How Are Memories Made? Chromatography Explores

They say the best thing about memories is making them. What’s less clear is how exactly that’s done. Sure, you can get all your friends together, pack up the car for a spontaneous weekend away or book a once-in-a-lifetime holiday. But what actually happens in the brain to form those memories in the brain?

It’s all in the fat

If there’s one thing scientists do know about memories, it’s that they’re formed in the brain. It’s also become clear from other research that polyunsaturated free fatty acids (FFAs) have a role to play in learning and memory. That’s because they act as modulators for neurotransmission and synaptic plasticity.

This will come as no surprise to anyone who knows their stuff about brains. After all, it’s made up of around 60% fat, making it the body’s fattiest organ. What you won’t know, however, is the precise nature of those changes within the brain, including how and where they happen.

Testing fats with rats

To find out more, a group of researchers from the University of Queensland studied the level changes in FFAs and phospholipids across rat brains during auditory fear conditioning (AFC).

They used ion fragmentation with liquid chromatography mass spectrometry (LC-MS) to identify and quantify the phospholipids. This use of LC-MS at a molecular level is discussed in the article, ‘LC-MS Analysis of Therapeutic Oligonucleotide and Related Products. A comparison of TQ and Q-TOF Systems’.

The team also used FFAST – a sensitive isotope labelling multiplex analysis of FFAs – to map the distribution of 18 FFAs within the rat brain, and how they responded to learning through AFC.

Changes in the amygdala

Combining the two methods, researchers found that the highest phospholipid and FFA concentrations were in the amygdala and prefrontal cortex. The amygdala is the part of the brain associated with memory formation, while the pre-frontal cortex is renowned for a focus on immediate cognitive processing.

The most marked changes were those in saturated FFAs like myristic and palmitic acids. Crucially, levels didn’t change when learning was inhibited using a drug to block memory formation. The findings suggest that an increase in phospholipid-derived FFA could play a central role in learning and memory formation.

The study claims to provide “the first brain-wide profile of FFA changes with learning.” With further studies, and new developments in lipidomics techniques, it’s hoped researchers could uncover the specific roles of FFAs in learning and memory. In years to come, this could become a stride forward in the understanding and treatment of neurological disorders such as dementia.