Callosal microstructure affects the timing of electrophysiological left-right differences

“…The EEG dichotic listening paradigm was used and validated in two previous studies by ( 24 , 36 ). The paradigm was a passive dichotic listening task, with the stimuli consisting of six consonant-vowel syllable pairs (for example, “BA,” “DA,” “GA,” “KA,” “PA,” and “TA”).…”

Section: Methodsmentioning

confidence: 99%

Neurite architecture of the planum temporale predicts neurophysiological processing of auditory speech

et al. 2018

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“…The corpus callosum has a long history as an underlying factor of functional hemispheric asymmetries (Ocklenburg et al, 2016) and appears to decrease asymmetries in perceptual processes (e.g. Friedrich et al, 2017). However, this result does not hold true systematically as studies investigating speech processes (i.e.…”

Section: Discussionmentioning

confidence: 99%

Mapping the principal gradient onto the corpus callosum

Friedrich

Forkel

Schotten

2020

Preprint

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AbstractGradients capture some of the variance of the resting-state functional magnetic resonance imaging (rsfMRI) signal. Amongst these, the principal gradient depicts a functional processing hierarchy that spans from sensory-motor cortices to regions of the default-mode network. While the cortex has been well characterised in terms of gradients little is known about its underlying white matter. For instance, comprehensive mapping of the principal gradient on the largest white matter tract, the corpus callosum, is still missing. We hence mapped the principal gradient onto the callosal midsection using the 7T human connectome project dataset. We further explored how quantitative measures and variability in callosal midsection connectivity relate to the principal gradient values. In so doing, we demonstrated that the extreme values of the principal gradient are located within the callosal genu and the posterior body, have lower connectivity variability but a larger spatial extent along the midsection of the corpus callosum than mid-range values. Our results shed light on the relationship between the brain’s functional hierarchy and the corpus callosum. We further speculate about how these results may bridge the gap between functional hierarchy, brain asymmetries, and evolution.

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“…However, electrophysiological methods, especially cortical auditory evoked potentials (CAEPs), would help in understanding the neurophysiology of dichotic listening. Since the left hemisphere is dominant for speech and language function, CAEPs in DL is evidenced by larger amplitudes and shorter latencies over the left hemisphere ( Bayazit et al ., 2009; Eichele et al ., 2005; Friedrich et al ., 2017; Haaland, 1974; Morrell & Salamy, 1971). However, these studies have either focused on latency ( Eichele et al ., 2005) or amplitude ( Haaland, 1974; Morrell & Salamy, 1971), but not both.…”

Section: Introductionmentioning

confidence: 99%

“…Dichotic study involves the presentation of one stimulus to right ear and other stimulus to left ear. Previous studies have reported cortical changes using dichotic, but have not explored stimulus effect or order effect ( Bayazit et al ., 2009; Eichele et al ., 2005; Friedrich et al ., 2017; Haaland, 1974; Morrell & Salamy, 1971). The physiological responses elicited using different stimulus may differentially influence evoked ERPs, since these are obligatory responses to external stimuli.…”

Section: Introductionmentioning

confidence: 99%

Cortical auditory evoked potentials and hemispheric specialization of speech in individuals with learning disability and healthy controls: A preliminary study

et al. 2018

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Background: Dichotic listening (DL) technique is a behavioral non-invasive tool which is used in studying hemispheric lateralization. Previous studies using behavioral DL have hypothesized that individuals with learning disabilities (LD) exhibit a lack of cortical specialization for processing speech stimulus. However, there is no event related potential (ERP) evidence, hence the main objective of the study is to explore hemispheric asymmetry using cortical auditory evoked potential (CAEPs) in normal hearing adults and also to compare the same in children with LD and healthy controls. Methods: CAEPs were recorded in 16 normal hearing young adults, eight right-handed children with LD and their age matched controls. Two stop constants (/Pa/ – voiceless, bilabial, stop: /Ta/ - voiceless, alveolar, stop) were chosen for this experiment and presented in each ear and dichotically in two different orders (/pa-ta/, /ta-pa/). ERPs were processed using a standard pipeline, and electrodes readings over the left and right hemispheres were averaged to create left and right regions of interest (ROI). The CAEPs were analyzed for mean amplitude and peak latency of P1-N1-P2 components. Results: The current study results suggest no statistically significant difference between the two stimulus in monaural condition and absence of order effect in dichotic condition. In healthy controls the CAEP latencies were shorter over the left hemisphere in both monaural and dichotic conditions in adults and control children. However, it was very evident that such a difference was lacking in children with LD. Conclusions: Hemispheric asymmetry can be detected using CAEPs for speech stimulus. The measures are consistent and void of stimulus or order effect. Taken together, the findings of current study, both monaural and dichotic condition illustrates the hemispheric differences in processing speech stimuli in normal hearers. Absence of latency differences between hemispheres in children with LD indicate a lack of hemispheric asymmetry.

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Callosal microstructure affects the timing of electrophysiological left-right differences

Cited by 22 publications

References 81 publications

Neurite architecture of the planum temporale predicts neurophysiological processing of auditory speech

Neurite architecture of the planum temporale predicts neurophysiological processing of auditory speech

Mapping the principal gradient onto the corpus callosum

Cortical auditory evoked potentials and hemispheric specialization of speech in individuals with learning disability and healthy controls: A preliminary study

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