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BDNF haploinsufficiency induces behavioral endophenotypes of schizophrenia in male mice that are rescued by enriched environment

Fri, 01 Jan 2021 00:00:00 GMT

Title: BDNF haploinsufficiency induces behavioral endophenotypes of schizophrenia in male mice that are rescued by enriched environment Author(s): Harb, Mahmoud; Jagusch, Justina; Durairaja, Archana; Endres, Thomas; Leßmann, Volkmar; Fendt, Markus Abstract: Brain-derived neurotrophic factor (BDNF) is implicated in a number of processes that are crucial for healthy functioning of the brain. Schizophrenia is associated with low BDNF levels in the brain and blood, however, not much is known about BDNF’s role in the different symptoms of schizophrenia. Here, we used BDNF-haploinsufficient (BDNF+/−) mice to investigate the role of BDNF in different mouse behavioral endophenotypes of schizophrenia. Furthermore, we assessed if an enriched environment can prevent the observed changes. In this study, male mature adult wild-type and BDNF+/− mice were tested in mouse paradigms for cognitive flexibility (attentional set shifting), sensorimotor gating (prepulse inhibition), and associative emotional learning (safety and fear conditioning). Before these tests, half of the mice had a 2-month exposure to an enriched environment, including running wheels. After the tests, BDNF brain levels were quantified. BDNF+/− mice had general deficits in the attentional set-shifting task, increased startle magnitudes, and prepulse inhibition deficits. Contextual fear learning was not affected but safety learning was absent. Enriched environment housing completely prevented the observed behavioral deficits in BDNF+/− mice. Notably, the behavioral performance of the mice was negatively correlated with BDNF protein levels. These novel findings strongly suggest that decreased BDNF levels are associated with several behavioral endophenotypes of schizophrenia. Furthermore, an enriched environment increases BDNF protein to wild-type levels and is thereby able to rescue these behavioral endophenotypes.

Studying Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis with 7-T magnetic resonance

Fri, 01 Jan 2021 00:00:00 GMT

Title: Studying Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis with 7-T magnetic resonance Author(s): Düzel, Emrah; Costagli, Mauro; Donatelli, Graziella; Speck, Oliver; Cosottini, Mirco Abstract: Ultra-high-field (UHF) magnetic resonance (MR) scanners, that is, equipment operating at static magnetic field of 7 tesla (7 T) and above, enable the acquisition of data with greatly improved signal-to-noise ratio with respect to conventional MR systems (e.g., scanners operating at 1.5 T and 3 T). The change in tissue relaxation times at UHF offers the opportunity to improve tissue contrast and depict features that were previously inaccessible. These potential advantages come, however, at a cost: in the majority of UHF-MR clinical protocols, potential drawbacks may include signal inhomogeneity, geometrical distortions, artifacts introduced by patient respiration, cardiac cycle, and motion. This article reviews the 7 T MR literature reporting the recent studies on the most widespread neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis.

