A protein, known as netrin, is said to strengthen the connections occurring between the brain cells.
This finding has been revealed in a recent research supervised by the Montreal Neurological Institute and Hospital, a research and teaching institute working in Canada.
Scientists were already aware that netrin is important for the development of both embryonic as well as the infant’s brain. Here, this protein aids in making connections between neurons, the brain cells.
The recent research highlights that this protein can also strengthen the synapses of neuronal connections in the hippocampus of an adult brain. This is the area that is crucial for the process of learning and memory.
The paper was published by the journal named Cell Reports.
According to the scientists, it was previously considered to be a mystery why neuron continue making netrin in the adult brain ever after the establishment of all the connections during infancy.
Molecule Key for Strengthening Synapses
As per the lead scientists, a neuron produces and releases netrin when it is in an active state. This protein, in turn, strengthens the connection to a surrounding neuron by signaling the two neurons to make their synapse stronger.
This recent study has followed the train of work that initiated almost seven decades ago when a psychology professor named Donald Hebb put forward his idea of how the brain works to learn and form new memories.
His idea was later known as the Hebbian Theory and aimed to explain the methods through which the neural circuits form as a consequence of experience.
Hebb mentioned that the weakness or strength of synaptic connections depends on the frequency of their usage. The more they are used, the faster and stronger they become.
The psychology professor later published a book in 1949 in which he attempted to describe the process of synaptic strengthening. He explained that as one neuron gets close enough to another and keeps firing it, a metabolic change or a growth process takes place in one cell or both of them.
The scientists leading the current study are of the viewpoint that this mechanism that was discovered 69 years ago is what forms the basis of this theory.
Synaptic Changes Underlie Memory and Learning
The idea that the hippocampus in the brain plays an important role in certain types of learning and memory was put forth in 1957 by Brenda Miller who completed her doctorate under Hebb’s supervision.
If you boil this down to one molecule. The release of netrin is important for the synaptic changes underlying the changes in a neuron which are involved in memory and learning.
The scientists also observed that to strengthen the synapses, netrin needs to be released into the extracellular spaces.
This made the investigators think about other additional opportunities for interacting with other neurons that this would provide.
Gene studies have already implicated the involvement of netrin in diseases that destroy brain tissue such as Parkinsonism, amyotrophic lateral sclerosis and Alzheimer’s disease. However, no mechanisms have been identified as yet.
Previously Undiscovered Target
Overall speaking, the work advances the understanding of the scientific community about how the brain forms memories and stores them. It also offers a new target for the diseases affecting memory function which remained under the shadows for years.