Biology subjects

Uwe Friese

Publications and source records attributed to Uwe Friese.

3 recordsLinked to original sources

bioRxiv2015

A matter of attention: Crossmodal congruence enhances and impairs performance in a novel trimodal matching paradigm

A novel crossmodal matching paradigm including vision, audition, and somatosensation was developed in order to investigate the interaction between attention and crossmodal congruence in multisensory integration. To that end, all three modalities were stimulated concurrently while a bimodal focus was defined blockwise. Congruence between stimulus intensity changes in the attended modalities had to be evaluated. We found that crossmodal congruence improved performance if both, the attended modalities and the task-irrelevant distractor were congruent. If the attended modalities were incongruent, the distractor impaired performance due to its congruence relation to one of the attended modalities. Between attentional conditions, magnitudes of crossmodal enhancement or impairment differed. Largest crossmodal effects were seen in visual-tactile matching, intermediate effects for audio-visual and smallest effects for audio-tactile matching. We conclude that differences in crossmodal matching likely reflect characteristics of multisensory neural network architecture. We discuss our results with respect to the timing of perceptual processing and state hypotheses for future physiological studies. Finally, etiological questions are addressed.

Neuroscience↗

bioRxiv2015

Large-scale cortical synchronization promotes multisensory processing: An EEG study of visual-tactile pattern matching

The integration of sensory signals from different modalities requires flexible interaction of remote brain areas. One candidate mechanism to establish communication in the brain is transient synchronization of oscillatory neural signals. Although there is abundant evidence for the involvement of cortical oscillations in brain functions based on the analysis of local power, assessment of the phase dynamics among spatially distributed neuronal populations and their relevance for behavior is still sparse. In the present study, we investigated the interaction between remote brain areas by analyzing high-density electroencephalogram (EEG) data obtained from human participants engaged in a visuotactile pattern matching task. We deployed an approach for purely data-driven clustering of neuronal phase coupling in source space, which allowed imaging of large-scale functional networks in space, time and frequency without defining a priori constraints. Based on the phase coupling results, we further explored how brain areas interacted across frequencies by computing phase-amplitude coupling. Several networks of interacting sources were identified with our approach, synchronizing their activity within and across the theta (~5 Hz), alpha (~10 Hz), and beta (~ 20 Hz) frequency bands and involving multiple brain areas that have previously been associated with attention and motor control. We demonstrate the functional relevance of these networks by showing that phase delays - in contrast to spectral power - were predictive of task performance. The data-driven analysis approach employed in the current study allowed an unbiased examination of functional brain networks based on EEG source level connectivity data. Showcased for multisensory processing, our results provide evidence that large-scale neuronal coupling is vital to long-range communication in the human brain and relevant for the behavioral outcome in a cognitive task.

Neuroscience↗

bioRxiv2015

Oscillatory signatures of crossmodal congruence effects: An EEG investigation employing a visuotactile pattern matching paradigm

Coherent percepts emerge from the accurate combination of inputs from the different sensory systems. There is ongoing debate about the neurophysiological implementation of crossmodal interactions in the brain, and it has been proposed that transient synchronization of neurons might be of central importance. Specifically, oscillatory activity in lower frequency ranges (< 30 Hz) has been implicated in mediating long-range communication as typically studied in multisensory research. In the current study, we recorded high-density electroencephalograms (EEG) while human participants were engaged in a visual-tactile pattern matching paradigm. Employing the same physical stimulation, separate tasks of the experiment either required the detection of predefined targets in visual and tactile modalities or the explicit evaluation of crossmodal stimulus congruence. Analysis of the behavioral data showed benefits for congruent visual-tactile stimulus combinations. Differences in oscillatory dynamics within the two tasks related to crossmodal congruence involved effects in the theta-(2-7 Hz), alpha-(813 Hz) and beta-band (13-25 Hz). Contrasting neuronal activity between the two tasks revealed differences in pre-stimulus alpha- and beta-band power, as well as differences in post-stimulus theta-band activity. Source reconstruction for these effects showed prominent involvement of superior temporal, parietal and prefrontal cortices - regions commonly implicated in multisensory integration. These results add to the increasing evidence that low frequency oscillations are well suited for studying integration in distributed brain networks, as demonstrated for crossmodal interactions in visual-tactile pattern matching in the current study. Additionally, neuronal activity at theta-, alpha- and beta-frequencies might subserve distinct processes relevant for multisensory integration, such as multisensory gating and crossmodal perceptual decision making.

Neuroscience↗