Dyscalculia And The Brain

We are very pleased to feature a guest post from PD Dr Karin Kucian, associate professor at the Centre for MR Research of the University Children’s Hospital of Zurich. In her article for the Dyscalculia Blog, Dr Kucian explores changes in brain function and brain anatomy and how these relate to developmental dyscalculia.

Evidence is growing that Developmental Dyscalculia (DD) is associated with various altera­tions in brain function and brain structure. Recent work in the field of DD has used brain-imaging techniques to study the brains of people performing a number of tasks. These techniques have allowed researchers to generate high-resolution images of participants’ brains, making it possible to observe brain activation patterns during number processing.

The last few years have given us a clearer picture of what happens in our brains during number processing and calculation. Brain imaging reveals that these operations require an entire neuronal network to carry out. Within this network, an area of the brain called the intraparietal sulcus (IPS) is the centre for numerical processing. You can see the area marked on the illustration.

During research studies, the IPS activated whenever subjects had to deal with numerical magnitude. This included not just math tasks but even situations such as simply looking at changing amounts of dots.

Numerical processing also involves memory, as well as attentional, perceptual, motor, and spatial functions.

Add to this that the prefrontal cortex in general is associated with cognitive processes involved in calculation tasks and we start to get an idea of just how complex is number processing.

Altered brain function in dyscalculia and hope for remediation

Research findings conclude that brain activation pattern during number tasks is less precise in children with DD (developmental dyscalculia). These children may also exhibit deficits in core brain regions used for number processing. To make up for this, dyscalculic children may rely more heavily on supporting brain areas associated with memory, attention, or finger counting. It’s not that dyscalculics use other brain regions to calculate. Rather they need to recruit other regions to make up for reduced activation in areas generally associated with numerical processing.

There is an urgent need to transform this basic knowledge into evidence-based, practical applications for special needs education and remediation. First steps in this direction have already been taken and provide promising results for affected children. Our brain is a highly plastic organ and adapts constantly—not only to typi­cal development but also to special stimulation such as remediation.

What were some of the results when children with dyscalculia completed a specific intervention? Brain imaging depicted a decrease in activation for those supporting areas we talked about. Furthermore, increased activity was observed in areas such as the IPS (see the illustration above) that are pivotal for number processing.

Brain anatomical changes in developmental dyscalculia

There is a growing body of knowledge showing DD is not only associated with alterations in brain activation, but also with changes in brain anatomy. Simply put, our brain can be divided into grey and white matter. Grey matter includes the outer layer of our brain with all the neuronal cell bodies and white matter is the inner part with the axons of the neurons.

When it comes to grey matter, a reduced volume in areas that are thought to play a key role in numerical abilities characterises DD. Basic number processing and calculation depend on a complicated network that includes different and widespread brain areas. In dyscalculics, anatomical alteration in gray matter has been reported across almost the entire network.

These brain regions are linked and communicate by complicated connections among different cortical and subcortical regions. Fast and accurate connections between the different brain regions are crucial for efficient transfer and adjust­ment of information.

There is still little known about impairments of brain connections and how these relate to DD. But the evidence to date supports the hypothesis that developmental dyscalculia is associated with a disconnection or reduced connection between brain areas important for number processing. Affected brain regions appear to vary, which could be explained by the diverse nature of dyscalculia.

Key takeaways:

• Number processing and calculation are highly demanding cognitive skills
• Number skills require a complicated neuronal network

• Deficits in brain function, brain structure, or brain area interconnections have been reported across almost the entire neuronal network of people with dyscalculia
• Brain activation pattern in children with DD is less precise than in those without dyscalculia
• Brain areas affected in dyscalculics are mainly the parietal areas, but other cortical and subcortical regions can also be affected

• The stronger recruitment of supporting areas associated with working memory, attention, monitoring, updating, or finger representation are supposed to reflect compensatory mechanisms in dyscalculic children
• The use of supporting areas for number tasks could also reflect deficits in these domain-general skills that might contribute to the development of DD

• Intervention and remediation for dyscalculic children can improve brain activation in areas associated with number processing
• There is an urgent need to take research findings and apply these towards practical special education resources for dyscalculia

About the author

Karin Kucian studied Neurobiology and Educational Science at the Swiss Federal Institute of Technology. After her PhD on the development of cerebral representations of numbers in typically achieving children and children with developmental dyscalculia, she focused further on the investigation of neuronal correlates of number processing in children with developmental dyscalculia and interventions to improve numerical understanding. In 2015, she obtained the venia legendi of the medical faculty of medicine of the University of Zurich and is now working as an associate professor at the Centre for MR-Research of the University Children’s Hospital Zurich.