title: Integration and segregation of multiple motion signals by neurons in area MT of primate.
abstract: We used multielectrode arrays to measure the response of populations of neurons in primate middle temporal area to the transparent motion of two superimposed dot fields moving in different directions. The shape of the population response was well predicted by the sum of the responses to the constituent fields. However, the population response profile for transparent dot fields was similar to that for coherent plaid motion and hence an unreliable cue to transparency. We then used single-unit recording to characterize component and pattern cells from their response to drifting plaids. Unlike for plaids, component cells responded to the average direction of superimposed dot fields, whereas pattern cells could signal the constituent motions. This observation provides support for a strong prediction of the Simoncelli and Heeger (1998) model of motion analysis in area middle temporal, and suggests that pattern cells have a special status in the processing of superimposed dot fields.
authors.affiliation: ARC Centre of Excellence in Vision Science, The University of Sydney, New South Wales, Australia;
authors.forename: J Scott
authors.initials: JS
authors.lastname: McDonald
authors.forename: Colin W G
authors.initials: CW
authors.lastname: Clifford
authors.forename: Selina S
authors.initials: SS
authors.lastname: Solomon
authors.forename: Spencer C
authors.initials: SC
authors.lastname: Chen
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Solomon
mesh_terms: D000200:Action Potentials; D000818:Animals; D002144:Callithrix; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology*; D013702:Temporal Lobe / Q000166:cytology / Q000502:physiology*; D014796:Visual Perception
keywords: extrastriate cortex; plaid; population coding; transparency; vision