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 (n=27) 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. Depression and Anxiety, 2009.

Objective: Cognitive dysfunction in fibromyalgia has become a key symptom considered by patients as more disabling than pain itself. Experimental evidence from neuropsychological and neuroimaging studies indicates that such cognitive impairments are especially robust when patients need to set in motion working memory processes, suggesting the existence of an altered functioning underlying the cerebral cortices of the frontoparietal memory network. However, the temporal dynamics of working memory subprocesses have not yet been explored in fibromyalgia. Subjects: Thirty-six right-handed women participated in the experiment, comprising 18 patients with fibromyalgia and 18 healthy controls. Methods: Event-related potentials (ERPs) and behavioral responses were recorded while participants were engaged in a two-back working memory task. Principal component analyses were used to define and quantify the ERP components associated with working memory processes. Results: Patients with fibromyalgia exhibited worse performance than the control group, as revealed by their number of errors in the working memory task. Moreover, both scalp parieto-occipital P2 and parieto-occipital P3 amplitudes were lower for patients than for healthy control participants. Regression analyses revealed that lower P3 amplitudes were observed in those patients with fibromyalgia reporting higher pain ratings. Conclusions: The present results suggest that both encoding of information (as reflected by P2) and subsequently context updating and replacement (as seen in lower P3 amplitudes), as a part of working memory subprocesses, are impaired in fibromyalgia. Studying the temporal dynamics of working memory through the use of ERP methodology is a helpful approach to detect specific impaired cognitive mechanisms in this chronic pain syndrome. These new data could be used to develop more specific treatments adapted for each patient.

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 different identities. Each model displays one neutral expression and three pain-related facial expressions: posed, spontaneous-algometer and spontaneous-CO₂laser. Normative ratings of pain intensity, valence and arousal were provided by students of three different 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 effects 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 differential effects 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.

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. 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. 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. 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.