title: The parvocellular LGN provides a robust disynaptic input to the visual motion area MT.
abstract: Dorsal visual cortical areas are thought to be dominated by input from the magnocellular (M) visual pathway, with little or no parvocellular (P) contribution. These relationships are supported by a close correlation between the functional properties of these areas and the M pathway and by a lack of anatomical evidence for P input. Here we use rabies virus as a retrograde transynaptic tracer to show that the dorsal area MT receives strong input, via a single relay, from both M and P cells of the lateral geniculate nucleus. This surprising P input, likely relayed via layer 6 Meynert cells in primary visual cortex, can provide MT with sensitivity to a more complete range of spatial, temporal, and chromatic cues than the M pathway alone. These observations provide definitive evidence for P pathway input to MT and show that convergence of parallel visual pathways occurs in the dorsal stream.
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Nassi
authors.forename: David C
authors.initials: DC
authors.lastname: Lyon
authors.forename: Edward M
authors.initials: EM
authors.lastname: Callaway
mesh_terms: D000818:Animals; D005829:Geniculate Bodies / Q000033:anatomy & histology* / Q000502:physiology; D008251:Macaca; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D013569:Synapses / Q000502:physiology; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000502:physiology; D014795:Visual Pathways / Q000033:anatomy & histology* / Q000502:physiology