Ja. Buttnerennever et al., EFFERENT PATHWAYS OF THE NUCLEUS OF THE OPTIC TRACT IN MONKEY AND THEIR ROLE IN EYE-MOVEMENTS, Journal of comparative neurology, 373(1), 1996, pp. 90-107
To clarify the role of the pretectal nucleus of the optic tract (NOT)
in ocular following, we traced NOT efferents with tritiated leucine in
the monkey and identified the cell groups they targeted. Strong local
projections from the NOT were demonstrated to the superior colliculus
and the dorsal terminal nucleus bilaterally and to the contralateral
NOT. The contralateral oculomotor complex, including motoneurons (C-gr
oup) and subdivisions of the Edinger-Westphal complex, also received i
nputs. NOT efferents terminated in all accessory optic nuclei (AON) ip
silaterally; contralateral AON projections arose from the pretectal ol
ivary nucleus embedded in the NOT. Descending pathways contacted prece
rebellar nuclei: the dorsolateral and dorsomedial pontine nuclei, the
nucleus reticularis tegmenti pontis, and the inferior olive. Direct pr
ojections from NOT to the ipsilateral nucleus prepositus hypoglossi (p
pH) appeared to be weak, but retrograde tracer injections into rostral
ppH verified this projection; furthermore, the injections demonstrate
d that AON efferents also enter this area. Efferents from the NOT also
targeted ascending reticular networks from the pedunculopontine tegme
ntal nucleus and the locus coeruleus. Rostrally, NOT projections inclu
ded the magnocellular layers of the lateral geniculate nucleus (Ign);
the pregeniculate, peripeduncular, and thalamic reticular nuclei; and
the pulvinar, the zona incerta, the mesencephalic reticular formation,
the intralaminar thalamic nuclei, and the hypothalamus. The NOT could
generate optokinetic nystagmus through projections to the AON, the pp
H, and the precerebellar nuclei. However, NOT also projects to structu
res controlling saccades, ocular pursuit, the near response, Ign motio
n sensitivity, visual attention, vigilance, and gain modification of t
he vestibule-ocular reflex. Any hypothesis on the function of NOT must
take into account its connectivity to all of these visuomotor structu
res. (C) 1996 Wiley-Liss, Inc.