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Introduction: Over the last decades, our understanding of the cognitive, motivational, and neural processes involved in addictive behavior has increased enormously. A plethora of laboratory-based and cross-sectional studies has linked cognitive-behavioral measures to between-subject differences in drinking behavior. However, such laboratory-based studies inevitably suffer from small sample sizes and the inability to link temporal fluctuations in task measures to fluctuations in real-life substance use. To overcome these problems, several existing behavioral tasks have been transferred to smartphones to allow studying cognition in the field. Method: In this narrative review, we first summarize studies that used existing behavioral tasks in the laboratory and self-reports of substance use with ecological momentary assessment (EMA) in the field. Next, we review studies on psychometric properties of smartphone-based behavioral tasks. Finally, we review studies that used both smartphone-based tasks and self-reports with EMA in the field. Results: Overall, studies were scarce and heterogenous both in tasks and in study outcomes. Nevertheless, existing findings are promising and point toward several methodological recommendations: concerning psychometrics, studies show that – although more systematic studies are necessary – task validity and reliability can be improved, for example, by analyzing several measurement sessions at once rather than analyzing sessions separately. Studies that use tasks in the field, moreover, show that power can be improved by choosing sampling schemes that combine time-based with event-based sampling, rather than relying on time-based sampling alone. Increasing sampling frequency can further increase power. However, as this also increases the burden to participants, more research is necessary to determine the ideal sampling frequency for each task. Conclusion: Although more research is necessary to systematically study both the psychometrics of smartphone-based tasks and the frequency at which task measures fluctuate, existing studies are promising and reveal important methodological recommendations useful for researchers interested in implementing behavioral tasks in EMA studies.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to evaluate the effects of HgCl2 exposure in drinking water in pregnant and/or lactating rats and their offspring. Still, it evaluated if the HgCl2 intravenous exposure as well as the renal damage induced by this exposure altered the offspring mercury content. The drinking water (v.o.) HgCl2 exposure protocol was as follows: Female Wistar rats were exposed to HgCl2 (0, 0.2, 0.5, 10 and 50 μg Hg2+/mL) from gestation day 0 until 20 or until the last day of lactation. Every two days, the mercury solutions were changed, food and water intake and rats weight were analyzed. The offspring was killed on gestation day 20 and on the post-natal days 10, 20, 30 and 40. Tissues weight, essential metal homeostasis, mercury content and biochemical parameters were evaluated. Behavioral tasks were carried out on post-natal days 3, 5, 7, 9 and 11 (negative geotaxis test) and 17, 18, 19 and 20 (beaker test). The intravenous (i.v.) HgCl2 exposure protocol was as follows: Female Wistar rats were exposed to HgCl2 (0.5 and 2.5 μmol HgCl2/kg/2 mL) on gestation day 20 and killed 6 h later or on gestation day 18 and killed 48 h later. Hg maternal and fetal distribution and renal damage through histology and biochemical and molecular markers were evaluated. Dams exposed to HgCl2 v.o. presented water intake decreased. The exposure to 50 μg Hg2+/mL caused an increase in relative renal weight. Animals exposed to 10 and 50 μg Hg2+/mL presented an increase in renal and hepatic Cu and Zn levels, respectively, and mercury accumulation (pregnant rats); and, an increase in total thiol and metallothionein renal levels (lactating rats). The offspring only presented an increase in hepatic porfobilinogensynthase activity (fetuses) and in relative renal weight (post-natal day 20). The pregnant rats exposed i.v. to HgCl2 presented the greater mercury accumulation in kidney in both periods analyzed; although 48 h after the exposure the Hg levels were lower than at 6 h. The exposure to 2.5 μmol HgCl2/kg/2 mL caused an increase in serum creatinine levels and in Kim-1 renal expression as well as renal histology alterations. The placental and fetal Hg did not change in both periods analyzed; the increase in fetal organs Hg levels were dose and time dependent. In conclusion, the exposure to low doses of HgCl2 in drinking water caused mild alterations in dams; also the dam organism was able to handle the Hg avoiding offspring damages; probably, this protection is related with the increase on scavenger molecules (metallothionein, for