Lower Interhemispheric Coherence in a Case of Agenesis of the Corpus Callosum

Nagase, Yukihiro; Terasaki, Omi; Okubo, Yoshiro; Toru, Michio

doi:10.1177/155005949402500110

Cited by 16 publications

(14 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…An fMRI case study of three individuals with AgCC demonstrated reduced functional connectivity in regions serving auditory, motor and language processing, although with such a small sample size, the statistical significance of this reduced connectivity was difficult to determine [73]. In EEG, reductions in resting-state alpha coherence have been repeatedly reported in individuals with AgCC, generally between frontal and central scalp electrodes [72], [75]–[76]. The precision of source localization inherent to MEG-I analyses used in the present study allows us to target which brain areas are specifically underconnected in callosal dysgenesis, a step far beyond the limitations of EEG spatial resolution.…”

Section: Discussionmentioning

confidence: 99%

The Role of Corpus Callosum Development in Functional Connectivity and Cognitive Processing

et al. 2012

View full text Add to dashboard Cite

The corpus callosum is hypothesized to play a fundamental role in integrating information and mediating complex behaviors. Here, we demonstrate that lack of normal callosal development can lead to deficits in functional connectivity that are related to impairments in specific cognitive domains. We examined resting-state functional connectivity in individuals with agenesis of the corpus callosum (AgCC) and matched controls using magnetoencephalographic imaging (MEG-I) of coherence in the alpha (8–12 Hz), beta (12–30 Hz) and gamma (30–55 Hz) bands. Global connectivity (GC) was defined as synchronization between a region and the rest of the brain. In AgCC individuals, alpha band GC was significantly reduced in the dorsolateral pre-frontal (DLPFC), posterior parietal (PPC) and parieto-occipital cortices (PO). No significant differences in GC were seen in either the beta or gamma bands. We also explored the hypothesis that, in AgCC, this regional reduction in functional connectivity is explained primarily by a specific reduction in interhemispheric connectivity. However, our data suggest that reduced connectivity in these regions is driven by faulty coupling in both inter- and intrahemispheric connectivity. We also assessed whether the degree of connectivity correlated with behavioral performance, focusing on cognitive measures known to be impaired in AgCC individuals. Neuropsychological measures of verbal processing speed were significantly correlated with resting-state functional connectivity of the left medial and superior temporal lobe in AgCC participants. Connectivity of DLPFC correlated strongly with performance on the Tower of London in the AgCC cohort. These findings indicate that the abnormal callosal development produces salient but selective (alpha band only) resting-state functional connectivity disruptions that correlate with cognitive impairment. Understanding the relationship between impoverished functional connectivity and cognition is a key step in identifying the neural mechanisms of language and executive dysfunction in common neurodevelopmental and psychiatric disorders where disruptions of callosal development are consistently identified.

show abstract

Section: Discussionmentioning

confidence: 99%

The Role of Corpus Callosum Development in Functional Connectivity and Cognitive Processing

et al. 2012

View full text Add to dashboard Cite

show abstract

“…This is further supported by electrophysiological studies reporting decreased interhemispheric coupling in patients with callosal agenesis [Brown et al, 1998; Koeda et al, 1999; Nagase et al, 1994; van de Wassenberg et al, 2008] and reduced resting state functional connectivity following callosal transection [Johnston et al, 2008]. In multiple sclerosis (MS), an inflammatory, demyelinating disorder of the nervous system, focal lesions within the CC and Wallerian degeneration from adjacent hemispheric white matter lesions are thought to result in atrophy of the CC [Klawiter et al, 2015].…”

Section: Introductionmentioning

confidence: 92%

A surface‐based technique for mapping homotopic interhemispheric connectivity: Development, characterization, and clinical application

Tobyne

Daria

Johnson

et al. 2016

Human Brain Mapping

View full text Add to dashboard Cite

The functional organization of the human brain consists of a high degree of connectivity between inter-hemispheric homologous regions. The degree of homotopic organization is known to vary across the cortex and homotopic connectivity is high in regions that share cross-hemisphere structural connections or are activated by common input streams (e.g. the visual system). Damage to one or both regions, as well as damage to the connections between homotopic regions, could disrupt this functional organization. Here were introduce and test a computationally efficient technique, surface-based Homotopic Inter-hermispheric Connectivity (sHIC), that leverages surface-based registration and processing techniques in an attempt improve the spatial specificity and accuracy of cortical inter-hemispheric connectivity estimated with resting state functional connectivity. This technique is shown to be reliable both within and across subjects. sHIC is also characterized in a dataset of nearly 1000 subjects. We confirm previous results showing increased inter-hemispheric connectivity in primary sensory regions, and reveal a novel rostro-caudal functionally-defined network level pattern of sHIC across the brain. In addition, we demonstrate a structural-functional relationship between sHIC and atrophy of the corpus callosum in multiple sclerosis (r=0.2979, p=0.0461). sHIC presents as a sensitive and reliable measure of cortical homotopy that may prove useful as a biomarker in neurologic disease.

show abstract

“…In many cases, EEG functional connectivity has been shown to reflect the underlying structural properties of the brain. For example, coherence between electrodes placed on each hemisphere is weakened in individuals with surgically sectioned or underdeveloped commissural white matter fibres (Koeda et al, 1995;Montplaisir et al, 1990;Nagase, Terasaki, Okubo, Matsuura, & Toru, 1994;Nielsen, Montplaisir, & Lassonde, 1993). Furthermore, studies have noted positive correlations between functional EEG coherence and white matter tract integrity in patients with M A N U S C R I P T…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Resting-state EEG power and connectivity are associated with alpha peak frequency slowing in healthy aging

Scally

Burke

Bunce

et al. 2018

Neurobiology of Aging

174

129

View full text Add to dashboard Cite

The individual alpha peak frequency (IAPF) of the human electroencephalography (EEG) typically experiences slowing with increasing age. Despite this hallmark change, studies that investigate modulations of conventional EEG alpha power and connectivity by aging and age-related neuropathology neglect to account for intergroup differences in IAPF. To investigate the relationship of age-related IAPF slowing with EEG power and connectivity, we recorded eyes-closed resting-state EEG in 37 young adults and 32 older adults. We replicated the finding of a slowed IAPF in older adults. IAPF values were significantly correlated with the frequency of maximum global connectivity and the means of their distributions did not differ, suggesting that connectivity was highest at the IAPF. Older adults expressed reduced global EEG power and connectivity at the conventional upper alpha band (10-12 Hz) compared with young adults. By contrast, groups had equivalent power and connectivity at the IAPF. The results suggest that conventional spectral boundaries may be biased against older adults or any group with a slowed IAPF. We conclude that investigations of alpha activity in aging and age-related neuropathology should be adapted to the IAPF of the individual and that previous findings should be interpreted with caution. EEG in the dominant alpha range may be unsuitable for examining cortico-cortical connectivity due to its subcortical origins.

show abstract

Lower Interhemispheric Coherence in a Case of Agenesis of the Corpus Callosum

Cited by 16 publications

References 11 publications

The Role of Corpus Callosum Development in Functional Connectivity and Cognitive Processing

The Role of Corpus Callosum Development in Functional Connectivity and Cognitive Processing

A surface‐based technique for mapping homotopic interhemispheric connectivity: Development, characterization, and clinical application

Resting-state EEG power and connectivity are associated with alpha peak frequency slowing in healthy aging

Contact Info

Product

Resources

About