Response of neurons in the cat's lateral geniculate nucleus to moving bars of different length.

It is well recognized that in the visual cortex of the cat, some of the cells (hypercomplex) are sharply tuned for the length of a bar moving backwards and forwards across their receptive fields. Other cells (simple) exhibit no such tuning but appear to respond proportionately over a range of bar lengths. The tuning seen in hypercomplex cells is already observable to a lesser degree in retinal ganglion cells. Our experiments were carried out to determine the extent of this tuning in the lateral geniculate nucleus, which relays information from the retina to the cortex. Results show that geniculate cells have tuning properties intermediate between those of ganglion cells and hypercomplex cells. By adding together a linear array of geniculate cells, it is possible to model the characteristics of a simple cell and to demonstrate that while an elongated bar gives a minimal response in hypercomplex cells, it should have little effect on the response of simple cells.