Divergent social functioning in behavioral variant frontotemporal dementia and Alzheimer disease: reciprocal networks and neuronal evolution.

Behavioral variant frontotemporal dementia (bvFTD) disrupts our most human social and emotional functions. Early in the disease, patients show focal anterior cingulate cortex (ACC) and orbital frontoinsula (FI) degeneration, accentuated in the right hemisphere. The ACC and FI, though sometimes considered ancient in phylogeny, feature a large bipolar projection neuron, the von Economo neuron (VEN), which is found only in humans, apes, and selected whales-all large-brained mammals with complex social structures.

Early frontotemporal dementia targets neurons unique to apes and humans.

Objective: Frontotemporal dementia (FTD) is a neurodegenerative disease that erodes uniquely human aspects of social behavior and emotion. The illness features a characteristic pattern of early injury to anterior cingulate and frontoinsular cortex. These regions, though often considered ancient in phylogeny, are the exclusive homes to the von Economo neuron (VEN), a large bipolar projection neuron found only in great apes and humans.