Cognitive neuroscience explores the mechanisms of cognition by studying its structural and functi... more Cognitive neuroscience explores the mechanisms of cognition by studying its structural and functional brain correlates. Here, we report the first systematic review that assesses how information from structural and functional neuroimaging methods can be integrated to investigate the brain substrates of cognition. Web of Science and Scopus databases were searched for studies of healthy young adult populations that collected cognitive data, and structural and functional neuroimaging data. Five percent of screened studies met all inclusion criteria. Next, 54% of included studies related cognitive performance to brain structure and function without quantitative analysis of the relationship. Finally, 32% of studies formally integrated structural and functional brain data. Overall, many studies consider either structural or functional neural correlates of cognition, and of those that consider both, they have rarely been integrated. We identified four emergent approaches to the characterisa...
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. Available from: Nelson Trujillo-Barreto
Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on... more Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on clinical pain outcomes and treatment efficacy. Mounting evidence suggests catastrophising is associated with resting-state EEG frontal alpha asymmetry (FAA) patterns reflective of greater relative right frontal activity, thought to underly withdrawal motivation and negative affect. Notwithstanding, knowledge on the neurophysiological basis of catastrophising remains limited. The present study aims to investigate whether such relationship occurs in the situational context of experimental pain, and how FAA is modulated by pain and placebo treatment. 35 participants completed the Pain Catastrophising Scale (PCS) questionnaire prior to EEG recordings during cold pressor test (CPT)-induced tonic pain with or without prior application of placebo cream. There was a negative correlation between FAA and PCS-subscale helplessness scores, but not rumination or magnification, during the pre-placebo...
The relationship between structural and functional brain networks has been characterised as compl... more The relationship between structural and functional brain networks has been characterised as complex: the two networks mirror each other and show mutual influence but they also diverge in their organisation. This work explored whether a combination of structural and functional connectivity can improve predictive models of cognitive performance. Principal Component Analysis (PCA) was first applied to cognitive data from the Human Connectome Project to identify components reflecting five cognitive domains: Executive Function, Self-regulation, Language, Encoding and Sequence Processing. A Principal Component Regression (PCR) approach was then used to fit predictive models of each cognitive domain based on structural (SC), functional (FC) or combined structural-functional (CC) connectivity. Self-regulation, Encoding and Sequence Processing were best modelled by FC, whereas Executive Function and Language were best modelled by CC. The present study demonstrates that integrating structural...
ObjectiveAlpha-neurofeedback (α-NFB) is a novel therapy which trains individuals to volitionally ... more ObjectiveAlpha-neurofeedback (α-NFB) is a novel therapy which trains individuals to volitionally increase their alpha power to improve pain. Learning during NFB is commonly measured using static parameters such as mean alpha power. Considering the biphasic nature of alpha rhythm (high and low alpha), dynamic parameters describing the time spent by individuals in high alpha state and the pattern of transitioning between states might be more useful. Here, we quantify the changes during α-NFB for chronic pain in terms of dynamic changes in alpha states.MethodsFour chronic pain and four healthy participants received five NFB sessions designed to increase frontal alpha power. Changes in pain resilience were measured using visual analogue scale (VAS) during repeated cold-pressor tests (CPT). Changes in alpha state static and dynamic parameters such as fractional occupancy (time in high alpha state), dwell time (length of high alpha state) and transition probability (probability of moving ...
One-third of the population in the UK and worldwide struggle with chronic pain. Entraining brain ... more One-third of the population in the UK and worldwide struggle with chronic pain. Entraining brain alpha activity through non-invasive visual stimulation has been shown to reduce experimental pain in healthy volunteers. Neural oscillations entrainment offers a potential non-invasive and non-pharmacological intervention for patients with chronic pain, which can be delivered in the home setting and has the potential to reduce use of medications. However, evidence supporting its use in patients with chronic pain is lacking. This study explores whether a) alpha entrainment increase alpha power in patients and b) whether this increase in alpha correlates with analgesia.28 patients with chronic pain sat in a comfortable position and underwent 4-minute visual stimulation using customised goggles at 10 Hz (alpha) and 7 Hz (control) frequency blocks in a randomised cross-over design. 64-channel Electroencephalography (EEG) and 11-point Numeric Rating Scale (NRS) pain intensity and pain unpleas...
