Medial prefrontal theta phase coupling during spatial memory retrieval.
Memory retrieval is believed to involve a disparate network of areas, including medial prefrontal and medial temporal cortices, but the mechanisms underlying their coordination remain elusive. One suggestion is that oscillatory coherence mediates inter-regional communication, implicating theta phase and theta-gamma phase-amplitude coupling in mnemonic function across species. To examine this hypothesis, we used non-invasive whole-head magnetoencephalography (MEG) as participants retrieved the location of objects encountered within a virtual environment. We demonstrate that, when participants are cued with the image of an object whose location they must subsequently navigate to, there is a significant increase in 4-8 Hz theta power in medial prefrontal cortex (mPFC), and the phase of this oscillation is coupled both with ongoing theta phase in the medial temporal lobe (MTL) and perceptually induced 65-85 Hz gamma amplitude in medial parietal cortex. These results suggest that theta phase coupling between mPFC and MTL and theta-gamma phase-amplitude coupling between mPFC and neocortical regions may play a role in human spatial memory retrieval.
NIMH-UCL Joint Neuroscience Graduate Partnership Program, National Institute of Mental Health, Bethesda, Maryland; Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, Maryland; University College London, Institute of Cognitive Neuroscience, Alexandra House, London, WC1N 3AR, United Kingdom; University College London, Institute of Neurology, London, WC1N 1PJ, United Kingdom.
Raphael
R
Kaplan
Daniel
D
Bush
Mathilde
M
Bonnefond
Peter A
PA
Bandettini
Gareth R
GR
Barnes
Christian F
CF
Doeller
Neil
N
Burgess
D003463:Cues; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D065852:Spatial Memory / Q000502:physiology*; D013826:Theta Rhythm; D014584:User-Computer Interface
MEG; MTL; hippocampus; mPFC; oscillations