Abstract
The [14C]2-deoxyglucose (2-DG) method was used to identify those structures in the central visual system of Rana pipiens showing increased metabolic activity during binocular and monocular optokinetic stimulation at two pattern velocities (2 deg/sec and 9 deg/sec). Analysis of autoradiograms made with computer-assisted microdensitometry and pseudocolor image-enhancement techniques revealed that the greatest uptake of 2-DG occurred in the pretectal region, which included the large-celled nucleus lentiformis mesencephali (nLM), nucleus pretectalis, and pretectal gray. Both temporal-to-nasal (T-N) and nasal to temporal (N-T) directions of pattern motion were correlated with high levels of 2-DG uptake. However, the nucleus of the basal optic root (nBOR) showed the greatest uptake of 2-DG for the N-T direction, which evokes little or no optokinetic (OKN) response in this species. These results suggest that the major efferent projection from nBOR to nLM may exert its greatest effect upon the ipsilateral pretectum during N-T stimulation. Other regions showing substantial 2-DG uptake included a large region of the ventral thalamus, for all stimulus conditions tested, including those cell groups associated with the retinorecipient neuropil, corpus geniculatum. The pattern of uptake was less closely associated with specific parameters of optokinetic stimulation than was observed in the pretectum and accessory optic nucleus. Like nBOR, the auricular lobe of the cerebellum also showed greatest uptake of 2-DG for the N-T, monocular stimulus condition. The neural circuitry that underlies OKN and its directional asymmetry during monocular stimulation appears to involve a number of structures whose functional interrelationships are yet to be described.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.