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Extraretinal modulation of accessory optic units in the pigeon
1Departamento de Fisiologia e Biofisica, Universidade de São Paulo, Brasil.
Summary
Pigeon brain regions, the pretectum and telencephalon, control the nucleus of the basal optic root (nBOR). Stimulation revealed directional preferences in nBOR units, impacting optokinetic nystagmus neural substrates.
Area of Science:
- Neuroscience
- Comparative Neuroanatomy
Background:
- The accessory optic system is crucial for gaze stabilization.
- The nucleus of the basal optic root (nBOR) plays a role in processing visual motion information.
Purpose of the Study:
- To investigate the pretectal and telencephalic control mechanisms of the nucleus of the basal optic root (nBOR) in pigeons.
- To elucidate the neural substrates underlying optokinetic nystagmus.
Main Methods:
- Electrophysiological recordings were performed on pigeon nBOR units.
- Electrical stimulation of the pretectal lentiform nucleus (LM) and visual Wulst (W) was employed.
Main Results:
- LM stimulation primarily excited temporal-to-nasal preferring nBOR units and inhibited nasal-to-temporal preferring units.
- Visual Wulst stimulation mainly inhibited downward-preferring nBOR units and showed mixed effects on upward-preferring units.
- Stimulation latencies differed between LM (mean 5.5 ms) and W (mean 13.0 ms).
Conclusions:
- The pretectum and telencephalon exert differential control over nBOR units based on directional preference.
- These findings contribute to understanding the neural circuitry of the optokinetic reflex.