Receptive field dimensions of lateral geniculate cells in the common marmoset (Callithrix jacchus).

We measured the spatial receptive field dimensions of cells in the lateral geniculate nucleus (LGN) of the common marmoset (Callithrix jacchus) using a bipartite field stimulus in which the two halves of the field were modulated identically but in counterphase. Horizontal and vertical edges between the two fields were positioned at different locations in the receptive field. By assuming that centers and surrounds have gaussian profiles, we were able to obtain a satisfactory mathematical description of the data. Receptive field centers were about a factor 1.6 larger than those of macaque LGN cells, in accordance with the smaller marmoset eye. There was a limited correspondence with dendritic tree dimensions of marmoset retinal ganglion cells. We further found that center and surround gaussians were not always concentric, and that the centers of some cells were elongated. This might allow some direction or orientation biases in LGN cells.