In a recent study highlighted by Ars Technica, neuroscientists have uncovered new insights into how the brain constructs visual illusions—experiences where we perceive things that aren’t physically present. This research focuses on the neural mechanisms that allow us to “see” edges, shapes, or motion that don’t exist in the external world but are vividly experienced in our minds.
The study centers on a phenomenon known as illusory contours, where the brain fills in missing visual information to create a coherent image. A classic example is the Kanizsa triangle, where three Pac-Man-like shapes arranged in a certain way cause the brain to perceive a triangle that isn’t actually drawn. The researchers used advanced imaging techniques to observe how specific neurons in the visual cortex respond to these illusions.
What they found is that certain neurons in the primary visual cortex (V1) and secondary visual areas (V2) become active even when the visual stimulus is incomplete. These neurons are not just reacting to light hitting the retina—they are participating in a predictive process, constructing a version of reality based on context and prior experience.
This discovery supports the theory that perception is not purely passive but involves active inference. The brain constantly predicts what it expects to see and fills in gaps when information is missing. This predictive coding model helps explain not only visual illusions but also broader cognitive phenomena, such as hallucinations or the way we interpret ambiguous sensory input.
Understanding these mechanisms has implications beyond neuroscience. It could inform the development of artificial vision systems, improve treatments for perceptual disorders, and deepen our grasp of how consciousness arises from neural activity.
In essence, the study reveals that seeing is not just believing—it’s also imagining. The brain’s ability to create coherent visual experiences from incomplete data is a testament to its complexity and adaptability.
Read More: The neurons that let us see what isn’t there – Ars Technica
