On the interpretation of synchronization in EEG hyperscanning studies:a cautionary note

EEG Hyperscanning is a method for studying two or more individuals simultaneously with the objective of elucidating how co-variations in their neural activity (i.e., hyperconnectivity) are influenced by their behavioral and social interactions. The aim of this study was to compare the performance of different hyper-connectivity measures using (i) simulated data, where the degree of coupling could be systematically manipulated, and (ii) individually recorded human EEG combined into pseudo-pairs of participants where no hyper-connections could exist. With simulated data we found that each of the most widely used measures of hyperconnectivity were biased and detected hyper-connections where none existed. With pseudo-pairs of human data we found spurious hyper-connections that arose because there were genuine similarities between the EEG recorded from different people independently but under the same experimental conditions. Specifically, there were systematic differences between experimental conditions in terms of the rhythmicity of the EEG that were common across participants. As any imbalance between experimental conditions in terms of stimulus presentation or movement may affect the rhythmicity of the EEG, this problem could apply in many hyperscanning contexts. Furthermore, as these spurious hyper-connections reflected real similarities between the EEGs, they were not Type-1 errors that could be overcome by some appropriate statistical control. However, some measures that have not previously been used in hyperconnectivity studies, notably the circular correlation co-efficient (CCorr), were less susceptible to detecting spurious hyper-connections of this type. The reason for this advantage in performance is discussed and the use of the CCorr as an alternative measure of hyperconnectivity is advocated. © 2013 Burgess

How conventional visual representations of time-frequency analyses bias our perception of EEG/MEG signals and what to do about it

Time-frequency decompositions of the EEG/MEG have become such a familiar part of the cognitive neuroscience landscape over the past two decades that their appearance no longer seems remarkable. But to those of us who laboured in the days when the signal analysis toolbox contained Fourier analysis, event-related potentials and not much else, the arrival of time-frequency decompositions was little short of revolutionary. With their introduction, complex information about both the timing and frequency of changes in the EEG/MEG could be presented in the visually attractive format of time-frequency plots (TFPs). Like maps, with time on the abscissa, frequency on the ordinate and a colour or grey scale to indicate the amplitude or power at each time-frequency location, TFPs provide a convenient and efficient way to represent a large amount of detailed information in an easily digestible format and, for that, they are to be commended. Yet, despite all these benefits, it is my contention that TFPs, in the format most commonly seen in journal articles and at conferences, systematically distort and bias our perception of the EEG/MEG signals that they are supposed to help us understand. Specifically, my contention is that TFPs are biased by the use of linear frequency scales. Linear frequency scales distort our perception of the EEG/MEG signal by placing far too much emphasis on the high frequency components of the signal, where there is very little energy, and far too little emphasis on the lower frequencies where the biggest changes are seen. This disproportionate focus on high frequencies confers a degree of significance to the gamma band that is not justified by the evidence

Requirements Analysis for Digital Supply Chain Compliance Management Platforms: Case of German Meat Industry

© 2023 The Authors. Published by Elsevier. This is an open access article under the Creative Commons Attribution-NonCommercial-NoDerivatives CC BY-NC-ND licence, https://creativecommons.org/licenses/by-nc-nd/4.0/The food industry faces increasing challenges in compliance management due to complexities such as evolving stakeholder demands and food industry standards. Digital compliance management platforms can support food supply chains in managing these complexities. It is important to capture the requirements across food supply chains to provide digital compliance management platforms that meet stakeholder needs within the chains. The study aimed to investigate the stakeholder-driven requirements of digital supply chain compliance management platforms within the German meat industry. The study was qualitative through the Delphi study approach. Prior to the Delphi study, stakeholder mapping was used to select the participants who are experts actively engaged with digital meat compliance platforms. In round 1 of the Delphi study, participants were asked to review the relevance of 51 existing requirements from a fresh fruit and vegetable digital compliance platform, with 50 requirements reaching full consensus among the participants. In the same round, the participants put nine additional requirements. In round 2 of the Delphi study, participants were asked to prioritise the nine additional requirements. Some requirements, like database connection, document versioning, and automatic document analysis, were found to influence user satisfaction, while others were less significant. This research shows that requirements transfer from the fresh produce sector to the meat sector is plausible. The transfer should recognise common requirements across sectors and incorporate those specific to the meat sector for improved user satisfaction.Peer reviewe

Towards a unified understanding of event-related changes in the EEG:the Firefly model of synchronization through cross-frequency phase modulation

Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing

Hypnotic induction is followed by state-like changes in the organization of EEG functional connectivity in the theta and beta frequency bands in high-hypnotically susceptible individuals

