Alternative male morphs are found in many species of fishes. These morphs often differ in suites of social behaviours, such as aggression and territoriality, associated with alternative reproductive tactics. Such consistent morph-typical behavioural profiles suggest common differences in underlying neuroendocrine mechanisms. The nonapeptide hormones oxytocin and vasotocin are linked to a wide range of behaviours, including aggression, mating behaviour and social attraction. These behaviours often differ between male morphs, suggesting that nonapeptides may mediate behavioural variation between morphs. We compared two morphs of a West African cichlid, Pelvicachromis pulcher, to test for differences in nonapeptide neuronal phenotypes. P. pulcher exhibit at least four distinct male colour morphs, of which the red and yellow morphs are the most common and have the best-described social and reproductive behaviours. Red males tend towards breeding as harem holders, whereas yellow males breed monogamously or act as satellite males on the territories of red males. Here, we examine nonapeptide-producing neurons in the preoptic area of the hypothalamus in the red and yellow morphs. We found that the more aggressive polygynous red morph has larger parvocellular oxytocin and vasotocin-producing neurons, as well as larger gigantocellular oxytocin neurons, compared to the yellow morph. We did not find any association between the number of oxytocin or vasotocin cells and male morph. Our results suggest that the production of oxytocin and vasotocin in the preoptic area may play a role in determining morph-typical behaviour among P. pulcher males.

Zebrafish (Danio rerio) are widely used in behavioural neuroscience as a model for studying anxiety-like and stress-related behaviours. However, substantial variability exists within and among individuals, influenced by factors such as sex, age, and environmental conditions, making the interpretation of anxiety-related behaviours challenging. Here we characterized longitudinal patterns of stability and variability in anxiety-like behaviours across individual adult zebrafish and assessed whether distinct behavioural profiles emerged over time. Using the novel tank dive test, we tracked anxiety-related behaviours in zebrafish across multiple time points over a 21-week period (90, 120, and 150 days post-fertilization). Behavioural metrics, including time spent in tank zones, swimming velocity, and immobility, were analyzed for age- and sex-related effects, repeatability, and group variation. Results indicated significant changes in anxiety-like behaviours with age, with fish spending more time in the upper zone and displaying increased swimming velocity over time. While no significant sex differences were observed in zone preference, males exhibited greater within-individual variation in time spent in the lower zone, while females demonstrated higher among-individual variation and repeatability over time. Furthermore, zebrafish were classified into high, medium, and low-anxiety groups based on cumulative behavioural scores, revealing stable individual differences in anxiety-like behaviours. These findings highlight the importance of considering age, sex and both intra- and inter-individual variation when interpreting zebrafish behaviour and provide a foundation for future research exploring selective breeding, anxiety level interactions, and pharmacological modulation of anxiety-related phenotypes.

Intracerebral hemorrhage (ICH) along with aggravating factors, such as edema, can raise intracranial pressure (ICP) to pathological levels. Diversion of some cerebrospinal fluid (CSF) and venous blood out of the cranium can limit ICP rises while maintaining cerebral perfusion pressure. Brain tissue itself is widely considered immutable in volume but prone to distortion (e.g., midline shift). However, distal brain regions shrink acutely following ICH in rodents. Tissue contraction arises from cell shrinkage and increased packing density. This “tissue compliance” is hypothesized to be an additional mechanism to limit ICP rises. Here, we examined whether and by how much parenchyma volume reduction occurs in ICH patients. We conducted a retrospective analysis on computed tomography (CT) scans of 96 ICH patients (average age 63.8 years old, 55

