The Biology of Learning

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and science writer for Lumos Labs.

The field of neuroscience is just beginning to understand some of the physiological foundations of how we learn. The following is a basic breakdown of what we think we might know.

Learning is the process by which new knowledge or skills sticks to our brains.  Its functional “sticky” unit is the neuron. Neurons are cells specially adapted to communicate with each other. Everything we experience is reflected in the brain by neurons which communicate to form what are called neural networks.  These networks can be pictured as overlapping 3-D road maps which span brain regions responsible for processing everything from the bitter-sweet taste of dark chocolate to why your neighbor is such a grump. As we learn, these neural “road maps” interact and shift while also fading or strengthening in relation to our experiences.

Whether it be recognizing a co-worker or changing a flat tire, learning entails the formation and strengthening of connections or synapses between neurons. Brief experiences typically leave connections tracing an ephemeral neural network. This might be envisioned as crisscrossing deer paths. Which, if left unused, fade quickly.

After repeated exposure to a learning experience, like the second time we change that flat tire, the associated neuronal connections are reinforced, resembling more a network of single lane country roads than deer paths.  And when it comes to daily practice and expertise in a skill, one can imagine that the guy at the local tire shop would have the neuronal equivalent of intersecting super-highways.

This strengthening of neural network connections is thought to be the physiological basis of learning.

Changing, strengthening and creating new neural networks tends to get more difficult with age. There is some research, however, indicating that it is possible to maintain our ability to learn, and possibly even ward off or lessen the impact of certain types of dementia. It appears that a significant amount of age related cognitive decline can be attributed to a tendency to stay within pre-established comfort zones; shying away from new and challenging experiences, which typically push the brain to grow (or at least not shrink as fast).

Here are some simple tips that could help maintain our brain’s ability to adapt.

• Stay Social- Reaching out and staying connected with friends and family engages the mind.

• Break a Sweat- It’s not only good for your body but your head as well.  Regular aerobic exercise is even capable of stimulating the formation of new neurons.

• Relax- Certain stress hormones are damaging to the brain in excess.

• Seek Challenges- Take that swing dance class, it’ll keep you on your toes in more ways than one. Do a variety of the Lumosity brain games – don’t just focus on your favorites.

• Eat Fruits and Veggies- You’ve heard it a million times before; this time it’s because they contain anti-oxidants and other substances protective of your head’s contents.

• Review Your Day- Take some evening time to review what you did, who you met, and what you read about. Start with the present and work your way back to breakfast or vice a versa.

Long-term and Working Memory – You Are What You Remember

By Gregory Kellett,  a cognitive neuroscience researcher at SFSU and UCSF and science writer for Lumos Labs.

Memories are vital to our ability to function on even the most basic of levels. Our respective “realities” are in fact a large part due to the constantly shifting kaleidoscope of our remembrances. Here we will touch briefly on the difference between short-term/working memory and long-term memory as well as how the two filter and add meaning to our worlds.

What if we could remember everything we experienced? As enticing as it sounds, our finite brains would quickly find themselves overwhelmed with the random details of yesterday’s weather forecast alongside the nutritional information off of last month’s box of raisin bran.

Thankfully, the vast majority of our memories are fleeting mental wisps lasting only seconds to minutes. These temporary impressions make up what is called short-term or working memory.

Working memory can be thought of as a staging area where the mind takes meaning from such items as:

• Specific immediate memories of very recent sensory input (IE the sour smell of expired milk).
• The temporary recollection of details from long-term memories (IE what happened the last time you drank sour milk).
• Conclusions and ideas made in the past (Sour milk is bad).

Notice how working memory can temporarily pull details from long-term memory for short-term use. Although constantly changing and ephemeral itself, working memory is vital to our ability to make decisions and take action over time (such as our pouring that sour milk down the drain). For a brilliant and more in-depth description of working memory read Elizabeth Buchen’s “Working Memory: What it is and how it works”.

When an experience or piece of information sticks and doesn’t evaporate with short-term memory, it is said to have entered into the realm of long-term memory. This journey is called consolidation and takes place after prolonged exposure to a piece of information or experience. The longer the exposure, the better the consolidation, the more robust the related memories will be.

Long-term memories can store much larger quantities of information than working memory and for much longer periods of time (often as much as a lifetime). These resilient long-term recollections are made up of both consciously learned facts, such as “Madrid is the capital of Spain” and subconsciously learned knowledge, such as the ability to balance and ride a bike.

We derive meaning and the ability to act via the synergistic relationship between long-term and working memory. Working memory combines elements from our long-term stores with immediate sensory information in order to generate ideas and plans of action. For example, remembering that the taste of peanut butter is pleasant as we toast toast, might just have us use our memorized skill of unscrewing a jar in order to manifest the pleasurable experience of peanut butter on toast. Which is just one more potentially delicious result of a fit and active mind.

Good Cholesterol and Good Memory

By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF, and writer for Lumos Labs.

A recent British study published by the American Heart Association suggests that the balance of cholesterol in our blood may affect not only heart health but also memory performance. It is widely accepted that diets promoting “Good” cholesterol, otherwise known as high-density lipoprotiens (HDL), can reduce cardiovascular disease, but it now appears that high HDL may also be good for memory.

Researchers tested 3,600 British civil servants for both HDL levels and memory performance over time, first at an average age of 55 and then again at 61.

The results?

• Participants with higher HDL levels did consistently better at recalling items from a list of 20 words after 2 minutes.
• For those whose HDL levels declined between tests there were also declines in memory performance.

Reference:

Singh-Manoux, A., Gimeno, D., Kivimaki, M., Brunner, E., & Marmot, M. G. (2008). Low HDL Cholesterol Is a Risk Factor for Deficit and Decline in Memory in Midlife. The Whitehall II Study. Arterioscler Thromb Vasc Biol, 28, 1398.