title: Effect of oxytocin on hunger discrimination

authors: Head, Mitchell Antony

subjects: Science & Technology

abstract: Centrally and peripherally administered oxytocin (OT) decreases food intake and activation of the endogenous OT systems, which is associated with termination of feeding. Evidence gathered thus far points to OT as a facilitator of early satiation, a peptide that reduces the need for a meal that has already begun. It is not known, however, whether OT can diminish a feeling of hunger, thereby decreasing a perceived need to seek calories. Therefore, in the current project, we first confirmed that intraperitoneal (i.p.) OT at 0.3–1 mg/kg reduces food intake in deprived and non-deprived rats. We then used those OT doses in a unique hunger discrimination protocol. First, rats were trained to discriminate between 22- and 2-h food deprivation (hungry vs. sated state) in a two-lever operant procedure. After rats acquired the discrimination, they were food-restricted for 22 h and given i.p. OT before a generalization test session. OT did not decrease 22-h deprivation-appropriate responding to match that following 2-h food deprivation, thus, it did not reduce the perceived level of hunger. In order to better understand the mechanisms behind this ineffectiveness of OT, we used c-Fos immunohistochemistry to determine whether i.p. OT activates a different subset of feeding-related brain sites under 22- vs. 2-h deprivation. We found that in sated animals, OT induces c-Fos changes in a broader network of hypothalamic and brain stem sites compared to those affected in the hungry state. Finally, by employing qPCR analysis, we asked whether food deprivation vs. sated state have an impact on OT receptor expression in the brain stem, a CNS “entry” region for peripheral OT. Fasted animals had significantly lower OT receptor mRNA levels than their ad libitum-fed counterparts. We conclude that OT does not diminish a feeling of hunger before a start of a meal. Instead OT's anorexigenic properties are manifested once consumption has already begun which is—at least to some extent—driven by changes in brain responsiveness to OT treatment in the hungry vs. fed state. OT should be viewed as a mediator of early satiation rather than as a molecule that diminishes perceived hunger.

text: Effect of oxytocin on hunger discrimination Centrally and peripherally administered oxytocin (OT) decreases food intake and activation of the endogenous OT systems, which is associated with termination of feeding. Evidence gathered thus far points to OT as a facilitator of early satiation, a peptide that reduces the need for a meal that has already begun. It is not known, however, whether OT can diminish a feeling of hunger, thereby decreasing a perceived need to seek calories. Therefore, in the current project, we first confirmed that intraperitoneal (i.p.) OT at 0.3–1 mg/kg reduces food intake in deprived and non-deprived rats. We then used those OT doses in a unique hunger discrimination protocol. First, rats were trained to discriminate between 22- and 2-h food deprivation (hungry vs. sated state) in a two-lever operant procedure. After rats acquired the discrimination, they were food-restricted for 22 h and given i.p. OT before a generalization test session. OT did not decrease 22-h deprivation-appropriate responding to match that following 2-h food deprivation, thus, it did not reduce the perceived level of hunger. In order to better understand the mechanisms behind this ineffectiveness of OT, we used c-Fos immunohistochemistry to determine whether i.p. OT activates a different subset of feeding-related brain sites under 22- vs. 2-h deprivation. We found that in sated animals, OT induces c-Fos changes in a broader network of hypothalamic and brain stem sites compared to those affected in the hungry state. Finally, by employing qPCR analysis, we asked whether food deprivation vs. sated state have an impact on OT receptor expression in the brain stem, a CNS “entry” region for peripheral OT. Fasted animals had significantly lower OT receptor mRNA levels than their ad libitum-fed counterparts. We conclude that OT does not diminish a feeling of hunger before a start of a meal. Instead OT's anorexigenic properties are manifested once consumption has already begun which is—at least to some extent—driven by changes in brain responsiveness to OT treatment in the hungry vs. fed state. OT should be viewed as a mediator of early satiation rather than as a molecule that diminishes perceived hunger.

