In the context of brain hemodynamics regulation, a small group of neuronal subtypes play an outsized role, therefore, it is critical to investigate neurovascular coupling for these cell-type specific neurons. Among these, somatostatin-expressing (SST) interneurons represent a heterogeneous class of GABAergic cells implicated in sensory-evoked circuit dynamics, yet how their activity varies across behavioral states and brain regions remains incompletely understood. Here, we combined in vivo calcium imaging with cell type specific optogenetic stimulation to examine how SST interneuron activity influences brain hemodynamics in awake, head-fixed mice. Widefield fluorescence imaging through a polished thin-skull cranial window allowed simultaneous measurement of cortical blood volume, tissue oxygenation, and SST calcium signals in somatosensory cortex. During voluntary locomotion and whisker stimulation, both blood volume and tissue oxygenation increased, paralleled by robust increases in SST calcium activity. Optogenetic activation of SST interneurons produced a delayed but pronounced hemodynamic response, consisting of a significant rise in blood volume and oxygenation followed by a characteristic undershoot. Notably, SST activation was sufficient to evoke vascular responses comparable to, or even larger than, those generated by sensory stimulation. Ongoing work will further delineate how SST-driven vascular modulation varies across behavioral states and cortical areas. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Morris et al. (Fri,) studied this question.