Two successive phases in the threat-related attentional response of anxious subjects: neural correlates.

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.