Thalamo-cortical interactions and synchronous oscillations in MEG data

The thalamus has received a renewed interest in systems neuroscience because emerging evidence indicates that the thalamus may modulate cortical responses according to behavioral demands. Moreover, there is evidence to suggest that in addition to normal brain functioning, thalamic–cortical (TC) interactions are critically implicated in neuropsychiatric disorders, such as schizophrenia. In this chapter, we will discuss the possibility to examine TC interactions using magnetoencephalography (MEG), a technique that is commonly considered as too unreliable to monitor activity generated by thalamic sources. Here, we argue that if certain requirements are met, MEG can be employed to investigate TC interactions by combining advanced source reconstruction techniques and novel connectivity measures. Specifically, we summarize evidence from MEG experiments that examined alpha–gamma coupling in TC networks during resting-state recordings as well as data from a study that tested the effects of ketamine on neural oscillations in healthy volunteers. We will discuss the implication of these findings for the understanding of normal and abnormal brain functioning as well as further steps to validate and improve MEG as a noninvasive technique to probe interactions in TC circuits