Quantitative comparison of radial cell columns in children with Down's syndrome and controls

No one has examined the configuration of the minicolumns in Down's syndrome (DS) brains even though these are a basic functional unit of the cortex. In the present study, the authors used computerized imaging to examine minicolumns in the posterior superior temporal gyrus in both the brains of patients with DS and normal controls. They compared the brains of children aged 4 and 6 years with those of adults for both people with DS and the normal population. Columns in the brains of two DS children aged 4 and 6 years were almost the same size as those of the adults with DS. The neuropil space in the periphery of the columns was also considerably wider. In contrast, minicolumns in aged-matched control children were smaller, both relatively and absolutely, when compared to the mean size of adult columns. The size of the minicolumns in the normal children apparently corresponded to the overall brain size, whereas the large columns in children with DS appeared to be independent of brain size, at least in area Tpt. This seems to reflect a rapid ageing process that is striking when compared to normal controls. Columns in adults with DS were large and less cell dense, while brain volumes were significantly smaller than in controls. This combination suggests reduced neuronal complexity based on a decrease in processing units, which supports previous findings of decreased cell numbers and synaptic diminution in DS brains.