Single-neuron encoding of rapidly learned visual information reshapes human perception.

Humans can swiftly learn to recognize visual objects after minimal exposure. Integrating new information with existing knowledge requires forming enduring neuronal representations to enable future recognition. Yet, the neuronal mechanisms in the human brain underlying such rapid perceptual changes remain unclear. We recorded single-neuron activity in occipital (OC) and medial temporal lobe (MTL) regions as participants rapidly learned to recognize degraded images. OC and MTL neurons modulated their activity to encode newly learned visual information and reshape perception. Population decoding revealed that OC neurons required additional processing time to resolve the identity of learned images, delaying neuronal responses in the MTL. Our findings indicate that OC supports recognition after rapid learning via extensive recurrent processing, potentially involving higher-order neocortical areas, without relying on feedback from MTL. These results provide mechanistic constraints for biologically plausible models of visual recognition and few-shot visual learning.