Noninvasively Decoding the Contents of Visual Working Memory in the Human Prefrontal Cortex within High-gamma Oscillatory Patterns

摘要

The temporal maintenance and subsequent retrieval of informationnthat no longer exists in the environment is called workingnmemory. It is believed that this type of memory is controlled bynthe persistent activity of neuronal populations, including the prefrontal,ntemporal, and parietal cortex. For a long time, it has beenncontroversially discussed whether, in working memory, the PFCnstores past sensory events or, instead, its activation is an extramnemonicnsource of top–down control over posterior regions.nRecent animal studies suggest that specific information aboutnthe contents of working memory can be decoded from populationnactivity in prefrontal areas. However, it has not been shownnwhether the contents of workingmemory during the delay periodsncan be decoded from EEG recordings in the human brain. Wenshow that by analyzing the nonlinear dynamics of EEG oscillatorynpatterns it is possible to noninvasively decode with high accuracy,nduring encoding and maintenance periods, the contents of visualnworking memory information within high-gamma oscillations innthe human PFC. These results are thus in favor of an active storagenfunction of the human PFC in working memory; this, withoutnruling out the role of PFC in top–down processes. The abilitynto noninvasively decode the contents of workingmemory is promisingnin applications such as brain computer interfaces, togethernwith computation of value function during planning and decisionnmaking processes.