Other cognitive tasks

In a PET study of the Tower of London task. Baker et al. (1996) observed activation in distributed network of cortical areas incorporating prefrontal, cingulate, premotor, parietal and occipital cortices. Activation in corresponding areas has been observed in visuospatial working memory task with the exception of the rostral prefrontal cortex. The authors therefore suggest that this area may be identified with the executive components of planning comprising response selection and evaluation. 

Osmon suggests that the task, requiring the participant to utilize a rule, must be kept in working memory (dorsolateral prefrontal cortex) to respond quickly to a stimulus. 

Volz et al (1997) studied brain activation during the Wisconsin Card Sorting Test (WCST) by using functional MRI. In healthy volunteers WCST stimulation resulted 

Posner and Raichle (1994) When subjects were asked to look for animal names as they read a series of nouns, strong PET activation appeared in the anterior cingulate gyrus. Moreover, the activation became stronger as the number of targets in the list of nouns increased. In addition, there is a reduction in such activation as the task becomes automated with practice. This made the authors think that the area served as an attention system. 

Villringer etal (1997) performed simultaneously near-infrared spectroscopy (NIRS) and positron emissions tomography (PET) in five healthy subjects during rest and during performance of a calculation task and a Stroop task. A statistically significant correlation between changes in CBF and changes in [total-Hb] was found. 

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The IMAS technique described above is useful, in that it addresses aspects of operational skills, that is, diagnostic and problem solving abilities, that are not covered by other techniques. To that extent it can be regarded as a method of cognitive task analysis. It is not essential to use a computer program to obtain useful results. The mental models produced by IMAS can be elicited by pencil and paper methods. Nevertheless interpretation and application of the results require some expertise. 

Few studies have examined the effects of benzodiazepines on other cognitive abilities. Rusted et al.170 reported that 5 and 10 mg diazepam impaired performance on a logical reasoning test, but had no effect on a mental rotation task. Judd et al.178 found that 30 mg flurazepam, but not 15 mg midazolam, impaired arithmetic (addition) abilities the day after drug administration. In contrast, flurazepam had no effect on reading comprehension. 

One means of examining the effect of sleep deprivation on effort is to ask sleep-deprived individuals to estimate how much effort they put into a task that they just completed. Although several sleep deprivation studies have used this approach, the results remains unclear. Some studies have reported decreased performance but increased effort on cognitive tasks (45), while other studies have seen an increased effort associated with no change in performance (52,53). Yet another study examining effort on cognitive tasks found no change in... 

However there are other interpretations of existing evidence. Cognitive decline may be an early psychological manifestation of the experiences that constitute psychosis. Being preoccupied with the internal world of incipient psychosis is likely to interfere with someone s ability to perform certain cognitive tasks. Another explanation is that deficits in the ability to reason and communicate may predispose people to the development of psychosis. The possibilities are numerous and the nature of the relation is unlikely to be simple. 

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