year: 2019

title: An appreciative view of year 9 student leadership in a New Zealand secondary school context

authors: Mackay, Janine Karen

subjects: Student Leadership

abstract: Engaging students in relevant and meaningful leadership activities in schools can prove to be a challenging task. Understanding the leadership experiences and skills that students have is an important beginning step to understanding how schools can best serve their needs. This thesis shares the details of a qualitative research project, which explored year 9 students’ perspectives and experiences of leadership. The study engaged a strengths-based approach to learning and, amongst other things, encouraged students to reflect upon past experiences of leadership. Central to the research design were the voices of the students as they examined these past experiences to find out what factors made leadership enjoyable, meaningful and useful to them. 
The findings indicated the significant difference in opportunities students were provided in year 8 (intermediate school) as compared with year 9 (secondary school). Coming from environments where students most often had significant leadership opportunities, upon entering high school students perceived few opportunities for leadership. Students shared their views about ways they could contribute to and be involved in leadership at secondary school and suggested changes that needed to occur for this to happen. The findings also highlighted the powerful influence of the school and family on students’ leadership understandings and demonstrated that leadership development for young people should not be something schools ‘do’ to them but something that encourages them to recognise their existing skills and future potential.

text: An appreciative view of year 9 student leadership in a New Zealand secondary school context Engaging students in relevant and meaningful leadership activities in schools can prove to be a challenging task. Understanding the leadership experiences and skills that students have is an important beginning step to understanding how schools can best serve their needs. This thesis shares the details of a qualitative research project, which explored year 9 students’ perspectives and experiences of leadership. The study engaged a strengths-based approach to learning and, amongst other things, encouraged students to reflect upon past experiences of leadership. Central to the research design were the voices of the students as they examined these past experiences to find out what factors made leadership enjoyable, meaningful and useful to them. 
The findings indicated the significant difference in opportunities students were provided in year 8 (intermediate school) as compared with year 9 (secondary school). Coming from environments where students most often had significant leadership opportunities, upon entering high school students perceived few opportunities for leadership. Students shared their views about ways they could contribute to and be involved in leadership at secondary school and suggested changes that needed to occur for this to happen. The findings also highlighted the powerful influence of the school and family on students’ leadership understandings and demonstrated that leadership development for young people should not be something schools ‘do’ to them but something that encourages them to recognise their existing skills and future potential.

year: 2014

title: Who owns native nature? Discourses of rights to land, culture, and knowledge in New Zealand

authors: Goldsmith, Michael

subjects: indigenous cultures

abstract: Michael Brown famously asked ‘Who owns native culture?’ This paper revisits that question by analyzing what happens to culture when the culturally defined boundary between it and nature becomes salient in the context of disputes between indigenous and settler populations. My case study is the dispute between the New Zealand government and Maori tribal groupings concerning ownership of the foreshore and seabed. Having been granted the right to test their claims in court in 2003, Maori groups were enraged when the government legislated the right out of existence in 2004. Though the reasons for doing so were clearly political, contrasting cultural assumptions appeared to set Maori and Pakeha (New Zealanders of European origin) at odds. While couching ownership of part of nature as an IPR issue may seem counter-intuitive, I argue that as soon as a property claim destabilizes the nature/culture boundary, IPR discourse becomes pertinent.

text: Who owns native nature? Discourses of rights to land, culture, and knowledge in New Zealand Michael Brown famously asked ‘Who owns native culture?’ This paper revisits that question by analyzing what happens to culture when the culturally defined boundary between it and nature becomes salient in the context of disputes between indigenous and settler populations. My case study is the dispute between the New Zealand government and Maori tribal groupings concerning ownership of the foreshore and seabed. Having been granted the right to test their claims in court in 2003, Maori groups were enraged when the government legislated the right out of existence in 2004. Though the reasons for doing so were clearly political, contrasting cultural assumptions appeared to set Maori and Pakeha (New Zealanders of European origin) at odds. While couching ownership of part of nature as an IPR issue may seem counter-intuitive, I argue that as soon as a property claim destabilizes the nature/culture boundary, IPR discourse becomes pertinent.

year: 2009