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Modulating pathological oscillations by rhythmic non-invasive brain stimulation-a therapeutic concept?

Krawinkel LA, Engel AK, Hummel FC - Front Syst Neurosci (2015)

Bottom Line: Alike, abnormalities of oscillatory activity were related with pathological behavior in many neuropsychiatric disorders, such as in Parkinson's disease (PD) or in schizophrenia (SCZ).In particular, we will review oscillatory changes described in patients after stroke, with PD or suffering from SCZ.Potential ways of targeting interventionally the underlying pathological oscillations to improve related pathological behavior will be further discussed.

View Article: PubMed Central - PubMed

Affiliation: BrainImaging and NeuroStimulation (BINS) Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany.

ABSTRACT
A large amount of studies of the last decades revealed an association between human behavior and oscillatory activity in the human brain. Alike, abnormalities of oscillatory activity were related with pathological behavior in many neuropsychiatric disorders, such as in Parkinson's disease (PD) or in schizophrenia (SCZ). As a therapeutic tool, non-invasive brain stimulation (NIBS) has demonstrated the potential to improve behavioral performance in patients suffering from neuropsychiatric disorders. Since evidence accumulates that NIBS might be able to modulate oscillatory activity and related behavior in a scientific setting, this review focuses on discussing potential interventional strategies to target abnormalities in oscillatory activity in neuropsychiatric disorders. In particular, we will review oscillatory changes described in patients after stroke, with PD or suffering from SCZ. Potential ways of targeting interventionally the underlying pathological oscillations to improve related pathological behavior will be further discussed.

No MeSH data available.


Related in: MedlinePlus

(A) Schematic: Bifocal repetitive TMS (rTMS) restores alpha-band activity. After stroke, alpha oscillators (red line, left) of the affected area (red X, primary motor cortex) show unsteady phase properties. Since physiological behavior depends on a constant phase relation of alpha oscillations between the affected area and connected networks (blue O, blue line, left, premotor areas), the patient is impaired (behavior, left, e.g., muscle contractions). After application of bifocal, rTMS at alpha frequency over both areas with a lag reflecting physiological offset of oscillators, oscillatory activity is synchronized (blue and red line, right) in terms of a constant phase lag. Behavior improves (right). Please note that conditions are highly simplified. First, next to phase, also amplitude is important for signal processing. Second, in the presented physiological condition (right) phases are completely locked, which is artificial. Naturally, phases would fluctuate. (B) Schematic: tRNS augments alpha oscillators. After stroke alpha activity (red line, left) of the affected area (red X) is reduced. Threshold for establishing information processing with a related network (blue line, left) is not reached and dependent normal behavior is reduced. tRNS applied over the affected oscillator augments alpha activity by adding noise (red line, right). Information processing is re-established and behavior improves. Please note that conditions are very much simplified. In both cases, phase is totally locked without any phase lag. Biological signals would fluctuate.
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Figure 1: (A) Schematic: Bifocal repetitive TMS (rTMS) restores alpha-band activity. After stroke, alpha oscillators (red line, left) of the affected area (red X, primary motor cortex) show unsteady phase properties. Since physiological behavior depends on a constant phase relation of alpha oscillations between the affected area and connected networks (blue O, blue line, left, premotor areas), the patient is impaired (behavior, left, e.g., muscle contractions). After application of bifocal, rTMS at alpha frequency over both areas with a lag reflecting physiological offset of oscillators, oscillatory activity is synchronized (blue and red line, right) in terms of a constant phase lag. Behavior improves (right). Please note that conditions are highly simplified. First, next to phase, also amplitude is important for signal processing. Second, in the presented physiological condition (right) phases are completely locked, which is artificial. Naturally, phases would fluctuate. (B) Schematic: tRNS augments alpha oscillators. After stroke alpha activity (red line, left) of the affected area (red X) is reduced. Threshold for establishing information processing with a related network (blue line, left) is not reached and dependent normal behavior is reduced. tRNS applied over the affected oscillator augments alpha activity by adding noise (red line, right). Information processing is re-established and behavior improves. Please note that conditions are very much simplified. In both cases, phase is totally locked without any phase lag. Biological signals would fluctuate.

Mentions: Based on the emerging understanding about the relationship between NIBS and the modulation or induction of oscillatory activity in the last decad, hypotheses on how to enhance brain functioning and ameliorate impaired behavior after focal brain lesions can be defined. These hypotheses would be amenable to evaluation in controlled clinical trials in stroke patients. Combining the evidence that (1) changes in alpha-band activity are correlated with recovery and performance after stroke (Dubovik et al., 2012; Westlake et al., 2012) and that (2) NIBS is able modulate alpha-band activity (Plewnia et al., 2008; Thut et al., 2011) one could consider applying rhythmic alpha-NIBS after stroke. As illustrated schematically in Figure 1A, bifocal TMS at alpha frequency could entrain alpha-band activity between lesioned areas and relevant neighboring regions. In this context, bifocal application should potentially be performed with a certain phase lag between the targeted areas. An application of less focal alpha tACS in a montage covering both targeted areas would be another option. In both cases rhythmic NIBS would potentially lead to a synchronization in the alpha-band of lesioned sites and relevant connected areas like ipsilateral and contralateral premotor cortices respectively (Johansen-Berg et al., 2002; Ward et al., 2003; Gerloff et al., 2006; Rehme et al., 2011; Dubovik et al., 2012; Westlake et al., 2012).


Modulating pathological oscillations by rhythmic non-invasive brain stimulation-a therapeutic concept?

