Neural mechanisms based on predictive coding in frontal cortex during cognitive tasks

2018 Fiscal Year Final Research Report

• Project/Area Number: 26290001
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology / General neuroscience
• Research Institution: Tohoku University
• Principal Investigator: Mushiake Hajime 東北大学, 医学系研究科, 教授 (80219849)
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: 前頭葉

Outline of Final Research Achievements

According to predictive coding, the brain is constantly generating and updating a working model. In each region, the predicting model is compared to the sensory input or feedback signals. If they match, the model is maintained, but if they do not match, a Prediction Error is sent back up the network and the model is updated. Our hypothesis is beta and gamma rhythms reflect these processes.
In the present study, beta and high-gamma activities in frontal areas of monkeys were analyzed during performance of a bimanual task that required updating and maintenance of the memory of action sequences. Beta power was attenuated during early delay periods of updating trials but was increased during maintenance trials, while there was a reciprocal increase in high-gamma power during updating trials. In conclusion, beta rhythm is related to top-down signals and contribute to maintain the current model. In contrast, gamma rhythm is related to bottom-up signals to update current models.

Free Research Field

神経生理学

Academic Significance and Societal Importance of the Research Achievements

ベータ波は　パーキンソン病などの脳疾患で更新しており、前頭葉と基底核でベータ波の同期が認められる事が知られている。このベータ波の意義は、我々の今回の結果に従えば予測符号化の、維持機構が強まり、逆に予測誤差で更新する機構が障害された状態と解釈できる。すなわち健常者での神経機構とパーキンソン病の神経系機構には、共通の神経基盤があり、そのバランスが崩れた状態と考えられる。このような予測符号化の神経機構の理解が、病態の新たな理解や治療方法の提案に貢献できると考えられる。