A new study finds that motor neurons encode the world differently from other types of brain cells.
How do neurons firing in the brain produce movement in the body? For years, scientists trying to establish a one-to-one relationship between a neuron's behavior and factors such as muscle activity or speed of movement, have come up empty. The sorts of discoveries that have illuminated the neural circuitry behind vision have eluded scientists studying how we move, largely because of the unpredictability of the neurons that control movement.
But a game-changing new conceptualization of how brain activity translates into motion by a team of electrical engineers and neuroscientists may finally offer an explanation of activity in the motor cortex that has long bewildered scientists.
'Each neuron behaves like a player in a band. When the rhythms of all the players are summed over the whole band, a cascade of fluid and accurate motion results.'
- Brain Cells Benefit From the Company of Others
- When Neurons "Nap" Mistakes Are Made
- In Sports, Practice Makes Perfect If You Mix It Up
The researchers, working at Stanford University, found that when directing arm movement, the motor cortex does not encode neurons based on spatial information such as direction, distance and speed the way visual neurons do for color, intensity and pattern. "Visual neurons encode things in the world. They are a map, a representation," said Mark Churchland, now a professor at Columbia and first author of the paper, in a press release. As closely as they looked at the behavior of motor neurons connected to arm movement, no rules for firing similar to those of visual processing emerged.