Hypersounds breaking your brain.  Sorry.  
 
Official Discussion on http://www.reddit.com/r/CGPGrey/comments/1tjaj4/the_video_will_hurt_grey_explains/
 
 
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Special Thanks to:
 
http://www.youtube.com/user/TotalPhilosophy/
 
Saylor Fielder
 
Julian Yap
 
Ardalan Moazeni
 
Dr Clifton K. Meader  http://goo.gl/DpsuGk
 
Dr Fabrizio Benedetti
 
Max Ramsay - @maxafax, The Soden Family, Conan Kudo (ニール・ゴンパ), Kira Lanier, Lisa Marie Terry, Dave Roberts (the Best Dad ever), mikey.reiach.net, Carine Frsch, Mauceri76, David Benko, Team Fluger, A.Manning, Smuffie00, Robert English, @jwvdiermen, Laura Saura Maura Watiker, Nicholas Hartikainen, M Go Blue!, @chrisaiello, @Bad1z, Kuffer Sam
 
Selected sources:
 
http://bjp.rcpsych.org/content/180/4/300.full
 
211.144.68.84:9998/91keshi/Public/File/39/16-11/pdf/nm.2229.pdf
 
http://www.bmj.com/content/332/7546/886?view=long&pmid=16520326
 
http://www.ncbi.nlm.nih.gov/pubmed/22336767
 
http://www.researchgate.net/publication/40819426_Nocebo-induced_hyperalgesia_during_local_anesthetic_injection/file/72e7e5203d9229e4c5.pdf
 
http://www.sciencedirect.com/science/article/pii/S0022399912003352
 
http://jama.jamanetwork.com/data/Journals/JAMA/4983/JOC50054.pdf
 
http://ses.library.usyd.edu.au/handle/2123/8977
 
http://www.bmj.com/content/339/bmj.b5613
 
http://www.ncbi.nlm.nih.gov/m/pubmed/21627976/
 
http://www.nejm.org/doi/full/10.1056/NEJM200001133420206