Long-term depression

Long-term depression (often abbreviated as LTD) is a process that results in the decrease of synaptic strength, which is the opposite of long-term potentiation (LTP). LTD and LTP are both forms of synaptic plasticity, the ability of synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTD and LTP are considered to play a major role in memory formation and learning.

Mechanism

The mechanisms underlying LTD vary and can be chemical or non-chemical. In chemical LTD, the decrease in synaptic strength is achieved by reducing the amount of neurotransmitter released by the presynaptic neuron, reducing the sensitivity of the postsynaptic neuron to the neurotransmitter, or both. Non-chemical LTD can occur through the loss of synapses or the conversion of large synapses into several smaller ones.

Role in Learning and Memory

LTD is thought to play a major role in memory formation and learning. It is one of the major cellular mechanisms that underlies the ability of the brain to adapt to new information and experiences. LTD is also thought to be involved in the forgetting of old memories, as it can lead to the weakening or elimination of synapses that are no longer needed.

Clinical Significance

Abnormalities in LTD have been implicated in a number of neurological and psychiatric disorders, including Alzheimer's disease, Parkinson's disease, schizophrenia, and depression. Understanding the mechanisms of LTD could therefore lead to new treatments for these conditions.

See Also

• Long-term potentiation
• Synaptic plasticity
• Neurotransmitter
• Alzheimer's disease
• Parkinson's disease
• Schizophrenia
• Depression

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Long-term depression

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