Quantification of interneurons present in postmortem adult Down syndrome Brain
Neuroanatomical abnormalities in the DS brain contribute to specific cognitive deficits in DS individuals. Histopathology has consistently revealed fewer neurons in the DS cerebral cortex. Based on neuron morphology and the developmental timing of the neuron reductions, the missing neurons may be interneuron. We sought to resolve the identity of the neuron subtype that is affected so as to both increase our knowledge of DS neuropathology and our ability to define potential therapies. We identified neurons using immunocytochemistry in post-mortem human brain cerebral cortex, specifically the superior temporal gyros, and quantified by design-based stereology. Our results reveal a reduction in neuron density in DS STG compared to control, corroborating previous histopathology that reported up to a 50% reduction in the number of neurons in DS cortex. Importantly, comparison of interneuron subtypes (PV, CR) indicate that there is a similar reduction in density of these subtypes in DS STG suggesting that there is a general reduction of interneuron in DS cortex.