The role of delta and theta oscillations during ego-motion in healthy adult volunteers.

The successful cortical processing of multisensory input typically requires the integration of data represented in different reference systems to perform many fundamental tasks, such as bipedal locomotion. Animal studies have provided insights into the integration processes performed by the neocortex and have identified region specific tuning curves for different reference frames during ego-motion. Yet, there remains almost no data on this topic in humans.In this study, an experiment originally performed in animal research with the aim to identify brain regions modulated by the position of the head and eyes relative to a translational ego-motion was adapted for humans. Subjects sitting on a motion platform were accelerated along a translational pathway with either eyes and head aligned or a 20° yaw-plane offset relative to the motion direction while EEG was recorded.Using a distributed source localization approach, it was found that activity in area PFm, a part of Brodmann area 40, was modulated by the congruency of translational motion direction, eye, and head position. In addition, an asymmetry between the hemispheres in the opercular-insular region was observed during the cortical processing of the vestibular input. A frequency specific analysis revealed that low-frequency oscillations in the delta- and theta-band are modulated by vestibular stimulation. Source-localization estimated that the observed low-frequency oscillations are generated by vestibular core-regions, such as the parieto-opercular region and frontal areas like the mid-orbital gyrus and the medial frontal gyrus.

Spectral fingerprints of correct vestibular discrimination of the intensity of body accelerations.

Perceptual decision-making is a complex task that requires multiple processing steps performed by spatially distinct brain regions interacting in order to optimize perception and motor response. Most of our knowledge on these processes and interactions were derived from unimodal stimulations of the visual system which identified the lateral intraparietal area and the posterior parietal cortex as critical regions. Unlike the visual system, the vestibular system has no primary cortical areas and it is associated with separate multisensory areas within the temporo-parietal cortex with the parieto-insular vestibular cortex, PIVC, being the core region. The aim of the presented experiment was to investigate the transition from sensation to perception and to reveal the main structures of the cortical vestibular system involved in perceptual decision-making. Therefore, an EEG analysis was performed in 35 healthy subjects during linear whole-body accelerations of different intensities on a motor-driven motion platform (hexapod). We used a discrimination task in order to judge the intensity of the accelerations. Furthermore, we manipulated the expectation of the upcoming stimulus by indicating the probability (25%, 50%, 75%, 100%) of the motion direction. The analysis of the vestibular evoked potentials (VestEPs) showed that the decision-making process leads to a second positive peak (P2b) which was not observed in previous task-free experiments. The comparison of the estimated neural generators of the P2a and P2b components showed significant activity differences in the anterior cingulus, the parahippocampal and the middle temporal gyri. Taking into account the time courses of the P2 components, the physical properties of the stimuli, and the responses given by the subjects we conclude that the P2b likely reflects the transition from the processing of sensory information to perceptual evaluation. Analyzing the decision-uncertainty reported by the subjects, a persistent divergence of the time courses starting at 188 â€‹ms after the acceleration was found at electrode Pz. This finding demonstrated that meta-cognition by means of confidence estimation starts in parallel with the decision-making process itself. Further analyses in the time-frequency domain revealed that a correct classification of acceleration intensities correlated with an inter-trial phase clustering at electrode Cz and an inter-site phase clustering of theta oscillations over frontal, central, and parietal cortical areas. The sites where the phase clustering was observed corresponded to core decision-making brain areas known from neuroimaging studies in the visual domain.

Distorted mental spatial representation of multi-level buildings - Humans are biased towards equilateral shapes of height and width.

A distorted model of a familiar multi-level building with a systematic overestimation of the height was demonstrated earlier in psychophysical and real world navigational tasks. In the current study we further investigated this phenomenon with a tablet-based application. Participants were asked to adjust height and width of the presented buildings to best match their memory of the dimensional ratio. The estimation errors between adjusted and true height-width ratios were analyzed. Additionally, familiarity with respect to in- and outside of the building as well as demographic data were acquired. A total of 142 subjects aged 21 to 90 years from the cities of Bern and Munich were tested. Major results were: (1) a median overestimation of the height of the multi-level buildings of 11%; (2) estimation errors were significantly less if the particular building was unknown to participants; (3) in contrast, the height of tower-like buildings was underestimated; (4) the height of long, flat shaped buildings was overestimated. (5) Further features, such as the architectonical complexity were critical. Overall, our internal models of large multi-level buildings are distorted due to multiple factors including geometric features and memory effects demonstrating that such individual models are not rigid but plastic with consequences for spatial orientation and navigation.

