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In the Light of Evolution Volume VI: Brain and Behavior (2013) / Chapter Skim
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Part II: DEVELOPMENTAL AND ADULT VARIATION IN NEURAL ORGANIZATION
Pages 57-60

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 57...
... They note that hox genes also control segmental variation in the motor neurons that control the various appendages. This observation is important because it suggests that variation in hox gene expression patterns can coordinate evolutionary changes in appendage morphology with evolutionary changes in motor neurons, thus ensuring functionality.
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From page 58...
... These findings suggest that cortical modules are generated by Hebbian plasticity, which strengthens connections between neurons that fire simultaneously or nearly simultaneously. Although this form of plasticity is most often invoked as a mechanism for generating topographic maps within the brain, it can also explain the formation of abrupt boundaries, because such boundaries can maximize the overall probability that adjacent neurons fire concordantly.
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From page 59...
... Using the isotropic fractionator method, which involves homogenizing brain regions and counting stained cell nuclei in samples from the resulting homogenate, she discovered that neuron numbers scale differently (against brain region mass) in primates and rodents.
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Key Terms

  • evolutionary changes
  • motor neurons
  • hox genes
  • brain size
  • pia mater

  • adjacent neurons
  • increases tectum
  • neurons tend
  • primate scaling
  • blind mole

  • kaas suggests
  • neural expansion
  • various appendages
  • strengthens connections
  • hebbian plasticity

  • brain mass
  • hox gene
  • seelke focus
  • counting stained
  • mammalian taxa

  • segmental variation
  • similar cascade
  • overall probability
  • exist throughout
  • erin jarvis

  • induce changes
  • kaas continues
  • tectum size
  • control segmental
  • related brain


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