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Pattern in the laminar origin of corticocortical connections
Author(s) -
Barbas H.
Publication year - 1986
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.902520310
Subject(s) - somatosensory system , neuroscience , biology , laminar organization , horseradish peroxidase , anatomy , laminar flow , axoplasmic transport , afferent , cortex (anatomy) , frontal lobe , physics , biochemistry , thermodynamics , enzyme
The laminar origin of cortical projections to the frontal cortex was studied in 17 adult rhesus monkeys with the use of the retrograde transport of horseradish peroxidase (HRP). The frontal regions injected with HRP extended from the posterior periarcuate region to the frontal pole. The architectonic boundaries of areas containing HRP‐labeled neurons were determined from matched sections stained for the visualization of cell bodies, myelin, or acetylcholinesterase. The results showed that the laminar origin of both nearby and distant corticocortical projections was correlated with the architectonic differentiation of the regions giving rise to the projecting afferent fibers. Frontally directed projections from limbic cortices, which show a redimentary laminar organization, emanated mainly from deep layers. On the other hand, projections from increasingly more differentiated cortices arose progressively from the upper (or superagranular) layers. This pattern was observed for projections originating along the axis of architectonic differentiation of the visual, somatosensory, auditory, motor, and preforntal cortical systems. Thus, as the cortical architecture within each system changes from limbic areas toward the primary cortices, the origin of frontally directed projections shifts from predominantly infragranular to predominantly superagranular layers.