Rey-Osterrieth Complex Figure - copy and immediate recall (3 minutes): Normative data for Spanish-speaking pediatric populations.

OBJECTIVE: To generate normative data for the Rey-Osterrieth Complex Figure (ROCF) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the ROCF as part of a larger neuropsychological battery. The ROCF copy and immediate recall (3 minutes) scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effect for age on copy and immediate recall scores, such that scores increased linearly as a function of age. Age2 affected ROCF copy score for all countries, except Puerto Rico; and ROCF immediate recall scores for all countries, except Chile, Guatemala, Honduras, Paraguay, and Puerto Rico. Models indicated that children whose parent(s) had a MLPE >12 years obtained higher scores compared to children whose parent(s) had a MLPE≤12 years for Chile, Puerto Rico, and Spain in the ROCF copy, and Paraguay and Spain for the ROCF immediate recall. Sex affected ROCF copy and immediate recall score for Chile and Puerto Rico with girls scoring higher than boys. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate approach to interpret the ROCF Test in pediatric populations.

The cortical spatiotemporal correlate of otolith stimulation: Vestibular evoked potentials by body translations.

The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1. to estimate the sources of the vestibular evoked potentials (VestEPs) by means of distributed source localization (n=49), and 2. to reveal modulations of the VestEPs through the underlying acceleration intensity (n=24). For both experiments subjects were accelerated along the main axis (left/right, up/down, fore/aft) while the EEG was recorded. We were able to identify five VestEPs (P1, N1, P2, N2, P3) with latencies between 38 and 461 ms as well as an evoked beta-band response peaking with a latency of 68 ms in all subjects and for all acceleration directions. Source localization gave the cingulate sulcus visual (CSv) area and the opercular-insular region as the main origin of the evoked potentials. No lateralization effects due to handedness could be observed. In the second experiment, area CSv was shown to be integral in the processing of acceleration intensities as sensed by the otolith organs, hinting at its potential role in ego-motion detection. These robust VestEPs could be used to investigate the mechanisms of inter-regional interaction in the natural context of vestibular processing and multisensory integration.

Evidence for photosensitised hydrogen production from water in the absence of precious metals, redox-mediators and co-catalysts.

The water-soluble zinc porphyrin complex Zn(TPPS)4- with TPPS = tetrakis-(4-sulfonatophenyl)porphyrin surprisingly was found to produce significant amounts of hydrogen from aqueous sulfite or amine solutions under visible-light exposure without requiring any other components such as electron relays or additional proton reduction catalysts. Although the production rates and total amounts of chemically stored fuel obtained under these conditions are still much too low to be relevant for practical applications, the background of this unprecedented observation was further studied in its own right. Since the central metal zinc is unlikely to be involved in proton-coupled electron transfer steps upon long-wavelength irradiation and the process does not seem to be much affected by variations of the electron donor added, the mechanism of photocatalytic H2 release is suggested to involve previously neglected redox features of the in situ generated hydroporphyrin ligand system in aqueous solution.

Measuring changes in the optic nerve sheath diameter in patients with idiopathic normal-pressure hydrocephalus: a useful diagnostic supplement to spinal tap tests.

BACKGROUND AND PURPOSE: Cerebrospinal fluid (CSF) removal improves clinical symptoms of many patients with idiopathic normal-pressure hydrocephalus (iNPH). The aim of this study was to investigate the correlation of changes in the optic nerve sheath diameter (ONSD) with patient responses to CSF removal. METHODS: Transorbital ultrasonography was performed to obtain ONSD measurements in 31 patients with iNPH before and after lumbar puncture. Measurements were obtained while patients were supine and upright. Changes in the ONSD between supine and upright positions [ONSD variability (ONSD-V)] were assessed and compared with those in 60 healthy volunteers. ONSD-V was correlated with relative changes in a validated iNPH severity (Boon) score. RESULTS: Mean pre-puncture ONSD-V was significantly lower in healthy volunteers and patients with no response to CSF removal (Fisher test) [0.05 ± 0.14 mm (SD)] than in responsive patients [0.37 ± 0.20 mm (SD), P < 0.001]. ONSD-V predicted response to the spinal tap test (odds ratio, 0.30; 95% confidence interval, 0.12-0.75 mm, P = 0.011). The higher the ONSD-V, the better the therapeutic effect (χ2 = 14.980, P < 0.001). The post-spinal tap test ONSD-V correlated significantly with clinical severity in the motor portion of the Boon score [0.16 ± 0.23 mm (SD), P = 0.003]. CONCLUSIONS: The ONSD-V before and after spinal tap test correlated well with the clinical effects of CSF removal. Transorbital ultrasonography seems to be a reliable, safe add-on to the Fisher test and may support selection of patients for shunt intervention.