This study investigated the effects of anxiogenic and anxiolytic drugs on zebrafish (Danio rerio) behaviour using a modified novel tank dive test with higher walls and a narrower depth. Zebrafish were administered chondroitin sulfate, beta-carboline, Delta-9-tetrahydrocannabinol (THC), ethanol, and beta-caryophyllene, and their behaviours were evaluated for geotaxis, swimming velocity, and immobility. Both anxiogenic and anxiolytic compounds generally increased bottom-dwelling behaviour, suggesting that the tank's modified dimensions significantly influence zebrafish responses. EC50 values for ethanol showed a lower threshold for velocity reduction compared to zone preference. Chondroitin sulfate uniquely caused a sex-specific increase in male swimming velocity, whereas no other sex-differences were observed with any compound. Interestingly, the presence of drug-treated fish did not alter the behaviour of observer fish, suggesting limited social buffering effects. The findings underscore the complexity of zebrafish behavioural phenotypes and highlight the need for considering tank dimensions and multiple behavioural parameters to accurately assess the effects of anxiety-modulating drugs. This study demonstrates the utility of the modified novel tank dive test in providing nuanced insights into the behavioural effects of different pharmacological agents in zebrafish.

We know little about how -or even if in some species - fish shoal in darkness. We hypothesized that 'dark shoaling' occurs in zebrafish and therefore must depend upon lateral line sensory input. Shoaling in groups of five adult zebrafish was analyzed with motion tracking software. We measured average inter-individual distance, time near the arena wall (thigmotaxis zone) and total distance traveled under normal room light, and in near -complete darkness (infrared light at 850 nm). These observations were repeated in fish treated with cobalt chloride (CoCl2), which ablates lateral line function. In untreated controls, dark shoaling was reduced compared to in light, but nonetheless still present. Elimination of lateral line sensory input by CoCl2 treatment similarly reduced, but did not eliminate, shoaling under both light and dark. Our findings indicate that normal zebrafish shoaling in light or dark requires both visual and lateral line inputs, with neither alone sufficient for normal shoaling.

The fraternal birth order effect (FBOE) is the phenomenon whereby the probability that a man has a same-sex sexual orientation in adulthood increases with each biological older brother. Several studies have found evidence that the FBOE is limited to right-handed men, and left-handed men do not show an FBOE. Recent debates about the appropriate methods for quantifying the FBOE center on distinguishing the FBOE from other effects, such as the female fecundity effect (FFE), whereby mothers more prone to bearing gay sons are also more fecund. The FBOE and FFE are confounded in that a real FFE will result in data consistent with the FBOE under some analyses. Here, we applied some recent proposed analytic methods for the FBOE to the property of handedness. A straightforward application of Khovanova's technique to the binary trait of handedness yielded support for a fraternal birth order effect consistent with the maternal immune hypothesis, in that the ratios of handedness differed between men with one older brother only, and men with one younger brother only, while no such effect was seen in women. This effect was not seen, however, when the confounding effects of parental age were controlled for. Models including factors to simultaneously test multiple posited effects find significant female fecundity effects, as well as paternal age and birth order effects on handedness in men, but no FBOE. The effects seen in women were different, with no fecundity or parental age effects, but birth order and sex of older siblings had effects. We conclude, based on this evidence, that many of the factors thought to contribute to sexual orientation in men may also have an influence on handedness, and further note that parental age is a potential confound which may be overlooked by some analyses of the FBOE.

Video games are popular and ubiquitous aspects of human culture, but their relationships to psychological and neurophysiological traits have yet to be analyzed in social-evolutionary frameworks. We examined the relationships of video game usage, motivations, and preferences with autistic and schizotypal traits and two aspects of neurophysiology, reaction time and targeting time. Participants completed the Autism Quotient, Schizotypal Personality Questionnaire, a Video Game Usage Questionnaire, and two neurophysiological tasks. We tested in particular the hypotheses, motivated by theory and previous work, that: (1) participants with higher autism scores would play video games more, and participants with higher schizotypy scores would play video games less; and (2) autism and positive schizotypy would be associated with opposite patterns of video game use, preferences and motivations. Females, but not males, with higher autism scores played more video games, and exhibited evidence of relatively male-typical video game genre preferences and motivations. By contrast, positive schizotypy was associated with reduced video game use in both genders, for several measures of game use frequency. In line with previous findings, males played video game more than females did overall, preferred action video games, and exhibited faster reaction and targeting times. Females preferred Puzzle and Social Simulation games. Faster reaction and targeting times were associated with gaming motives related to skill development and building behavior. These findings show that gaming use and patterns reflect aspects of psychology, and gender, related to social cognition and imagination, as well as aspects of neurophysiology. More generally, the results suggest that video game use is notably affected by levels of autistic and schizotypal traits, and that video games may provide an evolutionarily novel medium for imaginative play in which immersive play experiences can be decoupled from social interaction.

