Ellen Seiss - Academia.edu (original) (raw)

Papers by Ellen Seiss

PLOS ONE, Apr 13, 2023

This paper describes the development and validation of 3D Affective Virtual environments and Even... more This paper describes the development and validation of 3D Affective Virtual environments and Event Library (AVEL) for affect induction in Virtual Reality (VR) settings with an online survey; a cost-effective method for remote stimuli validation which has not been sufficiently explored. Three virtual office-replica environments were designed to induce negative, neutral and positive valence. Each virtual environment also had several affect inducing events/objects. The environments were validated using an online survey containing videos of the virtual environments and pictures of the events/objects. They survey was conducted with 67 participants. Participants were instructed to rate their perceived levels of valence and arousal for each virtual environment (VE), and separately for each event/object. They also rated their perceived levels of presence for each VE, and they were asked how well they remembered the events/objects presented in each VE. Finally, an alexithymia questionnaire was administered at the end of the survey. User ratings were analysed and successfully validated the expected affect and presence levels of each VE and affect ratings for each event/object. Our results demonstrate the effectiveness of the online validation of VE material in affective and cognitive neuroscience and wider research settings as a good scientific practice for future affect induction VR studies.

Immersive technologies offer the potential to drive engagement and create exciting experiences. A... more Immersive technologies offer the potential to drive engagement and create exciting experiences. A better understanding of the emotional state of the user within immersive experiences can assist in healthcare interventions and the evaluation of entertainment technologies. This work describes a feasibility study to explore the effect of affective video content on heart-rate recordings for Virtual Reality applications. A lowcost re�lected-mode photoplethysmographic sensor and an electrocardiographic chest-belt sensor were attached on a novel non-invasive wearable interface specially designed for this study. 11 participants responses were analysed, and heart-rate metrics were used for arousal classi�ication. The reported results demonstrate that the fusion of physiological signals yields to signi�icant performance improvement; and hence the feasibility of our new approach.

Descriptors: glucose, LRP, flanker task Behavioural studies suggest that elevated blood glucose c... more Descriptors: glucose, LRP, flanker task Behavioural studies suggest that elevated blood glucose concentrations accelerate response times in complex tasks (Owens and Benton, 2004, Neuropsychobiology). With the present study we aimed to explore the mechanisms subserving elevated blood glucose effects (7 mmol/litre versus fasting levels of 5 mmol/litre) by studying EEG-derived indices of sensorimotor processing. More specifically, the Eriksen flanker task was used to examine glucose-dependent modulations of the P300, the stimulus lateralized readiness potentials (LRPs), and response-locked LRP, to see whether enhanced blood glucose levels affect stimulus evaluation, response planning, and response selection respectively. 10 participants took part in a within-participant double-blind 2-session experiment where either glucose (25 g) or placebo drinks were administered. Initial data suggests slower reaction times, higher error rates and delayed stimulus-locked LRP onset in incongruent compared to congruent and neutral trials. With placebo administration error rates were increased for the non-dominant hand but not the dominant hand; no effects were found for the EEG parameters. This suggests that hyperglycaemia does not affect senorimotor processing in the flanker task. However, the placebo-related increase in error rates together with the findings of (Donohoe and Benton, 2000) support the proposition that beneficial effects of increased blood glucose levels on cognition might only occur when cognitive demands are high.

2022 10th International Conference on Affective Computing and Intelligent Interaction (ACII)

Objective: This study investigated selective attention in people with Parkinson’s disease (PD) us... more Objective: This study investigated selective attention in people with Parkinson’s disease (PD) using the Priming-of-Popout (PoP) paradigm. Background: Attentional deficits have been previously reported in PD. The aim of this study was to investigate attentional deficits in PD with a new experimental Priming-of-Popout (PoP) paradigm that controlled for response selection deficits as a confounding variable, rarely done in previous studies. Methods: 12 nondemented and non-depressed PD patients (6466.5years, self-assessed Hoehn &Yahr: 2.4 (range:1-3.5)) and 12 age-matched controls (6365.7years) participated. The PoP paradigm is a speeded reaction time task, and the participants were instructed to respond to the shape of an odd coloured target (singleton) while ignoring three distractors displayed in another second colour. By design, this task is well- suited to examine attentional pop-out effects, because it is possible to disambiguate the effect of colour, which is an attention-driven ...

