Abstract
Background
Task switching, defined as the ability to flexibly switch between tasks in the face
of goal shifting, is a central mechanism in cognitive control. Task switching is thought
to involve both prefrontal cortex (PFC) and parietal regions. Our previous work has
shown that it is possible to modulate set shifting tasks using 1 mA tDCS on both the
left dorsolateral prefrontal cortex and the left primary motor area. However, it remains
unclear whether the effects of PFC tDCS on task switching are hemisphere-dependent.
Objectives
We aimed to test the effects of three types of cross-hemispheric tDCS over the PFC
(left anode–right cathode [LA-RC], left cathode–right anode [LC-RA] and sham stimulation)
on participants' performance (reaction time) and accuracy (correct responses) in two
task-switching paradigms (i.e., letter/digit naming and vowel–consonant/parity tasks).
Methods
Sixteen participants received cross-hemispheric tDCS over the PFC in two task-switching
paradigms.
Results
The results show that cross-hemispheric tDCS over the PFC modulates task-switching
ability in both paradigms. Our results were task and hemisphere-specific, such that
in the letter/digit naming task, LA-RC tDCS increased switching performance, whereas
LC-RA tDCS improved accuracy. On the other hand, in the vowel–consonant/parity task,
LA-RC improved accuracy, and decreased switching performance.
Conclusions
Our findings confirm the notion that involvement of the PFC on task switching depends
critically on laterality, implying the existence of different roles for the left hemisphere
and the right hemisphere in task switching.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Brain Stimulation: Basic, Translational, and Clinical Research in NeuromodulationAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Decomposing components of task preparation with functional magnetic resonance imaging.J Cogn Neurosci. 2004; 16: 609-620
- Task switching.Trends Cogn Sci. 2003; 7: 134-140
- Dissociating the roles of the rostral anterior cingulate and the lateral prefrontal cortices in performing two tasks simultaneously or successively.Cereb Cortex. 2003; 13: 329-339
- Dissociable mechanisms of attentional control within the human prefrontal cortex.Cereb Cortex. 2001; 11: 85-92
- Shifting set about task switching: behavioral and neural evidence for distinct forms of cognitive flexibility.Neuropsychologia. 2008; 46: 2924-2935
- Cognitive control involved in overcoming prepotent response tendencies and switching between tasks.Cereb Cortex. 2005; 15: 899-912
- A componential analysis of task-switching deficits associated with lesions of left and right frontal cortex.Brain. 2004; 127: 1561-1573
- The role of prefrontal cortex and posterior parietal cortex in task switching.Proc Natl Acad Sci U S A. 2000; 97: 13448-13453
- Task-specific effects of tDCS-induced cortical excitability changes on cognitive and motor sequence set shifting performance.PLoS One. 2011; 6: e24140
- Is the prefrontal cortex necessary for delay task performance? Evidence from lesion and FMRI data.J Int Neuropsychol Soc. 2006; 12: 248-260
- Cerebral specialization and interhemispheric communication: does the corpus callosum enable the human condition?.Brain. 2000; 123: 1293-1326
- Dissociating the roles of right ventral lateral and dorsal lateral prefrontal cortex in generation and maintenance of hypotheses in set-shift problems.Cereb Cortex. 2005; 15: 1170-1177
- Hemispheric specialization in human prefrontal cortex for resolving certain and uncertain inferences.Cereb Cortex. 2007; 17: 2245-2250
- Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory.Exp Brain Res. 2005; 166: 23-30
- The roles of prefrontal brain regions in components of working memory: effects of memory load and individual differences.Proc Natl Acad Sci U S A. 1999; 96: 6558-6563
- Sustained excitability elevations induced by transcranial DC motor cortex stimulation in humans.Neurology. 2001; 57: 1899-1901
- Non-synaptic mechanisms underlie the after-effects of cathodal transcutaneous direct current stimulation of the human brain.J Physiol. 2005; 568: 653-663
- Temporal lobe cortical electrical stimulation during the encoding and retrieval phase reduces false memories.PLoS One. 2009; 4: e4959
- Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation.J Physiol. 2000; 527: 633-639
- The ten-twenty electrode system of the International Federation.Electroencephalogr Clin Neurophysiol Suppl. 1958; 10: 371-375
- Oscillations in the alpha band (9–12 Hz) increase with memory load during retention in a short-term memory task.Cereb Cortex. 2002; 12: 877-882
- Transcranial direct current stimulation facilitates decision making in a probabilistic guessing task.J Neurosci. 2010; 30: 4241-4245
- Diminishing risk-taking behavior by modulating activity in the prefrontal cortex: a direct current stimulation study.J Neurosci. 2007; 27: 12500-12505
- Transcranial direct current stimulation of the prefrontal cortex modulates the desire for specific foods.Appetite. 2008; 51: 34-41
- Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: a double-blind, sham-controlled study.Drug Alcohol Depend. 2008; 92: 55-60
- The left hemisphere's role in hypothesis formation.J Neurosci. 2000; 20: RC64
- Hemispheric asymmetries: a brain in two minds.Curr Biol. 2000; 10: R460-R462
- Transcranial direct current stimulation: a computer-based human model study.NeuroImage. 2007; 35: 1113-1124
- Modeling the current distribution during transcranial direct current stimulation.Clin Neurophysiol. 2006; 117: 1623-1629
- Inhibition and the right inferior frontal cortex.Trends Cogn Sci. 2004; 8: 170-177
- Activation of inhibition: diminishing impulsive behavior by direct current stimulation over the inferior frontal gyrus.J Cogn Neurosci. 2011; 23: 3380-3387
- Space and the parietal cortex.Trends Cogn Sci. 2007; 11: 30-36
- The reorienting system of the human brain: from environment to theory of mind.Neuron. 2008; 58: 306-324
- Decoding sequential stages of task preparation in the human brain.NeuroImage. 2009; 45: 606-613
- Transcranial direct current stimulation modulates shifts in global/local attention.NeuroReport. 2009; 20: 1115-1119
- Neuronal signal dynamics during preparation and execution for behavioral shifting in macaque posterior parietal cortex.J Cogn Neurosci. 2011; 23: 2503-2520
- Dissociable prefrontal brain systems for attention and emotion.Proc Natl Acad Sci U S A. 2002; 99: 11447-11451
- Switching between simple cognitive tasks: the interaction of top-down and bottom-up factors.J Exp Psychol Hum Percept Perform. 2001; 27: 1404-1419
- Executive control of cognitive processes in task switching.J Exp Psychol Hum Percept Perform. 2001; 27: 763-797
Article info
Publication history
Published online: November 05, 2012
Accepted:
October 14,
2012
Received in revised form:
September 21,
2012
Received:
February 11,
2012
Footnotes
Author's notes: Special authorship status—Jorge Leite and Sandra Carvalho share co-first authorship.
This work was supported by the Portuguese Foundation for Science and Technology with individual grants (SFRH/BD/41484/2007 and SFRH/BD/64355/2009).
Conflict of interest: The authors do not have any conflicts of interest, financial or otherwise, to disclose.
Identification
Copyright
© 2013 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
