How Brain Cells Reorganise Energy Factories to Store Memories

New imaging technology is finally shedding light on the minute physical changes that occur inside our brains when we learn. Until recently, observing the nanoscopic machinery within neurons with such precision was largely restricted to cells grown in a dish. Now, researchers have successfully applied MINFLUX—a cutting-edge microscopy method that bypasses the traditional limits of light diffraction—to fixed brain tissue.

The study focused on the dentate gyrus, a brain region crucial for memory, specifically looking at 'engram cells' which hold memory traces. The team discovered that mitochondria, the famed powerhouses of the cell, are far from static. During synaptic plasticity—the strengthening of connections between neurons—proteins within the mitochondrial inner membrane undergo significant reorganisation. Specifically, α-F1-ATP synthase, the enzyme responsible for generating cellular energy, was seen clustering near the postsynaptic zone.

This redistribution suggests a logistical strategy: the neuron polarises its energy production, moving the 'power plant' directly to where fuel is needed for memory consolidation. Using dual-colour imaging, the team found that these structural shifts involve both the inner and outer mitochondrial membranes. In neuronal cultures, these patterns were shown to persist for up to 12 hours, highlighting a durable regulatory mechanism. These findings demonstrate that memory is not just an electrical signal, but a complex physical reordering of the cell’s energy infrastructure.