• 11 right handed, 1 left handed participant

To investigate whether salient visual singletons capture attention when they appear outside the c... more To investigate whether salient visual singletons capture attention when they appear outside the current endogenous attentional focus, we measured the N2pc component as a marker of attentional capture in a visual search task where target or nontarget singletons were presented at locations previously cued as task-relevant, or in the uncued irrelevant hemifield. In two experiments, targets were either defined by color or by a combination of color and shape. The N2pc was elicited both for attended singletons and for singletons on the uncued side, demonstrating that focused endogenous attention cannot prevent attentional capture by salient unattended visual events. However, N2pc amplitudes were larger for attended and unattended singletons that shared features with the current target, suggesting that top-down task sets modulate the capacity of visual singletons to capture attention both within and outside the current attentional focus.

Frontiers in Virtual Reality, 2022

Virtual Reality (VR) enables the simulation of ecologically validated scenarios, which are ideal ... more Virtual Reality (VR) enables the simulation of ecologically validated scenarios, which are ideal for studying behaviour in controllable conditions. Physiological measures captured in these studies provide a deeper insight into how an individual responds to a given scenario. However, the combination of the various biosensing devices presents several challenges, such as efficient time synchronisation between multiple devices, replication between participants and settings, as well as managing cumbersome setups. Additionally, important salient facial information is typically covered by the VR headset, requiring a different approach to facial muscle measurement. These challenges can restrict the use of these devices in laboratory settings. This paper describes a solution to this problem. More specifically, we introduce the emteqPRO system which provides an all-in-one solution for the collection of physiological data through a multi-sensor array built into the VR headset. EmteqPRO is a re...

Recent pandemic related events have effectively put a stop to most in-lab data collection which h... more Recent pandemic related events have effectively put a stop to most in-lab data collection which has a profound negative impact on many research fields. Online and remote data collection, without the need to travel to a laboratory, starts to be used as a valuable alternative in some scenarios. This approach does not only help to resume some research activities, it also has an enormous potential to change how research is conducted in future. With the use of our biometric sensing system for Virtual Reality (emteqGO), we designed a VR experience autonomously guiding participants through the study. The combination of hardware posted to participants, alongside software solutions handling the setup, data collection, quality assurance and upload for immediate access enables a fully remote, unsupervised approach to data collection. While this approach might be the only feasible solution for some researchers, it has also laid the groundwork for possible future direction of research where remote data collection is a new way to enhance access to participants who typically would not travel to the laboratories. In designing these solutions, we found that for unsupervised remote data collection to work effectively, setup procedures must be easy to follow to obtain high quality data and the entire process must be highly robust, reliable, and built with a high degree of redundancy. Post-pandemic, there are many benefits of an ongoing use of remote research paradigms. These include ameliorating the diversity problem afflicting current research by widening the participant pool, improved research quality by collecting data in more naturalistic environments, and improving protocol standardisation using virtual reality. CCS CONCEPTS • hardware~communication hardware, interfaces and storage~sensor devices and platforms • hardware~emerging technologies~analysis and design of emerging devices and systems~emerging tools and methodologies • Human-centered computing~Human computer interaction (HCI)~Interaction paradigms~virtual reality

BMC Medical Informatics and Decision Making, 2020

Background Despite the established evidence and theoretical advances explaining human judgments u... more Background Despite the established evidence and theoretical advances explaining human judgments under uncertainty, developments of mobile health (mHealth) Clinical Decision Support Systems (CDSS) have not explicitly applied the psychology of decision making to the study of user needs. We report on a user needs approach to develop a prototype of a mHealth CDSS for Parkinson’s disease (PD), which is theoretically grounded in the psychological literature about expert decision making and judgement under uncertainty. Methods A suite of user needs studies was conducted in 4 European countries (Greece, Italy, Slovenia, the UK) prior to the development of PD_Manager, a mHealth-based CDSS designed for Parkinson’s disease, using wireless technology. Study 1 undertook Hierarchical Task Analysis (HTA) including elicitation of user needs, cognitive demands and perceived risks/benefits (ethical considerations) associated with the proposed CDSS, through structured interviews of prescribing clinici...

