In line with this prediction, many studies in scalp EEG and MEG have demonstrated positive theta effects during memory tasks. Two studies that inaugurated this line of work in the mid-1990s used scalp EEG to show that theta power during the encoding of word items was correlated with subsequent successful recall or recognition of those items, compared to forgotten items (i.e. an SME) [15,16]. Several later studies replicated this result, again showing higher theta power during [17–20] or prior to [21,22] encoding of subsequently recognized or recalled items, higher theta-power during successful item-in-context encoding [23], higher theta power for hits compared to correct rejections [24,25] and higher theta power during recollection or correct source memory retrieval [26–30].
