Schizophrenia is an illness affecting feelings and behaviour, and has long been considered to originate from abnormalities in the formation of associative memories. However, a new study published in Molecular Psychiatry, suggests that only a specific component of associative memories is affected in schizophrenia.
Schizophrenia is a mental disorder characterized by abnormal social behavior and failure to understand what is real. Common symptoms include false beliefs, unclear or confused thinking, hearing voices that others do not, reduced social engagement and emotional expression, and a lack of motivation. People with schizophrenia often have additional mental health problems such as anxiety disorders, major depressive illness, or substance use disorders. Symptoms typically come on gradually, begin in young adulthood, and last a long time
Associative memory formation refers to how humans and animals modify behaviour based on a stimulus and a response, and subsequently remember that two different events happen or occur together.
In the study, researchers at Cardiff University extracted genetic information from rats relating to three memory components of associative fear learning: consolidation, retrieval and extinction. Comparing this information with the genetic variants found in around 12,000 patients with schizophrenia, the researchers demonstrated that deletions and duplications in sections of DNA occurred in regions containing genes involved in extinguishing fearful memories.
Consolidation refers to the process in which information is stored in various parts of the brain, and retrieval refers to the process whereby this information can be recalled as memories. Extinction, on the other hand, is the gradual weakening of a behaviour in response to a particular stimulus.
“Extinction learning is required for updating associative memories to correct previous beliefs” said Nicholas Clifton, a PhD student from the University’s Neuroscience and Mental Health Research Institute (NMHRI) who led the study. “The findings suggest that delusions and false beliefs characteristic of schizophrenia might be due to genetic variants affecting the functioning of genes responsible for extinction learning”.
These results help to guide future schizophrenia research to this particular component of learning and may facilitate the development of novel therapies.
Credit: Cardiff University