An Ecological Approach to Planning Dysfunction: Script Execution (original) (raw)
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Selective Impairments in Managerial Knowledge Following Pre-Frontal Cortex Damage
Cortex, 1995
Script generation was investigated in patients with lesions in the prefrontal (n = 9) and posterior (n = 8) cortical regions and in normal subjects (n = 16). Three different activities ranging in degree of familiarity were studied. Frontal patients did not differ from patients with posterior lesion and Normal subjects in the number of actions evoked, mean evocation time, or centrality. Impairments in script information processing were observed only in patients with prefrontal lesions, and for the three types of scripts. Specifically these patients made errors in ordering actions in the correct temporal sequence, failed to close scripts and to remain within the stated boundaries, and made deviant estimates of action importance. The results suggest that pre-frontal cortical lesions provoke a selective impairment in managerial knowledge ) that may contribute to difficulties in the formulation and execution of plans.
Action Planning in a Virtual Context after Prefrontal Cortex Damage
Patients with frontal lobe lesions are known to encounter severe problems in the organisation of their behaviour in everyday life. Script generation tasks assess the subject’s conceptual ability to formulate and evaluate a coherent and structured plan of action. In the present study, we investigated to what extent neuropsychological deficits observed at the conceptual level of action knowledge lead to impairments in action execution. We examined seven patients with prefrontal cortex damage and sixteen normal subjects. Subjects were first asked to verbally formulate a plan of action and then to use this knowledge for ‘executing’ the actions in a virtual 3-dimensional interactive apartment presented on a computer screen. The results indicated that the presence of the realistic context improved patients’ performance. However, specific impairments were observed in patients in the execution condition, namely actions slips, omissions, failure in initiating actions and purposeless displacements. Moreover, an analysis of planning time showed that, differently of the patients group, normal subjects spent more time during plan execution as compared to plan generation. These results suggest that after a frontal lobe lesion a defective formulation of a routine plan might affect the execution of the corresponding course of actions.
Dissociating the role of the medial and lateral anterior prefrontal cortex in human planning
Proceedings of the National Academy of Sciences, 2000
The anterior prefrontal cortex is known to subserve higher cognitive functions such as task management and planning. Less is known, however, about the functional specialization of this cortical region in humans. Using functional MRI, we report a double dissociation: the medial anterior prefrontal cortex, in association with the ventral striatum, was engaged preferentially when subjects executed tasks in sequences that were expected, whereas the polar prefrontal cortex, in association with the dorsolateral striatum, was involved preferentially when subjects performed tasks in sequences that were contingent on unpredictable events. These results parallel the functional segregation previously described between the medial and lateral premotor cortex underlying planned and contingent motor control and extend this division to the anterior prefrontal cortex, when task management and planning are required. Thus, our findings support the assumption that common frontal organizational principles underlie motor and higher executive functions in humans.
Script Generation Following Frontal and Parietal Lesions
Journal of Clinical and Experimental Neuropsychology, 2004
The purpose of this investigation was to distinguish putative effects of parietal lobe lesions on script generation, in distinction from the better known and established effects of frontal lobe lesions. Nine patients, most with excised parietal lesions, were compared to nine age, gender and education matched normal participants. Eleven patients with excised tumors of the frontal lobe were compared to twelve age, gender and education matched normal subjects. Participants were requested to generate, out loud, scripts corresponding to everyday activities. Half the scripts were relatively more demanding with respect to temporal representation (understanding the time line of events) and the other half with respect to spatial representation (understanding the layout of the actions in space). These two conditions were further broken down into conditions of high and low demands on working memory (reciting the scripts backwards versus forward). The frontal lobe patients enunciated significantly fewer actions overall. They were also significantly more impaired than the normal participants on all tasks with high demands on working memory, and more often, high temporal demands (sequencing and perseverative errors). The parietal lobe patients had significant difficulty in sequencing in all conditions, and manifested no perseveration. Though script generation tasks have been primarily associated with frontal lobe function until now, consideration should be given to the type of activity being scripted as a function of relative demands on spatial or temporal representation, as well as working memory, and the contributions of other lobes ought to be taken into consideration.
1994
This paper presents an AI model of integrated planning and reaction based on neuropsychological theories of similar human behavior. The model forges a link between frontal lobe models and AI planning systems that can improve our understanding of situated planning through a combined perspective. This paper first sets the frontal lobes in context, and then summarizes the frontal lobe theories upon which the model is based. Those theories are then synthesized into a single computational model for an artificial frontal lobe, and the components are discussed from both neuropsychological and AI perspectives. The paper concludes with a discussion of evaluation issues.
VIRTUAL PLANNING IN PATIENTS WITH FRONTAL LOBE LESIONS
The VIrtual Planning Test (VIP) was developed to investigate the planning and organisational abilities of 25 patients with frontal lobe neurosurgical lesions, comparing their performance with 25 matched control subjects. The task, presented in the form of a board game, simulates planning and execution of a set of target activities that have to take place over a four day period, involving those that are either preparatory for a fictional " trip " abroad, or those that relate to the subject's current environment (context). The frontal lobe patients were impaired overall, tending to select inappropriate activities associated with their current context and showing greater impairment on subtasks requiring only one, rather than two, preparatory acts. The findings are discussed in terms of the validity of the VIP test in identifying executive functioning impairment and the degree to which the pattern of deficits are consistent with neuropsychological models of executive function.
Disorders in planning and strategy application in frontal lobe lesion patients
Brain and Cognition, 2007
The aim of this study was to investigate deWcits in planning ability using an adapted version of the ModiWed Six Elements Test, from the Behavioral . Rio de Janeiro: Cognição]. Subjects were left-and right-frontal lobe lesion patients. Other measures of executive dysfunctions used were verbal Xuency, the Wisconsin Card Sorting Test, and the Trail Making Test. These other instruments were sensitive to detect executive deWcits in the left frontal lobe lesion group, except the Wisconsin Card Sorting Test, which showed impairment only for the frontal lobe lesion group as a whole. The ModiWed Six Elements Test detected planning disorders in left frontal lobe lesion patients. The deWcit of these patients was due to a greater likelihood to break the rules of the task, that is, in plan-following processes, rather than in planning the strategic approach to solve it.