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Oliver Layton, Brett Fajen; A neural model of MST and MT explains perceived object motion during self-motion. Journal of Vision 2016;16(12):399. doi: 10.1167/16.12.399.
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© 2017 Association for Research in Vision and Ophthalmology.
To avoid collisions, predation, and other life-threatening encounters, humans must perceive the motion of objects that move independently during self-motion. The local optical motion of such objects on the retina depends not only on their movement through the world, but also on the observer's self-motion (observer-relative reference frame). Yet, there is compelling evidence that humans perceive the object motion in a world-relative reference frame, that is at most weakly affected by self-motion (Matsumiya & Ando, 2009, Rushton & Warren, 2005; Warren & Rushton, 2009). The visual system must somehow transform the observer-relative motion on the retina to a world-relative reference frame. The importance of this problem has inspired research on the visual conditions in which object motion is recovered, but the underlying mechanisms in the visual system remain unclear. We present a simple model that makes explicit possible mechanisms in visual cortex by which self-motion signals in area MST interact with object motion signals in area MT to recover the world-relative motion of an object. The model relies on two mechanisms to explain and unify existing data. First, feedback from MSTd cells inhibits MT cells that signal motion that is inconsistent with the global flow pattern, which biases the direction coded by the MT population toward that of the object in a world-relative reference frame. Second, local antagonism between MT cells tuned in opponent motion directions leads to rebound activity that further shifts the MT population response toward the object's world-relative direction. Our analysis reveals the proportion that global and local mechanisms contribute in the recovery of world-relative object motion. The model clarifies the means by which self-motion and object motion signals might interact and offers a new hypothesis about the connection between heading and the recovery of object motion in a world reference frame.
Meeting abstract presented at VSS 2016
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