Proceedings of the Workshop on Human-Habitat for Health (H3) Human-Habitat Multimodal Interaction for Promoting Health and Well-Being in the Internet of Things Era - H3 '18

Immersive technologies offer the potential to drive engagement and create exciting experiences. A... more Immersive technologies offer the potential to drive engagement and create exciting experiences. A better understanding of the emotional state of the user within immersive experiences can assist in healthcare interventions and the evaluation of entertainment technologies. This work describes a feasibility study to explore the effect of affective video content on heart-rate recordings for Virtual Reality applications. A low-cost reflected-mode photoplethysmographic sensor and an electrocardiographic chest-belt sensor were attached on a novel non-invasive wearable interface specially designed for this study. 11 participants responses were analysed, and heart-rate metrics were used for arousal classification. The reported results demonstrate that the fusion of physiological signals yields to significant performance improvement; and hence the feasibility of our new approach.

Journal of Experimental Psychology: Human Perception and Performance

The functional equivalence (FE) hypothesis suggests motor imagery (MI) is comparable with the pla... more The functional equivalence (FE) hypothesis suggests motor imagery (MI) is comparable with the planning stages of action. A strong interpretation of this hypothesis suggests MI can prime subsequent actions in a way that should be indistinguishable from motor preparation (MP). Alternatively, MI could involve more richly informative motor plans than MP, producing different effects on the performance of subsequent actions. Although past research has demonstrated MI can prime action, little research has directly compared it with MP, and so the value of a strong FE interpretation for understanding MI remains unclear. In the present study, a precueing paradigm was used in 4 experiments, and congruency effects of MI and MP on subsequent action were compared. Precues instructed participants to prepare for (MP condition) or imagine (MI condition) a corresponding response prior to making a real response to the imperative stimulus, which was either congruent or incongruent with the precue information. Experiment 1 provided first evidence favoring our alternative hypothesis that imagery-primed responses should result in larger response priming effects than prepared-responses, suggesting that MI might involve more richly informative motor plans than preparation for action alone. In experiment 2, we manipulated interstimulus foreperiods and replicated the MI-priming effect, showing it to be independent of differences in temporal uncertainty between MI and MP. Experiment 3 showed the MI-priming effect is present in both foot and finger responses, and Experiment 4 suggested the larger congruency effects in the MI condition could not be explained by differences in cognitive load between MI and MP. These results suggest that a strong FE hypothesis does not hold. Findings are discussed in line with the predictive processing models of action and MI. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Behavioural studies have indicated that response times on complex reaction time tasks are faster ... more Behavioural studies have indicated that response times on complex reaction time tasks are faster if blood glucose concentrations are slightly elevated above normal (Donohoe & Benton, 2000). Such tasks involve several cognitive processing stages but it is not clear which of these stages are speeded after glucose administration. In order to investigate this problem we have used a double blind repeated measures design for the administration of glucose and placebo drinks. Participants performed a Flanker task while EEG was recorded as a physiological measure. More specifically, we used a Flanker task that required participants to respond to either left or right pointing central arrows by pressing a left or a right button, respectively. In addition on each trial there are extra arrows surrounding the central arrow which all either pointed in the same (congruent condition) or opposite (incongruent condition) direction as the central arrow or they were lines without an arrow head (neutral ...

Stroke patients with motor deficits often report daytime sleepiness. While slowing of the EEG dur... more Stroke patients with motor deficits often report daytime sleepiness. While slowing of the EEG during wakefulness has been shown after stroke, it is unknown if and how this is linked to their perception of sleepiness. Using waking EEG and a motor task (associated with mild sleepiness), we examined: 1) differences in the frequency composition and lateralisation of the EEG between stroke patients and controls, and 2) the relationship between the EEG and subjective sleepiness ratings. EEG and Karolinska Sleepiness Scale (KSS) data were collected from 15 right hemispheric stroke patients and 15 matched controls before and after a motor priming task. Frequency analysis was performed on C3 and C4 channels. Prior to the task, the stroke group revealed increased power density below 10 Hz compared to controls for both hemispheres, with more pronounced effects within the lesioned hemisphere. The motor task significantly increased KSS scores in both groups. Increased beta and alpha activity was...

