The hypothesis is that more interconnectedness enables stronger feedback loops, which, according to Olshausen, are probably how the brain achieves “perceptual filling in,” where higher layers make inferences about what lower layers are sensing based on partial information. “That’s intimately connected to consciousness,” he said.
The human brain, of course, remains much more complicated than any of the models; it is larger, denser, more efficient, more interconnected, has more complex neurons — and juggles several algorithms simultaneously. Olshausen has estimated that we understand only 15 percent of the activity in the visual cortex. Although the models are making progress, neuroscience is still “a bit like physics before Newton,” he said. Still, he is confident that the process of building on these algorithms may one day explain the ultimate riddle of the brain — how sensory data gets transformed into a subjective awareness of reality. Consciousness, Olshausen said, “is something that emerges out of a really, really complicated Boltzmann machine.”
Reprinted with permission from Quanta Magazine, an editorially independent division of SimonsFoundation.org whose mission is to enhance public understanding of science by covering research developments and trends in mathematics and the physical and life sciences.