Examinando por Autor "Mercado, Francisco"

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Cortical response to subjectively unconscious danger
(Neuroimage, 2005) Carretié, Luis; Hinojosa, José Antonio; Mercado, Francisco; Tapia, Manuel
Cortical involvement in the evolution-favored automatic reaction to danger was studied. Electrical neural activity was recorded from 31 subjects, reporting fear of spiders, at 60 scalp locations. Visual stimuli containing spiders (negative elements) or, alternatively, nonnegative elements were presented to subjects, though they were unaware of their presence: a concurrent visual detection task using consciously perceived targets was administered. Spatial and temporal principal component analyses were employed to define and quantify, in a reliable manner, the main components of the neuroelectrical response to unconscious stimuli, and a source localization algorithm provided information on their neural origin. Results indicated that around 150 ms after stimulus onset,ventromedial prefrontal areas previously reported as responding rapidly to danger-related (conscious) stimuli were activated by unconsciously perceived spiders more markedly than by nonnegative unconscious stimuli. Subsequently, around 500 ms after stimulus onset, activation of the posterior cingulate and visual association cortices increased in this same direction. These data support previous results indicating that the ventromedial prefrontal cortex is involved in the topdown regulation of attention (through its capability to modulate the activity of posterior cortices in charge of visual processing) and that it automatically facilitates danger processing.
Decreased Pain Perception by Unconscious Emotional Pictures
(Frontiers Media, 2016-10-21) Peláez, Irene; Martínez-Íñigo, David; Barjola, Paloma; Cardoso, Susana; Mercado, Francisco
La percepción del dolor surge de una interacción compleja entre un estímulo nociceptivo y diversos factores emocionales y cognitivos, los cuales parecen estar mediados por sistemas tanto automáticos como controlados. Evidencia previa ha demostrado que, mientras el procesamiento consciente de estímulos desagradables intensifica la percepción del dolor, se sabe mucho menos sobre las influencias emocionales en el dolor bajo condiciones no conscientes. El objetivo del presente estudio fue investigar la modulación de la percepción del dolor mediante imágenes emocionales no conscientes a través de un paradigma de enmascaramiento emocional. Se emplearon dos tipos de estimulación, tanto somatosensorial (dolorosa y no dolorosa) como emocional (imágenes negativas y neutrales). Cincuenta participantes sin dolor fueron instruidos para calificar la percepción del dolor que sentían en respuesta a estímulos somatosensoriales inducidos por láser lo más rápido posible. Se midieron los datos de intensidad del dolor y los tiempos de reacción. Los análisis estadísticos revelaron un efecto significativo en la interacción entre el dolor y la estimulación emocional, aunque sorprendentemente esta relación fue opuesta a la esperada. En particular, se encontraron puntuaciones de menor intensidad del dolor y tiempos de reacción más largos en respuesta a imágenes negativas, con un efecto aún más pronunciado en la estimulación dolorosa. Estos hallazgos sugieren una clara modulación de la percepción del dolor por contextos emocionales no conscientes. Mecanismos de captura atencional desencadenados por la estimulación negativa no consciente podrían explicar este fenómeno, al provocar un retiro de los recursos de procesamiento del dolor.
