Theoretical Representation Lab Report

Cortical Representation Laboratory
Introduction
The body uses different tools to understand the outside world and to orientate itself in the world. Using a variety of sensory organs, the brain creates a representational picture of the body. This representational picture is used in two ways by the brain’s parietal lobe: motor and somatosensory (Myers and DeWall, 2018, p. 75-78). In the somatosensory part of the parietal cortex, the brain uses the representational picture of the body to interpret where a touch occurs (Myers and DeWall, 2018, p. 78). When a finger is tapped by a toothpick, a certain area of the brain activates to register that touch. However, not ever point of the body is equally represented in the brain. Some parts of the body
Participants randomly chose an order for touching the digits, received a toothpick, and performed two coin tosses to decide with which side of the body (left or right) and with which appendage (hand or foot) to start. After the decision to start with a one appendage, the second person in the pair performed the opposite side starting with the opposite appendage. In other words, if the coin toss results determined the first participant to start with the right hand, then the second participant would start with the left foot. The participants first experienced a test touch on each digit before the official testing began. The fingers were numbered 1 through 5 with the thumb as #1 and the pinkie as #5. The toes were also numbered 1 through 5 with the big toe as #1 and the little toe as #5. The participants responded after each touch with the number of the digit they thought was touched. No feedback was given on the participants’ accuracy during the
We were able to support our hypothesis: the toes are less sensitive than the fingers and have less distinct representation in the parietal lobe of the brain. Since the participants were less able to distinguish touches to the foot than touches to the hand, we can conclude that the hand is more sensitive than the foot. We can also see that certain toes are more distinctly represented in the brain than others. The big toe and the little toe seem to be distinct in the parietal lobe because the first graph shows more correct responses to these digits. The 2nd, 3rd, and 4th toes seem to overlap in the parietal lobe because the participants most often confused the touches to these toes. Overall, this experiment provides a better understanding of the fingers and toes’ representation in the brain’s somatosensory