The New York Times mentioned the mammalian diving reflex in an article about David Blain last Tuesday. In humans, it allows you to hold your breath longer when under water, by slowing the heart and lowering blood flow to your extremities. Aquatic mammals have a more intense version of this reflex, and when diving deep into the ocean, they reflexively pass blood through their chest cavity to stop their organs from being crushed by the pressure.

In humans, this reflex is started when water sensitive receptors in the face activate cranial nerve V (trigemenal). The trigeminal signals the brain and then cranial nerve X (vagus).

Cranial nerves are nerves directly connected to your brain: olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, audito-vestibular, glossopharyngeal, vagus, spinal accessory, and hypoglossol. (Additionally there is a controversial cranial nerve 0 which recent studies suggest may be associated with pheromones.)

My neuropsych textbook included the mnemonic “On Old Olympia’s Tottering Top A French And German Viewed Some Hops.”

Wikipedia also includes the more lude (and therefore maybe easier to memorize): Oh, Ohh, Oh, To Touch And Feel Virgin Girls’ Vaginas And Hymens. Note with this second mnemonic it calls the eleventh nerve just the accessory nerve instead of the spinal accessory nerve.

Another immature mnemonic is listed to help memorize the types of information they carry (where s is for sensory, m is for motor, and b is for both): Some Say Money Matters, But My Brother Says Big Boobs Matter More. Both the nerves discussed earlier in this post (V the Trigeminal and X the Vagus) carry both sensory and motor information.

Wikipedia’s full list contains many mnemonic gems like: OLd OPie OCcasionally TRies TRIGonometry And Feels VEry GLOomy, VAGUe, And HYPOactive.

Only On Occasion, Touching The Amorous Female Virgin Goat Vacillates A Hand

You have 1 nose, 2 eyes, and 3,4,6 make your eyes do tricks!

Only April 30th, David Blain will go on Oprah and attempt to break the world record for holding one’s breath after breathing pure oxygen of 16 minutes and 14 seconds.  A feat impossible without the mammillian diving reflex.