Effects of COMT Genotypes on Working Memory Performance in Fibromyalgia Patients
(MDPI, 2020-08-01) Ferrera, David; Gómez-Esquer, Francisco; Peláez, Irene; Barjola, Paloma; Fernandes-Magalhaes, Roberto; Carpio, Alberto; De Lahoz, María Eugenia; Díaz-Gil, Gema; Mercado, Francisco
Growing research has reported the presence of a clear impairment of working memory functioning in fibromyalgia. Although different genetic factors involving dopamine availability (i.e, the COMT gene) have been associated with the more severe presentation of key symptoms in fibromyalgia, scientific evidence regarding the influence of COMT genotypes on cognitive impairment in these patients is still lacking. To this end, 167 participants took part in the present investigation. Working memory performance was assessed by the application of the SST (Spatial Span Test) and LNST (Letter and Number Sequence Test) belonging to the Weschler Memory Scale III. Significant working memory impairment was shown by the fibromyalgia patients. Remarkably, our results suggest that performance according to different working memory measures might be influenced by different genotypes of the COMT gene. Specifically, fibromyalgia patients carrying the Val/Val genotype exhibited significantly worse outcomes for the span of SST backward, SST backward score, SST total score and the Working Memory Index (WMI) than the Val/Val healthy carriers. Furthermore, the Val/Val patients performed worse on the SST backward and SST score than heterozygotes. Our findings are the first to show a link between the COMT gene and working memory dysfunction in fibromyalgia, supporting the idea that higher COMT enzyme activity would contribute to more severe working memory impairment in fibromyalgia.
Electrophysiological indices of pain expectation abnormalities in fibromyalgia patients
(Frontiers in Human Neuroscience, 2022-09-30) Barjola , Paloma; Peláez, Irene; Ferrera, David; González-Gutiérrez, José Luis; Velasco, Lilian; Peñacoba-Puente, Cecilia; López-López, Almudena; Fernandes-Magalhaes, Roberto; Mercado, Francisco
Fibromyalgia is a chronic pain syndrome characterized by dysfunctional processing of nociceptive stimulation. Neuroimaging studies have pointed out that pain-related network functioning seems to be altered in these patients. It is thought that this clinical symptomatology may be maintained or even strengthened because of an enhanced expectancy for painful stimuli or its forthcoming appearance. However, neural electrophysiological correlates associated with such attentional mechanisms have been scarcely explored. In the current study, expectancy processes of upcoming laser stimulation (painful and non-painful) and its further processing were explored by event-related potentials (ERPs). Nineteen fibromyalgia patients and twenty healthy control volunteers took part in the experiment. Behavioral measures (reaction times and subjective pain perception) were also collected. We manipulated the pain/no pain expectancy through an S1–S2 paradigm (cue-target). S1 (image: triangle or square) predicted the S2 appearance (laser stimulation: warmth or pinprick sensation). Laser stimuli were delivered using a CO2 laser device. Temporal and spatial principal component analyses were employed to define and quantify the ERP component reliability. Statistical analyses revealed the existence of an abnormal pattern of pain expectancy in patients with fibromyalgia. Specifically, our results showed attenuated amplitudes at posterior lCNV component in anticipation of painful stimulation that was not found in healthy participants. In contrast, although larger P2 amplitudes to painful compared to innocuous events were shown, patients did not show any amplitude change in this laser-evoked response as a function of pain predictive cues (as occurred in the healthy control group). Additionally, analyses of the subjective perception of pain and reaction time indicated that laser stimuli preceded by pain cues were rated as more painful than those signaling non-pain expectancy and were associated with faster responses. Differences between groups were not found. The present findings suggest the presence of dysfunction in pain expectation mechanisms in fibromyalgia that eventually may make it difficult for patients to correctly interpret signs that prevent pain symptoms. Furthermore, the abnormal pattern in pain expectancy displayed by fibromyalgia patients could result in ineffective pain coping strategies. Understanding the neural correlates of pain processing and its modulatory factors is crucial to identify treatments for chronic pain syndromes.
