Tübingen researchers trace the formation of memories in the cerebral neocortex
A team of researchers from the University of Tübingen and the Max Planck Institute for Biological Cybernetics has found that the cerebral cortex plays a much bigger role in storing information than previously believed. The scientists, headed by Svenja Brodt, Professor Steffen Gais and Dr. Monika Schönauer, used high-resolution magnetic resonance imaging to show that the cerebral cortex is involved already early in the learning process.
Neuroscience now has to update a widely accepted model, which says this part of the brain is a slow learner. The new study is published in Science.
For centuries, researchers have been trying to track down the secrets of human memory. For a long time, processes that form new memories were barely understood. Traditional models assume that the brain has two systems for memory – one in the hippocampus, which takes in large amounts of information quickly, and the other in the cerebral cortex, where lasting memories can be stored through repeated learning.
The physical signs of memory formation
In this new study, the researchers gave their test subjects a learning task in which they had to remember several pairs of objects and their spatial arrangement on a computer screen – as in a children’s game of “pairs.” While they conducted this task, their brain activity was recorded by an MRI scanner. The researchers also carried out a special measurement showing the brain tissue microstructure.
They used a process called diffusion-weighted imaging, which measures the motion of water molecules in the brain. Because water is slowed down by cell membranes, tracking its motion gives the scientists detailed information about the tissue structure. Measurements were taken at three times: immediately prior to the learning task, 90 minutes later and twelve hours later.
“A comparison of the diffusion images before and after learning with a control condition allowed us to draw conclusions about smallest changes in tissue structure caused by the learning process,” explains lead author Svenja Brodt. Thus, traces of the learning process can be observed in the inactive state following completion of the learning task.
“We are moving away from mere snapshots of brain activity taken while the brain is absorbing or recalling information towards an examination of the physical traces left by the storing of information in our brains,” Brodt says.
With the help of diffusion-weighted imaging, researchers were able to measure structural changes in the cerebral cortex already 90 minutes after learning – in precisely those regions that showed strong memory-related activity during the learning task.
The strongest changes were found in the back of the parietal lobe, the posterior parietal cortex. The bigger these changes were, the better the test subjects could remember the object pairs in the long term.
Stable changes in the cerebral cortex
“These structural changes are not a short-term by-product of increased cell activity during learning, because they remain stable for at least twelve hours,” says study leader Monika Schönauer. She says studies on animals show that these changes are linked to a strengthening of connections between nerve cells, the so-called synapses.
“Our results confirm that the cerebral cortex plays a role early on in learning processes, and show that it is immediately involved in the physical storage of information,” Schönauer states. “The earlier assumption that the cerebral cortex learns only slowly can no longer be maintained.”
Head of the working group Steffen Gais adds: “Our findings in recent years have great significance for the further development of current theories about memory formation.”
These new findings offer an explanation as to how patients with a damaged hippocampus are in some cases able to learn and remember new information, Gais says. The further investigation of the conditions under which information is stored directly in the cerebral cortex could help in the long term to develop new learning strategies for certain types of memory loss.
University of Tübingen
Institute of Medical Psychology and Behavioral Neurobiology
Phone +49 7071 29-73264
S. Brodt, S. Gais, J. Beck, M. Erb, K. Scheffler, M. Schönauer: Fast track to the neocortex: A memory engram in posterior parietal cortex. Science, 30 November 2018.
Dr. Karl Guido Rijkhoek | idw - Informationsdienst Wissenschaft
Exciting Plant Vacuoles
14.06.2019 | Julius-Maximilians-Universität Würzburg
A microscopic topographic map of cellular function
13.06.2019 | University of Missouri-Columbia
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.
The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....
Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.
Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...
Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.
Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
14.06.2019 | Information Technology
14.06.2019 | Materials Sciences
14.06.2019 | Medical Engineering