Study: Brain Decisions Start in Sensory Cortex
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- Yurii Vlasov and University of Illinois researchers published a study in PNAS showing decision-related activity in the primary somatosensory cortex (S1), one of the brain's earliest sensory processing areas.
- The team recorded neural activity in mice navigating a virtual reality corridor and found that S1 was influenced by higher brain regions through rapid feedback loops, suggesting bidirectional communication rather than one-way information flow.
- The findings challenge the traditional hierarchical model that has inspired convolutional neural networks and shaped decades of AI architecture.
- Vlasov said the goal is to "learn from a billion years of evolution" to design AI that is "more effective, less power hungry, and more intelligent" by emulating the brain's feedback-loop architecture.
- Next steps include studying the fast temporal dynamics of these brain signals and developing new technologies for measuring how feedback loops coordinate different levels of brain processing.
- The journal publication credits Alex G. Armstrong and Yurii Vlasov as authors of "Neural correlates of perceptual decision-making in the primary somatosensory cortex," PNAS 2026; 123 (18).
Why it matters: The study upends the textbook model that sensory cortex is a passive relay, finding instead that primary somatosensory cortex participates in decisions via top-down feedback loops — a systems-level insight Vlasov says could guide next-generation AI that matches biological intelligence's energy efficiency. Reverse-engineering the brain was named one of the National Academy of Engineering's 14 grand challenges for the 21st century.
