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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

Experimental design: the figure illustrates the sequence of events in each trial.
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Figure 1: Experimental design: the figure illustrates the sequence of events in each trial.

Mentions: The procedure of the experimental sessions was carried out sequentially: the participants performed a delayed matching-to-sample visuo-spatial WM task (Vogel and Machizawa, 2004) with concurrent EEG recording starting 7.4 min ± 2.4 (SD) after each tDCS condition (sham, anodal, cathodal). Stimulus presentation was controlled by the Presentation software (Neurobehavioral Systems, USA). During each trial, subjects were presented a fixation cross (2800 ± 3500 ms) followed by an arrow (200 ms) indicating the hemifield (left/right) to be attended. A memory array was then presented within two rectangular regions that were centered to the left and right on a gray background. These two rectangular regions of the memory arrays consisted of four colored circles (0.69°) with randomized position (within a rectangle) and were randomly colored (blue, brown, green, red, cyan, yellow, orange, pink, black, white). The memory array appeared for 150 ms and was followed by a retention period of 2000 ms during which subjects had to retain the memory array. This was followed by the presentation of a test array with one circle in the center of the screen, which was either identical or different in color compared to the circles shown in the memory array (cf. Figure 1). Subjects had 2000 ms before the onset of the next trial to make a push-button response to indicate whether or not the probe stimulus in the test array was identical to one stimulus in the memory array. The test sequence consisted of 256 trials separated into four runs. The order of the trials was identical across individual sessions but pseudo randomized across subject.


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)

Experimental design: the figure illustrates the sequence of events in each trial.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Experimental design: the figure illustrates the sequence of events in each trial.
Mentions: The procedure of the experimental sessions was carried out sequentially: the participants performed a delayed matching-to-sample visuo-spatial WM task (Vogel and Machizawa, 2004) with concurrent EEG recording starting 7.4 min ± 2.4 (SD) after each tDCS condition (sham, anodal, cathodal). Stimulus presentation was controlled by the Presentation software (Neurobehavioral Systems, USA). During each trial, subjects were presented a fixation cross (2800 ± 3500 ms) followed by an arrow (200 ms) indicating the hemifield (left/right) to be attended. A memory array was then presented within two rectangular regions that were centered to the left and right on a gray background. These two rectangular regions of the memory arrays consisted of four colored circles (0.69°) with randomized position (within a rectangle) and were randomly colored (blue, brown, green, red, cyan, yellow, orange, pink, black, white). The memory array appeared for 150 ms and was followed by a retention period of 2000 ms during which subjects had to retain the memory array. This was followed by the presentation of a test array with one circle in the center of the screen, which was either identical or different in color compared to the circles shown in the memory array (cf. Figure 1). Subjects had 2000 ms before the onset of the next trial to make a push-button response to indicate whether or not the probe stimulus in the test array was identical to one stimulus in the memory array. The test sequence consisted of 256 trials separated into four runs. The order of the trials was identical across individual sessions but pseudo randomized across subject.

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