Perceptual Processing in Psychosis
Research type
Research Study
Full title
Identifying Neural Signatures of Perceptual Processing in Emerging Psychosis: A Multi-Modal Imaging Approach
IRAS ID
277200
Contact name
Lars Muckli
Contact email
Sponsor organisation
NHS Greater Glasgow & Clyde (NHS GGC)
Duration of Study in the UK
3 years, 11 months, 31 days
Research summary
Psychotic disorders, such as Schizophrenia (ScZ), are debilitating mental illnesses with a prevalence rate of approximately 1%, resulting in enormous economic and social costs. Cognitive deficits, such as difficulties in attention, perception and memory, are considered a core component of psychosis as these predict the clinical outcome better than the overt signs of psychosis. However, although pharmacological treatments have been shown to improve the psychotic symptoms of ScZ, such treatments are mostly ineffective in treating cognitive impairments. Therefore, gaining further insights into the origins of cognitive deficits may be important for developing more effective interventions for psychosis.
In the proposed project, we will apply a new framework towards understanding cognitive impairments in psychosis that is based on current models of how the brain processes and transmits information. Recent evidence suggests two broad classes of processes can be distinguished that seem to support different functions and are characterized by distinct biological correlates: 1) a “feedforward” mode that transmits information based upon the characteristics of the incoming stimulus and 2) a “feedback” mode that is governed by the internal activity of the brain, such as expectations and predictions about events.
Until now, distinguishing these different brain modes using non-invasive brain imaging, such as functional magnetic resonance imaging (fMRI) or Magnetoencephalography (MEG), has been challenging. However, novel evidence from basic anatomy and biology has suggested that distinct brain waves at different frequencies as well as particular brain channels may support these different brain modes. As a result, we will attempt for the first time to identify these brain modes through using state-of-the-art brain imaging and thus gain a new understanding of how the brain transmits information and how these processes might contribute to established psychosis as well as those who are at-Risk for the development of psychosis.Lay summary of study results:
The brain constantly tries to predict what it will sense next. It builds these predictions from past experiences and updates them when they are wrong. The difference between what is expected and what is sensed is called a prediction error. These prediction processes may work differently in Schizophrenia. This can lead to unusual perceptions, such as hallucinations, and false beliefs, known as delusions. One idea is that the brain does not handle prediction errors correctly. Researchers often study this using sounds. When a different sound appears in a series of repeated tones, the brain shows a response called mismatch negativity (MMN). This response reflects the brain detecting a change from what it expected. People with Schizophrenia often show a weaker MMN response than healthy individuals. This makes MMN a useful biological marker of psychosis. Most MMN studies use methods that measure timing very well but not precise brain location. This limits understanding of where these processes happen in the brain. New imaging methods can help address this gap. High-resolution brain scanning, such as 7T fMRI, can show activity in very small brain areas. It may help distinguish between signals that carry predictions and those that carry prediction errors. This could improve understanding of how brain circuits are altered in early psychosis. When we scanned individuals with Schizophrenia and a control group, we found that unexpected sounds produced stronger brain responses than repeated sounds, in the auditory areas of the brain. This shows the brain detects changes from what it expects. The brain’s response to unexpected inputs depends, however, on where attention is directed, and this effect differs between people with and without Schizophrenia. Overall, this research aims to better explain how changes in predictive brain processes relate to symptoms of Schizophrenia.REC name
West of Scotland REC 4
REC reference
20/WS/0106
Date of REC Opinion
2 Nov 2020
REC opinion
Further Information Favourable Opinion