The uses of Virtual reality are constantly evolving, from healthcare treatments to evaluating com... more The uses of Virtual reality are constantly evolving, from healthcare treatments to evaluating commercial products, all of which would benefit from a better understanding of the emotional state of the individual. There is ongoing research into developing specially adapted methods for the recognition of the user’s affect while immersed within Virtual Reality. This paper outlines the approaches attempted and the available methodologies that embed sensors into wearable devices for real-time affect detection. These emerging technologies are introducing innovative ways of studying and interpreting emotion related data produced within immersive experiences

The current practical restraints for facial expression recognition in Virtual Reality (VR) led to... more The current practical restraints for facial expression recognition in Virtual Reality (VR) led to the development of a novel wearable interface called Faceteq. Our team designed a pilot feasibility study to explore the effect of spontaneous facial expressions on eight EMG sensors, incorporated on the Faceteq interface. Thirty-four participants took part in the study where they watched a sequence of video stimuli while self-rating their emotional state. After a specifically designed signal pre-processing, we aimed to classify the responses into three classes (negative, neutral, positive). A C-SVM classifier was cross-validated for each participant, reaching an out-of-sample average accuracy of 82.5%. These preliminary results have encouraged us to enlarge our dataset and incorporate data from different physiological signals to achieve automatic detection of combined arousal and valence states for VR applications.

Frontiers in Human Neuroscience, 2011

Background Flanker Congruency Effect-We observed the typical flanker effect; i.e. responses for i... more Background Flanker Congruency Effect-We observed the typical flanker effect; i.e. responses for incongruent trials were slower than in congruent trials (p < 0.01). Drink Effect-In the first block, RTs were slower in the glucose relative to the placebo session (p=0.03). Flanker congruency effects were not modulated by the Drink type (p>.05). Drink Effect dependent on Drink Order-In the first block, the drink effect was further modulated by the factor drink order (p=0.01). More specifically, RTs in the glucose session were slower than in the placebo session when glucose was given before placebo (p=0.02). However, this was not the case when placebo was before glucose (p=0.56). HHSHH Experiment 1 Arrow Flanker Study-Our findings suggest that glucose may slow RTs when participants are inexperienced with a sensorimotor task (1 st block effects). Once experience is gained this effect vanishes, this is possibly because sensorimotor processing becomes too automatic as S-R association is strengthened over successive trials. Experiment 2 Letter Flanker Study-This experiment aimed to keep S-R association low for the duration of the experiment by using novel stimuli on successive blocks of trials. By doing this we demonstrated that glucose can consistently slow RTs on a sensorimotor task for a prolonged period of time (at least 30 minutes). General Discussion-Together both experiments suggest that when S-R associations are low that glucose can slow RTs. In terms of physiology, an increase in glucose metabolism as a result of glucose drink administration may cause oxidative stress. This can impair Na+/K+ channels in the neural membrane and slow neural conduction velocity, and thereby might slow RTs.

One of the potential explanations for negative compatibility effects (NCE) in subliminal motor pr... more One of the potential explanations for negative compatibility effects (NCE) in subliminal motor priming tasks has been perceptual prime-target interactions. Here, we investigate whether the characteristic tri-phasic LRP pattern associated with the NCE is caused by these prime-target interactions. We found that both the prime-related phase and the critical reversal phase remain present even on trials where the target is omitted, confirming they are elicited by the prime and mask, not by prime-target interactions. We also report that shape and size of the reversal phase are associated with response speed, consistent with a causal role for the reversal for the subsequent response latency. Additionally, we analysed sequential modulation of the NCE by previous conflicting events, even though such conflict is subliminal. In accordance with previous literature, this modulation is small but significant.