Fear of pain moderates the relationship between self-reported fatigue and methionine allele of catechol-O-methyltransferase gene in patients with fibromyalgia
(Public Library of Science, 2021-04-28) Ferrera, David; Mercado, Francisco; Peláez, Irene; Martínez-Íñigo, David; Fernandes-Magalhaes, Roberto; Barjola, Paloma; Écija, Carmen; Díaz-Gil, Gema; Gómez-Esquer, Francisco
Previous research has shown a consistent association among genetic factors, psychological symptoms and pain associated with fibromyalgia. However, how these symptoms interact to moderate genetic factors in fibromyalgia has rarely been studied to date. The present research investigates whether psychological symptoms can moderate the effects of catechol-O-methyltransferase on pain and fatigue. A total of 108 women diagnosed with fibromyalgia and 77 healthy control participants took part in the study. Pain, fatigue, and psychological symptoms (anxiety, depression, pain catastrophizing, fear of pain and fear of movement) were measured by self-report questionnaires. Two types of statistical analyses were performed; the first was undertaken to explore the influences of COMT genotypes on clinical symptoms by comparing patients with fibromyalgia and healthy controls. In the second analysis, moderation analyses to explore the role of psychological symptoms as potential factors that moderate the relationship between pain/fatigue and COMT genotypes were performed. The main results indicated that patients carrying the Met/Met genotype reported significantly higher levels of fatigue than heterozygote carriers (i.e., Met/Val genotype) and higher levels of fatigue, but not significantly different, than Val homozygote carriers. Among patients with fibromyalgia carrying methionine alleles (i.e., Met/Met + Met/Val carriers), only those who scored high on medical fear of pain, experienced an intensified feeling of fatigue. Thus, the present research suggests that fear of pain, as a psychological symptom frequently described in fibromyalgia may act as a moderating factor in the relationship between the Met allele of the COMT gene and the increase or decrease in self-reported fatigue. Although further research with wider patient samples is needed to confirm the present findings, these results point out that the use of psychological interventions focused on affective symptomatology might be a useful tool to reduce the severity of fibromyalgia.
Incidental encoding of emotional pictures: Affective bias studied through
(International journal of psychophysiology, 2008) Tapia, Manuel; Carretié, Luis; Sierra, Benjamín; Mercado, Francisco
Emotional stimuli are better remembered than neutral stimuli. Most of the studies taking into account this emotional bias refer to explicit memory, use behavioral measures of the recall and predict better recall of negative stimuli. The few studies taking into account implicit memory and the valence emotional dimension are inconclusive on the effect of the stimulus' emotional valence. In the present study, 120 pictures (30 positive, 30 negative, 30 relaxing and 30 neutral) were shown to, and assessed by, 28 participants (study phase). Subsequently, event related brain potentials (ERPs) were recorded during the presentation of 120 new (shown for the first time) and 120 old (already shown in the study phase)pictures (test phase). No explicit instructions or clues related to recovery were given to participants, and a distractor task was employed, in order to maintain implicit the memory assessment. As expected from other studies' data, our results showed that old stimuli elicited an enhanced late positive component 450 ms after stimulus onset (repetition effect). Moreover, this effect was modulated by the stimuli's emotional valence, since the most positively valenced stimuli were associated with a decreased repetition effect with respect to the most negatively valenced stimuli. This effect was located at ventromedial prefrontal cortex. These results suggest the existence of a valence-mediated bias in implicit memory.
Neural activity associated with metaphor comprehension: spatial analysis
(Neuroscience Letters, 2005) Sotillo, María; Carretié, Luis; Hinojosa, José Antonio; Tapia, Manuel; Mercado, Francisco; López, Sara; Albert, Jacobo
Though neuropsychological data indicate that the right hemisphere (RH) plays a major role in metaphor processing, other studies suggest that, at least during some phases of this processing, a RHadvantage may not exist. The present study explores, through a temporally agile neural signal¿the event-related potentials (ERPs)¿, and through source-localization algorithms applied to ERP recordings, whether the crucial phase of metaphor comprehension presents or not a RH advantage. Participants (n = 24) were submitted to a S1¿S2 experimental paradigm. S1 consisted of visually presented metaphoric sentences (e.g., ¿Green lung of the city¿), followed by S2, which consisted of words that could (i.e., ¿Park¿) or could not (i.e., ¿Semaphore¿) be defined by S1. ERPs elicited by S2 were analyzed using temporal principal component analysis (tPCA) and source-localization algorithms. These analyses revealed that metaphorically related S2 words showed significantly higher N400 amplitudes than non-related S2 words. Source-localization algorithms showed differential activity between the two S2 conditions in the right middle/superior temporal areas. These results support the existence of an important RH contribution to (at least) one phase of metaphor processing and, furthermore, implicate the temporal cortex with respect to that contribution.
