How does your brain store long-term memories?

Long-term memories are stored through a process called synaptic consolidation, where repeated neural activity strengthens connections between neurons. When you experience something, neurons fire together and release neurotransmitters that trigger structural changes at synapses, making those connections more efficient over time. This follows the principle often summarized as "neurons that fire together, wire together." The hippocampus plays a central role in initially encoding and organizing memories, but over time memories become distributed across the cortex through a process called systems consolidation. Sleep is particularly important here, as the brain replays experiences during slow-wave sleep to transfer memories from the hippocampus to long-term cortical storage. Proteins like BDNF and changes in gene expression help physically reinforce these synaptic changes permanently.