The neurotransmitter dopamine is often known for its role in brain networks that regulate pleasure and reward.
But many individuals with disorders that affect the dopamine system, akin to Parkinson's disease or schizophrenia, also Struggles with social skills. These include recognizing or understanding the emotions and mental states of others, which scientists call “theory of mind.”
These social difficulties can significantly affect the social relationships and quality of lifetime of those affected. However, it’s unclear whether these challenges are directly attributable to the dopamine imbalance or Other factors that occur together. with these errors.
Now our recent research, Published in PLOS Biology., shows that dopamine deficiency directly causes social difficulties. This suggests that dopamine-based drugs may at some point also help treat social difficulties in disorders with dopamine imbalance.
People with Parkinson's disease often Show fewer facial expressions. in comparison with healthy individuals. Others may respond in negative ways – eventually victims withdraw from social situations altogether. And individuals who have been socially withdrawn for a very long time may struggle more with social interactions because they don't get the possibility to practice (remember how hard it was to get back into the social world after the lockdown?).
This is one possible reason individuals with Parkinson's could have difficulty understanding others.
However, this will not be the one explanation. Linked to Parkinson's. Death of dopamine neurons So some scientists have suspected that dopamine plays a key role in our ability to grasp others.
Experimental model
Our latest study tested this latter explanation in 33 healthy individuals. We did this by giving people a drug that was intended to cut back dopamine levels in certain parts of the brain. Blocking receptors to which the neurotransmitter is attached.
We then evaluated their theory of mind abilities using an adaptation of a. A classical scientific experiment. In the unique study that introduced this experiment, the authors observed that when people were shown Short videos Of the interactionist triangle, they easily attribute social roles and mental states to moving objects.
We used similar videos. There were some “state of mind interactions”, during which one triangle acts on or causes a mind-set in one other triangle, akin to “amazing”. We also had control videos, which included easy, action-oriented interactions, akin to one triangle after one other. It's a terrific method to investigate people's ability to grasp others since you exclude other aspects which may affect participants' performance, akin to how they process language or faces.
Bianca Schuster, CC BY-SA
All participants accomplished the test twice, once after taking the dopamine pill, and once after taking a placebo pill. The order during which they received the interventions was randomized.
We found that taking the drug reduced participants' ability to accurately label each varieties of triangle videos compared to placebo. This suggests that dopamine is crucial for interpreting social interactions, whether or not they involve perceiving mental states (akin to surprise) or not (following).
Interestingly, participants who demonstrated a lower ability to accurately attribute mental states to triangles were also more prone to struggle with recognizing emotions (akin to is measured by another test. Showing a human figure walking through offended, sad and blissful emotional states after receiving the drug.
This suggests that there could also be a typical mechanism underlying each emotion recognition and theory of mind within the brain. It is feasible that dopamine regulates these abilities through our reward network, motivating us to hunt down things that make us feel good, and to repeat those behaviors. In a social context, dopamine might help us pay particular attention to subtle social cues communicated by other people.
Our results suggest that individuals with dopamine imbalances could have difficulty adequately recognizing social cues communicated by others. But we also explored one other possibility. In addition to its role in reward processing, dopamine is understood to play a vital role in motivation. This is why the most important symptoms of Parkinson's disease include difficulties on this domain, akin to problems initiating movement.
Previous research suggests that we use (representations of) our own movements to grasp the movements of others. The way people move is commonly a transparent indication of their emotions and mental states. If we’re sad, we normally walk slower and if we’re blissful, we walk faster.
We showed that individuals were higher at interpreting triangle movements when the triangles rotated in a way that resembled their very own movements. This suggests that individuals who struggle with movement may find it difficult to interpret the movements of others, and due to this fact their mental states.
That said, the drug we utilized in the study made them move more slowly. But this didn’t affect the participants' ability to interpret the triangular videos.
This is because throughout life, we associate our own movements with certain mental states and use these patterns to grasp the movements of others. This implies that even when someone gives you a drug that temporarily changes your actions, you continue to use your long-held patterns to interpret other people's actions.
But it's possible that within the later stages of Parkinson's, long-term dopamine deficiency can alter their stored movement patterns – making them difficult to interpret in others.
Possible treatment
We consider these recent insights represent a vital step forward in our understanding of the neurochemical basis of social cognition.
Our findings might also help us higher understand the social impact of dopaminergic drugs, that are prescribed to hundreds of thousands of individuals day-after-day, including individuals with Parkinson's and schizophrenia. For example, individuals with schizophrenia have an excessive amount of dopamine in certain parts of the brain. And research shows it may. Lead issues With understanding of others – with The equilibrium level is maximum. What we didn't know before is that dopamine blockers that are supposed to treat delusions and hallucinations can even help with cognitive abilities.
It is hoped that our study will pave the way in which for future studies aimed toward developing recent therapeutic interventions for individuals who find it obscure others. In addition to individuals with Parkinson's and schizophrenia, it could be useful for a variety of other conditions affected by dopamine imbalances, e.g. Huntington's disease or Tourette's syndrome.