The physiology of brain protection is not yet well understood. The work of Tobiansky and his colleagues suggests that steroid hormones such as androgens and estrogens may have protective effects on the birds’ brain. So even subconcussive events can have a detrimental effect on the brain, and woodpeckers may have some yet-to-be-determined physiological mechanisms that protect their brain from these repeated subconcussive insults. “The key is that the head of the woodpecker is just much smaller than that of a human.”īut Tobiansky notes that among football players, the brain injury chronic traumatic encephalopathy (CTE) is most commonly found in offensive linemen who receive repeated, subconcussive shocks. So “they could hit the tree at higher speeds and still not suffer a concussion,” he says. Based on the models, the forces woodpeckers’ brain sustains are below the danger threshold by a factor of two. The length of their brain is about one seventh that of a human, which means that they can withstand forces that are seven times higher, Van Wassenbergh explains. For people, an impact of about 135 g’s produces a concussion. So how do woodpeckers avoid concussions? The researchers used simulations to calculate the impact on the brains of the birds and compared it with thresholds for concussion-causing forces in humans. Mary’s College of Maryland and was not involved in the study. Previous work in the 1970s had examined this question from a theoretical perspective, but this study is the first to capture high-speed video to determine how much force is being loaded onto the woodpeckers’ bill and separately onto their brain, says neurobiologist Daniel Tobiansky, who studies woodpeckers at St. The results were reported on July 14 in Current Biology. Instead the head functioned like a stiff hammer, with little to no dampening of vibrations. They tracked the motion of different parts of the woodpeckers’ head as the birds hammered the trees and hypothesized that if there was any cushioning going on, it could be confirmed by detection of slower deceleration of the braincase in comparison with the beak upon impact with the wood. To investigate this question, European and Canadian researchers used high-speed video of three species of woodpeckers in action. “So the more you think about it, the less it made sense that there was any shock absorption going on,” Van Wassenbergh says. If the woodpecker absorbs some of the energy it directs at the tree, then less energy is imparted to the tree trunk, and it has to peck even harder to make holes. It’s very important that this business be very efficient,” explains Sam Van Wassenbergh, an evolutionary biomechanicist at the University of Antwerp in Belgium, who led the new study. “What this bird has to do during the entire day is dig holes into the wood. But a new study suggests that their head and beak act like a stiff hammer for optimal pecking performance rather a shock-absorbing system to cushion the brain. The birds’ distinctive drumming and drilling had led researchers to hypothesize that the bone between woodpeckers’ beak and braincase must absorb shocks to protect their brain from concussions. Woodpeckers spend all day hammering their head on tree trunks, using their beak to make holes and digging insects out of those holes for a meal.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |