title: Sensitivity of the avian motion system to light and dark stimuli.
abstract: Global motion perception is important for mobile organisms. In laterally eyed birds, global motion appears to be processed in the entopallium, a neural structure that is part of the tectofugal pathway. Electrophysiological research has shown that motion selective cells in the entopallium are most responsive to small dark moving targets. Here, we investigated whether this bias toward dark targets of entopallial cells is mirrored by perceptual performance in a motion detection task in pigeons. We measured the detection thresholds of pigeons using random dot stimuli that consisted of either black or white dots on a gray background. We found that thresholds were significantly lower when using black dots as opposed to white dots. This heightened sensitivity is also noted in the learning rates of the pigeons. That is, we found that the pigeons learned the detection task significantly faster when the stimuli consisted of black dots. We believe that our results have important implications for the understanding of the functional role of the entopallium and the ON and OFF pathways in the avian motion system.
authors.affiliation: Department of Psychology, University of Alberta, P217 Biological Sciences Bldg, Edmonton, AB, T6G 2E9, Canada. nankoo@ualberta.ca.
authors.forename: Jean-François
authors.identifier: 0000-0003-2697-4885
authors.initials: JF
authors.lastname: Nankoo
authors.affiliation: Department of Psychology, University of Alberta, P217 Biological Sciences Bldg, Edmonton, AB, T6G 2E9, Canada.|Department of Psychology, Boston College, Chestnut Hill, MA, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Madan
authors.affiliation: Department of Psychology, University of Alberta, P217 Biological Sciences Bldg, Edmonton, AB, T6G 2E9, Canada.
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Spetch
authors.affiliation: Department of Psychology, University of Alberta, P217 Biological Sciences Bldg, Edmonton, AB, T6G 2E9, Canada.|Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Wylie
mesh_terms: D000818:Animals; D010856:Columbidae / Q000502:physiology*; D015350:Contrast Sensitivity; D003624:Darkness; D008027:Light; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D012684:Sensory Thresholds; D013037:Spatial Behavior / Q000502:physiology*
keywords: Columba livia; Luminance; Motion perception; OFF pathway; ON pathway