TY - JOUR
T1 - Sequential development of connections between striate and extrastriate visual cortical areas in the rat
AU - Coogan, Thomas A.
AU - Burkhalter, Andreas
PY - 1988/12/8
Y1 - 1988/12/8
N2 - In these experiments we have asked whether the projection from the rat's primary visual cortex, area 17, to the extrastriate visual cortical area 18a is formed in a sequence and whether that sequence resembles the pattern of inside‐out cortical neurogenesis. For this purpose fluorescent retrograde tracers were injected into area 18a at different postnatal ages (P1, P5, adult). Animals survived until 3–4 weeks of age, after migration is complete and neurons have arrived at their final laminar location. In the ipsilateral cortex, P1 injections retrogradely labeled cells in layers 5 and 6 of area 17. Labeling after P5 injections extended into more superfical layers and included the bottom of layer 2/3 and layers 4–6. After P5, more labeled cells were found at the top of layer 2/3, producing the adult laminar pattern, where the projection originates predominantly from layer 2/3. A similar sequence of laminar labeling was observed in the transcallosal connection of area 18a. This sequence of labeling, deep layers before superficial, resembles the pattern in which cortical neurons are born and indicates that axons arrive at their cortical targets in the order the cells were generated.
AB - In these experiments we have asked whether the projection from the rat's primary visual cortex, area 17, to the extrastriate visual cortical area 18a is formed in a sequence and whether that sequence resembles the pattern of inside‐out cortical neurogenesis. For this purpose fluorescent retrograde tracers were injected into area 18a at different postnatal ages (P1, P5, adult). Animals survived until 3–4 weeks of age, after migration is complete and neurons have arrived at their final laminar location. In the ipsilateral cortex, P1 injections retrogradely labeled cells in layers 5 and 6 of area 17. Labeling after P5 injections extended into more superfical layers and included the bottom of layer 2/3 and layers 4–6. After P5, more labeled cells were found at the top of layer 2/3, producing the adult laminar pattern, where the projection originates predominantly from layer 2/3. A similar sequence of laminar labeling was observed in the transcallosal connection of area 18a. This sequence of labeling, deep layers before superficial, resembles the pattern in which cortical neurons are born and indicates that axons arrive at their cortical targets in the order the cells were generated.
KW - area 17
KW - area 18a
KW - corpus callosum
KW - development of cortical connections
KW - extrastriate visual cortex
KW - visual cortex
UR - http://www.scopus.com/inward/record.url?scp=0024238633&partnerID=8YFLogxK
U2 - 10.1002/cne.902780207
DO - 10.1002/cne.902780207
M3 - Article
C2 - 3230163
AN - SCOPUS:0024238633
SN - 0021-9967
VL - 278
SP - 242
EP - 252
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
IS - 2
ER -