Songbirds could hold key to curing speech impediments

By Mark Waghorn via SWNS

Birds could hold the key to curing stammers and other speech impediments, according to new research.

Our feathered friends use specialized cells within the brain to pick up songs.

They are similar to those in the cortex of the human brain linked to fine motor skills.

The neurons shed fresh light on the mechanisms involved when the connection goes awry.

Mutations that affect them lead to stuttering - which can be overcome by learning, say scientists.

Others have more potentially pronounced effects - such as those involved in progressive disorders like motor neurone disease.

Roughly three million Americans have a stutter, according to the NIH.

Famous sufferers include US president Joe Biden, actor James Earl Jones and actress Emily Blunt.

Britain's King George VI found it difficult to give public speeches due to his stammer and underwent speech therapy.

After centuries of misunderstanding, research is finally tying the disorder to certain genes and brainwaves - offering hope of better treatments.

Speech is the most complicated fine motor skill we have. It can also be affected by autism, strokes and dementia.

Muscles in the jaw, lips and tongue have to perform rapid and precise movements so a word is produced with appropriate clarity.

Now a study has identified the cells within neural circuitry that trigger complex learning in songbirds.

They generate electrical signals between cells in the nervous system at extremely high speeds and frequencies as the bird sings.

The study describes "ultrafast spikes" that only last 0.2 milliseconds. Others take at least five times longer. A millisecond is a thousandth of a second.

They also bear a striking resemblance to a type associated with the development of fine motor skills in humans.

Co-senior author Dr. Henrique von Gersdorff said: "These are the properties you need if you want to have a male song that's precise and distinct so the female can choose which bird she wants to mate with.

"You need a highly specialized brain to produce this."

The Oregon Health & Science University team found the assemblage involved in the male zebra finch's singing closely resembles neurons known as Betz cells in the human brain.

They have long, thick nerve fibers called axons that propagate spikes at very high velocities and frequencies - important for hands, feet, finger and wrist dexterity.

Co-senior author Professor Claudio Mello said: "Think of a piano player. They are thinking so fast, they have to rely on memories and actions that are learned and stored. Playing the guitar is the same thing."

The serendipitous discovery was made after Dr von Gersdorff showed him a brain image of a young male zebra finch at an age just before he could sing.

Another revealed a telltale subunit of proteins that had materialized after the bird was old enough to begin singing.

von Gersdorff said: "Something remarkable was happening in a period of just a few days.

"I said, this is exactly the protein we’ve been studying in the rodent auditory system. It promotes high-frequency spiking."

The study in Nature Communications deepens scientific understanding of the learning of fine motor skills.

Mello said: "This is a very important model, and we think this new study has broad potential."

The motor circuit properties are shared by species that diverged more than 300 million years ago.

Neuronal properties in the male zebra finch may become optimized for speed and precision through convergent evolution.

The phenomenon is the process by which two unrelated species evolve similar features to adapt to problems or habitats.