Assessment of perfusion deficit with early phases of [18F]PI-2620 tau-PET versus [18F]flutemetamol-amyloid-PET recordings

Purpose Characteristic features of amyloid-PET (A), tau-PET (T), and FDG-PET (N) can serve for the A/T/N classification of neurodegenerative diseases. Recent studies showed that the early, perfusion-weighted phases of amyloid- or tau-PET recordings serve to detect cerebrometabolic deficits equally to FDG-PET, therefore providing a surrogate of neuronal injury. As such, two channels of diagnostic information can be obtained in the setting of a single PET scan. However, there has hitherto been no comparison of early-phase amyloid- and tau-PET as surrogates for deficits in perfusion/metabolism. Therefore, we undertook to compare [18F]flutemetamol-amyloid-PET and [18F]PI-2620 tau-PET as “one-stop shop” dual purpose tracers for the detection of neurodegenerative disease. Methods We obtained early-phase PET recordings with [18F]PI-2620 (0.5–2.5 min p.i.) and [18F]flutemetamol (0–10 min p.i.) in 64 patients with suspected neurodegenerative disease. We contrasted global mean normalized images (SUVr) in the patients with a normal cohort of 15 volunteers without evidence of increased pathology to β-amyloid- and tau-PET examinations. Regional group differences of tracer uptake (z-scores) of 246 Brainnetome volumes of interest were calculated for both tracers, and the correlations of the z-scores were evaluated using Pearson’s correlation coefficient. Lobar compartments, regions with significant neuronal injury (z-scores <  − 3), and patients with different neurodegenerative disease entities (e.g., Alzheimer’s disease or 4R-tauopathies) served for subgroup analysis. Additionally, we used partial regression to correlate regional perfusion alterations with clinical scores in cognition tests. Results The z-scores of perfusion-weighted images of both tracers showed high correlations across the brain, especially in the frontal and parietal lobes, which were the brain regions with pronounced perfusion deficit in the patient group (R = 0.83 ± 0.08; range, 0.61–0.95). Z-scores of individual patients correlated well by region (R = 0.57 ± 0.15; range, 0.16–0.90), notably when significant perfusion deficits were present (R = 0.66 ± 0.15; range, 0.28–0.90). Conclusion The early perfusion phases of [18F]PI-2620 tau- and [18F]flutemetamol-amyloid-PET are roughly equivalent indices of perfusion defect indicative of regional and lobar neuronal injury in patients with various neurodegenerative diseases. As such, either tracer may serve for two diagnostic channels by assessment of amyloid/tau status and neuronal activity

Cutaneous lesions of the external ear

Skin diseases on the external aspect of the ear are seen in a variety of medical disciplines. Dermatologists, othorhinolaryngologists, general practitioners, general and plastic surgeons are regularly consulted regarding cutaneous lesions on the ear

New Caledonian crows rapidly solve a collaborative problem without cooperative cognition

There is growing comparative evidence that the cognitive bases of cooperation are not unique to humans. However, the selective pressures that lead to the evolution of these mechanisms remain unclear. Here we show that while tool-making New Caledonian crows can produce collaborative behavior, they do not understand the causality of cooperation nor show sensitivity to inequity. Instead, the collaborative behavior produced appears to have been underpinned by the transfer of prior experience. These results suggest that a number of possible selective pressures, including tool manufacture and mobbing behaviours, have not led to the evolution of cooperative cognition in this species. They show that causal cognition can evolve in a domain specific manner-understanding the properties and flexible uses of physical tools does not necessarily enable animals to grasp that a conspecific can be used as a social tool

