Brain Decline Comes Later Than Previously Thought

Summary: Brain decline begins during our 30s and 40s, and not at age 25 as previously believed, researchers say.

Source: University Medical Center Utrecht

Recent research from University Medical Center Utrecht (UMC Utrecht) shows that our brain declines later than previously thought. Instead of after our 25th year of life, it happens when we are between the ages of 30 and 40.

The researchers published their results in Nature Neuroscience.   

Clinical technologist Dorien van Blooijs and neurologist Frans Leijten, together with colleagues from UMC Utrecht and the Mayo Clinic, conducted research into the processing speed of our brain and how it changes as we age. 

Faster connections

The researchers discovered, among other things, that the connections in our brains become increasingly faster: from two meters per second in children aged four to four meters per second in people aged between thirty and forty. A doubling, in other words. Only after that age does it slow down.

“Our brain continues to develop a lot longer than we thought,” Van Blooijs said.  

The researchers also see differences between brain regions. The frontal lobe, the front part of our brain responsible for thinking and performing tasks, develops longer than an area responsible for movement.

Van Blooijs explains, “We already knew this thanks to previous research, but now we have concrete data.” The development of speed is not a straight line, but rather a curve. 

Brain map

The researchers obtained the data by making precise measurements using an electrode grid that some epilepsy patients get placed on their brain (under the skull) in preparation for epilepsy surgery. The grid consists of 60-100 electrodes that can measure brain activity.

“By stimulating the electrodes using short currents, we can see which brain areas respond abnormally. Thus, we can create a map of which areas should and should not be removed during epilepsy surgery,” Leijten said. 

The fact that the data could also teach the researchers something about how our brain works was a new insight. “We have been collecting this data for about 20 years,” Leijten said.

“It wasn’t until a few years ago that we realized we could use the unaffected areas as a model for the healthy human brain.”  

Van Blooijs adds: “If you stimulate an electrode in one area, a reaction occurs in another. That lets you know the two areas are connected. You can then measure how long it takes for the reaction to occur. If you know the distance between the two different brain regions, you can calculate how fast the signal is transmitted.”  

Better computer models

The results of this study provide important information about our central nervous system. Scientists have long been trying to map the connections in our brain. With this information, experts can make more realistic computer models of our brain. 

This shows a brain
The results of this study provide important information about our central nervous system. Image is in the public domain

For these models to work, in addition to information about the connections, precise values concerning the speed of those connections are needed. “We now have these numbers for the very first time,” Leijten explains.

“With our data, researchers can make new and better computer models that increase our understanding of the brain. We expect our work to not only advance epilepsy research, but also research into other brain disorders.” 

Open to progress  

With this publication in Nature Neuroscience, all data has become publicly accessible. This is called Open Science and it means that researchers from all over the world can use the data.

Leijten: “By participating in research, patients contribute to progress. The knowledge we gain can be used to better treat future patients.” Van Blooijs will receive her doctorate at the end of this year.

She says, “A lot is possible with this data, more than we can do. I’m curious to see what kind of research all the creative people around the world will come up with.” 

About this neuroscience research news

Author: Jerwin de Graaf
Source: University Medical Center Utrecht
Contact: Jerwin de Graaf – University Medical Center Utrecht
Image: The image is in the public domain

Original Research: Open access.
Developmental trajectory of transmission speed in the human brain” by Dorien van Blooijs et al. Nature Neuroscience


Developmental trajectory of transmission speed in the human brain

The structure of the human connectome develops from childhood throughout adolescence to middle age, but how these structural changes affect the speed of neuronal signaling is not well described.

In 74 subjects, we measured the latency of cortico-cortical evoked responses across association and U-fibers and calculated their corresponding transmission speeds.

Decreases in conduction delays until at least 30 years show that the speed of neuronal communication develops well into adulthood.

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