A bird’s eye view (of tau)
The cause of brain damage resulting from repeated concussions in contact sport athletes is a current research hot topic. A potential culprit is tau, a protein whose accumulation in the human brain has been observed as part of the normal aging process but also with neurodegenerative diseases and brain damage. Some tau is needed for neuron function but an aggregation of the protein may be responsible for symptoms of neurodegeneration.
In recent years, woodpeckers have been used as a model for the development of safety equipment (e.g., football helmets) because these birds appear to have evolved biophysical mechanisms, such as thick neck muscles, that protect them from brain damage despite experiencing enormous forces while pecking wood. The neurobiological impacts of pecking behaviour have largely gone unexplored, however.
Farah and colleagues (2018) sought to establish if tau accumulations exist in the brains of woodpeckers. Using museum specimens, they identified positive silver staining consistent with tau accumulations in 8/10 woodpecker samples, while an immunohistochemistry assay confirmed tau in 3 of the samples. Identified anatomic locations and staining patterns of lesions further shared some similarities to human brains exposed to repetitive mild traumatic injury.
Many questions remain, however. Larger sample sizes are needed to confirm findings and establish the type of tau, protective or toxic, present in woodpecker brains. Woodpeckers may also have evolved a modification that mitigates the accumulation of tau. Nonetheless, this research has implications for brain injury research and research into neurodegenerative diseases.