56 resultados para cognitive task analysis
Resumo:
Coordinated eye and head movements simultaneously occur to scan the visual world for relevant targets. However, measuring both eye and head movements in experiments allowing natural head movements may be challenging. This paper provides an approach to study eye-head coordination: First, we demonstra- te the capabilities and limits of the eye-head tracking system used, and compare it to other technologies. Second, a beha- vioral task is introduced to invoke eye-head coordination. Third, a method is introduced to reconstruct signal loss in video- based oculography caused by cornea reflection artifacts in order to extend the tracking range. Finally, parameters of eye- head coordination are identified using EHCA (eye-head co- ordination analyzer), a MATLAB software which was developed to analyze eye-head shifts. To demonstrate the capabilities of the approach, a study with 11 healthy subjects was performed to investigate motion behavior. The approach presented here is discussed as an instrument to explore eye-head coordination, which may lead to further insights into attentional and motor symptoms of certain neurological or psychiatric diseases, e.g., schizophrenia.
Resumo:
Brian electric activity is viewed as sequences of momentary maps of potential distribution. Frequency-domain source modeling, estimation of the complexity of the trajectory of the mapped brain field distributions in state space, and microstate parsing were used as analysis tools. Input-presentation as well as task-free (spontaneous thought) data collection paradigms were employed. We found: Alpha EEG field strength is more affected by visualizing mentation than by abstract mentation, both input-driven as well as self-generated. There are different neuronal populations and brain locations of the electric generators for different temporal frequencies of the brain field. Different alpha frequencies execute different brain functions as revealed by canonical correlations with mentation profiles. Different modes of mentation engage the same temporal frequencies at different brain locations. The basic structure of alpha electric fields implies inhomogeneity over time — alpha consists of concatenated global microstates in the sub-second range, characterized by quasi-stable field topographies, and rapid transitions between the microstates. In general, brain activity is strongly discontinuous, indicating that parsing into field landscape-defined microstates is appropriate. Different modes of spontaneous and induced mentation are associated with different brain electric microstates; these are proposed as candidates for psychophysiological ``atoms of thought''.
Resumo:
These data result from an investigation examining the interplay between dyadic rapport and consequential behavior-mirroring. Participants responded to a variety of interpersonally-focused pretest measures prior to their engagement in videotaped interdependent tasks (coded for interactional synchrony using Motion Energy Analysis [17,18]). A post-task evaluation of rapport and other related constructs followed each exchange. Four studies shared these same dependent measures, but asked distinct questions: Study 1 (Ndyad = 38) explored the influence of perceived responsibility and gender-specificity of the task; Study 2 (Ndyad = 51) focused on dyad sex-makeup; Studies 3 (Ndyad = 41) and 4 (Ndyad = 63) examined cognitive load impacts on the interactions. Versions of the data are structured with both individual and dyad as the unit of analysis. Our data possess strong reuse potential for theorists interested in dyadic processes and are especially pertinent to questions about dyad agreement and interpersonal perception / behavior association relationships.
Resumo:
In this study we investigated whether synesthetic color experiences have similar effects as real colors in cognitive conflict adaptation. We tested 24 synesthetes and two yoke-matched control groups in a task-switching experiment that involved regular switches between three simple decision tasks (a color decision, a form decision, and a size decision). In most of the trials the stimuli were univalent, that is, specific for each task. However, occasionally, black graphemes were presented for the size decisions and we tested whether they would trigger synesthetic color experiences and thus, turn them into bivalent stimuli. The results confirmed this expectation. We were also interested in their effect for subsequent performance (i.e., the bivalency effect). The results showed that for synesthetic colors the bivalency effect was not as pronounced as for real colors. The latter result may be related to differences between synesthetes and controls in coping with color conflict.
Resumo:
Randomised controlled trials (RCTs) of psychotherapeutic interventions assume that specific techniques are used in treatments, which are responsible for changes in the client's symptoms. This assumption also holds true for meta-analyses, where evidence for specific interventions and techniques is compiled. However, it has also been argued that different treatments share important techniques and that an upcoming consensus about useful treatment strategies is leading to a greater integration of treatments. This makes assumptions about the effectiveness of specific interventions ingredients questionable if the shared (common) techniques are more often used in interventions than are the unique techniques. This study investigated the unique or shared techniques in RCTs of cognitive-behavioural therapy (CBT) and short-term psychodynamic psychotherapy (STPP). Psychotherapeutic techniques were coded from 42 masked treatment descriptions of RCTs in the field of depression (1979-2010). CBT techniques were often used in studies identified as either CBT or STPP. However, STPP techniques were only used in STPP-identified studies. Empirical clustering of treatment descriptions did not confirm the original distinction of CBT versus STPP, but instead showed substantial heterogeneity within both approaches. Extraction of psychotherapeutic techniques from the treatment descriptions is feasible and could be used as a content-based approach to classify treatments in systematic reviews and meta-analyses.
