In the human brain, neural networks that are used by information to circulate from one region to another are often associated with particular functions (monitoring the environment, initiating movement, regulating behaviour, etc.). They are also altered in many neurological diseases. Understanding how evolution has shaped the architecture of these networks is important to better understand the origin of the exceptional cognitive capacities of humans. The mouse lemur (Microcebus murinus) is one of the smallest and most genetically distant primates from humans.
A team from MIRCen (CEA-Jacob) has characterized for the first time the neural networks of this small primate. This feat is based on the use of a high-performance MRI (11.7 Tesla) allowing non-invasive observation of a brain 800 times smaller than that of humans (1.7 grams versus 1.4 kg). Researchers have identified the networks allowing mouse lemurs to perform motor actions or to process visual information (somatomotor and visual primary networks). Some of the networks identified could be involved in alertness in response to sensory stimuli and in the attribution of positive or negative valences to stimuli (sensori-limbic and limbic-evaluative networks).
The most salient anatomical differences between mouse lemurs and humans are mostly in the high-level neural networks. Human evolution may therefore have specifically modified their organization, often associated with high cognitive functions.
| François Jacob Institute of biology - CEA |
Normandie University
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Université Paris 8
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