Midlife managerial experience is linked to late life hippocampal morphology and function

An active cognitive lifestyle has been suggested to have a protective role in the long-term maintenance of cognition. Amongst healthy older adults, more managerial or supervisory experiences in midlife are linked to a slower hippocampal atrophy rate in late life. Yet whether similar links exist in individuals with Mild Cognitive Impairment (MCI) is not known, nor whether these differences have any functional implications. 68 volunteers from the Sydney SMART Trial, diagnosed with non-amnestic MCI, were divided into high and low managerial experience (HME/LME) during their working life. All participants underwent neuropsychological testing, structural and resting-state functional MRI. Group comparisons were performed on hippocampal volume, morphology, hippocampal seed-based functional connectivity, memory and executive function and self-ratings of memory proficiency. HME was linked to better memory function (p = 0.024), mediated by larger hippocampal volume (p = 0.025). More specifically, deformation analysis found HME had relatively more volume in the CA1 sub-region of the hippocampus (p  <  0.05). Paradoxically, this group rated their memory proficiency worse (p = 0.004), a result correlated with diminished functional connectivity between the right hippocampus and right prefrontal cortex (p  <  0.001). Finally, hierarchical regression modelling substantiated this double dissociation

Dissociable Effects of Reward on Attentional Learning: From Passive Associations to Active Monitoring

Visual selective attention (VSA) is the cognitive function that regulates ongoing processing of retinal input in order for selected representations to gain privileged access to perceptual awareness and guide behavior, facilitating analysis of currently relevant information while suppressing the less relevant input. Recent findings indicate that the deployment of VSA is shaped according to past outcomes. Targets whose selection has led to rewarding outcomes become relatively easier to select in the future, and distracters that have been ignored with higher gains are more easily discarded. Although outcomes (monetary rewards) were completely predetermined in our prior studies, participants were told that higher rewards would follow more efficient responses. In a new experiment we have eliminated the illusory link between performance and outcomes by informing subjects that rewards were randomly assigned. This trivial yet crucial manipulation led to strikingly different results. Items that were associated more frequently with higher gains became more difficult to ignore, regardless of the role (target or distracter) they played when differential rewards were delivered. Therefore, VSA is shaped by two distinct reward-related learning mechanisms: one requiring active monitoring of performance and outcome, and a second one detecting the sheer association between objects in the environment (whether attended or ignored) and the more-or-less rewarding events that accompany them

A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass

Background: The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance sac- charification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractiona- tion into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas organosolv is excellent for delignification but offers poor biomass deconstruction. Results: In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pre - treatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) were evaluated. Pretreatment of birch at 200 °C with 60% v/v ethanol and 1% w/w biomass H 2 SO 4 was proven to be the most efficient pretreatment condition yielding pretreated solids with 77.9% w/w cellulose, 8.9% w/w hemicellulose, and 7.0 w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25% w/w, respectively, and ash to be < 0.17% w/w in all cases, making it suitable for various applications. The pretreated solids presented high saccharification yields, reaching 68% at low enzyme load (6 FPU/g) and complete saccharification at high enzyme load (22.5 FPU/g). Finally, simultaneous saccharification and fermentation (SSF) at 20% w/w solids yielded an ethanol titer of 80 g/L after 192 h, corresponding to 90% of the theoretical maximum. Conclusions: The novel hybrid method developed in this study allowed for the efficient fractionation of birch biomass and production of pretreated solids with high cellulose and low lignin contents. Moreover, the explosive dis- charge at the end of pretreatment had a positive effect on enzymatic saccharification, resulting in high hydrolyzability of the pretreated solids and elevated ethanol titers in the following high-gravity SSF. To the best of our knowledge, the ethanol concentration obtained with this method is the highest so far for birch biomass

The representation of Kanizsa illusory contours in the monkey inferior temporal cortex

Stimulus reduction is an effective way to study visual performance. Cues such as surface characteristics, colour and inner lines can be removed from stimuli, revealing how the change affects recognition and neural processing. An extreme reduction is the removal of the very stimulus, defining it with illusory lines. Perceived boundaries without physical differences between shape and background are called illusory (or subjective) contours. Illusory and real contours activate early stages of the macaque visual pathway in similar ways. However, data relating to the processing of illusory contours in higher visual areas are scarce. We recently reported how illusory contours based on abutting-line gratings affect neurones in the monkey inferotemporal cortex, an area essential for object and shape vision. We now present data on how inferotemporal cortical neurones of monkeys react to another type of shapes, the Kanizsa figures. A set of line drawings, silhouettes, their illusory contour-based counterparts, and control shapes have been presented to awake, fixating rhesus monkeys while single-cell activity was recorded in the anterior part of the inferotemporal cortex. Most of the recorded neurones were responsive and selective to shapes presented as illusory contours. Shape selectivity was proved to be different for line drawings and illusory contours, and also for silhouettes and illusory contours. Neuronal response latencies for Kanizsa figures were significantly longer than those for line drawings and silhouettes. These results reveal differences in processing for Kanizsa figures and shapes having real contours in the monkey inferotemporal cortex