Schaefer, J. August, 2020

Neuroscience of learning

Neurons are one of the cell types that make up the brain (in addition to other cells called “glial cells”). In order to understand how specific strategies create optimal learning, it is important to understand the following fundamental aspects of brain function.

1) Neurons make connections with each other a specialized meeting points, or junctions, called synapses. 2) At synapses, information is sent in the form of chemical messengers, called neurotransmitters, that are released from upstream neurons and received by downstream neurons. 3) Groups of neurons or brain regions that are interconnected and participate in the same task or behavior are called neural circuits or neural networks. 4) Synapse connections between neurons can strengthen and weaken based on previous activity and experience (referred to as synaptic plasticity). 5) New synapses can be generated—this is called synaptogenesis--and old synapses can be removed based on previous activity and experience (another form of Owens and Tanner, 2017. CBE-Life Sci Educ. 16:fe2, 1-9 synaptic plasticity). 6) Learning and involve a few phases (below). Successful completion of each phase requires synapses to be activated. a. Encoding: the initial formation of a memory that may still be retained or lost b. Storage: maintaining a memory over time (long term memory) c. Retrieval: accessing stored when needed d. Consolidation: this term is used to refer to stabilization of memory—you can think of it as transitioning from encoding to storage for the purposes of this document. 7) Memory formation and storage requires synaptic plasticity (strengthening, weakening, change in synapse number). Memory retrieval is an opportunity for further synaptic plasticity and “recoding” of the memory. 8) The hippocampus is an important location in the brain for memory encoding. Memories are moved from the hippocampus to other locations in the brain for memory storage. The hippocampus also plays a role in memory retrieval.

Brief explanations of the neuroscience behind a few selected learning strategies are found on the following pages, in no particular order.

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Schaefer, J. August, 2020

Strategy: Sleep • The brain “clears space” in the hippocampus during sleep, allowing the hippocampus to better encode new memories the next day. • There are three phases of sleep: rapid-eye movement (REM); light non-REM (light NREM); deep non-REM (deep NREM or slow wave sleep). A typical night’s sleep cycles between these phases in a fairly predictable manner. • Sleep is important for moving memories from encoding (short term) to storage (long term). It appears that the brain stores factual, language, and motor skill memories during deep NREM or slow wave sleep (along with repairing damage to the body). The brain stores procedural or process-type memories during REM sleep. • Importantly, the brain connects new memories to previous memories during REM sleep. • Memory storage during sleep requires a full sleep cycle in order to get sufficient durations of all three sleep phases, so we need a full night of sleep (not short intervals) for optimal learning and memory. Further, hormones involved in helping us fall asleep and stay asleep are best released in the dark, so sleeping during dark night hours is most effective. (It also help to block blue light emitted from screens prior to sleep.) • Afternoon naps also increase memory consolidation at the hippocampus, but are not sufficient alone—you still need a good night’s sleep. 20 minute naps or 90 minute naps are best. 60 minute naps are problematic, leaving you sleepy and sluggish, because they interrupt the sleep cycle mid-phase.

Strategy: Exercise • Blood flow increases during aerobic exercise. This blood flow increases mental alertness, synaptogenesis, and neurogenesis (birth of new neurons) in the hippocampus. • Exercise helps to maintain levels of stress and stress hormones (such as cortisol) below problematic levels so they do not interfere with brain function--particularly in the hippocampus. • Specific neurotransmitters released during exercise increase synaptic plasticity.

Strategy: • Distributed practice (“spread out” practice, not one long study session) is required for learning. Repeated, frequent activation of synapses within neural circuits is required to generate the synaptic plasticity needed for memory encoding and storage. • Memories are lost over time as synapses weaken, disappear, and are replaced by new memories (synaptic plasticity). The act of recalling a memory or learned information (memory retrieval) reduces the rate at which that memory is forgotten or lost.

Strategy: Connect to prior knowledge and interests • Emotionally charged memories are most likely to be stored and retrieved, and to be stored/retrieved over a long period of time. Connect new material to your interests and passions or to emotionally charged memories that you already have. Also, attend to your emotions while you learn. Find ways to start with positive mindset and emotions. • The brain is very good at storing patterns and at connecting new memories to existing memories (see “sleep” above). Take time to examine the connections between new material and previous material so that your brain can complete an easier task (adding on to existing memories) rather than a more difficult task (forming entirely new memories). Similarly, take

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Schaefer, J. August, 2020

time to identify patterns in the material you are learning. Example patterns include: timelines, cause/effect, hierarchies of importance, and textbook section heading layout.

Strategy: Avoid distractions and multitasking • Our brains are extremely bad at multitasking. Brains learn best when they can maintain attention on one task at a time. • Task switching requires the following steps: 1) alert brain that attention needs to shift, 2) close down current task, 3) activate attention to new task. We have to do this each time we shift between tasks. It takes brain resources to do this and those resources are then not available for learning tasks or formation of new memories. In addition, task shifting increases the probability of mental errors.

Strategy: Retrieval practice and testing effect • Retrieval practice is a strategy in which you put away all materials and cues about what you are learning and then try to the material on blank piece of paper. This gives your brain a chance to practice memory retrieval of the relevant information. Memory retrieval allows for additional synaptic plasticity that can further strengthen the memory (but it also allows for recoding of inaccurate memories—so be careful to double-check your work!). • The testing effect says that we learn material better when we are tested on it (either self- quizzing or class quizzes/tests). The moderate stress created by testing releases a small amount of stress hormones. In small amounts, the hormones increase mental alertness and performance.

Strategy: Generate diagrams/concept maps/drawings to practice material • Dual coding of memories, or coding a memory in multiple forms (for example, both visual + text form), enhances memory encoding. • Associations between memories helps with later memory retrieval because it creates multiple “paths” by which the brain can access the stored memory. • Creating new ways to represent and evaluate information is a form of active learning. Lower levels of learning, such as , are associated with the hippocampus. Higher-level learning processes such as creating, analyzing, and applying, require coordinated activity between more widespread regions of the brain. More complex thought processes are beneficial for learning because they activate a greater number of synapses and more cross-talk between neurons and neural networks outside of the hippocampus. Activity across more synapses and networks will strengthen more synapses, which is required for learning and memory.

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