Slow-theta power decreases during item-place encoding predict spatial accuracy of subsequent context recall.
Human hippocampal theta oscillations play a key role in accurate spatial coding. Associative encoding involves similar hippocampal networks but, paradoxically, is also characterized by theta power decreases. Here, we investigated how theta activity relates to associative encoding of place contexts resulting in accurate navigation. Using MEG, we found that slow-theta (2-5Hz) power negatively correlated with subsequent spatial accuracy for virtual contextual locations in posterior hippocampus and other cortical structures involved in spatial cognition. A rare opportunity to simultaneously record MEG and intracranial EEG in an epilepsy patient provided crucial insights: during power decreases, slow-theta in right anterior hippocampus and left inferior frontal gyrus phase-led the left temporal cortex and predicted spatial accuracy. Our findings indicate that decreased slow-theta activity reflects local and long-range neural mechanisms that encode accurate spatial contexts, and strengthens the view that local suppression of low-frequency activity is essential for more efficient processing of detailed information.
['Crespo-García|Maité|M|', 'Zeiller|Monika|M|', 'Leupold|Claudia|C|', 'Kreiselmeyer|Gernot|G|', 'Rampp|Stefan|S|', 'Hamer|Hajo M|HM|', 'Dalal|Sarang S|SS|']
D000328:Adult D000069280:Electrocorticography D004827:Epilepsy D005260:Female D006624:Hippocampus D006801:Humans D015225:Magnetoencephalography D008297:Male D011939:Mental Recall D017397:Prefrontal Cortex D065854:Spatial Navigation D013702:Temporal Lobe D013826:Theta Rhythm D055815:Young Adult
MEG Hippocampus Intracranial EEG Source localization Spatial navigation