EditorialNeurorehabilitation: Neural Plasticity and FunctionalRecovery 2018

Toshiyuki Fujiwara ,1 Junichi Ushiba,2,3,4 and Surjo R. Soekadar 5,6

1Department of Rehabilitation Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo,Tokyo 113-8421, Japan2Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan3Keio Institute of Pure and Applied Sciences (KiPAS), Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama,Kanagawa 223-8522, Japan4Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku,Yokohama, Kanagawa 223-8522, Japan5Clinical Neurotechnology Laboratory, Department of Psychiatry and Psychotherapy, Neuroscience Research Center (NWFZ),Charité-University Medicine Berlin, Germany6Department of Psychiatry and Psychotherapy, Eberhard-Karls-University Tübingen, Germany

Correspondence should be addressed to Surjo R. Soekadar; surjo.soekadar@charite.de

Received 15 November 2018; Accepted 6 December 2018; Published 21 January 2019

Copyright © 2019 Toshiyuki Fujiwara et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

Over the last decades, many axiomatic and dominating viewson the functional architecture and workings of the mamma-lian central nervous system (CNS) had to be fundamentallyreconsidered. Although the dominating view that the maturemammalian CNS is structurally immutable was repeatedlychallenged, e.g., by studies showing collateral axonal sprout-ing and intracortical synaptic plasticity after a spinal cordinjury (SCI) in cats [1, 2], the capacity of the lesioned CNSto reorganize was only fully appreciated after Merzenichand colleagues introduced their famous deafferentation stud-ies in the 1980s [3, 4]. Besides showing that topographic cor-tical representations are maintained dynamically throughoutlife, they also provided compelling evidence that thisself-organizing capacity of the CNS can relate to neurologicalrecovery [5–7].

Based on this new understanding of CNS plasticity andthe factors driving it, Taub et al. introduced a novel rehabil-itation procedure that now belongs to the established reper-toire of physiotherapists worldwide (Constraint-InducedMovement Therapy, CIMT) [7–9]. Being a good examplefor the successful translation of insights from basic researchfindings collected over several decades in animal studies into

a new treatment strategy used in hospitals all over the world,the development of CIMT also exemplifies the long, strenu-ous and often very difficult path from bench to bedside.

This special issue acknowledges this challenging path andprovides a forum for presenting the latest views and findingsin the field of neurorehabilitation. Besides featuring a com-prehensive review on the state-of-the-art in experimentalstroke research by A.-S. Wahl (“State-of-the-Art Techniquesto Causally Link Neural Plasticity to Functional Recovery inExperimental Stroke Research”) and cognitive rehabilitationin Parkinson’s disease by M. Díez-Cirarda et al. (“Neuroreh-abilitation in Parkinson’s Disease: A Critical Review of Cog-nitive Rehabilitation Effects on Cognition and Brain”), thisspecial issue includes a study by S.-L. Liew et al. that evalu-ated brain activity during action observation of 24 strokesurvivors and 12 age-matched healthy controls using func-tional magnetic resonance imaging (fMRI) (“Laterality ofPoststroke Cortical Motor Activity during Action Observa-tion Is Related to Hemispheric Dominance”). They foundthat action observation is lateralized to the dominant, ratherthan ipsilesional, hemisphere. As this may reflect an interac-tion between the lesioned hemisphere and the dominant

HindawiNeural PlasticityVolume 2019, Article ID 7812148, 3 pageshttps://doi.org/10.1155/2019/7812148

hemisphere in driving lateralization of brain activity afterstroke, they conclude that this finding should be carefullyconsidered when characterizing poststroke neural activity.

M. R. Pereira-Jorge et al. (“Anatomical and FunctionalMRI Changes after One Year of Auditory Rehabilitation withHearing Aids”) describe the anatomical and functional MRIchanges related to one year of auditory rehabilitation withhearing aids (HA) across 14 individuals diagnosed with bilat-eral hearing loss. While they found a reduction in activity inthe auditory and language systems and an increase in visualand frontal cortical areas, the use of HA over one yearincrease the activity in the auditory and language cortices aswell as multimodal integration areas. Moreover, they foundan increased cortical thickness in multimodal integrationareas, particularly the very caudal end of the superior tempo-ral sulcus, the angular gyrus, and the insula. P. ÁlvarezMerino et al. (“Evidence Linking Brain Activity Modulationto Age and to Deductive Training”) investigated the effectof deductive reasoning training on modulation of electricbrain activity and compared this modulation between youn-ger (mean age 21 ± 3 39 years) and older (mean age 68 92± 5 72 years) healthy adults. While younger adults showedsymmetric bilateral activity in anterior brain areas in theirstudy, older adults showed asymmetrical activity in anteriorand posterior brain areas. They conclude that bilateral brainactivity modulation may be an age-dependent mechanismsto maintain cognitive function under high demand.

