Da. Ruggiero et al., VISCERAL AFFERENT PATHWAYS TO THE THALAMUS AND OLFACTORY TUBERCLE - BEHAVIORAL-IMPLICATIONS, Brain research, 799(1), 1998, pp. 159-171
The goal of this study was to support the hypothesis that visceral sig
nals may integrate and influence behavior by way of direct pathways fr
om the nucleus tractus solitarii (NTS) to the olfactory tubercle and t
he midline/intralaminar thalamus. An anterograde tracer, biotinylated
dextran amine (BDA) was iontophoresed bilaterally into the caudal NTS
to optimize terminal labeling. NTS-cortical projections traversed both
limbs of the diagonal bands providing heavy innervation, and terminat
ed lightly within layer 3 of the olfactory tubercle. NTS-thalamic proj
ections terminated within anterior and, as previously shown, posterior
divisions of nucleus paraventricularis thalami and avoided the adjoin
ing mediodorsal thalamic nucleus. Heretofore unrecognized projections
were traced to the parafascicular and reuniens thalamic nuclei, and th
e peripeduncular nucleus. Control experiments identified the nucleus g
racilis as the principal source of ascending projections to ventropost
erior lateral, posterior and intralaminar thalamic nuclei. Our data co
rroborate the supposition that olfactory signals may integrate with vi
sceral stimuli in the striatal compartment of olfactory tubercle. NTS
projections encompass thalamic nuclei that project topographically to
the prefrontal cortex, hippocampus and ventral (limbic) striatum, regi
ons activated by visceral stimulation. Structural data support the ide
a that compartments of the non-discriminative thalamus may contribute
to perception and behavioral responses to visceral stimulation. (C) 19
98 Published by Elsevier Science B.V. All rights reserved.