Studying electroencephalography (EEG) in response to transcranial magnetic stimulation (TMS) is gaining popularity for investigating the dynamics of complex neural architecture in the brain. For example, the primary motor cortex (M1) executes voluntary movements by complex connections with other associated subnetworks. To understand these connections better, we analyzed EEG signal response to TMS at left M1 from schizophrenia patients and healthy controls and in contrast with resting state EEG recording. After removing artifacts from EEG, we conducted 2D to 3D sLORETA conversion, a well-established source localization method, for estimating signal strength of 68 source dipoles or cortical regions inside the brain. Next, we studied dynamic connectivity by computing time-evolving spatial coherence of 2278 (=68*(68-1)/2) pairs of cortical regions, with sliding window technique of 200ms window size and 20ms shift over 1sec long data. Pairs with consistent coherence (coherence>0.8 during 200+ sliding windows of patients and controls combined) were chosen for identifying stable networks. For example, we found that during the resting state, precuneus was steadily coherent with middle and superior temporal gyrus in the left hemisphere in both patient and controls. Their connectivity pattern over the sliding windows significantly differed between patients and controls (pvalue<0.05). Whereas for M1, the same was true for two other coherent pairs namely, superamarginal gyrus with lateral occipital gyrus in right hemisphere and medial orbitofrontal gyrus with fusiform in left hemisphere. The TMS-EEG dynamic connectivity results can help to differentiate patient and normal subjects and also help to better understand the brain architecture and mechanisms.
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Neural Correlates of Audiovisual Temporal Binding Window in Individuals With Schizotypal and Autistic Traits: Evidence From Resting‐State Functional Connectivity
Temporal proximity is an important clue for multisensory integration. Previous evidence indicates that individuals with autism and schizophrenia are more likely to integrate multisensory inputs over a longer temporal binding window (TBW). However, whether such deficits in audiovisual temporal integration extend to subclinical populations with high schizotypal and autistic traits are unclear. Using audiovisual simultaneity judgment (SJ) tasks for nonspeech and speech stimuli, our results suggested that the width of the audiovisual TBW was not significantly correlated with self‐reported schizotypal and autistic traits in a group of young adults. Functional magnetic resonance imaging (fMRI) resting‐state activity was also acquired to explore the neural correlates underlying inter‐individual variability of TBW width. Across the entire sample, stronger resting‐state functional connectivity (rsFC) between the left superior temporal cortex and the left precuneus, and weaker rsFC between the left cerebellum and the right dorsal lateral prefrontal cortex were correlated with a narrower TBW for speech stimuli. Meanwhile, stronger rsFC between the left anterior superior temporal gyrus and the right inferior temporal gyrus was correlated with a wider audiovisual TBW for non‐speech stimuli. The TBW‐related rsFC was not affected by levels of subclinical traits. In conclusion, this study indicates that audiovisual temporal processing may not be affected by autistic and schizotypal traits and rsFC between brain regions responding to multisensory information and timing may account for the inter‐individual difference in TBW width.
Individuals with ASD and schizophrenia are more likely to perceive asynchronous auditory and visual events as occurring simultaneously even if they are well separated in time. We investigated whether similar difficulties in audiovisual temporal processing were present in subclinical populations with high autistic and schizotypal traits. We found that the ability to detect audiovisual asynchrony was not affected by different levels of autistic and schizotypal traits. We also found that connectivity of some brain regions engaging in multisensory and timing tasks might explain an individual's tendency to bind multisensory information within a wide or narrow time window.
- PAR ID:
- 10452354
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Autism Research
- Volume:
- 14
- Issue:
- 4
- ISSN:
- 1939-3792
- Page Range / eLocation ID:
- p. 668-680
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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