Entraining alpha activity with rhythmic visual, auditory, and electrical stimulation can reduce e... more Entraining alpha activity with rhythmic visual, auditory, and electrical stimulation can reduce experimentally induced pain. However, evidence for alpha entrainment and pain reduction in patients with chronic pain is limited. This feasibility study investigated whether visual alpha stimulation can increase alpha power in patients with chronic musculoskeletal pain and secondarily, if chronic pain was reduced following stimulation. In a within-subject design, 22 patients underwent 4-minute periods of stimulation at 10 Hz (alpha), 7 Hz (high-theta, control), and 1 Hz (control) in a pseudo-randomized order. Patients underwent stimulation both sitting and standing and verbally rated their pain before and after each stimulation block on a 0-10 numerical rating scale. Global alpha power was significantly higher during 10 Hz compared to 1 Hz stimulation when patients were standing (t = −6.08, p
There has been an increasing interest in examining organisational principles of the cerebral cort... more There has been an increasing interest in examining organisational principles of the cerebral cortex (and subcortical regions) using different MRI features such as structural or functional connectivity. Despite the widespread interest, however, an introductory and intuitive review on the underlying technique for the neuroimaging community is lacking in the literature.Articles that investigate “neural gradients” have increased in popularity. Thus, we believe that it is opportune to discuss what is generally meant by “gradient analysis”. We introduce basics concepts in graph theory, such as graphs themselves, the degree matrix, and the adjacency matrix. We discuss how one can think about gradients of feature similarity using graph theory and we extend this to explore such gradients across the whole MRI scale; from the voxel level to the whole brain level. We proceed to introduce a measure for quantifying the level of similarity in regions of interest. We propose the term “the Vogt-Bail...
Introduccion. La enfermedad cerebrovascular causa alteraciones cognitivas disimiles. Es preciso d... more Introduccion. La enfermedad cerebrovascular causa alteraciones cognitivas disimiles. Es preciso desarrollar herramientas capaces de diagnosticarlas, y una de ellas podria ser los potenciales relacionados con eventos. Estos brindan un indicador en tiempo real del procesamiento cognitivo. Pacientes y metodos. Se estudiaron 10 pacientes con infarto cerebral en la region frontal y 10 controles sanos pareados. La evaluacion de los pacientes se realizo una semana despues de presentar el infarto. A ambos grupos se les aplico un test de ejecucion continua asociado al registro de la actividad electrica cerebral para la obtencion del componente P300. Los resultados obtenidos se sometieron a la prueba no parametrica t de Student, y el electroencefalograma, al metodo de promediacion de modelos bayesianos (MPMB) para el calculo de las fuentes generadoras de la actividad electrica registrada. Resultados. Los pacientes tuvieron ejecuciones significativamente mas pobres que los controles sanos en la prueba de atencion. El MPMB mostro que el componente P300 se relaciona con las estructuras temporales derechas en los controles sanos, mientras que en los pacientes se suman las zonas temporoparietales izquierdas. Conclusiones. Estos resultados indican la existencia de alteraciones subclinicas de la atencion sostenida, y que solo herramientas mas sensibles pueden detectarlas; ademas, tienen implicaciones para los circuitos cerebrales reguladores de la atencion sostenida y del componente P300
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2017
Frequency-dependent plasticity (FDP) describes adaptation at the synapse in response to stimulati... more Frequency-dependent plasticity (FDP) describes adaptation at the synapse in response to stimulation at different frequencies. Its consequence on the structure and function of cortical networks is unknown. We tested whether cortical "resonance," favorable stimulation frequencies at which the sensory cortices respond maximally, influenced the impact of FDP on perception, functional topography, and connectivity of the primary somatosensory cortex using psychophysics and functional imaging (fMRI). We costimulated two digits on the hand synchronously at, above, or below the resonance frequency of the somatosensory cortex, and tested subjects' accuracy and speed on tactile localization before and after costimulation. More errors and slower response times followed costimulation at above- or below-resonance, respectively. Response times were faster after at-resonance costimulation. In the fMRI, the cortical representations of the two digits costimulated above-resonance shifted...
We analyze the functional significance of different event-related potentials (ERPs) as electrophy... more We analyze the functional significance of different event-related potentials (ERPs) as electrophysiological indices of face perception and face recognition, according to cognitive and neurofunctional models of face processing. Initially, the processing of faces seems to be supported by early extrastriate occipital cortices and revealed by modulations of the occipital P1. This early response is thought to reflect the detection of certain primary structural aspects indicating the presencegrosso modoof a face within the visual field. The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification. In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM). New ...
