Blog Post 1
Throughout my childhood my parents, teachers, and even social media have always been there nagging us and making sure we eat a good breakfast before going on about our days. There are many areas of the brain involved with appetite and hunger although our eating habits could also have had an association with those habits of our ancestors. Food in general is a necessity to live therefore I can imagine that getting enough food is very important to staying as healthy as possible. What would cause us to eat as soon as we wake up whether we are hungry or not. Although there is no single area of the brain responsible for sensing and responding to food, the areas of the brain associated with the desire and regulation of hunger were the hypothalamus, the orbitofrontal cortex, and the amygdala (Freberg, 2010). Although there is no single area of the brain responsible for sensing and responding to food, the areas of the brain associated with the desire and regulation of hunger were the hypothalamus, the orbitofrontal cortex, and the amygdala. The area I found to be most closely related to hunger was the hypothalamus. The hypothalamus is a major regulatory center for hunger, thirst, sexual behavior and aggression (Freberg, 2010). There are two areas in the hypothalamus that control hunger. The part of the hypothalamus that causes you to feel hungry when stimulated is the lateral hypothalamus. If you were to lesion the lateral hypothalamus, you would have a lack of hunger if any at all. The second part, the ventromedial hypothalamus gives you that full feeling when stimulated. Unlike the lateral hypothalamus, a lesion to the ventromedial hypothalamus would give the patient a complete lack of the fullness sensation (Valenstein, et al., 1970). Recent research has also shown us that the orbitofrontal cortex is involved with detection of how pleasant or good food tastes to us and the amygdala controls the wanting and desire for food (Felsted, et al., 2010). This observation may play an important role in understanding the decision making involved in our choice to eat breakfast and what we include in that meal. (Green & Nachtigal, 2010).
There are also three types of receptors on the tongue with sensory connections in the cortex. They are the thermoreceptors (sense temperature), mechanoreceptors (touch or texture), and nociceptors, (sense pain). These receptors are responsible for detecting qualities or characteristics of food (taste, smell, temperature, texture, and spicy/sweet). The flavor of the food is then compounded by the cortex where the brain fuses together the senses from these receptors. Research has shown that connected areas of the brain then determine the intensity of the desire for that flavor and the degrees of hunger (Green & Nachtigal, 2010).
The primary method used to determine the interconnectivity of the brain areas that also show the components of flavor when eating is by the use of functional magnetic resonance imaging (fMRI) Shown by a study conducted by D. M. Small world and K. Rudenga (2010). In this study liquids containing a potentially nutritious substance (sugar) as well as a potential “toxin”, capsaicin were fed to (16) subjects. Capsaicin is a compound that once in contact with any tissue will cause a burning sensation. The reason they chose to use the capsaicin is because it has been shown to activate the thermoreceptors and nocireceptors that I noted earlier in this blog post, detect temperature and pain. Studies have shown that the same part of the cortex responds to other basic tastes as well. These researchers have discovered that there are “different” connections based on the significance of the taste. Good foods activate one set of connections, while what is perceived as a toxic food activates another part of the brain (Rudenga & Small, 2010) Taste alone however can’t determine whether a person chooses to continue or stop eating. The results of this study showed that those who had eaten the potentially nutritious stimulus had greater connectivity than that of the capsaicin between the anterior ventral insula and the hypothalamus therefore showing a connection with eating certain foods over others. For example choosing sugary cereal over bitter fruits in the morning. (Rudenga & small, 2010)
Overall, the decision making process involved with whether or not we eat in the morning and what we eat can be attributed to certain areas of the brain. I do however believe the decision to eat breakfast in the morning before worrying about the rest of our day could be a survival instinct, and could help influence what foods we eat based on what types of foods kept those in prehistoric times alive long enough to reproduce and carry on such traits or “tastes”. It’s possible that they consumed meats from animals they hunted to survive so it could impact our decision to have steak or sausage for breakfast but then again maybe those eggs you had for breakfast last week gave you gas so you chose to avoid them and went with the cereal instead which in turn has sugars that your body perceives as “good”.
Freberg, L.A. (2010). Discovering Biological Psychology (2nd edition). New York, NY: Wadsworth Cengage Learning.
Valenstein, Elliot S.; Cox, Verne C.; Kakolewski, Jan W., (1970) Reexamination of the Role of the Hypothalamus in Motivation. Psychological Review, Vol 77
K. Rudenga, B. Green, D. Nachtigal, D. M. Small (2010) “Evidence for an Integrated Oral Sensory Module in the Human Anterior Ventral Insula.” Chemical Senses.
J. Felsted, F. Chouinard-Decorte, X Ren, D. M. Small (2010) “Genetically Determined Brain Response to a Primary Food Reward.” Journal of Neuroscience