![]() ![]() Calcium signal imaging following ischemic stroke found that the magnitude of spreading depolarizations were significantly smaller in awake mice (Balbi et al., 2017) while laser speckle contrast imaging (LSCI) of photothrombotic stroke observed larger infarct sizes in awake rats compared to their isoflurane-anesthetized counterparts (Lu et al., 2017). ![]() Two-photon phosphorescence lifetime microscopy showed that tissue oxygenation is twice as high under isoflurane anesthesia compared to the awake state and exhibited large layer-specific differences within the cortical vasculature (Lyons et al., 2016). Functional magnetic resonance imaging (fMRI), laser Doppler flowmetry, and intrinsic signal optical imaging have all established that isoflurane increases basal cerebral blood flow (CBF) while attenuating and delaying the hemodynamic response to local neural activity via neurovascular coupling (Desai et al., 2011 Aksenov et al., 2015 Takuwa et al., 2012 Pisauro et al., 2013). There have been numerous imaging modalities used to examine the effects of isoflurane on cerebral hemodynamics. For these reasons and more (Gao et al., 2017), there is a growing effort within the neuroscience community to transition to un-anesthetized awake animal models in order to more accurately interpret neurophysiological and behavioral experiments and more readily translate findings to awake human physiology. These effects can mask the benefits of prospective neuroprotective therapeutics or interventions and confound the outcomes of long-term studies (Kapinya et al., 2002 Seto et al., 2014). Isoflurane also conveys potential neuroprotective effects that reduce and delay the severity of cerebral ischemia (Kitano et al., 2006 Kawaguchi et al., 2000 Sakai et al., 2007 Li et al., 2013 Lu et al., 2017). However, isoflurane has been shown to reduce neuronal activity (Aksenov et al., 2015), interfere with functional connectivity at higher doses (Xie et al., 2019), and suppress the magnitude and speed of neurovascular coupling (Masamoto and Kanno, 2012 Takuwa et al., 2012 Pisauro et al., 2013). Volatile inhalation anesthetics, such as the halogenated ether isoflurane (Eger, 1981), are commonly utilized to immobilize animals during imaging while allowing for fine control over the depth of anesthesia and consciousness. The use of general anesthesia during neuroimaging is ubiquitous across many animal models despite systemic effects on neurophysiological state and cardiovascular function (Slupe and Kirsch, 2018).
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