What is Neuronal Pruning

What is Neuronal Pruning?

Neuronal pruning is like a natural "trimming" process in the brain that happens as we grow. During this process, the brain gets rid of extra neurons and connections it doesn't need, helping it to work more efficiently. Think of it like pruning a tree to help it grow better.

How is it Related to Autism?
In autism, including a form called regressive autism, there may be differences in this pruning process. Some researchers think that if pruning is either too much or too little, it can cause problems. For example:

• Excessive Pruning: If the brain removes too many connections, important ones needed for learning and communication might be lost.
• Insufficient Pruning: If not enough pruning happens, the brain might end up with too many connections, which can cause confusion and make it hard to process information.

Evidence from Studies:
Studies using brain imaging techniques like MRI have shown that autistics might have more connections in some parts of their brains. This suggests that their brains may not prune as much as they should. Postmortem studies (studies done after a person has passed away) have found similar patterns, supporting the idea that altered pruning could be involved in autism.

Genetic Factors:
Some genes that help control the pruning process have been found to work differently in people with autism. For example, changes in genes like MECP2, SHANK3, and PTEN might lead to problems with pruning and have been linked to autism.

Why is This Important in Regressive Autism?
In regressive autism, where children lose skills they had previously developed, disrupted pruning might play a role. This abnormal pruning could affect the brain areas involved in language, social interaction, and behavior, leading to the sudden changes seen in these children. This explanation helps to understand how natural brain processes like pruning might be different in people with autism, potentially affecting how they learn and interact with the world.

Citations

• Tang, G., et al. (2014). Loss of mTOR-dependent macroautophagy causes autistic-like synaptic pruning deficits. Neuron, 83(5), 1131-1143.
• Varghese, M., et al. (2017). Autism spectrum disorder: neuropathology and animal models. Acta Neuropathologica, 134(4), 537-566.
• Penzes, P., et al. (2011). Dendritic spine pathology in neuropsychiatric disorders. Nature Neuroscience, 14(3), 285-293.