Neuroplasticity and Memory
“The human brain is a learning machine. Thanks to a phenomenon called neuroplasticity, the brain learns in a range of ways and many different circumstances, including in the classroom.” (Pankaj Sah, Queensland Brain Institute, n.d.).
Neuroplasticity is central to learning. It is essential to remember that learning is a function of memory encoding and consolidation, which, in turn, are processes that change the brain physically.
We refer to the brain as being ‘plastic’, because it can change at the cellular level (mostly at the connections between neurons i.e. the synaptic gaps) by creating and reinforcing neural networks. The brain discards, retains and changes information in response to new and repeated experiences.
We learn through repetition. McTighe and Willis (2019) cite the example of learning to tie our shoelaces:
“For example, when children learn to tie their shoes, they repeatedly practise the steps. In so doing, the associated neurons repeatedly activate in sequence, strengthening the circuit of connected neurons each time. Practice results in the establishment of a ‘shoe-tying’ network … Through neuroplasticity, the brain is molded by experience to reshape and reorganize itself so that we awake with a ‘new’ brain each morning!” (pp.12-13).
Whether implicitly or explicitly, neuroplasticity must be a central concept when we think about or discuss learning and memory.
Stages of memory
McLeod (2013) suggests that there are three recognised stages of memory development. These are:
Encoding: Memories can be encoded visually (picture), acoustically (sound) or semantically (meaning). Acoustic encoding, as an example, has been found to be effective for short-term memory (STM). Semantic encoding appears to be the principle encoding system for long-term memory (LTM).
Storage: There is a difference in the way we store STM and LTM. We do know that if we ‘chunk’ information together, we can store a lot more in our STM.
Retrieval: Data becomes a memory if we can retrieve it. Our STM and LTM retrieval is very different – STM are stored and retrieved sequentially, while LTM is retrieved by association.
It is important to note that one of the issues with memory research is that it is often conducted by experiment. This means that some question the low ‘ecological validity’ of memory experiments, which means their findings cannot be generalised. While these findings are a little older, the general view around memory does remain consistent. Understanding these stages can assist educators in thinking about how to help students learn.
When cells interact…
Neurologically, memories are formed when experience is encoded through patterns, whereby cells interact with each other. Almost 20 years ago, scientists at the University of California discovered that brain cells could form connections, temporary and permanent, in response to stimuli. This was the first evidence that the brain could change structurally, influencing how we store and retrieve memory. This discovery proved what scientists had suspected for some time. The important discovery also noted the link between the stimulation of cells, and the creation of a memory.
The researchers found that actin (a protein) inside cells could be stimulated to move toward neurons to which they are connected. Activity in the first cell prompted movement of actin in neighbouring neurons. This temporary movement is quite normal, and the activation would last up five minutes, and then disappear quickly. However, they found that if the original cell was stimulated repeatedly (in this case, four times) within an hour, the synapse would physically split, producing new synapses. This potentially produces a permanent change. (University of California, San Diego, 2001). The key finding here is that we can induce or consolidate memory through repetition or exposure to experience. We also know that new memories can be quite unstable, but become more ‘consolidated’ over time. This occurs physiologically, through an interaction between glutamate release, protein synthesis, and neuron growth and rearrangement’ (‘The role of consolidation in memory’).
The role of consolidation in memory. About Memory. http://www.memory-key.com/memory/consolidation
McLeod, S. A. (2013, August 05). Stages of memory - encoding storage and retrieval. Simply Psychology. https://www.simplypsychology.org/memory.html
University of California, San Diego. (2001). Media Release - Pictures reveal how nerve cells form connections to store short- and long-term memories in brain. Retrieved from: https://ucsdnews.ucsd.edu/archive/newsrel/science/mccell.htm