A new finding that motor cortex is a dynamic pattern generator upends existing theory with broad implications for neuroscience.
In a series of striking graphs, the Stanford team plotted the signals from individual neurons in the motor-cortex as monkeys completed a series of reaches. The reaching motions are shown by the starburst patterns at the top left of each graph. The neuronal patterns are then plotted atop one another for the entire series of reaches, clearly establishing the rhythmic nature of the brain activity.
Unlike their visual cousins, the neurons that control movement are not a predictable bunch. Scientists working to decode how such neurons convey information to muscles have been stymied when trying to establish a one-to-one relationship between a neuron's behavior and external factors such as muscle activity or movement velocity.
In an article published online June 3rd by the journal Nature, a team of electrical engineers and neuroscientists working at Stanford University propose a new theory of the brain activity behind arm movements. Their theory is a significant departure from existing understanding and helps to explain, in relatively simple and elegant terms, some of the more perplexing aspects of the activity of neurons in motor cortex.