Planning a trip? Scans show how your brain plots the route
Magnetic resonance imaging reveals the multitude of brain regions involved in navigation – from the primal to the high-level. Belinda Smith reports.
Do you get frustrated retracing your steps to the car in a multi-level car park or planning which route you'll take to a party? For some, navigation – or even thinking about it – can be a real headache.
Now neuroscientists have imaged the parts of the brain that kick in when we perform these tasks, from primal memory structures to higher level areas that can foresee future plans.
In work published in Science, psychologists in the US led by Stanford University's Thackery Brown watched various brain regions in human subjects lit up as they explored a virtual environment and planned a journey.
They were able to do this with functional magnetic resonance imaging, or fMRI, which measures blood flow in the brain. As an area of the brain becomes active, and its neurons become excited and fire, it needs blood – and it's that flow the fMRI picks up.
Brown and colleagues showed their subjects a virtual environment on a screen and asked them to explore the region and navigate to five points.
The next day, the subjects were asked to find their way to those points again – but this time, they were lying in a fMRI machine.
Even before they "set off" on their virtual journey, the machine scanned their brain to see which parts were involved in planning the route. They saw a region called the orbitofrontal cortex, at the front of the brain, lit up when the participants thought about their end point.
The frontopolar cortex encoded this information and sent it to the hippocampus, which is responsible for memory and learning.
It wasn't a simple relationship between hippocampus and orbitofrontal cortex – other regions fed into the network and helped the brain "visualise" where it was going (the parahippocampal cortex, perirhinal cortex and retrosplenial complex, if you're interested).
So the next time you find yourself wandering around the wrong car park floor or circling the block for the tenth time, cut yourself some slack – your brain is working hard.