Krawinkel LA, Engel AK, Hummel FC - Front Syst Neurosci (2015)

(A) Schematic: Bifocal repetitive TMS (rTMS) restores alpha-band activity. After stroke, alpha oscillators (red line, left) of the affected area (red X, primary motor cortex) show unsteady phase properties. Since physiological behavior depends on a constant phase relation of alpha oscillations between the affected area and connected networks (blue O, blue line, left, premotor areas), the patient is impaired (behavior, left, e.g., muscle contractions). After application of bifocal, rTMS at alpha frequency over both areas with a lag reflecting physiological offset of oscillators, oscillatory activity is synchronized (blue and red line, right) in terms of a constant phase lag. Behavior improves (right). Please note that conditions are highly simplified. First, next to phase, also amplitude is important for signal processing. Second, in the presented physiological condition (right) phases are completely locked, which is artificial. Naturally, phases would fluctuate. (B) Schematic: tRNS augments alpha oscillators. After stroke alpha activity (red line, left) of the affected area (red X) is reduced. Threshold for establishing information processing with a related network (blue line, left) is not reached and dependent normal behavior is reduced. tRNS applied over the affected oscillator augments alpha activity by adding noise (red line, right). Information processing is re-established and behavior improves. Please note that conditions are very much simplified. In both cases, phase is totally locked without any phase lag. Biological signals would fluctuate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4362311&req=5

Figure 1: (A) Schematic: Bifocal repetitive TMS (rTMS) restores alpha-band activity. After stroke, alpha oscillators (red line, left) of the affected area (red X, primary motor cortex) show unsteady phase properties. Since physiological behavior depends on a constant phase relation of alpha oscillations between the affected area and connected networks (blue O, blue line, left, premotor areas), the patient is impaired (behavior, left, e.g., muscle contractions). After application of bifocal, rTMS at alpha frequency over both areas with a lag reflecting physiological offset of oscillators, oscillatory activity is synchronized (blue and red line, right) in terms of a constant phase lag. Behavior improves (right). Please note that conditions are highly simplified. First, next to phase, also amplitude is important for signal processing. Second, in the presented physiological condition (right) phases are completely locked, which is artificial. Naturally, phases would fluctuate. (B) Schematic: tRNS augments alpha oscillators. After stroke alpha activity (red line, left) of the affected area (red X) is reduced. Threshold for establishing information processing with a related network (blue line, left) is not reached and dependent normal behavior is reduced. tRNS applied over the affected oscillator augments alpha activity by adding noise (red line, right). Information processing is re-established and behavior improves. Please note that conditions are very much simplified. In both cases, phase is totally locked without any phase lag. Biological signals would fluctuate.
Mentions: Based on the emerging understanding about the relationship between NIBS and the modulation or induction of oscillatory activity in the last decad, hypotheses on how to enhance brain functioning and ameliorate impaired behavior after focal brain lesions can be defined. These hypotheses would be amenable to evaluation in controlled clinical trials in stroke patients. Combining the evidence that (1) changes in alpha-band activity are correlated with recovery and performance after stroke (Dubovik et al., 2012; Westlake et al., 2012) and that (2) NIBS is able modulate alpha-band activity (Plewnia et al., 2008; Thut et al., 2011) one could consider applying rhythmic alpha-NIBS after stroke. As illustrated schematically in Figure 1A, bifocal TMS at alpha frequency could entrain alpha-band activity between lesioned areas and relevant neighboring regions. In this context, bifocal application should potentially be performed with a certain phase lag between the targeted areas. An application of less focal alpha tACS in a montage covering both targeted areas would be another option. In both cases rhythmic NIBS would potentially lead to a synchronization in the alpha-band of lesioned sites and relevant connected areas like ipsilateral and contralateral premotor cortices respectively (Johansen-Berg et al., 2002; Ward et al., 2003; Gerloff et al., 2006; Rehme et al., 2011; Dubovik et al., 2012; Westlake et al., 2012).

Bottom Line: Alike, abnormalities of oscillatory activity were related with pathological behavior in many neuropsychiatric disorders, such as in Parkinson's disease (PD) or in schizophrenia (SCZ).In particular, we will review oscillatory changes described in patients after stroke, with PD or suffering from SCZ.Potential ways of targeting interventionally the underlying pathological oscillations to improve related pathological behavior will be further discussed.

View Article: PubMed Central - PubMed

Affiliation: BrainImaging and NeuroStimulation (BINS) Laboratory, Department of Neurology, University Medical Center Hamburg-Eppendorf Hamburg, Germany.

ABSTRACT
A large amount of studies of the last decades revealed an association between human behavior and oscillatory activity in the human brain. Alike, abnormalities of oscillatory activity were related with pathological behavior in many neuropsychiatric disorders, such as in Parkinson's disease (PD) or in schizophrenia (SCZ). As a therapeutic tool, non-invasive brain stimulation (NIBS) has demonstrated the potential to improve behavioral performance in patients suffering from neuropsychiatric disorders. Since evidence accumulates that NIBS might be able to modulate oscillatory activity and related behavior in a scientific setting, this review focuses on discussing potential interventional strategies to target abnormalities in oscillatory activity in neuropsychiatric disorders. In particular, we will review oscillatory changes described in patients after stroke, with PD or suffering from SCZ. Potential ways of targeting interventionally the underlying pathological oscillations to improve related pathological behavior will be further discussed.

No MeSH data available.


Related in: MedlinePlus