title: The sleep cycle modelled as a cortical phase transition

authors: Steyn-Ross, D. Alistair

subjects: cortical model

abstract: We present a mean-field model of the cortex that attempts to describe the gross changes in brain electrical activity for the cycles of natural sleep. We incorporate within the model two major sleep modulatory effects: slow changes in both synaptic efficiency and in neuron resting voltage caused by the ∼90-min cycling in acetylcholine, together with even slower changes in resting voltage caused by gradual elimination during sleep of somnogens (fatigue agents) such as adenosine. We argue that the change from slow-wave sleep (SWS) to rapid-eye-movement (REM) sleep can be understood as a first-order phase transition from a low-firing, coherent state to a high-firing, desychronized cortical state. We show that the model predictions for changes in EEG power, spectral distribution, and correlation time at the SWS-to-REM transition are consistent not only with those observed in clinical recordings of a sleeping human subject, but also with the on-cortex EEG patterns recently reported by Destexhe et al. [J. Neurosci. 19(11), (1999) 4595–4608] for the sleeping cat.

text: The sleep cycle modelled as a cortical phase transition We present a mean-field model of the cortex that attempts to describe the gross changes in brain electrical activity for the cycles of natural sleep. We incorporate within the model two major sleep modulatory effects: slow changes in both synaptic efficiency and in neuron resting voltage caused by the ∼90-min cycling in acetylcholine, together with even slower changes in resting voltage caused by gradual elimination during sleep of somnogens (fatigue agents) such as adenosine. We argue that the change from slow-wave sleep (SWS) to rapid-eye-movement (REM) sleep can be understood as a first-order phase transition from a low-firing, coherent state to a high-firing, desychronized cortical state. We show that the model predictions for changes in EEG power, spectral distribution, and correlation time at the SWS-to-REM transition are consistent not only with those observed in clinical recordings of a sleeping human subject, but also with the on-cortex EEG patterns recently reported by Destexhe et al. [J. Neurosci. 19(11), (1999) 4595–4608] for the sleeping cat.

year: 2005-12

title: Taste predicates and retraction data: An improved framework

authors: Wyatt, Jeremy

abstract: Predicates of personal taste (PPT), which include words like ‘tasty,’ ‘fun,’ and ‘cool,’ have been at the centre of a set of lively, interdisciplinary debates spanning the past 20 years. Over this period, philosophers and linguists have developed five major accounts of what PPT mean and the sort of truth (if any) for which assertions involving PPT are apt. In this talk, I will explore one of the main empirical diagnostics that should be used in evaluating the ‘big five’ analyses of PPT, which involves considerations about retraction. After setting out the ‘big five’ analyses, I'll review the most influential account of why retraction data matter in the PPT debates, which comes from John MacFarlane. I take MacFarlane’s account to suffer from two significant problems, and after identifying them, I’ll develop an improved framework for thinking about retraction data and PPT. I'll then draw on this improved framework in reframing the significance of our current empirical data.

text: Taste predicates and retraction data: An improved framework Predicates of personal taste (PPT), which include words like ‘tasty,’ ‘fun,’ and ‘cool,’ have been at the centre of a set of lively, interdisciplinary debates spanning the past 20 years. Over this period, philosophers and linguists have developed five major accounts of what PPT mean and the sort of truth (if any) for which assertions involving PPT are apt. In this talk, I will explore one of the main empirical diagnostics that should be used in evaluating the ‘big five’ analyses of PPT, which involves considerations about retraction. After setting out the ‘big five’ analyses, I'll review the most influential account of why retraction data matter in the PPT debates, which comes from John MacFarlane. I take MacFarlane’s account to suffer from two significant problems, and after identifying them, I’ll develop an improved framework for thinking about retraction data and PPT. I'll then draw on this improved framework in reframing the significance of our current empirical data.

year: 2022

title: Relational and culturally responsive supervision of doctoral students working in Māori contexts: Inspirations from the Kingitanga

authors: Glynn, Ted

subjects: Relational and culturally responsive supervision

abstract: There is much to celebrate in the greatly increased number of Māori and non-Māori students in New Zealand tertiary institutions undertaking doctoral research on issues of importance to Māori.
However, in honouring their commitments to the Treaty of Waitangi, tertiary institutions need to ensure that Māori doctoral students and their Māori communities maintain their right to define their own research questions, research paradigms and methodologies. As supervisors of doctoral research students investigating issues of significance to Māori people, it is essential that we learn to position ourselves as visitors in someone else’s cultural space, as partners in the Treaty of Waitangi, and as co-constructors of knowledge and research methodology rather than as experts and gatekeepers (Berryman, SooHoo, & Nevin, 2013; Glynn, 2012).

This paper was occasioned by an invitation from the organisers of the annual Kingitanga Day cultural and educational programme at the University of Waikato. The Kingitanga movement has much to teach us about how to frame and conduct research that responds to long-standing injustices that have marginalised Māori people. The Kingitanga has inspired us through the resistance, resilience, agency and humility of its leaders in asserting their right to define the effects of historic and contemporary injustices, and the right to define their own responses to these injustices.

In this paper, we explore some of the relational and culturally responsive understandings we have arrived at from supervising the research of four doctoral candidates in Education (two Māori and two non-Māori). This research has been designed to promote the success and wellbeing of Māori students in mainstream schools, addressing historic and ongoing injustices experienced by Māori students and their whānau and communities.

text: Relational and culturally responsive supervision of doctoral students working in Māori contexts: Inspirations from the Kingitanga There is much to celebrate in the greatly increased number of Māori and non-Māori students in New Zealand tertiary institutions undertaking doctoral research on issues of importance to Māori.
However, in honouring their commitments to the Treaty of Waitangi, tertiary institutions need to ensure that Māori doctoral students and their Māori communities maintain their right to define their own research questions, research paradigms and methodologies. As supervisors of doctoral research students investigating issues of significance to Māori people, it is essential that we learn to position ourselves as visitors in someone else’s cultural space, as partners in the Treaty of Waitangi, and as co-constructors of knowledge and research methodology rather than as experts and gatekeepers (Berryman, SooHoo, & Nevin, 2013; Glynn, 2012).

This paper was occasioned by an invitation from the organisers of the annual Kingitanga Day cultural and educational programme at the University of Waikato. The Kingitanga movement has much to teach us about how to frame and conduct research that responds to long-standing injustices that have marginalised Māori people. The Kingitanga has inspired us through the resistance, resilience, agency and humility of its leaders in asserting their right to define the effects of historic and contemporary injustices, and the right to define their own responses to these injustices.

In this paper, we explore some of the relational and culturally responsive understandings we have arrived at from supervising the research of four doctoral candidates in Education (two Māori and two non-Māori). This research has been designed to promote the success and wellbeing of Māori students in mainstream schools, addressing historic and ongoing injustices experienced by Māori students and their whānau and communities.

year: 2015