Professor of Cognitive Neuroscience
- Tutorial Fellow, Wadham College
Episodic Memory and Sleep
How do brief experiences turn into lasting memories? My work focuses on the neural mechanisms supporting episodic memory in humans. I am interested in how medial temporal lobe (MTL) regions and their oscillatory dynamics contribute to successful encoding, consolidation and recollection of experiences. The research in my group combines electrophysiological recordings (intracranial and scalp EEG, MEG), functional magnetic resonance imaging (fMRI @ 3T and 7T), behavioural testing and experimental brain stimulation.
Neurophysiology of sleep and memory consolidation
We use high-density scalp EEG, intracranial EEG in epilepsy patients and simultaneous EEG-fMRI to understand the mechanisms of systems consolidation. What are the exact roles of cortical slow oscillations (SOs), thalamocortical spindles and hippocampal ripples during non-REM sleep? What types of memories benefit the most from the precise interaction of these oscillations? How is offline reactivation and replay coordinated in the human brain? Can we bolster memory consolidation via experimental brain stimulation (transcranial electrical stimulation, targeted memory reactivation, closed loop stimulation)?
Functional neuroanatomy of episodic memory
We use standard (3T) and high-field (7T) functional magnetic resonance imaging (fMRI) as well as direct intracranial recordings from the human hippocampus to understand the division of labour within the MTL in service of episodic memory. What are the roles of the hippocampus and the entorhinal cortex (EC) beyond spatial navigation? Where does domain-specificity seen in MTL cortex turn to domain-generality seen in hippocampus? How does our memory system rapidly switch between encoding and retrieval states?
The hippocampus as the switchboard between perception and memory.
Treder MS. et al, (2021), Proc Natl Acad Sci U S A, 118
Theta rhythmicity governs human behavior and hippocampal signals during memory-dependent tasks
ter Wal M. et al, (2021), Nature Communications, 12
Disentangling neocortical alpha/beta and hippocampal theta/gamma oscillations in human episodic memory formation.
Griffiths BJ. et al, (2021), Neuroimage, 242
Sleep bolsters schematically incongruent memories
Ashton J. et al, (2021)
Alpha/beta power decreases during episodic memory formation predict the magnitude of alpha/beta power decreases during subsequent retrieval
Griffiths BJ. et al, (2021), NEUROPSYCHOLOGIA, 153