Deficits in access consciousness, integrative function, and consequent autonoetic thinking in schizophrenia.

Alterations within consciousness in schizophrenia can be evidenced by impediments in self-awareness and loss of agency. Ned Block's definition of access consciousness is applied in order to further delineate cognitive deficits involving reflective thought and autonoetic thinking in persons with schizophrenia. Current theories on the nature and functioning of consciousness are discussed, which include Global Workspace Theory and metarepresentational characterizations. These describe a recursive, integrative quality to consciousness, contributed to by the functions of access consciousness, that is relevant in examining cognitive deficits in schizophrenia. The integrative deficit that is described as operating in conscious process involves a failure to incorporate prior outputs from a separate cognitive task and integrate these into a novel working schema. The alterations in access consciousness in persons with schizophrenia appear to be a consequence of disrupted integrative cognitive functions. An anteceding problem with cortical circuits involving integrative functions related to access consciousness is therefore hypothesized to manifest as subsequent cognitive dysfunction that leads to symptoms of schizophrenia. Constitutive failures to integrate information in schizophrenia could lead to an inability to create experiential unity and manage content in autonoetic consciousness. Some of the aberrant reasoning manifested by persons with schizophrenia, including problems with hierarchical relational reasoning, model-based-learning, J-con, ipseity, and source monitoring, could also reflect alterations in access consciousness, and their investigation offers additional approaches for scientific inquiry.

Variant Creutzfeldt-Jakob Disease Presenting as New-onset Psychosis.

The case of a patient with a first presentation psychotic episode secondary to variant Creutzfeldt-Jakob Disease (vCJD) is presented. While psychiatric symptoms are considered a prominent feature of vCJD, they may precede characteristic neurological symptoms, which can delay diagnosis. The psychotic symptoms in this case differed in quality from typical psychotic presentations, which could have helped with earlier diagnosis. The patient's symptomatology suggested that errors in cognition and perception were largely contributing to his psychiatric symptoms. These errors appeared to be the result of prion destruction of relevant brain structures that may either be directly or secondarily involved in psychiatric disorders. The findings in this case can help elucidate how vCJD symptoms deviate from established guidelines for diagnosing primary psychiatric disorders.

Thought disorder in schizophrenia: impairment in contextual processing via integrative failures in cognition.

Formal thought disorder is a critical dysfunction in schizophrenia whose cause remains uncertain, but whose explanation may greatly further our understanding of the disease. Thought disorder in patients with schizophrenia has been hypothesized to involve a disturbance in the internal representation of context. Positive symptoms of schizophrenia attributable to thought disorder display a lack of organization that may be accounted for by an absence of normal contextual processing occurring within the operations of the executive system. But the precise nature and pervasiveness of the deficient cognitive operation remain undistinguished. It is proposed here that the assimilatory functions of the brain appear to lack the ability to perform a particular type of integrative operation when presented with heterogeneous information. This deficit involves committing cognitive misattributions through a confusion of mental terms via a process in thought analogous to a linguistic failure to correctly interpret deictic referents. Both proposed deficits in mental deixis and analogous "metarepresentational" deficits in schizophrenia potentially involve a failure to draw information for a conclusion from a separate framework of relations in integrative fashion. These deficits appear to involve a failure to take an interpreted piece of information as an output from a particular mental task and incorporate it into a new operational scheme, and a central attribute to the deficit is that there is a loss of an effective or adequate integration of separate strata of information. Potential neurobiological correlates to such a system based on current knowledge about schizophrenia neurocircuitry, as well as implications for testing, are also discussed.