CYBCYL Chapter 3- Love and Depression: The Deep Limbic System

This chapter delves into the role of the “deep limbic system” in our daily lives. However, it should be clarified that this term should not be confused with “limbic system”, which has other additional parts. Rather the “deep limbic system” in this chapter refers to the thalamic structures and hypothalamus, along with other surrounding systems.

The limbic system can be considered the “older” and more “primal” part of the brain. It has enabled animals to experience and show emotions, and the deep limbic system has many other functions including:

•  setting the emotional tone of the mind
• filtering external events through internal states (emotional coloring) 
• “tagging” events as internally important
• Storing highly charged emotional memories
• Modulating motivation
• Controlling appetite and sleep cycles
• Directly processing the sense of smell
• Promoting bonding
• Modulating libido

The chapter showed that in SPECT scans, brains that were more overactive in the deep limbic system area were correlated with subjects’ depression and negativity. This may be counterintuitive as once thought. What this means is that when the deep limbic system is overexcited, our perspective of the outside world changes (in this case, we become more pessimistic). More is discussed in this chapter relating to the menstrual cycle in females and the associated change in behavior. The deep limbic system is also responsible for directly processing the sense of smell as well as modulating libido. What this means is that certain smells may increase sexual arousal and activity (which has been proven in tests).

This chapter is very significant towards my understanding of human behavior. I did not know how or why certain people were pessimists and others were optimists. I did not know why emotional memories could change a person’s perspective. I did not know why sexual activity was associated with smells or why it decreased stress. However, this chapter answers all those questions.

The deep limbic system is one of the most important parts of our brains, especially in determining human behavior. It was very interesting to read about how all these functions were linked in some way, and I have seen that the key to understanding comes from knowing the key functions of the deep limbic system. For instance, the deep limbic system is responsible for both modulating libido and promoting bonding. This is important to understand because it means that many teenagers who embark in casual sexual relationships may become more attached to one another. I hope to use the information I learned in this chapter to form links where other parts of the brain are discussed (in future chapters).