Theta Signal Transfer from Parietal to Prefrontal Cortex Ignites Conscious Awareness of Implicit Knowledge during Sequence Learning

• DOI: 10.1523/jneurosci.2172-22.2023
• Publication Date: 2023-08-22T17:50:26Z
• Authors: Yang Lu; Xiuyan Guo; Xue Weng; Haoran Jiang; Huidan Yan; Xianting Shen; Zhengning Feng; Xinyue Zhao; Lin Li; Li Zheng; Zhiyuan Liu; Weiwei Men; Jia-Hong Gao
• Keywords: Implicit Learning

Unconscious acquisition of sequence structure from experienced events can lead to explicit awareness the pattern through extended practice. Although implicit-to-explicit transition has been extensively studied in humans using serial reaction time (SRT) task, subtle neural activity supporting this remains unclear. Here, we investigated whether frequency-specific signal transfer contributes transition. A total 208 participants (107 females) learned a multisession SRT allowing us observe transitions. Session-by-session measures participants’ for knowledge were conducted during task identify session when occurred. By analyzing course RT data switchpoint modeling, identified an increase learning benefit specifically at session. Electroencephalogram (EEG)/magnetoencephalogram (MEG) recordings revealed increased theta power parietal (precuneus) regions one before (pretransition) and prefrontal (superior frontal gyrus; SFG) Phase entropy (PTE) analysis confirmed that directional precuneus → SFG occurred pretransition its strength positively predicted improvement subsequent Furthermore, repetitive transcranial magnetic stimulation (TMS) modulated altered SFG, resulting changes both rate specific point Our brain-stimulation evidence supports role igniting conscious implicitly acquired knowledge. SIGNIFICANCE STATEMENT There exists pervasive phenomenon wherein individuals unconsciously acquire patterns their environment, gradually becoming aware underlying regularities repeated While previous studies have established robustness humans, refined mechanisms facilitating access implicit remain poorly understood. demonstrate activity, known be crucial awareness, is triggered by originating posterior brain region, precuneus. employing techniques, establish causal link between occurrence awareness. findings unveil mechanism which becomes consciously accessible human cognition.