Heavy cannabis use and attentional avoidance of anxiety-related stimuli

Objectives Cannabis is now the most widely used illicit substance in the world. Previous research demonstrates that cannabis use is associated with dysfunctional affect regulation and anxiety. Anxiety is characterised by attentional biases in the presence of emotional information. This novel study therefore examined the attentional bias of cannabis users when presented with anxiety-related stimuli. The aim was to establish whether cannabis users respond to anxiety-related stimuli differently to control participants. Methods A dot-probe paradigm was utilised using 40 undergraduate students. Trials contained anxiety-related stimuli and neutral control stimuli. Eye-tracking was used to measure attention for the stimuli. Results Results indicated that cannabis users demonstrated attentional-avoidance behaviour when presented with anxiety-related stimuli. Conclusions The findings suggest a difference in processing of emotional information in relation to neutral information between groups. It would appear that cannabis users avoid anxiety provoking stimuli. Such behaviour could potentially have motivational properties that could lead to exacerbating anxiety disorder-type behaviour

Oculomotor and inhibitory control in dyslexia

Previous research has suggested that people with dyslexia may have an impairment of inhibitory control. The oculomotor system is vulnerable to interference at various levels of the system, from high level cognitive control to peripheral neural pathways. Therefore, in this work we examined two forms of oculomotor inhibition and two forms of oculomotor interference at high and low levels of the control system. This study employed a prosaccade, antisaccade, and a recent distractor eye movement task (akin to a spatial negative priming) in order to explore high level cognitive control and the inhibition of a competing distractor. To explore low-level control we examined the frequency of microsaccades and post-saccade oscillations. The findings demonstrated that dyslexics have an impairment of volitional inhibitory control, reflected in the antisaccade task. In contrast, inhibitory control at the location of a competing distractor was equivalent in the dyslexic and non-dyslexic groups. There was no difference in the frequency of microsaccades between the two groups. However, the dyslexic group generated larger microsaccades prior to the target onset in the prosaccade and the antisaccade tasks.The groups did not differ in the frequency or in the morphology of the post-saccade oscillations. These findings reveal that the word reading and attentional difficulties of dyslexic readers cannot be attributed to an impairment in the inhibition of a visual distractor or interference from low-level oculomotor instability. We propose that the inhibitory impairment in dyslexia occurs at a higher cognitive level, perhaps in relation to the process of attentional disengagement

Determining typical smartphone usage:What data do we need?

Problematic smartphone use is an emerging issue in behavioural addiction research. At the same time, measuring smartphone use with mobile apps has become increasingly common. However, understanding how much data is necessary requires careful consideration if the field is to move forward. Here, we examine how much time should be spent measuring mobile phone operation in order to reliably infer general patterns of usage and repetitive checking behaviours. In a second analysis, we consider whether a self-report measure of problematic smartphone use is associated with real-time patterns of use. Results suggest that smartphone usage collected for a minimum of five days will reflect typical weekly usage (in hours), but habitual checking behaviours (uses lasting less than 15 seconds) can be reliably inferred within two days. These measurements did not reliably correlate with a self-reported measure. We conclude that patterns of smartphone use are repetitive and our results suggest that checking behaviour is a particularly consistent and efficient measure when quantifying typical and problematic smartphone usage

Label-checking strategies to adapt behaviour to design

Despite robust quality control procedures, labelling errors on fresh produce are estimated to cost the UK supermarket industry approximately £50million pounds per year in product recalls and wastage. Changing the format of the labels themselves is not a viable option. Instead, the challenge is to change or guide human operatives' behaviour so that label printing errors do not go undetected during quality control procedures. To this end, a simulated label checking task was presented to naïve participants to compare more systematic and strategic methods of label checking. Two conditions in which behaviour was computer-led were compared with a control condition in which checkers adopted their own idiosyncratic checking method. The data indicate that the two computer-led approaches resulted in improved levels of accuracy. Pushing label checkers towards a more systematic approach would appear to be effective in reducing undetected label errors, and could lead potentially to significant financial savings and reduced environmental wastage in the fresh produce industry

Substance usage intention does not affect attentional bias: implications from Ecstasy/MDMA users and alcohol drinkers