PLOS ONE, Apr 13, 2023

This paper describes the development and validation of 3D Affective Virtual environments and Even... more This paper describes the development and validation of 3D Affective Virtual environments and Event Library (AVEL) for affect induction in Virtual Reality (VR) settings with an online survey; a cost-effective method for remote stimuli validation which has not been sufficiently explored. Three virtual office-replica environments were designed to induce negative, neutral and positive valence. Each virtual environment also had several affect inducing events/objects. The environments were validated using an online survey containing videos of the virtual environments and pictures of the events/objects. They survey was conducted with 67 participants. Participants were instructed to rate their perceived levels of valence and arousal for each virtual environment (VE), and separately for each event/object. They also rated their perceived levels of presence for each VE, and they were asked how well they remembered the events/objects presented in each VE. Finally, an alexithymia questionnaire was administered at the end of the survey. User ratings were analysed and successfully validated the expected affect and presence levels of each VE and affect ratings for each event/object. Our results demonstrate the effectiveness of the online validation of VE material in affective and cognitive neuroscience and wider research settings as a good scientific practice for future affect induction VR studies.

Immersive technologies offer the potential to drive engagement and create exciting experiences. A... more Immersive technologies offer the potential to drive engagement and create exciting experiences. A better understanding of the emotional state of the user within immersive experiences can assist in healthcare interventions and the evaluation of entertainment technologies. This work describes a feasibility study to explore the effect of affective video content on heart-rate recordings for Virtual Reality applications. A lowcost re�lected-mode photoplethysmographic sensor and an electrocardiographic chest-belt sensor were attached on a novel non-invasive wearable interface specially designed for this study. 11 participants responses were analysed, and heart-rate metrics were used for arousal classi�ication. The reported results demonstrate that the fusion of physiological signals yields to signi�icant performance improvement; and hence the feasibility of our new approach.

Descriptors: glucose, LRP, flanker task Behavioural studies suggest that elevated blood glucose c... more Descriptors: glucose, LRP, flanker task Behavioural studies suggest that elevated blood glucose concentrations accelerate response times in complex tasks (Owens and Benton, 2004, Neuropsychobiology). With the present study we aimed to explore the mechanisms subserving elevated blood glucose effects (7 mmol/litre versus fasting levels of 5 mmol/litre) by studying EEG-derived indices of sensorimotor processing. More specifically, the Eriksen flanker task was used to examine glucose-dependent modulations of the P300, the stimulus lateralized readiness potentials (LRPs), and response-locked LRP, to see whether enhanced blood glucose levels affect stimulus evaluation, response planning, and response selection respectively. 10 participants took part in a within-participant double-blind 2-session experiment where either glucose (25 g) or placebo drinks were administered. Initial data suggests slower reaction times, higher error rates and delayed stimulus-locked LRP onset in incongruent compared to congruent and neutral trials. With placebo administration error rates were increased for the non-dominant hand but not the dominant hand; no effects were found for the EEG parameters. This suggests that hyperglycaemia does not affect senorimotor processing in the flanker task. However, the placebo-related increase in error rates together with the findings of (Donohoe and Benton, 2000) support the proposition that beneficial effects of increased blood glucose levels on cognition might only occur when cognitive demands are high.

2022 10th International Conference on Affective Computing and Intelligent Interaction (ACII)

Objective: This study investigated selective attention in people with Parkinson’s disease (PD) us... more Objective: This study investigated selective attention in people with Parkinson’s disease (PD) using the Priming-of-Popout (PoP) paradigm. Background: Attentional deficits have been previously reported in PD. The aim of this study was to investigate attentional deficits in PD with a new experimental Priming-of-Popout (PoP) paradigm that controlled for response selection deficits as a confounding variable, rarely done in previous studies. Methods: 12 nondemented and non-depressed PD patients (6466.5years, self-assessed Hoehn &Yahr: 2.4 (range:1-3.5)) and 12 age-matched controls (6365.7years) participated. The PoP paradigm is a speeded reaction time task, and the participants were instructed to respond to the shape of an odd coloured target (singleton) while ignoring three distractors displayed in another second colour. By design, this task is well- suited to examine attentional pop-out effects, because it is possible to disambiguate the effect of colour, which is an attention-driven ...

