Effects of stimulus spatial frequency, size, and luminance contrast on orientation tuning of neurons in the dorsal lateral geniculate nucleus of cat.

•We studied responses of cat LGN neurons to large and high spatial frequency gratings.•More than 90% of LGN neurons exhibited significant orientation selectivity.•Both an elongated receptive field and surround suppression contributed to the selectivity.•The orientation tuning of LGN neurons showed a stimulus-contrast invariant property.•GABAA inhibition seemed to enhance the orientation selectivity in the LGN.