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Biomedical subjects

Gunther Ladurner

Publications and source records attributed to Gunther Ladurner.

8 recordsLinked to original sources
PubMed2006

Evidence for a dysfunction of left posterior reading areas in German dyslexic readers.

The brain activity during a sentence reading task and a visual control task was examined with fMRI in 13 German dyslexic readers and 15 age-matched fluent readers (age: 14-16 years). These participants came from a longitudinal study and the dyslexic readers exhibited a persistent reading fluency deficit from early on. For the first time with German dyslexic readers, and in correspondence with the majority of functional imaging studies, we found reduced dyslexic activation in the left occipitotemporal cortex and in a small region of the left supramarginal gyrus. Enhanced activation was found in left inferior frontal and subcortical regions.

Adolescent↗
PubMed2005

Do visual perspective tasks need theory of mind?

Reviews [Frith, U., Frith, C.D., 2003. Development and neurophysiology of mentalising. Philos. Trans. R. Soc., B 358, 685-694.] of several imaging studies report robust involvement of medial prefrontal cortex (MPFC) in "theory of mind" (ToM) tasks. Surprisingly, this activation is notably absent when judging another person's visual perspective [Vogeley, K., May, M., Ritzl, A., Falkai, P., Zilles, K., Fink, G.R., 2004. Neural correlates of first-person perspective as one constituent of human self-consciousness. J. Cogn. Neurosci. 16, 817-827.]. The objective of our study was to see whether this activation can be recovered when the difference between what observers see is clearly one of perspectives (in front vs. behind) and not potentially a difference in what observers are looking at. Despite this change, there was still no apparent activation of MPFC. We did find activation in the temporo-parietal junction (TPJ) recently emphasized as centrally involved in processing false belief stories [Saxe, R., Kanwisher, N., 2003. People thinking about thinking people: The role of the temporo-parietal junction in "theory of mind". NeuroImage 19, 1835-1842.], which also create a stark contrast of perspectives. By integrating extant neurophysiological evidence on theory of mind processing, we suggest that the dorsal part of the TPJ region is responsible for representing perspective differences and making behavioral predictions, while the more ventral part of TPJ and the MPFC region is responsible for predicting behavioral consequences and the MPFC also emotional consequences of mental states.

Adult↗
PubMed2005

Plasma adiponectin levels and sonographic phenotypes of subclinical carotid artery atherosclerosis: data from the SAPHIR Study.

BACKGROUND AND PURPOSE: Adipose tissue produces and secretes a number of bioactive molecules, conceptualized as adipocytokines. Adiponectin has been identified as one of the adipocytokines, and hypoadiponectinemia was demonstrated in patients with obesity, diabetes mellitus, and coronary artery disease. Whether decreased adiponectin levels are cause or consequence is an important issue in the discussion on the association between adiponectin and atherosclerosis. In the present study, we investigated the association of plasma adiponectin levels with sonographic phenotypes of subclinical atherosclerosis, which may represent different stages of disease as well as common and distinct determinants. METHODS: A total of 1515 middle-aged healthy white subjects (940 males and 575 females) were included. Common carotid artery intima-media thickness (CIMT) and presence of atherosclerotic plaques were assessed by B-mode ultrasound. RESULTS: After adjustment for established risk factors, per 1 microg/mL decrease in adiponectin CIMT increased on the average by 3.48 microm in males (95% CI, 1.23 to 5.73 microm) and by 2.39 microm in females (95% CI, 0.50 to 4.27 microm). After dichotomizing adiponectin levels at the median and adjustment for established risk factors, the mean difference of CIMT between subjects with low and high adiponectin levels was 20.42 microm in men (95% CI, 6.80 to 34.04; P=0.003) and 20.75 microm in women (95% CI, 1.08 to 40.42; P=0.039). No significant relationship was found between adiponectin levels and presence of atherosclerotic plaques. CONCLUSIONS: Our results demonstrate an independent negative association of adiponectin levels and CIMT, whereas no relationship with presence of atherosclerotic plaques was found, thus suggesting hypoadiponectinemia as a risk factor in the development of early atherosclerosis.

Adiponectin↗
PubMed2005

The metabolic syndrome is a stronger risk factor for early carotid atherosclerosis in women than in men.