• 11 right handed, 1 left handed participant

To investigate whether salient visual singletons capture attention when they appear outside the c... more To investigate whether salient visual singletons capture attention when they appear outside the current endogenous attentional focus, we measured the N2pc component as a marker of attentional capture in a visual search task where target or nontarget singletons were presented at locations previously cued as task-relevant, or in the uncued irrelevant hemifield. In two experiments, targets were either defined by color or by a combination of color and shape. The N2pc was elicited both for attended singletons and for singletons on the uncued side, demonstrating that focused endogenous attention cannot prevent attentional capture by salient unattended visual events. However, N2pc amplitudes were larger for attended and unattended singletons that shared features with the current target, suggesting that top-down task sets modulate the capacity of visual singletons to capture attention both within and outside the current attentional focus.

Frontiers in Virtual Reality, 2022

Virtual Reality (VR) enables the simulation of ecologically validated scenarios, which are ideal ... more Virtual Reality (VR) enables the simulation of ecologically validated scenarios, which are ideal for studying behaviour in controllable conditions. Physiological measures captured in these studies provide a deeper insight into how an individual responds to a given scenario. However, the combination of the various biosensing devices presents several challenges, such as efficient time synchronisation between multiple devices, replication between participants and settings, as well as managing cumbersome setups. Additionally, important salient facial information is typically covered by the VR headset, requiring a different approach to facial muscle measurement. These challenges can restrict the use of these devices in laboratory settings. This paper describes a solution to this problem. More specifically, we introduce the emteqPRO system which provides an all-in-one solution for the collection of physiological data through a multi-sensor array built into the VR headset. EmteqPRO is a re...

Recent pandemic related events have effectively put a stop to most in-lab data collection which h... more Recent pandemic related events have effectively put a stop to most in-lab data collection which has a profound negative impact on many research fields. Online and remote data collection, without the need to travel to a laboratory, starts to be used as a valuable alternative in some scenarios. This approach does not only help to resume some research activities, it also has an enormous potential to change how research is conducted in future. With the use of our biometric sensing system for Virtual Reality (emteqGO), we designed a VR experience autonomously guiding participants through the study. The combination of hardware posted to participants, alongside software solutions handling the setup, data collection, quality assurance and upload for immediate access enables a fully remote, unsupervised approach to data collection. While this approach might be the only feasible solution for some researchers, it has also laid the groundwork for possible future direction of research where remote data collection is a new way to enhance access to participants who typically would not travel to the laboratories. In designing these solutions, we found that for unsupervised remote data collection to work effectively, setup procedures must be easy to follow to obtain high quality data and the entire process must be highly robust, reliable, and built with a high degree of redundancy. Post-pandemic, there are many benefits of an ongoing use of remote research paradigms. These include ameliorating the diversity problem afflicting current research by widening the participant pool, improved research quality by collecting data in more naturalistic environments, and improving protocol standardisation using virtual reality. CCS CONCEPTS • hardware~communication hardware, interfaces and storage~sensor devices and platforms • hardware~emerging technologies~analysis and design of emerging devices and systems~emerging tools and methodologies • Human-centered computing~Human computer interaction (HCI)~Interaction paradigms~virtual reality

BMC Medical Informatics and Decision Making, 2020

Background Despite the established evidence and theoretical advances explaining human judgments u... more Background Despite the established evidence and theoretical advances explaining human judgments under uncertainty, developments of mobile health (mHealth) Clinical Decision Support Systems (CDSS) have not explicitly applied the psychology of decision making to the study of user needs. We report on a user needs approach to develop a prototype of a mHealth CDSS for Parkinson’s disease (PD), which is theoretically grounded in the psychological literature about expert decision making and judgement under uncertainty. Methods A suite of user needs studies was conducted in 4 European countries (Greece, Italy, Slovenia, the UK) prior to the development of PD_Manager, a mHealth-based CDSS designed for Parkinson’s disease, using wireless technology. Study 1 undertook Hierarchical Task Analysis (HTA) including elicitation of user needs, cognitive demands and perceived risks/benefits (ethical considerations) associated with the proposed CDSS, through structured interviews of prescribing clinici...

