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Pretectal connections in turtles with special reference to the visual thalamic centers: A hodological and γ‐aminobutyric acid‐immunohistochemical study
Author(s) -
Kenigfest Natalia B.,
Belekhova Margarita G.,
Repérant Jacques,
Rio Jean Paul,
Vesselkin Nicolas P.,
Ward Roger
Publication year - 2000
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 - 10.1002/1096-9861(20001009)426:1<31::aid-cne3>3.0.co;2-s
Subject(s) - pretectal area , biology , nucleus , neuroscience , midbrain , anatomy , forebrain , tegmentum , oculomotor nucleus , visual system , tectum , thalamus , retrograde tracing , central nervous system , visual cortex
Projections of the pretectal region to forebrain and midbrain structures were examined in two species of turtles ( Testudo horsfieldi and Emys orbicularis ) by axonal tracing and immunocytochemical methods. Two ascending γ‐aminobutyric acid (GABA)ergic pathways to thalamic visual centers were revealed: a weak projection from the retinorecipient nucleus lentiformis mesencephali to the ipsilateral nucleus geniculatus lateralis pars dorsalis and a considerably stronger projection from the nonretinorecipient nucleus pretectalis ventralis to the nucleus rotundus. The latter is primarily ipsilateral, with a weak contralateral component. The interstitial nucleus of the tectothalamic tract is also involved in reciprocal projections of the pretectum and nucleus rotundus. In addition, the pretectal nuclei project reciprocally to the optic tectum and possibly to the telencephalic isocortical homologues. Comparison of these findings with previous work on other species reveals striking similarities between the pretectorotundal pathway in turtles and birds and in the pretectogeniculate pathway in turtles, birds, and mammals. J. Comp. Neurol. 426:31–50, 2000. © 2000 Wiley‐Liss, Inc.