A Comparison of the Cortical Structure of the Bowhead Whale (Balaena mysticetus), a Basal Mysticete, with Other Cetaceans.

Title

A Comparison of the Cortical Structure of the Bowhead Whale (Balaena mysticetus), a Basal Mysticete, with Other Cetaceans.

Creator

Raghanti Mary Ann; Wicinski Bridget; Meierovich Rachel; Warda Tahia; Dickstein Dara L; Reidenberg Joy S; Tang Cheuk Y; George John C; Hans Thewissen J G M; Butti Camilla; Hof Patrick R

Publisher

Anatomical record (Hoboken, N.J. : 2007)

Date

2018
2018-10

Description

Few studies exist of the bowhead whale brain and virtually nothing is known about its cortical cytoarchitecture or how it compares to other cetaceans. Bowhead whales are one of the least encephalized cetaceans and occupy a basal phylogenetic position among mysticetes. Therefore, the bowhead whale is an important specimen for understanding the evolutionary specializations of cetacean brains. Here, we present an overview of the structure and cytoarchitecture of the bowhead whale cerebral cortex gleaned from Nissl-stained sections and magnetic resonance imaging (MRI) in comparison with other mysticetes and odontocetes. In general, the cytoarchitecture of cetacean cortex is consistent in displaying a thin cortex, a thick, prominent layer I, and absence of a granular layer IV. Cell density, composition, and width of layers III, V, and VI vary among cortical regions, and cetacean cortex is cell-sparse relative to that of terrestrial mammals. Notably, all regions of the bowhead cortex possess high numbers of von Economo neurons and fork neurons, with the highest numbers observed at the apex of gyri. The bowhead whale is also distinctive in having a significantly reduced hippocampus that occupies a space below the corpus callosum within the lateral ventricle. Consistent with other balaenids, bowhead whales possess what appears to be a blunted temporal lobe, which is in contrast to the expansive temporal lobes that characterize most odontocetes. The present report demonstrates that many morphological and cytoarchitectural characteristics are conserved among cetaceans, while other features, such as a reduced temporal lobe, may characterize balaenids among mysticetes. Anat Rec, 2018. (c) 2018 Wiley Periodicals, Inc.

Subject

baleen whale; cytoarchitecture; humpback whale; minke whale; sperm whale

Identifier

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Citation

Raghanti Mary Ann; Wicinski Bridget; Meierovich Rachel; Warda Tahia; Dickstein Dara L; Reidenberg Joy S; Tang Cheuk Y; George John C; Hans Thewissen J G M; Butti Camilla; Hof Patrick R, “A Comparison of the Cortical Structure of the Bowhead Whale (Balaena mysticetus), a Basal Mysticete, with Other Cetaceans.,” NEOMED Bibliography Database, accessed April 14, 2021, https://neomed.omeka.net/items/show/2974.

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