8. Comparative Stereology Studies of Brains from Marine Mammals

  1. Peter R. Mouton PhD
  1. Nina Eriksen and
  2. Bente Pakkenberg

Published Online: 22 NOV 2013

DOI: 10.1002/9781118444177.ch8

Neurostereology: Unbiased Stereology of Neural Systems

Neurostereology: Unbiased Stereology of Neural Systems

How to Cite

Eriksen, N. and Pakkenberg, B. (2014) Comparative Stereology Studies of Brains from Marine Mammals, in Neurostereology: Unbiased Stereology of Neural Systems (ed P. R. Mouton), John Wiley & Sons, Inc., Ames, USA. doi: 10.1002/9781118444177.ch8

Author Information

  1. Research Laboratory for Stereology and Neuroscience, Bispebjerg Hospital, University Hospital of Copenhagen, Copenhagen, Denmark

Publication History

  1. Published Online: 22 NOV 2013
  2. Published Print: 17 JAN 2014

ISBN Information

Print ISBN: 9781118444214

Online ISBN: 9781118444177

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Keywords:

  • brains;
  • cerebellum;
  • cetacean brain;
  • glial cells;
  • marine mammals;
  • neocortical neurons;
  • pinniped brain;
  • sirenian brain;
  • stereology

Summary

The brains of cetaceans differ in numerous ways from terrestrial mammals and pinnipeds, showing a higher degree of gyrification. Despite the fact that pinnipeds are semiaquatic, the cytoarchitectural organization of the pinniped brain resembles that of terrestrial carnivores though larger than their terrestrial relatives. The sirenian brain is unusually small for the animals′ size, and structurally simpler than other marine mammals. Most marine mammals have a well-developed cerebellum. This chapter illustrates the estimation of total neocortical neurons and glial cells in different marine mammals. There are both stereological and nonstereological estimates. Adaptation to marine life requires three-dimensional locomotion and deep diving, which results in four major adaptations in the marine mammal brain: (1) increased brain size due to enlarged special functional areas for the auditory and motor systems, (2) increased neocortical volume, (3) increased neocortical surface and gyrification, and (4) strong reduction or loss of the olfactory system.