Guru Magazine - - In The News -

Not only do your neu­rons know what you’re go­ing to do be­fore you do, but neu­ro­sci­en­tists now think they might even be able to al­ter your de­ci­sions be­fore you are aware of hav­ing made them. Adding fuel to the age-old de­bate about whether we truly have free will, Gabriel Kreiman of Har­vard Med­i­cal School told at­ten­dees at the fes­ti­val that he is find­ing out more about how our will, or ‘vo­li­tion’, is con­trolled within the brain. Kreiman and his col­leagues have pre­vi­ously shown that mon­i­tor­ing the brain ac­tiv­ity of peo­ple asked to per­form a sim­ple phys­i­cal task en­ables the sci­en­tists to pre­dict when par­tic­i­pants are go­ing to move be­fore they be­come aware of de­cid­ing to act. In th­ese stud­ies, they had ac­cess to epilepsy pa­tients who had elec­trodes im­planted to help

lo­cate where their seizures started from. Us­ing th­ese sen­sors, Kreiman and col­leagues were able to record the ac­tiv­ity of over 1,000 brain cells in two ar­eas known as the frontal and tem­po­ral lobes (at the front and side of the head). Putting the pa­tients in front of a com­puter, they asked them to click the mouse and re­mem­ber the read­ing on a clock when­ever they de­cided to. Be­fore mov­ing their hand – and just be­fore the pa­tients were aware of de­cid­ing to click – groups of brain cells grad­u­ally in­creased their ac­tiv­ity. Th­ese ‘get­ting ready’ signals were seen in brain re­gions be­lieved to be re­spon­si­ble for pre­par­ing move­ments (the sup­ple­men­tary mo­tor area), and one of the brain’s re­ward and at­ten­tion ar­eas (the an­te­rior cin­gu­late cor­tex). In an­other ex­per­i­ment they were able to pre­dict which hand peo­ple chose to use. Th­ese rather mys­te­ri­ous re­sults tally with a

sim­i­lar ex­per­i­ment that used brain imag­ing and found de­ci­sions could be pre­dicted as much as ten sec­onds be­fore con­scious aware­ness. The sci­en­tist be­hind that work also pre­sented find­ings at the fes­ti­val, which showed that we can now pre­dict ab­stract de­ci­sions, such as whether to add or

sub­tract. Kreiman be­lieves th­ese re­sults may mean that neu­rons’ ac­tiv­ity builds up un­til a thresh­old is reached, when the de­ci­sion en­ters aware­ness and an ac­tion is taken. He is now work­ing out ways to watch this in real time to find out whether it is pos­si­ble to change a de­ci­sion be­fore it is acted on and also whether there is a ‘point of no re­turn’. He cau­tioned: “We’re not say­ing we can make pre­dic­tions about what you’re go­ing to have for lunch to­mor­row or who you’re go­ing to marry in five years – we’re mak­ing very spe­cific small claims about a very sim­ple de­ci­sion.” But he then added: “Our ac­tions and will are to­tally dic­tated by ensem­bles of neu­rons (brain cells) and the prob­lem of free will can ul­ti­mately be un­der­stood as the fir­ing of neu­rons.”


Gabriel Kreiman at the posttalk press con­fer­ence.

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