Neuronal pruning

Neuronal pruning is a natural process during brain development where excess neurons and synaptic connections are eliminated to improve the efficiency of neural circuits. In the context of autism, including regressive autism, altered neuronal pruning has been proposed as a potential contributing factor.

Neuronal Pruning in Autism

1. Hypothesis of Altered Pruning: Some researchers suggest that abnormalities in the neuronal pruning process may contribute to the development of autism. Specifically, it has been hypothesized that either excessive pruning (leading to a loss of necessary neural connections) or insufficient pruning (resulting in too many synapses) could disrupt normal brain function and development (Tang et al., 2014).

2. Evidence from Neuroimaging and Postmortem Studies: Studies using neuroimaging techniques, such as MRI, have observed differences in brain structure and connectivity in individuals with autism. Some findings suggest an overabundance of synaptic connections in certain brain regions, which could be indicative of reduced synaptic pruning (Varghese et al., 2017). Postmortem studies have also reported similar findings, suggesting that reduced pruning may contribute to the atypical brain connectivity seen in autism.

3. Genetic and Molecular Factors: Genetic studies have identified mutations in genes involved in synaptic function and pruning, which may contribute to autism. For instance, mutations in genes like MECP2, SHANK3, and PTEN have been associated with disrupted synaptic pruning and have been linked to autism spectrum disorders (Penzes et al., 2011).

4. Role in Regressive Autism: In regressive autism, where children lose previously acquired skills, disrupted pruning may play a role in the sudden decline of cognitive and social abilities. The exact mechanisms are still under investigation, but it is possible that abnormal pruning could interfere with the stabilization of neural circuits involved in language, social interaction, and behavior.

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.

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.

Neuronal Pruning

Autism Lexicon: Neuronal Pruning: 

Neuronal pruning is the process of selectively eliminating excess synapses and neurons during brain development to optimize neural circuitry. In autism, atypical pruning has been implicated, potentially leading to altered connectivity and information processing in the brain.

PlainSpeak: Neuronal pruning is the brain's way of trimming excess connections to make neural pathways more efficient. In autism, this process may not occur as expected, which could affect how the brain processes information.