Neurovascular coupling dysfunction of the frontal‒thalamic circuit in postconcussion syndrome.

Postconcussion syndrome (PCS) is characterized by alterations in perfusion and neural activity within specific regions, such as the frontal‒thalamic circuit. Despite extensive research on the neurovascular coupling (NVC) function of the PCS, how the involved brain regions interact as a dynamic network in the processing of cognitive and behavioral functions is still elusive. We recruited 38 participant with PCS and 38 healthy controls for magnetic resonance imaging examinations. We subsequently investigated four types of NVC, namely, amplitude of low-frequency fluctuation (ALFF), fractional ALFF, regional homogeneity, degree centrality, cerebral blood perfusion, and associated functional networks, on the basis of dynamic causal modeling (DCM). NVC and spectral DCM analyses revealed a significant reduction in excitatory cortical connectivity from the left thalamus to the left middle frontal gyrus and from the right thalamus to the right middle frontal gyrus, whereas inhibitory cortical connectivity from the right middle frontal gyrus to the right thalamus also decreased. Notably, an increase in excitatory cortical connectivity from the left putamen to the left middle frontal gyrus was observed, which may represent a compensatory mechanism. The distinctive pattern of altered neurovascular coupling in the frontal‒thalamic circuit of PCS participant may underlie the observed executive and cognitive dysfunctions.