Neural correlates of an early attentional capture by positive distractor words
(Frontiers in Psychology, 2015) Hinojosa, José Antonio; Mercado, Francisco; Albert, Jacobo; Barjola, Paloma; Peláez, Irene; Villalba-García, Cristina; Carretié, Luis
La atención exógena o automática a distractores emocionales se ha observado en escenas y rostros emocionales. Sin embargo, en el ámbito del lenguaje, la captura automática de la atención por palabras emocionales ha sido poco investigada. En el presente estudio de potenciales relacionados con eventos, exploramos los efectos de los distractores provocados por palabras positivas, negativas y neutrales en un paradigma de distractores y objetivos concurrentes pero distintos. Específicamente, los participantes realizaron una tarea de categorización de dígitos en la que palabras irrelevantes para la tarea estaban flanqueadas por números. Los resultados de los análisis de componentes principales temporoespaciales y de localización de fuentes revelaron la existencia de efectos tempranos de los distractores, desencadenados específicamente por palabras positivas. A nivel del cuero cabelludo, las palabras distractoras positivas, en comparación con las neutrales y negativas, provocaron amplitudes más grandes en un componente negativo anterior que alcanzó su punto máximo alrededor de los 120 ms. Además, a nivel de vóxel, las palabras distractoras positivas aumentaron la actividad en regiones orbitofrontales en comparación con las palabras negativas. Estos resultados sugieren que las palabras distractoras positivas capturan rápida y automáticamente los recursos atencionales, desviándolos de la tarea en la que la atención estaba dirigida voluntariamente.
Neural correlates of the attentional bias towards pain-related faces in fibromyalgia patients: An ERP study using a dot-probe task
(Elsevier, 2021) Fernandes-Magalhaes, Roberto; Ferrera, David; Peláez, Irene; Martín-Buro, María Carmen; Carpio, Alberto; Lahoz, María Eugenia de; Barjola, Paloma; Mercado, Francisco
Background One of the major cognitive deficits in fibromyalgia has been linked to the hypervigilance phenomenon. It is mainly reflected as a negative bias for allocating attentional resources towards both threatening and pain-related information. Although the interest in its study has recently grown, the neural temporal dynamics of the attentional bias in fibromyalgia still remains an open question. Method Fifty participants (25 fibromyalgia patients and 25 healthy control subjects) performed a dot-probe task. Two types of facial expressions (pain-related and neutral) were employed as signal stimuli. Then, as a target stimulus, a single dot replaced the location of one of these two faces. Event-related potentials (ERP) in response to facial expressions and target stimulation (i.e., dot) were recorded. Reaction time (RT) and accuracy measures in the experimental task were collected as behavioural outcomes. Results Temporal dynamics of brain electrical activity were analysed on two ERP components (P2 and N2a) sensitive to the facial expressions meaning. Pain-related faces elicited higher frontal P2 amplitudes than neutral faces for the whole sample. Interestingly, an interaction effect between group and facial expressions was also found showing that pain-related faces elicited enhanced P2 amplitudes (at fronto-central regions, in this case) compared to neutral faces only when the group of patients was considered. Furthermore, higher P2 amplitudes were observed in response to pain-related faces in patients with fibromyalgia compared to healthy control participants. Additionally, a shorter latency of P2 (at centro-parietal regions) was also detected for pain-related facial expressions compared to neutral faces. Regarding the amplitude of N2a, it was lower for patients as compared to the control group. Non-relevant effects of the target stimulation on the ERPs were found. However, patients with fibromyalgia exhibited slower RT to locate the single dot for incongruent trials as compared to congruent and neutral trials. Conclusions Data suggest the presence of an attentional bias in fibromyalgia that it would be followed by a deficit in the allocation of attentional resources to further process pain-related information. Altogether the current results suggest that attentional biases in fibromyalgia might be explained by automatic attentional mechanisms, which seem to be accompanied by an alteration of more strategic or controlled attentional components.
