Predictive coding (PC) hypothesizes that the brain computes internal models of predicted events and that unpredicted stimuli are signaled with prediction errors that feed forward. We tested this hypothesis using a visual oddball task. A repetitive sequence interrupted by a novel stimulus is a “local” oddball. “Global” oddballs defy predictions while repeating the local context, thereby dissociating genuine prediction errors from adaptation-related responses. We recorded neuronal spiking activity across the visual hierarchy in mice and monkeys viewing these oddballs. Local oddball responses largely followed PC: they were robust, emerged early in layers 2/3, and fed forward. Global oddball responses challenged PC: they were weak, absent in most visual areas, more robust in prefrontal cortex, emerged in non-granular layers, and did not involve inhibitory interneurons relaying predictive suppression. Contrary to PC, genuine predictive coding does not emerge early in sensory processing, and is instead exclusive to more cognitive, higher-order areas.
The Surgery team offers a variety of aseptic rodent surgical procedures ranging from stereotaxic injections to headpost implantation and cranial windowing.
The Neuropixels platform uses pioneering technology for highly reproducible, targeted, brain-wide, cell-type-specific electrophysiology to record neural activity from defined neuron types across the brain.
The Molecular Anatomy platform combines innovative histology, imaging, and analysis techniques to map the morphology and molecular identity of neuron types across the whole brain.
The Behavior platform uses advanced technology to implement a standardized, modular, multi-task virtual reality gymnasium for mice, with the goal to study brain function across different behaviors at scale.
The Fiber Photometry platform enables optical measurement of neural activity in live animals to study neural circuits' function and dynamics in behaving animals.