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Fundamental research

20 - 02 - 2018

The root cause of individual behaviour

Researchers have unveiled the role of serotonin in the onset of individual behaviours by studying genetically identical worms maintained in identical environments.


Researchers are trying to understand the internal mechanisms that give rhythm to spontaneous behaviours such as food intake.


For this purpose, they developed a system to monitor fifty Caenorhabditis elegans throughout their fifty-hour development.




They found that the frequencies of activity, especially foraging, were about the same in all individuals raised separately.


They were able to cause genetic mutations in these worms and observe the effect of suppressing certain modulators of behaviour. For example, suppressing dopamine decreases the speed of movement at the end of development.


In addition, this study revealed individual behaviours: some animals did not exhibit the same behaviours as the majority of other individuals.


The cause of this individualism cannot be related to genetics or the environment in this study, we can question small differences in the development of neurons for which a part of chance is inevitable.


However, by wanting to check for the possible effect of neuromodulators, the researchers tested the absence of serotonin and they were surprised to discover the disappearance of almost all individual behaviours!


It therefore seems that evolution has created a system to guarantee the existence of individual behaviours, an essential asset for the survival of species.