Proceedings of the Workshop on Human-Habitat for Health (H3) Human-Habitat Multimodal Interaction for Promoting Health and Well-Being in the Internet of Things Era - H3 '18

Immersive technologies offer the potential to drive engagement and create exciting experiences. A... more Immersive technologies offer the potential to drive engagement and create exciting experiences. A better understanding of the emotional state of the user within immersive experiences can assist in healthcare interventions and the evaluation of entertainment technologies. This work describes a feasibility study to explore the effect of affective video content on heart-rate recordings for Virtual Reality applications. A low-cost reflected-mode photoplethysmographic sensor and an electrocardiographic chest-belt sensor were attached on a novel non-invasive wearable interface specially designed for this study. 11 participants responses were analysed, and heart-rate metrics were used for arousal classification. The reported results demonstrate that the fusion of physiological signals yields to significant performance improvement; and hence the feasibility of our new approach.

Journal of Experimental Psychology: Human Perception and Performance

The functional equivalence (FE) hypothesis suggests motor imagery (MI) is comparable with the pla... more The functional equivalence (FE) hypothesis suggests motor imagery (MI) is comparable with the planning stages of action. A strong interpretation of this hypothesis suggests MI can prime subsequent actions in a way that should be indistinguishable from motor preparation (MP). Alternatively, MI could involve more richly informative motor plans than MP, producing different effects on the performance of subsequent actions. Although past research has demonstrated MI can prime action, little research has directly compared it with MP, and so the value of a strong FE interpretation for understanding MI remains unclear. In the present study, a precueing paradigm was used in 4 experiments, and congruency effects of MI and MP on subsequent action were compared. Precues instructed participants to prepare for (MP condition) or imagine (MI condition) a corresponding response prior to making a real response to the imperative stimulus, which was either congruent or incongruent with the precue information. Experiment 1 provided first evidence favoring our alternative hypothesis that imagery-primed responses should result in larger response priming effects than prepared-responses, suggesting that MI might involve more richly informative motor plans than preparation for action alone. In experiment 2, we manipulated interstimulus foreperiods and replicated the MI-priming effect, showing it to be independent of differences in temporal uncertainty between MI and MP. Experiment 3 showed the MI-priming effect is present in both foot and finger responses, and Experiment 4 suggested the larger congruency effects in the MI condition could not be explained by differences in cognitive load between MI and MP. These results suggest that a strong FE hypothesis does not hold. Findings are discussed in line with the predictive processing models of action and MI. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Behavioural studies have indicated that response times on complex reaction time tasks are faster ... more Behavioural studies have indicated that response times on complex reaction time tasks are faster if blood glucose concentrations are slightly elevated above normal (Donohoe & Benton, 2000). Such tasks involve several cognitive processing stages but it is not clear which of these stages are speeded after glucose administration. In order to investigate this problem we have used a double blind repeated measures design for the administration of glucose and placebo drinks. Participants performed a Flanker task while EEG was recorded as a physiological measure. More specifically, we used a Flanker task that required participants to respond to either left or right pointing central arrows by pressing a left or a right button, respectively. In addition on each trial there are extra arrows surrounding the central arrow which all either pointed in the same (congruent condition) or opposite (incongruent condition) direction as the central arrow or they were lines without an arrow head (neutral ...

Stroke patients with motor deficits often report daytime sleepiness. While slowing of the EEG dur... more Stroke patients with motor deficits often report daytime sleepiness. While slowing of the EEG during wakefulness has been shown after stroke, it is unknown if and how this is linked to their perception of sleepiness. Using waking EEG and a motor task (associated with mild sleepiness), we examined: 1) differences in the frequency composition and lateralisation of the EEG between stroke patients and controls, and 2) the relationship between the EEG and subjective sleepiness ratings. EEG and Karolinska Sleepiness Scale (KSS) data were collected from 15 right hemispheric stroke patients and 15 matched controls before and after a motor priming task. Frequency analysis was performed on C3 and C4 channels. Prior to the task, the stroke group revealed increased power density below 10 Hz compared to controls for both hemispheres, with more pronounced effects within the lesioned hemisphere. The motor task significantly increased KSS scores in both groups. Increased beta and alpha activity was...

