RESUMEN
Systematic reviews are used to collect relevant literature to answer a research question in a way that is clear, thorough, unbiased and reproducible. They are implemented as a standard method in the domain of food safety to obtain a literature overview on the state-of-the-art research related to food safety topics of interest. A disadvantage to systematic reviews, however, is that this process is time-consuming and requires expert domain knowledge. The work reported here aims to reduce the time needed by an expert to screen all possible relevant articles by applying machine learning techniques to classify the articles automatically as either relevant or not relevant. Eight different machine learning algorithms and ensembles of all combinations of these algorithms were tested on two different systematic reviews on food safety (i.e. chemical hazards in cereals and leafy greens). The results showed that the best performance was obtained by an ensemble of naive Bayes and a support vector machine, resulting in an average decrease of 32.8% in the amount of articles the expert has to read and an average decrease in irrelevant articles of 57.8% while keeping 95% of the relevant articles. It was concluded that automatic classification of the literature in a systematic literature review can support experts in their task and save valuable time without compromising the quality of the review.
RESUMEN
Fear and trauma generate some of the longest-lived memories. Despite the corresponding need to understand how such memories can be attenuated, the underlying brain circuits remain unknown. Here, combining viral tracing, neuronal activity mapping, fiber photometry, chemogenetic and closed-loop optogenetic manipulations in mice, we show that the extinction of remote (30-day-old) fear memories depends on thalamic nucleus reuniens (NRe) inputs to the basolateral amygdala (BLA). We found that remote, but not recent (1-day-old), fear extinction activates NRe-to-BLA inputs, which become potentiated upon fear reduction. Furthermore, both monosynaptic NRe-to-BLA and total NRe activity increase shortly before freezing cessation, suggesting that the NRe registers and transmits safety signals to the BLA. Accordingly, pan-NRe and pathway-specific NRe-to-BLA inhibition impairs, whereas their activation facilitates, remote fear extinction. These findings identify the NRe as a crucial BLA regulator for extinction and provide the first functional description of the circuits underlying the attenuation of consolidated fear memories.
