The Journal of Neuroscience, August 1, 1998, 18(15):5958-5975
Emulating the Visual Receptive-Field Properties of MST Neurons
with a Template Model of Heading Estimation
John A.
Perrone1 and
Leland S.
Stone2
1 Department of Psychology, University of Waikato,
Hamilton, New Zealand, and 2 Human Information Processing
Research Branch, NASA Ames Research Center, Moffett Field, California
We have proposed previously a computational neural-network model by
which the complex patterns of retinal image motion generated during
locomotion (optic flow) can be processed by specialized detectors
acting as templates for specific instances of self-motion. The
detectors in this template model respond to global optic flow by
sampling image motion over a large portion of the visual field through
networks of local motion sensors with properties similar to those of
neurons found in the middle temporal (MT) area of primate extrastriate
visual cortex. These detectors, arranged within cortical-like maps,
were designed to extract self-translation (heading) and self-rotation,
as well as the scene layout (relative distances) ahead of a moving
observer. We then postulated that heading from optic flow is directly
encoded by individual neurons acting as heading detectors within the
medial superior temporal (MST) area. Others have questioned whether
individual MST neurons can perform this function because some of their
receptive-field properties seem inconsistent with this role. To resolve
this issue, we systematically compared MST responses with those of
detectors from two different configurations of the model under matched
stimulus conditions. We found that the characteristic physiological
properties of MST neurons can be explained by the template model. We
conclude that MST neurons are well suited to support self-motion
estimation via a direct encoding of heading and that the template model
provides an explicit set of testable hypotheses that can guide future
exploration of MST and adjacent areas within the superior temporal
sulcus.
Key words:
self-motion perception; navigation; optic flow; gaze
stabilization; monkey; vision
Copyright © 1998 Society for Neuroscience 0270-6474/98/18155958-18$05.00/0
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