Determining the acute pharmacological effects of alcohol in rodent medial prefrontal cortex

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Project Summary: A wealth of data exists describing how alcohol influences neuronal function in brain regions necessary for complex cognitive functions such prefrontal cortex (PFC). These data have proven critical to form hypotheses regarding how alcohol consumption might lead to altered behavioral states (e.g. intoxication) and the associated negative outcomes (e.g. risky behavior, violence). However, these data have been exclusively collected in reduced preparations, such as anesthetized animals or ex vivo slice preparations, and therefore may not adequately model how neural function is impaired by alcohol consumption in behaving subjects. Published and preliminary data from our group indicate that the broad reductions in neural firing previously observed in reduced preparations are not observed in awake behaving animals. This calls into question current explanations of how alcohol affects neural function, indicating that there is a critical need for additional experiments that demonstrate specifically how alcohol consumption affects neural function in the PFC of awake behaving animals. The long-term goal of this work is to create a unified model of how alcohol consumption alters the computational properties of PFC and leads to impaired behavioral control. Towards this goal, a series of experiments are proposed in rat models to test the overarching hypothesis that alcohol consumption leads to reductions in functional connectivity in PFC networks. In Specific Aim 1, a series of in vivo approaches will determine how oral consumption of alcohol influences neural activity in medial PFC (mPFC) networks. A combination of microdialysis, large-scale neural recordings, and optogenetics will be performed to determine the cell type- and layer-specific effects of alcohol consumption on neural activity. Experiments will be performed to determine which changes in neural activity evoked by oral consumption are conserved following local application of physiologically-relevant concentrations of alcohol within mPFC. Specific Aim 2 will determine which changes in neural activity observed in vivo are conserved ex vivo. In this Aim we will trace the local effects of alcohol on mPFC from the single cell to the microcircuit level. Glutamate uncaging will be combined with patch-clamp electrophysiology to assess network function and single cell function. These approaches will synergize with those in Specific Aim 1 to determine which changes in neural activity following alcohol consumption are conserved across levels of neural function and in each preparation. Collectively, these data will facilitate future studies that will integrate how the influence of consumed alcohol on cellular function translates into altered network properties and, ultimately, impaired behavioral states. Future studies will also assess changes in neural function in brain-wide networks and if/how the observations herein are altered following extended alcohol use. In sum, this proposal seeks to clarify a long held misconception in the alcohol field and answer a fundamental question on how alcohol effects neural activity.