A stereological study of the mediodorsal thalamic nucleus in Down syndrome

Topic: Brain proteins, microglia and lab models

The total number of neurons and glial cells in the mediodorsal thalamic (MDT) nucleus of four aged females with Down syndrome (DS; mean age 69years) was estimated and compared to six age- and sex-matched controls. The MDT nucleus was delineated on coronal sections, and cell numbers (large and small neurons, oligodendrocytes, and astrocytes) were estimated using the optical fractionator technique. The DS brains had an average of 3.41×10(6) total neurons in the MDT nucleus in contrast to 5.97×10(6) in the controls, with no overlap (2p=0.004), affecting large (projecting) and small (local inhibitory) neurons nearly equally. In contrast, we observed no significant differences in either glial cell population. The cortical structures of the same four DS brains were previously estimated to be half the normal size of controls with a reduction in cell numbers whereas the basal ganglia were unaffected. As DS brains are affected by developmental delay, premature aging, and Alzheimer-like pathology, the finite cause of the reduced number of cells in MDT nucleus cannot be determined; however, these findings provide stereological evidence for a local reduction in neuron numbers in the MDT nucleus, which could affect the cognitive capacity of patients with DS.

Key findings

• The total number of neurons and glial cells in the mediodorsal thalamic (MDT) nucleus of four aged females with Down syndrome (DS; mean age 69years) was estimated and compared to six age- and sex-matched controls.
• In contrast, we observed no significant differences in either glial cell population.
• As DS brains are affected by developmental delay, premature aging, and Alzheimer-like pathology, the finite cause of the reduced number of cells in MDT nucleus cannot be determined; however, these findings provide stereological evidence for a local reduction in neuron numbers in the MDT nucleus, which could affect the cognitive capacity of patients with DS.

Why it matters

In four aged females with Down syndrome, the mediodorsal thalamic nucleus had an average of 3.41 million neurons compared with 5.97 million in controls, with no significant differences in glial cell populations. The authors state the cause of the reduced neuron numbers cannot be determined, and the study does not test any treatment or cure.

Study details

• Evidence strengthLow

Read the original

• DOI: 10.1016/j.neuroscience.2014.08.046
• PubMed: 25220902
• Original source →

May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.

@article{karlsen2014-25220902,
  author  = {Karlsen, A. S. and Korbo, S. and Uylings, H. B. and Pakkenberg, B.},
  title   = {{A stereological study of the mediodorsal thalamic nucleus in Down syndrome}},
  journal = {Neuroscience},
  year    = {2014},
  doi     = {10.1016/j.neuroscience.2014.08.046},
  pmid    = {25220902},
  url     = {https://doi.org/10.1016/j.neuroscience.2014.08.046}
}

Studies this one cites

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• Cognitive deficits and associated neurological complications in individuals with Down's syndrome The Lancet. Neurology · 2010-06-01 · usefulness score 53/100 · Getting a diagnosis
• Down syndrome phenotypes: the consequences of chromosomal imbalance Proceedings of the National Academy of Sciences of the United States of America · 1994-05-01 · usefulness score 52/100 · Down syndrome and Alzheimer's
• Behavioral phenotype of individuals with Down syndrome Mental retardation and developmental disabilities research reviews · 2000-01-01 · usefulness score 43/100 · Digital health tools
• Total numbers of neurons and glial cells in cortex and basal ganglia of aged brains with Down syndrome--a stereological study Cerebral cortex (New York, N.Y. : 1991) · 2011-03-22 · usefulness score 41/100 · Down syndrome and Alzheimer's

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