To better understand the role of serotonergic receptorsfor functional recovery after SCI, K. Miazga et al. analyzedthe mRNA of serotonergic 5-HT2A and 5-HT7 receptors(encoded by Htr2a and Htr7 genes) in motoneurons of ratswith and without SCI (“Intraspinal Grafting of SerotonergicNeurons Modifies Expression of Genes Important for Func-tional Recovery in Paraplegic Rats”). They found thatintraspinal grafting of serotonergic neurons can modify theexpression of Htr2a and Htr7 genes suggesting that upregula-tion of these genes might account for the improved locomo-tion found after intraspinal grafting.

Based on a number of studies suggesting a neuroprotec-tive effect of green tea (Camellia sinensis), P. M. Sosa et al.investigated whether green tea and red tea have a compara-ble effect on motor deficits and striatum oxidative damagein rats with hemorrhagic stroke (“Green Tea and Red Teafrom Camellia sinensis Partially Prevented the Motor Deficitsand Striatal Oxidative Damage Induced by HemorrhagicStroke in Rats”). They found that the two teas seemedequally effective.

M S. Sherwood et al. evaluated resting cerebral perfusionbefore and after transcranial direct current stimulation(tDCS), a form of transcranial electric stimulation (tES),applied to the left prefrontal cortex to investigate theunderlying neural mechanisms of tDCS on cognitive brainfunctions (“Repetitive Transcranial Electrical StimulationInduces Quantified Changes in Resting Cerebral PerfusionMeasured from Arterial Spin Labeling”). They found thattDCS increased cerebral perfusion across many areas ofthe brain as compared to sham stimulation. As this effectoriginated in the locus coeruleus linked to the noradrener-gic system, the authors suggest that the broad behavioral

effects of frontal lobe tDCS might relate to a modulation ofthe locus coeruleus that excites the noradrenergic system.

S. Betti et al. (“Testing rTMS-Induced Neuroplasticity: ASingle Case Study of Focal Hand Dystonia”) used 1Hzrepetitive transcranial magnetic stimulation (rTMS) target-ing the left primary motor cortex (M1) of an individualdiagnosed with focal hand dystonia. rTMS was applied overfive daily thirty-minute sessions. Using a fine-grained kine-matic analysis, they found that rTMS resulted in improvedmotor coordination, a finding that underlines the impor-tance of adopting measures that are sufficiently sensitive todetect behavioral improvements.

Only recently, novel neurotechnological tools, suchas brain/neural-machine interfaces (B/NMI) [10–14] orclosed-loop brain and spinal cord stimulation [15], weredeveloped that provide promising means to modulate CNSplasticity triggering neural recovery. A remarkable demon-stration of these new targeted neurotechnologies was recentlyprovided by Wagner et al. [16] demonstrating restoration ofwalking in individuals who sustained a spinal cord injury sev-eral years ago with permanent motor deficits despite exten-sive rehabilitation efforts. A few months of individualizedspatiotemporal electrical stimulation of the lumbosacral spi-nal cord resulted in regained voluntary control over previ-ously paralyzed muscles, even in the absence of stimulation.

As our understanding of the underlying mechanisms ofneural recovery improves and neurotechnologies advance,more of such demonstrations will be ahead of us. We hopethat this special issue will contribute towards such improvedunderstanding of the relationship between neural plasticityand functional recovery and will give new impulses on howneurorehabilitation can be advanced through neurotechno-logical tools.

Conflicts of Interest

The guest editors declare that there is no conflict of interest.

Toshiyuki FujiwaraJunichi Ushiba

Surjo R. Soekadar

References

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2 Neural Plasticity

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[9] E. Taub, N. E. Miller, T. A. Novack et al., “Technique toimprove chronic motor deficit after stroke,” Archives of Physi-cal Medicine and Rehabilitation, vol. 74, no. 4, pp. 347–354,1993.

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