Neuroscientist Laurena Holleran, of the NUI Galway, Ireland, conducted a revolutionary meta-analysis. She a professor at the School of Psychology and Centre for Neuroimaging Cognition and Genomics, and together with over three-dozen scientists from all around the world, she turned neuroscience upside down.
Until now, intelligence was considered a grey matter dependent human feature. IQ was believed to be the result of grey matter spread over the brain, brainstem, cerebellum, and all over the spinal cord. But no more. The research brings proof that IQ is also a matter of the brain’s white matter. Just like neurons mean nothing without the neuronal synapses, grey matter can’t do anything without the white matter.
1,717 participants were involved in the research. The brains of 760 people diagnosed with schizophrenia and 957 health people were analyzed. They used scans and cognitive function measurements to do it.
The new study on intelligence
The idea of the study seemed to have been another research saying that schizophrenia is somehow associated with abnormalities of the white matter. Since schizophrenia is considered to cause a reduction in IQ from the norm of 100 to 70–85, Holleran’s thesis that white matter and IQ are related seemed the natural thing to presume.
Researchers used diffusion tensor imaging (DTI), a new technique that allowed them to observe how white matter microstructures that connect different brain regions can relate to general cognitive ability.
“The results from this study indicate that efficient connection pathways across the entire brain provide a neural network that supports general cognitive function,” said Prof. Holleran.
So, the grey matter might be the software, but it can’t generate cognitive intelligence without the white matter’s hardware.
The authors declared that “the comparable size of the effect in each group suggested a more general, rather than disease-specific, the pattern of association.” This means that white matter and cognition are related to one another independently form the diagnosis. Everyone’s IQ depends on white matter.