Background: An attentional bias towards substance-related stimuli has been demonstrated with alcohol drinkers and many other types of substance user. There is evidence to suggest that the strength of an attentional bias may vary as a result of context (or use intention), especially within Ecstasy/MDMA users. Objective: Our aim was to empirically investigate attentional biases by observing the affect that use intention plays in recreational MDMA users and compare the findings with that of alcohol users. Method: Regular alcohol drinkers were compared with MDMA users. Performance was assessed for each group separately using two versions of an eye-tracking attentional bias task with pairs of matched neutral, and alcohol or MDMA-related visual stimuli. Dwell time was recorded for alcohol or MDMA. Participants were tested twice, when intending and not intending to use MDMA or alcohol. Note, participants in the alcohol group did not complete any tasks which involved MDMA-related stimuli and vice versa. Results: Significant attentional biases were found with both MDMA and alcohol users for respective substance-related stimuli, but not control stimuli. Critically, use intention did not affect attentional biases. Attentional biases were demonstrated with both MDMA users and alcohol drinkers when usage was and was not intended. Conclusions: These findings demonstrate the robust nature of attentional biases i.e. once an attentional bias has developed, it is not readily affected by intention

Maternal and cohort effects modulate offspring responses to multiple stressors

Current concerns about climate change have led to intensive research attempting to understand how climate driven stressors affect the performance of organisms, in particular on offspring of many invertebrates and fish. Although stressors are likely to act on several stages of the life cycle, little is known about their action across life phases, for instance how multiple stressors experienced simultaneously in the maternal environment can modulate the responses to the same stressors operating in the offspring environment. Here, we study how performance of offspring of a marine invertebrate (shore crab Carcinus maenas) in response to two stressors (temperature and salinity) changes if the same stressors are experienced at the time of embryogenesis in cohorts of mothers brooding eggs at different seasons. On average, offspring responses were antagonistic: high temperature mitigated the negative effects of low salinity on survival. However, the magnitude of the response was modulated by the temperature and salinity conditions experienced by egg-carrying mothers. Performance also varied among cohorts, perhaps reflecting genetic variation, and/or maternal conditions prior to embryogenesis. This study contributes towards the understanding of how anthropogenic modification of the maternal environment drives offspring performance in brooders

Effect of aging on post-saccadic oscillations

Recent research have shown that the eye movement data measured by an eye tracker does not necessarily reflect the exact rotations of the eyeball. For example, post-saccadic eye movements may be more reflecting the relative movements between the pupil and the iris rather than the eyeball oscillations. Since, accurate measurement of eye movements is important in many studies, it is crucial to identify different factors that influence the dynamics of the eye movements measured by an eye tracker. It has been shown that deformation of the internal structure of the iris and size of the pupil directly affect the amplitude of the post-saccadic oscillations that are measured by video-based eye trackers that are pupil-based. In this paper, we look at the effect of aging on post-saccadic oscillations. We recorded eye movements from a group of 43 young and 22 older participants during an abstract and a more natural viewing task. The recording was conducted with a video-based eye tracker using the pupil center and corneal reflection. We anticipated that changes in the muscle strength as an effect of aging might affect, directly or indirectly, the post-saccadic oscillations. Results showed that the size of the post-saccadic oscillations were significantly larger for our older group. The results suggests that aging has to be considered as an important factor when studying the post-saccadic eye movements

A comparison of post-saccadic oscillations in European-Born and China-Born British University Undergraduates

Previous research has revealed that people from different genetic, racial, biological, and/or cultural backgrounds may display fundamental differences in eye-tracking behavior. These differences may have a cognitive origin or they may be at a lower level within the neurophysiology of the oculomotor network, or they may be related to environment factors. In this paper we investigated one of the physiological aspects of eye movements known as post-saccadic oscillations and we show that this type of eye movement is very different between two different populations. We compared the post-saccadic oscillations recorded by a video-based eye tracker between two groups of participants: European-born and Chinese-born British students. We recorded eye movements from a group of 42 Caucasians defined as White British or White Europeans and 52 Chinese-born participants all with ages ranging from 18 to 36 during a prosaccade task. The post-saccadic oscillations were extracted from the gaze data which was compared between the two groups in terms of their first overshoot and undershoot. The results revealed that the shape of the post-saccadic oscillations varied significantly between the two groups which may indicate a difference in a multitude of genetic, cultural, physiologic, anatomical or environmental factors. We further show that the differences in the post-saccadic oscillations could influence the oculomotor characteristics such as saccade duration. We conclude that genetic, racial, biological, and/or cultural differences can affect the morphology of the eye movement data recorded and should be considered when studying eye movements and oculomotor fixation and saccadic behaviors