How did you spend your day at work? We’re betting that it wasn’t quite as noteworthy as a recent day enjoyed in the labs at Germany’s Ruhr-University Bochum (RUB), where researchers set out to explore the neurobiology of one of the natural world’s largest, toothiest reptiles. Their methodology: Scan a live crocodile’s brain in an fMRI machine while playing it the classical music of Johann Sebastian Bach. And, presumably, try not to lose a limb in the process.
“Crocodiles count among the most ancient species of vertebrates and have barely changed over the space of more than 200 million years,” Mehdi Behroozi, a researcher on the project, told Digital Trends. “Accordingly, they constitute a link between dinosaurs and bird species today. Analyses of crocodile brains thus provide deep insights into the evolution of the nervous system in mammals and may help us understand at which point certain brain structures and behaviors associated therewith were formed.”
The Nile crocodile was borrowed from a local zoo each day of the experiment. Transferred to an animal scanning center, it was mildly sedated and then fixed in a restraining apparatus for the duration of scanning. This involved adjusting the scanner in order to more effectively dial in on the cold-blooded reptile’s brain activity.
The goal of the experiment was to search for differences in brain activation when the crocodile was played sounds of differing complexity. A tone at a fixed frequency range served as a simple stimulus, while an excerpt from Bach’s Brandenburg Concerto No. 4 acted as a complex stimulus, due to its broad spectrum of frequencies and fast amplitude changes. The findings confirmed that, at least when it comes to appreciating the classics, crocs and birds aren’t all that far apart.
“We were baffled when we saw how similar the crocodile brain activity was in comparison to birds when we played classical music to them,” Behrooz continued. “Sure, given the fact that birds produce quite sophisticated ‘music’ on their own, one can assume that they have specialized brain areas to process complex sounds. But we did not expect that crocodiles have areas which look and seem to work so similar. Our study shows that fMRI can be used to investigate neural processing in poikilotherms, providing a new avenue for neurobiological research in these critical species — for example, vocalization mechanism.”
Now if only we knew a bit more about the music tastes of the crocodiles’ dino-ancestors. We’re guessing they would opt for John Williams’ Jurassic Park suite!
A paper describing the research was recently published in the Proceedings of the Royal Society B: Biological Sciences journal.