Functional characteristics of control adaptation in intermodal sensory processing.

The present work investigated functional characteristics of control adjustments in intermodal sensory processing. Subjects performed an interference task that involved simultaneously presented visual and auditory stimuli which were either congruent or incongruent with respect to their response mappings. In two experiments, trial-by-trial sequential congruency effects were analysed for specific conditions that allowed ruling out "non-executive" contributions of stimulus or response priming to the respective RT fluctuations. In Experiment 1, conflict adaptation was observed in an oddball condition in which interference emanates from a task-irrelevant and response-neutral low-frequency stimulus. This finding characterizes intermodal control adjustments to be based - at least partly - on increased sensory selectivity, which is able to improve performance in any kind of interference condition which shares the same or overlapping attentional requirements. In order to further specify this attentional mechanism, Experiment 2 defined analogous conflict adaptation effects in non-interference unimodal trials in which just one of the two stimulus modalities was presented. Conflict adaptation effects in unimodal trials exclusively occurred for unimodal task-switch trials but not for otherwise equivalent task repetition trials, which suggests that the observed conflict-triggered control adjustments mainly consist of increased distractor inhibition (i.e., down-regulation of task-irrelevant information), while attributing a negligible role to target amplification (i.e., enhancement of task-relevant information) in this setup. This behavioral study yields a promising operational basis for subsequent neuroimaging investigations to define brain activations and connectivities which underlie the adaptive control of attentional selection.

Short-Term Audiovisual Spatial Training Enhances Electrophysiological Correlates of Auditory Selective Spatial Attention.

Audiovisual cross-modal training has been proposed as a tool to improve human spatial hearing. Here, we investigated training-induced modulations of event-related potential (ERP) components that have been associated with processes of auditory selective spatial attention when a speaker of interest has to be localized in a multiple speaker ("cocktail-party") scenario. Forty-five healthy participants were tested, including younger (19-29 years; n = 21) and older (66-76 years; n = 24) age groups. Three conditions of short-term training (duration 15 min) were compared, requiring localization of non-speech targets under "cocktail-party" conditions with either (1) synchronous presentation of co-localized auditory-target and visual stimuli (audiovisual-congruency training) or (2) immediate visual feedback on correct or incorrect localization responses (visual-feedback training), or (3) presentation of spatially incongruent auditory-target and visual stimuli presented at random positions with synchronous onset (control condition). Prior to and after training, participants were tested in an auditory spatial attention task (15 min), requiring localization of a predefined spoken word out of three distractor words, which were presented with synchronous stimulus onset from different positions. Peaks of ERP components were analyzed with a specific focus on the N2, which is known to be a correlate of auditory selective spatial attention. N2 amplitudes were significantly larger after audiovisual-congruency training compared with the remaining training conditions for younger, but not older, participants. Also, at the time of the N2, distributed source analysis revealed an enhancement of neural activity induced by audiovisual-congruency training in dorsolateral prefrontal cortex (Brodmann area 9) for the younger group. These findings suggest that cross-modal processes induced by audiovisual-congruency training under "cocktail-party" conditions at a short time scale resulted in an enhancement of correlates of auditory selective spatial attention.

Cognitive Biases Toward Pain: Implications for a Neurocognitive Processing Perspective in Chronic Pain and its Interaction With Depression.

OBJECTIVES: Information-processing biases such as attentional, interpretation, and memory biases are supposed to play a role in the exacerbation and maintenance of chronic pain. Current research in the area of cognitive biases shows that all these biases seem to have an influence on attention to, interpretation of, and recall of pain and can lead to maladaptive strategies and the exacerbation of pain. METHODS: We conducted a narrative literature review, considering evidence extracted from various databases including PubMed, MEDLINE, Science Direct, and ProQuest. Search terms included cognitive biases, neurocognitive processing, chronic pain, and depression. RESULTS: The literature on attentional, interpretative, and memory biases in experimental and chronic pain, as well as their neuronal underpinnings, suggests that the depression of chronic pain patients may differ from the depression of patients without pain. Depressed pain patients show a recall bias for illness-related and health-related stimuli, whereas depressed patients without pain show a bias for depression-related stimuli. In addition, research has shown that catastrophizing, helplessness/hopelessness, and thought suppression as psychological responses to pain are mediators of the relationship between chronic pain and depression. CONCLUSIONS: Current research supports the importance of individual diagnosis of chronic pain patients and their response patterns of pain, psychological processing, and information processing. This leads to the conclusion that depressed pain patients need other clinical interventions when compared with depressed patients without pain. Previous research showed that a combination of a cognitive-behavioral therapy with mindfulness meditation seems to be a promising approach.

Cortical processing of location changes in a "cocktail-party" situation: Spatial oddball effects on electrophysiological correlates of auditory selective attention.

Neural mechanisms of selectively attending to a sound source of interest in a simulated "cocktail-party" situation, composed of multiple competing sources, were investigated using event-related potentials in combination with a spatial oddball design. Subjects either detected rare spatial deviants in a series of standard sounds or passively listened. Targets either appeared in isolation or in the presence of two distractor sound sources at different locations ("cocktail-party" condition). Deviant-minus-standard difference potentials revealed mismatch negativity, P3a, and P3b. However, mainly the P3b was modulated by spatial conditions of stimulation, with lower amplitude for "cocktail-party", than single, sounds. In the active condition, cortical source localization revealed two distinct foci of maximum differences in electrical activity for the contrast of single vs. "cocktail-party" sounds: the right inferior frontal junction and the right anterior superior parietal lobule. These areas may be specifically involved in processes associated with selective attention in a "cocktail-party" situation.