Some Shocking News About tDCS

The sun is out, the birds are chirping, and the annual sod placement is well underway. These events may signify the arrival of spring to many, but for college students it means something else: finals season. Many on campus may be considering different study strategies as their tests loom ahead, likely in the form of caffeine schedules and study guides. However, some may attempt to use a more neurological based method of academic enhancement.

A  method of brain stimulation known as trans-cranial direct current stimulation (tDCS) has been used as a cognitive aid for over a decade. This technique involves targeting certain cortices in the brain with electric currents in order to stimulate neuron activity and enhance brain functioning. The line of research on tDCS typically attempts to investigate its capacity to improve brain function in subjects with cognitive deficits. The findings that suggested tDCS had a cognitive enhancement function caused a wave of home-use of the treatment in the early 2000s. The video below is a tutorial for how to make your own tDCS device, to stimulate brain activity.

However, a new finding has created concern regarding the long term effects of this treatment. Sellers et al (2015) found that long term tDCS treatment actually has detrimental effects on subjects’ IQ. The study implied that previous studies on tDCS were not sufficiently rigorous. Specifically, they failed to used proper double blind and control groups, which likely made their results unreliable. Sellers et al. (2015) tested 40 healthy adults, giving half tDCS treatment, and the other half a sham electric current that did not stimulate the brain. Stellers et al. (2015) found a decrease in IQ scores following the tDCS treatment, particularly in the perceptual reasoning portion. The finding that tDCS can decrease IQ is intriguing and concerning because it challenges years of assumptions about electric current stimulation and its potential benefits for cognitive function.

Despite the finding about tDCS, other forms of electric current stimulation don’t seem to have the same negative effects. A different electronic current strategy, known as tACS, mimics the naturally fluctuating electric currents in the brain. Sellers et al. (2015) found that this therapy did not have the detrimental effects to IQ. This created promising evidence that some electro-stimulation can still be beneficial in improving cognitive deficits, but that stimulation must be targeted and it must better reflect natural stimulation of the brain’s neurons.

The findings of this research provide evidence for why we should be skeptical about brain enhancing therapies and treatments. When our understanding the brain is so limited, it is important to be cautious of altering its function unless absolutely necessary. However upsetting it might be to hear, this means no magical short cuts for memorizing all of those brain regions for your Biological Basis of Behavior class, just good old fashioned coffee and flashcards.



  1. Kristin K. Sellers, Juliann M. Mellin, Caroline M. Lustenberger, Michael R. Boyle, Won Hee Lee, Angel V. Peterchev, Flavio Frohlich. Transcranial direct current stimulation of frontal cortex decreases performance on the WAIS-IV intelligence test. Behavioural Brain Research, 2015; DOI: 10.1016/j.bbr.2015.04.031

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