It was found that some neurons have the ability to compensate for the death of neighboring neurons.
Our brain is a complex network of billions of neurons that constantly transmit information through synapses. Several neural pairs that innervate individual muscles in a fruit fly model have been studied.
To better understand how the brain adapts to structural and functional changes, the neuromuscular system of the fruit fly was studied, where each muscle is innervated by two motor neurons. Removing individual neurons without simultaneously destroying other neurons is difficult, and it is also difficult to measure the underlying activity of a single neuron.
By expressing genes that promote cell death in a very specific subgroup of motor neurons. An image and electrophysiological recordings were used to isolate the activity of the only remaining neuron in the pair.
The results of the study are a step in understanding brain plasticity and using this knowledge to better understand not only normal development, but also neurodegenerative diseases. In one of the muscles, it was recorded how the remaining neuron expanded its synaptic branch and compensated for both spontaneous and induced neurotransmission of the neighboring neuron. However, when they performed the same procedure on two other muscles, they found that the remaining neuron did not compensate for the loss of the neighboring neuron.
Some neurons have the ability to detect and compensate for neighboring neurons, while others do not. This may be due to the fact that each neuron has different functional properties. The neuron that compensated for the loss of the neighboring cell also contributed the most to the overall activity of the muscle in the initial conditions. It can be assumed that pairs of neurons work together to establish a “reference point” for activity during circuit formation. If the neighboring neuron never forms synapses — if the system never knew that it should receive information from two neurons — then the remaining neuron will not compensate for this.
Further research will help determine whether neurons whose neighbors are affected by neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), which causes progressive neuron death and loss of muscle function, may exhibit synaptic plasticity. The mechanism that causes compensation will be studied.