Contour integration in the primary visual cortex of the opossum.
To investigate whether contour integration is a generalized mammalian feature we studied single cells in V1 on the South-America opossum ( ), a plesiomorphic animal believed to retain basic characteristics of early mammals. We observed that when a cell's receptive field (RF) was masked (i.e. an artificial scotoma was produced), sweeping a long bar (several times the length of the RF) at the cell's preferred orientation elicited robust responses in many cells (28/103, or 27%). Therefore, some cells in the primary visual cortex of the opossum interpolate under conditions consistent with physical occlusion. The present results indicate that the property of contour integration appears to be a basic property of the mammalian visual system.
Oliveira
Leticia
L
Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, CCS-BL. G-UFRJ, Ilha do Fundão, Rio de Janeiro, 21949-900, Brazil. ldol@nitnet.com.br
Volchan
Eliane
E
Pessoa
Luiz
L
Pantoja
Janaina H
JH
Joffily
Mateus
M
Souza-Neto
David
D
Marques
Rodrigo F
RF
Rocha-Miranda
Carlos Eduardo
CE
D000818:Animals; D004594:Electrophysiology; D005556:Form Perception / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009893:Opossums; D009949:Orientation; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology