Summer SAVY, Session 4 Day 3, “Intro to Neurobiology” (5th-6th)
Our first topic of the day was Sensation and Perception, one of the four key functions of the central nervous system (the brain and the spinal cord). We began by making a distinction between sensation and perception. The terms sounded abstract, so we did it using a very fun class activity, which many students volunteered to participate in. The activity involved a student wearing an eye mask and holding a book in each of his/her hands. The books were identical. Then, a tiny piece of paper was added on top of a book, and the student was asked if he/she felt like the weights were the same or different on the two hands. To their surprise, students’ perception of the weight did not match reality. When they said their left hand felt a heavier weight, the extra weight was actually added to the right hand. It turned out that although our body may be able to “sense” the additional weight, the weight increase was so small that it could not be “perceived” accurately. Our students were able to better understand the differences between sensation and perception after this activity.
We moved on to more examples of sensation vs. perception and stimuli vs. perception. The goal is to realize that perception is subjective and is just the brain’s interpretation of electrical signals from stimuli (changes in the environment or in our body). For example, sugar water is a stimulus, but sweetness is a perception. Injury is a stimulus, and pain is a perception. Then we got into an even more interesting sub-topic: Does light have colors? Actually, it may not. Colors are just lights of different wavelengths, and our nervous system/brain reacts to different wavelengths by generating different feelings. Our students evaluated the famous picture of “the dress”. Some people perceive the color of the dress as white and gold, but blue, while others see it as black. We also saw other optical illusions, such as a square looking like it’s bent in concentric circles. All these cases helped us understand the subjectivity of perception.
In the afternoon, we went back to our memory topic. Our students first had a review by sharing their understanding of key memory concepts and corresponding examples. Then we picked up where we left off yesterday – implicit/unconscious memory. After that, we moved on to explicit/conscious memory, consisting of semantic and episodic memory. We began with semantic memory, which is not only facts stored in our brain, but also the logical relations between these facts. Our students had a first-hand experience accessing their semantic memory of answering a few trivia questions, such as “Who first discovered gravity?”. Then, to understand the “logical relations” between facts, our students participated in a seemingly mysterious activity. They listened to a paragraph from Harry Potter and were told to remember the meaning of the paragraph. It was suggested they not take notes during the listening. Then, 2 minutes after listening to the paragraph, our students were invited to reproduce the paragraph on paper, trying to use the exact words from the audio clip but also encouraged to use their own words if they couldn’t remember the exact ones. It turned out that many, if not all, of our students activated the “logical relations” in their semantic memory. Specifically, they were able to use words that did not come up at all in the original text but had similar meanings to words in the original text, such as “nothing happened” for “hardly anything” and “video game” for “computer game”. It shows that our students had those logical relations (synonyms) stored in their brains all along and successfully retrieved (found and used) them!
We then moved on to another type of semantic memory – episodic memory. It refers to events that happened to us and involves not only perceptual memory and typically numerous vivid details, but also a sense of self in it. We read some examples together, but the most fun part of it was that each of us shared our very first childhood memories. All students shared and listened attentively to their peers as they shared stories of their first memories. Then we went to a computer lab to work on a group project designed to help students understand the underlying neurobiological structure of memory better. We have four groups in the class, and each of them was assigned one of the topics: 1. The case of Patient “H.M.” (a famous amnesic patient who contributed tremendously to the research of the brain, especially the region responsible for memory); 2. The case of Clive Wearing (also an amnesic patient), 3. Definition, symptoms, and causes of Alzheimer’s disease; and 4. Treatment of Alzheimer’s disease.
Our students will present their group projects first thing tomorrow morning!