BIOCEV zoologists have helped to elucidate the neural coding of odours in the mouse brain
Research — 15.07.2021

Lipocalins in Modulation of Mammalian Reproduction

BIOCEV zoologists have helped to elucidate the neural coding of odours in the mouse brain

An international team represented by zoologists Pavel Stopka and Romana Stopková (both from the Faculty of Science, Charles University at the BIOCEV centre) explained how the smells of various mouse lines, including their subspecies and the opposite sex, are perceived. The results of this Israeli-German-Czech collaboration were published in the prestigious scientific journal BMC Biology.

Using a series of experiments, the researchers were able to prove that mice maintain a stable representation for recognizing a subspecies with which they can no longer mate, as well as for detecting the opposite sex, for which the individual increases their biological fitness. Other specific neurons of the studied mice are used to detect a predator or another male that is its competitor. The fact that mice have stable representations of the subspecies they separated from 500,000 years ago dispels the well-established myth that the most important barrier against sterile crossing is urinary signals.

“New research suggests that changes have occurred both on the side of signals and on the side of the detection and evaluation of these signals in the accessory olfactory bulb in the brain,” explains Romana Stopková.

By interacting with their environment, animals generate sensory representations in the brain through the chemosensory neurons of the main and accessory olfactory organs. These representations are evaluated by different parts of the olfactory bulb in the brain and are further associated with a specific ethological response. If in an experiment several individuals "agree" on a specific representation, i.e. respond to the same stimulus with the same neurons of the accessory olfactory bulb, then this information is also passed on to other areas of the brain.

The international team used hundreds of proteomically and metabolomically analysed urine samples from laboratory and feral mice and also the predator urine to serve as one of the controls for the research. These were then presented by Israeli colleagues to the mice in their accessory olfactory organ (the so-called Jacobson's or vomeronasal organ). They then recorded different activities in hundreds to thousands of neurons with a special probe placed in the accessory olfactory bulb. “This research is important because humans have evolutionarily lost their accessory olfactory organ, and in order to know what we have lost, it is necessary to carry out this research on mice,” adds Pavel Stopka.

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Photo: Romana Stopková