AsianScientist (Oct. 3, 2016) – A study in Nature Neuroscience has shown the first experimental evidence that a region of the mouse brain acts like a GPS navigator in the absence of a sound cue signaling the location of the reward.
Suppose you woke up in your bedroom with the lights off and wanted to get out. While heading toward the door with your arms out, you would predict the distance to the door based on your memory of your bedroom and the steps you have already made. If you touch a wall or furniture, you would refine the prediction. This is an example of how important it is to supplement limited sensory input with your own actions to grasp the situation. How the brain comprehends such a complex cognitive function is described by a theory called ‘dynamic Bayesian inference.’
Researchers Dr. Akihiro Funamizu, Professor Bernd Kuhn, and Professor Kenji Doya from the Okinawa Institute of Science and Technology Graduate University built a virtual reality system in which a mouse can be made to believe it was walking around freely, but in reality, it was fixed under a microscope.
They analyzed the brain activity of mice approaching a reward while experiencing interrupted sound inputs. As the mice approached a reward site, they exhibited increased anticipatory licking even when sound cues were intermittently presented. Interestingly, when the researchers injected a drug that suppresses neural activities in a region of the brain called the parietal cortex, the mice did not display anticipatory licking, suggesting that the parietal cortex plays a role in predicting the goal position.
In another study, Doya’s team also showed that a neural circuit including the parietal cortex was activated when human subjects performed mental simulation in a functional MRI scanner. The research team aims to further analyze the data to better understand the mechanisms underlying mental simulation.
The article can be found at: Funamizu et al. (2016) Neural Substrate of Dynamic Bayesian Inference in the Cerebral Cortex.
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Source: Okinawa Institute of Science and Technology Graduate University.
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