Antimony porphyrins as red-light powered photocatalysts for solar fuel production from halide solutions in the presence of air.

Halide ions (X(-)) as cheap and abundant electron donors are oxidized with simulated sunlight in a photocatalytic reaction based on robust antimony porphyrins acting as red-light harvesting multielectron transfer sensitizers. Besides halogen formation (X2/X3(-)) this solar energy storing process under certain conditions also accumulates hydrogen peroxide (H2O2) as a second energy-rich compound.

Appraisal of the signal-to-noise-ratio of uni- and bipolar recordings of ocular vestibular evoked myogenic potentials.

Ocular vestibular evoked myogenic potentials (oVEMPs) are a non-invasive method to investigate otolith function mediated via the superior vestibular nerve. However, the herein used recordings and protocols may alter within different studies. In particular the diverging use of electrode configuration regarding polarity or even electrode position varies across studies. Therefore, a systematic analysis and appraisal of the different electrode configuration seems mandatory. In this study we compared the quality of uni- and bipolar recordings based on the signal to noise ratio (SNR). We recoded oVEMPs using a uni- and bipolar electrode configuration simultaneously and compared the recorded amplitudes and latencies and calculated the SNR. The amplitudes recorded by the unipolar configurations were significantly (p < 0.01) increased compared to the bipolar configuration. However, the SNR of the bipolar setup was significantly better (p < 0.05) when compared to the unipolar setup. Additionally, we estimated a transfer function that enabled a comparison of uni- and bipolar recordings. To conclude, the variety of setups used for oVEMP recording hinder a comparison of results and unipolar electrode configurations have clear disadvantages.

Ocular color-coded sonography - a promising tool for neurologists and intensive care physicians.

Ocular color-coded duplex sonography (OCCS), when performed within the safety limits of diagnostic ultrasonography, is an easy noninvasive technique with high potential for diagnosis and therapy in diseases with raised intracranial pressure and vascular diseases affecting the eye. Despite the capabilities of modern ultrasound systems and its scientific validation, OCCS has not gained widespread use in neurological practice. In this review, the authors describe the technique and main parameter settings of OCCS systems to reduce potential risks as thermal or cavitational effects for sensitive orbital structures. Applications of OCCS are the determination of intracranial pressure in emergency medicine, and follow-up evaluations of idiopathic intracranial hypertension and ventricular shunting by measuring the optic nerve sheath diameter. A diameter of 5.7 - 6.0 mm corresponds well with symptomatically increased intracranial pressure (> 20 cmH2O). OCCS also helps to discriminate between different etiologies of central retinal artery occlusion - by visualization of a "spot sign" and Doppler flow analysis of the central retinal artery - and aids the differential diagnosis of papilledema. At the end perspectives are illustrated that combine established ultrasound methods such as transcranial color-coded sonography with OCCS.

The retrobulbar "spot sign" as a discriminator between vasculitic and thrombo-embolic affections of the retinal blood supply.

