Abnormal interhemispheric motor interactions in patients with callosal agenesis

Genç, Erhan; Ocklenburg, Sebastian; Singer, Wolf; Güntürkün, Onur

doi:10.1016/j.bbr.2015.07.016

Cited by 32 publications

(14 citation statements)

References 62 publications

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“…Compared with other common schemes, such as Witelson’s37 or Huang’s schemes38, Hofer’s strategy is more precise, as it accounts for a clear separation of callosal prefrontal, premotor and primary motor fiber bundles. Therefore, the current applied scheme is widely accepted in network and CC studies394041. According to Hofer’s scheme, our findings point to abnormal WM integrity in region II of the CC, which supports our first hypothesis that CC subregion may be involved in brain reorganization following amputation.…”

Section: Discussionsupporting

confidence: 81%

Altered microstructure rather than morphology in the corpus callosum after lower limb amputation

Fan

et al. 2017

Sci Rep

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The corpus callosum (CC) has been implicated in the reorganization of the brain following amputation. However, it is unclear which regions of the CC are involved in this process. In this study, we explored the morphometric and microstructural changes in CC subregions in patients with unilateral lower limb amputation. Thirty-eight patients and 38 age- and gender-matched normal controls were included. The CC was divided into five regions, and the area, thickness and diffusion parameters of each region were investigated. While morphometric analysis showed no significant differences between the two groups, amputees showed significant higher values in axial diffusivity, radial diffusivity and mean diffusivity in region II of the CC, which connects the bilateral premotor and supplementary motor areas. In contrast, the mean fractional anisotropy value of the fibers generated by these cortical areas, as measured by tractography, was significantly smaller in amputees. These results demonstrate that the interhemispheric pathways contributing to motor coordination and imagery are reorganized in lower limb amputees.

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Section: Discussionsupporting

confidence: 81%

Altered microstructure rather than morphology in the corpus callosum after lower limb amputation

Fan

et al. 2017

Sci Rep

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“…As a consequence, the dominant left hemisphere is able to inhibit the subdominant right. Inhibitory interactions are possibly crucial when only one function for which one hemisphere is dominant has to be executed [48]. Against this background, we will discuss our findings.…”

Section: Discussionmentioning

confidence: 78%

“…It is more likely that the causal mechanisms for re-activation of the left eye system are related to the short-term synaptic plasticity of the strength of commissural synapses. As the dominant left hemisphere is able to inhibit the subdominant right [47,48], the functional asymmetry of the magnetic compass could be constituted via asymmetrically organized inhibitory interactions between the two hemispheres. Both the left and the right hemispheres are obviously able to do the task during the first spring migration, but, under normal conditions, the dominant left hemisphere (right eye) would inhibit the subdominant right half brain (left eye).…”

Section: Fast Re-activation Of the Left Eye/right Hemisphere System Fmentioning

confidence: 99%

Lateralization of the Avian Magnetic Compass: Analysis of Its Early Plasticity

et al. 2017

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Abstract:In European Robins, Erithacus rubecula, the magnetic compass is lateralized in favor of the right eye/left hemisphere of the brain. This lateralization develops during the first winter and initially shows a great plasticity. During the first spring migration, it can be temporarily removed by covering the right eye. In the present paper, we used the migratory orientation of robins to analyze the circumstances under which the lateralization can be undone. Already a period of 1 1 /2 h being monocularly left-eyed before tests began proved sufficient to restore the ability to use the left eye for orientation, but this effect was rather short-lived, as lateralization recurred again within the next 1 1 /2 h. Interpretable magnetic information mediated by the left eye was necessary for removing the lateralization. In addition, monocularly, the left eye seeing robins could adjust to magnetic intensities outside the normal functional window, but this ability was not transferred to the "right-eye system". Our results make it clear that asymmetry of magnetic compass perception is amenable to short-term changes, depending on lateralized stimulation. This could mean that the left hemispheric dominance for the analysis of magnetic compass information depends on lateralized interhemispheric interactions that in young birds can swiftly be altered by environmental effects.

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“…Only very few clinical reports, let alone systematic studies, on the consequences for language processing of direct damage to callosal fibres connecting left and right inferior frontal cortex are available. Mostly, callosal dysfunction in relation to language was investigated in the context of congenital callosal disorders like agenesis or dysgenesis of the CC (Brown, Symingtion, VanLancker‐Sidtis, Dietrich, & Paul, ; Genç, Ocklenburg, Singer, & Güntürkün, ; Jeeves & Temple, ; Paul, Van Lancker‐Sidtis, Schieffer, Dietrich, & Brown, ; Sanders, ). These studies have identified deficits in phonological and syntactic processing in relation to congenital CC dysfunction (Jeeves & Temple, ; Paul et al., ; Sanders, ; Temple, Jeeves, & Vilarroya, ).…”

Section: Discussionmentioning

confidence: 99%

A transcallosal fibre system between homotopic inferior frontal regions supports complex linguistic processing

Kellmeyer

Vry

Ball

2019

Eur J of Neuroscience

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Inferior frontal regions in the left and right hemisphere support different aspects of language processing. In the canonical model, left inferior frontal regions are mostly involved in processing based on phonological, syntactic and semantic features of language, whereas the right inferior frontal regions process paralinguistic aspects like affective prosody. Using diffusion tensor imaging (DTI)‐based probabilistic fibre tracking in 20 healthy volunteers, we identify a callosal fibre system connecting left and right inferior frontal regions that are involved in linguistic processing of varying complexity. Anatomically, we show that the interhemispheric fibres are highly aligned and distributed along a rostral to caudal gradient in the body and genu of the corpus callosum to connect homotopic inferior frontal regions. In the light of converging data, taking previous DTI‐based tracking studies and clinical case studies into account, our findings suggest that the right inferior frontal cortex not only processes paralinguistic aspects of language (such as affective prosody), as purported by the canonical model, but also supports the computation of linguistic aspects of varying complexity in the human brain. Our model may explain patterns of right‐hemispheric contribution to stroke recovery as well as disorders of prosodic processing. Beyond language‐related brain function, we discuss how inter‐species differences in interhemispheric connectivity and fibre density, including the system we described here may also explain differences in transcallosal information transfer and cognitive abilities across different mammalian species.

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Abnormal interhemispheric motor interactions in patients with callosal agenesis

Cited by 32 publications

References 62 publications

Altered microstructure rather than morphology in the corpus callosum after lower limb amputation

Altered microstructure rather than morphology in the corpus callosum after lower limb amputation

Lateralization of the Avian Magnetic Compass: Analysis of Its Early Plasticity

A transcallosal fibre system between homotopic inferior frontal regions supports complex linguistic processing

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