This article summarizes the theoretical foundations of Bayesian model inference as regards model ... more This article summarizes the theoretical foundations of Bayesian model inference as regards model selection and model averaging. Although not formally treated here, model combination is also motivated as a variant of Bayesian model averaging. The main practical implementations and approximations to model inference are reviewed, and the relationships among the different approaches are highlighted.
Cerebrovascular disease causes different cognitive alterations. There is a need to develop tools ... more Cerebrovascular disease causes different cognitive alterations. There is a need to develop tools that are capable of diagnosing them. One of them could be event related potentials. These provide an indicator of cognitive processing in real time. A study was conducted of 10 patients with cerebral infarction in the frontal region and 10 paired healthy controls. Evaluation of the patients was performed a week after the stroke. A continuous performance test was applied to both groups together with the recording of the electrical activity in the brain in order to obtain the P300 component. The results were submitted to the non-parametric Student's t test, and the Bayesian model averaging method (BMAM) was employed to calculate the sources generating the electrical activity recorded on the electroencephalogram. Patients displayed significantly poorer performances compared to the healthy controls in the attention test. The BMAM showed that the P300 component was related to the right ha...
Recibido: 12 de diciembre del 2002 Aceptado: 16 de diciembre del 2002 7 recuperando las fuentes c... more Recibido: 12 de diciembre del 2002 Aceptado: 16 de diciembre del 2002 7 recuperando las fuentes corticales con mayor amplitud y menos desparramadas. A la vez, mostro menor cantidad de fuentes fantasmas. ABSTRACT: The Brain Electric Tomography (BET) is a neuroimaging technique able to show the suitable temporal resolution for studying dynamical processes in the brain. It is achieved by solving the Electroencephalography inverse problem (IP), which is an ill-posed problem. There are several inverse solutions according to the a priori assumptions on the solution. They coincide in assuming the same spatial smoothness of solution in all the brain. In this work we proposed the use of Bayesian approach for modeling the IP and finding a Variable Resolution Electromagnetic Tomography (VARETA) type inverse solution. This inverse solution differs from the others in estimating the spatial resolution instead of choosing a fixed one. This was possible thanks to Bayesian inference. VARETA was compared with the traditional method LORETA by using simulated data. It was found that the former recovers cortical sources with higher amplitude and less blurring. It also shows less spurious or ghost sources. INTRODUCCION
Cognitive neuroscience explores the mechanisms of cognition by studying its structural and functi... more Cognitive neuroscience explores the mechanisms of cognition by studying its structural and functional brain correlates. Here, we report the first systematic review that assesses how information from structural and functional neuroimaging methods can be integrated to investigate the brain substrates of cognition. Web of Science and Scopus databases were searched for studies of healthy young adult populations that collected cognitive data, and structural and functional neuroimaging data. Five percent of screened studies met all inclusion criteria. Next, 54% of included studies related cognitive performance to brain structure and function without quantitative analysis of the relationship. Finally, 32% of studies formally integrated structural and functional brain data. Overall, many studies consider either structural or functional neural correlates of cognition, and of those that consider both, they have rarely been integrated. We identified four emergent approaches to the characterisa...
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately. Available from: Nelson Trujillo-Barreto
Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on... more Pain-related catastrophising is a maladaptive coping strategy known to have a strong influence on clinical pain outcomes and treatment efficacy. Mounting evidence suggests catastrophising is associated with resting-state EEG frontal alpha asymmetry (FAA) patterns reflective of greater relative right frontal activity, thought to underly withdrawal motivation and negative affect. Notwithstanding, knowledge on the neurophysiological basis of catastrophising remains limited. The present study aims to investigate whether such relationship occurs in the situational context of experimental pain, and how FAA is modulated by pain and placebo treatment. 35 participants completed the Pain Catastrophising Scale (PCS) questionnaire prior to EEG recordings during cold pressor test (CPT)-induced tonic pain with or without prior application of placebo cream. There was a negative correlation between FAA and PCS-subscale helplessness scores, but not rumination or magnification, during the pre-placebo...
The relationship between structural and functional brain networks has been characterised as compl... more The relationship between structural and functional brain networks has been characterised as complex: the two networks mirror each other and show mutual influence but they also diverge in their organisation. This work explored whether a combination of structural and functional connectivity can improve predictive models of cognitive performance. Principal Component Analysis (PCA) was first applied to cognitive data from the Human Connectome Project to identify components reflecting five cognitive domains: Executive Function, Self-regulation, Language, Encoding and Sequence Processing. A Principal Component Regression (PCR) approach was then used to fit predictive models of each cognitive domain based on structural (SC), functional (FC) or combined structural-functional (CC) connectivity. Self-regulation, Encoding and Sequence Processing were best modelled by FC, whereas Executive Function and Language were best modelled by CC. The present study demonstrates that integrating structural...