Resumo:
Duchenne muscular dystrophy (DMD) is a hereditary X-linked recessive disorder affecting the synthesis of dystrophin, a protein essential for structural stability in muscle. Dystrophin also occurs in the central nervous system, particularly in the neocortex, hippocampus and cerebellum. Quantitative metabolic analysis by localized (1) H MRS was performed in the cerebellum (12 patients and 15 controls) and a temporo-parietal location (eight patients and 15 controls) in patients with DMD and healthy controls to investigate possible metabolic differences. In addition, the site of individual mutations on the dystrophin gene was analyzed and neuropsychological cognitive functions were examined. Cognitive deficits in the patient group were found in line with earlier investigations, mainly concerning verbal short-term memory, visuo-spatial long-term memory and verbal fluency, but also the full-scale IQ. Causal mutations were identified in all patients with DMD. Quantitative MRS showed consistent choline deficits, in both cerebellar white matter and temporo-parietal cortex, as well as small, but significant, metabolic abnormalities for glutamate and total N-acetyl compounds in the temporo-parietal region. Compartment water analysis did not reveal any abnormalities. In healthy subjects, choline levels were age related in the cerebellum. The choline deficit contrasts with earlier findings in DMD, where a surplus of choline was postulated for the cerebellum. In patients, total N-acetyl compounds in the temporo-parietal region were related to verbal IQ and verbal short-term memory. However, choline, the putative main metabolic abnormality, was not found to be associated with cognitive deficits. Furthermore, in contrast with the cognitive performance, the metabolic brain composition did not depend significantly on whether or not gene mutations concerned the expression of the dystrophin isoform Dp140, leading to the conclusion that the effect of the missing Dp140 isoform on cognitive performance is not mediated through the observed metabolite composition, or is caused by local effects beyond the resolution accessible to MRS investigations.
Resumo:
Mutations in the dystrophin gene have long been recognised as a cause of mental retardation. However, for reasons that are unclear, some boys with dystrophin mutations do not show general cognitive deficits. To investigate the relationship between dystrophin mutations and cognition, the general intellectual abilities of a group of 25 boys with genetically confirmed Duchenne muscular dystrophy were evaluated. Furthermore, a subgroup underwent additional detailed neuropsychological assessment. The results showed a mean full scale intelligence quotient (IQ) of 88 (standard deviation 24). Patients performed very poorly on various neuropsychological tests, including arithmetics, digit span tests and verbal fluency. No simple relationship between dystrophin mutations and cognitive functioning could be detected. However, our analysis revealed that patients who lack the dystrophin isoform Dp140 have significantly greater cognitive problems.
Resumo:
Medical-forensic examination of sexual assault victims and alleged offenders is a common task of many forensic institutes. In the current study, the results from samples taken at the Institute of Legal Medicine, Hanover Medical School, during a period from 2005 to 2007 were retrospectively evaluated. In total, 292 victims (283 females and nine males) and 88 suspects were examined. At the time of the assault, 41.8% of the victims and 43.2% of the alleged perpetrators were under the influence of alcohol. Injuries were found in 84.9% of the victims and 39.8% of the suspects. Thirty victims (10.3%) reported having been choked or strangled. Cytology was performed in 218 victims. In 81 cases (38.0%), sperm could be detected in vaginal swabs up to 3 days post-assault. In seven (18.9%) out of 37 anal samples, evidence of sperm could be found 24 h post-assault. None of 22 oral samples was positive for sperm. Out of 301 sexual assault cases, 171 could be proved by means of medical-forensic examination. In summary, our evaluation shows that an early medical-forensic examination of both victim and suspect can secure numerous medical findings. Furthermore, persons intoxicated by alcohol, handicapped persons and persons with psychiatric disorders are more vulnerable to become a sexual assault victim.
Resumo:
The Default Mode Network (DMN) is a higher order functional neural network that displays activation during passive rest and deactivation during many types of cognitive tasks. Accordingly, the DMN is viewed to represent the neural correlate of internally-generated self-referential cognition. This hypothesis implies that the DMN requires the involvement of cognitive processes, like declarative memory. The present study thus examines the spatial and functional convergence of the DMN and the semantic memory system. Using an active block-design functional Magnetic Resonance Imaging (fMRI) paradigm and Independent Component Analysis (ICA), we trace the DMN and fMRI signal changes evoked by semantic, phonological and perceptual decision tasks upon visually-presented words. Our findings show less deactivation during semantic compared to the two non-semantic tasks for the entire DMN unit and within left-hemispheric DMN regions, i.e., the dorsal medial prefrontal cortex, the anterior cingulate cortex, the retrosplenial cortex, the angular gyrus, the middle temporal gyrus and the anterior temporal region, as well as the right cerebellum. These results demonstrate that well-known semantic regions are spatially and functionally involved in the DMN. The present study further supports the hypothesis of the DMN as an internal mentation system that involves declarative memory functions.
