History is being made at George Washington University’s Laboratory for Evolutionary Neuroanatomy, and Stereo Investigator is playing a part. Using Stereo Investigator to count neurons, estimate axon fiber length, and quantify cellular volumes, Dr. Chet C. Sherwood and his team are carrying out “detailed comparisons of neural phenotypes between humans and our closest relatives, the great apes.”
A recent focus at the lab is the emergence and evolution of the human language. In their paper “Wernicke’s area homologue in chimpanzees (Pan troglodytes) and its relation to the appearance of modern human language” (Proceedings of the Royal Society B: Biological Sciences), the authors concluded that the function of Wernicke’s area, a part of the brain linked to speech, and its location in the brain’s left hemisphere “evolved long before the emergence of modern human language.”
Using design based stereological methods, the researchers examined area Tpt in the Wernicke’s area of 12 chimpanzee brains. They used Stereo Investigator to manually draw area Tpt’s boundaries with a Zeiss Axioplan 2 microscope, and found that the number of neurons was greatest on the left side. These findings led them to determine that the positioning of Wernicke’s area originated before humans, chimpanzees, and bonobos evolved from their last common ancestor.
“Stereo Investigator is one of our most important tools,” said Dr. Sherwood. “The software is both intuitive and powerful.”
Read the abstract (free) and full article (by subscription) at royalsocietypublishing.org.
Muhammad A. Spocter, William D. Hopkins, Amy R. Garrison, Amy L. Bauernfeind, Cheryl D. Stimpson, Patrick R. Hof, and Chet C. Sherwood, “Wernicke’s area homologue in chimpanzees (Pan troglodytes) and its relation to the appearance of modern human language” Proceedings of the Royal Society B: Biological Sciences, 2010, doi: 10.1098/rspb.2010.0011