Scientists wanted to learn how an ancient brain would react to complex audio and visual stimuli. To do this, they had to find one animal with the oldest brain around and strap it into an MRI, all while making sure they don’t get bitten in the process.
A team of German scientists from Ruhr University Bochum used a combination of colored lights and Johann Sebastian Bach’s “Brandenburg Concerto No. 4” to see what part of a crocodile’s brain would light up during an MRI scan in an experiment published in April. What they learned from the experiment was the reptilian brain reacts to the sounds and visuals similar to mammals and birds. The team, led by Felix Ströckens, also learned that putting a cold-blooded animal in an MRI was a challenge they had to resolve since the machine picks up certain brain activity from the temperature of the blood, which is colder in crocs than mammals.
“We thus had to find a temperature which allowed us to pick up a good signal and was comfortable for the animal,” Ströckens told Gizmodo. “We also had to keep this temperature stable within the scanner which is relatively difficult since the coils used for scanning also emit heat.”
Five juvenile Nile crocodiles were sedated with their mouths taped shut for the experiment. The animal has changed little over the past 200 million years, which made them the ideal candidate for the study. The scientists noted that since the crocodile brains have a similar reaction to the stimuli, then that means animal brains evolved much earlier than expected to register these signals, which could mean the reaction started with dinosaur brains. They also learned that the MRI can actually work on cold-blooded animals.
The team published their findings in the Proceedings of the Royal Society B in late April.
In another example of humans not being that much different than animals, a study in February found people can use echolocation similar to bats.