Mechanical brain concept
Anil Ananthaswamy based on William Tyler
New Scientist, 31 August 2013
Tyler’s position is that brain processing is mechanically sensitive. He argues that in addition to the well known electrical and biochemical signalling between neurons, the neurons may also be part of a mechanical network. He thinks that such a network might be involved in memory storage and responses to new circumstances.
Some studies carried out by Tyler suggested that mechanical forces in the form of ultrasound waves could stimulate neurons to fire. In some organisms, a mechanical wave has been observed to accompany action potentials. This is proposed to explain the lack of heat loss during action potentials. The dendritic spines that receive signals from other neurons, themselves sway and pull on neighbouring molecules. It is suggested that there might be mechanical communication between neighbouring dendritic spines. The dendrites are filled with actin which can form into long polymers, and this process may be capable of making the spine bend, expand, or contract, in the process of communicating.
It is suggested that this could allow an additional route for signalling with some signals going through to synapses. A chain of adhesive proteins are present in the actual synapse, and this means that a movement in the dendritic spine could react back onto the preceding axon terminal. Such forces could influence the number of neurotransmitter molecules released across a synapse.