Responses of the nucleus of the optic tract neurons projecting to the nucleus reticularis tegmenti pontis upon optokinetic stimulation in the rabbit.
The activity of cells (n = 55) in the nucleus of the optic tract (NOT) in pigmented rabbits was recorded extracellularly. All cells were activated orthodromically from the optic chiasm (latency 2.3 +/- 0.4 ms, mean and S.D., n = 33). The mean conduction velocity of optic nerves to the NOT was 19.0 m/s, and the mean nuclear delay in the NOT was 0.9 ms. Stimulation to the nucleus reticularis tegmenti pontis (Nrtp) antidromically activated 37 cells (latency 1.0 +/- 0.3 ms) (Nrtp(+)cell) but did not antidromically activate the other 18 cells (Nrtp(-) cell). The response properties were studied by spike density histograms constructed during the application of moving visual stimuli (random dot patterns, 0.1-200 degrees/s). The optimal velocity was 5-50 degrees/s for the majority (74%, n = 29) of the total samples tested. Of 10 cells preferring high velocities (75-150 degrees/s), four times as many Nrtp(+) cells (n = 8) preferred high velocities as did Nrtp(-) cells. The optimal velocities of Nrtp(+) cells significantly correlated with the rostro-caudality of recording sites in the NOT, the more rostral cells preferring a slower velocity. Nrtp(+) cells preferred not only a horizontal (53%) but also a vertical or diagonal orientation in contrast to the majority (71%) of Nrtp(-) cells, which preferred a horizontal orientation. The receptive fields (mean size 28 degrees X 15 degrees) scattered horizontally corresponding to the visual streak of the retina.
D000818:Animals; D001931:Brain Mapping; D002531:Cerebellum / Q000502:physiology; D008636:Mesencephalon / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology*; D009760:Nystagmus, Physiologic; D011149:Pons / Q000502:physiology*; D011601:Psychophysics; D011817:Rabbits; D012154:Reticular Formation / Q000502:physiology*; D014794:Visual Fields; D014795:Visual Pathways / Q000502:physiology