PURPOSE: Sudden retinal blindness is a common complication of temporal arteritis (TA). Another common cause is embolic occlusion of the central retinal artery (CRA). The aim of this prospective study was to examine the diagnostic value of hyperechoic material in the CRA for the exclusion of vasculitis as a cause. The authors used orbital color-coded sonography (OCCS) for the detection of hyperechoic material. MATERIALS AND METHODS: 24 patients with sudden vision loss were included in the study after the exclusion of other causes (e. g. vitreous bleeding, retinal detachment). Parallel to routine diagnostic workup, OCCS was performed in all patients. RESULTS: 7 patients with a diagnosis of TA presented with different degrees of hypoperfusion in the CRA without hyperechoic material (referred to as "spot sign") detected by OCCS. Diagnostic workup in the remaining 17 patients revealed other causes of sudden vision loss, such as central retinal artery occlusion (CRAO) (12), anterior ischemic optic neuropathy (AION) (2), upstream vascular stenosis or occlusion (2) and delayed reperfusion of the CRA (1). The hyperechoic "spot sign" was visible in 10 of 12 patients (83 %) with embolic CRAO. The detection of embolic CRAO using the "spot sign" had a sensitivity of 83 % and a specificity of 100 %. The missing "spot sign" in patients with TA was a highly specific finding (p-value 0.01). CONCLUSION: The detection of the "spot sign" specifically minimizes the probability of TA as a reason for sudden blindness.

Age effects on the P300 potential and the corresponding fMRI BOLD-signal.

Age has been reported to influence amplitude and latency of the P300 potential. Nevertheless, it is not yet fully understood which brain regions are responsible for these effects. The aim of this study was to investigate age-effects on the P300 potential and the simultaneously acquired BOLD signal of functional MRI. 32 healthy male subjects were investigated using an auditory oddball paradigm. The functional MRI data were acquired in temporal synchrony to the task. The evoked potential data were recorded during the intervals in between MR image acquisitions in order to reduce the influence of the scanner noise on the presentation of the tones and to reduce gradient artifacts. The age-effects were calculated by means of regression analyses. In addition, brain regions modulated by the task-induced amplitude variation of the P300 were identified (single trial analysis). The results indicated an age effect on the P300 amplitude. Younger subjects demonstrated increased parietal P300 amplitudes and increased BOLD responses in a network of brain regions including the anterior and posterior cingulate cortex, the insula, the temporo-parietal junction, the superior temporal gyrus, the caudate body, the amygdala and the parahippocampal gyrus. Single trial coupling of EEG and fMRI indicated that P300 amplitudes were predominantly associated with neural responses in the anterior cingulate cortex, the putamen and temporal brain areas. Taken together, the results indicate diminished neural responses in older compared to younger subjects especially in frontal, temporo-parietal and subcortical brain regions.

Removal of prion infectivity by affinity ligand chromatography during OctaplasLG® manufacturing--results from animal bioassay studies.

BACKGROUND: OctaplasLG(®) is a 2nd-generation virus inactivated pooled plasma for infusion. Prions are removed by the principle of chromatography, utilizing an affinity ligand gel (LG) developed for binding of prion proteins and their infectivity. The goal of this study was to verify, using the gold standard animal bioassay system, whether or not prion infectivity can be removed by the LG affinity step under conditions used in the routine manufacturing process. MATERIALS AND METHODS: Aliquots of pooled plasma were spiked with a microsomal/cytosolic (MIC) fraction of brain-derived hamster-adapted scrapie 263K and subjected to the OctaplasLG(®) manufacturing process. Validated Western blot tests and animal bioassays studies were performed to determine the logarithmic reduction factors (RF) and the prion infectivity binding capacity. RESULTS: Bioassay studies demonstrated different logarithmic RFs (i.e. 1·73 and 0·76 log(10)) at two different plasma-to-resin ratios, the latter one representing the actual manufacturing ratio of 100:1, which can be explained by the differences in the study design. However, both bioassay studies showed a reproducible and high prion infectivity binding capacity of ≥5·64 log(10) ID(50)/ml gel. CONCLUSION: Bioassay studies confirmed the capacity of the LG to bind brain-derived MIC prion proteins spiked into plasma. Even through infectivity was still detected following passage over the LG, this can be attributed to the high loads used in the study design, and the binding capacity of the LG still ensures a significant safety margin--binding the prion agents at the levels of prion infectivity that might be present in plasma and beyond.

Uncompromised quality of the cement mantle in Exeter femoral components implanted through a minimally-invasive direct anterior approach. A prospective, randomised cadaver study.

