April Flowers for redOrbit.com – Your Universe Online
A growing body of research from Michigan State University reveals that the region of the brain that makes humans and primates social creatures may play a similar role in carnivores. Sharleen Sakai, professor of neuroscience, has studied spotted hyenas, lions, and most recently the raccoon family to find a correlation between the size of the animals’ frontal cortex and their social nature.
The current study, published in the journal Brain, Behavior and Evolution, examined the digitally recreated brains of three species in the Procyonid family – the raccoon, the coatimundi and the kinkajou. The researchers found that the coatimundi had the largest frontal cortex of the three. This bears out the belief that the frontal cortex regulates social interaction, as the coatimundi is by far the most social of the three animals, often living in bands of 20 or more.
“Most neuroscience research that looks at how brains evolve has focused primarily on primates, so nobody really knows what the frontal cortex in a carnivore does,” said Sakai, professor of psychology. “These findings suggest the frontal cortex is processing social information in carnivores perhaps similar to what we’ve seen in monkeys and humans.”
Sakai, part of the MSU faculty member group who helps to make the university’s brain research portfolio one of the most diverse in the nation, collaborated with Bradley Arsznov, a former MSU doctoral student who’s now an assistant professor of psychology at Minnesota State University.
The current study was based on data collected from 45 adult Procyonid skulls acquired from university museum collections – 17 coatimundis, 14 raccoons and 14 kinkajous. Using computed tomography (CT scans) and sophisticated software, the researchers filled in the areas where the brain would have been.
Analyzing the findings allowed the researchers to discover that the female coatimundi had the largest anterior cerebrum volume consisting mainly of the frontal cortex, which regulates social activity in primates. Sakai said that this makes sense, as the female coatimundi is highly social. The male coatimundi, in contrast, once grown, typically lives on its own or with another male. Coatimundi, also known as the Brazilian aardvark, are native to Central and South America.
The smallest frontal cortex was found in raccoons, which are the most solitary of the three animals. The raccoon also has the largest posterior cerebrum – the area of the brain that contains the sensory area related to forepaw sensation and dexterity. Raccoons are known for their extremely dexterous and sensitive forepaws.
The largest cerebellum and brain stem were found in the rainforest-dwelling kinkajou. This region of the brain regulates motor coordination and is crucial for arboreal animals like the kinkajou.
Sakai said that brain size variations in this small family of carnivores appear to be related to behavioral differences, including social interaction.