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Behavioral and electrophysiological effects of transcranial direct current stimulation of the parietal cortex in a visuo-spatial working memory task.

Heimrath K, Sandmann P, Becke A, Müller NG, Zaehle T - Front Psychiatry (2012)

Bottom Line: The results showed that tDCS modulated WM performance and its underlying electrophysiological brain activity in a polarity-specific way.This result can be considered an important step toward a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing.This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.

View Article: PubMed Central - PubMed

Affiliation: Section of Neuropsychology, Department of Neurology, Otto-von-Guericke University Magdeburg Magdeburg, Germany.

ABSTRACT
Impairments of working memory (WM) performance are frequent concomitant symptoms in several psychiatric and neurologic diseases. Despite the great advance in treating the reduced WM abilities in patients suffering from, e.g., Parkinson's and Alzheimer's disease by means of transcranial direct current stimulation (tDCS), the exact neurophysiological underpinning subserving these therapeutic tDCS-effects are still unknown. In the present study we investigated the impact of tDCS on performance in a visuo-spatial WM task and its underlying neural activity. In three experimental sessions, participants performed a delayed matching-to-sample WM task after sham, anodal, and cathodal tDCS over the right parietal cortex. The results showed that tDCS modulated WM performance and its underlying electrophysiological brain activity in a polarity-specific way. Parietal tDCS altered event-related potentials and oscillatory power in the alpha band at posterior electrode sites. The present study demonstrates that posterior tDCS can alter visuo-spatial WM performance by modulating the underlying neural activity. This result can be considered an important step toward a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing. This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.

No MeSH data available.


Related in: MedlinePlus

Transcranial direct current stimulation effect on working memory capacity K: WM capacity (K) is given for sham (blue), anodal (red), and cathodal (green) tDCS of the right parietal cortex separately for attended stimuli in the left and right hemifield.
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Figure 2: Transcranial direct current stimulation effect on working memory capacity K: WM capacity (K) is given for sham (blue), anodal (red), and cathodal (green) tDCS of the right parietal cortex separately for attended stimuli in the left and right hemifield.

Mentions: The K value (Cowan, 2001), an individual estimate of WM capacity, was calculated for each subject separately for each tDCS condition (cf. Figure 2). The 3 × 2 repeated-measures ANOVA with the factors tDCS (sham, anodal, cathodal) and hemifield (left, right) revealed a significant tDCS × hemifield interaction [F(1.8, 20.4) = 4.16, P < 0.05]. Neither the main effect for factor tDCS [sham, anodal, cathodal; F(1.9, 21.6) = 2.12, P = 0.15] nor the main effect for factor hemifield [left, right; F(1.11) = 0.54; P = 0.48] reached statistical significance. Subsequent separate ANOVAs with the factor tDCS (sham, anodal, cathodal) for the left and right hemifield revealed a significant main effect of tDCS for stimuli attended in the left hemifield only [F(1.8, 20.6) = 3.93, P < 0.05]. While anodal tDCS of the right parietal cortex decreased WM capacity for contralateral stimuli, cathodal tDCS increased it. For stimuli that had to be attended on the ipsilateral (right) hemifield, both active tDCS conditions interfered with the WM capacity in comparison to the sham condition.


Behavioral and electrophysiological effects of transcranial direct current stimulation of the parietal cortex in a visuo-spatial working memory task.

Heimrath K, Sandmann P, Becke A, Müller NG, Zaehle T - Front Psychiatry (2012)

Transcranial direct current stimulation effect on working memory capacity K: WM capacity (K) is given for sham (blue), anodal (red), and cathodal (green) tDCS of the right parietal cortex separately for attended stimuli in the left and right hemifield.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3378949&req=5

Figure 2: Transcranial direct current stimulation effect on working memory capacity K: WM capacity (K) is given for sham (blue), anodal (red), and cathodal (green) tDCS of the right parietal cortex separately for attended stimuli in the left and right hemifield.
Mentions: The K value (Cowan, 2001), an individual estimate of WM capacity, was calculated for each subject separately for each tDCS condition (cf. Figure 2). The 3 × 2 repeated-measures ANOVA with the factors tDCS (sham, anodal, cathodal) and hemifield (left, right) revealed a significant tDCS × hemifield interaction [F(1.8, 20.4) = 4.16, P < 0.05]. Neither the main effect for factor tDCS [sham, anodal, cathodal; F(1.9, 21.6) = 2.12, P = 0.15] nor the main effect for factor hemifield [left, right; F(1.11) = 0.54; P = 0.48] reached statistical significance. Subsequent separate ANOVAs with the factor tDCS (sham, anodal, cathodal) for the left and right hemifield revealed a significant main effect of tDCS for stimuli attended in the left hemifield only [F(1.8, 20.6) = 3.93, P < 0.05]. While anodal tDCS of the right parietal cortex decreased WM capacity for contralateral stimuli, cathodal tDCS increased it. For stimuli that had to be attended on the ipsilateral (right) hemifield, both active tDCS conditions interfered with the WM capacity in comparison to the sham condition.

Bottom Line: The results showed that tDCS modulated WM performance and its underlying electrophysiological brain activity in a polarity-specific way.This result can be considered an important step toward a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing.This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.

View Article: PubMed Central - PubMed

Affiliation: Section of Neuropsychology, Department of Neurology, Otto-von-Guericke University Magdeburg Magdeburg, Germany.

ABSTRACT
Impairments of working memory (WM) performance are frequent concomitant symptoms in several psychiatric and neurologic diseases. Despite the great advance in treating the reduced WM abilities in patients suffering from, e.g., Parkinson's and Alzheimer's disease by means of transcranial direct current stimulation (tDCS), the exact neurophysiological underpinning subserving these therapeutic tDCS-effects are still unknown. In the present study we investigated the impact of tDCS on performance in a visuo-spatial WM task and its underlying neural activity. In three experimental sessions, participants performed a delayed matching-to-sample WM task after sham, anodal, and cathodal tDCS over the right parietal cortex. The results showed that tDCS modulated WM performance and its underlying electrophysiological brain activity in a polarity-specific way. Parietal tDCS altered event-related potentials and oscillatory power in the alpha band at posterior electrode sites. The present study demonstrates that posterior tDCS can alter visuo-spatial WM performance by modulating the underlying neural activity. This result can be considered an important step toward a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing. This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.

No MeSH data available.


Related in: MedlinePlus