Human memory strength is predicted by theta-frequency phase-locking of single neurons by Rutishauser et al
Abstract: Learning from novel experiences is a major task of the central nervous system. In mammals, the medial temporal lobe is crucial for this rapid form of learning1. The modification of synapses and neuronal circuits through plasticity is thought to underlie memory formation2. The induction of synaptic plasticity is favoured by coordinated action-potential timing across populations of neurons3. Such coordinated activity of neural populations can give rise to oscillations of different frequencies, recorded in local field potentials. Brain oscillations in the theta frequency range (3–8 Hz) are often associated with the favourable induction of synaptic plasticity as well as behavioural memory4. Here we report the activity of single neurons recorded together with the local field potential in humans engaged in a learning task. We show that successful memory formation in humans is predicted by a tight coordination of spike timing with the local theta oscillation. More stereotyped spiking predicts better memory, as indicated by higher retrieval confidence reported by subjects. These findings provide a link between the known modulation of theta oscillations by many memory-modulating behaviours and circuit mechanisms of plasticity.