Projections from cortical visual areas 17, 18, and MT onto the dorsal lateral geniculate nucleus in owl monkeys

Projections from cortical visual Areas 17, 18, and MT to the dorsal lateral geniculate nucleus of owl monkeys were revealed by the use of the autoradiographic tracing method. Restricted injections of 3H-proline into Area 17 resulted in dense columns of labeled tissue extending through all layers of the nucleus and roughly perpendicular to the layers. There was some lateral spread of the label in the interlaminar zones. Projections from Areas 18 and MT were distributed over the ventral layers of the nucleus including the magnocellular layers, layer S, and the adjoining interlaminar zones. The input from Area 18 was relatively sparse. The projections from all three cortical visual areas appear to connect homotopic locations in the geniculate and cortical representations of the visual field.