The enig­mas that live in­side your head

The Weekend Australian - Review - - Books -

It’s a ques­tion that has plagued philoso­phers for cen­turies: what ex­actly is con­scious­ness?

Anaes­thetists — the peo­ple whose job it is to take con­scious­ness away from us — tend not to worry about it so much.

You might think that’s be­cause they’re prac­ti­cal peo­ple, fo­cused on the job at hand rather than more ab­struse philo­soph­i­cal ques­tions. But it may be be­cause they ac­tu­ally have no idea how to an­swer the ques­tion.

The as­ton­ish­ing thing is that, while we know (more or less) that anaes­the­sia works, we don’t re­ally know how or even ex­actly what it does.

In­spired partly by her own fear of sur­ren­der­ing to the moon­less night of anaes­the­sia, Mel­bourne jour­nal­ist Kate Cole-Adams has spent more than a decade in­ves­ti­gat­ing the prac­tice she calls “the most bril­liant and baf­fling gift of mod­ern medicine”. The re­sult­ing book, Anaes­the­sia, is not just an ac­count of med­i­cal re­search but a po­etic ex­plo­ration of the mys­ter­ies of the hu­man mind.

Ev­ery day, anaes­thetists put hun­dreds of thou­sands of peo­ple into chem­i­cal co­mas, ColeA­dams writes, al­low­ing “the body’s de­fences to be breached in ways pre­vi­ously un­imag­in­able ex­cept dur­ing war­fare or other catas­tro­phe”. Through the use of pow­er­ful poi­sons, [anaes­the­sia] has en­abled en­try into the se­cret cav­i­ties of the chest and the belly and the brain. It has freed sur­geons to saw like car­pen­ters through the bony fortress of the ribs. It has made it pos­si­ble for a doc­tor to hold in her hand a steadily beat­ing heart.

It is, as Cole-Adams says, mind-blow­ing. And yet, just how our minds get blown away, and then brought back again, re­mains a mys­tery even to those who per­form this ma­noeu­vre on a daily ba­sis.

Although she is at pains to as­sert that mod­ern anaes­the­sia is re­mark­ably safe, Cole-Adams does not ap­pear par­tic­u­larly re­as­sured by the re­sponse of some anaes­thetists to her ques­tions about how the whole thing ac­tu­ally works: you don’t need to un­der­stand how an en­gine works to drive a car.

Mod­ern gen­eral anaes­the­sia re­lies on a cock­tail of mind-al­ter­ing drugs, which act in dif­fer­ent, not al­ways pre­dictable, ways on dif­fer­ent parts of the brain. The three main el­e­ments of the cock­tail are gen­er­ally: hyp­notics to cre­ate and main­tain un­con­scious­ness; anal­gesics to con­trol pain; and a mus­cle re­lax­ant to stop the pa­tient mov­ing on the op­er­at­ing ta­ble.

“Dif­fer­ent anaes­thetists mix up dif­fer­ent cock­tails,” Cole-Adams ex­plains. “Each has a favourite recipe. An olive or a twist. There is no stan­dard dose.”

Hyp­notics are pow­er­ful drugs and, at higher doses, lethal ones. “In blot­ting out con­scious­ness, they can sup­press not only the senses but also the car­dio­vas­cu­lar sys­tem. Ev­ery time you have a gen­eral anaes­thetic, you take a trip to­wards death and back.”

Most of us do, of course, make it safely back but, given the im­pre­ci­sion of the sci­ence, it’s not sur­pris­ing anaes­the­sia doesn’t al­ways go ac­cord­ing to plan.

Cole-Adams speaks to peo­ple who have ex­pe­ri­enced “anaes­thetic aware­ness”, the or­deal of be­ing con­scious dur­ing surgery but, due to the pres­ence of a mus­cle re­lax­ant in the anaes­thetic cock­tail, un­able to sig­nal that aware­ness to op­er­at­ing the­atre staff. Pa­tients can be left trau­ma­tised, haunted by mem­o­ries of pain ac­com­pa­nied by ut­ter paral­y­sis.

For­tu­nately, such ex­pe­ri­ences are rare … as far as we know. Hyp­notic drugs are also pow­er­ful am­ne­si­acs, rais­ing ques­tions about whether anaes­thetic aware­ness may be more com­mon than we re­alise, but rarely re­mem­bered once we emerge from our in­duced coma.

Even if we do re­main un­con­scious through­out the pro­ce­dure, could trauma at some level re­main im­printed on us, Cole-Adams won­ders, and how might that af­fect us in the life af­ter anaes­the­sia? Might we ex­pe­ri­ence on­go­ing emo­tional “mem­o­ries” with­out con­sciously un­der­stand­ing their source?

Bri­tish neu­ro­sur­geon Henry Marsh is an­other writer who has grap­pled with the mys­tery of con­scious­ness, and its op­po­site, in his case from the per­spec­tive of some­one who has spent his life cut­ting into liv­ing hu­man brains.

“There are one hun­dred bil­lion nerve cells in our brains,” he wrote in his bestselling first mem­oir, Do No Harm. “Does each one have a frag­ment of con­scious­ness within it? How many nerve cells do we re­quire to be con­scious or to feel pain? Or does con­scious­ness and thought re­side in the elec­tro­chem­i­cal im­pulses that join these bil­lions of cells to­gether?’’

Car­di­nal George Pell is un­der in­tense pres­sure; fac­ing page, Pell in Rome dur­ing the royal com­mis­sion

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