Publications by authors named "Gereon R Fink"

570 Publications

An individualized functional magnetic resonance imaging protocol to assess semantic congruency effects on episodic memory in an aging multilingual population.

Front Aging Neurosci 2022 22;14:873376. Epub 2022 Jul 22.

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Forschungszentrum Jülich, Jülich, Germany.

The cognitive stimulation induced by multilingualism may slow down age-related memory impairment. However, a suitable neuroscientific framework to assess the influence of multilingualism on age-related memory processes is missing. We propose an experimental paradigm that assesses the effects of semantic congruency on episodic memory using functional magnetic resonance imaging (fMRI). To this end, we modified the picture-word interference (PWI) task to be suitable for the assessment of older multilingual subjects undergoing fMRI. In particular, stimulus materials were prepared in multiple languages (French, German, Luxembourgish, English) and closely matched in semantic properties, thus enabling participants to perform the experiment in a language of their choice. This paradigm was validated in a group ( = 62) of healthy, older participants (over 64 years) who were multilingual, all practicing three or more languages. Consistent with the engagement of semantic congruency processes, we found that the encoding and recognition of semantically related vs. unrelated picture-word pairs evoked robust differences in behavior and the neural activity of parietal-temporal networks. These effects were negligibly modulated by the language used to perform the task. Based on this validation in a multilingual population, we conclude that the proposed paradigm will allow future studies to evaluate whether multilingualism aptitude engages neural systems in a manner that protects long-term memory from aging-related decline.
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http://dx.doi.org/10.3389/fnagi.2022.873376DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9354990PMC
July 2022

Imaging the neural underpinnings of freezing of gait in Parkinson's disease.

Neuroimage Clin 2022 Jul 25;35:103123. Epub 2022 Jul 25.

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Forschungszentrum Jülich, Jülich, Germany; Department of Neurology, University Hospital Cologne and Faculty of Medicine, University of Cologne, Cologne, Germany. Electronic address:

Freezing of gait (FoG) is a paroxysmal and sporadic gait impairment that severely affects PD patients' quality of life. This review summarizes current neuroimaging investigations that characterize the neural underpinnings of FoG in PD. The review presents and discusses the latest advances across multiple methodological domains that shed light on structural correlates, connectivity changes, and activation patterns associated with the different pathophysiological models of FoG in PD. Resting-state fMRI studies mainly report cortico-striatal decoupling and disruptions in connectivity along the dorsal stream of visuomotor processing, thus supporting the 'interference' and the 'perceptual dysfunction' models of FoG. Task-based MRI studies employing virtual reality and motor imagery paradigms reveal a disruption in functional connectivity between cortical and subcortical regions and an increased recruitment of parieto-occipital regions, thus corroborating the 'interference' and 'perceptual dysfunction' models of FoG. The main findings of fNIRS studies of actual gait primarily reveal increased recruitment of frontal areas during gait, supporting the 'executive dysfunction' model of FoG. Finally, we discuss how identifying the neural substrates of FoG may open new avenues to develop efficient treatment strategies.
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http://dx.doi.org/10.1016/j.nicl.2022.103123DOI Listing
July 2022

Neuropsychological Evidence for a Motor Working Memory Subsystem Related to Apraxia.

J Cogn Neurosci 2022 Jul 22:1-12. Epub 2022 Jul 22.

Forschungszentrum Jülich.

Recent evidence in healthy participants suggests that a motor subcomponent of working memory (mWM) may exist. We investigated whether this mWM is impaired in patients with a motor-dominant left hemisphere (LH) stroke and apraxia. Furthermore, we hypothesized that a deficient mWM contributes to deficits in motor cognition, that is, apraxia, in LH stroke. The study included 52 patients with LH stroke and 25 age-matched controls. Patients were classified into LH stroke patients with and without apraxia based on deficits in gesture imitation and object use. All participants were examined using the block span test (visuospatial WM), the digit span test (verbal WM), and a novel mWM task. In the latter, participants were presented with static pictures depicting three different actions: actions with objects, meaningless actions, and meaningful actions. In the mWM task, LH stroke patients with apraxia performed worse than age-matched controls. Notably, LH stroke patients with apraxia showed more pronounced mWM deficits than those without apraxia. These results remained significant even after controlling for visuospatial and verbal WM deficits. Regression analyses revealed that LH stroke patients' mWM deficits predicted deficits in imitation. Data provide neuropsychological evidence for a motor subsystem of WM and suggest that deficits in mWM contribute to the severity of apraxia in LH stroke patients.
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http://dx.doi.org/10.1162/jocn_a_01893DOI Listing
July 2022

View Normalization of Object Size in the Right Parietal Cortex.