Core networks for visual-concrete and abstract thought content: a brain electric microstate analysis
Resumo:
Commonality of activation of spontaneously forming and stimulus-induced mental representations is an often made but rarely tested assumption in neuroscience. In a conjunction analysis of two earlier studies, brain electric activity during visual-concrete and abstract thoughts was studied. The conditions were: in study 1, spontaneous stimulus-independent thinking (post-hoc, visual imagery or abstract thought were identified); in study 2, reading of single nouns ranking high or low on a visual imagery scale. In both studies, subjects' tasks were similar: when prompted, they had to recall the last thought (study 1) or the last word (study 2). In both studies, subjects had no instruction to classify or to visually imagine their thoughts, and accordingly were not aware of the studies' aim. Brain electric data were analyzed into functional topographic brain images (using LORETA) of the last microstate before the prompt (study 1) and of the word-type discriminating event-related microstate after word onset (study 2). Conjunction analysis across the two studies yielded commonality of activation of core networks for abstract thought content in left anterior superior regions, and for visual-concrete thought content in right temporal-posterior inferior regions. The results suggest that two different core networks are automatedly activated when abstract or visual-concrete information, respectively, enters working memory, without a subject task or instruction about the two classes of information, and regardless of internal or external origin, and of input modality. These core machineries of working memory thus are invariant to source or modality of input when treating the two types of information.
Resumo:
Background: Visuoperceptual deficits in dementia are common and can reduce quality of life. Testing of visuoperceptual function is often confounded by impairments in other cognitive domains and motor dysfunction. We aimed to develop, pilot, and test a novel visuocognitive prototype test battery which addressed these issues, suitable for both clinical and functional imaging use. Methods: We recruited 23 participants (14 with dementia, 6 of whom had extrapyramidal motor features, and 9 age-matched controls). The novel Newcastle visual perception prototype battery (NEVIP-B-Prototype) included angle, color, face, motion and form perception tasks, and an adapted response system. It allows for individualized task difficulties. Participants were tested outside and inside the 3T functional magnetic resonance imaging (fMRI) scanner. Functional magnetic resonance imaging data were analyzed using SPM8. Results: All participants successfully completed the task inside and outside the scanner. Functional magnetic resonance imaging analysis showed activation regions corresponding well to the regional specializations of the visual association cortex. In both groups, there was significant activity in the ventral occipital-temporal region in the face and color tasks, whereas the motion task activated the V5 region. In the control group, the angle task activated the occipitoparietal cortex. Patients and controls showed similar levels of activation, except on the angle task for which occipitoparietal activation was lower in patients than controls. Conclusion: Distinct visuoperceptual functions can be tested in patients with dementia and extrapyramidal motor features when tests use individualized thresholds, adapted tasks, and specialized response systems.
Resumo:
Prediction of clinical outcome in cancer is usually achieved by histopathological evaluation of tissue samples obtained during surgical resection of the primary tumor. Traditional tumor staging (AJCC/UICC-TNM classification) summarizes data on tumor burden (T), presence of cancer cells in draining and regional lymph nodes (N) and evidence for metastases (M). However, it is now recognized that clinical outcome can significantly vary among patients within the same stage. The current classification provides limited prognostic information, and does not predict response to therapy. Recent literature has alluded to the importance of the host immune system in controlling tumor progression. Thus, evidence supports the notion to include immunological biomarkers, implemented as a tool for the prediction of prognosis and response to therapy. Accumulating data, collected from large cohorts of human cancers, has demonstrated the impact of immune-classification, which has a prognostic value that may add to the significance of the AJCC/UICC TNM-classification. It is therefore imperative to begin to incorporate the 'Immunoscore' into traditional classification, thus providing an essential prognostic and potentially predictive tool. Introduction of this parameter as a biomarker to classify cancers, as part of routine diagnostic and prognostic assessment of tumors, will facilitate clinical decision-making including rational stratification of patient treatment. Equally, the inherent complexity of quantitative immunohistochemistry, in conjunction with protocol variation across laboratories, analysis of different immune cell types, inconsistent region selection criteria, and variable ways to quantify immune infiltration, all underline the urgent requirement to reach assay harmonization. In an effort to promote the Immunoscore in routine clinical settings, an international task force was initiated. This review represents a follow-up of the announcement of this initiative, and of the J Transl Med. editorial from January 2012. Immunophenotyping of tumors may provide crucial novel prognostic information. The results of this international validation may result in the implementation of the Immunoscore as a new component for the classification of cancer, designated TNM-I (TNM-Immune).