Mutations affecting the synaptic-scaffold gene SHANK3 represent the most common genetic causes of autism with intellectual disability, accounting for about 1-2% of cases. Rare variants of this gene have also been associated with schizophrenia, and its deletion results in the autistic condition known as Phelan–McDermid syndrome. Despite the importance of SHANK3 as a paradigmatic gene mediating neurodevelopmental disorders, its psychological effects in nonclinical populations have yet to be studied. We genotyped the nonsynonymous, functional SHANK3 SNP rs9616915 in a large population of typical individuals scored for autism spectrum traits (the Autism Quotient, AQ) and schizotypy spectrum traits (the Schizotypal Personality Questionnaire, SPQ-BR). Males, but not females, showed significant genotypic effects for the SPQ-BR subscale associated with speech and language: Odd Speech. These findings, in conjunction with animal model studies showing vocalization and auditory effects of SHANK3 mutations, and studies indicating severe language alterations and speech-associated white matter tract abnormalities in Phelan–McDermid syndrome, suggest that SHANK3 differentially affects the development and expression of human language and speech. Imaging genetic and speech-language studies of typical individuals carrying different genotypes of rs9616915 should provide novel insights into the neurological and psychological bases of speech and language alterations among individuals with SHANK3 mutations and Phelan–McDermid syndrome.

How is cognitive empathy related to sociality, imagination, and other psychological constructs? How is it altered in disorders of human social cognition? We leveraged a large data set (1,168 students, 62% female) on the Reading the Mind in the Eyes test (RMET), the Autism Quotient (AQ), and the Schizotypal Personality Questionnaire (SPQ-BR) to test the hypotheses that the RMET, as a metric of cognitive empathy, reflects mainly social abilities, imagination, or both. RMET showed the expected female bias in performance, though only for eyes that expressed emotions and not for neutral expressions. RMET performance was significantly, and more strongly, associated with the AQ and SPQ subscales that reflect aspects of imagination (AQ-Imagination and SPQ-Magical Ideation) than aspects of social abilities (AQ-Social, AQ-Communication, and SPQ-Interpersonal subscales). These results were confirmed with multiple regression analysis, which also implicated increased attention (AQ-Attention Switching and, marginally non-significantly, AQ-Attention to Detail) in RMET performance. The two imagination-related correlates of RMET performance also show the strongest sex biases for the AQ and SPQ: male biased in AQ-Imagination, and female biased in SPQ-Magical Ideation, with small to medium effect sizes. Taken together, these findings suggest that cognitive empathy, as quantified by the RMET, centrally involves imagination, which is underdeveloped (with a male bias) on the autism spectrum and overdeveloped (with a female bias) on the schizotypy spectrum, with optimal emotion-recognition performance intermediate between the two. The results, in conjunction with previous studies, implicate a combination of optimal imagination and focused attention in enhanced RMET performance.