Vision (Basel) 2022 Jul 1;6(3). Epub 2022 Jul 1.

Institute of Neuroscience and Medicine, INM-3, Research Center Jülich, 52425 Jülich, Germany.

Prior knowledge alters perception already on early levels of processing. For instance, judging the display size of an object is affected by its familiar size. Using functional magnetic resonance imaging, we investigated the neural processes involved in resolving ambiguities between familiar object size and physical object size in 33 healthy human subjects. The familiar size was either small or large, and the object was displayed as either small or large. Thus, the size of the displayed object was either congruent or incongruent with its internally stored canonical size representation. Subjects were asked to indicate where the stimuli appeared on the screen as quickly and accurately as possible, thereby ensuring that differential activations cannot be ascribed to explicit object size judgments. Incongruent (relative to congruent) object displays were associated with enhanced activation of the right intraparietal sulcus (IPS). These data are consistent with but extend previous patient studies, which found the right parietal cortex involved in matching visual objects presented atypically to prototypical object representations, suggesting that the right IPS supports view normalization of objects. In a second experiment, using a parametric design, a region-of-interest analysis supported this notion by showing that increases in size mismatch between the displayed size of an object and its familiar viewing size were associated with an increased right IPS activation. We conclude that the right IPS performs view normalization of mismatched information about the internally stored prototypical size and the current viewing size of an object.
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http://dx.doi.org/10.3390/vision6030041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9326632PMC
July 2022

Two Decades of Brain Tumour Imaging with O-(2-[F]fluoroethyl)-L-tyrosine PET: The Forschungszentrum Jülich Experience.

Cancers (Basel) 2022 Jul 8;14(14). Epub 2022 Jul 8.

Dr. Senckenberg Institute of Neurooncology, University Cancer Center Frankfurt (UCT), Goethe University Hospital, D-60528 Frankfurt am Main, Germany.

O-(2-[F]fluoroethyl)-L-tyrosine (FET) is a widely used amino acid tracer for positron emission tomography (PET) imaging of brain tumours. This retrospective study and survey aimed to analyse our extensive database regarding the development of FET PET investigations, indications, and the referring physicians' rating concerning the role of FET PET in the clinical decision-making process. Between 2006 and 2019, we performed 6534 FET PET scans on 3928 different patients against a backdrop of growing demand for FET PET. In 2019, indications for the use of FET PET were as follows: suspected recurrent glioma (46%), unclear brain lesions (20%), treatment monitoring (19%), and suspected recurrent brain metastasis (13%). The referring physicians were neurosurgeons (60%), neurologists (19%), radiation oncologists (11%), general oncologists (3%), and other physicians (7%). Most patients travelled 50 to 75 km, but 9% travelled more than 200 km. The role of FET PET in decision-making in clinical practice was evaluated by a questionnaire consisting of 30 questions, which was filled out by 23 referring physicians with long experience in FET PET. Fifty to seventy per cent rated FET PET as being important for different aspects of the assessment of newly diagnosed gliomas, including differential diagnosis, delineation of tumour extent for biopsy guidance, and treatment planning such as surgery or radiotherapy, 95% for the diagnosis of recurrent glioma, and 68% for the diagnosis of recurrent brain metastases. Approximately 50% of the referring physicians rated FET PET as necessary for treatment monitoring in patients with glioma or brain metastases. All referring physicians stated that the availability of FET PET is essential and that it should be approved for routine use. Although the present analysis is limited by the fact that only physicians who frequently referred patients for FET PET participated in the survey, the results confirm the high relevance of FET PET in the clinical diagnosis of brain tumours and support the need for its approval for routine use.
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http://dx.doi.org/10.3390/cancers14143336DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9319157PMC
July 2022

[The Cost of Early Diagnosis of Cognitive Decline in German Memory Clinics].

