Comparison of Muscle Activation During an Overhead Pres: Kettlebell v. Dumbbell

Please refer to the pdf version of the abstract located adjacent to the title

Double Dissociation of Amygdala and Hippocampal Contributions to Trace and Delay Fear Conditioning

A key finding in studies of the neurobiology of learning memory is that the amygdala is critically involved in Pavlovian fear conditioning. This is well established in delay-cued and contextual fear conditioning; however, surprisingly little is known of the role of the amygdala in trace conditioning. Trace fear conditioning, in which the CS and US are separated in time by a trace interval, requires the hippocampus and prefrontal cortex. It is possible that recruitment of cortical structures by trace conditioning alters the role of the amygdala compared to delay fear conditioning, where the CS and US overlap. To investigate this, we inactivated the amygdala of male C57BL/6 mice with GABA A agonist muscimol prior to 2-pairing trace or delay fear conditioning. Amygdala inactivation produced deficits in contextual and delay conditioning, but had no effect on trace conditioning. As controls, we demonstrate that dorsal hippocampal inactivation produced deficits in trace and contextual, but not delay fear conditioning. Further, pre- and post-training amygdala inactivation disrupted the contextual but the not cued component of trace conditioning, as did muscimol infusion prior to 1- or 4-pairing trace conditioning. These findings demonstrate that insertion of a temporal gap between the CS and US can generate amygdala-independent fear conditioning. We discuss the implications of this surprising finding for current models of the neural circuitry involved in fear conditioning

Blue Light at Night and Corticosterone: Disrupting Rodent Learning and Memory

Light pollution is a major issue, contributing to disruptions in human circadian rhythms, including sleep cycle, metabolism, and hormone synthesis and release. This pollution comes from streetlights and sporting stadiums, as well as other contributors such as smart phones, tablets and computers. These smart devices emit blue light, which has been found to have more detrimental effects on circadian rhythms than white light. Light at night has been associated with decreased learning and memory and an increase in cortisol, the stress hormone. The aim of this study was to examine the effect of blue light at night on rodent learning and memory in the water radial arm maze. Trilostane, used to block corticosterone synthesis, was administered daily to male SAS rats in 8mg/kg doses. Subjects were split into four groups, half in light at night and half in a normal 12-hour light dark cycle, and half of each group received trilostane. There appeared to be a trend reflective of learning across all groups for the twelve days in the WRAM. Additionally, there appears to be a difference in learning for the light condition groups, with the light at night condition appearing to learn more slowly than the light/dark condition. There was no significant difference in corticosterone levels for the drug conditions. However, it can be said that the presence of blue light at night does negatively impact learning and memory in the beginning stages of learning