Biomedical subjects

Andreas Löw

Publications and source records attributed to Andreas Löw.

5 recordsLinked to original sources

PubMed2006

Disordered semantic representation in schizophrenic temporal cortex revealed by neuromagnetic response patterns.

BACKGROUND: Loosening of associations and thought disruption are key features of schizophrenic psychopathology. Alterations in neural networks underlying this basic abnormality have not yet been sufficiently identified. Previously, we demonstrated that spatio-temporal clustering of magnetic brain responses to pictorial stimuli map categorical representations in temporal cortex. This result has opened the possibility to quantify associative strength within and across semantic categories in schizophrenic patients. We hypothesized that in contrast to controls, schizophrenic patients exhibit disordered representations of semantic categories. METHODS: The spatio-temporal clusters of brain magnetic activities elicited by object pictures related to super-ordinate (flowers, animals, furniture, clothes) and base-level (e.g. tulip, rose, orchid, sunflower) categories were analysed in the source space for the time epochs 170-210 and 210-450 ms following stimulus onset and were compared between 10 schizophrenic patients and 10 control subjects. RESULTS: Spatio-temporal correlations of responses elicited by base-level concepts and the difference of within vs. across super-ordinate categories were distinctly lower in patients than in controls. Additionally, in contrast to the well-defined categorical representation in control subjects, unsupervised clustering indicated poorly defined representation of semantic categories in patients. Within the patient group, distinctiveness of categorical representation in the temporal cortex was positively related to negative symptoms and tended to be inversely related to positive symptoms. CONCLUSION: Schizophrenic patients show a less organized representation of semantic categories in clusters of magnetic brain responses than healthy adults. This atypical neural network architecture may be a correlate of loosening of associations, promoting positive symptoms.

Adult↗

PubMed2006

Rapid picture presentation and affective engagement.

Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.

Adult↗

PubMed2003

Semantic categorization in the human brain: spatiotemporal dynamics revealed by magnetoencephalography.

We examined the cortical representation of semantic categorization using magnetic source imaging in a task that revealed both dissociations among superordinate categories and associations among different base-level concepts within these categories. Around 200 ms after stimulus onset, the spatiotemporal correlation of brain activity elicited by base-level concepts was greater within than across superordinate categories in the right temporal lobe. Unsupervised clustering of data showed similar categorization between 210 and 450 ms mainly in the left hemisphere. This pattern suggests that well-defined semantic categories are represented in spatially distinct, macroscopically separable neural networks, independent of physical stimulus properties. In contrast, a broader, task-required categorization (natural/man-made) was not evident in our data. The perceptual dynamics of the categorization process is initially evident in the extrastriate areas of the right hemisphere; this activation is followed by higher-level activity along the ventral processing stream, implicating primarily the left temporal lobe.

Adult↗

PubMed2003

[Curriculum for "structured medical care"].

In 2001, the Advisory Council for the Concerted Action in Health Care reported deficits of medical care in Germany and disclosed a potential for improvement in the quality and efficiency of care. The introduction and implementation of disease management programs counteracts these deficits by standardising medical care processes for defined patient groups in co-operation with participants from different sectors and professions. Thus, doctors are well advised to learn as much as possible about DMPs for two reasons: they both create and offer DMPs! And this gave rise to an initiative of the German Medical Association and the National Association of Statutory Health Insurance Physicians to create an advanced modularly constructed training program especially for doctors, which was first published on January 24th, 2003.

Curriculum↗

PubMed2002

[The National Program for disease management--guidelines under the auspices of the German Medical Association--a method report].

In March 2002, the German Medical Association established a National Programme for Disease Management Guidelines (DMG). This programme focuses on the development and implementation of consented key recommendations of German guidelines and evidence-based treatment recommendations for specific prioritized problems of health care issued by various organisations. Among other things, the aim is to ensure (1) that guidelines within a framework of structured care should not assume the character of directives; (2) that the evidence-based principles for structured care programmes be both scientifically accounted for and practicable and consider guidelines that have already proved to work; (3) that a consensus be obtained between the institutions of the medical self-governing bodies, the Association of the Scientific Medical Societies in Germany (AWMF) and the relevant medical societies concerning the identification, updating and implementation of the key topics of structured care programmes: (4) that the outcomes of the German Guideline Clearinghouse be taken into consideration. The methodological foundations of this programme for disease management guidelines are outlined in the following method report.

Germany↗