Parvalbumin interneurons contribute to spontaneous hemodynamic fluctuations

Resting-state hemodynamic fluctuations take place over broad temporal scales and are reported to be closely linked to gamma-band neural activity, yet whether specific cell types drive these fluctuations remains unclear. Given the established contribution of parvalbumin (PV) neurons in generating gamma oscillations, they are prime candidates. Using chemogenetic tools in awake PV-Cre mice, we modulated PV interneuron activity and measured effects on neural network activity, EEG, and hemodynamics. Two-photon calcium imaging confirmed their modulation of excitatory neurons as well as local vascular changes. PV chemogenetic suppression reduced EEG gamma power, increased low-frequency EEG activity, and elevated basal CBF. Two-photon imaging under control conditions showed increased basal arterial diameter and significantly greater vascular fluctuation in deeper cortical layers enriched with PV cells, but not in superficial layers. Importantly, PV suppression significantly weakened the correlation between the EEG gamma power and CBF. These findings provide evidence that PV interneuron contribute to spontaneous neurovascular dynamics and to the link between gamma oscillations and resting-state hemodynamic signals, pointing to a significant role in neurovascular changes during non-task-engaged brain states.