Brain Region Governing Helping Behavior Identified

Summary: A new study found that the ventromedial prefrontal cortex (vmPFC) is crucial for prosocial behaviors. Researchers studied patients with brain damage and found that damage to the vmPFC reduced willingness to help others.

Understanding this brain region’s role could improve treatments for social interaction disorders and motivate global problem-solving efforts.

Key Facts:

  • Researchers pinpointed the ventromedial prefrontal cortex (vmPFC) as crucial for prosocial behaviors.
  • Study included patients with vmPFC damage, other brain damage, and healthy controls.
  • Damage to the vmPFC reduced willingness to help others and physical effort exerted.

Source: University of Birmingham

Our willingness to help others is governed by a specific brain region pinpointed by researchers in a study of patients with brain damage to that region. 

Learning about where in the brain ‘helping’ decisions are made is important for understanding how people might be motivated to tackle large global challenges, such as climate change, infectious disease and international conflict. It is also essential for finding new approaches to treating disorders of social interactions.  

This shows brains.
The results of the study clearly showed that the vmPFC was necessary for motivation to help others. Credit: Neuroscience News

The study, published in Nature Human Behaviour, was carried out by researchers at the University of Birmingham and the University of Oxford, and shows for the first time how a region called the ventromedial prefrontal cortex (vmPFC) has a critical role in helping, or ‘prosocial’ behaviours. 

Lead author Professor Patricia Lockwood said: “Prosocial behaviours are essential for addressing global challenges. Yet helping others is often effortful and humans are averse to effort. Understanding how effortful helping decisions are processed in the brain is extremely important.” 

In the study, the researchers focused on the vmPFC, a region located right at the front of the brain, which is known to be important for decision-making and other executive functions.

Previous studies using magnetic resonance imaging (MRI scanning) have linked the vmPFC to choices that involve a trade-off between the rewards available and the effort required to obtain rewards. However, these techniques cannot show whether a part of the brain is essential for these functions.  

Three groups of participants were recruited for the study. 25 patients had vmPFC damage, 15 patients had damage elsewhere in the brain, and 40 people were healthy age and gender-matched control participants. These groups allowed the researchers to test the impact of damage to vmPFC specifically. 

Each participant attended an experiment where they met another person anonymously. They then completed a decision-making task that measured how willing they were to exert physical effort (squeezing a grip force device) to earn rewards (bonus money) for themselves and for the other person. 

By enabling participants to meet – but not see – the person they were ‘working’ for in advance, researchers were able to convey the sense that participants’ efforts would have real consequences, but hide any information about the other person that could affect decision-making. 

Each choice the participants made varied in how much bonus money for them or the other person was available, and how much force they would have to exert to obtain the reward. This allowed the researchers to measure the impact of reward and effort separately, and to use advanced mathematical modelling to precisely quantify people’s motivation.  

The results of the study clearly showed that the vmPFC was necessary for motivation to help others. Patients with vmPFC damage were less willing to choose to help others, exerted less force on even after they did decide to help, and earned less money to help others compared to the control groups. 

In a further step, the researchers used a technique called lesion symptom mapping which enabled them to identify even more specific subregions of the vmPFC where damage made people particularly antisocial and unwilling to exert effort for the other person. Surprisingly, damage to a nearby but different subregion made people relatively more willing to help. 

Co-lead author Dr Jo Cutler said: “As well as better understanding prosocial motivation, this study could also help us to develop new treatments for clinical disorders such as psychopathy, where understanding the underlying neural mechanisms can give us new insights into how to treat these conditions.” 

“This region of the brain is particularly interesting because we know that it undergoes late development in teenagers, and also changes as we get older,” added Professor Lockwood.

“It will be really interesting to see whether this area of the brain can also be influenced by education – can we learn to be better at helping others?” 

About this behavioral neuroscience research news

Author: Beck Lockwood
Source: University of Birmingham
Contact: Beck Lockwood – University of Birmingham
Image: The image is credited to Neuroscience News

Original Research: Open access.
Human ventromedial prefrontal cortex is necessary for prosocial motivation” by Patricia Lockwood et al. Nature Human Behavior


Abstract

Human ventromedial prefrontal cortex is necessary for prosocial motivation

Ventromedial prefrontal cortex (vmPFC) is vital for decision-making. Functional neuroimaging links vmPFC to processing rewards and effort, while parallel work suggests vmPFC involvement in prosocial behaviour.

However, the necessity of vmPFC for these functions is unknown. Patients with rare focal vmPFC lesions (n = 25), patients with lesions elsewhere (n = 15) and healthy controls (n = 40) chose between rest and exerting effort to earn rewards for themselves or another person. vmPFC damage decreased prosociality across behavioural and computational measures.

vmPFC patients earned less, discounted rewards by effort more, and exerted less force when another person benefited, compared to both control groups. Voxel-based lesion mapping revealed dissociations between vmPFC subregions.

While medial damage led to antisocial behaviour, lateral damage increased prosocial behaviour relative to patients with damage elsewhere. vmPFC patients also showed reduced effort sensitivity overall, but reward sensitivity was limited to specific subregions.

These results reveal multiple causal contributions of vmPFC to prosocial behaviour, effort and reward.

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