„Wut im Ohr“: Misophonie : Übersicht und aktueller Wissensstand

Sat, 01 Jan 2022 00:00:00 GMT

Title: „Wut im Ohr“: Misophonie : Übersicht und aktueller Wissensstand Author(s): Schwemmle, Cornelia Christiane; Arens, Christoph Abstract: Die Misophonie ist eine Intoleranz auf bestimmte Alltagsgeräusche. Hierbei fungieren als „Trigger“ „menschliche Körpergeräusche“, z. B. Schlucken/Schmatzen/Atemgeräusche oder Geräusche, die von Menschen, aber nicht vom menschlichen Körper erzeugt werden (z. B. Klicken Kugelschreiberknopf ), ferner Tier-/Maschinengeräusche. Die Betroffenen verspüren sofort eine negativemotionale Reaktion wie Wut, Aggression, Ekel u.a. Objektivierbare Veränderungen sind Herzfrequenzerhöhung und Blutdruckveränderungen. Die emotionale Reaktion ist individuell und hängt z. B. von Geräuschart, persönlicher Vorerfahrung, sozialem Kontext oder psychologischem Profil ab. Die Misophonie ist bisher als Krankheit nicht definiert und keinem offiziellen Diagnosesystem zugeordnet, sie scheint eine eigenständige Störung zu sein: Assoziationen bestehen u. a. mit Aufmerksamkeits-/Zwangsstörungen, Tinnitus, Hyperakusis, Autismus- Spektrum-Krankheiten. Definitionskriterien wurden 2013 veröffentlicht; verschiedene, validierte Fragebögen wurden bisher zur Misophonieausprägung entwickelt. Studien mit funktionellenMRT-Untersuchungen des Kopfes zeigten eine übermäßige Aktivierung des anterioren Inselkortex (AIC) und seiner benachbarten Regionen, die für Emotionsverarbeitung/- regulation verantwortlich sind. Bisher gibt es keine randomisierten kontrollierten Studien zur Therapie. Einzelne Publikationen beschreiben kognitive Verhaltensinterventionen, Retrainingtherapien und Schallmaskierungssysteme. Zur Triggerreduktion werden Ohrstöpsel/Musikkopfhörer verwendet. Auch HNO-Ärzte können mit Misophoniepatienten konfrontiert werden, z. B. zur Klärung des Hörvermögens oder Beratung von Therapiemöglichkeiten. Der Bericht stellt eine Übersicht des aktuellen Wissensstands zur Misophonie sowie ihrer Diagnostik und Therapie dar.

Cortical hemodynamics as a function of handgrip strength and cognitive performance : a cross-sectional fNIRS study in younger adults

Fri, 01 Jan 2021 00:00:00 GMT

Title: Cortical hemodynamics as a function of handgrip strength and cognitive performance : a cross-sectional fNIRS study in younger adults Author(s): Herold, Fabian; Behrendt, Tom; Törpel, Alexander; Hamacher, Dennis; Müller, Notger Germar; Schega, Lutz Abstract: Background: There is growing evidence for a positive correlation between measures of muscular strength and cognitive abilities. However, the neurophysiological correlates of this relationship are not well understood so far. The aim of this study was to investigate cortical hemodynamics [i.e., changes in concentrations of oxygenated (oxyHb) and deoxygenated hemoglobin (deoxyHb)] as a possible link between measures of muscular strength and cognitive performance. Methods: In a cohort of younger adults (n = 39, 18–30 years), we assessed (i) handgrip strength by a handhold dynamometer, (ii) short-term working memory performance by using error rates and reaction times in the Sternberg task, and (iii) cortical hemodynamics of the prefrontal cortex (PFC) via functional near-infrared spectroscopy (fNIRS). Results: We observed low to moderate negative correlations ( rp = ~ − 0.38 to − 0.51; p < 0.05) between reaction time and levels of oxyHb in specific parts of the PFC. Furthermore, we noticed low to moderate positive correlations ( rp = ~ 0.34 to 0.45; p < 0.05) between reaction times and levels of deoxyHb in distinct parts of the PFC. Additionally, higher levels of oxyHb ( rp (35) = 0.401; p = 0.014) and lower levels of deoxyHb ( rp (34) = − 0.338; p = 0.043) in specific parts of the PFC were linked to higher percentage of correct answers. We also found low to moderate correlations (p < 0.05) between measures of handgrip strength and levels of oxyHb ( rp = ~ 0.35; p < 0.05) and levels of deoxyHb ( rp = ~ − 0.25 to − 0.49; p < 0.05) in specific parts of the PFC. However, there was neither a correlation between cognitive performance and handgrip strength nor did cortical hemodynamics in the PFC mediate the relationship between handgrip strength and cognitive performance (p > 0.05). Conclusion: The present study provides evidence for a positive neurobehavioral relationship between cortical hemodynamics and cognitive performance. Our findings further imply that in younger adults higher levels of handgrip strength positively influence cortical hemodynamics although the latter did not necessarily culminate in better cognitive performance. Future research should examine whether the present findings can be generalized to other cohorts (e.g., older adults).