eLife Assessment
The study provides valuable insights into the mechanisms underlying neurovascular coupling; the authors present solid evidence demonstrating that layer II/III pyramidal neurons can induce vasoconstriction under conditions of intense optogenetic stimulation. They identify three distinct signalling pathways responsible for this effect, involving direct action on smooth muscle cells, as well as indirect modulation via interneurons or astrocytes. This work will be of interest to the broader neuroscience community and has potential implications for understanding pathological microcirculation in the brain, particularly in conditions characterized by strong excitatory neuronal activation. There are however questions that should be clarified, especially the conflict between three identified parallel pathways and the observed complete inhibition of the constriction by blockage of the NPY Y1 receptors.