RESUMO
A total of 287 neurons were antidromically driven in quasi-cortical regions, i.e., anterior olfactory nucleus (24%), basolateral amygdala (13%), main olfactory bulb (4%), prefrontal cortex (37%), and in the hippocampal formation (22%) following macro- and microstimulation of the rat's ventrostriopallidal region (VSPR). In addition, a substantial number of units (n = 175) were also transynaptically affected in all these structures by shocks delivered to the VSPR. Excitatory effects were detected in 50 neurons (56.1% of responsive cells), 36 cells (40.4%) responding with inhibition of spontaneous discharges. Conversely, stimulation of cortical and quasi-cortical regions antidromically discharged (n = 37) or transynaptically affected (n = 151) units in the VSPR; 168 neurons were not responsive to VSPR stimulation. Axon collateralization (branching) of 14 neurons in anterior olfactory nucleus, basolateral amygdala, and hippocampal formation was revealed with the use of the reciprocal collision test. Conduction properties of 35 neurons, evaluated by paired-pulse stimulation, indicated that only 26% showed a significant increase in conduction velocity and a decrease in threshold during the supernormal phase. The present findings confirm and extend previous neuroanatomical studies that have, first, described strong interconnections between the neocortex and striatal structures, and second, that the VSPR as suggested by previous structural, hodological, and histochemical studies, seems to maintain a more close relationship with olfactory related structures than hitherto suspected.
Assuntos
Córtex Cerebral/fisiologia , Globo Pálido/fisiologia , Neostriado/fisiologia , Animais , Axônios/fisiologia , Gânglios da Base/fisiologia , Temperatura Corporal/fisiologia , Córtex Cerebral/anatomia & histologia , Condicionamento Psicológico/fisiologia , Estimulação Elétrica , Espaço Extracelular/fisiologia , Globo Pálido/anatomia & histologia , Neostriado/anatomia & histologia , Condução Nervosa/fisiologia , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Ratos , Ratos Wistar , Técnicas EstereotáxicasRESUMO
Antidromic unit driving was utilized to demonstrate afferent projections from prefrontal cortical (PFC) and quasi-cortical structures (main olfactory bulb, MOB; anterior olfactory nucleus, AON; basolateral amygdaloid nucleus, BLA) to the ventrostriopallidal region (VSPR) of the rat. In all regions explored, a substantial number of antidromically invaded neurons were found following electrical stimulation of the VSPR. In addition, both the AON and the amygdalostriatal zone harbor cells with branched axons which innervate the MOB and the VSPR and the agranular insular cortex and the VSPR, respectively. These results support and extend previous neuroanatomical and neurophysiological data on afferent connections of the VSPR and emphasize the fact that several regions of the basal forebrain, which are actively involved in processing of olfactory information, and the VSPR, are more closely interrelated than hitherto suspected.