Smarter Brains Run on Sparsely Connected Neurons

Summary: A new study reveals the brains of higher IQ people tend to have leaner, yet more efficient neural connections. Researchers report, the more intelligent a person, the fewer dendrites they have in their cerebral cortex.

Source: RUB.

The more intelligent a person, the fewer connections there are between the neurons in his cerebral cortex. This is the result of a study conducted by neuroscientists working with Dr Erhan Genç and Christoph Fraenz at Ruhr-Universität Bochum; the study was performed using a specific neuroimaging technique that provides insights into the wiring of the brain on a microstructural level.

Together with colleagues from the University of New Mexico in Albuquerque, Humboldt University of Berlin and the Lovelace Biomedical and Environmental Research Institute in Albuquerque, the team from the biopsychology research unit in Bochum published their report in the journal Nature Communications on May 15, 2018.

Intelligence is determined by the number of dendrites

The researchers analysed the brains of 259 men and women using neurite orientation dispersion and density imaging. This method enabled them to measure the amount of dendrites in the cerebral cortex, i.e. extensions of nerve cells that are used by the cells to communicate with each other. In addition, all participants completed an IQ test. Subsequently, the researchers associated the gathered data with each other and found out: the more intelligent a person, the fewer dendrites there are in their cerebral cortex.

The new findings provide an explanation of conflicting results gathered in intelligence research to date. image is in the public domain.

Using an independent, publicly accessible database, which had been compiled for the Human Connectome Project, the team confirmed these results in a second sample of around 500 individuals.

Previously conflicting results are thus explained

The new findings provide an explanation of conflicting results gathered in intelligence research to date. For one, it had been previously ascertained that intelligent people tend to have larger brains. “The assumption has been that larger brains contain more neurons and, consequently, possess more computational power,” says Erhan Genç. However, other studies had shown that – despite their comparatively high number of neurons – the brains of intelligent people demonstrated less neuronal activity during an IQ test than the brains of less intelligent individuals.

“Intelligent brains possess lean, yet efficient neuronal connections,” concludes Erhan Genç. “Thus, they boast high mental performance at low neuronal activity.”

About this neuroscience research article

Funding: The research was supported by the German Research Foundation, Mercur.

Source: Erhan Genc – RUB
Publisher: Organized by
Image Source: image is in the public domain.
Original Research: Open access research for “Diffusion markers of dendritic density and arborization in gray matter predict differences in intelligence” by Erhan Genç, Christoph Fraenz, Caroline Schlüter, Patrick Friedrich, Rüdiger Hossiep, Manuel C. Voelkle, Josef M. Ling, Onur Güntürkün & Rex E. Jung in Nature Communications. Published May 15 2018.

Cite This Article

[cbtabs][cbtab title=”MLA”]RUB “Smarter Brains Run on Sparsely Connected Neurons.” NeuroscienceNews. NeuroscienceNews, 17 May 2018.
<>.[/cbtab][cbtab title=”APA”]RUB (2018, May 17). Smarter Brains Run on Sparsely Connected Neurons. NeuroscienceNews. Retrieved May 17, 2018 from[/cbtab][cbtab title=”Chicago”]RUB “Smarter Brains Run on Sparsely Connected Neurons.” (accessed May 17, 2018).[/cbtab][/cbtabs]


Diffusion markers of dendritic density and arborization in gray matter predict differences in intelligence

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. By combining advanced multi-shell diffusion tensor imaging with a culture-fair matrix-reasoning test, we found that higher intelligence in healthy individuals is related to lower values of dendritic density and arborization. These results suggest 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.

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  1. Tony, is this like “They can send a man to the moon but they can’t make a decent f-ing cheeseburger”? If so, I’m totally with you. If not, then you’re kind of being a jerk to researchers who are already doing everything they can, short of quitting their jobs and acquiring the expertise to diagnose and administer.

    Either way, the solution is to quit your job and go into politics so you can influence the laws that can make it possible or mandatory to make good cheeseburgers and/or properly diagnose and administer the proper medication and treatments.

    I’m being wry but I’m also being genuine. I think you’re right, but I think you’re barking at the wrong people. Demand it of yourself instead. If science committees are any indication, you need absolutely no prior medical experience or even basic familiarity with science to accomplish this.

  2. The finding seems counter-intuitive at first blush, but it may imply that intelligent people rely less on memorization and more on process and analogy, e.g., their brains perform more efficiently due to more transferable modeling of their observations and experiences.

  3. They can do all this research but yet fail to properly diagnose and administer the proper medication and treatments for the various ways victims of depression and and anxiety disorders. Why do they use runs trial and error of medications on patients with depression without for going proper procedures to diagnose the depression, ie. Some people have poor axons or dendrite receptors, others lack the molecules that carry the neural transmitters across the synaptic cleft. Others lack the production of specific neural transmitters, and others lack or produce certain alpha and beta blockers.
    These tests could be done so as to provide the proper medication that goes with the specific deficiency in the brain. And yet they none of this is being questioned and they keep throwing out these antidepressants without regard to the proper disorder. Answering the question to why certain meds work on some and yet don’t work 9n others.
    Depression is a serious condition and causing suffering and suicide rising I to the epidemic proportions. Yet nobody in the psychology departments or heads of neuroscience or proposing mandatory tests like I mentioned to align the proper disorder to the proper treatment and specific medications. Yea you all really care alright!!!!!

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