Vertebrates share ancient neural circuitry for complex social behaviors: study

May 31, 2012

Humans, fish and frogs share neural circuits responsible for a diversity of social behavior, from flashy mating displays to aggression and monogamy, that have existed for more than 450 million years, biologists at The University of Texas at Austin found.

"There is an ancient circuitry that appears to be involved in social behavior across all vertebrates," said Hans Hofmann, associate professor of . "On a basic level, this tells us something about where we came from. A lot of the that our brain uses for social behavior are actually quite old."

Hofmann and graduate student Lauren O'Connell published their research in this week's Science.

The biologists analyzed 12 regions of the brain responsible for social behavior and decision-making in 88 species of vertebrates including birds, mammals, reptiles, amphibians and fish.

They specifically looked at gene activity in two neural networks, one responsible for evaluating the relative importance of stimuli (the mesolimbic reward system), and one responsible for social behavior (the network). The former is important in and romantic love, which manifests in the brain surprisingly like drug addiction.

"In these key , we found remarkable conservation of gene activity across species," said Hofmann.

Despite the discovery of such consistency in gene activity, it's easy to see that vertebrates have evolved a large diversity of behaviors during the past 450 million years.

That diversity can be partly explained, said Hofmann, as small variations on a theme. The basic neural circuits evolved long ago, providing a genetic and molecular framework for the evolution of new behavior. Small tweaks over time in those neural circuits then give rise to new behavior.

Monogamy, for example, has evolved multiple times independently in various . Monogamous behavior can be more advantageous for reproduction and survival under certain environmental conditions, and the research suggests that the evolution of this behavior is probably the result of small tweaks in a conserved neural network rather than evolving an entirely new one.

"Vertebrate brains are incredibly diverse, but we are finding the commonalities, even at the level of ," said Hofmann. "Now we have a framework with which we can ask whether there are molecular universals associated with social behaviors."

Hofmann described "molecular universals" as common genes and molecules shared across species that form the bases of behavior, and he is on the hunt for them. This research highlights the areas of the vertebrate brain where he can now look for molecular universals in these shared neural circuits.

Explore further: Molecular gate that could keep cancer cells locked up

More information: "Evolution of a Vertebrate Social Decision-Making Network," by L.A. O’Connell; Science, 2012.

Related Stories

Is that song sexy or just so-so?

Sep 22, 2008

Why is your mate's rendition of Marvin Gaye's "Let's Get it On" cute and sexy sometimes and so annoying at other times? A songbird study conducted by Emory University sheds new light on this question, showing that a change ...

Chimp, bonobo study sheds light on the social brain

Apr 05, 2011

It's been a puzzle why our two closest living primate relatives, chimpanzees and bonobos, have widely different social traits, despite belonging to the same genus. Now, a comparative analysis of their brains shows neuroanatomical ...

Aggression-boldness gene identified in model fish

Oct 05, 2011

A gene responsible for aggressive and bold behavior has been identified in zebrafish by a French team from CNRS/Laboratoire Neurobiologie et Développement. This specific behavioral association, whose ...

Research defines neurons that control sociability in worms

Apr 10, 2009

(PhysOrg.com) -- Ants colonize. Fish shoal. Flamingos flock and caribou herd. Earth is populated by inherently social beings. Even lowly worms seek out the benefits of companionship. New research at The Rockefeller ...

Recommended for you

Molecular gate that could keep cancer cells locked up

2 hours ago

In a study published today in Genes & Development, Dr Christian Speck from the MRC Clinical Sciences Centre's DNA Replication group, in collaboration with Brookhaven National Laboratory (BNL), New York, ...

The 'memory' of starvation is in your genes

6 hours ago

During the winter of 1944, the Nazis blocked food supplies to the western Netherlands, creating a period of widespread famine and devastation. The impact of starvation on expectant mothers produced one of the first known ...

User comments : 0