Neurodesk: an accessible, flexible and portable data analysis environment for reproducible neuroimaging.

Neuroimaging research requires purpose-built analysis software, which is challenging to install and may produce different results across computing environments. The community-oriented, open-source Neurodesk platform ( https://www.neurodesk.org/ ) harnesses a comprehensive and growing suite of neuroimaging software containers. Neurodesk includes a browser-accessible virtual desktop, command-line interface and computational notebook compatibility, allowing for accessible, flexible, portable and fully reproducible neuroimaging analysis on personal workstations, high-performance computers and the cloud.

Neurodesk: An accessible, flexible, and portable data analysis environment for reproducible neuroimaging.

Neuroimaging data analysis often requires purpose-built software, which can be challenging to install and may produce different results across computing environments. Beyond being a roadblock to neuroscientists, these issues of accessibility and portability can hamper the reproducibility of neuroimaging data analysis pipelines. Here, we introduce the Neurodesk platform, which harnesses software containers to support a comprehensive and growing suite of neuroimaging software (https://www.neurodesk.org/). Neurodesk includes a browser-accessible virtual desktop environment and a command line interface, mediating access to containerized neuroimaging software libraries on various computing platforms, including personal and high-performance computers, cloud computing and Jupyter Notebooks. This community-oriented, open-source platform enables a paradigm shift for neuroimaging data analysis, allowing for accessible, flexible, fully reproducible, and portable data analysis pipelines.

Optimising the classification of feature-based attention in frequency-tagged electroencephalography data.

Brain-computer interfaces (BCIs) are a rapidly expanding field of study and require accurate and reliable real-time decoding of patterns of neural activity. These protocols often exploit selective attention, a neural mechanism that prioritises the sensory processing of task-relevant stimulus features (feature-based attention) or task-relevant spatial locations (spatial attention). Within the visual modality, attentional modulation of neural responses to different inputs is well indexed by steady-state visual evoked potentials (SSVEPs). These signals are reliably present in single-trial electroencephalography (EEG) data, are largely resilient to common EEG artifacts, and allow separation of neural responses to numerous concurrently presented visual stimuli. To date, efforts to use single-trial SSVEPs to classify visual attention for BCI control have largely focused on spatial attention rather than feature-based attention. Here, we present a dataset that allows for the development and benchmarking of algorithms to classify feature-based attention using single-trial EEG data. The dataset includes EEG and behavioural responses from 30 healthy human participants who performed a feature-based motion discrimination task on frequency tagged visual stimuli.

Implicit Neurofeedback Training of Feature-Based Attention Promotes Biased Sensory Processing during Integrative Decision-Making.

Complex perceptual decisions, in which information must be integrated across multiple sources of evidence, are ubiquitous but are not well understood. Such decisions rely on sensory processing of each individual source of evidence, and are therefore vulnerable to bias if sensory processing resources are disproportionately allocated among visual inputs. To investigate this, we developed an implicit neurofeedback protocol embedded within a complex decision-making task to bias sensory processing in favor of one source of evidence over another. Human participants of both sexes (N = 30) were asked to report the average motion direction across two fields of oriented moving bars. Bars of different orientations flickered at different frequencies, thus inducing steady-state visual evoked potentials. Unbeknownst to participants, neurofeedback was implemented to implicitly reward attention to a specific "trained" orientation (rather than any particular motion direction). As attentional selectivity for this orientation increased, the motion coherence of both fields of bars increased, making the task easier without altering the relative reliability of the two sources of evidence. Critically, these neurofeedback trials were alternated with "test" trials in which motion coherence was not contingent on attentional selectivity, allowing us to assess the training efficacy. The protocol successfully biased sensory processing, resulting in earlier and stronger encoding of the trained evidence source. In turn, this evidence was weighted more heavily in behavioral and neural representations of the integrated average, although the two sources of evidence were always matched in reliability. These results demonstrate how biases in sensory processing can impact integrative decision-making processes.SIGNIFICANCE STATEMENT Many everyday decisions require active integration of different sources of sensory information, such as deciding when it is safe to cross a road, yet little is known about how the brain prioritizes sensory sources in the service of adaptive behavior, or whether such decisions can be altered through learning. Here we addressed these questions using a novel behavioral protocol that provided observers with real-time feedback of their own brain activity patterns in which sensory processing was implicitly biased toward a subset of the available information. We show that, while such biases are a normal and adaptive mechanism for humans to process complex visual information, they can also contribute to suboptimal decision-making.

Joint control of visually guided actions involves concordant increases in behavioural and neural coupling.

