Posterior medial corticothalamic connectivity and consciousness.

In a foundational study published in this issue of Annals of Neurology, Fernández-Espejo et al1 report that diagnostic categories of disorders of consciousness can be stratified by diffusion tensor imaging (DTI) of connections among specific components of the defaultmode network (DMN).2 The DMN includes the corticocortical and thalamocortical connections of the medial prefrontal, posterior medial regions (including the posterior cingulate [PCC] and precuneus [PCu]) and the temporoparietal junction (TPJ), which are identified by functional neuroimaging techniques to demonstrate strong functional connectivity.2, 3 he DMN contains some of the most metabolically active regions of the human brain at rest4 and is proposed to play a key role in maintaining a state of readiness of internal representations accessed during self-monitoring or shaping of motivated actions.5 Prior studies have linked outcomes of vegetative state (VS) and minimally conscious state (MCS) after brain injuries to the strength of correlation of blood oxygen level-dependent signals across the DMN.6