Recent research led by Shin and colleagues has provided compelling evidence that a specific type of neuron, previously suggested by earlier studies, constitutes a critical and well-defined subpopulation within the brain. These neurons are implicated in the process of local pattern completion in the primary visual cortex. “What we didn’t know is that these neurons drive local pattern completion within primary visual cortex,” remarked Shin. Adesnik added, “We showed that those cells are causally involved in this pattern completion process that we speculate is likely involved in the perceptual process of illusory contours.”
Future Behavioral Experiments Planned
However, the findings do not confirm that the mice were able to “see” illusory contours when these neurons were activated artificially. “We didn’t actually measure behavior in this study,” Adesnik clarified. “It was about the neural representation.” Currently, it can only be asserted that the IC-encoders could generate neural activity patterns similar to those seen during normal perception of illusory contours through imaging.
Shin acknowledged the limitations of their technical approach, stating, “It’s possible that the mice weren’t seeing them,” due to the relatively small number of neurons involved in the study. Future research may focus on expanding the number of neurons studied and introducing behavioral evaluations.
Adesnik outlined the next steps: “What we would do is photo-stimulate these neurons and see if we can generate an animal’s behavioral response even without any stimulus on the screen.” Currently, the method of optogenetics allows for stimulation of only a limited number of neurons, and IC-encoders are thought to be a sparse and dispersed population within the visual system. “For now, we have only stimulated a small number of these detectors, mainly because of technical limitations. IC-encoders are a rare population, probably distributed through the layers [of the visual system], but we could imagine an experiment where we recruit three, four, five, maybe even 10 times as many neurons,” he explained. “In this case, I think we might be able to start getting behavioral responses. We’d definitely very much like to do this test.”
Nature Neuroscience, 2025. DOI: 10.1038/s41593-025-02055-5
Federica Sgorbissa is a science journalist; she writes about neuroscience and cognitive science for Italian and international outlets.