Recent advancements in portable computer devices have opened new avenues in the study of human cognition outside research laboratories. This flexibility in methodology has led to the publication of several electroencephalography studies recording brain responses in real-world scenarios such as cycling and walking outside. In the present study, we tested the classic auditory oddball task while participants moved around an indoor running track using an electric skateboard. This novel approach allows for the study of attention in motion while virtually removing body movement. Using the skateboard auditory oddball paradigm, we found reliable and expected standard-target differences in the P3 and MMN/N2b event-related potentials. We also recorded baseline electroencephalography activity and found that, compared to this baseline, alpha power is attenuated in frontal and parietal regions during skateboarding. In order to explore the influence of motor interference in cognitive resources during skateboarding, we compared participants' preferred riding stance (baseline level of riding difficulty) versus their non-preferred stance (increased level of riding difficulty). We found that an increase in riding difficulty did not modulate the P3 and tonic alpha amplitude during skateboard motion. These results suggest that increases in motor demands might not lead to reductions in cognitive resources as shown in previous literature.

Studying environmental sex determination (ESD) in cichlids provides a phylogenetic and comparative approach to understand the evolution of the underlying mechanisms, their impact on the evolution of the overlying systems, and the neuroethology of life history strategies. Natural selection normally favors parents who invest equally in the development of male and female offspring, but evolution may favor deviations from this 50:50 ratio when environmental conditions produce an advantage for doing so. Many species of cichlids demonstrate ESD in response to water chemistry (temperature, pH, and oxygen concentration). The relative strengths of and the exact interactions between these factors vary between congeners, demonstrating genetic variation in sensitivity. The presence of sizable proportions of the less common sex towards the environmental extremes in most species strongly suggests the presence of some genetic sex-determining loci acting in parallel with the ESD factors. Sex determination and differentiation in these species does not seem to result in the organization of a final and irreversible sexual fate, so much as a life-long ongoing battle between competing male- and female-determining genetic and hormonal networks governed by epigenetic factors. We discuss what is and is not known about the epigenetic mechanism behind the differentiation of both gonads and sex differences in the brain. Beyond the well-studied tilapia species, the 2 best-studied dwarf cichlid systems showing ESD are the South American genus Apistogramma and the West African genus Pelvicachromis. Both species demonstrate male morphs with alternative reproductive tactics. We discuss the further neuroethology opportunities such systems provide to the study of epigenetics of alternative life history strategies and other behavioral variation.

A fit animal must develop testes or ovaries, with brain and physiology to match. In species with alternative male morphs this coordination of development across tissues operates within sexes as well as between. For Pelvicachromis pulcher, an African cichlid in which early pH exposure influences both sex and alternative male morph, we sequence both copies of aromatase (cyp19a1), a key gene for sex determination. We analyze gene expression and epigenetic state, comparing gonad and brain tissue from females, alternative male morphs, and fry. Relative to brain, we find elevated expression of the A-copy in the ovaries but not testes. Methylation analysis suggests strong epigenetic regulation, with one region specifying sex and another specifying tissue. We find elevated brain expression of the B-copy with no sex or male morph differences. B-copy methylation follows that of the A-copy rather than corresponding to B-copy expression. In 30-day old fry, we see elevated B-copy expression in the head, but we do not see the expected elevated A-copy expression in the trunk that would reflect ovarian development. Interestingly, the A-copy epialleles that distinguish ovaries from testes are among the most explanatory patterns for variation among fry, suggesting epigenetic marking of sex prior to differentiation and thus laying the groundwork for mechanistic studies of epigenetic regulation of sex and morph differentiation.

Early life experience may have lifelong influences on an individual's behaviour in ways that are either adaptive or maladaptive depending in part on whether these early experiences accurately foreshadowed conditions in later life. Stress coping style is one example of a suite of behaviours, or personality traits, that may be influenced by early exposure to stressful stimuli. Here we examine the effect of developmental stress exposure on behavioural syndromes in adult convict cichlids, Amatitlania nigrofasciata. We found that early life stress did not exert significant effects on personality traits in adulthood at the individual level, but that this stress exposure prevented the formation of an exploration-boldness syndrome that was present in the unstressed population. These results suggest that an exploration -boldness syndrome is present in this species in the absence of stress-related environmental constraints. However, greater plasticity may be selected for in response to early life cues that reflect high predator pressure. (C) 2020 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

