How our brain is wired: A team from Geneva and Dresden shows the formation and specialization of neuronal networks

Our brain is a highly complex organ whose functioning depends on countless connections between nerve cells. In collaboration with Prof. Denis Jabaudon from the Université de Genève, Dr. Philipp Abe from the Institute of Anatomy at the Faculty of Medicine at TU Dresden was able to show how these connections form and specialize during development. These important findings were published in the renowned scientific journal “Nature”.

© Universität Genf

The outer layer of our brain, the cortex or cerebral cortex, is divided into different areas. Each area has specific tasks, such as controlling movements or processing sensory information such as sight, hearing and touch. Within these areas there are different types of nerve cells, each of which fulfills specific functions. Among these, the so-called ET neurons have particularly long “connecting cables”. These long connections enable them to communicate with other, distant areas of the brain.

Development of the connection pathways

In early development, ET neurons initially form numerous connections to different target areas in the brain. In the course of development, however, many of these connections are broken down again. This process, known as “pruning”, varies from area to area and is controlled by specific genetic programs. For example, longer connections to the spinal cord develop in the motor cortex, while shorter connections to the thalamus are formed in the visual cortex, where it is decided which impressions from the environment - seeing, hearing, bodily sensations - are passed on to the cerebrum for consciousness.

Genetic control of networking

Researchers at the Dresden University Medical Center have now been able to identify certain genes that control the development of ET neurons and their connecting pathways. These genes act like blueprints that provide specific instructions for the formation and breakdown of neuronal connections. By specifically inactivating these genes, it has been shown that the connection patterns of ET neurons can be altered, providing new insights into the mechanisms of neuronal plasticity, and these new findings could help to develop new treatments for diseases in which the connections in the brain are damaged or defective, such as spinal cord injuries or certain hereditary diseases.

The importance of cell types and areas

The study shows that both the type of nerve cell (ET neuron) and the area in which it is located play a decisive role in the development of neuronal connections. The combination of these two factors creates a highly specialized wiring of the brain that enables us to perceive, learn and act in our environment.

Outlook

These new findings open up new perspectives for research into neurological diseases in which the development of neuronal connections is disrupted. In the long term, these insights could also contribute to the development of innovative therapeutic approaches for neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) or hereditary spastic paraplegia (HSP).

Abe, P., Lavalley, A., Morassut, I. et al. Molecular programs guiding arealization of descending cortical pathways. Nature (2024). https://doi.org/10.1038/s41586-024-07895-y

Contact:
Dr. Philipp Abe
Institute for Clinical Genetics
+49 (351) 458-17955
 |
https://www.uniklinikum-dresden.de/kge

Prof. Denis Jabaudon
Department of Basic Neurosciences
Campus Biotech, Université de Genève, Schweiz
+41 22 37 95 387
denis.jabaudon@unige.ch
https://neurocenter-unige.ch/research-groups/denis-jabaudon