Belgian researchers have compared human and primate brain activity by showing Clint Eastwood's epic spaghetti western film, 'The Good, the Bad and the Ugly' to members of both species. As expected, their findings uncovered many similarities in brain function, but also some surprising differences.
LEUVEN, BELGIUM (RECENT) (UNIVERSITY OF LEUVEN) -When Hollywood actor Clint Eastwood starred in the classic spaghetti western 'The Good, the Bad, and the Ugly' in 1966 it's unlikely he envisaged his lead role being one day used to help scientists investigate brain evolution.
Yet almost half a century later the epic movie has been adapted for that very purpose, with reseacrhers using it to help compare the brain regions of monkeys and humans.
A team of American and Italian neuroscientists at Belgium's Catholic University of Leuven (KUL) monitored how four Rhesus monkeys and 24 humans responded to watching a 30-minute clip of the film.
Their goal was to analyse how both primates' brains responded to the same stimulus and whether or not the activity occurred in the same regions of the brain. The team's hypothesis was that watching the same features of the film should activate similar responses in both species.
The movie was selected because it had previously been used by a separate group of Italian researchers studying brain activity in humans and incorporated this research.
Each participant was placed inside a magnetic resonance imaging (MRI) scanner, where they watched the popular Hollywood film, listening to the dialogue by wearing headphones. Human participants viewed the clip once, while the monkeys watched it six times.
For the most part the team's results ultimately confirmed their hypothesis that the brain is similar in the two species, according to lead researcher Wim Vanduffel, from Harvard University.
"When there was some hand action going on, an actor grasping an object, grasping a gun or something like that, both monkeys and humans look at this kind of action," said Vanduffel.
"I was also surprised, this might be a coincidence, but when there was sort of like a gun in a particular scene, both monkeys and humans looked at that particular gun. But honestly, we still have to do much more detailed analysis and sort of ongoing research about what specifically is driving attention of both species and what are they really looking at during the movie sequence."
The research team's method, called "inter-species activity correlation", first compared brain activity in areas that are known to correlate between the species before they tried the same experiment by monitoring other areas of the brain.
The scientists' findings showed that brain regions that do the same job in monkeys and humans aren't always found in the same part of the skull. Previous studies comparing brains across species tended to assume that human brains were just larger versions of monkey brains and that functions are carried out by anatomically similar areas.
"We did find some surprising small details where the human brain and the monkey brain seems to differ quite a bit and of course this opens up new possibilities to investigate what's going on there in more detail," said Vanduffel. "I'm very much looking forward actually, we are analysing other data as well where we get like clues of areas or networks of areas which seem to be human specific so where there's no counterpart at all in non-human primates or at least the primates we've been testing."
Vanduffel says their research is unique because only a handful of labs around the world have the tools needed to conduct these experiments.
The collection of data from the monkeys and humans was completed in 2009 and has been analysed over the past three years.
Nature Methods, a peer-reviewed scientific and medical journal, published their study in February this year.
Vanduffel said his team is now looking into examining whether the human brain houses human-specific functions, such as cognitive and motor capabilities.
They are also working on a new facial recognition study, again using Rhesus monkeys. The results of this study will allow the research team to identify the areas in the brain that are responsible for the recognition of faces.