RETT-SYNDROME - 3-D CONFOCAL MICROSCOPY OF CORTICAL PYRAMIDAL DENDRITES AND AFFERENTS

AUTOPSY material from three patients with Rett syndrome and six contro l cases (frontal, temporal and motor cortical areas) were studied. Pyr amidal and non-pyramidal neurones, 100-200 in each specimen, were visu alized by Lucifer Yellow microinjection. 3-D reconstructions and rotat ions were computed using the VoxelView/GT program. Various types of ab normalities in 3-D dendritic architecture of pyramidal neurones in dif ferent cortices were observed. Some pyramidal cells in layers II-III h ad a subnormal number of dendrites. The normally occurring specializat ions in pyramidal architecture in different cortical areas were absent . Decreased numbers and regional loss ('naked' areas) of dendritic spi nes were found. Widely distributed cortical afferents were shown by th e carbocyanine dye (DiI) tracing method. PAD showed no microdysgenesis , in contrast to the observations in epilepsy.