Background: Recovery from stroke-induced aphasia is typically protracted and involves complex functional reorganization. The relative contributions of the lesioned and non-lesioned hemispheres to this process have been examined in several cross-sectional studies but longitudinal studies involving several time-points and large numbers of subjects are scarce.
Objective: The aim of this study was to address the gaps in the literature by longitudinally studying the evolution of post-stroke lateralization and localization of language-related fMRI activation in the first year after single left hemispheric ischemic stroke.
Method: Seventeen patients with stroke-induced aphasia were enrolled to undergo detailed behavioral testing and fMRI at 2, 6, 12, 26, and 52 weeks post-stroke. Matched for age, handedness and sex participants were also enrolled to visualize canonical language regions.
Results: Behavioral results showed improvements over time for all but one of the behavioral scores (Semantic Fluency Test). FMRI results showed that the left temporal area participates in compensation for language deficits in the first year after stroke, that there is a correlation between behavioral improvement and the left cerebellar activation over time, and that there is a shift towards stronger frontal left-lateralization of the fMRI activation over the first year post-stroke. Temporary compensation observed in the initial phases of post-stroke recovery that involves the non-lesioned hemisphere may not be as important as previously postulated, since in this study the recovery was driven by activations in the left fronto-temporal regions.
Conclusion: Language recovery after left hemispheric ischemic stroke is likely driven by the previously involved in language and attention left hemispheric networks.
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http://dx.doi.org/10.3233/RNN-170767 | DOI Listing |
J Neurosci Res
January 2025
Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de Mexico, Mexico.
Lateralization of motor behavior, a common phenomenon in humans and several species, is modulated by the basal ganglia, a site pointed out for the interhemispheric differences related to lateralization. Our study aims to shed light on the potential role of the striatonigral D1 receptor in functional asymmetry in normal conditions through neurochemical and behavioral means. We found that D1 receptor activation and D1/D3 receptor coactivation in striatonigral neurons leads to more cAMP production by adenylyl cyclase in the striatum and GABA release in their terminals in the right hemisphere compared to the left.
View Article and Find Full Text PDFBrain Res
December 2024
Beijing Key Laboratory of Central Nervous System Injury, Beijing Neurosurgical Institute, Capital Medical University, Beijing 10070, China; Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 10070, China; U1195, Inserm et Universite Paris-Saclay, 94276 Le Kremlin-Bicetre, France. Electronic address:
Objective: Peripheral nerve injury results in functional alterations of the corresponding active brain areas, which are closely related to functional recovery. Whether such functional plasticity induces relative anatomical structural changes remains to be investigated.
Methods: In this study, we investigated the changes in brain cortical thickness in patients with facial paralysis following neurorrhaphy treatment at different follow-up times.
Netw Neurosci
December 2024
Department of Clinical Cognition Science, Clinic of Neurology at the RWTH Aachen University Faculty of Medicine, ZBMT, Aachen, Germany.
Networks in the parietal and premotor cortices enable essential human abilities regarding motor processing, including attention and tool use. Even though our knowledge on its topography has steadily increased, a detailed picture of hemisphere-specific integrating pathways is still lacking. With the help of multishell diffusion magnetic resonance imaging, probabilistic tractography, and the Graph Theory Analysis, we investigated connectivity patterns between frontal premotor and posterior parietal brain areas in healthy individuals.
View Article and Find Full Text PDFCureus
November 2024
Department of Neurosurgery, Fukushima Medical University, Fukushima, JPN.
Introduction The degree to which each human brain hemisphere governs specific cognitive processes, such as language and handedness (the preference or dominance of one hand over the other), varies across individuals. Research has explored the nature of language laterality in left-handed (LH) individuals, indicating that left-hemisphere dominance for language is commonly observed across both left- and right-handed populations. Advanced imaging techniques, including functional transcranial Doppler sonography and fMRI, have revealed subtle differences in language lateralization between LH and right-handed (RH) individuals, particularly in semantic processing tasks.
View Article and Find Full Text PDFBrain Cogn
December 2024
Department of Neuroscience, University of Padova, Italy; Padova Neuroscience Center, University of Padova, Italy. Electronic address:
Mixed Transcortical Aphasia (MTA) is an infrequent aphasic syndrome, characterized by poor comprehension and production in oral language abilities and poor performance in written language abilities. However, individuals with MTA typically retain the ability to repeat. Our patient, a woman who suffered from a left hemisphere ischemic stroke involving perisylvian areas, presented with repetition preserved for words, non-words, sentences and numbers, together with marginally preserved reading abilities.
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