Open in iTunes  |   Subscribe via RSS

 

September 10, 2008

Similar brains, different behaviors

Download the audio file

[Transcript]

ATLANTA — One is as orange as a traffic cone and bends its mouth to its tail to flee predators in the ocean. The other is transparent, has its eyes attached right to its brain and moves from side to side in the earth’s seas.

These two other-worldly looking sea slugs are helping scientists to explore why animals with similar brains, including humans and other primates, behave differently.

Paul Katz, director of Georgia State’s Center for Neuromics, has explored the brains of Tritonia and Melibe sea slugs to see how similar brain cells called neurons work. Researchers think that over time, similar — or homologous — neurons evolved to work differently and create different behaviors.

KATZ: It doesn't take new parts of the brain to evolve new behaviors. The evolution of nervous systems basically comes down to repartitioning, reassigning functions, but not generating new brain areas, or new types of things, generally. (length: 0:18)

He and a former student, James Newcomb, found that one key difference between the two species was that a neurotransmitter called serotonin was needed in the Tritonia for it to swim, but the Melibe didn’t.

KATZ: Serotonin is not necessary for swimming in Melibe, but it is necessary for swimming in Tritonia. That's a fundamental difference, and that arises out of the circuitry, because the cells are part of the circuit in Tritonia, and they're not part of the circuit in Melibe. So even though they're the same cells, somehow they've been used differently in the neural circuitry in these two animals. (length: 0:20)

In the end, Katz’s research speaks to a philosophical question which Georgia State’s multidisciplinary Neuroscience Institute seeks to answer.

KATZ: It talks about the concept of how neural circuits potentially have evolved. So that is of general interest to understanding one of the fundamental questions of why we are the way we are. (length: 0:16)

For Georgia State RadioLine, this is Jeremy Craig.