PoA Question -- Sirius & Dementors

[joywitch999]

Original Yahoo! HPFG Header:
No: HPFGUIDX C5703
From: joywitch999
Subject: Re: PoA Question -- Sirius & Dementors
Reply To: [Yahoo! #5682] Re: PoA Question -- Sirius & Dementors
Date: 8/4/00 12:26 pm  (ET)

<<<Did the stress of running into the Dementors somehow cause him to
transform back into his human form? He was clearly less vulnerable
(by far) to the Dementors as a dog.>>>

<Perhaps it has something to do with the change in brain function elicited
by the Dementors; the fact that they create something akin to clinical
depression and drain away positive thoughts.>

<For an animagus, switching between forms must involve major emotional
input, and certain parts of the brain (such as the hippocampus) would
control that. The same areas of the brain would be affected by the
soul-sucking of the dementors to the extent that, ultimately, Sirius
would have been unable to retain his animal form.>

But then how did Sirius manage to spend so much time as a dog while in
Azkaban, surrounded by dementors?