Researchers report that a set of brain cells linked to spatial disorientation in Alzheimer’s disease has been preserved across millions of years of evolution. The cells are in the retrosplenial cortex, a brain region that helps animals and people know where they are and how to travel between familiar places. Charles Darwin described the ability of many species to locate themselves without external cues and called it "dead reckoning." Omar Ahmed said the retrosplenial cortex functions as a subconscious GPS and that the region is among the first affected in Alzheimer’s disease.
Ahmed’s team had previously identified a unique neuron type in the mouse retrosplenial cortex. In the new study, first author Isla Brooks and colleagues used advanced AI-based tools to compare genetic signatures of neurons from mice and rats. They found a second specialized neuron type that appears only in the retrosplenial cortex. Both types were preserved across species, and one showed a small amplification in the rat compared with the mouse.
The authors say these neurons likely help animals find their way home. Ahmed’s lab is now investigating whether the same specialized neurons exist in the human retrosplenial cortex and what happens to them in Alzheimer’s disease. The research appears in the Journal of Neuroscience and was supported by the National Institutes of Health and the Alzheimer’s Association.
Difficult words
- retrosplenial cortex — brain region that helps animals know location
- spatial disorientation — difficulty knowing where you are or how to travel
- neuron — nerve cell that sends signals in the brainneurons
- genetic signature — unique DNA or gene pattern for a cellgenetic signatures
- subconscious — mental process happening without active thought
- preserve — keep something the same over timepreserved
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Discussion questions
- Why is it important to study whether the same specialized neurons exist in humans?
- How could damage to a subconscious GPS affect a person’s daily life?
- Have you ever been lost in a familiar place? How did you find your way back?
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