Every few decades there’s a major new neuroscience discovery that changes everything. I’m not talking about your garden variety discovery. Those happen frequently (this is the golden age of neuroscience after all). But no, what I’m talking about are the holy-moly, scales-falling-from-your-eyes, time-to-rewrite-the-textbooks, game-changing discoveries. Well one was reported in this last month—simultaneously by two separate labs—and it redefines the primary organizational principle of the visual system in the cortex of the brain. This may sound technical, but it concerns how we see light and dark, and the perception of contrast. Since all sensation functions at the pleasure of contrast, these new discoveries impact neuroscience and psychology as a whole.
Hubel & Wiesel discovered that the cortex did a fundamentally different thing than the retina and the thalamus. The cortex interpreted the meaning of the information, as opposed to just continuing to pass the image along from level to level. It broke the image down into features that were critical to object recognition and survival. The first step in their amazing research journey was their discovery that neurons in the primary visual cortex were not only retinotopic, but also orientation-specific—they preferred specific edge-tilts in the visual scene. This showed that the cortex of the brain—the brain part most associated with higher mammals and especially with human intelligence—could analyze the visual scene and pull out specific features from the images transmitted by the eyes. This started a revolution in brain science—which lasted for decades and inspired thousands of young scientists like me—to search the other parts of cortex to determine how sensory and cognitive features were processed in the different regions. Lots of other things have happened since, but to my mind, nothing of equal impact has occurred to change the way we look at the principles of cortical organization. Until now.
Now, two separate labs, Jose-Manuel Alonso’s lab at State University of New York School of Optometry, and David Fitzpatrick’s lab at the Max Planck Florida Institute of Neuroscience, have made a discovery that I believe to be of equal importance as Hubel & Wiesel’s fundamental discovery. It’s all predicted by the way the retina eventually wires into cortex. Wow. Other sensory systems may be similarly wired so that the contrast features of sound, touch, taste and smell, are also organized by the antagonistic push-pull of their fundamental properties. Right? I don’t know: nobody does. But now we have a new conceptual hammer with which to find out. It’s an exciting time for brain mapping and you can bet that my peeps are lining up to start driving some nails.