Brain Training + Zapping
The Goal: Apply direct current brain stimulation during brain training video games to enhance performance.
For my dissertation, I helped design and run one of the biggest brain training studies ever conducted. We put over 500 people through a 4-month program of exercise, brain training video games, and brain stimulation.
Enhancing fluid intelligence is the holy grail of brain training, but it's a complex cognitive construct that's hard to improve directly. It overlaps with working memory and executive function, though, which are are more malleable. We measured these constructs at the start and end of the study to track how much people improved.
Experimental Design
We designed a brain training videogame called Mind Frontiers (don't ask about the wild west theme) with 6 mini-games:
We designed a brain training videogame called Mind Frontiers. (Don't ask about the wild west theme.) The game comprised 6 mini-games, based on widely used cognitive tests.
Sentry Duty, for example, was a gamified version of the dual N-back task, which has been shown to improve working memory. Pen 'Em Up was a task-switching game that stressed executive function. Ante Up was based on the Tower of London task, thought to rely on fluid intelligence.
Brain Stimulation
Transcranial direct current stimulation (tDCS) works by running electric current into your brain via electrodes on your scalp. Don't worry, it uses such a small amount of current (1/500 of an iPhone charger) that it barely even tickles. As the current passes through your brain, it changes how often neurons fire.
There's a saying in neuroscience: "Neurons that fire together wire together". By using tDCS to stimulate relevant parts of the brain, we sought to enhance cognitive performance by strengthening neuronal connections.
Electricity follows the path of least resistance, which lets you target different brain regions by positioning the electrodes in certain ways. We wanted to target the prefrontal cortex and the hippocampus: brain regions critical to working memory, executive function, and fluid intelligence.
By modeling the current flow through the brain, we discovered that running current in above the forehead and out the back of the head would stimulate the prefrontal cortex and the hippocampus along the way.
Experimental Design
Participants played Mind Frontiers for 20 sessions while receiving tDCS. The Active Stimulation group received tDCS for 30 minutes every brain training session. We ramped the current up and down the current over 30 seconds to make it comfortable.
Any good experiment needs a good control group. Our Placebo Stimulation group received 30 seconds of stimulation at the start and end of each brain training session. This meant they felt the tingling of the current ramping up, but their patterns of brain activity were unaffected. When we asked participants after the study, they couldn't reliably tell if they had received real or placebo stimulation.
The Great Wall of Batteries
Ever wonder how many 9v batteries it takes to run 2500+ hours of brain stimulation? It's this many.
Results
So did it work? Kind of.
The Active (red) group performed better than the Placebo (blue) group in most of the games, but these improvements were limited to the brain training games. We didn't find any meaningful differences between the Active and Placebo groups in executive function, working memory, or fluid intelligence at the end of the study.
In other words, brain stimulation made people better at the brain training games, but it didn't improve their overall cognitive abilities.
To learn more, check out the paper we published.
