The Journal of Neuroscience, April 21, 2004, 24(16):4061-4069; doi:10.1523/JNEUROSCI.0903-04.2004
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Behavioral/Systems/Cognitive
Optokinetic Deficits in Albino Ferrets (Mustela putorius furo): A Behavioral and Electrophysiological Study
Klaus-Peter Hoffmann,
Nicolaos Garipis, and
Claudia Distler
Allgemeine Zoologie und Neurobiologie, Ruhr-Universität Bochum, Postfach 102148, D-44780 Bochum, Germany
We compared the horizontal optokinetic reaction (OKR) and response properties of retinal slip neurons in the nucleus of the optic tract and dorsal terminal nucleus (NOT-DTN) of albino and wild-type ferrets (Mustela putorius furo). In contrast to pigmented ferrets, we were unable to observe OKR in albino ferrets during binocular and monocular viewing using random dot full field stimulation and electro-oculography (EOG). Observations during early postnatal life indicate that regular OKR is present in pigmented pups 3 d after eye opening but is absent at any stage during development in albino ferrets. Unilateral muscimol injections to inactivate all neurons in the NOT-DTN containing GABAA and GABAC receptors caused spontaneous horizontal nystagmus with slow phases away from the injected hemisphere in albino as well as in pigmented animals. Retinal slip neurons in the NOT-DTN of albino ferrets identified by antidromic activation from the inferior olive and orthodromic activation from the optic chiasm were well responding to intermittent bright light stimuli, but many showed a profound reduction of responsiveness to moving stimuli. The movement-sensitive neurons exhibited no clear direction selectivity for ipsiversive stimulus movement, a characteristic property of these neurons in pigmented ferrets and other mammals. Thus, the defect rendering albino ferrets optokinetically nonresponsive is located in the visual pathway subserving the OKR, namely in or before the NOT-DTN, and not in oculomotor centers.
Key words: optokinetic reaction; retinal slip neurons; nucleus of the optic tract; dorsal terminal nucleus of the accessory optic system; muscimol inactivation; antidromic activation
Received Aug 30, 2003;
accepted March 12, 2004.
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R. Philipp, C. Distler, and K.-P. Hoffmann
A Motion-sensitive Area in Ferret Extrastriate Visual Cortex: an Analysis in Pigmented and Albino Animals
Cereb Cortex,
June 1, 2006;
16(6):
779 - 790.
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