TY - JOUR
T1 - Conserved patterns of cortico-cortical connections define areal hierarchy in rat visual cortex
AU - Coogan, T. A.
AU - Burkhalter, A.
PY - 1990/4
Y1 - 1990/4
N2 - The prevalence of reciprocal connections in the cerebral cortex indicates that they play a fundamental role in the processing of sensory information. We have investigated the laminar termination patterns of such paired connections between different visual cortical areas of the rat, and have found two basic projection types: one which includes layer 4 and a second which includes layer 1 and avoids layer 4. The projections from primary visual cortex (area 17) to extrastriate visual cortical targets in the cytoarchitectonical areas 18a and 18b, and from 18a to a site in 18b, are of the first type. In contrast, the return projections from 18a and 18b to area 17 and from 18b to 18a, are of the second type. Thus each pair of connections has one element of each type, giving every circuit a nearly identical asymmetric structure. These laminar patterns resemble those of forward and feedback connections in primate cortex, indicating that cortico-cortical connectivity patterns are highly conserved through evolution, and that, as in monkeys, these connections define a hierarchical organization of areas in rat visual cortex.
AB - The prevalence of reciprocal connections in the cerebral cortex indicates that they play a fundamental role in the processing of sensory information. We have investigated the laminar termination patterns of such paired connections between different visual cortical areas of the rat, and have found two basic projection types: one which includes layer 4 and a second which includes layer 1 and avoids layer 4. The projections from primary visual cortex (area 17) to extrastriate visual cortical targets in the cytoarchitectonical areas 18a and 18b, and from 18a to a site in 18b, are of the first type. In contrast, the return projections from 18a and 18b to area 17 and from 18b to 18a, are of the second type. Thus each pair of connections has one element of each type, giving every circuit a nearly identical asymmetric structure. These laminar patterns resemble those of forward and feedback connections in primate cortex, indicating that cortico-cortical connectivity patterns are highly conserved through evolution, and that, as in monkeys, these connections define a hierarchical organization of areas in rat visual cortex.
KW - Hierarchical processing
KW - Rat
KW - Reciprocal connections
KW - Sensory cortex
UR - http://www.scopus.com/inward/record.url?scp=0025238442&partnerID=8YFLogxK
U2 - 10.1007/BF00228846
DO - 10.1007/BF00228846
M3 - Article
C2 - 2358036
AN - SCOPUS:0025238442
SN - 0014-4819
VL - 80
SP - 49
EP - 53
JO - Experimental Brain Research
JF - Experimental Brain Research
IS - 1
ER -