October 29, 2017, 12:27 pm
Sleepwalkers are known to perform complex movements such as walking in the absence of full consciousness. This ability may translate into a multi-tasking advantage for sleepwalkers when they are awake over non-sleepwalkers, researchers have found.
A new research using virtual reality (VR) has revealed significant differences in how the brains of sleepwalkers and non-sleepwalkers control and perceive body movement.
The results of the study, published in the Journal Current Biology, indicated that sleepwalkers exhibit increased automation in their movements with respect to non-sleepwalkers.
For the study, using a full-body motion capture suit in a room full of IR-tracking cameras sleepwalkers and non-sleepwalkers were asked to walk towards a target object -- a virtual cylinder.
The subject was shown a life-size avatar that could truthfully replicate or deviate from the subject’s actual trajectory in real-time. Participants could, therefore, be tricked into walking along a modified trajectory to compensate for the avatar deviation.
Their walking speed and accuracy of movement along with their movement awareness were then recorded and analysed. There was no difference between sleepwalkers and non-sleepwalkers while performing this first task -- just as previous research would have suggested.
When the researchers added a layer of complexity, however, a clear distinction emerged between the two groups.
Subjects were asked to count backward in steps of seven starting from 200. Non-sleepwalkers significantly slowed down when having to count backward while walking, yet sleepwalkers maintained a similar walking velocity in both conditions, showing a strong link between sleepwalking and automatic control of locomotion not during nocturnal episodes of sleepwalkers, but during full wakefulness.
“We found that sleepwalkers continued to walk at the same speed, with the same precision as before and were more aware of their movements than non-sleepwalkers,” said Olaf Blanke, a neuroscientist at EPFL. Furthermore, sleepwalkers were more accurate at detecting changes in the VR feedback when faced with the mental arithmetic task.