Journal of Neurophysiology, Vol 43, Issue 2 355-366, Copyright © 1980 by APS
Visual pontocerebellar projections in the cat
G. Mower, A. Gibson, F. Robinson, J. Stein and M. Glickstein
1. Projections of pontine visual cells onto the cat cerebellar cortex were
studied by antidromic activation and by the retrograde transport of
horseradish peroxidase (HRP). 2. Cells in the medial pontine visual area,
which receive visual cortex projections, were activated antidromically
principally from the contralateral cerebellar hemisphere. Cells in the
dorsolateral pontine visual area, which receive an input from the superior
colliculus, were activated principally from the vermis and ipsilateral
hemisphere. There is some overlap in the projections of these two different
populations of pontine cells, which probably occurs by way of bifurcated
axons. 3. The HRP technique confirmed that there is a major difference in
the pattern of projections from these two pontine visual regions. Many
cells in the rostral-medial portion of the pontine nuclei, which receive
their input from visual cortex, were labeled following HRP injections in
the contralateral cerebellar hemisphere. Far fewer of these cells were
labeled following vermal injection. Cells in the dorsolateral pontine
nucleus, which receive visual input from the superior colliculus, were
labeled following an HRP injection in the vermis or the ipsilateral
hemisphere. Cells in the region of pontine nuclei that receive input from
the ventral lateral geniculate nucleus were also labeled after a vermian
injection. 4. If the vermis is related to the control of whole-body
movements and the hemisphere to control of ipsilateral limbs, these results
suggest that the corticopontocerebellar and the tectopontocerebellar
pathways may be involved in different classes of visually guided movement.
