Level of uncertainty about the affective nature of a pictorial stimulus influences anticipatory neural processes: An event-related potential (ERP) study.

Uncertainty about the emotional impact of future events is a common part of everyday life. However, relatively little is known about whether the level of uncertainty about the affective nature of an upcoming visual image influences anticipatory neurocognitive processes. To investigate this, participants viewed a series of negative and neutral pictures, which were preceded by abstract anticipatory cues. Neural activity was measured using event-related potentials (ERPs). In the 'uncertain' cue condition, the cue could be followed by either a negative or a neutral picture with equal probability; in the 'fairly uncertain' condition the cue was followed by a negative picture on 70% of trials, and by a neutral picture on 30% of trials. In the 'certain' condition, the cue was always followed by a negative picture. For the P200 component, reflecting early stages of selective attention, there was no amplitude difference between cue conditions. At later stages of processing, the early posterior negativity (EPN) amplitude was enhanced for cues indicating a greater level of certainty, and the late positive potential (LPP) amplitude was greater for certain, compared to fairly uncertain and uncertain cues. The stimulus preceding negativity (SPN), an index of anticipatory processing, was more negative for certain cues compared to fairly uncertain and uncertain cues. For the SPN there was no difference between fairly uncertain and uncertain cues. These results provide evidence that the level of uncertainty regarding the affective nature of an upcoming picture influenced several stages of processing during the anticipation of the stimulus.

[Frequency and risk factors associated with post-stroke dementia-an observational study on stroke patients without premorbid cognitive impairment]. / Häufigkeit und Risikofaktoren der Post-Stroke-Demenz ­ eine Beobachtungsstudie zu Schlaganfallpatienten ohne vorbestehende kognitive Defizite.

BACKGROUND: Longitudinal studies on cognitive outcomes after stroke revealed heterogeneous results and the underlying pathology and risk factors for so-called post-stroke dementia are unclear. OBJECTIVE: To assess long-term cognitive performance changes in patients after the first ischemic stroke and to evaluate possible risk factors for post-stroke dementia. MATERIAL AND METHODS: In this study 66 clinically mildly affected patients aged 54-87 years without a history of dementia underwent extensive neuropsychological assessment after first ever ischemic stroke and again 6 months after the event (follow-up assessment). Demographic, clinical and paraclinical parameters were assessed as potential predictors for long-term cognitive outcome. RESULTS: At the group level significant performance improvements were found for most of the neurocognitive domains at the follow-up assessment. The greatest cognitive improvement was found in visuospatial processing. Immediately after stroke 54.5% of patients were considered cognitively impaired (z-scores < -2 in at least 2 neurocognitive domains). At follow-up only 16.7% were considered cognitively impaired according to this criterion and among these only 2 patients (3%) had developed a new, clinically relevant cognitive impairment (i.e. post-stroke dementia). Patients with inferior cognitive performance improvements at follow-up had on average larger brain lesions caused by the stroke as well as a prediabetic metabolic status. DISCUSSION: The probability of developing a post-stroke dementia syndrome is lower than previously assumed in patients with first ever stroke, with only mild clinical disability and without premorbid cognitive impairment. Long-term cognitive impairment could primarily be determined by the size of the lesioned brain area as well as the premorbid (pre)diabetic status.

Early effective treatment may protect from cognitive decline in paediatric multiple sclerosis.

