A little Bach for your croc?

Researchers using MR scans to test the impact of complex sounds on the brains of crocodiles have found they have a taste for classical music.

They said that it is the first such scan of a reptile and opens the way for similar studies in many other species that have not yet been so examined.

International researchers led by Dr. Felix Ströckens from the Department of Biopsychology at Ruhr-Universität Bochum (RUB) examined the cold-blooded reptile with functional MR.

Scans revealed that the stimuli set off activation patterns in the animal's brain “similar to those in birds and mammals,” they reported in the journal Proceedings of the Royal Society B: Biological Sciences.

"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," explained Ströckens.

Setting up the scanner for the coldblooded creatures proved technically challenging for the team, which included investigators from Iran, South Africa, France, and Germany.

"For example, we had to adjust the scanner to the crocodile's physiology, which differs massively from that of mammals in several aspects," said research team member Mehdi Behroozi.

The animals were then exposed to a variety of stimuli, including music by Johann Sebastian Bach, during which time their brain activity was assessed.

The results showed that additional brain areas were triggered from the classical music versus simple sounds, resulting in patterns that were similar to those produced in mammals and birds.

The implication is that “fundamental neuronal processing mechanisms of sensory stimuli formed at an early evolutionary stage, and that they can be traced back to the same origins in all vertebrates,” the scientists advised.

This is far from the only example of unusual applications of functional MR in the news.

In 2016, the technology was used to study the minds of pianists while they played music by Malinda McPherson, a Ph.D. student in the Harvard/MIT Program for Speech and Hearing Bioscience and Technology.

McPherson had 12 professional pianists undergo a 24-minute scan while playing a small keyboard. Her research showed that connections between emotions and creativity tend to be more nuanced than previously demonstrated and suggested that even the intention of expressing an emotion — such as sadness — can have a powerful impact on neural activity. "Sadness in music may be pleasurable because we know the sadness is coming from the art, and not real-world tragedy," McPherson told HCB News.

Also in 2016, researchers used fMRI to look at performance anxiety.

Neuroscientists from Sussex’s Sackler Centre and Brighton and Sussex Medical School were able to identify brain regions involved with the disorder, including that the inferior parietal cortex (IPC) and the posterior superior temporal sulculus (pSTS) work together to form what is referred to as the action–observation network (AON) which helps anticipate what another person might be thinking by viewing their facial expressions.

But care needs to be used when analyzing functional MR with common statistics, as it can yield false results, researchers reported in 2016.

Anders Eklund and Hans Knutsson from Linköping University, and Thomas Nichols from the University of Warwick tested the analysis methods on “known, reliable data” and the researchers found that the methods showed false brain activity on 60 percent of images when a reasonable percentage is five.

Eklund suggested that a new method for validating the fMRI information be used that makes fewer assumptions and “a thousand times more” calculations than the conventional method that produces errors.

“Thanks to modern graphics cards, large calculations can be run,” said Eklund in a statement. “It would take 1,000 times longer to run the calculations using a normal computer, but thanks to the graphics cards, I reduced the processing time from 10 years to 20 days.”

The researchers used resting-state fMRI data from 499 healthy controls to conduct 3 million task group analyses. "Using this null data with different experimental designs, we estimate the incidence of significant results. In theory, we should find 5 percent false positives, ... but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70 percent," they wrote in their study.