What is Dematerialized consciousness?
REH From: futurework-boun...@lists.uwaterloo.ca [mailto:futurework-boun...@lists.uwaterloo.ca] On Behalf Of Steve Kurtz Sent: Monday, September 16, 2013 5:40 AM To: Futurework list Subject: [Futurework] Researchers measure consciousness through brain activity Dematerialized consciousness takes another hit. Steve http://www.world-science.net/othernews/130814_consciousness <http://www.world-science.net/> "Long before it's in the papers" August 14, 2013 RETURN TO THE WORLD SCIENCE HOME PAGE <http://www.world-science.net/> _____ Researchers measure consciousness through brain activity Aug. 14, 2013 Courtesy of Science Translational Medicine and <http://www.world-science.net/> World Science staff A new study seems to back up pre-vi-ous pro-pos-als that the lev-el of com-plex-ity of your brain ac-ti-vity largely de-ter-mines wheth-er you're con-scious or not. Sci-en-tists de-vel-oped a test of con-sciousness based on the con-cept-a test that does-n't re-quire a pa-tient to ac-tu-ally do an-y-thing, they said. Con-scious-ness is elu-sive, but we know it's what van-ishes when we fall in-to a deep sleep and reap-pears when we wake up. Doc-tors typ-ic-ally de-ter-mine if a per-son is con-scious by their abil-ity to pro-cess and re-spond to ex-ter-nal com-mands, such as "open your eyes" or "squeeze my hand." But these meth-ods are su-per-fi-cial, as re-search has shown in the last dec-ade that a brain to-tally dis-con-nect-ed from the out-side world may still have some aware-ness. This may hap-pen in brain-injured pa-tients who emerge from a co-ma but can't move or un-der-stand in-struc-tions, for ex-am-ple. One the-o-ry is that in a con-scious brain, dif-fer-ent popula-t-ions of neu-rons, or nerve cells, car-ry out their own com-puta-t-ional roles, but can't com-mu-ni-cate with oth-er neu-ron popula-t-ions. When the brain loses com-plex-ity, some sci-ent-ists pro-pose, neu-rons ei-ther start to be-have more si-m-i-larly al-to-geth-er (re-sult-ing in a loss of in-forma-t-ion), or their abil-ity to com-mu-ni-cate is im-paired (re-sult-ing in a loss of in-tegra-t-ion). For ex-am-ple, if you're asleep and you hear a dog bark-ing, your brain will re-spond with ac-ti-vity in the au-di-to-ry cor-tex, the part of the brain that pro-cesses sound. But if you're awake, the same sound might al-so in-duce thoughts of your own dog, or an-noy-ance at the loud-ness of the bark-re-sponses tied to ac-ti-vity in the brain's mem-o-ry and emo-tion cen-ters. These lat-er brain pro-cesses con-tain more in-forma-t-ion. Neu-ro-sci-en-tists have been try-ing to de-vel-op ways to meas-ure con-sciousness based on this brain com-plex-ity. In the stu-dy, Mar-cel-lo Mass-mini of the Uni-vers-ity of Mi-lan in Italy and col-leagues de-vised a tech-nique to meas-ure this brain com-plex-ity, or how much in-tegra-t-ion and in-forma-t-ion flow is hap-pening in the brain. Called the Per-turba-t-ional Com-plex-ity In-dex or PCI, their tech-nique in-volves mildly "shak-ing" the whole brain with a strong mag-net-ic stimula-t-ion and re-cord-ing the re-sponse of neu-rons. This da-ta can then be used to cal-cu-late how much in-forma-t-ion the brain is able to pro-duce as a whole. The re-search-ers tested the tech-nique in pa-tients with brain in-ju-ries, pa-tients un-der an-es-the-sia with dif-fer-ent drugs, and in pa-tients who were awake, in deep sleep or dream-ing. The test re-flected the par-ti-ci-pants' lev-el of con-sciousness un-der each of these con-di-tions, they found. The re-sults sug-gest that dif-fer-ent lev-els of con-sciousness are tightly linked to the com-plex-ity of the brain re-sponse, they added. For ex-am-ple, find-ing a "PCI val-ue" above the sleep or an-es-the-sia lev-el in a pa-tient who is oth-erwise un-re-spon-sive would sug-gest she or he is con-scious to some ex-tent. Al-though more re-search is needed, the anal-y-sis could po-ten-tially be a use-ful tool at the hos-pi-tal bed-side for meas-ur-ing con-sciousness, they added. The find-ings are pub-lished in the Aug. 14 is-sue of the jour-nal Sci-ence Transla-t-ional Med-i-cine. * * * Send us a comment on this story, or send it to a friend <mailto:?Body=http://www.world-science.net/othernews/130814_consciousness.ht m>
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