BACKGROUND: Cognitive impairment (CI) is a critical feature for patients with childhood or juvenile multiple sclerosis (MS). OBJECTIVE: To promote the understanding of CI and to address the impact of different pharmacological treatment strategies on cognitive performance in this patient group. METHODS: A cohort of 19 patients with therapy-naïve or ß-Interferon-treated juvenile MS completed a comprehensive neuropsychological assessment at initial presentation (baseline) and on average 2.5 years later (follow-up). The assessments were complemented with a neuropaediatric examination and conventional cerebral magnetic resonance imaging (MRI). RESULTS: 9 patients (47%) were impaired in at least one test at baseline (z-score <-1.645 compared with age-adjusted normative data), with the highest impairment frequency in the domains processing speed and attention & executive functions. At follow-up a higher impairment frequency was prominent in those patients whose therapy had not been escalated (N = 13, 69% impaired in at least one test), while cognition was preserved or ameliorated in patients whose treatment had been escalated to highly effective drugs (N = 6, 0% impaired) during the observational period. These group differences at follow-up were not attributable to differences regarding demographics, MRI metrics or cognitive performance at baseline. CONCLUSION: Our findings confirm that paediatric MS is associated with considerable CI already in early disease stages. Early administration of highly effective treatment may protect from cognitive decline or alleviate CI in juvenile MS, but larger controlled trials are warranted to confirm these preliminary results.

[Implementation of the German S3 guidelines on dementia in clinical practice: wish or reality?] / Umsetzung der S3-Leitlinie "Demenzen" im klinischen Alltag: Wunsch oder Wirklichkeit?

BACKGROUND: Published in 2009, the German S3 guidelines on dementia define a milestone in quality improvement of the diagnostics and treatment of dementia. In clinical practice patients suffering from dementia are primarily treated by physicians in private practice; therefore, this study examined how the guidelines are implemented in outpatient clinical settings. Furthermore, it aimed at the identification of behavioral determinants that govern the actual diagnostic and therapeutic approach in clinical practice. METHODS: Physicians involved in the primary care of dementia patients were asked to participate in a nationwide internet survey. The questionnaire covered aspects on the diagnostic and therapeutic care of dementia patients as recommended by the S3 guidelines. Behavioral determinants of the implementation of the guidelines (e. g. treatment decisions) were derived from an established psychological prediction model. RESULTS: Out of a total of 2755 physicians contacted, the data of 225 participants could be used in this study. The diagnostic recommendations of the S3 guidelines were implemented in satisfactory measures (e.g. combined cognitive screening in at least 68%, cerebral neuroimaging in at least 93% and specific laboratory diagnostics in at least 27% of cases); however, only two thirds of the patients with indications for a guideline-conform therapy were treated in accordance with the S3 guidelines. There was a substantial prescription of non-recommended drugs and a notable long-term use of antipsychotic drugs (prescription by at least 14% of non-neurological medical specialists and by 8% of neurologists and psychiatrists). When considering the behavioral determinants in the implementation of the guidelines, normative assumptions ("my colleagues and patients expect me to comply with the guidelines") surprisingly had the highest impact, which was then followed by attitudes towards the behavior ("utilization of the guidelines improves diagnostics and therapy"). CONCLUSION: The German S3 guidelines on dementia were satisfactorily implemented in outpatient clinical practice; however, deficits existed in the frequency of the pharmaceutical treatment of patients with indications for therapy, the prescription of non-recommended drugs and the relatively common use of permanent neuroleptic medications. Interestingly, the motivation for implementation of the guidelines was not primarily influenced by the physicians' personal convictions but mainly stimulated by the expectations of others.

Spatial attention modulates sound localization in barn owls.

Attentional influence on sound-localization behavior of barn owls was investigated in a cross-modal spatial cuing paradigm. After being cued to the most probable target side with a visual cuing stimulus, owls localized upcoming auditory target stimuli with a head turn toward the position of the sound source. In 80% of the trials, cuing stimuli pointed toward the side of the upcoming target stimulus (valid configuration), and in 20% they pointed toward the opposite side (invalid configuration). We found that owls initiated the head turns by a mean of 37.4 ms earlier in valid trials, i.e., mean response latencies of head turns were reduced by 16% after a valid cuing stimulus. Thus auditory stimuli appearing at the cued side were processed faster than stimuli appearing at the uncued side, indicating the influence of a spatial-selective attention mechanism. Turning angles were not different when owls turned their head toward a cued or an uncued location. Other types of attention influencing sound localization, e.g., a reduction of response latency as a function of the duration of cue-target delay, could not be observed. This study is the first attempt to investigate attentional influences on sound localization in an animal model.

