Long Term Potentiation - An Overview

Introduction to LTP

• Definition: Persistent increase in synaptic strength.
• Duration: Can last from a few hours to days or months.
• Often studied in relation to learning and memory.

Mechanisms of LTP

• Hippocampus: Fundamental cellular model for learning and memory.
• Pain Pathways: Involved in pain amplification and hyperalgesia.
• Reversibility: LTP and LTD can be reversed, indicating common expression mechanisms.

Types and Induction of LTP

Heterosynaptic LTP

• Characteristic: Not input specific, affects unstimulated pathways.
• Significance: Less considered for associative learning in mammals but potential role in modulating synaptic modifications.

Mossy Fiber LTP

• Discovery: 1970s, distinct from CA1 region LTP.
• Characteristics: Does not require NMDA receptor activation.
• Expression: Increased glutamate release probability at presynaptic terminals.

Molecular Mechanisms

• NMDA Receptors: Crucial for induction; NMDA antagonists impair spatial navigation and stability of place fields.

LTP Beyond the Hippocampus

• Cerebral Cortex & Amygdala: Role in visual/sensory system development and fear conditioning.

LTP and Synaptic Plasticity

• Actin Remodeling: LTP involves structural changes such as spine duplication and actin filament elongation.
• AMPA Receptors: Regulated in LTP, LTD, depotentiation, and dedepression.

LTP in Pain and Migraine

• BDNF Role: BDNF plays a role in LTP and pain plasticity.
• Migraine Connection: BDNF and CGRP interaction contributes to migraine-related changes.

Summary

• LTP and LTD are rapidly evolving fields.
• Understanding involves multiple receptor types and molecular mechanisms.
• Further research is needed to clarify varieties and establish links to information encoding and retrieval.