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Metabolic correlates of optokinetic stimulation in the central visual system of the frog, Rana pipiens
Author(s) -
Fite Katherine V.,
Bengston Lynn,
Taggert Gregory,
Montgomery Neil,
Tyler Christopher
Publication year - 1992
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903160406
Subject(s) - pretectal area , optokinetic reflex , biology , stimulation , monocular , nucleus , efferent , neuroscience , anatomy , stimulus (psychology) , thalamus , visual system , photic stimulation , cerebellum , midbrain , central nervous system , vestibular system , visual perception , visual cortex , psychology , physics , afferent , optics , perception , psychotherapist
The [ 14 C]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 pretectuni 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.