The mouse thalamus starts to separate sensory and movement functions before birth

Before the brain can organise the world like an office with different departments, some of its cells are already beginning to choose which team to join. A study by the UMH-CSIC Institute of Neuroscience has charted how two major lineages of thalamic neurons become specialised in mice: one linked to sensory functions and the other associated with motor and associative functions.

The thalamus is a brain region made up of different nuclei. It transmits and integrates sensory information and also plays a part in motor and associative functions. Put simply, it is less like a mere corridor and more like a communications hub with several lines. The research examines how its cells acquire their identities during embryonic development.

The study, published in Nature Neuroscience on 20 October 2026, analysed 25,477 individual cell profiles. To create this map, the team combined information about active genes and accessible regions of DNA at three stages of mouse embryonic development: E11.5, E14.5 and E16.5. Rather than looking at a single snapshot, the scientists followed different points in a process still under way.

They also used genetic labelling to track the fate of progenitor cells and experimentally tested relationships between cell lineages. The research involved the UMH-CSIC Institute of Neuroscience and the University of Geneva. The findings help explain how cells in the midst of development take different paths, like employees assigned to different roles in an organisation that is still being set up.

Within the sensory lineage, the authors identified pathways leading to visual and somatosensory neurons. The latter are linked to information from the body. Both pathways pass through a molecular state resembling that of “higher-order” thalamic neurons. The phrase may sound like an office ranking, but it describes a molecular stage observed as these cells develop.

The team also experimentally reduced the activity of the Sp9 gene during mouse embryonic development. Under these conditions, certain neurons did not acquire their visual identity correctly. This offers a clue to the gene’s importance in the process studied, not a conclusion about what happens in every pregnancy or a complete explanation of how vision develops.

The researchers also found that sensory development programmes reach some stages earlier than those linked to motor and cognitive functions. This finding relates to the circuits studied in mice. It does not show that a human baby actively distinguishes, before birth, between what it feels and the commands that move its body: it describes how thalamic cells become specialised during embryonic development.

The research provides a framework for studying how thalamic circuits are built and possible neurodevelopmental disorders, but it does not establish clinical applications or findings in human babies. If you have any questions about health or development, you should consult a doctor or pharmacist.

Did you know? The visual and somatosensory neurons identified share, along their developmental pathways, a molecular state resembling that of “higher-order” thalamic neurons.

Text by Neuro-IA Cortés, La Gaceta de Guardamar’s virtual writer on the human body, an artificial intelligence: prepared using public sources. Sources consulted: , in.. General information: this does not replace advice from your doctor or pharmacist.