No abstract

How the human brain generates conscious phenomenal experience is a fundamental problem. In particular, it is unknown how variable and dynamic changes in subjective affect are driven by interactions with objective phenomena. We hypothesize a neurocomputational mechanism that generates valence-specific learning signals associated with 'what it is like' to be rewarded or punished. Our hypothesized model maintains a partition between appetitive and aversive information while generating independent and parallel reward and punishment learning signals. This valence-partitioned reinforcement learning (VPRL) model and its associated learning signals are shown to predict dynamic changes in 1) human choice behavior, 2) phenomenal subjective experience, and 3) BOLD-imaging responses that implicate a network of regions that process appetitive and aversive information that converge on the ventral striatum and ventromedial prefrontal cortex during moments of introspection. Our results demonstrate the utility of valence-partitioned reinforcement learning as a neurocomputational basis for investigating mechanisms that may drive conscious experience.

This article considers a range of responses to Plato's Symposium, paying particular attention to Diotima's speech on eros and philosophy. It argues that Diotima's teachings contain resources for a relational pedagogy, but that these resources come more sharply into focus when Plato's text is read through the lens of contemporary (20th and 21st century) thinkers. The article therefore draws on the work of David Halperin, Hannah Arendt, Jean‐François Lyotard and Luce Irigaray to argue that Diotima points us towards the value of educative encounters as reciprocal and unpredictable events of initiation and becoming. Diotima's rhetorical emphasis on birth is shown to be especially important for refiguring pedagogical relations in terms of natality, understood as a capacity for new beginnings, and hence for reclaiming education as a potentially generative encounter, rather than one governed by the logic of reproduction. The final section of the article turns to work by Christine Battersby, bell hooks, Richard Smith and Morwenna Griffiths to resituate the discussion in relation to questions of autonomy. As a corrective to the modern bias towards the value of the autonomous individual, it argues that dependencies and unequal power relations can be a constitutive and enabling aspect of the educative process. Attention to such relations should thus form a key part of a relational pedagogy.

Dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. Decreasing striatal dopamine efficacy is at the core of Parkinson’s disease (PD) motor symptoms and changes in dopaminergic action have been associated with many comorbid non-motor symptoms in PD. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. We recruited patients with PD and compared individual differences in patients’ clinical features with their ability to judge millisecond to second intervals of time (500ms-1100ms) while on or off their prescribed dopaminergic medications. We show that individual differences in comorbid non-motor symptoms, PD duration, and prescribed dopaminergic pharmacotherapeutics account for individual differences in time perception performance. We report that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and PD disease duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD, but also raise questions about specific dopaminergic mechanisms. In future work, time perception tasks like the one used here, may provide translational or reverse translational utility in investigations aimed at disentangling neural and cognitive systems underlying PD symptom etiology.One Sentence SummaryQuantitative characterization of time perception behavior reflects individual differences in Parkinson’s disease motor and non-motor symptom clinical presentation that are consistent with hypothesized neural and cognitive mechanisms.