Specific expertise from diffuse feedback: A feedforward-gated mechanism.

Neuronal enhancements during perceptual learning are widespread and confined to feedback-influenced responses, supporting a hierarchical, bidirectional learning mechanism in macaque V4.

• Why it matters: Understanding how perceptual learning improves sensitivity without losing stimulus specificity addresses a key challenge in sensory neuroscience, balancing stability and plasticity in the brain.
• What they did: Researchers recorded neuronal populations in macaque visual area V4 during a contour detection task, revealing that neural improvements occurred broadly across neurons but were gated by feature-specific feedforward inputs.
• The result: Findings suggest that learning enhances higher-order representations that broadly modulate early sensory neurons through feedback, enabling perceptual expertise to develop without compromising sensory stability.