BACKGROUND AND PURPOSE: The metabolic syndrome (MetS) is associated with an increased risk for subsequent development of type 2 diabetes mellitus, cardiovascular disease, and stroke. Type 2 diabetes increases the risk of stroke and coronary heart disease in women to a greater extent than in men, and thus the question arises whether there are sex differences in the association of early atherosclerosis and MetS. METHODS: 1588 middle-aged Austrian subjects (1001 males, 587 females) were included in the present study. MetS was defined by the criteria of the National Cholesterol Education Program Adult Treatment Panel III. Early atherosclerosis was assessed by intima-media thickness (IMT) and extent of plaques (B-score) of the carotid arteries. RESULTS: B-score and carotid artery IMT parameters were significantly higher in subjects with the MetS. After adjustment for established risk factors, the difference in B-score remained significant only in women. Computed common carotid artery IMT values using general linear model equations with age, body mass index, and low-density lipoprotein cholesterol as covariates displayed the highest values for men with MetS (811.8+/-9.5 microm). Women with MetS (797.6+/-15 microm) and men without the syndrome (788.8+/-5 microm) showed similar IMTs, whereas women without the MetS presented significantly lower values (735.6+/-7 microm). Among the subcomponents of the MetS, high-density lipoprotein cholesterol showed the strongest impact on IMT in men, whereas blood glucose ranked first in women. CONCLUSIONS: The effect of MetS on early atherosclerosis is more pronounced in females. The impact of the components of MetS on carotid IMT differs between men and women.

Adult↗
PubMed2005

Magnetic resonance spectroscopy of memory and frontal brain region in early multiple sclerosis.

In vivo proton magnetic resonance spectroscopy (1H-MRS) has been used to assess biochemical changes that occur in demyelinating lesions and in normal appearing white matter (NAWM) in multiple sclerosis (MS) patients. N-acetylaspartate (NAA) levels in MS patients may indicate neural viability. In early stages of MS, patients may suffer from slight cognitive impairment. The objective of this study was to investigate memory function in relation to biochemical properties of frontal brain areas of MS patients. Twenty-one patients with relapsing-remitting MS and 21 healthy comparison subjects were examined psychometrically using the Wechsler Memory Scale (WMS) and the Multiple Sclerosis Functional Composite (MSFC) scale, and (1H-MRS) was used to examine frontal deep white matter (left hemisphere) and the frontal cingulate gyrus (Brodmann areas 24/32, bihemispheric). A significant reduction of the NAA/Creatine (Cr) ratio in the frontal cingulate gyrus among the MS patient group was detected when compared to healthy subjects. A significant decrease in the NAA/Cr ratio was also found in volumes of cerebral deep white matter, including plaques, in the MS patients. No NAA/Cr ratio changes were found in NAWM. Differences in MSFC results did not reach statistical significance, but the WMS general memory score showed a significant statistical difference between the patient group and healthy subjects. Regression analysis showed the gray matter NAA/Cr ratio of the frontal cingulate gyrus to be significantly related to distinct memory functions. The authors conclude that (1H-MRS) of gray matter in early stages of MS may be pertinent in the detections of early metabolic disturbances, particularly in subjects with or without minor neurological impairment. Findings suggest a general relationship between the metabolic status of the frontal cortices and memory function.

Adolescent↗
PubMed2004

Stimulating music increases motor coordination in patients afflicted with Morbus Parkinson.

The present study measured the short-term effect of special stimulating music on motor coordination in Parkinson patients. Eleven patients with a dominant akinetic Parkinson syndrome as well as ten healthy persons (age-matched control group) participated in this study. In the Parkinson group, the measurement of fine motor coordination with the 'Vienna Test System' showed an improvement in two (aiming, line tracking) of the four subtests after listening to the music. The patients improved their performance with the right arm significantly in the subtest aiming-error-time. No statistical differences were found in the other two subtests (steadiness, tapping) in both groups. There was also no improvement in frequency of tapping movement on the power-force-working-plate. Accordingly, music effects more the precision of a movement than the speediness. The measurements on the power-force-working-plate showed a significant improvement in two of five measured parameters: contact time, variability coefficient for total step and impact maximum changed significantly. This study gives evidence that specific music can improve the precision of arm and finger movements.

Acoustic Stimulation↗
PubMed2004

The visual word form area and the frequency with which words are encountered: evidence from a parametric fMRI study.

Cohen and Dehaene et al. proposed that the Visual Word Form Area (VWFA) in the left midfusiform gyrus, contrary to its name, is limited to the extraction of an abstract letter string and not involved in proper visual word recognition. We examined this prelexical function of the VWFA by a parametric block design with five levels of written word frequency. The lowest level was represented by pseudowords and the highest level by words of very high frequency. Contrary to the assumed prelexical function of the VWFA, increasing frequency was associated with decreasing brain activation in a large posterior cluster of the left hemisphere including middle and posterior fusiform regions. The same negative relation between frequency and activation was found in several left frontal clusters. The relation of increasing frequency and decreasing activation in occipitotemporal regions corresponds to a similar relation in the same brain regions found by studies which experimentally manipulated object or face familiarity. This convergence suggests that fusiform regions are specialized for extracting and storing abstract patterns when processing visual objects and these patterns serve as recognition units in subsequent encounters with the same objects.

Adolescent↗