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Spectral mechanisms in the tree squirrel retina
B Blakeslee1, G H Jacobs, J Neitz
1Department of Psychology, University of California, Santa Barbara 93106.
Journal of Comparative Physiology. A, Sensory, Neural, and Behavioral Physiology
|April 1, 1988
Summary
Gray squirrels possess dichromatic color vision, with their retina utilizing three spectral mechanisms for vision. This research details the spectral sensitivities of their rods and cones.
Area of Science:
- Vision science
- Neuroethology
- Comparative physiology
Background:
- The retina of the gray squirrel (Sciurus carolinensis) has a rod to cone ratio of approximately 2:3.
- Understanding the spectral mechanisms of vision is crucial for comprehending animal color perception.
Purpose of the Study:
- To investigate the spectral mechanisms underlying vision in the gray squirrel retina.
- To determine the number and spectral sensitivities of the visual mechanisms in this species.
Main Methods:
- Behavioral experiments were conducted to test color vision.
- Electrophysiological recordings were made from single optic nerve fibers.
- Flicker photometric electroretinogram (ERG) analysis was performed.
Main Results:
- Gray squirrels exhibit dichromatic color vision with a spectral neutral point around 500 nm.
- Three distinct spectral mechanisms were identified in the gray squirrel retina.
- A rod-based mechanism peaks at approximately 502 nm.
- Two cone-based mechanisms show peak sensitivities around 444 nm and 543 nm.
Conclusions:
- The gray squirrel's visual system is based on three spectral mechanisms, including one rod and two cone types.
- The identified spectral sensitivities align with dichromatic color vision in this species.