Discovery of Neurons Encoding Visual Illusions

In a new study published in the journal “Nature Neuroscience,” scientists at the University of California, Berkeley, in collaboration with teams at the Allen Institute, have discovered a special type of neuron known as “illusion-encoding cells,” which play a pivotal role in making the brain perceive shapes that do not actually exist. These cells receive instructions from higher brain regions and complete missing lines in the visual cortex, contributing to what we actually see.

Illusion-Encoding Cells: Function and Mechanism

Illusion-encoding cells are specialized cells in the primary visual cortex (V1) that respond to patterns of visual illusions, creating illusory contours through a process known as “repetitive pattern completion.” These cells receive signals from higher brain areas, where the initial representation of the visual illusion is formed, and then it is sent back to the primary visual cortex to be received by these specialized cells.

This process is similar to how a manager gives instructions to an employee to perform a task. In this case, instructions are sent to the brain to see or perceive something that is not actually present, like seeing a square even though the visual input consists of four incomplete circular shapes.

Neural Stimulation Experiments and Illusion Recreation

The researchers monitored the patterns of electrical brain activity in mice when presented with illusory images like the Kanizsa triangle. They then used a technique known as “two-photon imaging” to stimulate these illusion-encoding cells using light beams, even in the absence of an illusory image.

They observed that even without the illusion, these cells could produce the same patterns of brain activity that occur when an illusory image is present. This enhances our understanding of how the visual and perceptual systems in the brain work and how they are affected by disorders where these abnormal patterns occur.

Clinical Importance and Potential Applications

These discoveries are of great significance for understanding cognitive disorders like schizophrenia and other conditions that involve false perceptions. Understanding how these visual illusions are formed in the brain can help develop new therapeutic approaches for these conditions.

Researchers suggest that understanding the correct parts of the brain and the cells responsible for these activities can provide valuable information for treating diseases that affect perception.

Conclusion

This study reveals a significant shift in our understanding of the process of vision and perception, showing that it is no longer considered a passive process limited to receiving information from the external world, but an active process involving complex interpretations and brain computations that affect what we actually see. These findings open the door to a deeper understanding of how reality is formed in the brain and its impact on cognitive disorders.