Browsing by Author "Hurd, Peter L."

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    Damage-induced alarm cues influence lateralized behaviour but not the relationship between behavioural and habenular asymmetry in convict cichlids (Amatitlania nigrofasciata)
    (2017) Moscicki, Michele; Hurd, Peter L.
    Cerebral lateralization, the partitioning of functions into a certain hemisphere of the brain, is ubiquitous among vertebrates. Evidence suggests that the cognitive processing of a stimulus is performed with a specific hemisphere depending in part upon the emotional valence of the stimulus (i.e. whether it is appetitive or aversive). Recent work has implicated a predominance of right-hemisphere processing for aversive stimuli. In fish with laterally placed eyes, the preference to view an object with a specific eye has been used as a proxy for assessing cerebral lateralization. The habenula, one of the most well-known examples of an asymmetrical neural structure, has been linked to behavioural asymmetry in some fish species. Here, we exposed convict cichlid fish (Amatitlania nigrofasciata) to both a social and non-social lateralization task and assessed behavioural lateralization in either the presence or absence of an aversive stimulus, damage-induced alarm cues. We also assessed whether behavioural asymmetry in these tests was related to asymmetry of the habenular nuclei. We found that when alarm cues were present, fish showed increased left-eye (and by proxy, right hemisphere) preference for stimulus viewing. In addition, females, but not males, showed stronger eye preferences when alarm cues were present. We did not find a relationship between behavioural lateralization and habenular lateralization. Our results conflict with previous reports of concordance between behavioural and habenular lateralization in this fish species. However, our results do provide support for the hypothesis of increased right-hemisphere use when an organism is exposed to aversive stimuli.
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    Lateralized behaviour of a non-social cichlid fish ( Amatitlania nigrofasciata) in a social and a non-social environment
    (2011) Moscicki, Michele; Reddon, Adam R.; Hurd, Peter L.
    Cerebral lateralization, the partitioning of cognitive function preferentially into one hemisphere of the brain, is a trait ubiquitous among vertebrates. Some species exhibit population level lateralization, where the pattern of cerebral lateralization is the same for most members of that species; however, other species show only individual level lateralization, where each member of the species has a unique pattern of lateralized brain function. The pattern of cerebral lateralization within a population and an individual has been shown to differ based on the stimulus being processed. It has been hypothesized that sociality within a species, such as shoaling behaviour in fish, may have led to the development and persistence of population level lateralization. Here we assessed cerebral lateralization in convict cichlids ( Amatitlania nigrofasciata), a species that does not shoal as adults but that shoals briefly as juveniles. We show that both male and female convict cichlids display population level lateralization when in a solitary environment but only females show population level lateralization when in a perceived social environment. We also show that the pattern of lateralization differs between these two tasks and that strength of lateralization in one task is not predictive of strength of lateralization in the other task.
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    Sex, boldness and stress experience affect convict cichlid, Amatitlania nigrofasciata, open field behaviour
    (2015) Moscicki, Michele; Hurd, Peter L.
    How an organism deals with stressors is an integral component of survival. Recent research has shown that differences in a well-studied personality axis in fish, the shy–bold axis, relate to stress-coping behaviours. Bold fish tend to cope in a proactive manner (e.g. fighting) while shy fish cope more reactively (e.g. freezing). Because bold fish behave in a more risk-prone manner, it is likely that they encounter more stressors on average than shy fish. Greater exposure to stressful conditions may result in bold fish being less behaviourally sensitive to stressors (i.e. stress resilience). To investigate the idea of stress exposure leading to resilience, we examined whether fish personality (i.e. more bold or shy) affected anxiety-related behaviour in an open field task after fish had been exposed to a net-chasing stressor. We investigated open field behaviour in the presence and absence of a stressor (i.e. damage-induced alarm cues) to determine whether bolder fish would cope differently with a stressor than shy fish after recent stress exposure of a different type. Furthermore, we examined whether asymmetry in the habenula, an asymmetrical nucleus related to behavioural responses to stress and anxiety, is related to behaviour in the presence of stressors. We found no relationship between habenular asymmetry and behaviour in the open field. Net chasing increased activity in the open field for both sexes. We found an interaction between stress exposure and freezing behaviour in females but not in males. When females were not net-chased, shyer females showed a decrease in freezing behaviour when exposed to alarm cues, whereas bolder females showed no change in behaviour. When females were net-chased, there was no difference in freezing behaviour between bolder and shyer fish. We suggest that different parental care roles in this species lead to differential perceptions of the threat of stress between the sexes.
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    Submerged plus maze: a novel test for studying anxiety-like behaviour in fish
    (2019) Hope, Brittany V.; Hamilton, Trevor; Hurd, Peter L.
    The elevated plus maze is a prominent and well-documented test for studying anxiety in rodents. Fish are becoming more prevalent in studies of anxiety, yet the elevated plus maze has not been adapted and validated for fish. In the present study, we created an aquatic version of the elevated plus maze called the ‘submerged plus maze,’ which is shaped like a plus symbol with four arms alternating between black and transparent walls. We used convict cichlid fish (Amatitlania nigrofasciata) and administered diazepam to validate the apparatus for studying anxiety-like behaviour. After diazepam exposure, fish spent more time in and entered more open arms than after vehicle exposure, consistent with the effect of benzodiazepines on rodents in the elevated plus maze. The submerged plus maze maintains construct validity for testing anxiety in convict cichlid fish.
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    The submerged plus maze as an assay for studying anxiety-like behaviour in fish
    (2019) Hope, Brittany V.; Hamilton, Trevor; Hurd, Peter L.
    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.
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    Zebrafish (danio rerio) shoaling in light and dark conditions involves a complex interplay between vision and lateral line
    (2023) Chaput, Shayna; Burggren, Warren; Hurd, Peter L.; Hamilton, Trevor
    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.