Neural mechanisms underlying attentional bias modification in fibromyalgia patients: a double‑blind ERP study
(Springer, 2023-11-19) Fernandes-Magalhaes, Roberto; Carpio, Alberto; Ferrera, David; Peláez, Irene; De Lahoz, Maria Eugenia; Van Ryckeghem, Dimitri; Van Damme, Stefaan; Mercado, Francisco
There is a growing interest in the potential benefits of attentional bias modification (ABM) training in chronic pain patients. However, studies examining the effectiveness of ABM programs in fibromyalgia patients have demonstrated inconclusive effects on both behavioral indices and clinical symptoms. Additionally, underlying neural dynamics of ABM effects could yield new insights but remain yet unexplored. Current study, therefore, aims to investigate the effects of ABM training on known neural electrophysiological indicators of attentional bias to pain (P2, N2a). Thirty-two fibromyalgia patients were enrolled and randomly assigned to an ABM training (N = 16) or control (N = 16) condition (2 weeks duration). Within the ABM training condition participants performed five sessions consisting of a modified version of the dot-probe task in which patients were trained to avoid facial pain expressions, whereas in the control group participants performed five sessions consisting of a standard version of the dot-probe task. Potential ABM training effects were evaluated by comparing a single pre- and post-treatment session, in which event-related potentials (ERPs) were recorded in response to both facial expressions and target stimuli. Furthermore, patients filled out a series of self-report questionnaires assessing anxiety, depression, pain-related worrying, fear of pain, fatigue and pain status. After training, results indicated an overall reduction of the amplitude of the P2 component followed by an enhancement of N2a amplitude for the ABM condition compared to control condition. In addition, scores on anxiety and depression decreased in patients assigned to the training condition. However, we found no effects derived from the training on pain-related and fatigue status. Present study offers new insights related to the possible neural mechanisms underlying the effect of ABM training in fibromyalgia. Clinical trial (TRN: NCT05905159) retrospectively registered (30/05/2023).
Neural response to sustained affective visual stimulation using an indirect task
(Experimental Brain Research, 2006) Carretié, Luis; Hinojosa, José Antonio; Albert, Jacobo; Mercado, Francisco
Event-related potentials were recorded from 30 subjects using sustained stimulation and an indirect task, two strategies which facilitate affective responses that are complete and free of cognitive interference. Stimuli were of three types: pleasant, unpleasant and neutral. A three-phase pattern was found. The first phase, an amplitude increase in response to negative stimuli higher than to neutral and pleasant stimuli, was produced at 160 ms after stimulus onset, the prefrontal cortex being the origin of this phase. The second phase, characterized by maximal amplitudes in response to positive stimuli, was produced at 400 ms, originating in the visual cortex. Finally, the third phase, another amplitude increase in response to negative stimuli, was produced at 680 ms, and its source was located in the left precentral gyrus. Present data show that the cortical response to sustained emotional visual stimulation presented within indirect tasks provides information on attention-, motivation-and motor-related biases that complement information obtained under other experimental conditions.
