What is the Origin of Synaptic Loss?

The term is fundamental to cellular and molecular neuroscience, describing the structural basis of cognitive decline. Synapses are the essential functional units of the nervous system. Their loss is considered a more accurate correlate of cognitive impairment than the loss of neurons themselves. Research in this area is focused on understanding the role of glia and hormones in synaptic pruning and maintenance.

What is the Mechanism of Synaptic Loss?

Synaptic loss can be triggered by chronic neuroinflammation, oxidative stress, and the accumulation of toxic protein aggregates. Microglia, the brain's immune cells, can become overactive and pathologically prune healthy synapses. Furthermore, the decline in neurotrophic factors, such as BDNF, and the loss of protective sex hormones, like estrogen, reduce the molecular signaling required for synaptic maintenance and growth. This failure of structural integrity directly compromises the brain's computational capacity.

Synaptic Loss ∞ Area

Synaptic Loss

Meaning

Synaptic loss refers to the pathological reduction in the number or density of synapses, the specialized junctions through which neurons communicate with each other, leading to a breakdown in neural circuit integrity. This loss is a key early feature of neurodegenerative diseases and is also associated with normal aging and chronic hormonal imbalances. It directly impairs cognitive functions, including memory, learning, and processing speed.