Chapter 4 | Senses, Meet Brain

Summary

How do the matter and energy of sensation interact with out bodies? And, how do our sensory organs, and the cells and proteins they consist of, detect this stuff of sensation. How would you go about making the senses better, and what are their physical limits? We also look at the impossibility of using temperature to sense remote object, as seen on the Daredevil television show.

Chapter Excerpt: “We spent the last couple of chapters focusing on what sorts of stimuli are available for us to sense, and how they interact with our sensory organs through dedicated sensory receptors endowed with specialized protein micro-machinery. This first step, during which a proximal stimulus is detected and converted into a chemically mediated electrical signal, is called transduction. The signal, or neural impulse, which travels along the nerve fiber to the brain, is called the action potential and is at once one of the most banal and fascinating phenomena in nature.
The action potential is common to all the senses – all neural activity, in fact – regardless of which sensory pathway gave rise to it. Nothing about the nature of the particular stimulus from the outside world is preserved in this spike of activity. In fact, the action potential is so basic that we can liken it to a kind of morse code, but instead of having short pulses and long pulses, there is just one sort of pulse. The action potential is all or nothing. A more intense stimulus causes more signals to be sent, and through more nerve fibers, but the magnitude of the individual spike doesn’t change.”