Week 7

This week was a short week because it is fall break. We only had three days of class this week but due to Tuesday taking on the Thursday class schedule we were able to have lab on Tuesday and this weeks exam is a take-home exam so we could have lecture on Wednesday still and get a full three lecture week in on somatosensation. Also it is important to note that Eric gave us a chance to demonstrate our understanding of what was discussed in lab on Tuesday and those of us who were able to regurgitate enough information are exempt from taking this week’s take-home exam. Eric is an absolute “O.G. Homie” for that!

Somatosensation can most simply be described in laymen terms as the sense of “feeling”. This includes but is not limited to the sense of touch. The sense of touch is what monitors our interface with the environment. Thus, as a general rule, anything that has greater interface with the environment has higher sensitivity to touch. This means body parts like hands, feet, lips, and external genitalia have a higher sensitivity to being touched than an earlobe or a kneecap. If you want a real-life example of this you can do an activity we did in the first day of lecture if you have a partner to do it with. All you need is two pointed objects (we used nails) and a ruler or measuring device of some sort. Have one person take the two pointed objects and apply pressure on a body part of the other person in close proximity to each other. The person who owns the body part must be looking away for this to work. If they are close enough together it will feel like one object is touching you. The objective is to keep doing this while increasing the distance between the two objects ever so slightly each time until it is perceived as two objects touching you rather than one. Now measure the distance and repeat with a different body part. It was kind of fun to see what was most sensitive on my body. For my partner and I the lips were the most sensitive followed by fingers and palms. Our ankles were not very sensitive.

As I said before the sense of “touch” is not the only somatosense we have. The somatosenses include cutaneous senses (what I was talking about before as the sense of “touch”), proprioception which is sensory information about your body location and orientation in space, kinesthesia which is sensory information about how your body is moving in space, and finally organic senses which is information coming from in and around internal organs. All of these senses are similar in that explaining any of them likely involves using the word “feel” to describe it but they each serve a very distinct purpose and have different anatomical structures to help produce them.