Is the Brain a Useful Model for Artificial Intelligence?

Is the Brain a Useful Model for Artificial(ˌärdəˈfiSHəl) Intelligence(inˈteləjəns)?

Thinking machines think just like us—but only up to a point.

By Kelly Clancy

In the summer of 2009, the Israeli(izˈrālē) neuroscientist(ˈn(y)o͝orōˌsīəntəst) Henry Markram strode(strōd) onto the TED stage in Oxford(ˈäksfərd), England, and made an immodest(i(m)ˈmädəst) proposal(prəˈpōzəl): Within a decade, he said, he and his colleagues would build a complete simulation(ˌsimyəˈlāSH(ə)n) of the human brain inside a supercomputer. They’d already spent years mapping the cells in the neocortex(ˌnēōˈkôrteks), the supposed seat(sēt) of thought and perception(pərˈsepSH(ə)n). “It’s a bit like going and cataloging(ˈkadlˌôɡ) a piece of the rain forest,” Markram explained. “How many trees does it have? What shapes are the trees?” Now his team would create a virtual rain forest in silicon, from which they hoped artificial intelligence would organically(ôrˈɡanək(ə)lē) emerge(əˈmərj). If all went well, he quipped(kwip), perhaps the simulated brain would give a follow-up TED talk, beamed(bēm) in by hologram(ˈhäləˌɡram).

Markram’s idea—that we might grasp the nature of biological intelligence by mimicking(ˈmimik) its forms—was rooted in a long tradition, dating back to the work of the Spanish anatomist(əˈnadəməst) and Nobel(nōˈbel) laureate(ˈlôrēət) Santiago(ˌsan(t)ēˈäɡō) Ramón y Cajal(kə’). In the late 19th century, Cajal undertook a microscopic(ˌmīkrəˈskäpik) study of the brain, which he compared to a forest so dense(dens) that “the trunks, branches, and leaves touch everywhere.” By sketching thousands of neurons(ˈn(y)o͝orän) in exquisite(ekˈskwizət) detail, Cajal was able to infer an astonishing(əˈstänəSHiNG) amount about how they worked. He saw that they were effectively one-way input-output devices: They received electrochemical(əˌlektrōˈkeməkəl) messages in treelike structures called dendrites(ˈdendrīt) and passed them along through slender(ˈslendər) tubes(t(y)o͞ob) called axons(ˈakˌsän), much like “the junctions of electric conductors(kənˈdəktər).”

Cajal’s way of looking at neurons became the lens through which scientists studied brain function. It also inspired major technological(ˌteknəˈläjək(ə)l) advances.