontal and vertical smooth pursuit eye movements.
- Evaluation of saccadic eye movement metrics.
- Measurement of optokinetic nystagmus gain.
Main Results:
- The patient exhibited deficits in both horizontal and vertical smooth pursuit.
- Saccadic eye movement metrics remained within normal limits.
- Optokinetic nystagmus gain was slightly reduced.
Conclusions:
- These findings support the hypothesis that efferent fibers from the cortical pursuit center traverse the pulvinar in humans.
- The pulvinar appears critical for the normal execution of smooth pursuit eye movements.
- This case provides human evidence consistent with prior monkey studies on pulvinar function in eye movement control.