A complete cement mantle is important for the longevity of a total hip replacement. In the minimally-invasive direct anterior approach used at the Innsbruck University hospital, the femoral component has to be inserted into the femoral canal by an angulated movement. In a cadaver study, the quality and the extent of the cement mantle surrounding 13 Exeter femoral components implanted straight through a standard anterolateral transgluteal approach were compared with those of 13 similar femoral components implanted in an angulated fashion through a direct anterior approach. A third-generation cementing technique was used. The inner and outer contours of the cement mantles was traced from CT scans and the thickness and cross-sectional area determined. In no case was the cement mantle incomplete. The total mean thickness of the cement mantle was 3.62 mm (95% confidence interval 3.59 to 3.65). The mean thickness in the group using the minimally-invasive approach was 0.16 mm less than that in the anterolateral group. The distribution of the thickness was similar in the two groups. The mean thickness was less on the anteromedial and anterolateral aspect than on the posterior aspect of the femur. There is no evidence that the angulated introduction of Exeter femoral components in the direct anterior approach in cadavers compromises the quality, extent or thickness of the cement mantle.

Opioid addicts at admission vs. slow-release oral morphine, methadone, and sublingual buprenorphine maintenance treatment participants.

With use of a randomized study design, quality of life (QOL) and physical symptoms of opioid addicts at admission were compared with slow-release oral morphine, methadone, and sublingual buprenorphine maintenance program participants after 6 months of treatment. The study was conducted from February to July 2004 in the outpatient drug user treatment center at University Department of Psychiatry at Innsbruck, providing maintenance treatment programs and detoxification in Tyrol, Austria. One hundred twenty opioid users seeking treatment were compared with 120 opioid-dependent patients retained for 6 months on a slow-release oral morphine, methadone, or sublingual buprenorphine maintenance program. The German version ("Berlin Quality of Life Profile") of the Lancashire Quality of Life Profile was used, and illicit opioid use was determined by urinalysis. Physical symptoms were measured by using the Opioid Withdrawal Scale. Urinalyses revealed a significantly lower consumption of cocaine and opioids in all three substitution groups than in patients at admission (p < 0.001 and p < or = 0.004, respectively). Both the buprenorphine and the methadone maintenance group showed significantly more favorable values than opioid clients at admission for stomach cramps (p < or = 0.002), muscular tension (p < or = 0.027), general pain (p < or = 0.001), feelings of coldness (p < or = 0.000), heart pounding (p < or = 0.008), runny eyes (p < or = 0.047), and aggressions (p < or = 0.009). Patients who received slow-release oral morphine treatment generally showed the least favorable QOL scores compared with patients at admission or sublingual buprenorphine and methadone clients. Patients in the sublingual buprenorphine or methadone program showed nearly the same QOL scores. The buprenorphine and the methadone maintenance group showed significantly more favorable values than opioid clients at admission regarding leisure time (p < or = 0.019), finances (p < or = 0.014), mental health (p < or = 0.010), and overall satisfaction (p < or = 0.010). Slow-release oral morphine is a well-established treatment for pain, but more research is required to evaluate it as a treatment for heroin dependence. The present data indicate that slow-release oral morphine could have some disadvantages compared with sublingual buprenorphine and methadone in QOL, physical symptoms, and additional consumption. The results further suggest that buprenorphine treatment is as effective as methadone in effects on quality of life and physical symptoms.

Gender differences in health-related quality of life on admission to a maintenance treatment program.

We compared the gender differences in health-related quality of life (QOL) on admission to a maintenance program. 103 opioid users (65 men and 38 women) admitted to a maintenance treatment program during 2000-2002 were studied. During this period we assessed the QOL status using the German version ('Berlin Quality of Life Profile') of the Lancashire Quality of Life Profile. Physical symptoms were measured using the Opioid Withdrawal Scale. 312 urine screening tests were carried out to evaluate consumption. The female group showed significantly less additional consumption of other opiates (p = 0.043) compared with the male group. The male group showed significantly better QOL scores in self-esteem (p = 0.015), psychical health (p = 0.027), and law and security (p = 0.008). The outcome measures for withdrawal scores showed significantly less symptoms for males in twitching of muscles (p = 0.034), vomiting (p = 0.002), depressions (p = 0.004) and poor appetite (p = 0.008). In summary, both genders showed only a few significant differences on admission in terms of QOL and physical symptoms. The predominant effects of drug use appear to eclipse the gender-related role pattern. Further exploration of gender and QOL could have important theoretical and treatment implications.