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Prefrontal cortical projections to the cholinergic neurons in the basal forebrain
Author(s) -
Gaykema Ronald P. A.,
Van Weeghel Rob,
Hersh Louis B.,
Luiten Paul G. M.
Publication year - 1991
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903030405
Subject(s) - basal forebrain , prefrontal cortex , neuroscience , cholinergic neuron , choline acetyltransferase , biology , cholinergic , diagonal band of broca , basal ganglia , forebrain , anatomy , central nervous system , cognition
Abstract The prefrontal cortex (PFC) projections to the basal forebrain cholinergic cell groups in the medial septum (MS), vertical and horizontal limbs of the diagonal band of Broca (VDB and HDB), and the magnocellular basal nucleus (MBN) in the rat were investigated by anterograde transport of Phaseolus vulgaris leuco‐agglutinin (PHA‐L) combined with acetylcholinesterase (AChE) histochemistry or choline acetyltransferase (ChAT) immunocytochemistry. The experiments revealed rich PHA‐L‐labeled projections to discrete parts of the basal forebrain cholinergic system (BFChS) essentially originating from all prefrontal areas investigated. The PFC afferents to the BFChS display a topographic organization, such that medial prefrontal areas project to the MS, VDB, and the medial part of the HDB, whereas the orbital and agranular insular areas predominantly innervate the HDB and MBN, respectively. Since the recurrent BFChS projection to the prefrontal cortex is arranged according to a similar topography, the relationship between the BFChS and the prefrontal cortex is characterized by reciprocal connections. Furthermore, tracer injections in the PFC resulted in anterograde labeling of numerous “en passant” and terminal boutons apposing perikarya and proximal dendrites of neurons in the basal forebrain, which were stained for the cholinergic marker enzymes. These results indicate that prefrontal cortical afferents make direct synaptic contacts upon the cholinergic neurons in the basal forebrain, although further analysis at the electron microscopic level will be needed to provide conclusive evidence.