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Sukhvinder S. Obhi, Patrick Haggard, John Taylor, and Alvaro Pascual-Leone

Bimanual coordination tasks form an essential part of our behaviour. One brain region thought to be involved in bimanual coordination is the supplementary motor area (SMA). We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz for 5 min to create a temporary virtual lesion of the rostral portion of the human SMA immediately prior to performance of a goal-directed bimanual coordination task. In two control conditions, participants underwent sham stimulation or stimulation over the primary motor cortex (MI). The experimental task was to open a drawer with the left hand, catch a ball with the right hand, and reinsert the ball into the drawer through an aperture just big enough for the ball to pass through, again with the right hand. Hence, the actions of one hand depend upon the actions of the other. We calculated time intervals between the successive component actions of one hand (unimanual intervals) and actions of both hands (bimanual intervals) and analyzed these intervals separately. Interestingly, none of the unimanual intervals were affected by the rTMS, but the variability of a critical bimanual interval—the time between the left hand opening the drawer and the right hand starting to move to catch the ball—was increased by rTMS over the rostral parts of the SMA. No such effect was seen following rTMS over MI or after sham rTMS. Our results suggest that the rostral parts of the SMA play an important role in aspects of functional bimanual tasks, which involve tight temporal coordination between different motor actions of the two hands.

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Carsten Eggers, Ulrike Grüner, Mitra Ameli, Anna-Sophia Sarfeld, and Dennis A. Nowak

This study investigated whether a period of low frequency rTMS preconditioned by tDCS over the primary motor cortex modulates control of grip force in Parkinson’s disease. The presented results are from the same patient cohort tested in an earlier study (Gruner et al. J Neural Transm 2010: 117: 207–216). 15 patients with Parkinson’s disease (mean age: 69 ±8 years; average disease duration: 5 ±3 years) on dopaminergic drugs performed a grasp-lift task with either hand before (baseline) and after a period of 1Hz rTMS (90% of the resting motor threshold; 900 pulses) preconditioned by sham, anodal or cathodal tDCS (1mA, 10 min) over the primary motor cortex. We found that compared with baseline, none of the grip force parameters was significantly influenced by either stimulation session and concluded that grasping is a higher order motor skill, which cannot be modulated by tDCS preconditioned 1Hz rTMS in PD.

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Robert Chen and Kaviraja Udupa

Several techniques that involve transcranial magnetic stimulation (TMS) can be used to measure brain plasticity noninvasively in humans. These include paired-associative stimulation (PAS), repetitive transcranial magnetic stimulation (rTMS) and theta burst stimulation (TBS). Some of these techniques are based the principle of use dependent plasticity or are designed to mimic protocols used to induce long-term potentiation or depression in animal studies. These studies have been applied to certain neurological and psychiatric disorders to investigate their pathophysiology. For example, PAS induced plasticity is enhanced in dystonia and stroke but is reduced in Huntington’s disease and schizophrenia. Furthermore, TMS may be used to modulate brain plasticity and has therapeutic potential in neurological and psychiatric disorders such as stroke, Parkinson’s disease, dystonia and depression.

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Jumpei Mizuno, Masashi Kawamura, and Minoru Hoshiyama

perspectives (Figure  4 ) and tasks (Figure  5 ). The coherence value between cortices was affected by perspectives. The values in the θ range under the 1P-R condition were higher than Mirror-R between Lt-IPL and Rt-M1, F (2, 54) = 3.44, p  = .04, and Rt-PMv and Rt-S1, F (2, 54) = 3.46, p  = .04. In the α

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Andrew Hooyman, Alexander Garbin, and Beth Fisher

Background Modulation of Intracortical Connectivity Current non-invasive brain stimulation (NIBS) paradigms, Repetitive Transcranial Magnetic Stimulation (rTMS) and Transcranial Direct Current Stimulation (tDCS), focus on changing behaviors through up or down regulation of a single cortical region

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Xiaoyue Hu, Jingxian Li, and Lin Wang

, Y.Y . ( 2017 ). Female sex hormones modulate the response to low-frequency rTMS in the human motor cortex . Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 10 ( 4 ), 850 – 852 . doi:10.1016/j.brs.2017.02.010 10.1016/j.brs.2017.02.010 Romani , W. , Patrie

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Thorben Hülsdünker, Martin Ostermann, and Andreas Mierau

, 12 ( 11 ), 1068 – 1079 . 10.1093/ntr/ntq159 Schenk , T. , Ellison , A. , Rice , N. , & Milner , A.D. ( 2005 ). The role of V5/MT+ in the control of catching movements: An rTMS study . Neuropsychologia, 43 ( 2 ), 189 – 198 . PubMed ID: 15707904 doi:10.1016/j.neuropsychologia.2004