Geneva: Some researchers from Geneva have studied the neurobiological mechanisms to find that the motivation to indulge in social interactions is the activation of dopaminergic neurons.
The study has been published in the 'Nature Neuroscience Journal'. These results will make it possible to study physiologically the possible dysfunctions of these neurons in diseases affecting social interactions, such as autism, schizophrenia, or depression.
"In order to observe which neurons are activated during social interaction, we taught mice to perform a simple task that allows them to enter in contact with their fellow mouse," explained Camilla Bellone, professor in the Department of Basic Neuroscience at the UNIGE Faculty of Medicine and director of the NCCR Synapsy.
Two mice were placed in two different compartments and separated by a door. When the first mouse pressed a lever, the door opened temporarily, allowing social contact to be established with the second mouse through a grid.
"As the experiment progressed, the mouse understood that it had to press the lever to join its fellow mouse. With this task, we can measure the effort the mice are willing to put to engage in interaction with conspecifics," continued Clement Solie, a researcher in Camilla Bellone's team.
Using electrodes, the scientists measured the activation of neurons.
"We found that the interaction between two mice, similarly to other natural rewards, led to the activation of dopaminergic neurons, which are located within the reward system," said Camille Bellone.
These neurons release dopamine -- the so-called pleasure molecule -- which is crucial for several motivated behaviours.
"What is even more interesting is that while during the first sessions, the dopaminergic neurons are activated when the mice interact with the conspecific, as soon as the mouse learn the association between the lever press and the interaction, the activity of dopaminergic neurons precedes the reward," continued Benoit Girard, a researcher in the Department of Basic Neuroscience.
"Similarly, if the mouse presses the lever but the door does not open in the end, there is a sudden drop in the activity of the dopaminergic neurons, indicating great disappointment in the mouse," explained Camilla Bellone.
"This predicting signal is the neural substrate for learning and is crucial for social motivation," Bellone added.