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Brain functions are supported by multiple cell types, including neuronal and non-neuronal cells that are connected into complex networks. When the connectivity between those cells is altered or disrupted, the functioning of the brain is impaired. In stroke, the interruption of blood supply to the neural circuits results in connectivity damage and permanent disabilities. Experimental evidence suggests that some types of brain state, including sleep, can protect brain tissue from stroke and "repair" the damaged circuits. This project will investigate the neuronal mechanism underlying the protective effect of sleep on brain connectivity and network activity. To this end, the investigators will use a collection of state-of-the-art technologies including high-density electroencephalography (hd-EEG), transcranial magnetic stimulation (TMS) and transcranial alternating current stimulation (tACS). Perspectives include a better understanding of the causes and consequences of the perturbed electrical activity of the brain during sleep in stroke patients.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| TMS | Experimental | Real transcranial magnetic stimulation (TMS). |
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| sham TMS | Sham Comparator | Sham transcranial magnetic stimulation (TMS) as a comparison. |
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| TMS and tACS | Experimental | Real transcranial magnetic stimulation (TMS) and real transcranial alternating current stimulation (tACS). |
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| TMS and sham tACS | Sham Comparator | Real transcranial magnetic stimulation (TMS) and sham transcranial alternating current stimulation (tACS) as a comparison. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Transcranial Magnetic Stimulation (TMS) | Device | The investigators recently showed that the repeated application of the so-called continuous theta burst protocol (cTBS) over the contralesional hemisphere resulted in a long-standing improvement of visual hemineglect (Cazzoli et al., 2012). The cTBS protocol was developed by Huang et al. (Huang et al., 2005) and modified by the investigators' group (Nyffeler et al., 2006). TBS protocol consists of a burst of 3 pulses at a frequency of 30 Hz, repeated at 6 Hz. One continuous train includes 801 pulses, the duration of one cTBS train is 44 seconds. |
| Measure | Description | Time Frame |
|---|---|---|
| Change from baseline in visual exploration and sleep parameters and the effect of cTBS | Relationship of visual exploration (mean cumulative fixation duration) to sleep parameters (slow wave activity and spindles) from the baseline to post-cTBS sleep. | Day 3 |
| Change from baseline in the effect of tACS on visual exploration | Group comparison of visual exploration task (mean cumulative fixation duration) between real and sham tACS. | Day 2 |
| Measure | Description | Time Frame |
|---|---|---|
| The effect of cTBS on sleep | Relationship between baseline sleep parameters (slow wave activity and spindles) and effectiveness of cTBS. | Day 1 to 3 |
| The effect of tACS on sleep | Change in sleep architecture (REM and NREM sleep) between tACS and sham stimulation. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Claudio L. Bassetti, Prof. Dr. med. | Department of Neurology, Inselspital, Bern University Hospital | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Department of Neurology, Inselspital, Bern University Hospital | Bern | 3010 | Switzerland |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 15664172 | Background | Huang YZ, Edwards MJ, Rounis E, Bhatia KP, Rothwell JC. Theta burst stimulation of the human motor cortex. Neuron. 2005 Jan 20;45(2):201-6. doi: 10.1016/j.neuron.2004.12.033. | |
| 17049743 | Background | Nyffeler T, Wurtz P, Luscher HR, Hess CW, Senn W, Pflugshaupt T, von Wartburg R, Luthi M, Muri RM. Repetitive TMS over the human oculomotor cortex: comparison of 1-Hz and theta burst stimulation. Neurosci Lett. 2006 Nov 27;409(1):57-60. doi: 10.1016/j.neulet.2006.09.011. Epub 2006 Oct 17. |
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| Transcranial Alternating Current Stimulation (tACS) | Device | TACS stimulation involves two electrodes placed on either side of the desired site of cortical stimulation. The mode of stimulation used in this experiment is identical to previous studies using tACS in sleep ( Marshall et al., 2006; Prehn-Kristensen et al., 2014 ). Stimulation follows a sinusoidal pattern from 0 to 260 μA. This pattern is delivered at 0.75 Hz and is repeated for 225 cycles; a total of 5 minutes of stimulation. This 5 minute pattern is again repeated 5 times, with a minute of no stimulation between each; thus for a total of 30 minutes. |
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| sham Transcranial Magnetic Stimulation (TMS) | Device | Sham coil will be used to exclude possible nonspecific effects of the TMS. The sham coil is shielded i.e., the magnetic field output is weakened and therefore insufficiently powerful to stimulate the cortex. |
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| sham Transcranial Alternating Current Stimulation (tACS) | Device | Sham stimulation will be used to exclude possible nonspecific effects of the tACS. Sham tACS stimulation will involve actual stimulation for the first 30 seconds of the ramp-up period (stimulation power is gradually increased until its final level), and then immediately gradually decreased until zero (without the intermediate 4 minutes of actual stimulation). This procedure will be repeated 5 times every 6 minutes and shall induce similar cutaneous sensations as real stimulation. |
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| Day 1 to 2 |
| 22831781 | Result | Cazzoli D, Muri RM, Schumacher R, von Arx S, Chaves S, Gutbrod K, Bohlhalter S, Bauer D, Vanbellingen T, Bertschi M, Kipfer S, Rosenthal CR, Kennard C, Bassetti CL, Nyffeler T. Theta burst stimulation reduces disability during the activities of daily living in spatial neglect. Brain. 2012 Nov;135(Pt 11):3426-39. doi: 10.1093/brain/aws182. Epub 2012 Jul 24. |
| 17086200 | Result | Marshall L, Helgadottir H, Molle M, Born J. Boosting slow oscillations during sleep potentiates memory. Nature. 2006 Nov 30;444(7119):610-3. doi: 10.1038/nature05278. Epub 2006 Nov 5. |
| ID | Term |
|---|---|
| D010468 | Perceptual Disorders |
| ID | Term |
|---|---|
| D019954 | Neurobehavioral Manifestations |
| D009461 | Neurologic Manifestations |
| D009422 | Nervous System Diseases |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| ID | Term |
|---|---|
| D050781 | Transcranial Magnetic Stimulation |
| D065908 | Transcranial Direct Current Stimulation |
| ID | Term |
|---|---|
| D055909 | Magnetic Field Therapy |
| D013812 | Therapeutics |
| D004599 | Electric Stimulation Therapy |
| D003295 | Convulsive Therapy |
| D013000 | Psychiatric Somatic Therapies |
| D004191 | Behavioral Disciplines and Activities |
| D004597 | Electroshock |
| D011580 | Psychological Techniques |
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