The life and soul of the party or an adapting loner – how social is our brain?
When someone panics, others can feel their anxiety. When others laugh, we find it easier to smile. Some of our emotions are not wholly owned by us, we take them from those who surround us. How does our brain process such complex social emotions? A glimpse of the answer has been provided by research of the Nencki Institute, currently carried out on the basis of the prestigious ERC grant, awarded to Dr. Ewelina Knapska.
Humans are social beings. What are their brains like, though? Do they contain structures, which evolved to help us maintain good relations with the rest of our community, or is our ability to sense the emotions of others simply an effect of adaptation, acquisition of new skills by neuronal brain circuits shaped during the much earlier stages of our evolution? In the coming years, research on the mechanisms of processing of social emotions by the brain will be implemented at the Nencki Institute for Experimental Biology of the Polish Academy of Sciences in Warsaw thanks to the prestigious ERC Starting Grant of the value of EUR 1.3 million, awarded to Dr. Ewelina Knapska. The grants of the European Research Council (ERC) are among the most significant and the most difficult to obtain European grants. Since 2007, they have been awarded to about 6.5 thousand scholars, including only 22 researchers from Poland.
"In the carefully planned experiments, we will examine the functioning of a particularly interesting part of the brain, responsible for processing of emotions: the amygdala. Most of all, we want to find out whether sharing of emotions – that is, emotions transmitted socially – engage the same groups of neurons as the non-social emotions. We will also make an attempt to find out whether social emotions of positive and negative nature are processed by the same neurons", Dr. Knapska explains.
The amygdala is a small structure shaped like an almond, located deep inside the brain. According to our knowledge, when the person is stimulated directly, the amygdala shows increased activity, which is particularly strong in the case of negative emotions, such as fear in the face of danger. It is known, however, that the amygdala is also involved in the control of social emotions, resulting from interactions with other people, who are also emotionally stimulated.
"Using optogenetics, we are able to control the activity of even very small fragments of the amygdala in rats. Step by step, we are planning to activate and shut down groups of neurons, most of them consisting of no more than several hundred nerve cells. Each time, we will check how the animal responds to emotions of another rat, present nearby, which has been appropriately stimulated emotionally", Dr. Knapska says.
Controlling strictly defined groups of neurons is possible only in rats that have been subjected to genetic modifications. As a result, in the cell membranes of selected neurons, photosensitive proteins emerge, which perform the role of ion channels. Before the experiment, a thin optical fiber is to be introduced into the animal's brain (rats tend to tolerate this microsurgical procedure very well). As the ion channels of the modified neurons are illuminated with light characterized by the appropriate wavelength, depending on their type they will either stimulate or inhibit neuron activity. Neuron responses to the light are almost immediate, making it easier to establish causal relationships between neuron group activity and the animal's behavior.
The works of Dr. Knapska's team are in the domain of basic science. Due to the optogenetic techniques applied, it would not be possible to conduct the same type of research in humans. However, understanding of the emotion processing in neurons of the amygdala in rats will also be of practical significance for understanding the mechanisms of various illnesses, such as autism or psychopathy, in which social communication skills are strongly affected. As the origin of these illnesses is partially similar in rats and in humans, knowledge obtained by Dr. Knapska's teams on the neurobiological foundations of processing of social stimuli in rats will probably eventually find its medical applications.
"Our results so far, which have allowed me to apply for the ERC grant, indicated initially that fear sensed by one rat, in fact, does activate the neuron systems in the amygdala of another animal. However, socially transmitted emotions are controlled by the brain in a very complex manner. Therefore, we are convinced that during further experiments, neuron responses will surely be surprising", Dr. Knapska says.
Provided by Nencki Institute of Experimental Biology
