Poster Session F, Tuesday, March 26, 8:00 – 10:00 am, Pacific Concourse
Diffusion markers of dendritic density and arborization in gray matter predict differences in intelligence
Erhan Genc1, Christoph Fraenz1, Onur Güntürkün1, Rex Jung2; 1Biopsychology, Department of Psychology, Ruhr University Bochum, Germany, 2Department of Psychology, University of New Mexico, Albuquerque, New Mexico, USA
Previous research has demonstrated that individuals with higher intelligence are more likely to have larger gray matter volume in brain areas predominantly located in parieto-frontal regions. These findings were usually interpreted to mean that individuals with more cortical brain volume possess more neurons and thus exhibit more computational capacity during reasoning. In addition, neuroimaging studies have shown that intelligent individuals, despite their larger brains, tend to exhibit lower rates of brain activity during reasoning. However, the microstructural architecture underlying both observations remains unclear. In this study we assessed microstructural brain anatomy within a large sample of 259 healthy individuals using advanced multi-shell diffusion tensor imaging also known as neurite orientation dispersion and density imaging (NODDI). Further, we conducted a culture-fair matrix-reasoning test in order to measure fluid intelligence. We found that higher intelligence is related to lower values of dendritic density and arborization. We were able to cross-validate our results with data from 506 individuals provided by the Human Connectome Project. Most likely, these findings demonstrate that the neuronal circuitry associated with higher intelligence is organized in a sparse and efficient manner, fostering more directed information processing and less cortical activity during reasoning. In conclusion, this study substantially extends our knowledge about the biological basis of human intelligence differences, by providing insights to efficient information processing during reasoning at the level of axons or dendrites.
Topic Area: THINKING: Reasoning