In the new research, the UCSF neuroscientists used their technology to investigate how the learning process is controlled by the brain. A prevailing theory suggests that new learning is controlled by a "smart" brain structure called the basal ganglia, a cluster of interconnected brain regions involved in motor control and learning.
"It's the first place where the brain is putting two and two together," said Jonathan Charlesworth, a recent graduate of UCSF's neuroscience PhD program and the first author of the new paper. "If you remove the basal ganglia in a bird that hasn't yet learned to sing, it will never learn to do so."
Once a basic, frequently repeated skill such as typing, singing the same song or shooting a basketball from the free-throw line is learned, the theory suggests, control of that activity is carried out by the motor pathway, the part of the nervous system that transmits signals from the brain to muscles. But for the basic routine to changefor a player to shoot from another spot on the basketball court or a bird to sing at a different pitchthe basal ganglia must again get involved, providing feedback that allows learning based on trial and error, the theory suggests.
What remained unclear is what makes the basal ganglia so "smart" and enables them to support such detailed trial-and-error learning. Was it something to do with their structure? Or were they getting information from elsewhere?
The scientists sought to answer this question by blocking the output of a key basal ganglia circuit while training male finches to alter their song using the white-noise blasts. As long as the basal ganglia were kept from sending signals to the motor pathway, the finches didn't change their tune or show signs of learning. But when Brainard's team stopped blocking the basal ganglia, something surprising happened: the finches im
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University of California - San Francisco