Nerve cell loss in the thalamic mediodorsal nucleus in Huntington's disease

We estimated the total neurone number, glial number, and glial index (ratio glial cells/neurone) in the thalamic mediodorsal nucleus (MD) in seven pat ients suffering from Huntington's disease (HD; four males, three females, m ean age 52.4 +/- 13.6 years) and age- and sex-matched controls (four males, three females, mean age 53.6 +/- 12.1 years) by means of a stereological p rotocol. The mean total neurone number (N-(T) over bar) in the MD of contro ls was 2,985,188 +/- 174,710, the mean glial number (G-T; astrocytes, oligo dendrocytes) 21,785,008 +/- 2,986,678, and the glial index 7.29 +/- 0.88. I n HD, the average neurone number was decreased by 23.8% to 2,275,321 +/- 24 7,162 (Mann-Whitney U-test P < 0.05), the mean glial number by 29.7 % to 15 ,318,895 +/- 1,722,524 (Mann-Whitney U-test P < 0.05), the glial index was slightly reduced to 6.81 +/- 1.06. Gallyas' impregnation for the demonstrat ion of fibrous astroglia gave strongly positive results in all cases with H D and negative results in the controls. The morpho-functional correlation o f the results is complicated because individual variability, presence of se gregated and parallel neuronal circuits, and plasticity of the adult human CNS must be considered.