Tag Archives: neuroscience

How songbirds may help build a better hearing aid

Untreated hearing loss can have devastating and alienating repercussions on a person’s life: isolation, depression, sapped cognition, even dementia.

Yet only one in five Americans who could benefit from a hearing aid actually wears one. Some don’t seek help because their loss has been so gradual that they do not feel impaired. Others cannot afford the device. Many own hearing aids but leave them in a drawer. Wearing them is just too unpleasant.

“In a crowded place, it can be very difficult to follow a conversation even if you don’t have hearing deficits,” says UC Berkeley neuroscientist Frederic Theunissen. “That situation can be terrible for a person wearing a hearing aid, which amplifies everything.”

Imagine the chaotic din in which everything is equally amplified: your friend’s voice, the loud people a few tables over, and the baby crying across the room.

In that scenario, the friend’s voice is the signal, or sound that the listener is trying to hear. Tuning in to signal sounds, even with background noise, is something that healthy human brains and ears do remarkably well. The question for Theunissen — a professor who focuses on auditory perception — was how to make a hearing aid that processes sound the way the brain does.

“We were inspired by the biology of hearing,” Theunissen said. “How does the brain do it?”

Songbirds excel at listening in crowded, noisy environments

Humans aren’t the only ones able to hone in on specific sounds in noisy environments. For the past two years, Theunissen and the graduate students in his lab have studied songbirds, which are especially adept at listening in crowded, noisy environments.

By looking at songbird brain imagery, the researchers now understand how chatty, social animals distinguish the chirp of a mate from the din of dozens of other birds.

They were able to identify the exact neurons that tune into a signal and remain tuned there no matter how noisy the environment becomes. These neurons shine what Theunissen calls an “auditory spotlight” by focusing in on certain features or “edges” of a sound. Imagine you are looking for your cellphone on a table covered with objects. In the same way that your eye can find for a specific rectangular shape and color, your ear searches for and finds certain pitches and frequencies: the sound of a friend’s voice in a restaurant.

“Our brain does all this work, suppressing echoes and background noise, conducting auditory scene analysis,” Theunissen says.

A Proof of Concept Commercialization Gap grant from UC Research Initiatives in the Office of the President provided the critical funding the lab needed to take the discovery one giant step farther.

Read How songbirds may help build a better hearing aid →

Neuroscape Lab puts brain activity on vivid display

In Adam Gazzaley’s new lab, the brain is a kaleidoscope of colors, bursting and pulsing in real time to the rhythm of electronic music.

The mesmerizing visual on the screen is a digital masterpiece — but the UC San Francisco neuroscientist has a much bigger aspiration than just creating art. He wants this to lead to treatments for a variety of brain diseases, including Alzheimer’s, autism and multiple sclerosis.

Gazzaley, M.D., Ph.D., opened the Neuroscape Lab in March at UCSF’s Mission Bay campus, where he’s developed a way to display a person’s brain activity while it’s thinking, sensing and processing information, allowing researchers to see what areas of the person’s brain are being triggered — or, in the case of certain diseases, not triggered.

Until recently, it was impossible to study brain activity without immobilizing the person inside a big, noisy machine or tethering him or her to computers. At the Neuroscape Lab, subjects can move freely to simulate real-world conditions.

One of its first projects was the creation of new imaging technology called GlassBrain, in collaboration with the Swartz Center at UC San Diego and Nvidia, which makes high-end computational computer chips. Brain waves are recorded through electroencephalography (EEG), which measures electrical potentials on the scalp, and projected onto the structures and connecting fibers of a brain image created with Magnetic Resonance Imaging and Diffusion Tensor Imaging.

To demonstrate the technology at the lab’s opening, Grateful Dead drummer Mickey Hart donned an Oculus Rift virtual reality headset and played a drumming video game designed to enhance brain function, while colorful images of his brain in action showed on the screen. Video games like NeuroDrummer are an entertaining and accessible way that Gazzaley is developing to train the brain.

“I want us to have a platform that enables us to be more creative and aggressive in thinking how software and hardware can be a new medicine to improve brain health,” said Gazzaley, an associate professor of neurology, physiology and psychiatry and director of the UCSF Neuroscience Imaging Center. “Often, high-tech innovations take a decade to move beyond the entertainment industry and reach science and medicine. That needs to change.”