Computer model sheds light on how brain circuits might be altered in psychiatric diseases

Scientists have built a computer ‘brain circuit’, or artificial neural network, that mirrors human decision-making processes and sheds light on how circuits might be altered in psychiatric diseases, a new study published today in eLife reports.

The model identifies a potential mechanism for the impaired decision making that is commonly seen in schizophrenia, involving the reduced activity of molecules in the brain called NDMA receptors. These results provide new insight that may inform the development of future treatments for neuropsychiatric conditions.

A major challenge in psychiatry is to relate changes that occur at nerve synapses in the brain to the cognitive processes that cause symptoms of disorders such as schizophrenia. Computational modelling of brain circuits can fill in these gaps. By altering the circuit model at the synapse level, you can make predictions of nerve activity and behaviours, and then test these experimentally.”

Dr. Sean Cavanagh, lead author, MBPhD student at the UCL Queen Square Institute of Neurology, London, UK

The team built a model that reproduces how the brain accumulates evidence and makes a decision. The types of decisions they were interested in were those that involve combining multiple pieces of information. For example, when deciding about where to go on holiday, we must combine information about many factors including the cost, weather and cultural experience. Initially, the team wanted to see whether their computer model showed the same decision-making bias that healthy humans show on these sorts of choices, called the ‘pro-variance bias’. This describes how humans tend to choose options with more variable evidence. For example, when planning a holiday and facing two options, people generally tend to prefer a holiday which is very appealing in one attribute but less so in another (expensive price,