13 research outputs found

    Frontal midline theta and N200 amplitude reflect complementary information about expectancy and outcome evaluation

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    Feedback ERN (fERN) and frontal midline theta have both been proposed to index a dopamine-like reinforcement learning signal in anterior cingulate cortex (ACC). We investigated these proposals by comparing fERN amplitude and theta power with respect to their sensitivities to outcome valence and probability in a previously collected EEG dataset. Bayesian model comparison revealed a dissociation between the two measures, with fERN amplitude mainly sensitive to valence and theta power mainly sensitive to probability. Further, fERN amplitude was highly correlated with the portion of theta power that is consistent in phase across trials (i.e., evoked theta power). These results suggest that although both measures provide valuable information about cognitive function of frontal midline cortex, fERN amplitude is specifically sensitive to dopamine reinforcement learning signals whereas theta power reflects the ACC response to unexpected events

    Reward feedback stimuli elicit high-beta EEG oscillations in human dorsolateral prefrontal cortex

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    Reward-related feedback stimuli have been observed to elicit a burst of power in the beta frequency range over frontal areas of the human scalp. Recent discussions have suggested possible neural sources for this activity but there is a paucity of empirical evidence on the question. Here we recorded EEG from participants while they navigated a virtual T-maze to find monetary rewards. Consistent with previous studies, we found that the reward feedback stimuli elicited an increase in beta power (20-30 Hz) over a right-frontal area of the scalp. Source analysis indicated that this signal was produced in the right dorsolateral prefrontal cortex (DLPFC). These findings align with previous observations of reward-related beta oscillations in the DLPFC in non-human primates. We speculate that increased power in the beta frequency range following reward receipt reflects the activation of task-related neural assemblies that encode the stimulus-response mapping in working memory

    Reward-based contextual learning supported by anterior cingulate cortex

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    The anterior cingulate cortex (ACC) is commonly associated with cognitive control and decision making, but its specific function is highly debated. To explore a recent theory that the ACC learns the reward values of task contexts (Holroyd & McClure in Psychological Review, 122, 54-83, 2015; Holroyd & Yeung in Trends in Cognitive Sciences, 16, 122-128, 2012), we recorded the event-related brain potentials (ERPs) from participants as they played a novel gambling task. The participants were first required to select from among three games in one "virtual casino," and subsequently they were required to select from among three different games in a different virtual casino; unbeknownst to them, the payoffs for the games were higher in one casino than in the other. Analysis of the reward positivity, an ERP component believed to reflect reward-related signals carried to the ACC by the midbrain dopamine system, revealed that the ACC is sensitive to differences in the reward values associated with both the casinos and the games inside the casinos, indicating that participants learned the values of the contexts in which rewards were delivered. These results highlight the importance of the ACC in learning the reward values of task contexts in order to guide action selection

    Beta oscillations following performance feedback predict subsequent recall of task-relevant information

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    Reward delivery in reinforcement learning tasks elicits increased beta power in the human EEG over frontal areas of the scalp but it is unclear whether these 20-30 Hz oscillations directly facilitate reward learning. We previously proposed that frontal beta is not specific to reward processing but rather reflects the role of prefrontal cortex in maintaining and transferring task-related information to other brain areas. To test this proposal, we had subjects perform a reinforcement learning task followed by a memory recall task in which subjects were asked to recall stimuli associated either with reward feedback (Reward Recall condition) or error feedback (Error Recall condition). We trained a classifier on post-feedback beta power in the Reward Recall condition to discriminate trials associated with reward feedback from those associated with error feedback and then tested the classifier on post-feedback beta power in the Error Recall condition. Crucially, the model classified error-related beta in the Error Recall condition as reward-related. The model also predicted stimulus recall from post-feedback beta power irrespective of feedback valence and task condition. These results indicate that post-feedback beta power is not specific to reward processing but rather reflects a more general task-related process

    BLOOM: A 176B-Parameter Open-Access Multilingual Language Model

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    Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License

    Preventive Effects of NSAIDs on Lung Tissue Oxidative Damage in an Animal Sepsis Model

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    Background/aim: Sepsis is a very heterogeneous syndrome that is caused by a dysregulated host response to infection. Inflammatory cascades have an important role in sepsis and can potentially be suppressed by anti-inflammatory compounds. So, this study was focused on the antiseptic effects of non-steroidal anti-inflammatory drugs (NSAIDs) on lung injuries based on cecal ligation and puncture (CLP) surgery. Materials and methods: Male wistar rats divided into 6 groups (n=50) as follows: Control, Laparotomy (LAP), CLP and three treatment groups. The rats were killed after 48 h and the lung tissue was subjected to antioxidant enzymes (LP (lipid peroxidation), MPO (myeloperoxidase), and GSH (Glutathione)) and inflammatory genes expression (cyclooxygenase-2 (COX-2), CD177 and MPO). Results: The results indicated that CLP caused lung injury by changes in antioxidant enzymes and genes expression (P<0.05). Treatments with indomethacin, celecoxib and aspirin as anti-inflammatory compounds significantly improved antioxidant enzymes by reducing LP and MPO level as well as genes expression and increasing level of GSH (P<0.05). Conclusion: Our results indicated that sepsis caused oxidative damage in the lung tissue, and the uses of NSAIDs were effective in preventing and improving these injuries

    Synergistic effects of deuterium depleted water and Mentha longifolia L. essential oils on sepsis-induced liver injuries through regulation of cyclooxygenase-2

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    Context: Mentha longifolia L. (Lamiaceae), a traditional medicinal herb, has been highly valued for exhibiting antimicrobial, antioxidant and antispasmodic properties. Objective: For the first time, the synergetic anti-inflammatory effects of deuterium depleted water (DDW) and M. longifolia essential oils (ML) were investigated in experimental sepsis. Materials and methods: Fifty Wistar rats were divided into 5 groups (n = 10): negative control (laparotomy), CLP, treatment groups including the combination of DDWs (15 and 30 ppm) and ML (100 mg/kg b.w) and indomethacin. At 24 h after CLP induction, lipid peroxidation (LP), glutathione (GSH), glutathione in S-transferases (GST), ferric reducing ability of plasma (FRAP), myeloperoxidase (MPO), prostaglandin E2 (PGE2), and COX-2 expression were determined in the plasma and liver tissues. Results: Compared with the CLP group, the administration of DDWs and ML significantly (p  0.05) differences were observed regarding GST, ALP and bilirubin levels. Our results also proved the synergistic anti-inflammatory activities of the DDWs and ML. The anti-inflammatory effects of the DDWs and ML were confirmed by histopathological studies. Discussion and conclusions: The combination of DDWs and ML exerted synergistic anti-inflammatory activity against CLP-induced sepsis possibly through modulating oxidative stress/antioxidant parameters
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