Mathematician and philosopher Alfred North Whitehead(1867-1941) understood the role of the intra-parietal sulcus in higher math even though the existence of this structure didn’t emerge until the end of his life, and the function of this bilateral (left brain/right brain) structure didn’t emerge until functional MRI studies showed it, half a century after his death. Whitehead posited that “By relieving the brain of all unnecessary work, a good notation sets it free to concentrate on more advanced problems, and in effect increases the mental power of the race (Introduction to Mathematics (1911, Alfred A. Knopf) Chapter 5).” Now, with the benefit of this powerful imaging connection, we can actually track thoughts jumping around the human brain.
Recall that the intraparietal sulcus mediated the pathway for facts in working memory to be cleared out of the prefrontal cortex once the concept is grasped. This was a key finding for the study of learning in general, and as we will see, of math learning in particular. The purpose of this region of white matter and synapses is to shunt facts in and out of the higher regions of the brain, reducing the cognitive load on the higher brain and allowing it, as Whitehead said, “to concentrate on more advanced problems,” allowing the higher brain to do what it does best: think.
What happens when the brain as a whole isn’t getting arithmetic and higher math, a condition commonly referred to as “dyscalculia”? While there are many reasons that the brain might not “get” arithmetic, from something in the intraparietal sulcus that doesn’t develop along the lines of a neurotypical child to severe mental retardation, most researchers use the term to mean that something is interrupting the normal process of cycling math facts in and out of the left and right intraparietal sulcus, or through this structure into the anterior gyrus. Although there are differences in the two sides of the intraparietal sulcus (the left side being stimulated by visio-spacial input and the right by numerosity), this structure serves as a superhighway, a county road, or an uneven bike path for facts to travel in service of the higher, problem-solving brain’s struggle to master more and more advanced math.
I can hear you arguing, “But I thought you were going to talk about my child! What is this intra-parietal technobabble?” Here’s the point. Butterworth et al. (2011) states,
Reduced grey matter in dyscalculic learners has been observed in areas involved in basic numerical processing, including the left IPS, the right IPS, and the IPS bilaterally; these learners have not developed the brain areas as much as typical learners.
Is it probable that this structure is a superhighway for the gifted math learner, a county road for most of us, and a rubble-strewn bike path for those unfortunates who would now be diagnosed with dyscalculia? This is an area for intensive research taking place right now. What are the implications for the child learner with dyscalculia? Patience, dear reader, we will look at that vital topic in some depth next week.
Butterworth (op.cit.) talks about the need to train the growing brain to do roadway improvements on the IPS to make it easier for facts, once synthesized, to make it into the angular gyrus (another grey matter component implicated by fMRI studies in fact recall), and for those facts to be accessed as needed for problem-solving. Mathnook to the rescue! Our mission is to make math facts automatic and to have the right fact appear in an instant when required for more advanced problem solving.