Brain Cramp Meaning

Example : 1944, D. H. Lawrence and Frieda Lawrence, The First Lady Chatterley (original version of Lady Chatterley's Lover, 2005 reprint), ISBN 9781419130595, ch. 20, p. 264:  "I can't remember. I've got a cramp of the brain. Do you mind hitting me over the head?"  "What for?"  "To make me forget the last two minutes, and take away my brain cramp."1991 Nov. 3, Robert Lipsyte, "Sports: Backtalk—Imaginations Running Wild Through the City," New York Times (retrieved 30 Nov 2011):  Don't think too fast at the start. You can get a brain cramp, which is how marathon ruminations are lost.2009, Stephen King, Under the Dome, ISBN 9781439149034, online preview edition:  I had a brain-cramp there for a minute, the smile said, but now sanity has reasserted itself.2011 Nov. 18, Kent Ward, "Thankful for things to be thankful for," Bangor Daily News (USA) (retrieved 30 Nov 2011):  Republican presidential hopeful Rick Perry suffered through a cringe-inducing brain cramp during a recent prime-time television debate and was unable to name the third agency of government that he, as president, would eliminate.