Memory Formation, Storage, and Retrieval

Memory Formation, Storage, And Retrieval

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The role of memory is quite important in retrieving that which was learned. This being the case, it is wise to explore how memory works so that we can exploit what is currently known about this process to promote learning, to make it easier, and to make it more efficient. One definition of memory is that it is “… the reactivation of a specific group of neurons, formed from persistent changes in the strength of connections between neurons” (The University of Queensland, 2018, para. 2). This begs the question’ How does this happen? The mechanism is termed synaptic plasticity (The University of Queensland, 2018). A synapse is a space between an axon and a dendrite. Upon stimulation, this space becomes flooded with a neurotransmitter that passes the electrical impulse over the gap (synapse) between the transmitting nerve cell to the receiving nerve cell. An increase or decrease in strength is determined by how often these synapses are activated. For example, imagine a grassy lawn. As people walk across this lawn in the same direction, a pathway is worn into the grass. This is like repetitive activity along a neuron, through a synapse, and on to another neuron and another synapse until the impulse reaches its destination. The more this path is used, the stronger the pathway. Yet, synaptic plasticity is perhaps not the only element contributing to the formation of memories. Neurogenesis (the birth of new nerve cells) also affects memory formation. This neurogenesis occurs in the hippocampus. There is some evidence that mice's memory can be improved by increasing neurogenesis. Vigorous physical exercise by humans increases neurogenesis, thereby, likely affecting memory.

Memories form an interconnected assembly of neurons, much like a matrix. This interconnection of neurons is a function of synaptic plasticity. This leads to the realization that memory does not reside in a single location. For example, recall a scene from childhood. Imagine a Sunday afternoon walk with a parent, On one of these walks, they found a hummingbird nest. It was a beautiful and wonderfully made nest of soft fibers. It contained three eggs. That memory resides in not one place but in several. There are the visual images of the nest, the tree branch, the woods, the mellow sunlight filtering through the trees Then, there are sounds associated with the event: the gentle wind whispering through the trees, the sound of the birds, the distant sound of water flowing in the river. There is also a memory of feeling the breeze pass over one’s arms, the fresh smell of the forest, the coolness associated with the river. As you can see, this memory involves more than one sense. The various sense memories are stored in different locations in the brain. It is thought that our marvelous brain coordinates the assembly of these sensations and synchronizes them to complete the entire memory.

Emotions play an important role in our memories. Intense emotions like fear or love help memory formation and significance. The University of Queensland Brain Institute (2018) observes that “This happens because of the amygdala, which brain imaging studies have shown is activated by emotional events. …this boosts memory encoding…by triggering the release of stress hormones, such as adrenaline and cortisol, to boost arousal” (para. 3). Too intense an emotion can have the opposite effect by invoking a more rigid stimulus-response association (The University of Queensland Brain Institute (2018).

Neuroplasticity

Neuroplasticity, According to The Shiel (n.d.) website, is