A retino-mesotelencephalic pathway in the rat.

We have demonstrated a disynaptic pathway in the adult rat that connects retinal ganglion cells with the anteromedial portion of the caudate-putamen and with the prefrontal and anterior cingulate cortex through the ventral midbrain tegmentum. This retino-mesotelencephalic pathway has been revealed by double-labeling methods in which neurons located in the medial portion of the pars compacta of the substantia nigra and the lateral portion of the nucleus paranigralis of the ventral tegemental area have been retrogradely labeled with tracers injected into the anteromedial portion of the caudate-putamen or the prefrontal/anterior cingulate cortex and have been anterogradely, and transynaptically, labeled with [3H]adenosine injected into the eye. The data show a disynaptic connection from retinal ganglion cells to striatal and cortical neurons by which direction and velocity specific visual information may affect visually guided motor behavior.