The Colliculi

Modified: 2024-06-02 11:36 PM CDST

• The inferior and superior colliculi together comprise the colliculi.
  • The inferior colliculus (here, inferior mean further from the front) is responsible for reflexive responses to auditory stimuli.
  • If I were to surprise you with a loud noise, you would look up.
  • That response of looking up is controlled by the inferior colliculus.
  • Note that we can sometimes prevent such responses from occurring, while sitting in a deer stand, for example. We may prevent ourselves fromlooking when we hear the sounds of twigs cracking.

• The superior colliculus, the next bump anterior (closer to the front of the brain) to the inferior colliculus, serves a similar function, but now the stimuli are visual.
  • When you turn quickly to see something, some movement you detected out of the corner of your eye, for instance, it is your superior colliculus that makes you do that.
  • An interesting example involving the superior colliculus is the design of B-52 bomber cockpits. B-52 pilots practice takeoffs with heavy curtains drawn over the windows of the bomber.
  • They do this because the light from a nuclear explosion is so bright that should a nuclear bomb explode near them while they were taking off, they would not be able to prevent themselves from looking at it.
  • The light is so bright that it would burn out their retinas, blinding them.
  • So, the curtains prevent that from happening.
• Another science fiction example comes from a Star Trek episode.
• Spock is temporarily blinded by McCoy.
  • Vulcans had evolved on a planet where one of the suns flared on occasion.
  • So, vulcans possessed a nictitating membrane that reflexively covered their eyes when a bright light flashed.
  • Bet you did not think you would also learn Vulcan physiology too! (This part is NOT on any tests :-)