ObjectiveAlpha-neurofeedback (α-NFB) is a novel therapy which trains individuals to volitionally ... more ObjectiveAlpha-neurofeedback (α-NFB) is a novel therapy which trains individuals to volitionally increase their alpha power to improve pain. Learning during NFB is commonly measured using static parameters such as mean alpha power. Considering the biphasic nature of alpha rhythm (high and low alpha), dynamic parameters describing the time spent by individuals in high alpha state and the pattern of transitioning between states might be more useful. Here, we quantify the changes during α-NFB for chronic pain in terms of dynamic changes in alpha states.MethodsFour chronic pain and four healthy participants received five NFB sessions designed to increase frontal alpha power. Changes in pain resilience were measured using visual analogue scale (VAS) during repeated cold-pressor tests (CPT). Changes in alpha state static and dynamic parameters such as fractional occupancy (time in high alpha state), dwell time (length of high alpha state) and transition probability (probability of moving ...
One-third of the population in the UK and worldwide struggle with chronic pain. Entraining brain ... more One-third of the population in the UK and worldwide struggle with chronic pain. Entraining brain alpha activity through non-invasive visual stimulation has been shown to reduce experimental pain in healthy volunteers. Neural oscillations entrainment offers a potential non-invasive and non-pharmacological intervention for patients with chronic pain, which can be delivered in the home setting and has the potential to reduce use of medications. However, evidence supporting its use in patients with chronic pain is lacking. This study explores whether a) alpha entrainment increase alpha power in patients and b) whether this increase in alpha correlates with analgesia.28 patients with chronic pain sat in a comfortable position and underwent 4-minute visual stimulation using customised goggles at 10 Hz (alpha) and 7 Hz (control) frequency blocks in a randomised cross-over design. 64-channel Electroencephalography (EEG) and 11-point Numeric Rating Scale (NRS) pain intensity and pain unpleas...
Entraining alpha activity with rhythmic visual, auditory, and electrical stimulation can reduce e... more Entraining alpha activity with rhythmic visual, auditory, and electrical stimulation can reduce experimentally induced pain. However, evidence for alpha entrainment and pain reduction in patients with chronic pain is limited. This feasibility study investigated whether visual alpha stimulation can increase alpha power in patients with chronic musculoskeletal pain and secondarily, if chronic pain was reduced following stimulation. In a within-subject design, 22 patients underwent 4-minute periods of stimulation at 10 Hz (alpha), 7 Hz (high-theta, control), and 1 Hz (control) in a pseudo-randomized order. Patients underwent stimulation both sitting and standing and verbally rated their pain before and after each stimulation block on a 0-10 numerical rating scale. Global alpha power was significantly higher during 10 Hz compared to 1 Hz stimulation when patients were standing (t = −6.08, p
There has been an increasing interest in examining organisational principles of the cerebral cort... more There has been an increasing interest in examining organisational principles of the cerebral cortex (and subcortical regions) using different MRI features such as structural or functional connectivity. Despite the widespread interest, however, an introductory and intuitive review on the underlying technique for the neuroimaging community is lacking in the literature.Articles that investigate “neural gradients” have increased in popularity. Thus, we believe that it is opportune to discuss what is generally meant by “gradient analysis”. We introduce basics concepts in graph theory, such as graphs themselves, the degree matrix, and the adjacency matrix. We discuss how one can think about gradients of feature similarity using graph theory and we extend this to explore such gradients across the whole MRI scale; from the voxel level to the whole brain level. We proceed to introduce a measure for quantifying the level of similarity in regions of interest. We propose the term “the Vogt-Bail...
