Chapter 4 The Petrifaction Spell
Enlightened by Ratchet, Charity decided to write something in the Daily Prophet. But before she came up with an outline, the agreement time was drawing near, so she apparated to the place they met.
A yellow Hummer 2's arrival made the witch delight. The car transformed and asked happily, "What spell are you going to perform today?"
"The patrifaction spell."
Charity took out a nervous cat under her cloak. She caressed its back, and ensured that it would be rewarded after the performance. Then she pointed her wand to the cat and said, "Petrificus totallus!" The spell was very effective, because the cat's flexible body was stiff now. Its limbs were unbendable, its head and tail rose high as if fixed by an invisible hand, and it could even stand on the ground like a small statue.
"Oh, can you remove the curse from that poor cat?"
"Yeah, yes, of course…" Then she removed the curse. The cat looked at Charity petiously, but turned cheerful quickly, because Charity took out some fish.
"Well, I think that was similar to decerebrate rigidity."
"What is that then?"
"If the nerve between hypothalamus and epithalamus was cut off, then the cerebral cortex can't inhibit the muscle's tonic. That's why the name is 'decerebrate'."
"Then my cat was petrified?"
"Not enough, another reason is that there exists more facilitatory area than inhibitory area in the brain stem reticular formation. When that part of nerve was cut off, the muscle was controlled by more facilitatory area-Hey, are you sleepy?"
"Wha-at?"
"I think you were absentee-minded just now."
"How did you know?" Charity asked curiously. If she could master this, then it would be quite easy to supervise the students.
"I found that your EEG, I mean, Electroencephalogram, which shows the spontaneous electricity activity of your cerebral cortex, had changed. Well, when you are thinking, your EEG wave is β-wave. But it turns to θ-wave, when people get sleepy."
"Wow, so amusing!"
"But did you understand my explaination of decerebrate rigidity?"
"Er, a little hard for me. But I do know that the muscle is controlled by both cereball, er, cerebral cortex and brain stem reti-reticular formation. The cerebral cortex helps muscle ease more, and the brain stem reticular formation helps muscle tense more. Am I correct?"
"Good! You've got it."
"Can muggles, well, I mean normal people, make it?"
"Yes, they can. But they don't know how to make those animals restore, because the nerve in central nerve system can't regrow after cutting off."
"Poor animals. I'm glad that we can restore them." Charity's cat snored at her feet satisfiedly.
About decerebrate rigidity: go to Wikipedia for further information… ( ^_^ )
PS: People often use cats on their research. I really want to put a picture of a cat with decerebrate rigidity here, but it seems that even giving a link is impossible, so just google it if you are interested.