Visual perception of movement, and the distinction between "object" movement and "background" stability, is dependent upon: (a) the temporal and spatial characteristics of the retinal image; (b) neural discharges originating in non-visual brain areas and operating in parallel with the oculomotor outflow. Data obtained from neurophysiological studies with acute and chromic cats indicate that many visual illusions, resulting in a faulty interpretation of movement direction, speed and background stability, have their basis in the neural organization of the brainstem visual centers. Thus, many movement sensitive cells in the superior colliculus do not have a uniquely defined response to a given velocity (speed and direction) of pattern movement. Rather, such cells exhibit changes in their velocity turning curves (curves relating cell responses to pattern velocities) with different pattern combinations, as for instance in "stimulus'background" situations where one "background" pattern is substituted for another. Furthermore, unit recordings from selected portions of the frontal lobes (frontal eye fields, FEF) have shown that the frequency of FEF cell discharges is modulated in near synchrony with voluntary saccadic eye movements; and that suitably timed electrical shocks, delivered to the FEF in near-synchrony with retinal light stimuli, can characteristically modify the visually evoked responses of single movement sensitive cells in the brainstem superior colliculus. The applied significance of these results rests on the demonstration that a complex visual percept is more than a simple sum of individual stimulus pattern components; and that the neural responses to complex patterns of movement (and consequently the perceptual correlates) cannot be predicted solely from a knowledge of the isolated components of the light stimulus. /Author/SRIS/

  • Supplemental Notes:
    • Proceedings of First International Congress on Vision and Road Safety, Paris, France, February 11-13, 1975.
  • Corporate Authors:

    International Association for Accident and Traffic Medicine

    Huddinge University Hospital Center, Traffic Medicine Center
    Stockholm,   Sweden  141 86
  • Authors:
    • Guitton, D
    • Mandl, G
  • Publication Date: 1975-2

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Filing Info

  • Accession Number: 00153837
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Sep 20 1977 12:00AM