Thalamic pathways underlying prefrontal cortex–medial temporal lobe oscillatory interactions

• Three thalamo–cortical circuits link declarative memory systems and neural oscillations.
• The anterior thalamus connects the hippocampus with the prefrontal cortex (PFC) in theta synchrony for recollection.
• The medial dorsal thalamus (MTL) connects the MTL cortex with the PFC in beta synchrony for familiarity.
• The pulvinar connects the visual/parietal cortex with the PFC in alpha synchrony for gating.

As focus shifts to large-scale network interactions involved in memory, it is becoming increasingly clear that oscillatory dynamics are critically involved. A number of studies have shown a negative correlation between memory retrieval in alpha and beta power, and a positive correlation between retrieval and theta power. In this opinion article, we suggest three thalamic sub-regions responsible for the coordination of oscillatory activity and the facilitation of memory processes. Specifically, the medial dorsal nucleus is related to changes in beta synchrony, the pulvinar is responsible for alpha synchrony, and the anterior thalamus is related to theta synchrony. These pathways may be modulated via frontal control, and changes in oscillations could be used to track the engagement of underlying memory systems.