Executive functioning

Dementia is the loss of function in multiple cognitive domains that occurs over a longer period of time, usually months to years. Diagnostic features include memory impairment and at least one of the following aphasia (deterioration of speech), apraxia (impaired ability to execute motor activities despite intact motor abilities, sensory function, and comprehension of the required task), agnosia (failure to recognize or identify objects despite intact sensory function), or disturbances in executive functioning.1... 

Cognitive function Executive function and mental processing such as understanding, perception, reasoning, language, and awareness. Executive function involves a long list of skills, but they can... 

Cognitive dysfunction is another symptom category that includes impaired attention, working memory, and executive function. 

The consequence is that data has to be maintained and consolidated in two systems. Because also some planning and production execution functions will stay in the ERP system, there is quite often the need for the planner to work with both systems and to gather information from both systems (e.g., customer order details, confirmations from production execution, which is handled in the ERP system) to make planning decisions. 

A PDE10A inhibitor may also have the potential to treat the cognitive symptoms of schizophrenia. The principal evidence for this claim is papaverine reversal of a PCP-induced deficit in the EDID-set shifting assay in rats [35]. This assay translates into human behavior in the form of the Wisconsin Card Sorting Test (WCST). EDID-set shifting is a test of executive function, a measure in which schizophrenics have a robust deficit. It has also been shown recently that papaverine is efficacious in the Novel Object Recognition cognition assay [36]. 

Dementia An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness. [NIH]... 

Kravaiiti, E., Dixon, T., Frith, C., Murray, R., and McGuire, P. (2005) Association of symptoms and executive function in schizophrenia and bipolar disorder. Schizophr. Res. 74, 221-231. 

Executive functions Impaired insight, judgement, planning... 

Figure la. Ascending activation from subcortical nuclei (see Fig. 2a) generates a stable platform of consciousness, essential for normal cognitive functions such as selective attention, learning and memory, and higher executive functions (Walker Ballard, 1998). 

The deficit of cortico-striatal innervation that is presumably responsible for reported losses of striatal glutamate uptake sites (Aparicio-Legarza et al., 1997 Simpson et al., 1992), is likely to contribute to the cognitive dysfunction of schizophrenia. These have been described as having similarities to the subcortical dementia (Pantelis et al., 1992) seen in a variety of neurodegenerative disorders disturbances of corticostriatal function are thought to underlie this pattern of cognitive deficits that include disturbances of attention, executive function and short-term memory. 

Neuropsychological impairments in mood disorders, particularly those of working memory and executive function, are the most convincing and objective demonstrations of an impairment of consciousness. Since these impairments do not correlate with the severity of the mood disturbance and persist upon recovery they are not simply epiphenomena of the mood disturbance but rather may index trait pathology in susceptible individuals. It has previously been argued that mood disturbance and neuropsychological impairment may result from disturbances in two different neurochemical systems, the serotonin (5-HT) system and the hypothalamic-pituitary-adrenal (HPA) axis, between which there is a close interaction (McAllister-Williams et al., 1998). 

Tryptophan depletion in healthy volunteers impairs the retrieval of learnt material (Park et al., 1994), an effect probably mediated through a selective impairment of episodic memory consolidation (Riedel et al., 1999 Schmitt et al., 2000). However, tryptophan depletion appears to have no effect on working memory (Riedel et al., 1999) and either no effect or an enhancement of tests of executive function (Park et al., 1994 Schmitt et al., 2000). Thus the abnormality in episodic memory in mood disorders could conceivably be related to an impairment in the 5-HT system, but such an impairment is unlikely to account for the abnormalities in working memory and executive function. Clearly then, changes in consciousness occurring in affective disorders are unlikely to be explainable on the basis of an abnormality in a single neurochemical system. 

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