A Little Brain Science
Our brains are remarkable organs that operate on chemical-electrical responses to sensory stimuli (sight, hearing, touch, taste, smell, movement or proprioception) in our environment. Various parts of the brain assume responsibility for specific functions, and each part of the brain connects and communicates with the other parts of the brain in very complex ways. When we are born, these areas are not fully defined or developed, and it is our experiences in the earliest years that help shape how well each area of the brain responds.
Recent research has shown us much about the plasticity of the brain. We know, for example, that when one part of the brain is damaged, the brain often re-wires around the damage. We also know that when a specific sensory pathway is impaired or absent, for example vision, that area of the brain normally used to process visual information may start to process other sensory information such as touch.
The Limbic System
Deep inside the brain are a group of structures referred to as the limbic system. Though there is some disagreement about what exactly makes up the limbic system, there are four critical components we need to learn about when thinking about a learner’s appetites and aversions. These include: Hypothalamus, Amygdala, Thalamus and Hippocampus. (Emotions: limbic system | Processing the Environment | MCAT | Khan Academy, 2013)
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The thalamus functions as a sort of relay station for sensory information coming into the brain from various sensory organs feeding into the limbic system. The only sense that does not come through the thalamus is smell. Smell comes through another organ located nearer to the amygdala and hypothalamus. This is why smell often evokes a great and lasting emotional response.
The hypothalamus is located above the pituitary gland and sends it chemical messages that control the pituitary function. It regulates body temperature, synchronizes sleep patterns, controls hunger and thirst and also plays a role in some aspects of memory and emotion.
Small, almond-shaped structures, the amygdalae are located under each half (hemisphere) of the brain. Included in the limbic system, the amygdalae regulate emotion and memory and are associated with the brain’s reward system, stress, and the “fight or flight” response when someone perceives a threat.
A curved seahorse-shaped organ on the underside of each temporal lobe, the hippocampus is part of a larger structure called the hippocampal formation. It supports memory, learning, navigation and perception of space. It receives information from the cerebral cortex.
Parietal Lobe and Somatosensory Cortex
The somatosensory cortex is a region of the brain in the parietal lobe which is responsible for receiving and processing sensory information from across the body, such as touch, temperature, and pain. Sensations from receptors positioned throughout the body that are responsible for detecting touch, proprioception (i.e. the position of the body in space), pain, and temperature. When receptors detect one of these sensations, the information is sent first to the thalamus and then to the primary somatosensory cortex. (2-minute Neuroscience: primary somatosensory cortex, 2022)
The parietal lobe is a part of the brain located behind the frontal cortex and above the temporal cortex. The parietal lobe integrates sensory information among various modalities, including proprioception. It is the main sensory receptive area for the sense of touch in the somatosensory cortex which includes inputs from the skin (touch, temperature, and pain receptors) and internal receptors located in the muscles and joints (proprioceptive sensors). Sensory information relays through the thalamus to the parietal lobe.
The parietal lobe also plays a role in a person’s ability to judge size, shape, and distance. Additionally, it helps with the interpretation of symbols including those in written and spoken language, mathematical problems, and codes and puzzles. Hearing and visual perception, as well as memory, are also part of the parietal lobe’s functions. (Medical News Today, 2020)
This area of the brain allocates different amount of brain space to processing information from various regions of the body. For example, information from the head (eyes, ears, nose, mouth, tongue) take up a great deal of brain matter and information from the arm takes up very little. There is a funny image called the homunculus that describes this.
The prefrontal cortex is similar to a control center, helping to guide our actions, and plays a role in emotion regulation. If you saw the animated movie, Inside Out, you got the idea that someone had to be in charge of regulating all the various emotions we experience as humans.
As humans mature our brain typically develops the ability to regulate our response to sensory information so that we can calm ourselves down or rouse ourselves to attend and wake-up. Children are not born with this ability, but rather develop it over time. They are, in fact, developing and refining this ability well into their early twenties. This is why parents learn ways to calm a crying baby or rock them to sleep when they are overly tired and stressed. The infant and even the toddler may have a very hard time coming back to a calm alert or active alert on their own.
Children with significant developmental challenges, such as deafblindness and multiple disabilities especially related to their sensory systems, may be unable to do this even as adults. They may always need support from others. If we intervene and utilize strategies that address the individual’s emotional development, as well as cognitive development, the child may learn better how to do this on their own.
Sympathetic and Parasympathetic Nervous System
Other features of our bodies that play a part in regulating our states are the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS) (The Autonomic Nervous System: Sympathetic and Parasympathetic Divisions). The sympathetic nervous system causes changes in your body that are associated with “fight or flight” and prepare your body to move or take action. It is tied to functions primarily in the left hemisphere of the brain and triggered by the amygdala and thalamus. For example, if you see what you think is a snake, your body might do these things: heart beats faster, breath faster, pupils dilate, mouth goes dry, your body produces more glucose for energy, and you might run or strike out at the snake. The SNS in other words, does everything it can to keep you safe, and it will try to get you away from or address danger. Other functions of the brain lose importance while this is going on, so this makes for a less than ideal state for learning new information or having dinner.
“Fight or flight” refers to an automatic physiological reaction to an event that is perceived as stressful or frightening. The perception of threat activates the sympathetic nervous system and triggers an acute stress response. The threat doesn’t have to be real; we just need to perceive it as a threat. This is what we refer to when we talk about “aversions”. When we look at interactions and programming for children who are deafblind and who may also have additional challenges, we want to avoid things that trigger this response.
The parasympathetic nervous system causes changes in your body that are associated with things that let you “rest and digest”. So back to the snake example, if you look again where you thought you saw a snake and realize that the what you saw was only a stick, your parasympathetic system returns you to your base state where respiration, heart rate, and lung function return to normal. Your pupils constrict, you are able to produce more saliva, and you are once again able to expend the energy to digest food. The PNS is tied to functions primarily in the right hemisphere of the brain. Like fight or flight, when we are fully in rest and digest mode, we are usually in a state, maybe daydreaming or even asleep. These states are also not conducive to learning.
We want to avoid activities and environments that cause the learner to move into “rest and digest” mode during instruction. Instead we want to help the child move into a calm alert or active alert state, where they are able to engage fully in learning. These states are more conducive to engaging in interactions and participating actively in independent learning. Our challenge as educators is to develop learning activities and environments that cause the child to alert, become curious, and seek to engage with the person, object, or environment. We refer to sensory experiences that help the child achieve these states “appetites”.
Sympathetic Versus Parasympathetic Nervous System Responses
Sympathetic Nervous System Responses
- Increases heart rate and dilation of coronary blood vessels for increased blood flow and availability of oxygen and energy to the heart
- Dilation of blood vessels serving muscles increases oxygen to skeletal muscles and brain
Increased respiration rate and availability of oxygen in blood
- Increases glucose in skeletal muscle and brain cells
- Skin pales or flushs as blood flow is redirected to muscles
- Dilation of the pupils to improve visual acuity to scan nearby surroundings
Parasympathetic Nervous System Responses
- Pupils constrict to improve your close-up vision and causes tear production
- Production of saliva and mucus to aid digestion and breathing during times of rest
- Tightens airway muscles to reduce the amount of work your lungs do
- Lowers your heart rate and the pumping force of the heart
- Increases your rate of digestion and diverts energy to help you digest food
- Signals pancreas to make and release insulin
- Relaxes the muscles that control when you pee or poop
- Manages some of your body’s sexual functions