Does white/grey brain matter changes in aging make you bad at learning?



Does white/grey brain matter changes in aging make you bad at learning?

In: Biology

The myelin coated white matter transmitting the information and the grey matter bathed in oxygenated blood processing the information.

The white and grey matter does change as you age and has impact in your memory retention. But the learning part is effected by a different mechanism.
When you are a kid your brain is very flexible in the way it wires and rewires, making you very adapt at learning new things. As you age, the neutral connections in the brain become more and more strengthen, allowing you to do a number of tasks without much of a mental effort, something we usually call muscle memory. A downside to that is that your ability to learn new things go down.

I’m not sure if they really know that yet. I believe the current working theory is that you are born with some number of neurons, but no heavily defined paths. In your infancy, connections between neurons are easily formed and dropped, and as you age neurons which receive no activity begin to go dormant as formed pathways are strengthened. This makes learning more difficult, but certainly not impossible.

The issue with this theory is brain plasticity. It is well-documented that some people who have received a traumatic event and suffered brain damage as a result can re-learn forgotten abilities, sometimes even in places of the brain which are not specialized for that task. I do not know if we know whether this activates formerly dormant neurons, or if existing neurons simply take up more tasks.

Also, it is well known that myelin sheaths, which protect neuron shafts, degrade over time. A thicker myelin sheath provides a less lossy pathway for the electrical component of neuron activity. As the sheath degrades, the neuron may not be able to fire enough to reach the next in the chain, so information can be lost along the way. Thinking can become foggier and slower, which of course would hinder learning.

But that’s just what I think I know as a neurobiology hobbyist 🙂

Myelin sheath strength correlates directly with the speed at which neurons can ‘communicate’ and ‘receive communication’ to/from each other through their dendrites and axons. This can weaken as one ages. However, I think the most important aspect about this question is in regards to how quickly we can learn in our youth (i.e. ‘kids’ brains are like sponges’) because we are continuing to grown synaptic connections at an extremely rapid rate. However, once you enter your mid-twenties or so, your synaptic connections begin to start ‘pruning’ which is cutting out the unnecessary connections. This does not mean that you can’t learn new things as you age, however. Just think of everything you learned through school, and then consider what you can remember now (assuming you are past your mid-twenties). Memorization and forging new synaptic connections does become more challenging if you are not constantly learning. This is why life-long learning is of the utmost importance.