Under-pruning is associated with which condition due to excess synapses?

Under-pruning is associated with which condition due to excess synapses?

• A. Autism
• B. Schizophrenia
• C. Alzheimer disease
• D. Parkinson disease

Answer: (A)

Synaptic pruning during development eliminates excess connections to refine neural networks. When pruning is underactive, too many synapses remain, leading to atypical brain connectivity. This pattern has been linked to autism spectrum disorder, where increased synaptic density and abnormal connectivity are observed in multiple brain regions. The result can be strong local connectivity but disrupted integration across distant areas, contributing to social communication difficulties and restricted, repetitive behaviors. In contrast, schizophrenia is often associated with excessive pruning during adolescence, reducing synaptic connections; Alzheimer disease involves progressive synapse loss from neurodegeneration rather than a pruning failure; and Parkinson disease centers on dopaminergic neuron loss with motor and non-motor symptoms, not primarily pruning abnormalities.

Synaptic pruning during development eliminates excess connections to refine neural networks. When pruning is underactive, too many synapses remain, leading to atypical brain connectivity. This pattern has been linked to autism spectrum disorder, where increased synaptic density and abnormal connectivity are observed in multiple brain regions. The result can be strong local connectivity but disrupted integration across distant areas, contributing to social communication difficulties and restricted, repetitive behaviors. In contrast, schizophrenia is often associated with excessive pruning during adolescence, reducing synaptic connections; Alzheimer disease involves progressive synapse loss from neurodegeneration rather than a pruning failure; and Parkinson disease centers on dopaminergic neuron loss with motor and non-motor symptoms, not primarily pruning abnormalities.