PMID- 8420560
OWN - NLM
STAT- MEDLINE
DCOM- 19930218
LR  - 20051116
IS  - 0168-8375 (Print)
IS  - 0168-8375 (Linking)
VI  - 5
DP  - 1993
TI  - The sensing of rotational and translational optic flow by the primate optokinetic 
      system.
PG  - 393-403
AB  - In primates, there are several reflexes that generate eye movements to compensate 
      for the observer's own movements. Two vestibuloocular reflexes compensate 
      selectively for rotational (RVOR) and translational (TVOR) disturbances of the 
      head, receiving their inputs from the semi-circular canals and otolith organs, 
      respectively. Two independent visual tracking systems deal with any residual 
      disturbances of gaze (global optic flow) and are manifest in the two components 
      of the optokinetic response: the indirect or delayed component (OKNd) and the 
      direct or early component (OKNe). I hypothesize that OKNd--like the RVOR--is 
      phylogenetically old, being found in all animals with mobile eyes, and that it 
      evolved as a backup to the RVOR to compensate for residual rotational 
      disturbances of gaze. Indeed, optically induced changes in the gain of the RVOR 
      result in parallel changes in the gain of OKNd, consistent with the idea of 
      shared pathways as well as shared functions. In contrast, OKNe seems to have 
      evolved much more recently in frontal-eyed animals and, I suggest, acts as a 
      backup to the TVOR--also recently evolved?--to deal primarily with translational 
      disturbances of gaze. Frontal-eyed animals with good binocular vision must be 
      able to keep both eyes directed at the object of regard irrespective of proximity 
      and, in order to achieve this during translational disturbances, the output of 
      the TVOR is modulated inversely with the viewing distance. This sensitivity to 
      absolute depth is also shared by OKNe, consistent with the idea that OKNe is 
      synergistic with the TVOR and shares some of its central pathways. There is 
      evidence that OKNe is also sensitive to relative depth cues such as motion 
      parallax and disparity, which I suggest help the system to segregate the object 
      of regard from other elements in the scene. I also suggest that highly complex 
      optic flow patterns (such as those experienced by the moving observer who looks a 
      little off to one side of his direction of heading) are dealt with by a third 
      visual tracking mechanism--the smooth pursuit system--that spatially filters 
      visual motion inputs so as to exclude all but the motion of the object of 
      interest (local optic flow).
FAU - Miles, F A
AU  - Miles FA
AD  - Laboratory of Sensorimotor Research, National Eye Institute, National Institutes 
      of Health, Bethesda, MD 20892.
LA  - eng
PT  - Journal Article
PT  - Review
PL  - Netherlands
TA  - Rev Oculomot Res
JT  - Reviews of oculomotor research
JID - 8506449
SB  - IM
MH  - Animals
MH  - Macaca/*physiology
MH  - Neural Pathways/*physiology
MH  - Nystagmus, Optokinetic/*physiology
MH  - Optic Nerve/*physiology
MH  - Pursuit, Smooth/physiology
MH  - Reflex, Vestibulo-Ocular/*physiology
MH  - Visual Perception/physiology
RF  - 49
EDAT- 1993/01/01 00:00
MHDA- 1993/01/01 00:01
CRDT- 1993/01/01 00:00
PHST- 1993/01/01 00:00 [pubmed]
PHST- 1993/01/01 00:01 [medline]
PHST- 1993/01/01 00:00 [entrez]
PST - ppublish
SO  - Rev Oculomot Res. 1993;5:393-403.