Pain E-motion Faces Database (PEMF): Pain-related micro-clips for emotion research
(Springer, 2022) Fernandes-Magalhaes, Roberto; Carpio, Alberto; Ferrera, David; Ryckeghem, Dimitri Van; Peláez, Irene; Barjola, Paloma; Lahoz, María Eugenia De; Martín-Buro, María Carmen; Hinojosa, José Antonio; Damme, Stefaan Van; Carretié, Luis; Mercado, Francisco
A large number of publications have focused on the study of pain expressions. Despite the growing knowledge, the availability of pain-related face databases is still very scarce compared with other emotional facial expressions. The Pain E-Motion Faces Database (PEMF) is a new open-access database currently consisting of 272 micro-clips of 68 diferent identities. Each model displays one neutral expression and three pain-related facial expressions: posed, spontaneous-algometer and spontaneous-CO2 laser. Normative ratings of pain intensity, valence and arousal were provided by students of three diferent European universities. Six independent coders carried out a coding process on the facial stimuli based on the Facial Action Coding System (FACS), in which ratings of intensity of pain, valence and arousal were computed for each type of facial expression. Gender and age efects of models across each type of micro-clip were also analysed. Additionally, participants’ ability to discriminate the veracity of pain-related facial expressions (i.e., spontaneous vs posed) was explored. Finally, a series of ANOVAs were carried out to test the presence of other basic emotions and common facial action unit (AU) patterns. The main results revealed that posed facial expressions received higher ratings of pain intensity, more negative valence and higher arousal compared with spontaneous pain-related and neutral faces. No diferential efects of model gender were found. Participants were unable to accurately discriminate whether a given pain-related face represented spontaneous or posed pain. PEMF thus constitutes a large open-source and reliable set of dynamic pain expressions useful for designing experimental studies focused on pain processes.
Recursos cognitivos de percepción de control, procesos
(Psichotema, 2009) González, José Luis; Peñacoba, Cecilia; Velasco, Lilian; López, Almudena; Mercado, Francisco; Barjola, Paloma
El presente estudio evalúa un modelo estructural de relaciones entre los recursos cognitivos de control percibido sobre la enfermedad (expectativas de autoeficacia y lugar de control interno de dolor), el estado de estrés-recuperación y el malestar afectivo en mujeres con fibromialgia (n= 130). Los resultados fueron consistentes con la propuesta de que el balance de estrés-recuperación media la relación entre los recursos cognitivos y el malestar afectivo. Asimismo, se observó la presencia de un efecto directo por parte de los recursos cognitivos sobre la limitación funcional, mientras que la intensidad de dolor y los otros síntomas de enfermedad fueron directamente predictores del malestar afectivo. Teniendo en cuenta estos resultados, se señala la posible interpretación de una buena parte de las técnicas cognitivo-conductuales utilizadas habitualmente para el tratamiento de la fibromialgia, como herramientas orientadas a la búsqueda del correcto equilibrio entre estrés y recuperación, resultandofundamental para ello la modificación de las creencias de autoeficacia y las expectativas de control.
Subliminal emotional pictures are capable of modulating early cerebral responses to pain in fibromyalgia
(Public Library of Science, 2019-06-05) Peláez, Irene; Ferrera, David; Barjola, Paloma; Fernandes-Magalhaes, Roberto; Mercado, Francisco
Pain experience involves a complex relationship between sensory and both emotional and cognitive factors, which appear to be mediated by different neural pathways. Previous evidence has shown that whereas conscious processing of unpleasant stimuli enhances pain perception, the influence of emotions on pain under unaware conditions is much less known. The need to better characterise the relationship between pain processing and emotional factors is crucial for dealing with chronic pain conditions. Therefore, the present study aimed to explore the neural correlates relating to the influence of visual masking emotional stimulation on the processing of painful stimuli in chronic pain patients suffering from fibromyalgia (FM). Twenty FM and 22 healthy control (HC) women participated in the study. The experimental masking paradigm consisted of a rapid succession of two types of stimuli, where a masked picture (neutral, negative or pain-related) was followed by a laser stimulus (painful or not painful). LEP activity was recorded at sixty scalp electrodes. An LEP-amplitude approach was used to quantify the main cerebral waves linked to pain response. ANOVAs indicated that the posterior regions of the P1 component were sensitive to experimental manipulation (p<0.05). Specifically, FM patients showed higher amplitudes to painful stimuli preceded by pain-related pictures compared with painful trials preceded by other emotional pictures. The FM group also showed greater amplitudes than those in the HC group in P2a and P2b waves. In addition to the scalp data, at the neural level the posterior cingulate cortex, lingual gyrus and insular cortex showed higher activation in the FM group than in the HC group. Our findings show an early cerebral modulation of pain (as reflected by the P1) in FM patients, suggesting that only pain-related information, even when it is unconsciously perceived, is capable to enhance exogenous (automatic) attention, increasing the neural activity involved in processing painful stimulation. Further research is needed to fully understand unconscious emotional influences on pain in fibromyalgia.