The paternally expressed gene SNORD116 encodes a set of short nucleolar RNAs that affect the expression of hundreds of other genes via epigenetic interactions. Lack of expression for SNORD116 has been implicated in major phenotypes of Prader-Willi Syndrome (PWS). Rates of psychosis and autism spectrum disorders are greatly increased in PWS, but the genetic and epigenetic causes of these increases remain unknown. We genotyped a large population of typical individuals for five SNPs within SNORD116 and phenotyped them for variation in schizotypal and autism spectrum traits. SNORD116 SNP and haplotype variation mediated variation exclusively in the Schizotypal Personality Questionnaire - Ideas of Reference subscale, which reflects variation in aspects of paranoia. The effect was restricted to females. SNORD116 represents, in addition to UBE3A and NDN-MAGEL2, a third, independent locus in the 15q11-q13 imprinted region that preferentially or exclusively affects levels of paranoia. This convergent pattern may reflect a common neural pathway affected by multiple genes, or an effect of interactions between the imprinted loci.

The elevated plus maze is a commonly used and well-validated test of anxiety-related behaviour in rodents. The use of fish in behavioural neuroscience paradigms is increasing, necessitating an equivalent test for studying anxiety-like behaviour in fish. Because behaviour in the elevated plus maze is driven by aversion to open space, the submerged plus maze described here uses transparent walls to elicit similar behaviour in fish. The tendency of fish to explore or avoid the sections of the maze containing transparent walls is used as proxy for anxiety level. This submerged plus maze was designed and validated for convict cichlid (Amatitlania nigrofasciata) fish.

The maternally expressed imprinted gene UBE3A has been implicated in autism, schizophrenia and psychosis. The phenotype of Angelman syndrome, caused by loss of UBE3A expression, involves autism spectrum traits, while Prader-Willi syndrome, where the genotype of maternal disomy increases dosage of UBE3A, shows high penetrance for the development of psychosis. Maternal duplications of the 15q11-q13 chromosome region that overlap the imprinted region also show an association with schizophrenia, further implying a connection between increased dosage of UBE3A and the development of schizophrenia and psychosis. We phenotyped a large population of typical individuals for autism spectrum and schizotypal traits and genotyped them for a set of SNPs in UBE3A. Genetic variation of rs732739, an intronic SNP tagging a large haplotype spanning nearly the entire range of UBE3A, was significantly associated with variation in total schizotypy. Our results provide an independent line of evidence, connecting the imprinted UBE3A gene to the schizophrenia spectrum.

The relationships of spirituality with human social cognition, as exemplified in autism spectrum and schizophrenia spectrum cognitive variation, remain largely unstudied. We quantified non-clinical levels of autism spectrum and schizotypal spectrum traits (using the Autism Quotient and the Schizotypal Personality Questionnaire-Brief Revised) and dimensions of spirituality (using the Hardt Spirituality Questionnaire) in a large sample of undergraduate students. We tested in particular the hypothesis, based on the diametrical model of autism and psychosis, that autism should be negatively associated, and positive schizotypal traits should be positively associated, with spirituality. Our primary findings were threefold. First, in support of the diametric model, total Spirituality score was significantly negatively correlated with total Autism Quotient score, and significantly positively correlated with Positive Schizotypal traits (the Schizotypal Personality Cognitive-Perceptual subscale), as predicted. Second, these associations were driven mainly by opposite patterns regarding the Search for Meaning Spirituality subscale, which was the only subscale that was significantly negatively associated with autism, and significantly positively associated with Positive Schizotypal traits. Third, Belief in God was positively correlated with Positive Schizotypal traits, but was uncorrelated with autism traits. The opposite findings for Search for Meaning can be interpreted in the contexts of well-supported cognitive models for understanding autism in terms of weak central coherence, and understanding Positive Schizotypal traits in terms of enhanced salience.