Lower levels of information processing in some areas of the brain suggest cognition is impaired. For example, reduced processing in the ventral striatum is associated with negative symptoms.
Metarepresentation is the cognitive ability to reflect on thoughts and behaviour (Frith). This dysfunction disrupts our ability to recognise our thoughts as our own - could lead to the sensation of hearing voices (hallucination) and experience of having thoughts placed in the mind by others (thought insertion, a delusion).
Frith also identified dysfunction of central control as a way to explain speech poverty - central control being the cognitive ability to suppress automatic responses while performing deliberate actions. People with schizophrenia experience derailment of thoughts because each word triggers automatic associations that they cannot suppress.
