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The pretectal nuclei in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus).
Brain Struct Funct. 2007 Dec; 212(3-4):359-69.BS

Abstract

We have examined the organization of the pretectal area in two monotremes (the short beaked echidna-Tachyglossus aculeatus, and the platypus-Ornithorhynchus anatinus) and compared it to that in the Wistar strain rat, using Nissl staining in conjunction with enzyme histochemistry (acetylcholinesterase and NADPH diaphorase) and immunohistochemistry for parvalbumin, calbindin, calretinin and non-phosphorylated neurofilament protein (SMI-32 antibody). We were able to identify distinct anterior, medial, posterior (now called tectal gray) and olivary pretectal nuclei as well as a nucleus of the optic tract, all with largely similar topographical and chemoarchitectonic features to the homologous regions in therian mammals. The positions of these pretectal nuclei correspond to the distributions of retinofugal terminals identified by other authors. The overall size of the pretectum in both monotremes was found to be at least comparable in size, if not larger than, the pretectum of representative therian mammals of similar brain and body size. Our findings suggest that the pretectum of these two monotreme species is comparable in both size and organization to that of eutherian mammals, and is more than just an undifferentiated area pretectalis. The presence of a differentiated pretectum with similar chemoarchitecture to therians in both living monotremes lends support to the idea that the stem mammal for both prototherian and therian lineages also had a differentiated pretectum. This in turn indicates that a differentiated pretectum appeared at least 125 million years ago in the mammalian lineage and that the stem mammal for proto- and eutherian lineages probably had similar pretectal nuclei to those identified in its descendants.

Authors+Show Affiliations

Department of Anatomy, School of Medical Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia. k.ashwell@unsw.edu.auNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17717686

Citation

Ashwell, K W S., and G Paxinos. "The Pretectal Nuclei in Two Monotremes: the Short-beaked Echidna (Tachyglossus Aculeatus) and the Platypus (Ornithorhynchus Anatinus)." Brain Structure & Function, vol. 212, no. 3-4, 2007, pp. 359-69.
Ashwell KW, Paxinos G. The pretectal nuclei in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). Brain Struct Funct. 2007;212(3-4):359-69.
Ashwell, K. W., & Paxinos, G. (2007). The pretectal nuclei in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). Brain Structure & Function, 212(3-4), 359-69.
Ashwell KW, Paxinos G. The Pretectal Nuclei in Two Monotremes: the Short-beaked Echidna (Tachyglossus Aculeatus) and the Platypus (Ornithorhynchus Anatinus). Brain Struct Funct. 2007;212(3-4):359-69. PubMed PMID: 17717686.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The pretectal nuclei in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). AU - Ashwell,K W S, AU - Paxinos,G, Y1 - 2007/07/28/ PY - 2007/05/03/received PY - 2007/07/16/accepted PY - 2007/8/25/pubmed PY - 2008/3/1/medline PY - 2007/8/25/entrez SP - 359 EP - 69 JF - Brain structure & function JO - Brain Struct Funct VL - 212 IS - 3-4 N2 - We have examined the organization of the pretectal area in two monotremes (the short beaked echidna-Tachyglossus aculeatus, and the platypus-Ornithorhynchus anatinus) and compared it to that in the Wistar strain rat, using Nissl staining in conjunction with enzyme histochemistry (acetylcholinesterase and NADPH diaphorase) and immunohistochemistry for parvalbumin, calbindin, calretinin and non-phosphorylated neurofilament protein (SMI-32 antibody). We were able to identify distinct anterior, medial, posterior (now called tectal gray) and olivary pretectal nuclei as well as a nucleus of the optic tract, all with largely similar topographical and chemoarchitectonic features to the homologous regions in therian mammals. The positions of these pretectal nuclei correspond to the distributions of retinofugal terminals identified by other authors. The overall size of the pretectum in both monotremes was found to be at least comparable in size, if not larger than, the pretectum of representative therian mammals of similar brain and body size. Our findings suggest that the pretectum of these two monotreme species is comparable in both size and organization to that of eutherian mammals, and is more than just an undifferentiated area pretectalis. The presence of a differentiated pretectum with similar chemoarchitecture to therians in both living monotremes lends support to the idea that the stem mammal for both prototherian and therian lineages also had a differentiated pretectum. This in turn indicates that a differentiated pretectum appeared at least 125 million years ago in the mammalian lineage and that the stem mammal for proto- and eutherian lineages probably had similar pretectal nuclei to those identified in its descendants. SN - 1863-2653 UR - https://www.unboundmedicine.com/medline/citation/17717686/The_pretectal_nuclei_in_two_monotremes:_the_short_beaked_echidna__Tachyglossus_aculeatus__and_the_platypus__Ornithorhynchus_anatinus__ L2 - https://dx.doi.org/10.1007/s00429-007-0155-z DB - PRIME DP - Unbound Medicine ER -