A paradigm for ethanol consumption in head-fixed mice during prefrontal cortical two-photon calcium imaging

Abstract

AbstractThe prefrontal cortex (PFC) is a hub for higher-level cognitive behaviors and is a key target for neuroadaptations in alcohol use disorders. Preclinical models of ethanol consumption are instrumental for understanding how acute and repeated drinking affects PFC structure and function. Recent advances in genetically encoded sensors of neuronal activity and neuromodulator release combined with functional microscopy (multiphoton and one-photon widefield imaging) allow multimodalin-vivoPFC recordings at subcellular and cellular scales. While these methods could enable a deeper understanding of the relationship between alcohol and PFC function/dysfunction, they require animals to be head-fixed. Here, we present a method in mice for binge-like ethanol consumption during head-fixation. Male and female mice were first acclimated to ethanol by providing home cage access to 20% ethanol (v/v) for 4 or 8 days. After home cage drinking, mice consumed ethanol from a lick spout during head-fixation. We used two-photon calcium imaging during the head-fixed drinking paradigm to record from a large population of PFC neurons (>1000) to explore how acute ethanol affects their activity. Drinking modulated activity rates in a subset of neurons on slow (minutes) and fast (seconds) time scales but the majority of neurons were unaffected. Moreover, ethanol intake did not significantly affect network level interactions in the PFC as assessed through inter-neuronal pairwise correlations. By establishing a method for binge-like drinking in head-fixed mice, we lay the groundwork for leveraging advanced microscopy technologies to study alcohol-induced neuroadaptations in PFC and other brain circuits.HighlightsC57BL/6J mice voluntarily consume ethanol to binge-like levels during head-fixation, with females consuming more ethanol than males.Mice show differences in frontloading and licking behavior for head-fixed ethanol and sucrose consumption.Head-fixed paradigm enables two-photon calcium imaging in the anterior cingulate cortex subdivision of the prefrontal cortex.Acute ethanol increases and decreases single neuron activity at fast (seconds) and slow (minutes) time scales but does not alter pairwise correlations between neurons.