Just keep putting one foot in front of the other. Seems like simple advice, but the act of walking is far from straightforward.
In fact, walking is a complex process involving many different parts of the brain. The process of initiation and continuous adaption keeps us moving (and normally upright) on snowy sidewalks, while carrying shopping bags, or when hurrying for a bus.
Until recently, the brain’s motor cortex was thought to be the primary area regulating voluntary movements like locomotion. But researchers from the University of Toronto and the Krembil Research Institute have discovered that another network also plays a role.
The team, led by senior scientist Dr. Michael Fehlings, studied the somatosensory cortex in mice. This area processes sensations like touch and temperature, as well as visual stimuli, but the researchers spotted a strong correlation between somatosensory activity and locomotion.
The link itself is not necessarily surprising. The sensory cortex receives and integrates huge quantities of information about our ever-changing environment, information that keeps us moving smoothly.
The surprise was that the somatosensory activity always started before the movement. According to the researchers, this order suggests that the sensory cortex can actually trigger walking.
Looking deeper using optogenetics, pharmacogenetics and electrophysiology, the researchers found that these movement commands travel directly to the spinal cord, completely bypassing the motor cortex.
“Our data support a potential mechanism through which the sensory cortex can directly and efficiently control walking in response to the sensory information that is continuously processing,” says Fehlings.
This new and independent pathway for initiating and directing movement is, excuse the pun, an exciting step forward. There is much more work to be done before we truly understand the complexities of how our brain controls locomotion, but this discovery opens new avenues for investigating how we walk and what happens when it goes wrong.