Alcohol drinking is associated with greater calcium activity in mouse central amygdala dynorphin-expressing neurons

Alcohol use disorder (AUD) is a chronic disease that poses significant economic burden and health risks. It is pivotal to better understand brain mechanisms engaged by alcohol that promote misuse. The central amygdala (CeA) has emerged as a key mediator of excessive alcohol consumption in preclinical models. A dynorphin-expressing subpopulation within the CeA (CeA^Dyn) has been implicated in excessive alcohol drinking, yet how cellular activity of CeA^Dyn neurons relates to ongoing alcohol drinking is not well-understood. The current study interrogated the engagement of CeA^Dyn neurons in male and female mice during voluntary alcohol consumption using fiber photometry and compared this cellular response with that of other solutions having similar motivational and/or taste characteristics. Activity of a calcium sensor, GCaMP7f, expressed in mouse CeA^Dyn neurons was recorded and time-locked to drinking bouts. Advanced fiber photometry normalization and mixed modeling methods were developed to better resolve effects, revealing relatively large increases in CeA^Dyn neuron calcium transients after bouts of alcohol drinking compared to water or sucrose drinking. This indicates that these neurons are uniquely engaged during alcohol consumption. Alcohol-specific drinking behavior (i.e., longer bout durations) did not fully explain signal differences between alcohol and other solutions nor did the relatively increased alcohol response diminish over time. No other conditions or solutions tested reproduced the pronounced change in CeA^Dyn activity associated with alcohol drinking. These findings support the presence of a unique functional signature for alcohol in a cell population known to control excessive alcohol drinking and further advance fiber photometric normalization and analytical methods.