The brain’s working memory system relies heavily on themesolimbic dopamine system and the delivery of reward sig-nals. The interaction between the prefrontal cortex (PFC) andthe basal ganglia are the main components simulated in work-ing memory models. The Working Memory Toolkit (WMtk) isa framework that allows the incorporation of working memoryinto robotic/artificial systems. The HWMtk is built on top ofWMtk by using holographic reduced representations for con-cept encoding. This allows end users to adopt the frameworkwithout the need to understand details of the algorithms in-volved. While the HWMtk captures human and animal per-formance on some cognitive tasks, tasks with multiple con-text layers are still problematic. We extended the HWMtkframework by adding a multilayer context reasoning work-ing memory system. We tested our system on the AX-CPTtask, 1-2-AX-CPT task and a 2-layer context task that is par-tially observable. Our results show that our model is capableof learning after a reasonable number of trials, thus making itamenable for comparison with human and animal performancedata.

BACKGROUND: As the overdose crisis continues in the U.S. and Canada, opioid use disorder (OUD) treatment outcomes for people with co-occurring psychiatric disorders are not well characterized. Our objective was to examine the influence of co-occurring psychiatric disorders on buprenorphine initiation and discontinuation. METHODS: This retrospective cohort study used multi-state administrative claims data in the U.S. to evaluate rates of buprenorphine initiation (relative to psychosocial treatment without medication) in a cohort of 236,198 people with OUD entering treatment, both with and without co-occurring psychiatric disorders, grouping by psychiatric disorder subtype (mood, psychotic, and anxiety-and-related disorders). Among people initiating buprenorphine, we assessed the influence of co-occurring psychiatric disorders on buprenorphine retention. We used multivariable Poisson regression to estimate buprenorphine initiation and Cox regression to estimate time to discontinuation, adjusting for all 3 classes of co-occurring disorders simultaneously and adjusting for baseline demographic and clinical characteristics. RESULTS: Buprenorphine initiation occurred in 29.3 % of those with co-occurring anxiety-and-related disorders, compared to 25.9 % and 17.5 % in people with mood and psychotic disorders. Mood (adjusted-risk-ratio[aRR] = 0.82[95 % CI = 0.82-0.83]) and psychotic disorders (aRR = 0.95[0.94-0.96]) were associated with decreased initiation (versus psychosocial treatment), in contrast to greater initiation in the anxiety disorders cohort (aRR = 1.06[1.05-1.06]). We observed an increase in buprenorphine discontinuation associated with mood (adjusted-hazard-ratio[aHR] = 1.20[1.17-1.24]) and anxiety disorders (aHR = 1.12[1.09-1.14]), in contrast to no association between psychotic disorders and buprenorphine discontinuation. CONCLUSIONS: We observed underutilization of buprenorphine among people with co-occurring mood and psychotic disorders, as well as high buprenorphine discontinuation across anxiety, mood, and psychotic disorders.