• Scientists have found out that spectrin, which are flexible rod-shaped molecules present in axons, act as ‘shock absorbers’ to protect axons from stretch-induced damage.

What are Axons?

• Axons are long tubular extensions of nerve cells that transmit electrical signals across long distances and can be up to a meter long in the case of humans.
• At such lengths, they are subjected to large stretch deformations during limb or other bodily movements.
• Axons in the brain too undergo significant deformations, even during normal activities like jumping (the human brain is as soft and wobbly as edible jelly).

Key-findings of the probe:

Probing into what special strategies axons adopt to protect themselves from damage during such stretch deformations, the scientists zeroed in on the molecule spectrin, a cytoskeletal protein.

• The neuronal cells may have evolved a clever strategy using an etched optical fiber attached to a piezo drive as a force-sensing cantilever to stretch live axons and to measure the resultant tension.
• Piezo drives attached to optical fiber is used to stretch on axons where optical fiber acts as a force-sensing cantilever.
• The resulting tension measured along the axon comes from the axonal cytoskeleton (consisting of biopolymers), of which spectrin is a part.

This study will have significant implications to our understanding of concussion that result from head impacts as well as stretch-induced nerve injuries.