Coding for auditory space in the superior colliculus of the rat.

Although the rat is often used to determine behavioural sound-localization capabilities or neuronal computation of binaural information, the representation of auditory space in the rat brain has not been investigated so far. We obtained extracellular recordings from auditory neurons in the superior colliculus of anaesthetized rats and examined them for spatial tuning characteristics and topographical order. Many neurons (73%) showed significant tuning, with a single peak in the azimuth response profiles based on spike rates and response latencies. Best azimuth values from neurons in one SC were generally tuned to contralateral and rarely to frontal or ipsilateral directions. Tuning width was mostly broad; at supra-threshold sound pressure levels (35 dB SPL), 55% of the units had a tuning width of > 120 degrees in contralateral space. Additionally, tuning width increased with stimulation intensity. A significant but considerably scattered topographical order of best azimuth directions was observed in the deep layers of the superior colliculus with frontal directions being represented closer to the rostral pole. Tuned auditory units in the intermediate layers of the superior colliculus, however, showed no systematic spatial arrangement. This pattern was confirmed by analysing best azimuth directions from simultaneously recorded units. Our results indicate that the rat superior colliculus contains a representation of auditory space which is similar to that described for other small mammals.

["QT" pacemaker in aggregate exchange. Do old electrodes impair functional ability?]. / "QT"-Schrittmacher bei Aggregataustausch. Schränken alte Elektroden die Funktionsfähigkeit ein?

A "QT"-interval driven rate responsive pacemaker can also be implanted on the occasion of pacemaker replacement. To evaluate the electrophysiological properties and limitations of chronic leads, in 30 patients the evoked intracardiac electrogram was recorded via the chronic lead during pacemaker replacement (14 different types, mean interval after implantation 111 (25-171 months). T-wave detectability was evaluated with different pulse amplitudes (2.5 and 5.0 V) and two pacemaker systems (TX 915, Rhythmyx) with different "fast recharge" mechanisms. In particular, the T-wave signal was influenced by capacitor discharge effects. At 2.5 V output T-wave amplitude was greater than or equal to 1.5 mV in all (19) patients, who could be paced at this voltage. However, at 5 V in 9/30 patients T-wave was less than 1 mV and detection was not possible in 6/30 cases. During pacing with the newly developed "QT"-interval driven, rate-responsive pacemaker (Rhythmyx) with two fast recharge pulses, in nine investigated patients the T-wave was markedly better discriminable compared to the TX 915 pacemaker. Accordingly, in 37 patients with implanted "QT"-controlled pacemakers (TX 911): n = 13; TX 915: n = 21; Rhythmyx: n = 3. Indication for pacemaker therapy: high degree AV block: n = 24, sick-sinus syndrome: n = 13) reliable T-wave sensing was possible at 2.5 V/0.2 ms output, whereas at 5 V/2 ms no T-wave sensing could be achieved in 8/37 cases. On the occasion of pacemaker replacement the "QT"-controlled pacemaker can be implanted without intraoperative measurements, whenever a pulse amplitude less than 2.5 V is sufficient for stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

The differentiation-pattern in dependence of the proportion between inducing and induced cells studied on gastrula-ectoderm of Ambystoma mexicanum.

The dependence of the differentiation-pattern of competent amphibian ectoderm on the proportion of inducing and induced material was studied. To do so different masses of LiCl-treated tissue were combined with a constant mass of untreated material. LiCl-treated isolates corresponding in size with the treated portions in the combinations served as controls. The experiments seem to show at least three factors responsible for the differentiation-pattern of the combinations: the number of inducing cells, the number of cells to be induced, and the competence of the ectoderm, which depends on the stage of development.