Tribal brains in the global village: Deeper roots of the pandemic

I briefly recap the messages of the target article by Wiebers & Feigin (2020) and the accompanying peer commentaries about what we learn from the COVID-19 pandemic. Using the rapid evolution of viruses as an example of the importance of prevention, I explore why it is difficult for our species to foresee and prevent unintended global changes resulting from human activity. I end with a discussion about the long-term future, the ultimate problem inherent in our current mindset and the structure of our economy: growth

Learning, memory, cognition, and the question of sentience in fish

Evolutionarily conserved features have been demonstrated at many levels of biological organization across a variety of species. Evolutionary conservation may apply to complex behavioral phenomena too. It is thus not inconceivable that a form of sentience does exist even in the lowest order vertebrate taxon, the teleosts. How similar it is to human sentience in its level of complexity or in its multidimensional features is a difficult question, especially from an experimental standpoint, given that even the definition of human sentience is debated. Woodruff attempts a Turing-like test of fish sentience, and lists numerous neuroanatomic, neurophysiological and behavioral similarities between fish and humans. In this commentary, I add to these similarities by discussing empirical findings showing complex forms of mental representation in fish. At the same time, I note that without a more thorough understanding of human sentience and more data on similarities as well as differences between fish and mammals, the final conclusion may have to wait

Sentience: All or none or matter of degree?

The question of whether fish feel pain is muddied by anthropomorphic thinking. Comparing biological phenomena in two species should be informed by the criteria for good animal models: face validity, construct validity and predictive validity. Viewed through this lens, we argue that fish do feel pain and may possess some level of sentience. Evolutionary relatedness, hence similarities and differences between species (fish and humans in this case), are not about black vs. white but about shades of grey

The Role of Body Surface Area in Quantity Discrimination in Angelfish (Pterophyllum scalare)

Although some fish species have been shown to be able to discriminate between two groups (shoals) of conspecifics differing in the number of members, most studies have not controlled for continuous variables that covary with number. Previously, using angelfish (Pterophyllum scalare) we started the systematic analysis of the potential influence of such continuous variables, and found that they play different roles in shoal discrimination depending on whether large (≥ 4 fish) or small (<4 fish) shoals were contrasted. Here, we examine the potential role of the overall body surface area of stimulus fish in shoal preference, a prominent variable not yet examined in angelfish. We report that both when numerically large (5 versus 10 fish) and when small (2 versus 3 fish) shoals were contrasted, angelfish were unable to discriminate the numerically different shoals as long as the surface area of the contrasted shoals was equated. Thus, we conclude that body surface may be an important continuous variable in shoal discrimination. This conclusion was further supported by the analysis of preference when shoals of the same numerical size but different body surface area were contrasted. We found subjects to spend significantly more time close to the shoals with the greater overall surface area. Last, we conducted an experiment in which we simultaneously controlled a set of continuous variables, including overall surface area, and found angelfish to use the number of shoal members as a cue only in large shoal contrasts but not in small shoal contrasts. This result suggests the potential existence of different processing systems for large and small numbers in fish

The zebrafish as a promising tool for modeling human brain disorders: A review based upon an IBNS Symposium

The zebrafish represents an excellent compromise between system complexity and practical simplicity, features that make it useful for modeling and mechanistic analysis of complex brain disorders. Also promising are screens for psychoactive drugs with effects on larval and adult zebrafish behavior. This review, based upon a recent symposium held at the 2016 IBNS Congress, provides different perspectives on how the zebrafish may be utilized to advance research into human central nervous system disorders. It starts with a discussion on an important bottleneck in zebrafish research, measuring the behavior of this species (specifically shoaling), and continues with examples on research on autism spectrum disorder in larval zebrafish, on screening natural products for compounds with psychoactive properties in adult zebrafish, and on the development of a zebrafish model of fetal alcohol spectrum disorders. By providing information on a broad spectrum of brain disorders, experimental methods, and scientific approaches using both larval and adult zebrafish, the review is intended to showcase this underutilized laboratory species for behavioral neuroscience and psychopharmacology research