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The nematode C. elegans is a multicellular model organism to study the neuronal-basis of behaviour. C. elegans demonstrates an innate response to swim towards the cathode in the presence of a DC electric field(EF), a behaviour known as “electrotaxis”. We examined mutants affecting sensory and dopaminergic neurons and found that these mutants moved with reduced speed with intermittent pauses, abnormal turning, and slower body bend. A similar phenotype was observed in worms treated with neurotoxins 6-OHDA, MPTP and rotenone. Pre-exposing worms to a known neuroprotective compound acetaminophen could suppress the effects of neurotoxin on movement. Further, this study demonstrates that dopamine and the D2-type dopamine receptor are necessary to modulate electrotactic movements in worms. A reduction in extracellular dopamine leads to a significant increase in the swimming speed as judged by the analysis of bas-1(dopa decarboxylase) and cat-1(VMAT) mutants. The dopamine transporter dat-1 acts genetically downstream of bas-1 and cat-1 since dat-1 mutants efficiently suppress bas-1 and cat-1 phenotypes. We also found that DOP-3(D2-type receptor) acts as the sole receptor for dopamine-mediated regulation of electrotaxis. Interestingly, we found that prolonged exposure to EF resulted in a gradual decline in the swimming speed such that animals were 40% slower at the end of ten minutes exercise period. This change is mediated by DOP-3 since dop-3 mutants continue to swim at the initial speed and don’t slow down. This conclusion is supported by the analysis of animals treated with Heloperidol(D2 antagonist) and SKF38393(D1 agonist). Overall, our work demonstrates that D2 receptor-mediated neuronal signalling is required to restrict muscle activity not only during the initial phase of electrotaxis swimming but also for the entire duration of the assay. We suggest that such a role of dopamine signalling might serve as an important and conserved mechanism to limit muscle overuse during prolonged physical exercise. / Thesis / Doctor of Science (PhD)

Previous research on mind wandering has used subjective verbal reports as a means to acquire the frequency and rate of its occurrence. I proposed the use of eye movements as an objective measure of mind wandering while participants attempted a reading task. Participants were placed in a self-classified probe-caught mind wandering paradigm while their eye movements were recorded. They were randomly probed every 2-3 minutes and were required to indicate whether their mind had been wandering before they were allowed to continue reading. The overall pattern showed that eye movement behaviour was slower and less frequent when participants reported mind wandering episodes, with duration and frequency of within-word regressions reaching levels of statistical significance. It may be that the cognitive processes that normally guide eye movements during reading exert less control during mind wandering episodes. Other implications and limitations are discussed.

Previous research on mind wandering has used subjective verbal reports as a means to acquire the frequency and rate of its occurrence. I proposed the use of eye movements as an objective measure of mind wandering while participants attempted a reading task. Participants were placed in a self-classified probe-caught mind wandering paradigm while their eye movements were recorded. They were randomly probed every 2-3 minutes and were required to indicate whether their mind had been wandering before they were allowed to continue reading. The overall pattern showed that eye movement behaviour was slower and less frequent when participants reported mind wandering episodes, with duration and frequency of within-word regressions reaching levels of statistical significance. It may be that the cognitive processes that normally guide eye movements during reading exert less control during mind wandering episodes. Other implications and limitations are discussed.

Introduction: Metabolic syndrome (MetS) is a risk condition describing a clustering of traditional cardiovascular risk factors. A number of risk and protective factors have been associated with MetS, and individuals with MetS are at a higher risk for developing chronic diseases such as diabetes, cancer, and cardiovascular disease. Objective: To contribute to the understanding of MetS in Canada, and to describe how it is a risk state through which material, psychosocial, and behavioural factors associate with chronic diseases. This was examined through three objectives: (i) to describe the prevalence and distribution of MetS; (ii) to examine potential pathways linking income and education with MetS; and (iii) to examine the interplay between non-movement behaviours (NMBs, namely sleep, screen time, and sedentary behaviour) and MetS. Methods: The Canadian Health Measures Survey (2007-2009, 2009-2011, ages 18 and older) was used for all analyses, which include logistic regression, multinomial regression, and calculation of standardized logit coefficients. Results: MetS was prevalent among approximately 20% of Canadian adults. It was significantly associated with chronic diseases, such as diabetes (11.2% vs. 3.4% among those with MetS vs. the general population). A social gradient in MetS was identified, and the behavioural risk factors of alcohol use, smoking, physical inactivity, and screen time were suggested to be partial mediators of this pathway. Findings demonstrated that not adhering to physical activity guidelines (150 minutes or more of moderate-to-vigorous physical activity per week) was associated with increased odds of MetS. A stepwise moderating effect of guideline adherence on screen time and sleep behaviours was demonstrated. Conclusion: MetS is prevalent in Canadian adults, and a high proportion of individuals with MetS have chronic conditions. Addressing the modifiable determinants of physical inactivity, excess screen time, alcohol consumption, and smoking may reduce the social gradient in MetS. Furthermore, adhering to physical activity guidelines may mitigate the associations of NMBs with MetS. The current thesis suggests that healthy behaviours are associated with lower risk for MetS, and therefore, possibly for future chronic disease.

