Cortical projections to the nucleus of the optic tract and dorsal terminal nucleus and to the dorsolateral
pontine nucleus in macaques: a dual retrograde tracing study.
C. Distler, M.J. Mustari & K.-P. Hoffmann
The Journal of Comparative Neurology, 444: 144-158,2002
- The nucleus of the optic tract and dorsal terminal nucleus of the accessory optic system (NOT-DTN) along with
the dorsolateral pontine nucleus (DLPN) have been shown to play a role in controlling slow eye movements and in
maintaining stable vision during head movements. Both nuclei are known to receive cortical input from striate and
extrastriate cortex. To determine to what degree this cortical input arises from the same areas and potentially
from the same individual neurons, we placed different retrograde tracers into the NOT-DTN and the DLPN. In the
ipsilateral cortical hemisphere the two projections mainly overlapped in the posterior part of the superior temporal
sulcus (STS) comprising the middle temporal area (MT), the middle superior temporal area (MST), and the visual
area in the fundus of the STS (FST) and the surrounding cortex. In these areas, neurons projecting to the NOT-DTN
or the DLPN were closely intermingled. Nevertheless, only 3-11% of the labeled neurons in MT and MST were double-labeled
in our various cases. These results indicate that the cortical input to the NOT-DTN and DLPN arises from largely
separate neuronal subpopulations in the motion sensitive areas in the posterior STS. Only a small percentage of
the projection neurons bifurcate to supply both targets. These findings are discussed in relation to the optokinetic
and the smooth pursuit system.
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