Long-standing beliefs about the ability of the brain to generate new cells have recently been challenged by research into birdsong.

Wednesday night, as part of the yearlong “Music and the Brain” series, Fernando Nottebohm of The Rockefeller University in New York City gave a lecture titled “For Whom the Bird Sings.” The lecture dealt directly with the neurological responses in birds that help to demonstrate the non-plasticity of the human mind.

“There’s a subset of neurons in the brain — that belong to a replaceable set,” he said. “Reusable neurons allow you to jettison old memories and acquire new ones.”

In one experiment Nottebohm described, the auditory organs of male birds were removed and the birds were divided into two groups by age. The experiment was designed to determine how long the birds would be able to retain their song after they could no longer hear.

The results showed that in adult birds, song was maintained for a year before it started to break down. However, for 6-month-old birds, who had only known their song for a few months, they started to lose their song within a few weeks.

“The number of new cells coming in gradually decreases with age,” Nottebohm explained. “You remember longer because there are fewer new cells coming in.”

Yale School of Medicine professor Thomas P. Duffy, who helped to organize the series, said Nottebohm is known in the field of neurobiology as “the birdman.”

“He made one of the most important observations that has overturned one of the dogmas of neurobiology: the non-plasticity of the brain,” he said.

Thomas C. Duffy, co-organizer of the event and deputy dean of the Yale School of Music, said that although there was no particular musical component to the lecture, Nottebohm’s expertise dealt directly with the entire theme of the series.

“We tried to bring him in as a form of closure for the series,” he said. “He provides an expertise on how birdsong relates to humans and their physiology.”

The yearlong “Music and the Brain” series is a collaboration between the medical school and Music School. Recent discoveries of a potential link between birdsong and the reversal of neurological disease helped to inspire the series.

Nottebohm said his initial interest in birdsong came from a curiosity about how the birds’ vocal organs function. Later, he began working with the connections between humans and birds, especially in terms of vocal and hemispheric learning.

Nottebohm’s research deals directly with the impetus for the lectures.

The case of Hikari Oe, a mentally-retarded boy who experienced some of the positive neurological effects of music, was particularly influential in the development of the lecture series.

Oe’s father, Kenzaburo Oe, received the Nobel Prize in literature in 1994. His novel, “A Personal Matter,” describes Oe’s birth, his disability and his subsequent healing with the help of birdsong.

During his Nobel lecture, Oe described how his son first spoke at age six, when he was able to identify a certain bird by its song.

“This was the first moment my son ever uttered human words,” Oe said. “It was from then on that my wife and I began having verbal communication with our son.”