It is often necessary for individuals to coordinate their actions with others. In the real world, joint actions rely on the direct observation of co-actors and rhythmic cues. But how are joint actions coordinated when such cues are unavailable? To address this question, we recorded brain activity while pairs of participants guided a cursor to a target either individually (solo control) or together with a partner (joint control) from whom they were physically and visibly separated. Behavioural patterns revealed that joint action involved real-time coordination between co-actors and improved accuracy for the lower performing co-actor. Concurrent neural recordings and eye tracking revealed that joint control affected cognitive processing across multiple stages. Joint control involved increases in both behavioural and neural coupling - both quantified as interpersonal correlations - peaking at action completion. Correspondingly, a neural offset response acted as a mechanism for and marker of interpersonal neural coupling, underpinning successful joint actions.

Optimising non-invasive brain-computer interface systems for free communication between naïve human participants.

Free communication is one of the cornerstones of modern civilisation. While manual keyboards currently allow us to interface with computers and manifest our thoughts, a next frontier is communication without manual input. Brain-computer interface (BCI) spellers often achieve this by decoding patterns of neural activity as users attend to flickering keyboard displays. To date, the highest performing spellers report typing rates of ~10.00 words/minute. While impressive, these rates are typically calculated for experienced users repetitively typing single phrases. It is therefore not clear whether naïve users are able to achieve such high rates with the added cognitive load of genuine free communication, which involves continuously generating and spelling novel words and phrases. In two experiments, we developed an open-source, high-performance, non-invasive BCI speller and examined its feasibility for free communication. The BCI speller required users to focus their visual attention on a flickering keyboard display, thereby producing unique cortical activity patterns for each key, which were decoded using filter-bank canonical correlation analysis. In Experiment 1, we tested whether seventeen naïve users could maintain rapid typing during prompted free word association. We found that information transfer rates were indeed slower during this free communication task than during typing of a cued character sequence. In Experiment 2, we further evaluated the speller's efficacy for free communication by developing a messaging interface, allowing users to engage in free conversation. The results showed that free communication was possible, but that information transfer was reduced by voluntary textual corrections and turn-taking during conversation. We evaluated a number of factors affecting the suitability of BCI spellers for free communication, and make specific recommendations for improving classification accuracy and usability. Overall, we found that developing a BCI speller for free communication requires a focus on usability over reduced character selection time, and as such, future performance appraisals should be based on genuine free communication scenarios.

Differential Deployment of Visual Attention During Interactive Approach and Avoidance Behavior.

The ability to coordinate approach and avoidance actions in dynamic environments represents the boundary between extinction and the continued survival of many animal species. It is therefore crucial that sensory systems allocate limited attentional resources to the most relevant information to facilitate planning and execution of appropriate actions. Prominent theories of how attention regulates visual processing focus on the distinction between behaviorally relevant and irrelevant visual inputs. To date, however, no study has directly compared the deployment of attention to visual inputs relevant for approach and avoidance behaviors, which naturally occur in dynamic, interactive environments. In two experiments, we combined electroencephalography, frequency tagging, and eye gaze measures to investigate whether the deployment of visual selective attention differs for items relevant for approach and avoidance actions. Participants maneuvered a cursor to approach and avoid contact with moving items in a continuous interactive task. The results indicated that while the approach and avoidance tasks recruited equivalent attentional resources overall, attentional biases were directed toward task-relevant items during approach, and away from task-relevant items during avoidance. We conclude that the deployment of visual attention is guided not only by relevance to a behavioral goal, but also by the nature of that goal.

Do Sitting, Standing, or Treadmill Desks Impact Psychobiological Indicators of Work Productivity?

BACKGROUND: This pilot study investigated the links between psychobiological indicators of work productivity, prolonged desk sitting, and conditions whereby office workers were able to interrupt sitting using a sit-stand or treadmill desk. METHODS: Twenty participants visited our laboratory and completed their own desk work in counterbalanced sit-only, sit-stand (Varidesk Pro Plus 48™), and sit-walk conditions (Infiniti TR1200-DTS™). Steady-state visually evoked potentials calculated from electroencephalography recordings during a set task at the end of the workday assessed attentional resource. Salivary cortisol samples were taken during the morning and afternoon to measure stress response. Within-subject analyses were used to compare work productivity indicators relative to condition. RESULTS: No significant differences in mean steady-state visually evoked potential amplitude were observed, although attentional resource allocation was found to be the most effective following the sit-stand [1.01 (0.46) µV] compared with the sit-walk [0.9 (0.28) µV] and sit-only [0.91 (0.32) µV] conditions. The mean magnitude of decrease in cortisol was most apparent when workers used treadmill (1.5 nmol/L; P = .007) and sit-stand (1.6 nmol/L; P = .001) desks, and least evident in the sit-only condition (1.0 nmol/L; P = .146). CONCLUSIONS: The findings highlight the potential benefits of standing or active deskwork to the allocation of attentional resources and the regulation of stress.