Ci. Kolmac et J. Mitrofanis, ORGANIZATION OF THE RETICULAR THALAMIC PROJECTION TO THE INTRALAMINARAND MIDLINE NUCLEI IN RATS, Journal of comparative neurology, 377(2), 1997, pp. 165-178
This study examines the projection of the reticular thalamic nucleus t
o the classic ''nonspecific'' dorsal thalamic nuclei of rats. Individu
al nuclei of the intralaminar (central-lateral, paracentral, central-m
edial, parafascicular) and the midline (reuniens/rhomboid, parataenial
) nuclear groups, together with the reticular nucleus itself, were inj
ected with the neuronal tracers biotinylated dextran or fluorescent la
tex microspheres (red or green). Reticular cells projecting to the int
ralaminar and midline nuclei are limited largely to the rostral pole o
f the nucleus. Within the rostral pole, most reticular cells projectin
g to the intralaminar and midline nuclear groups are found in largely
distinct sectors; cells that project to the intralaminar nuclei tend t
o lie more laterally, whereas those projecting to the midline nuclei l
ie more medially within the pole. Among the individual nuclei of both
the intralaminar and midline nuclear groups, however, the segregation
is far less distinct. For instance, the reticular cells that project t
o the intralaminar central-lateral, central-medial, paracentral, and p
arafascicular nuclei are intermixed completely on the lateral edge of
the rostral pole. After separate injections of different colored latex
microspheres into individual intralaminar nuclei, the incidence of do
uble-labelled reticular cells is about 37%, st percentage much higher
than among the ''specific'' dorsal thalamic nuclei (<1%). All the abov
e-mentioned results refer to the reticular labelling seen on the side
ipsilateral to the injection. After separate injections into the intra
laminar central-medial nucleus, the midline nuclei, and the reticular
nucleus itself, we also see a very small group of reticular cells labe
lled on the contralateral side. In general, our results indicate that
the reticular projection to the intralaminar and midline nuclei is far
more diffuse than the reticular projection to the specific dorsal tha
lamic nuclei. (C) 1997 Wiley-Liss, Inc.