Visual testing conjuction vs easy eeg
It acts out stimulus perception as well as feature-detection mechanisms and represents fundamental auditory processing. While the MMN reflects active sensory memory processing, the N1 as its prerequisite contributes to encoding the sensory memory trace. Some report decreased MMN amplitudes in the secondary task, , others find the opposite, and there also exist null-findings on potential crossmodal influences, , ). Results show inconsistencies regarding the directionality of crossmodal effects. Most studies focused on the auditory change effects. One family of crossmodal effects are primary visual load effects on secondary auditor processing. This may be caused by the challenging task in the primary modality, which supports the notion of attention being a general, modality-independent cognitive resource serving beneficial purposes for other modalities. In contrast to the gain-load theory, the effects expected here on secondary task processing are beneficial rather than detrimental.Īnother alternative explanation for advantageous crossmodal effects may include generalized attention, a concept attributed to a spread of cognitive alertness. The decrease in executive control challenged the otherwise effective suppression of irrelevant input. This was interpreted as a consequence of executive control due to cognitive overload resulting from the attended task. In a perceptually demanding visual attentional blink paradigm healthy young participants showed cross-modal augmentation processing of unattended sounds. Recently, Haroush and colleagues have reported evidence for yet another alternative. reduced distraction effect but intact automatic change-detection mechanisms, ). This was also supported by others and moderated by the assumption of differential effects on undistractable and distractable components of crossmodal attention (e.g. In contrast, the ‘gain-load theory’ suggests that the primarily engaged modality uses the limited capacities which causes inhibition and thereby decreased processing of secondary input. Several studies have found evidence for an absence of crossmodal effects on secondary task processing. The results can be subsumed under different theoretical frameworks: The ‘automaticity theory’ states automatic processing to be present in the unattended secondary task and immunity to cross-modal influences. Cross-modal processing has been subject to several experimental investigations. How limited processing resources are managed between sensory modalities which are implicated simultaneously via two or more different tasks is however not fully understood. The brain’s capacity to re-allocate resources and to deal with its attentional capacities is relevant for survival and serves adaptive functioning. We suggest a continuous allocation of resources to brain regions processing primary tasks when challenging the central executive under high cognitive load. These results suggest differential effects of crossmodal attention on fundamental auditory processing. With increasing WM load, primary auditory cortices were increasingly deactivated while psychophysiological interaction results suggested the emergence of auditory cortices connectivity with visual WM regions. Amplitudes of auditory evoked potentials, representing fundamental auditory processing showed a continuous augmentation which demonstrated a systematic relation to cross-modal cognitive load. This was accompanied by significantly higher reaction times and lower hit rates with increasing task difficulty which confirmed successful manipulation of WM load. The fMRI results revealed fronto-parietal WM network activations in response to T1 task manipulation. The primary task (T1) was to respond to a visual working memory (WM) task with four conditions, while the secondary task (T2) consisted of an auditory oddball stream, which participants were asked to ignore. Data from 8 participants were obtained outside the scanner for validation purposes.
15 healthy participants underwent a simultaneous EEG-fMRI experiment. We manipulated cognitive load within one modality (visual) and studied the consequences of cognitive demands on secondary (auditory) processing.
This contrasts findings of cognitive load compromising a secondary modality’s processing. Cognitive task demands in one sensory modality (T1) can have beneficial effects on a secondary task (T2) in a different modality, due to reduced top-down control needed to inhibit the secondary task, as well as crossmodal spread of attention.