New Theory of Memory Formation

Have we been looking at the topic of memory formation from the wrong perspective? For many years it was thought that synaptic plasticity was the main mechanism by which memories are formed in the brain – potentially through a process known as long-term potentiation (LTP), whereby connections between synapses are strengthened due to repeated stimulation. A new study, however, suggests that some neurons display characteristics which make them predisposed to join networks of learning. William Frost PhD, a main contributor to this research, described neurons as displaying “a surprising ambivalence about their commitment to the network’s function”. Why would neurons behave in such an indecisive way?

The study to answer this question was conducted at the Rosalind Franklin University of Medicine and Science by Evan Hill et al. They used a voltage-sensitive dye to observe the behaviour of neurons following short-term sensitization of the swim motor program of the sea slug Tritonia. It was found that after learning had occurred, the number of neurons participating in this particular learning network had rapidly increased, and the additional neurons were the aforementioned “ambivalent” neurons, which had been converted from a variably committed state to a reliable state (that is, they were now committed to serving a function within the particular network being studied). This conversion was thought to be brought about by a serotonergic cellular mechanism.

These results suggest that particular neurons in the brain may possess certain properties that may enable them to serve a variety of functions, and they can be reassigned functions when required (to form a memory). This has promise for research into treatments for brain injury, in that neurons could potentially be experimentally prompted to join certain networks and restore brain functions that were impaired by the injury.