Chemical communication of predation risk has evolved multiple times in fish species, with conspecific alarm substance (CAS) being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish are captured by a predator and elicits neurobehavioural adjustments in conspecifics which increase the probability of avoiding predation. As such, CAS is a partial predator stimulus, eliciting risk assessment‐like and avoidance behaviours and disrupting the predation sequence. The present paper reviews the distribution and putative composition of CAS in fish and presents a model for the neural processing of these structures by the olfactory and the brain aversive systems. Applications of CAS in the behavioural neurosciences and neuropharmacology are also presented, exploiting the potential of model fish [e.g., zebrafish Danio rerio, guppies Poecilia reticulata, minnows Phoxinus phoxinus) in neurobehavioural research.

Chemical communication of predation risk has evolved multiple times in fish species, with the conspecific alarm substance (CAS) contemporaneously being the most well understood mechanism. CAS is released after epithelial damage, usually when prey fish is captured by a predator, and elicits neurobehavioral adjustments in conspecifics which increase the probability of avoiding predation. As such, CAS is a partial predator stimulus, eliciting risk assessment-like and avoidance behaviors, and disrupting the predator sequence. The present paper reviews the distribution and putative composition of CAS in fish, and presents a model for the neural processing of these structures by the olfactory and the brain aversive systems. Applications of CAS in the behavioral neurosciences and neuropharmacology are also presented, exploiting the potential of model fish (e.g., zebrafish, guppies, minnows) on neurobehavioral research.

Chrysin (5,7-dihydroxyflavone), a nutraceutical flavonoid present in diverse plants, has a backbone structure shared with the flavone backbone, with additional hydroxyl groups that confers its antioxidant properties and effects at the GABAA receptor complex. However, whether these effects are due to the hydroxyl groups is unknown. Here we report the effects of chrysin or the flavone backbone (1 mg/kg) in rats subjected to the elevated plus-maze and the locomotor activity test, as well as in the zebrafish evaluated in light/dark model. Chrysin, but not flavone, increased entries and time in the open arms of the elevated plus-maze, as well as time on white compartment of the light/dark model in zebrafish. These effects were comparable to diazepam, and were devoid of motor effects in both tests, as well as in the locomotor activity test. On the other hand, flavone decreased risk assessment in the light/dark test but increased rearing in the locomotor activity test in rats, suggesting effects threat information gathering; important species differences suggest new avenues of research. It is suggested that the specific effects of chrysin in relation to flavone include more of a mechanism of action in which in addition to its action at the GABAA/benzodiazepine receptor complex also could be involved its free radical scavenging abilities, which require specific research.

The 1990s were marked as the Decade of the Brain, in response to rapidly increasing interest, by lay audience and scientists alike, on the study of neuroscience (Herculano-Houzel, 2002). From this decade onward, neuroscience gained prominence in the general public; despite this increased interest, however, a decline in the interest of young people in pursuing scientific careers in general and a widespread scientific ignorance in the general populace were observed worldwide in the last 30 years (Gouw et al., 2016; National Academies of Sciences, Engineering, and Medicine, 2016;Osborne et al., 2003). In this context, outreach programs which promote positive and favorable attitudes toward (neuro)science and (neuro)scientists, as well as a generally favorable attitude toward learning science, is an emerging matter of concern (Sperduti et al., 2012). Attitudes are important affective-motivational components of science education which include "the feelings, beliefs and values held about an object that may be the enterprise of science, school science, the impact of science on society or scientists themselves" (Dekker et al., 2012;

The Open Practical Laboratory in the Neurosciences is an intervention that seeks to improve the knowledge of the neurosciences by elementary school students and to promote better attitudes in relation to neuroscience, science in general, and scientists. It consists in practical and demonstration activitities on the theme of the neurosciences. This intervention strategy was applied in four public schools in a municipality in Southeastern Pará, Brazil characterized by low performance in educational reviews in Brazil. The intervention improved students’ knowledge about the neurosciences, and promoted better attitudes in relation to science and scientists, in comparison to students which did not go through the intervention. Results suggest that scientific outreach strategies can produce results beyond immediate increases in knowledge, promoting better attitudes in relation to science.

Chrysin (5,7-dihydroxyflavone), a flavonoid present in diverse plants, has a backbone structure shared with the basic structure of the flavones, with additional hydroxyl groups that confers its antioxidant properties and effects at the GABAA receptor complex. However, whether these effects are due to the hydroxyl groups is unknown. Here we report the effects of chrysin or the flavone backbone (1 mg/kg) on rat behavior in the elevated plus-maze (EPM) and a locomotor activity test (LAT), as well as in the zebrafish light/dark test (LDT). Chrysin, but not flavone, increased entries and time in the open arms of the EPM, as well as time on white in the zebrafish LDT. These effects were comparable to diazepam, and were devoid of motor effects in both tests, as well as in the rat LAT. On the other hand, flavone increased risk assessment in the zebrafish LDT and rat EPM, suggesting effects threat information gathering; important species differences suggest new avenues of research. It is suggested that the specific effects of chrysin in relation to flavone are due to its free radical scavenging abilities and/or its action at the GABA A /benzodiazepine receptor complex. Preprint: https://doi.org/10.1101/575514; Data and scripts: https://github.com/lanec-unifesspa/chrysin 1/16 29 behavior. The basic flavone moiety has an hydrogen bond donor site, lipophilic pockets, 30 and an electron rich site (Marder and Paladini, 2002); this last is thought to be 31 important for the binding of both flavonoids and 1,4-benzodiazepines to the central 32 benzodiazepine (BZD) site at GABA A receptors (Marder and Paladini, 2002). Since the 33 chrysin hydroxyl groups are located in one region of the flavone basic ring that is 34 important for the steric interactions associated with binding, this flavonoid is expected 35 to bind BZD sites with a higher affinity than flavone. As a result, while chrysin is 36 2/16 65 measures in the study.

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