The evolution of primate short-term memory

Short-term memory is implicated in a range of cognitive abilities and is critical for understanding primate cognitive evolution. To investigate the effects of phylogeny, ecology and sociality on short-term memory, we tested the largest and most diverse primate sample to date (421 non-human primates across 41 species) in an experimental delayed-response task. Our results confirm previous findings that longer delays decrease memory performance across species and taxa. Our analyses demonstrate a considerable contribution of phylogeny over ecological and social factors on the distribution of short-term memory performance in primates; closely related species had more similar short-term memory abilities. Overall, individuals in the branch of Hominoidea performed better compared to Cercopithecoidea, who in turn performed above Platyrrhini and Strepsirrhini. Interdependencies between phylogeny and socioecology of a given species presented an obstacle to disentangling the effects of each of these factors on the evolution of shortterm memory capacity. However, this study offers an important step forward in understanding the interspecies and individual variation in short-term memory ability by providing the first phylogenetic reconstruction of this trait’s evolutionary history. The dataset constitutes a unique resource for studying the evolution of primate cognition and the role of short-term memory in other cognitive abilities

Intra- und crossmodales Reorganisationsmuster bei Presbyakusis

Hintergrund: Der Verlust eines Sinnessystems führt zu Umbauprozessen im Gehirn. Ziel der Studie war es, die intra- und crossmodale kortikale Reorganisation bei Vorliegen einer gering- bzw. hochgradigen Schwerhörigkeit zu untersuchen.Material und Methoden: Eingeschlossen wurden 77 Probanden im Alter von 62.39 Jahren (SD 7.56): 36 Normalhörende, 23 gering- und 18 hochgradig Schwerhörige. Nach Gabe eines auditiven (Silbe/ba/ bei 65 dB) bzw. eines visuellen Stimulus (Wechsel von zwei Schwarz-Weiß-Mustern) erfolgte die Ableitung der auditiv und visuell evozierten Potenziale über ein 29-Kanal-EEG. Analysiert wurden neben Amplitude und Latenz der P100-, N100- und P200-Komponenten die auditiven und visuellen Hirnregionen (Brodman-Areale 41, 42 und 18) mittels sLORETA. Darüber hinaus wurde bei den mit einem CI versorgten hochgradig Schwerhörigen das Sprachverstehen in Ruhe und im Störgeräusch (Freiburger Einsilbertest/OLSA) bestimmt.Ergebnisse: Im Vergleich zur Kontrollgruppe wiesen die geringgradig Schwerhörigen eine altersunabhängig verlängerte Latenz der P200-Komponente (p=.036) in den auditorisch evozierten Potenzialen auf. Darüber hinaus zeigte die EEG-Quellenanalyse eine Umverteilung der kortikalen Ressourcen in den auditorischen Arealen von einer linksseitig dominierten Verarbeitung bei den Normalhörenden (p=.028) zu einer bilateral ausgeglichenen Verarbeitung bei den geringgradig Schwerhörigen. Nach visueller Stimulation fand sich eine verstärkte linkshemisphärische ROI-Aktivität in den Brodman-Arealen 41 und 42 bei den hochgradig im Vergleich zu den geringgradig Schwerhörigen (p=.032) und den Kontrollprobanden (p=.021). Daneben zeigten Gehörlose signifikant größere Amplituden der P100- und P200-Komponente an Position Po8 (p=.002) und Po7 (p=.006) im Vergleich zu den hochgradig Schwerhörigen und den Kontrollprobanden. Auch korrelierte die Aktivität in den auditorischen ROIs mit dem Sprachverstehen 6 Monaten nach Cochlea Implantation in Ruhe (p=.02, r=0.591) und im Störschall (p=.007, r=-0.784).Fazit: Bereits bei Vorliegen einer geringgradigen Schwerhörigkeit findet eine ausgeprägte kortikale Reorganisation statt. Dies unterstreicht die Notwendigkeit einer frühzeitigen Diagnostik und Versorgung der Presbyakusis. Daneben scheint die cross-modale Plastizität adaptiv im Hinblick auf das p.o. Outcome nach einer Implantation zu sein. Hieraus könnten sich in Zukunft neue Konzepte in der Rehabilitation ergeben