title: A stereological study of the mediodorsal thalamic nucleus in Down syndrome.
abstract: 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.
authors.affiliation: Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospitals, Bispebjerg Bakke 23, 11B 2, DK-2400 Copenhagen NV, Denmark.
authors.forename: A S
authors.initials: AS
authors.lastname: Karlsen
authors.affiliation: Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospitals, Bispebjerg Bakke 23, 11B 2, DK-2400 Copenhagen NV, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Korbo
authors.affiliation: Department of Anatomy and Neurosciences, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
authors.forename: H B M
authors.initials: HB
authors.lastname: Uylings
authors.affiliation: Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospitals, Bispebjerg Bakke 23, 11B 2, DK-2400 Copenhagen NV, Denmark. Electronic address: bente.pakkenberg@regionh.dk.
authors.forename: B
authors.initials: B
authors.lastname: Pakkenberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002452:Cell Count; D004314:Down Syndrome / Q000473:pathology*; D005260:Female; D006801:Humans; D020645:Mediodorsal Thalamic Nucleus / Q000473:pathology*; D008875:Middle Aged; D009457:Neuroglia / Q000473:pathology; D009474:Neurons / Q000473:pathology*; D009929:Organ Size
keywords: aging; cognition; development; optical fractionator; thalamus; trisomy 21