In elementary school, we learn about the five senses and their vital importance to appreciating life. Taste, smell, touch, hearing, and vision are all vital to survival, and even with the absence of one or more, our bodies compensate by strengthening the senses we do have. But what about using our senses in a more advanced setting, like mind reading?
That idea was addressed in “Sense and Sensibilities,” a Brain Awareness Week webinar last Tuesday by students at the University of California San Diego (UCSD). They took turns explaining the mechanisms behind our senses and explored the extraordinary ways in which our touch, hearing, and vision can be used.
Speaker Margot Wohl, a graduate student, diagramed the way sound travels to the brain. It vibrates in the ear drum, hits the small bones within the ear, and then moves into the cochlea (a small spiral portion of the ear). The cochlea is covered in small “hair cells,” that move with the vibrations and, in turn, interprets them as nerve impulses. Scientists can read what the brain hears by using a decoder machine that relays the frequency of sound-wave vibrations.
This leads to the question of whether internal thoughts could be read by the same decoder, Wohl said. If people are hearing their thoughts, why wouldn’t the sound waves in the brain be the same as an audible sound? It turns out that it is somewhat possible, but the results are inconsistent.
Saumya Gupta, an undergraduate, spoke about sense of touch, but not in the way most people perceive it. Proprioception, she explained, is the sense of your body’s position in space. We use this sense in all aspects of our lives, from the ability to walk without looking at our feet to typing without looking at a keyboard. Proprioceptors will monitor the length, tension and pressure of our muscles, tendons, and joints. They will relay signals about our body’s position to the brain, which, in turn, provide us with body orientation.
However, proprioception can go wrong, Gupta explained. In the case of amputated limbs, people will falsely send brain signal to the amputated area, and cause the “phantom limb” syndrome. Gupta called it “proprioceptive memory,” when the brain retains a memory of specific limb positioning. Dr. V.S. Ramachandran, a professor at UCSD, created “mirror box therapy” for patients suffering from phantom limb. The mirror box would reflect the healthy limb to the other extremity, tricking the brain into thinking that the amputated limb was getting signals. Over time, with the therapy, the brain would stop sending stimuli to the amputated limb to try and move it.
To hear the full webinar, click here.