What resolves this contention: Whether PV-only optogenetic perturbations are su…

What resolves this contention: Whether PV-only optogenetic perturbations are sufficient probes of the ISN regime, or whether they can give misleading non-ISN signatures (and conversely whether they can give ISN-positive signatures in non-ISN networks). / Awake mouse auditory cortex (A1) operates as an ISN: optogenetic inactivation of PV interneurons produces paradoxical increases in IPSCs onto pyramidal cells. / Reliable detection of an ISN regime in realistic cortex requires perturbing a large fraction of inhibitory neurons; PV-only optogenetic perturbations are insufficient and earlier negative results were therefore inconclusive.