Woodpeckers’ Skulls Don’t Prevent Brain Damage, Study Finds

The downy woodpecker. (Copyright Arlene Koziol, The Field Museum)

(CN) – A new study suggests that modeling sports helmets after the skulls of woodpeckers may not be the whole answer to protecting athletes’ brains from injury.

The report, published Friday in the journal PLOS One, presents new findings on how the birds’ brains respond to pecking wood, and what that can teach us about brain injuries in humans.

While woodpeckers’ skulls are tough, they do not protect against the long-term build-up of tau, a protein associated with brain damage in humans. The question is, do they need to?

“There have been all kinds of safety and technological advances in sports equipment based on the anatomic adaptations and biophysics of the woodpecker assuming they don’t get brain injury from pecking,” said author Peter Cummings, a neuropathologist at Boston University.

“The weird thing is, nobody’s ever looked at a woodpecker brain to see if there is any damage.”

When the birds peck wood, they experience a force of 1,200 to 1,400 g’s – a measurement of the form of acceleration that causes a perception of weight. A force of 60 to 100 g’s can give a human a concussion.

Using bird brains from collections at the Harvard Museum of Natural History and the Field Museum, the team investigated how such collisions impact the brains of both woodpeckers and humans.

“The basic cells of the brain are neurons, which are the cell bodies, and axons, which are like telephone lines that communicate between the neurons,” said lead author George Farah, who worked on the project as a graduate student at Boston University. “The tau protein wraps around the telephone lines–it gives them protection and stability while still letting them remain flexible.”

At normal levels, tau proteins can be help stabilize brains cells. But a build-up of too much of the protein can disrupt communication from one neuron to another.

“When the brain is damaged, tau collects and disrupts nerve function – cognitive, emotional, and motor function can be compromised,” Cummings said.

Since an elevated level of tau can be a sign of brain injury in humans, the researchers decided to examine woodpecker brains for tau buildup.

The museums loaned bird specimens pickled in alcohol – red-winged blackbirds, which are not prone to head injuries, as a control, and downy woodpeckers for the experimental data – and the team removed the brains.

“The brains themselves were well-preserved, they had a texture almost like modeling clay,” Farah said.

The researchers took thin slices less than a fifth of the thickness of a sheet of paper of the brain tissue and stained them with silver ions to expose tau proteins. The woodpeckers’ brains had much more of the protein than did the blackbirds’ brains.

Though this level of buildup can be a sign of brain injury in humans, the team notes that it might not be for woodpeckers.

“We can’t say that these woodpeckers definitely sustained brain injuries, but there is extra tau present in the woodpecker brains which previous research has discovered is indicative of brain injury,” said Farah.

Cummings wonders why the birds would continue to peck wood if doing so causes them brain damage.

“The earliest woodpeckers date back 25 million years; these birds have been around for a long time,” he said. “If pecking was going to cause brain injury, why would you still see this behavior? Why would evolutionary adaptations stop at the brain?

“There’s a possibility that the tau in woodpeckers is a protective adaptation and maybe not pathological at all.”

While it is unclear whether tau buildups negatively impact woodpeckers, the team believes that their findings could help humans.

Cummings notes that the greater knowledge of the birds’ brains could help make helmets safer for kids, or provide insight into treating people who have developed Alzheimer’s, Parkinson’s or other neurodegenerative diseases.

He asks, “If the tau accumulation is a protective adaptation, is there something we can pick out to help humans with neurodegenerative diseases?

“The door’s wide open to find out what’s going on and how we can apply this to humans.”

 

%d bloggers like this: