Abstract
Background
Transcranial electric stimulation (tES) protocols are able to induce neuromodulation,
offering important insights to focus and constrain theories of the relationship between
brain and behavior. Previous studies have shown that different types of tES (i.e.,
direct current stimulation – tDCS, and random noise stimulation – tRNS) induce different
facilitatory behavioral effects. However to date is not clear which is the optimal
timing to apply tES in relation to the induction of robust facilitatory effects.
Objective/hypothesis
The goal of this work was to investigate how different types of tES (tDCS and tRNS)
can modulate behavioral performance in the healthy adult brain in relation to their
timing of application. We applied tES protocols before (offline) or during (online)
the execution of a visual perceptual learning (PL) task. PL is a form of implicit
memory that is characterized by an improvement in sensory discrimination after repeated
exposure to a particular type of stimulus and is considered a manifestation of neural
plasticity. Our aim was to understand if the timing of tES is critical for the induction
of differential neuromodulatory effects in the primary visual cortex (V1).
Methods
We applied high-frequency tRNS, anodal tDCS and sham tDCS on V1 before or during the
execution of an orientation discrimination task. The experimental design was between
subjects and performance was measured in terms of d' values.
Results
The ideal timing of application varied depending on the stimulation type. tRNS facilitated
task performance only when it was applied during task execution, whereas anodal tDCS
induced a larger facilitation if it was applied before task execution.
Conclusion
The main result of this study is the finding that the timing of identical tES protocols
yields opposite effects on performance. These results provide important guidelines
for designing neuromodulation induction protocols and highlight the different optimal
timing of the two excitatory techniques.
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
- Transcranial direct current stimulation - update 2011.Restor Neurol Neurosci. 2011; 29: 463-492
- Transcranial electrical stimulation (tES - tDCS; tRNS, tACS) methods.Neuropsychol Rehabil. 2011; 21: 602-617
- Brain stimulation and behavioural cognitive rehabilitation: a new tool for neurorehabilitation?.Neuropsychol Rehabil. 2011; 21: 553-559
- Fahle M. Poggio T. Perceptual learning. MIT Press, Cambridge, Massachusetts2002
- The neural basis of perceptual learning.Neuron. 2001; 31: 681-697
- Perceptual learning and dynamic changes in primary visual cortex.Neuron. 2008; 57: 799-801
- Perceptual learning and top-down influences in primary visual cortex.Nat Neurosci. 2004; 7: 651-657
- Learning strengthens the response of primary visual cortex to simple patterns.Curr Biol. 2004; 14: 573-578
- A unified model for perceptual learning.Trends Cogn Sci. 2005; 9: 329-334
- Perceptual learning: is V1 up to the task?.Curr Biol. 2004; 14: R671-R673
- Random noise stimulation improves neuroplasticity in perceptual learning.J Neurosci. 2011; 31: 15416-15423
- Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation.J Physiol. 2000; 527: 633-639
- Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.Brain. 2002; 125: 2238-2247
- Increasing human brain excitability by transcranial high-frequency random noise stimulation.J Neurosci. 2008; 28: 14147-14155
- Physiological basis of transcranial direct current stimulation.Neuroscientist. 2011; 17: 37-53
- Facilitation of implicit motor learning by weak transcranial direct current stimulation of the primary motor cortex in the human.J Cogn Neurosci. 2003; 15: 619-626
- Sex differences in cortical neuroplasticity in humans.Neuroreport. 2006; 17: 1703-1707
- Behavioural facilitation following brain stimulation: implications for neurorehabilitation.Neuropsychol Rehabil. 2011; 21: 618-649
- Naming facilitation induced by transcranial direct current stimulation.Behav Brain Res. 2010; 208: 311-318
- Efficacy of repetitive transcranial magnetic stimulation/transcranial direct current stimulation in cognitive neurorehabilitation.Brain Stimul. 2008; 1: 326-336
- Safety aspects of transcranial direct current stimulation concerning healthy subjects and patients.Brain Res Bull. 2007; 72: 208-214
- Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research.Clin Neurophysiol. 2009; 120: 2008-2039
- Gender-specific modulation of short-term neuroplasticity in the visual cortex induced by transcranial direct current stimulation.Vis Neurosci. 2008; 25: 77-81
- Effects of ovarian hormones on human cortical excitability.Ann Neurol. 2002; 51: 599-603
- Menstrual cycle effects on cortical excitability.Neurology. 1999; 53: 2069-2072
- Ovarian hormones and cortical excitability. An rTMS study in humans.Clin Neurophysiol. 2004; 115: 1063-1068
- Factors influencing the magnitude and reproducibility of corticomotor excitability changes induced by paired associative stimulation.Exp Brain Res. 2007; 181: 615-626
- Perceptual learning on orientation and direction discrimination.Vis Res. 1999; 39: 3692-3701
- Retina or visual cortex? The site of phosphene induction by transcranial alternating current stimulation.Front Integr Neurosci. 2009; 3: 6
- Transcranial DC stimulation (tDCS): a tool for double-blind sham-controlled clinical studies in brain stimulation.Clin Neurophysiol. 2006; 117: 845-850
- Cutaneous perception thresholds of electrical stimulation methods: comparison of tDCS and tRNS.Clin Neurophysiol. 2010; 121: 1908-1914
- Transcranial direct current stimulation and the visual cortex.Brain Res Bull. 2006; 68: 459-463
- tDCS polarity effects in motor and cognitive domains: a meta-analytical review.Exp Brain Res. 2011; 216: 1-10
- Determinants of voltage attenuation in neocortical pyramidal neuron dendrites.J Neurosci. 1998; 18: 3501-3510
- Pyramidal neurons: dendritic structure and synaptic integration.Nat Rev Neurosci. 2008; 9: 206-221
- Neurological anatomy in relation to clinical medicine.3rd ed. Oxford University Press, New York1981
- The neuron.in: Cell and molecular biology. 3rd ed. Oxford University Press, New York2002
- Extracellular stimulation of mammalian neurons through repetitive activation of Na+ channels by weak capacitive currents on a silicon chip.J Neurophysiol. 2008; 100: 346-357
- Principle of neural sciences.4th ed. McGraw-Hill, 2000
- Time course of the induction of homeostatic plasticity generated by repeated transcranial direct current stimulation of the human motor cortex.J Neurophysiol. 2011; 105: 1141-1149
- Shaping the optimal repetition interval for cathodal transcranial direct current stimulation (tDCS).J Neurophysiol. 2010; 103: 1735-1740
- Induction of late LTP-like plasticity in the human motor cortex by repeated non-invasive brain stimulation.Brain Stimul. 2013; 6: 424-432
- Safety and cognitive effect of frontal DC brain polarization in healthy individuals.Neurology. 2005; 64: 872-875
- Preconditioning of low-frequency repetitive transcranial magnetic stimulation with transcranial direct current stimulation: evidence for homeostatic plasticity in the human motor cortex.J Neurosci. 2004; 24: 3379-3385
- Depression of human corticospinal excitability induced by magnetic theta-burst stimulation: evidence of rapid polarity-reversing metaplasticity.Cereb Cortex. 2008; 18: 2046-2053
- Simply longer is not better: reversal of theta burst after-effect with prolonged stimulation.Exp Brain Res. 2010; 204: 181-187
Article info
Publication history
Published online: January 21, 2013
Accepted:
December 21,
2012
Received in revised form:
December 21,
2012
Received:
September 20,
2012
Footnotes
Cornelia Pirulli and Anna Fertonani contributed equally to this work.
The authors declare no conflict of interest.
Identification
Copyright
© 2013 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