example) during the pregnancy and lactation. Besides, we verified that when dams were exposed intravenously to HgCl2, the developing organisms (fetuses) were unable to excrete/depurate the Hg. / O objetivo deste trabalho foi avaliar os efeitos da exposição ao HgCl2 na água de beber em ratas prenhas e/ou lactantes e sua prole. Ainda, avaliar se a exposição intravenosa ao HgCl2 assim como o dano renal induzido pela mesma altera a deposição de mercúrio na prole. O protocolo de exposição ao HgCl2 na água de beber (v.o.) foi: as ratas Wistar foram expostas ao HgCl2 (0, 0,2, 0,5, 10 e 50 μg Hg2+/mL) do dia zero de gestação até o dia 20 ou até o final da lactação. A cada dois dias, as soluções de mercúrio eram trocadas, a ingestão de comida e água e o peso das ratas eram avaliados. A prole foi sacrificada no dia 20 de gestação e nos dias pós-natal 10, 20, 30 e 40. Foram analisados o peso dos órgãos, a homeostase de metais essenciais, os níveis de mercúrio e parâmetros bioquímicos. As tarefas comportamentais foram realizadas nos dias pós-natal 3, 5, 7, 9 e 11 (teste do geotactismo negativo) e 17, 18, 19 e 20 (teste do beaker). O protocolo de exposição ao HgCl2 intravenoso (i.v.) foi: as ratas Wistar foram expostas ao HgCl2 (0,5 e 2,5 μmol HgCl2/kg/2 mL) no dia 20 de gestação e sacrificadas 6 h após a exposição ou no dia 18 de gestação e sacrificadas 48 h após a exposição. Foram avaliados a distribuição do Hg nos organismos materno e fetal e o dano renal através de histologia e marcadores bioquímicos e moleculares. As mães expostas ao HgCl2 v.o. apresentaram diminuição na ingestão de água; a exposição a dose de 50 μg Hg2+/mL causou aumento no peso relativo de rim. As doses de 10 e 50 μg Hg2+/mL causaram aumento dos níveis renais de Cu e hepáticos de Zn e acúmulo de mercúrio em rins nas gestantes; e aumento nos níveis renais de tióis totais e de metalotioneínas nas lactantes. A prole exposta ao HgCl2 apresentou aumento da atividade hepática da porfobilinogênio sintase em fetos e aumento do peso relativo de rim no dia pós-natal 20. As ratas expostas ao HgCl2 i.v. apresentaram maior acúmulo de mercúrio em rins 6 e 48 h após a exposição; embora a 48 h da exposição, os níveis já haviam diminuído em relação a 6 h. A dose de 2,5 μmol HgCl2/kg/2 mL i.v. causou aumento nos níveis séricos de creatinina, aumento da expressão da proteína Kim-1 e alterações na histologia de rim. Os níveis de Hg placentário e fetal não diminuíram com o passar das horas após a exposição; nos órgãos fetais, os níveis de Hg apresentaram aumento dependente da dose e do tempo. Em conclusão, a exposição a baixas doses de HgCl2 na água de beber causou alterações brandas nas mães; e o organismo materno parece ter metabolizado o Hg, evitando danos à prole; provavelmente esta proteção está relacionada ao aumento dos níveis de moléculas detoxificantes (metalotioneínas, por exemplo) durante o período gestacional e lactacional. Ainda, verificamos a incapacidade dos organismos em desenvolvimento (fetos) em excretar/depurar os íons Hg quando as mães foram expostas intravenosamente ao metal.

Self-regulation, the ability to guide behavior according to one’s goals, plays an integral role in understanding loss of control over unwanted behaviors, for example in alcohol use disorder (AUD). Yet, experimental tasks that measure processes underlying self-regulation are not easy to deploy in contexts where such behaviors usually occur, namely outside the laboratory, and in clinical populations such as people with AUD. Moreover, lab-based tasks have been criticized for poor test–retest reliability and lack of construct validity. Smartphones can be used to deploy tasks in the field, but often require shorter versions of tasks, which may further decrease reliability. Here, we show that combining smartphone-based tasks with joint hierarchical modeling of longitudinal data can overcome at least some of these shortcomings. We test four short smartphone-based tasks outside the laboratory in a large sample (N = 488) of participants with AUD. Although task measures indeed have low reliability when data are analyzed traditionally by modeling each session separately, joint modeling of longitudinal data increases reliability to good and oftentimes excellent levels. We next test the measures’ construct validity and show that extracted latent factors are indeed in line with theoretical accounts of cognitive control and decision-making. Finally, we demonstrate that a resulting cognitive control factor relates to a real-life measure of drinking behavior and yields stronger correlations than single measures based on traditional analyses. Our findings demonstrate how short, smartphone-based task measures, when analyzed with joint hierarchical modeling and latent factor analysis, can overcome frequently reported shortcomings of experimental tasks.