527. DYNAMIC REWIRING OF NEURAL CIRCUITS IN THE PRELIMBIC CORTEX IN METH ABSTINENCE

Abstract Background Methamphetamine (Meth) addiction presents a significant public health issue, leading to a rise in overdose cases and high rates of addiction. The intense internal psychological craving for meth drives individuals to engage in drug-seeking behavior, increasing the likelihood of relapse during periods of abstinence. Aims & Objectives Research has shown that the prelimbic cortex (PL) plays a vital role in various stages of meth abstinence, yet the specific circuit mechanisms through which the PL contributes to meth abstinence and the regulation of craving and relapse remain poorly understood. Method A self-administration male mice model was developed through exposure to meth, with withdrawal tests employed to evaluate drug-seeking behaviors during the abstinence period. Utilizing a variety of multidisciplinary techniques such as in vivo Ca2+ imaging, genetic mouse lines, activity-dependent cell labeling, viral-mediated chemo-genetic manipulation procedures, we investigated the response of PL neurons to meth abstinence and explored the involvement of distinct neuronal ensembles at various time points, as well as the behavioral consequences of manipulating different neuronal subtypes, including pyramidal neurons and interneurons. Results Meth abstinence induced heterogeneous neuronal activation within the PL, involving diverse subtypes of neurons, particularly emphasizing interneurons (INs). The initial phase of withdrawal (withdrawal day 1, WD1) primarily elicited neuronal activation in layers 2/3 of the PL, whereas by withdrawal day 15 (WD15), activation had shifted to layers 5/6. This layer-specific activation suggests a dynamic restructuring of neural circuits in response to varying stages of meth withdrawal. In vivo Ca2+ recording additionally identified unique activity patterns among different subsets of neurons. Significantly, somatostatin (SST) INs exhibited inhibition during the initial abstinence period (WD1), indicating a potential role in the onset of withdrawal. Conversely, parvalbumin (PV) INs displayed activation during the later abstinence period (WD15), suggesting their contribution to the later stages of withdrawal and potentially to the sustenance of abstinence. Additionally, the pharmacological suppression of SST INs during WD1 notably enhanced cue-induced meth-seeking behaviors, underscoring their significance in mitigating relapse during the early abstinence phase. On the contrary, the suppression of PV INs during WD15 resulted in the disruption of cue-induced meth-seeking behaviors, indicating a crucial role of PV INs in preventing relapse during the late stages of abstinence. Furthermore, distinct downstream circuit properties were observed in neurons activated at various points of withdrawal, suggesting that neuronal ensembles implicated in early and late abstinence stages utilize different neural pathways and mechanisms. These results highlight the intricate nature of the neural circuits in the PL implicated in meth addiction and withdrawal. Discussion & Conclusions Collectively, these results elucidate a crucial and evolving function for distinct subsets of interneurons in the PL during the period of meth abstinence. They underscore the active participation of specific neural circuits within the PL in the mechanisms underlying meth abstinence, and suggest the possibility of developing precise interventions that target particular neuronal subpopulations to reduce relapse and promote sustained recovery.