The uses of Virtual reality are constantly evolving, from healthcare treatments to evaluating com... more The uses of Virtual reality are constantly evolving, from healthcare treatments to evaluating commercial products, all of which would benefit from a better understanding of the emotional state of the individual. There is ongoing research into developing specially adapted methods for the recognition of the user’s affect while immersed within Virtual Reality. This paper outlines the approaches attempted and the available methodologies that embed sensors into wearable devices for real-time affect detection. These emerging technologies are introducing innovative ways of studying and interpreting emotion related data produced within immersive experiences

The current practical restraints for facial expression recognition in Virtual Reality (VR) led to... more The current practical restraints for facial expression recognition in Virtual Reality (VR) led to the development of a novel wearable interface called Faceteq. Our team designed a pilot feasibility study to explore the effect of spontaneous facial expressions on eight EMG sensors, incorporated on the Faceteq interface. Thirty-four participants took part in the study where they watched a sequence of video stimuli while self-rating their emotional state. After a specifically designed signal pre-processing, we aimed to classify the responses into three classes (negative, neutral, positive). A C-SVM classifier was cross-validated for each participant, reaching an out-of-sample average accuracy of 82.5%. These preliminary results have encouraged us to enlarge our dataset and incorporate data from different physiological signals to achieve automatic detection of combined arousal and valence states for VR applications.

Frontiers in Human Neuroscience, 2011

Background Flanker Congruency Effect-We observed the typical flanker effect; i.e. responses for i... more Background Flanker Congruency Effect-We observed the typical flanker effect; i.e. responses for incongruent trials were slower than in congruent trials (p < 0.01). Drink Effect-In the first block, RTs were slower in the glucose relative to the placebo session (p=0.03). Flanker congruency effects were not modulated by the Drink type (p>.05). Drink Effect dependent on Drink Order-In the first block, the drink effect was further modulated by the factor drink order (p=0.01). More specifically, RTs in the glucose session were slower than in the placebo session when glucose was given before placebo (p=0.02). However, this was not the case when placebo was before glucose (p=0.56). HHSHH Experiment 1 Arrow Flanker Study-Our findings suggest that glucose may slow RTs when participants are inexperienced with a sensorimotor task (1 st block effects). Once experience is gained this effect vanishes, this is possibly because sensorimotor processing becomes too automatic as S-R association is strengthened over successive trials. Experiment 2 Letter Flanker Study-This experiment aimed to keep S-R association low for the duration of the experiment by using novel stimuli on successive blocks of trials. By doing this we demonstrated that glucose can consistently slow RTs on a sensorimotor task for a prolonged period of time (at least 30 minutes). General Discussion-Together both experiments suggest that when S-R associations are low that glucose can slow RTs. In terms of physiology, an increase in glucose metabolism as a result of glucose drink administration may cause oxidative stress. This can impair Na+/K+ channels in the neural membrane and slow neural conduction velocity, and thereby might slow RTs.

One of the potential explanations for negative compatibility effects (NCE) in subliminal motor pr... more One of the potential explanations for negative compatibility effects (NCE) in subliminal motor priming tasks has been perceptual prime-target interactions. Here, we investigate whether the characteristic tri-phasic LRP pattern associated with the NCE is caused by these prime-target interactions. We found that both the prime-related phase and the critical reversal phase remain present even on trials where the target is omitted, confirming they are elicited by the prime and mask, not by prime-target interactions. We also report that shape and size of the reversal phase are associated with response speed, consistent with a causal role for the reversal for the subsequent response latency. Additionally, we analysed sequential modulation of the NCE by previous conflicting events, even though such conflict is subliminal. In accordance with previous literature, this modulation is small but significant.