The pion nucleon sigma term

This thesis calculates and compares the pion nucleon sigma term with and without the contributions arising from processes that involve decuplet baryons.Thesis (M.Sc.) -- University of Adelaide, Dept. of Physics and Mathematical Physics, 1996

Structural learning and the hippocampus

It is argued that while the hippocampus is not vital for all classes of configural learning, it is vital for a specific subclass of configural tasks called “structural learning.” The defining feature of structural learning is that in addition to binding stimulus elements to make unique arrays (as in all configural learning), the relationship of these elements to each other, be it spatial or temporal, is specified. Direct evidence supporting the proposal that the hippocampus is required for structural learning comes from recent lesion studies with rats. While rats with hippocampal lesions were impaired at relearning a set of spatial structural problems, they showed no impairment when relearning two configural tasks (transverse patterning and the biconditional discrimination), neither of which required structural learning. Other support comes from surveys of spatial and temporal learning by amnesic patients with hippocampal damage, and from imaging studies of both humans and rats. While these studies offer consistent support for the structural hypothesis, very few provide a rigorous test as the tasks can often be solved by other strategies. For this reason, the present review details the design features of future stringent tests of the structural hypothesis

Touchscreen cognitive testing: Cross-species translation and co-clinical trials in neurodegenerative and neuropsychiatric disease

Translating results from pre-clinical animal studies to successful human clinical trials in neurodegenerative and neuropsychiatric disease presents a significant challenge. While this issue is clearly multifaceted, the lack of reproducibility and poor translational validity of many paradigms used to assess cognition in animal models are central contributors to this challenge. Computer-automated cognitive test batteries have the potential to substantially improve translation between pre-clinical studies and clinical trials by increasing both reproducibility and translational validity. Given the structured nature of data output, computer-automated tests also lend themselves to increased data sharing and other open science good practices. Over the past two decades, computer automated, touchscreen-based cognitive testing methods have been developed for non-human primate and rodent models. These automated methods lend themselves to increased standardization, hence reproducibility, and have become increasingly important for the elucidation of the neurobiological basis of cognition in animal models. More recently, there have been increased efforts to use these methods to enhance translational validity by developing task batteries that are nearly identical across different species via forward (i.e., translating animal tasks to humans) and reverse (i.e., translating human tasks to animals) translation. An additional benefit of the touchscreen approach is that a cross-species cognitive test battery makes it possible to implement co-clinical trials—an approach developed initially in cancer research—for novel treatments for neurodegenerative disorders. Co-clinical trials bring together pre-clinical and early clinical studies, which facilitates testing of novel treatments in mouse models with underlying genetic or other changes, and can help to stratify patients on the basis of genetic, molecular, or cognitive criteria. This approach can help to determine which patients should be enrolled in specific clinical trials and can facilitate repositioning and/or repurposing of previously approved drugs. This has the potential to mitigate the resources required to study treatment responses in large numbers of human patients