Study finds brain begins decisions in sensory regions, challenging hierarchy model

Researchers at the University of Illinois Urbana-Champaign have found evidence that decision-making begins in primary sensory brain regions much earlier than previously thought, challenging the long-held view that decisions emerge only after information passes through a strict hierarchy of brain areas. The study, published in Proceedings of the National Academy of Sciences, shows that higher brain areas influence sensory regions through rapid feedback loops rather than one-way forward processing. Led by electrical and computer engineering professor Yurii Vlasov at the Grainger College of Engineering, the work suggests the brain operates as a dynamic system with continuous bidirectional signaling. The findings could inform the design of more capable and energy-efficient AI systems that mimic biological processing. Reverse-engineering the brain was identified by the National Academy of Engineering in 2008 as one of the 14 grand challenges for engineering in the 21st century.