Emergence of β and γ networks following multisensory training

Abstract

Our perceptual reality relies on inferences about the causal structure of the world given by multiple sensory inputs. In ecological settings, multisensory events that cohere in time and space benefit inferential processes: hearing and seeing a speaker enhances speech comprehension, and the acoustic changes of flapping wings naturally pace the motion of a flock of birds. Here, we asked how a few minutes of (multi)sensory training could shape cortical interactions in a subsequent unisensory perceptual task. For this, we investigated oscillatory activity and functional connectivity as a function of individuals’ sensory history during training. Human participants performed a visual motion coherence discrimination task while being recorded with magnetoencephalography. Three groups of participants performed the same task with visual stimuli only, while listening to acoustic textures temporally comodulated with the strength of visual motion coherence, or with auditory noise uncorrelated with visual motion. The functional connectivity patterns before and after training were contrasted to resting-state networks to assess the variability of common task-relevant networks, and the emergence of new functional interactions as a function of sensory history. One major finding is the emergence of a large-scale synchronization in the high γ (gamma: ) and β (beta: ) bands for individuals who underwent comodulated multisensory training. The post-training network involved prefrontal, parietal, and visual cortices. Our results suggest that the integration of evidence and decision-making strategies become more efficient following congruent multisensory training through plasticity in network routing and oscillatory regimes.

Multisensory correlation computations in the human brain uncovered by a time-resolved encoding model

“…independent of specific task demands. The possibility that multisensory integration may be a default integrative mode for the representation of sensory signals supports recent findings 46 and is consistent with perceptual integration of multisensory dynamic structures 19,23 and speech processing 13,14 .…”

“…Auditory and visual signals that contain redundant information are typically generated by a common underlying physical cause and as such, they tend to correlate in time and space [10][11][12][13][14][15][16] . Moreover, a large body of literature demonstrates improved multisensory integration when the constituent unimodal signals correlate in time and space [17][18][19][20][21][22][23] . These findings point to spatio-temporal correlation as the primary cue for solving the correspondence problem.…”

Revisiting Functional Connectivity for Infraslow Scale-Free Brain Dynamics Using Complex Wavelets

“…This network comprises previously identified key brain regions (e.g., hMT+, ITC, vlPFC, and pSTS) during task performance. Interestingly, such regions also consistently identified as beubg recruited by a task when using standard temporal or spectral data analysis (Zilber et al, 2014 ; La Rocca et al, 2020 ). However, W-wPLI was the only index further showing that functional connectivity assessed from fractal dynamics actually increased during task performance in these regions.…”

“…Details regarding the source localization technique are reported in Zilber et al ( 2014 ). Finally, following analyses reported in Zilber et al ( 2014 ) and La Rocca et al ( 2020 ), 28 cortical regions-of-interest (ROIs), recruited in task performance (including frontal, somato-sensory, temporal, parietal, and occipital areas) were retained for the analysis of functional connectivity in infraslow temporal dynamics.…”

“…These indices were filtered at the group-level ( N = 36), using a recently introduced network density threshold method, the Efficiency Cost Optimization (De Vico Fallani et al, 2017 ), thus yielding group-level 28 × 28 fractal dynamics-based functional connectivity matrices across the brain for each experimental condition independently. See also La Rocca et al ( 2020 ) for further details on the use of such technique.…”