The pretectal nucleus of the optic tract modulates the direction selectivity of accessory optic neurons in rats.

Direction-selective single units within the medial terminal nucleus of the rat were shown to prefer motion in upward-temporal or downward-nasal directions. Lesions of the optic tract nucleus practically abolished responses to the nasal direction of motion and increased the directional bias toward the temporal direction. Such results suggest a significant role of that pretectal nucleus in the determination of direction selectivity of accessory optic neurons.