Effects of encoding and retrieval on the mechanism of item + context binding

Abstract

To investigate the neural mechanism of semantic representation and color context binding, we used electroencephalograph time frequency and coherence analyses to reveal local and long-range functional coupling in the encoding and retrieval phases of episodic memory. Fifteen undergraduates participated in the experiment and middle-frequency double-character Chinese words were used as stimuli in two types of study-test tasks (context recall and context recognition tests). Significant differences between item+context and item in the encoding phase were observed at the electrodes in the frontal region at 600-800 ms by time frequency analysis. Further differences were observed at 800 ms by independent component analysis: the frontal component and the coherent component of the triangle phase locking structure among the prefrontal, right parietal and left parietal-occipital regions. In the retrieval phase, differences between item+context and item were found on the electrodes at the central parietal and parietal-occipital regions at 400 ms by time frequency analysis, on the parietal-occipital component at 800 ms by independent component analysis and on the coherence component of the anterior right hemisphere and parietal-occipital regions at 1400 ms. In conclusion, the different effects of encoding and retrieval processing on 'binding' are reflected by the differing extents that brain regions engaged in cognitive operations. In the retrieval phase in particular, activities of the parietal-occipital region were specifically associated with 'binding', and coherence between frontal and temporal-parietal regions is a common brain activity in episodic memory.encoding, retrieval, binding, item, context, frontal and parietal-occipital coherence Citation: Xiao X, Ding J H, Guo C Y. Effects of encoding and retrieval on the mechanism of item+context binding.

Out and about: Subsequent memory effect captured in a natural outdoor environment with smartphone EEG

“…In fact, significant theta SMEs were only found for the first recall indoors, which refers to the indoor recall together with all possible outdoor recall outcomes (i.e., word hit‐location miss, word hit‐location hit not recalled as a pair [i.e., as originally encoded], word hit‐location hit recalled as a pair, word miss‐location hit, word miss‐location miss). Further, the effect was pronounced over right parietal and left parietotemporal, whereas theta activity related to item‐context binding has been reported bilaterally in frontal and temporal regions (Hasselmo & Stern, ; Summerfield & Mangels, ; Xiao, Ding, & Guo, ). High‐density EEG acquisition was not possible in the current study, which prevented us from undertaking a source analysis and exploring spatial patterns in more detail.…”