Sumary of Behind the scenes, brain circuit ensures vision remains reliable:
- Ideally the same image would be reliably represented the same way each time, but instead different groups of cells in the visual cortex can become stimulated by the same scenes.
- A team of neuroscientists in The Picower Institute for Learning and Memory at MIT found out by watching the brains of mice while they watched movies.
- What the researchers discovered is that while groups of “excitatory” neurons respond when images appear, thereby representing them in the visual cortex, activity among two types of “inhibitory” neurons combines in a neatly arranged circuit behind the scenes to enforce the needed reliability.
- The researchers were not only able to see and analyze the patterns of these neurons working, but also once they learned how the circuit operated, they took control of the inhibitory cells to directly manipulate how consistently excitatory cells represented images.
- “The same neurons should be firing in the same way when I look at something, so that the next time and every time I look at it, it’s represented consistently.
- ” Research scientist Murat Yildirim and former graduate student Rajeev Rikhye led the study, which required a number of technical feats.
- To watch hundreds of excitatory neurons and two different inhibitory neurons at work, for instance, they needed to engineer them to flash in distinct colors under different colors of laser light in their two-photon microscope.
- Taking control of the cells using a technology called “optogenetics” required adding even more genetic manipulations and laser colors.