The emotional S1-S2 paradigm for exploring brain mechanisms underlying affective modulation of expectancy
(Nova Publishers, 2008) Mercado, Francisco; Hinojosa, José Antonio; Peñacoba, Cecilia; Carretié, Luis
From the past decade to date, research on the interactive brain mechanisms between attention and emotion studied through event-related potentials (ERPs) has increasingly grown. This brain signal reflects fast and swift cognitive processing due to its excellent temporal resolution and it has become a suitable tool in order to study several issues concerning cognitive processing. In this chapter we present a detailed description of an `emotional variant¿ of the S1 (cue)-S2 (target) task that has been typically used to explore vigilance-related attention. The application of the emotional S1-S2 paradigm elicits an affective modulation effect on a brainwave that has been related to expectancy, the early Contingent Negative Variation (eCNV). In this chapter we will present several issues concerning different methodological aspects to take into account when applying this paradigm and some details related to the procedures of quantification and analysis of the ERP data. Finally, some findings obtained through the use of the emotional S1-S2 protocol are summarized and some of its different application possibilities (e.g., clinical samples) are proposed.
The influence of emotional context on attention in anxious subjects: neurophysiological correlates
(Journal of Anxiety Disorders, 2006) Mercado, Francisco; Carretié, Luis; Tapia, Manuel; Gómez-Jarabo, Gregorio
Several studies have shown the influence of threatening context on level of attention to target environmental stimuli. The present experiment explored the possibility that this influence of aversive context is particularly strong in anxious subjects, due to their known attentional bias towards negative information. Event-related potentials, that provide a direct index of attention-related cerebral processing, were recorded in 27 participants selected from a larger sample of 250, as a function of their trait anxiety scores (14 high, 13 low). State anxiety was also measured in selected subjects. Several contexts were presented: positive, negative, relaxing and neutral, and participants were instructed to attend, within these contexts, to a series of auditory stimuli. Threatening context triggered an increase in attention to these auditory stimuli only in conditions of high state anxiety, this increase being reflected in the greater amplitude of the P2 component, which is related to attentional processes. There were no significant differences in relation to trait anxiety. Data show that threatening context and high level of state anxiety in combination increase the quantity of attentional resources directed to the environment.
Two succesive phases in the threat-related attentional response of anxious subjects: neural correlates
(Depression and Anxiety, 2009-12) Mercado, Francisco
Background: It is well known that highly anxious individuals are characterized by the allocation of a greater amount of attentional resources to threatening stimulation. However, neural data in relation to the time course of attentional biases in anxiety are still surprisingly scarce and preliminary. The present research explored attentional biases in anxious subjects (grouped according to their scores in trait and state forms of the State¿Trait Anxiety Inventory) over time by using event-related potentials (ERPs) and through the application of source localization methodologies. Methods: Participants (n527) were asked to perform an indirect visual matching task in a cue-target paradigm. The targets consisted of three types of emotional pictures: positive arousing, negative arousing, and neutral. ERPs in response to target stimulation were submitted to temporal and spatial principal component analyses. Results: Statistical analyses revealed that negative targets elicited higher amplitudes than positive pictures in P200. Subsequently, greater amplitudes in response to positive than to negative pictures were observed in P500. Source analyses (standardized low resolution brain electro-magnetic tomography: sLORETA) indicated an involvement of visual association cortical areas (i.e., precuneus and cuneus) both in P200 and P500. Conclusions: The results might be interpreted in line with the orienting-avoidance hypothesis toward threatening events in anxious subjects. This attentional pattern was only manifested by individuals with high levels of both trait and state anxiety. Further investigation should be done in order to better understand the brain mechanisms underlying the attentional biases in anxiety and to apply this knowledge to the development of cognitive therapies.
