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Time of origin of cortico‐collicular projection neurons in the rat visual cortex
Author(s) -
Contamina P.,
Boada E.
Publication year - 1992
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.903230409
Subject(s) - superior colliculus , biology , visual cortex , horseradish peroxidase , anatomy , neuroscience , striate cortex , population , cortex (anatomy) , axoplasmic transport , midbrain , central nervous system , medicine , biochemistry , environmental health , enzyme
The time of origin and the radial gradient of neurogenesis of cortico‐collicular neurons have been studied in the rat visual area 17. We used a combined technique for the histochemical detection of the retrogradely transported horseradish peroxidase from the superior colliculus and the autoradiographic detection of the [ 3 H]‐thymidine administered during the gestational period. The cortico‐collicular neurons of visual area 17 are located in layer V and are generated on gestational day (GD) 15 (59.78%), GD 16 (36.21%), and GD 17 (4.01%). This finding reveals that, for the cortico‐collicular neuronal population, the birth date is well‐correlated with the laminar position in the adult animal. To see whether the cortico‐collicular neurons located at various radial levels of layer V are generated concurrently, or whether they follow an “insideout” pattern of positioning, we divided layer V into three (upper, middle and lower) sublaminae. Most cortico‐collicular neurons located in the lower two‐thirds of layer V are generated on GD 15 (65%), whereas the neurons located in the upper third of the layer are generated both on GD 15 and GD 16 in almost equal proportions (52.53% and 44.39%, respectively). © 1992 Wiley‐Liss, Inc.