Soma-Axon Coupling Configurations That Enhance Neuronal Coincidence Detection

Coincidence detector neurons transmit timing information by responding preferentially to concurrent synaptic inputs. Principal cells of the medial superior olive (MSO) in the mammalian auditory brainstem are superb coincidence detectors. They encode sound source location with high temporal precision, distinguishing submillisecond timing differences among inputs. We investigate computationally how dynamic coupling between the input region (soma and dendrite) and the spike-generating output region (axon and axon initial segment) can enhance coincidence detection in MSO neurons. To do this, we formulate a two-compartment neuron model and characterize extensively coincidence detection sensitivity throughout a parameter space of coupling configurations. We focus on the interaction between coupling configuration and two currents that provide dynamic, voltage-gated, negative feedback in subthreshold voltage range: sodium current with rapid inactivation and low-threshold potassium current, IKLT. These currents reduce synaptic summation and can prevent spike generation unless inputs arrive with near simultaneity. We show that strong soma-to-axon coupling promotes the negative feedback effects of sodium inactivation and is, therefore, advantageous for coincidence detection. Furthermore, the feedforward combination of strong soma-to-axon coupling and weak axon-to-soma coupling enables spikes to be generated efficiently (few sodium channels needed) and with rapid recovery that enhances high-frequency coincidence detection. These observations detail the functional benefit of the strongly feedforward configuration that has been observed in physiological studies of MSO neurons. We find that IKLT further enhances coincidence detection sensitivity, but with effects that depend on coupling configuration. For instance, in models with weak soma-to-axon and weak axon-to-soma coupling, IKLT in the axon enhances coincidence detection more effectively than IKLT in the soma. By using a minimal model of soma-to-axon coupling, we connect structure, dynamics, and computation. Although we consider the particular case of MSO coincidence detectors, our method for creating and exploring a parameter space of two-compartment models can be applied to other neurons

Financing structural interventions: going beyond HIV-only value for money assessments.

OBJECTIVE: Structural interventions can reduce HIV vulnerability. However, HIV-specific budgeting, based on HIV-specific outcomes alone, could lead to the undervaluation of investments in such interventions and suboptimal resource allocation. We investigate this hypothesis by examining the consequences of alternative financing approaches. METHODS: We compare three approaches for deciding whether to finance a structural intervention to keep adolescent girls in school in Malawi. In the first, HIV and non-HIV budget holders participate in a cross-sectoral cost-benefit analysis and fund the intervention if the benefits outweigh the costs. In the second silo approach, each budget holder considers the cost-effectiveness of the intervention in terms of their own objectives and funds the intervention on the basis of their sector-specific thresholds of what is cost-effective or not. In the third cofinancing approach, budget holders use cost-effectiveness analysis to determine how much they would be willing to contribute towards the intervention, provided that other sectors are willing to pay for the remaining costs. In addition, we explore approaches for determining the HIV share in the cofinancing scenario. RESULTS: We find that efficient structural interventions may be less likely to be prioritized, financed and taken to scale where sectors evaluate their options in isolation. A cofinancing approach minimizes welfare loss and could be incorporated in a sector budgeting perspective. CONCLUSION: Structural interventions may be underimplemented and their cross-sectoral benefits foregone. Cofinancing provides an opportunity for multiple HIV, health and development objectives to be achieved simultaneously, but will require effective cross-sectoral coordination mechanisms for planning, implementation and financing

Climate Research Wageningen UR : Projects, researchers and expertise

Wageningen UR focuses not only on the global climate system but also on regional and local climate phenomena, taking both scientific and social aspects into account in an integral way. Wageningen UR wants to play an effective role in the transition to a world that is both climate neutral and climate proof. Our strength is using the limited space available in our delta, in a climate-proof manner, thus providing opportunities for among others agriculture, horticulture, aquaculture, recreation and living

The Instability of Values: Tradition, Autonomy and the Dynamics of Sociality in the Philippine Highlands

What can we learn about values and how they shape sociality by looking at a murder? In this article, I look closer at the different and conflicting values involved in the social events leading up to an accidental killing of an outside visitor to a village in the northern highlands of the Philippines. I examine how these values were inherently instable and how this instability contributed to the precarious unfolding of sociality that took place before, during and after the murder. I situate the murder within a dynamic sociality that includes both humans and spirits and which operates as a continuously shifting form of relational configurations. This sociality, I argue, is given shape, although not necessarily order, by context-specific heterogeneous actualisations of values, including tradition and autonomy. Against claims that values exist most forcefully and tangibly in social life when they are realised in full, I argue that events such as the murder case, show us that values shape sociality just as forcefully, if not more, when they are actualised in practice and then run up against other differently actualised values.publishedVersio

The Effect of Energy Drink Consumption on Brake Reaction Time

Objective: To investigate if brake reaction times improve for college aged students after consuming an energy drink (ED). Design: Cross-sectional. Setting: College Setting Participants: 103 college aged participants (1=35, 2=34, 3=34). Brake reaction time tested 30 minutes post consumption of ED drink containing either 150 mg of caffeine, 34 mg of caffeine, or 0 mg of caffeine (placebo). Completion of Rand SF-36 general health and the General Knowledge Questionnaire for Adults surveys. Results: All groups improved brake reaction time from pre-to post-test. When comparing brake reaction time between groups, no statistical differences occurred. Conclusions: The majority of college students consumed caffeinated EDs primarily to improve their focus. However, consuming these drinks did not influence brake reaction times during sudden stops or while anticipating a stop. Therefore, college aged students should avoid relying on these drinks for safety when operating a motor vehicle

Maneuvering Contested Space and Community An Ethnographic Study of the Underground Electronic Music Scene in Itaewon

This thesis examines the dynamics of the underground electronic music scene in Itaewon, Seoul, South Korea, within the framework of contested space. Building upon the theories of Henri Lefebvre, Anthony Cohen, and Sarah Thornton, this research explores the formation of communities, spatiality, and the impact of the COVID-19 pandemic on Itaewon’s cultural landscape. Drawing from Lefebvre's reflections on spatial contestation, the study investigates how physical and symbolic spaces in Itaewon shape the experiences and interactions within the underground music scene. It delves into the significance of venues such as clubs and bars as cultural hubs, where diverse groups come together to express themselves and forge communities. Informed by Cohen's theory of community, the research sheds light on the social bonds, shared practices, and sense of belonging that emerge within the underground electronic music scene. It explores the collaborative endeavors, mutual support, and navigation of the complexities of the urban environment and the covid pandemic through stories from interlocuters and ethnography. Thornton's work on club culture provides insights into the role of music and cultural practices in shaping the experiences of individuals within the Itaewon underground club scene. It examines the intersections between music, and identity, highlighting the ambiance and social dynamics of the underground electronic music community. Furthermore, the study delves into the impact of the COVID-19 pandemic on the underground music scene in Itaewon. It delves into the myriad challenges artists, organizers, and participants confront as they navigate the constraints imposed by restrictions, strive to sustain connections, explore the quest for safe spaces, and seek out alternative pathways for creative expression. By integrating these theoretical perspectives, this thesis provides a comprehensive understanding of the underground electronic music scene in Itaewon, emphasizing its significance within the LGBTQ+ community. It illuminates the transformative power of inclusive cultural spaces, the role of music in identity formation, and the resilience of communities in the face of adversity. The findings contribute to urban anthropology and our understanding of contested spaces, cultural expressions, and the ongoing evolution of underground scenes.MasteroppgaveSANT350MASV-SAN