Introduccion. La enfermedad cerebrovascular causa alteraciones cognitivas disimiles. Es preciso d... more Introduccion. La enfermedad cerebrovascular causa alteraciones cognitivas disimiles. Es preciso desarrollar herramientas capaces de diagnosticarlas, y una de ellas podria ser los potenciales relacionados con eventos. Estos brindan un indicador en tiempo real del procesamiento cognitivo. Pacientes y metodos. Se estudiaron 10 pacientes con infarto cerebral en la region frontal y 10 controles sanos pareados. La evaluacion de los pacientes se realizo una semana despues de presentar el infarto. A ambos grupos se les aplico un test de ejecucion continua asociado al registro de la actividad electrica cerebral para la obtencion del componente P300. Los resultados obtenidos se sometieron a la prueba no parametrica t de Student, y el electroencefalograma, al metodo de promediacion de modelos bayesianos (MPMB) para el calculo de las fuentes generadoras de la actividad electrica registrada. Resultados. Los pacientes tuvieron ejecuciones significativamente mas pobres que los controles sanos en la prueba de atencion. El MPMB mostro que el componente P300 se relaciona con las estructuras temporales derechas en los controles sanos, mientras que en los pacientes se suman las zonas temporoparietales izquierdas. Conclusiones. Estos resultados indican la existencia de alteraciones subclinicas de la atencion sostenida, y que solo herramientas mas sensibles pueden detectarlas; ademas, tienen implicaciones para los circuitos cerebrales reguladores de la atencion sostenida y del componente P300
Proceedings of the National Academy of Sciences of the United States of America, Jan 15, 2017
Frequency-dependent plasticity (FDP) describes adaptation at the synapse in response to stimulati... more Frequency-dependent plasticity (FDP) describes adaptation at the synapse in response to stimulation at different frequencies. Its consequence on the structure and function of cortical networks is unknown. We tested whether cortical "resonance," favorable stimulation frequencies at which the sensory cortices respond maximally, influenced the impact of FDP on perception, functional topography, and connectivity of the primary somatosensory cortex using psychophysics and functional imaging (fMRI). We costimulated two digits on the hand synchronously at, above, or below the resonance frequency of the somatosensory cortex, and tested subjects' accuracy and speed on tactile localization before and after costimulation. More errors and slower response times followed costimulation at above- or below-resonance, respectively. Response times were faster after at-resonance costimulation. In the fMRI, the cortical representations of the two digits costimulated above-resonance shifted...
We analyze the functional significance of different event-related potentials (ERPs) as electrophy... more We analyze the functional significance of different event-related potentials (ERPs) as electrophysiological indices of face perception and face recognition, according to cognitive and neurofunctional models of face processing. Initially, the processing of faces seems to be supported by early extrastriate occipital cortices and revealed by modulations of the occipital P1. This early response is thought to reflect the detection of certain primary structural aspects indicating the presencegrosso modoof a face within the visual field. The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification. In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM). New ...
This article summarizes the theoretical foundations of Bayesian model inference as regards model ... more This article summarizes the theoretical foundations of Bayesian model inference as regards model selection and model averaging. Although not formally treated here, model combination is also motivated as a variant of Bayesian model averaging. The main practical implementations and approximations to model inference are reviewed, and the relationships among the different approaches are highlighted.
Cerebrovascular disease causes different cognitive alterations. There is a need to develop tools ... more Cerebrovascular disease causes different cognitive alterations. There is a need to develop tools that are capable of diagnosing them. One of them could be event related potentials. These provide an indicator of cognitive processing in real time. A study was conducted of 10 patients with cerebral infarction in the frontal region and 10 paired healthy controls. Evaluation of the patients was performed a week after the stroke. A continuous performance test was applied to both groups together with the recording of the electrical activity in the brain in order to obtain the P300 component. The results were submitted to the non-parametric Student's t test, and the Bayesian model averaging method (BMAM) was employed to calculate the sources generating the electrical activity recorded on the electroencephalogram. Patients displayed significantly poorer performances compared to the healthy controls in the attention test. The BMAM showed that the P300 component was related to the right ha...
Recibido: 12 de diciembre del 2002 Aceptado: 16 de diciembre del 2002 7 recuperando las fuentes c... more Recibido: 12 de diciembre del 2002 Aceptado: 16 de diciembre del 2002 7 recuperando las fuentes corticales con mayor amplitud y menos desparramadas. A la vez, mostro menor cantidad de fuentes fantasmas. ABSTRACT: The Brain Electric Tomography (BET) is a neuroimaging technique able to show the suitable temporal resolution for studying dynamical processes in the brain. It is achieved by solving the Electroencephalography inverse problem (IP), which is an ill-posed problem. There are several inverse solutions according to the a priori assumptions on the solution. They coincide in assuming the same spatial smoothness of solution in all the brain. In this work we proposed the use of Bayesian approach for modeling the IP and finding a Variable Resolution Electromagnetic Tomography (VARETA) type inverse solution. This inverse solution differs from the others in estimating the spatial resolution instead of choosing a fixed one. This was possible thanks to Bayesian inference. VARETA was compared with the traditional method LORETA by using simulated data. It was found that the former recovers cortical sources with higher amplitude and less blurring. It also shows less spurious or ghost sources. INTRODUCCION
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