Chapter 5 (Days to Months Before) begins by reminding us of the focus of the previous chapters, Seconds being the nervous system, Minutes to Hours being sensory cues, and Hours to Days being hormones. This chapter focuses on memory. Memory comes from the connection between the axon terminal and the dendritic spine. You would think new memory means new connections between these two, but it is rather a strengthening bond between the two which creates new memories. Putting it in the simplest terms I could follow, this happens in this way because of receptors on the dendritic spine. The spine contains one receptor, called the non-NMDA receptor. The axon releases glutamate, which causes an excitement. This excitement can only be detected by NMDA receptors. So how does the brain know to get excited about something if the spine only has non-NMDA receptors? After a length of time the axon will have released a lot of glutamate, this release will activate the NMDA receptor so that the dendritic spine becomes aware of the excitement. Lots of excitement over a long period of time leads to the NMDA receptors being more open in the future. This is how we remember. There is a lot more to it, but after reading through this section many times, this is how I came to understand the process. I then read an interesting piece about compensation. It is a common saying or belief that if you lose one of your senses the others will grow stronger, and there is proof of this being valid. The brain knows how to utilize areas of the brain that are not being used, say the visual area in the brain of a person who is blind, to improve the hearing area of the blind individual. Additionally, the visual area of the brain becomes activated when a blind person reads in Braille. Reading pieces like this make me want to learn more about compensation.
Chapter 6 (Adolescence; or, Dude, Where’s My Frontal Cortex?) did not interest me all that much. I learned that the teen years are the years when we take the most risks and are most interested in things that are unique and different, and this is because the prefrontal cortex is not fully developed and won’t be until we reach our mid-twenties. This also attributes to the reason why we are the most violent when we are teens and young adults, because we are less sensitive to pain, less sensitive to negative feedback (I like to think of it as the “I don’t care” attitude), and there isn’t a strong connection between moral reasoning and empathy. Why is there a delay in the prefrontal cortex? You’ll just need to read this chapter to hear some of the theories.
Nonfiction and Nonsense 