Because the cells arose only recently in evolutionary history -- in a common ancestor of great apes and humans-- and are particularly abundant in humans, and the finding supports the concept that evolution has rendered the human brain vulnerable to disease, including frontotemporal dementia, and, possibly, disorders such as autism and schizophrenia, the researchers say.
In addition, because the disease erodes aspects of social behavior and emotions ?self awareness, moral reasoning and empathy ?that are highly developed in humans, the finding suggests that the cells may play a role in what makes humans "human," they say.
The finding is reported in the December 22 on-line issue of Annals of Neurology.
The cells, known as von Economo neurons, were first comprehensively described in 1925 by their Romanian-Austrian namesake, who determined that the unusually shaped cells -- large, cigar-shaped and tapered at each end, with only a few dendritic processes extending away from them ?were localized in only two regions of the frontal lobes.
The cells received only limited attention in the ensuing years, but in the meantime scientists determined that the brain regions in which von Economo neurons arise -- the anterior cingulate and frontoinsular cortex -- are key targets of frontotemporal dementia. And in 1999, a team of U.S. scientists made the surprising discovery that, among primates, von Economo neurons were seen only in great apes and humans.
In the current study, the UCSF team set out to explore whether von Economo neurons could be the target of FTD.
Working in the laboratory of senior author Stephen J. DeArmond, MD, PhD, UCSF professor of pathology, they compared the numbers
Source:University of California - San Francisco