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A true neuronal consensual pupillary reflex in chicks.
1Section of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA. TL24@Cornell.edu
Vision Research
|May 26, 1999
Summary
This study confirms a neuronal consensual pupillary reflex (CPR) in chickens. Optic nerve transection in chicks revealed indirect pupillary responses, proving the existence of a neuronal CPR in avian species.
Area of Science:
- Neuroscience
- Avian Biology
- Ophthalmology
Background:
- The existence of a neuronal consensual pupillary reflex (CPR) in birds remains a subject of debate.
- Previous studies offered conflicting evidence, with claims of CPR contradicted by observations of light transmission effects.
Purpose of the Study:
- To definitively determine if a neuronal CPR exists in chickens.
- To resolve the historical debate regarding avian pupillary reflexes.
Main Methods:
- Optic nerves of 28 chicks were surgically transected.
- Direct and indirect pupillary responses were observed and videotaped in both operated and non-operated eyes.
Main Results:
- Twenty-one chicks showed no direct pupillary response in the operated eye but exhibited an indirect response.
- The non-operated eye displayed a direct response but no indirect response.
Conclusions:
- These findings provide conclusive evidence for the presence of a true neuronal consensual pupillary reflex (CPR) in chickens.
- The study resolves the long-standing debate on avian CPR, establishing its neuronal basis.