Unveiling the Role of Contingent Negative Variation (CNV) in Migraine: A Review of Electrophysiological Studies in Adults and Children
(MDPI, 2023-11-11) De Lahoz , Maria Eugenia; Barjola, Paloma; Peláez, Irene; Ferrera, David; Fernandes-Magalhaes, Roberto; Mercado, Francisco
Migraine has been considered a chronic neuronal-based pain disorder characterized by the presence of cortical hyperexcitability. The Contingent Negative Variation (CNV) is the most explored electrophysiological index in migraine. However, the findings show inconsistencies regarding its functional significance. To address this, we conducted a review in both adults and children with migraine without aura to gain a deeper understanding of it and to derive clinical implications. The literature search was conducted in the PubMed, SCOPUS and PsycINFO databases until September 2022m and 34 articles were retrieved and considered relevant for further analysis. The main results in adults showed higher CNV amplitudes (with no habituation) in migraine patients. Electrophysiological abnormalities, particularly focused on the early CNV subcomponent (eCNV), were especially prominent a few days before the onset of a migraine attack, normalizing during and after the attack. We also explored various modulatory factors, including pharmacological treatments—CNV amplitude was lower after the intake of drugs targeting neural hyperexcitability—and other factors such as psychological, hormonal or genetic/familial influences on CNV. Although similar patterns were found in children, the evidence is particularly scarce and less consistent, likely due to the brain’s maturation process during childhood. As the first review exploring the relationship between CNV and migraine, this study supports the role of the CNV as a potential neural marker for migraine pathophysiology and the prediction of pain attacks. The importance of further exploring the relationship between this neurophysiological index and childhood migraine is critical for identifying potential therapeutic targets for managing migraine symptoms during its development.
Working memory dysfunction in fibromyalgia is associated with genotypes of the catechol- O-methyltransferase gene: an event-related potential study
(Springer, 2022) Ferrera, David; Gómez-Esquer, Francisco; Peláez, Irene; Barjola, Paloma; Fernandes-Magalhaes, Roberto; Carpio, Alberto; Lahoz, María Eugenia De; Martín-Buro, María Carmen; Mercado, Francisco
Recent fndings have associated diferent COMT genotypes with working memory capacity in patients with fbromyalgia. Although it is thought that the COMT gene may infuence neural correlates (P2 and P3 ERP components) underlying working memory impairment in this chronic-pain syndrome, it has not yet been explored. Therefore, the aim of the present research was to investigate the potential efect of the COMT gene in fbromyalgia patients on ERP working memory indices (P2 and P3 components). For this purpose, 102 participants (51 patients and 51 healthy control participants) took part in the experiment. Event-related potentials and behavioral responses were recorded while participants performed a spatial n-back task. Participants had to decide if the stimulus coincided or not in the same location as the one presented one (1-back condition) or two (2-back condition) trials before. Genotypes of the COMT gene were determined through a saliva sample from all participants. Present results signifcantly showed lower working memory performance (p<0.05) in patients with fbromyalgia as compared to control participants (higher rate of errors and slower reaction times). At neural level, we found that patients exhibited enhanced frontocentral and parieto-occipital P2 amplitudes compared to control participants (p<0.05). Interestingly, we also observed that only fbromyalgia patients carrying the Val/Val genotype of the COMT gene showed higher frontocentral P2 amplitudes than control participants (p<0.05). Current results (behavioral outcomes and P2 amplitudes) confrmed the presence of an alteration in working memory functioning in fbromyalgia. The enhancement of frontocentral P2 could be refecting that these patients would manifest an inefcient way of activating executive attention processes, in carriers of the Val/Val genotype of COMT. To our knowledge, the present fndings are the frst linking neural indices of working memory dysfunctions and COMT genotypes in fbromyalgia. Applying a subgroup of patient’s strategy based on this genetic marker could be useful to establish more tailored therapeutical approaches.