Altered state theories of hypnosis posit that a qualitatively distinct state of mental processing, which emerges in those with high hypnotic susceptibility following a hypnotic induction, enables the generation of anomalous experiences in response to specific hypnotic suggestions. If so then such a state should be observable as a discrete pattern of changes to functional connectivity (shared information) between brain regions following a hypnotic induction in high but not low hypnotically susceptible participants. Twenty-eight channel EEG was recorded from 12 high susceptible (highs) and 11 low susceptible (lows) participants with their eyes closed prior to and following a standard hypnotic induction. The EEG was used to provide a measure of functional connectivity using both coherence (COH) and the imaginary component of coherence (iCOH), which is insensitive to the effects of volume conduction. COH and iCOH were calculated between all electrode pairs for the frequency bands: delta (0.1-3.9 Hz), theta (4-7.9 Hz) alpha (8-12.9 Hz), beta1 (13-19.9 Hz), beta2 (20-29.9 Hz) and gamma (30-45 Hz). The results showed that there was an increase in theta iCOH from the pre-hypnosis to hypnosis condition in highs but not lows with a large proportion of significant links being focused on a central-parietal hub. There was also a decrease in beta1 iCOH from the pre-hypnosis to hypnosis condition with a focus on a fronto-central and an occipital hub that was greater in high compared to low susceptibles. There were no significant differences for COH or for spectral band amplitude in any frequency band. The results are interpreted as indicating that the hypnotic induction elicited a qualitative change in the organization of specific control systems within the brain for high as compared to low susceptible participants. This change in the functional organization of neural networks is a plausible indicator of the much theorized "hypnotic-state". © 2014 Jamieson and Burgess

A facial expression for anxiety.

Anxiety and fear are often confounded in discussions of human emotions. However, studies of rodent defensive reactions under naturalistic conditions suggest anxiety is functionally distinct from fear. Unambiguous threats, such as predators, elicit flight from rodents (if an escape-route is available), whereas ambiguous threats (e.g., the odor of a predator) elicit risk assessment behavior, which is associated with anxiety as it is preferentially modulated by anti-anxiety drugs. However, without human evidence, it would be premature to assume that rodent-based psychological models are valid for humans. We tested the human validity of the risk assessment explanation for anxiety by presenting 8 volunteers with emotive scenarios and asking them to pose facial expressions. Photographs and videos of these expressions were shown to 40 participants who matched them to the scenarios and labeled each expression. Scenarios describing ambiguous threats were preferentially matched to the facial expression posed in response to the same scenario type. This expression consisted of two plausible environmental-scanning behaviors (eye darts and head swivels) and was labeled as anxiety, not fear. The facial expression elicited by unambiguous threat scenarios was labeled as fear. The emotion labels generated were then presented to another 18 participants who matched them back to photographs of the facial expressions. This back-matching of labels to faces also linked anxiety to the environmental-scanning face rather than fear face. Results therefore suggest that anxiety produces a distinct facial expression and that it has adaptive value in situations that are ambiguously threatening, supporting a functional, risk-assessing explanation for human anxiet

TETRA mobile radios interfere with electroencephalography recording equipment

We observed an anomaly in the human electroencephalogram (EEG) associated with exposure to terrestrial trunked radio (TETRA) Radiofrequency Fields (RF). Here, we characterize the time and frequency components of the anomaly and demonstrate that it is an artefact caused by TETRA RF interfering with the EEG recording equipment and not by any direct or indirect effect on the brain

Financial support differentially aids retention of students from households with lower incomes: a UK case study

Around the world each year, large sums of money are expended in helping students access higher education institutions (HEIs), but there is remarkably little evidence to show whether this investment is effective or not. Here we use data from a UK university to investigate the relationship between financial support and continuation of students beyond their first year of study. As a result of changing scholarship policies over the course of three years, a natural experiment was created that allowed us to investigate the effect of financial support on rates of withdrawal of students from households with different incomes. Controlling for multiple demographic and attainment factors (age, gender, ethnic grouping, disability, nationality, household income, prior educational attainment, and local Higher Education participation rates), the data suggest that scholarships improved student retention, but principally for those students from households with low and intermediate incomes. Interestingly, the value of the scholarships, which varied from £500 to £3,000, did not have a measurable effect on withdrawal. We also found that some students who appeared to be eligible for a scholarship and would likely have benefitted from it did not receive one, and we discuss the reasons why this might be so. These results have important implications for scholarship policies in Higher Education internationally; to maximise impact, scholarships should be awarded to those most in financial need

Optimising the impact of a multi-intervention outreach programme on progression to Higher Education:recommendations for future practice and research

Despite substantial financial commitment to widening participation activities internationally, robust evidence demonstrating ‘what works’ in facilitating disadvantaged learners to access Higher Education (HE) is remarkably sparse. Much effort has been directed at measuring immediate post-intervention changes in the aspirations, attitudes and behaviours thought to drive access to HE, rather than actual access itself. Here, we present an innovative quasi-experimental study of a multi-intervention outreach programme (UniConnect) consisting of 1,386 learners from the Aimhigher West Midlands database whose HE application results were known, while controlling for multiple variables, including estimates of deprivation. The results showed that any engagement with UniConnect, no matter how limited, was associated with an improved chance of achieving a place in HE, but the type of engagement, the extent of engagement and the combination of types of engagement all mattered. The more learners engaged with UniConnect, the greater were their chances of HE acceptance, but the benefit of each additional engagement beyond five or six engagements was small. To our knowledge, these findings are the first to indicate the number, type and combinations of interventions that are most effective in supporting progression to HE. These results therefore have important implications for future practice, enabling funding for such work to be used for optimal impact. Furthermore, we found large differences in success between schools, even when controlling for several other variables; a finding which has important implications for future evaluation research