PMID- 1599145
OWN - NLM
STAT- MEDLINE
DCOM- 19920709
LR  - 20190616
IS  - 0077-8923 (Print)
IS  - 0077-8923 (Linking)
VI  - 656
DP  - 1992 May 22
TI  - Ocular compensation for self-motion. Visual mechanisms.
PG  - 220-32
AB  - In monkeys, 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 semicircular canals and otolith organs, 
      respectively. Two independent visual tracking systems that deal with residual 
      disturbances of gaze are manifest in the two components of the optokinetic 
      response: the indirect or delayed component (OKNd) and the direct or early 
      component (OKNe). We 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 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--like the TVOR--seems to have evolved much more recently in 
      frontal-eyed animals and, we suggest, acts as a backup to the TVOR 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. OKNe shares this sensitivity to absolute depth, consistent with the 
      idea that it 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, which we suggest helps the system to segregate the 
      object of regard from other elements in the scene. However, there are occasions 
      when the global optic flow cannot be resolved into a single vector useful to the 
      oculomotor system (e.g., when the moving observer looks towards the direction of 
      heading). We suggest that on such occasions a third independent tracking 
      mechanism, the smooth pursuit system, is deployed to stabilize gaze on the local 
      feature of interest. In this scheme, the pursuit system has an attentional 
      focusing mechanism that spatially filters the visual motion inputs driving the 
      oculomotor system. The major distinguishing features of the 3 visual tracking 
      mechanisms are summarized in Table 1.
FAU - Miles, F A
AU  - Miles FA
AD  - Laboratory of Sensorimotor Research, National Eye Institute, National Institutes 
      of Health, Bethesda, Maryland 20892.
FAU - Busettini, C
AU  - Busettini C
LA  - eng
PT  - Journal Article
PT  - Review
PL  - United States
TA  - Ann N Y Acad Sci
JT  - Annals of the New York Academy of Sciences
JID - 7506858
SB  - IM
MH  - Animals
MH  - Haplorhini
MH  - Head
MH  - Humans
MH  - Models, Biological
MH  - *Movement
MH  - *Reflex, Vestibulo-Ocular
MH  - Retina/physiology
MH  - Vestibule, Labyrinth/physiology
MH  - *Vision, Ocular
RF  - 79
EDAT- 1992/05/22 00:00
MHDA- 1992/05/22 00:01
CRDT- 1992/05/22 00:00
PHST- 1992/05/22 00:00 [pubmed]
PHST- 1992/05/22 00:01 [medline]
PHST- 1992/05/22 00:00 [entrez]
AID - 10.1111/j.1749-6632.1992.tb25211.x [doi]
PST - ppublish
SO  - Ann N Y Acad Sci. 1992 May 22;656:220-32. doi: 
      10.1111/j.1749-6632.1992.tb25211.x.