Disambiguating the Similar: Investigating Pattern Separation in Medial Temporal Lobe Structures Using Rodent Models

This dissertation investigates the mechanisms underlying pattern separation, using rodent models and behavioural tasks that assess the use of representations for similar stimuli. Pattern separation is a theoretical mechanism involving the transformation of inputs into output representations that are less correlated to each other. Because of this orthogonalizing process, similar experiences are stored as discrete non-overlapping representations. Studying pattern separation emphasizes the important but often overlooked fact that successful memory involves more than just remembering events over a period of time, but also differentiating between similar memories. Through a series of experiments this dissertation adds support to the literature that the dentate gyrus (DG) subregion of the hippocampus is important for pattern separation when encoding spatial and contextual inputs. Using the Spontaneous Location Recognition (SLR) task it is shown the brain-derived neurotrophic factor (BDNF) can improve performance by acting via N-methyl-D-aspartate (NMDA) glutamate receptors in the DG and adult-born hippocampal neurons. Manipulating the level of neurogenesis by inhibiting Wnt signalling or by administering acyl-ghrelin systemically is shown to impair and enhance performance on SLR, respectively. Using a novel exposure paradigm in combination with SLR, it is demonstrated for the first time that the relationship between pattern separation and neurogenesis may be reciprocal, such that inhibiting neurogenesis impairs pattern separation, enhancing neurogenesis improves pattern separation, and performing pattern separation enhances the production or survival of adult-born hippocampal neurons. Finally, it is shown that the $TgTau^{P301L}$ mouse model of dementia exhibits spatial and object recognition memory impairments once aged, recapitulating a dementia-like phenotype. Understanding the mechanisms that contribute to effective pattern separation may help elucidate the processes underlying the memory impairment experienced by AD patients. This dissertation concludes with a critical discussion about whether pattern separation can be studied using behavioural paradigms.Gates Cambridge; NSERC; St. John’s Colleg

Weda pool cleaner Concept P100

Syftet med detta examensarbete var att ta fram en ny drivlina för Wedas nuvarande robot poolrengörare W50. I nuläget är pumpen integrerad i drivlinan som består endast av en motor som driver både hjul och pump. Detta orsakar ett kritiskt problem som påverkar städning vid lutningar i poolen då roboten glider ner för lutningen. För att få en bättre insikt i hur produkten fungerar gjordes studiebesök till Weda. Projektgruppendokumenterade och observerade hur den nuvarande modellen och dess komponenter är monterade. Intervjuer utfördes med vaktmästare och fastighetsskötare inom olika kommunala bad och hotellpooler för att få en djupare förståelse för hur dessa robot poolrengörare används och vilka förbättringsområden som finns. Faktainsamlingen användes som grund för att ta fram förslag för nya och alternativa komponenter till det nya konceptet. De olika lösningarna blev sedan utvärderade med hjälp en beslutsmatris för att kunna bestämma vilka komponenter som skulle ingå i det slutgiltiga konceptet. Arbetet har utförts i nära samarbete med Adigo Drives, som bistått med sin expertis gällande motorer och drivlinor. Resultatet utmynnade i ett slutgiltigt koncept med en ny drivlina och en lägre vikt än den befintliga roboten.The purpose of this study was to develop a new drivetrain for Wedas current robot pool cleaner W50. Currently, the pump is integrated in the drivetrain which contains only one motor running both wheels and pump. This causes a critical problem affecting cleaning when encountering inclinations in the pool, the robot slides down the slope. To get a better understanding of how the product works, the project group made study visits to Weda. The group documented and observed how the current model and its components are mounted. Interviews were conducted with caretakers and janitors at various municipal swimming pools and hotel pools to get a deeper understanding of how these robot pool cleaners are used and what areas for improvement that exists. The research was used as a foundation for suggestions of new and alternative components for the new concept. The different solutions were then evaluated using a decision matrix to determine which components should be included in the final concept. The work has been carried out in close cooperation with Adigo Drives, which assisted the group with their expertise regarding motors and powertrains. The results culminated in a final concept with a new powertrain and a lower weight than the existing robot