Level of uncertainty about the affective nature of a pictorial stimulus influences anticipatory neural processes: An event-related potential (ERP) study.

Uncertainty about the emotional impact of future events is a common part of everyday life. However, relatively little is known about whether the level of uncertainty about the affective nature of an upcoming visual image influences anticipatory neurocognitive processes. To investigate this, participants viewed a series of negative and neutral pictures, which were preceded by abstract anticipatory cues. Neural activity was measured using event-related potentials (ERPs). In the 'uncertain' cue condition, the cue could be followed by either a negative or a neutral picture with equal probability; in the 'fairly uncertain' condition the cue was followed by a negative picture on 70% of trials, and by a neutral picture on 30% of trials. In the 'certain' condition, the cue was always followed by a negative picture. For the P200 component, reflecting early stages of selective attention, there was no amplitude difference between cue conditions. At later stages of processing, the early posterior negativity (EPN) amplitude was enhanced for cues indicating a greater level of certainty, and the late positive potential (LPP) amplitude was greater for certain, compared to fairly uncertain and uncertain cues. The stimulus preceding negativity (SPN), an index of anticipatory processing, was more negative for certain cues compared to fairly uncertain and uncertain cues. For the SPN there was no difference between fairly uncertain and uncertain cues. These results provide evidence that the level of uncertainty regarding the affective nature of an upcoming picture influenced several stages of processing during the anticipation of the stimulus.

Visual attention, EEG alpha power and T7-Fz connectivity are implicated in prosthetic hand control and can be optimized through gaze training.

BACKGROUND: Prosthetic hands impose a high cognitive burden on the user that often results in fatigue, frustration and prosthesis rejection. However, efforts to directly measure this burden are sparse and little is known about the mechanisms behind it. There is also a lack of evidence-based training interventions designed to improve prosthesis hand control and reduce the mental effort required to use them. In two experiments, we provide the first direct evaluation of this cognitive burden using measurements of EEG and eye-tracking (Experiment 1), and then explore how a novel visuomotor intervention (gaze training; GT) might alleviate it (Experiment 2). METHODS: In Experiment 1, able-bodied participants (n = 20) lifted and moved a jar, first using their anatomical hand and then using a myoelectric prosthetic hand simulator. In experiment 2, a GT group (n = 12) and a movement training (MT) group (n = 12) trained with the prosthetic hand simulator over three one hour sessions in a picking up coins task, before returning for retention, delayed retention and transfer tests. The GT group received instruction regarding how to use their eyes effectively, while the MT group received movement-related instruction typical in rehabilitation. RESULTS: Experiment 1 revealed that when using the prosthetic hand, participants performed worse, exhibited spatial and temporal disruptions to visual attention, and exhibited a global decrease in EEG alpha power (8-12 Hz), suggesting increased cognitive effort. Experiment 2 showed that GT was the more effective method for expediting prosthesis learning, optimising visual attention, and lowering conscious control - as indexed by reduced T7-Fz connectivity. Whilst the MT group improved performance, they did not reduce hand-focused visual attention and showed increased conscious movement control. The superior benefits of GT transferred to a more complex tea-making task. CONCLUSIONS: These experiments quantify the visual and cortical mechanisms relating to the cognitive burden experienced during prosthetic hand control. They also evidence the efficacy of a GT intervention that alleviated this burden and promoted better learning and transfer, compared to typical rehabilitation instructions. These findings have theoretical and practical implications for prosthesis rehabilitation, the development of emerging prosthesis technologies and for the general understanding of human-tool interactions.

Brief Exposure to Pictures Depicting Poor Environments Leads to Increased Consumption of Beer in Adult Social Drinkers.

Previous studies have suggested a trait-like association between neighborhood deprivation and alcohol consumption. However, it is not known whether temporarily manipulating poverty and affluence states by exposure to stimuli signifying resource-scarcity or resource-wealth would influence alcohol-seeking behavior. Here, we aimed to investigate whether implicit exposure to affluence and poverty-related pictures would influence beer consumption. Participants in a "poverty" group viewed pictures depicting impoverished environments, and participants in an "affluence" group viewed images of wealthy environments. After priming, participants were provided with nonalcoholic beer (which they were told was alcohol-containing beer) and orange juice under the guise of a bogus taste test, to measure their alcohol-seeking behavior. Results showed that priming participants with a resource-scarce environment led to an increase in beer consumption (as a percentage of total fluid consumed), compared to priming with a resource-rich environment. The same pattern of results was obtained in both a Western European sample (Experiment 1) and a West Indian sample (Experiment 2). In Experiment 2, we also tested whether risk-taking behavior, measured by the Balloon Analogue Risk Task, was influenced by the environmental priming; no differences between groups were observed. These results provide the first experimental evidence that manipulation of poverty-affluence state, by brief exposure to pictures of impoverished or wealthy neighborhoods, can influence alcohol-seeking behavior in adult social drinkers.

Examining the Spatiotemporal Disruption to Gaze When Using a Myoelectric Prosthetic Hand.

The aim of this study was to provide a detailed account of the spatial and temporal disruptions to eye-hand coordination when using a prosthetic hand during a sequential fine motor skill. Twenty-one able-bodied participants performed 15 trials of the picking up coins task derived from the Southampton Hand Assessment Procedure with their anatomic hand and with a prosthesis simulator while wearing eye-tracking equipment. Gaze behavior results revealed that when using the prosthesis, performance detriments were accompanied by significantly greater hand-focused gaze and a significantly longer time to disengage gaze from manipulations to plan upcoming movements. The study findings highlight key metrics that distinguish disruptions to eye-hand coordination that may have implications for the training of prosthesis use.