To understand how the brain forms memories and how humans and other animals learn, we need to look at a range of levels. We can use educational and behavioral studies to know what is effective in practice; we can study the regions of the brain most active during different types of learning to know where that learning takes place; and we can look at what changes at synapses, the junctions between neurons, to know how the brain learns and remembers. This paper investigates the last of these, looking at a specific molecule, BDNF, that is found at synapses.
Most researchers think that to form memories, synapses need to change. One way for these connections to change is through a process called LTP (long-term potentiation), which is a long-lasting increase in how effectively particular brain cells talk to each other. LTP is like turning up the volume knob of a conversation. With the volume turned up, messages can get through more easily, meaning that what used to be faint hints of a conversation (for example, a brief thought) can be heard throughout the room (trigger an entire event to be recalled).
LTP can be separated into early and late phases. Late-phase LTP (L-LTP), the focus of this article, is what makes LTP particularly long-lasting and therefore what makes it a candidate for long-term memories. This study looked at the involvement of a particular molecule, BDNF (brain-derived neurotrophic factor), in late-phase LTP.
The key finding of this research is that BDNF is needed at two different stages within L-LTP, and at two different locations, to keep the synapses strong – to keep the volume turned up. BDNF, a molecule well-known to be important in memory formation, therefore seems to be a more versatile contributor than first thought.
The bigger picture
In the short term, studies like this are about building the knowledge for other scientists to work from, so that they can delve ever deeper into what exactly is going on in our brains when we learn. In the long term, understanding the molecules needed for learning might help us develop drugs for treating memory disorders as diverse as Alzheimer’s disease or post-traumatic stress disorder. It’s even conceivable that if we know where, when and why certain molecules affect memory, we could enhance the process.
There are all sorts of complications and ethical considerations here, and as a disclaimer of sorts, most researchers in the field simply aren’t motivated by the thought of turning humans into super-memorizers. Still, it’s certainly true that without knowing these details of the memory and learning processes, such possibilities are far, far less likely.