High levels of sedentary behaviour (SB) and low levels of physical activity (PA) in primary school children are a health concern especially for the South Asians (SA) because of increased cardiovascular risk. The study investigated ethnic differences in movement behaviours among primary school children in three studies: 1) inclinometer and accelerometer measured movement behaviours in White British (WB) vs. SA 6-8-year-old children; 2) qualitative studies with children, parents and teachers explored barriers and facilitators to reducing SB; and, 3) accelerometer measured movement behaviours in children aged 8-11-years. The inclinometer outcomes were: total SB, SB from bouts >30 minutes and breaks in SB, while accelerometry considered: SB, light PA and moderate to-vigorous PA and counts per minute. 525 children, eight parents and six teachers participated. No ethnic differences were identified in inclinometer outcomes except for SB breaks. SA children had 25 fewer breaks compared to WB. Accelerometry identified higher SB for SA children vs. WB in study one but no ethnic differences in study three; a pattern for higher SB/lower PA for SA children vs. WB was consistent in studies. Reasons for engagement in SB included: knowledge and beliefs about SB, child characteristics, cultural norms, parenting, educational system and the built environment. A large proportion of movement behaviour interventions components were related to education and policy. Children’s levels of SB were similar to office workers regardless of ethnicity. Interventions to reduce SB need to consider SB breaks and PA, especially for SA children who were less active and more sedentary than WB.

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Masters of Science (Environmental Sciences). September 2015. / African elephants (Loxodonta africana) are still being poached and hunted and this could potentially affect their movement. As a keystone species, crucial to maintaining ecosystem function and therefore food webs, it is important to understand the effects hunting may have on their movements. This study was undertaken in the Associated Private Nature Reserves adjacent to the Kruger National Park, where elephants are hunted. I looked at changes in daily displacement distance and distance from hunting and natural mortality events to determine if elephants were affected by hunting events, up to what distance, and to determine whether elephants reacted in the same way to hunting and natural mortality events. I found that elephants are only affected by hunting events when within 1 km of the event, which is consistent with the literature. When considering natural mortality events, they actually diverted movements towards the event location, which is also consistent with literature. These results, however, are based on a very small sample size. In addition, the time of day of the events was not recorded by the wardens of the reserve, and this provided a further limitation for the data analysis and interpretation.

Knowledge about the configuration of an environment is used preferentially when navigating through an urban environment (Penn, 2003). However, it the locus of this effect is poorly understood. One possibility is that the local environment, such as the shape of an intersection, is sufficient to determine route choice in the context of the global configuration of an environment (Meilinger, Franz, & Bülthoff, in press; Meilinger, Knauff & Bülthoff, 2008). Two experiments were performed to investigate this hypothesis using two novel virtual environments, one with a simplistic configuration, and one with a more complicated configuration. In Experiment 1, peripheral vision was either available or constrained throughout a wayfinding task. A significant influence of global configuration information with minimal use of local configuration account was found. In Experiment 2, central vision was either limited to the local intersection or unconstrained. Again, a strong effect of configuration was found, with limited evidence for the use of local visual information. The results support a synergistic mechanism of wayfinding where the environmental configuration is used to inform existing knowledge about the environment.

Knowledge about the configuration of an environment is used preferentially when navigating through an urban environment (Penn, 2003). However, it the locus of this effect is poorly understood. One possibility is that the local environment, such as the shape of an intersection, is sufficient to determine route choice in the context of the global configuration of an environment (Meilinger, Franz, & Bülthoff, in press; Meilinger, Knauff & Bülthoff, 2008). Two experiments were performed to investigate this hypothesis using two novel virtual environments, one with a simplistic configuration, and one with a more complicated configuration. In Experiment 1, peripheral vision was either available or constrained throughout a wayfinding task. A significant influence of global configuration information with minimal use of local configuration account was found. In Experiment 2, central vision was either limited to the local intersection or unconstrained. Again, a strong effect of configuration was found, with limited evidence for the use of local visual information. The results support a synergistic mechanism of wayfinding where the environmental configuration is used to inform existing knowledge about the environment.

This research paper is discussing light, and brightness in particular, in terms of perception, taking Odenplan as a case study.Some links between light characteristics and behaviour patterns, such as lingering, have been made, raising the discussion about the qualities of the artificial lighting that would add to convivial urban spaces at nighttime, attempting at differentiating between how people think they would behave and how they actually behave in a public square, and the impact of artificial lighting on public tendencies, suggesting if people feel comfortable and safe in the space, then they tend to perceive the space brighter. The research has shown that it is hard to draw conclusions when it comes to perceived qualities of light. Different research methods have been used with the intention of suggesting a methodology to be explored by others, including literature review, empirical study, informal interviews and word association survey.