Sci got an email the other day. Ok, I get lots of emails, but this one asked a cool question, which is always nice. All it asked for was an opinion on an article in Scientific American: “Get Better at Math By Disrupting your Brain“. Sci looked. Was intrigued. Read the actual paper…and found the SciAm coverage of it somewhat misleading (or at least, really confusing).
Basically, the article at SciAm states that
The goal of the study was to assess whether modifying activity in the parietal lobes affected the acquisition of number competence.
If the brain functions by optimizing behavior, it might be possible to worsen numerical competence by disrupting parietal function, but it should not be possible to enhance it that way. However, that is precisely what Cohen Kadosh’s team found. Remarkably, this improvement was still present six months after the training.
The problem isn’t so much in the total coverage itself. The problem is in the word “disruption“. You keep using that word. I do not think it means what you think it means.
(Source)
dis·rupt (ds-rpt)
tr.v. dis·rupt·ed, dis·rupt·ing, dis·rupts
1. To throw into confusion or disorder: Protesters disrupted the candidate’s speech.
2. To interrupt or impede the progress, movement, or procedure of: Our efforts in the garden were disrupted by an early frost.
3. To break or burst; rupture.
So you’d THINK, based on the SciAm article and the definition of the word “disruption”, that this paper used magnets to disrupt me, by which they mean to impede or interrupt, implying a negative effect on brain activity in the parietal lobe, and this paradoxically (as the SciAm article notes) made people better at math.
That would be cool. If that was what the paper actually FOUND. It wasn’t.
And so, I’m going to cover the paper for you all. Let’s clear this up.
Kadosh et al. “Modulating Neuronal Activity Produces Specific and Long-Lasting Changes in Numerical Competence” Current Biology, 2010.
So basically, there are a lot of people out there who are bad at math. I know that sounds really silly, but apparently about 20{9f43b4361d9a125bc126dd2a2d1949be02545ec69880430bc4fed2272fd72da3} of people have ‘numerical difficulties’, wherein math is very difficult for them, making it hard for them to succeed in certain jobs or at certain tasks. Not only that, many people who suffer from strokes will suffer damage to their numerical processing abilities.
(someone who does not suffer any difficulties in numerical processing. Really, this isn’t an example, but I love him so much!)
People who have difficulties with numbers often have functional or structural abnormalities in the right parietal lobe. This is an area of your brain that is usually thought of as being involved in sensory processing, but it’s also involved in things like your “number sense”.
(Source)
EDIT: The following has been clarified by commenter Superkuh. So this paper involves math, the parietal lobe, and a technique called transcranial direct current stimulation (TDCS). Basically, you just attach conductive wires to the skin and use a current limited circuit to run electricity one direction through a the volume of tissues between the two electrodes. The stimulation, depending on the current polarity, electrode placement on the scalp, and pulse rate, can depolarize different kinds of neurons (depolarization is part of an action potential, and what makes a neuron “fire”. For more on that, see my Science 101 post on it). TDCS can also cause long term effects within the neurons, leading to potential long term changes in function.
So the idea here was to see how TDCS affected numerical processing in the brain, using humans. TDCS is not particularly risky (there’s a minor risk of seizures). Sci has actually been in a study on this before (they made my fingers JUMP using magnets on my HEAD. There is nothing quite so creepy as watching your finger move entirely of its own volition). They had the participants learn the associations between random symbols, without learning their number value. So, by the rules of the test $ is greater than &, but you don’t necessarily know whether $ is 45 or 3, and whether & is 27 or 1. You just know that one is bigger than the other. Each time the participants were trained on the task, they got a weak current applied to their heads. 1/3 of the group got a a cathodal application to the right parietal lobe and an anodal application to the left parietal lobe (RC-LA), 1/3 got anode application to the right and cathode on the left (RA-LC), and one group just got a quick jolt that didn’t have any known effects.
After six days of training, they tested their performance in various mathematical tasks.
What they found was that the RA-LC group had increased mathematical task performance, while the opposite group (RC-LA) underperformed.
And here’s where the Sci Am article, in my opinion, got misleading. Because ANODE stimulation ENHANCES neuronal activity in TDCS. It doesn’t “disrupt” it or decrease the activity. It ENHANCES it. Cathode stimulation does the opposite.
This means that if you got Anode stimulation in the RIGHT Parietal cortex, you actually got ENHANCEMENT of the neuronal activity there. This is not a “disruption”. It means they got what they were expecting to get. Enhance neuronal activity in the right parietal lobe during training, enhance mathematical performance. Decrease neuronal activity there, and decrease mathematical performance.
The best part, though, is actually that the effects persisted. The RA-LC group (the enhanced group) STILL had improvements over six months later (apparently the decrease in performance for the other condition didn’t persist). This has some great implications for helping people with severe numerical issues, as well as for helping people who have damage to this area due to stroke (though the stroke condition might make it less effective due to tissue damage in the area, that study will have to be done).
So this is an interesting study. Not sure how it works, as no one is sure how TDCS works, but the effects are there and could be helpful.
But it’s not a “paradoxical behavioral improvement”. This isn’t “disruption” of your neuronal activity proving that your brain works best when it’s NOT working the most efficiently. On the contrary, this study shows that enhancement of neuronal activity in a region led to an increase in a numerical processing outcome. So I’m not really sure how this study is like “swimming and guarding the clothes at the same time” (which seems a lot more like a study in attentional shifting). To my mind, this study has a lot more to do with identifying neuronal networks and areas that change specific behaviors, and affect learning and memory. Not about whether your math gets better with disruption. I’m not sure what story the article at Sci Am was trying to tell, but I feel like it may have confused the issue.
But then again, maybe it just had to do with the use of the word “disruption”. Am I misinterpreting the article? Am I mis-defining the word? Anyone?
Cohen Kadosh R, Soskic S, Iuculano T, Kanai R, & Walsh V (2010). Modulating neuronal activity produces specific and long-lasting changes in numerical competence. Current biology : CB, 20 (22), 2016-20 PMID: 21055945
