Practicing a motor activity, whether it is a piano concerto or a golf swing, involves doing two things at once: experimenting with possibilities and evaluating the results. Baby birds, too, use both exploration and analysis as they learn to sing, producing a torrent of sounds that gradually converge into the characteristic song of their species.
Research with zebra finches has shown that a part of the brain comparable to the human basal ganglia is crucial in song learning, but whether this area provides the creativity or objectivity has been open to debate.
According to a study published in the May issue of Public Library of Science Biology, the area in question, a brain pathway called the lateral magnocellular nucleus of the nidopalium (LMAN) produces the astonishing variability with which baby birds experiment. Michale Fee and colleagues at the Massachusetts Institute of Technology and Harvard University used a quick-acting injection to temporarily block signal transmission in the LMAN of young zebra finches. The result was a striking decrease in variability in the birds’ songs.
In normal, young birds the recorded activity of LMAN neurons was highly “noisy.” In addition, earlier findings show that stimulating the LMAN of older birds produces transient changes in the song. The authors say these observations taken together make LMAN a likely source for variability rather than evaluation.
“These results show how the brain produces the explorations needed to learn complex behaviors in ways that are relevant to humans,” Fee says. Because the basal ganglia plays a role in motor disorders such as Parkinson’s disease and in conditions involving repetitive movement patterns, such as obsessive-compulsive disorder, a clearer understanding of its circuitry may benefit patients with these disorders.