[Verse 1] Deep in visual cortex where the neurons fire and glow Feedback signals streaming from the regions up above Like a dimmer switch adjusting what the lower layers show Attention turns the volume up on features that we love Moran and Desimone discovered how the gain gets turned When focus hits V4, those neurons bright and clear While LIP creates a priority map that's finely tuned Steering early processing to what we need to hear [Chorus] Feedback's flowing downward like a river made of thought Predictions, gain, and context mixing everything we've got The brain's not just receiving, it's predicting what will be Error signals climbing up the visual hierarchy Top-down meets bottom-up in this neural symphony That's how we see the world through feedback's mystery [Verse 2] Your classical receptive field's just part of the whole tale Surround suppression kicks in from regions far away An edge responds differently when context tips the scale Figure-ground and border ownership change throughout the day Extra-classical influence from feedback connections wide The same local feature gets a different neural vote Depending on the global scene that's painted all around Long-range lateral circuits help the story that it wrote [Chorus] Feedback's flowing downward like a river made of thought Predictions, gain, and context mixing everything we've got The brain's not just receiving, it's predicting what will be Error signals climbing up the visual hierarchy Top-down meets bottom-up in this neural symphony That's how we see the world through feedback's mystery [Verse 3] Rao and Ballard had a vision back in ninety-nine Predictive coding theory turned the whole field on its head Higher areas send predictions down the processing line Lower regions compute the error, send surprises up instead When prediction matches input, then the error signal fades Expected edges get explained away and responses shrink End-stopping and suppression fall in place like puzzle pieces The iterative dance continues faster than you think [Bridge] Perception is construction, not a passive camera's view The brain's best explanation of the sensory array Hierarchical Bayesian frameworks try to see it through Friston's free energy principle maps the broader way From visual cortex outward to the whole brain's grand design Though theory runs ahead of what the data can confirm [Final Chorus] Feedback's flowing downward like a river made of thought Predictions, gain, and context mixing everything we've got The brain's not just receiving, it's predicting what will be Error signals climbing up the visual hierarchy Minimizing surprise through this computational spree That's how we see the world through feedback's mystery [Outro] Three hypotheses dancing in the neural night Attention, context, prediction making vision bright
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