Long-term depression (LTD) is a process in which synaptic strength decreases over time, leading to a reduction in the efficiency of communication between neurons. This phenomenon is essential for various brain functions, including learning and memory, as it helps to fine-tune neural circuits by weakening less important connections. LTD is often studied in the context of neuroplasticity, the brain's ability to adapt and reorganize itself. It can occur in response to specific patterns of activity and is thought to play a role in conditions such as Alzheimer's disease and other cognitive disorders, where synaptic function is impaired.