Fortschr Neurol Psychiatr 2022 Jul 20;90(7-08):361-367. Epub 2022 Jul 20.

Abteilung Gerontopsychiatrie, Zentralinstitut für Seelische Gesundheit, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim.

Dementias are expensive diseases: the net annual cost in European healthcare is about € 28.000 per case with a strong stage dependency, of which medical care accounts for about 19%. Diagnostic costs, on the other hand, account for only a small proportion of the total costs. With changes in the guidelines, biomarker tests are becoming increasingly important. At present, the concrete economic impact of biomarker-based diagnosis is largely unknown. To determine the actual costs of diagnostic procedures based on guidelines, we conducted a survey among the members of the German Memory Clinic Network (DNG). From 15 expert centres, the staff engagement time for all procedures was collected. Based on the individual engagement times of the different professions, the total of personnel costs for diagnostics was calculated using current gross personnel costs. The total sum of diagnostic costs (personnel plus procedures) was calculated for three different scenarios e. g. € 633,97 for diagnostics without biomarkers, € 1.214,90 for diagnostics with CSF biomarkers and € 4.740,58 € for diagnostics with FDG- plus Amyloid-PET. In addition, the actual diagnostic costs of the current practice in expert memory clinics were estimated, taking into account personnel costs, costs for the different procedures and the frequency of their use across all patients. This results in total average costs of € 1.394,43 per case as the mean across all centres (personnel costs € 351,72, costs for diagnostic procedures € 1.042,71). The results show that state-of-the-art diagnosis of dementia and pre-dementia states, such as mild cognitive impairment (MCI) requires financial resources, which are currently not fully reimbursed in Germany. The need for a biomarker-based etiological diagnosis of dementia and pre-dementia states will increase, due to availability of disease-modifying treatments. Therefore, the current gap of reimbursement must be filled by new models of compensation.
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http://dx.doi.org/10.1055/a-1871-9889DOI Listing
July 2022

Antibody response after COVID-19 vaccination in intravenous immunoglobulin-treated immune neuropathies.

Eur J Neurol 2022 Jul 16. Epub 2022 Jul 16.

Department of Neurology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany.

Background And Purpose: This study assessed the prevalence of anti-SARS-CoV-2 antibodies in therapeutic immunoglobulin and their impact on serological response to COVID-19 mRNA vaccine in patients with intravenous immunoglobulin (IVIg)-treated chronic immune neuropathies.

Methods: Forty-six samples of different brands or lots of IVIg or subcutaneous IgG were analyzed for anti-SARS-CoV-2 IgG using enzyme-linked immunosorbent assay and chemiluminescent microparticle immunoassay. Blood sera from 16 patients with immune neuropathies were prospectively analyzed for anti-SARS-CoV-2 IgA, IgG, and IgM before and 1 week after IVIg infusion subsequent to consecutive COVID-19 mRNA vaccine doses and after 12 weeks. These were compared to 42 healthy subjects.

Results: Twenty-four (52%) therapeutic immunoglobulin samples contained anti-SARS-CoV-2 IgG. All patients with immune neuropathies (mean age = 65 ± 16 years, 25% female) were positive for anti-SARS-CoV-2 IgG after COVID-19 vaccination. Anti-SARS-CoV-2 IgA titers significantly decreased 12-14 weeks after vaccination (p = 0.02), whereas IgG titers remained stable (p = 0.2). IVIg did not significantly reduce intraindividual anti-SARS-CoV-2 IgA/IgG serum titers in immune neuropathies (p = 0.69). IVIg-derived anti-SARS-CoV-2 IgG did not alter serum anti-SARS-CoV-2 IgG decrease after IVIg administration (p = 0.67).

Conclusions: Our study indicates that IVIg does not impair the antibody response to COVID-19 mRNA vaccine in a short-term observation, when administered a minimum of 2 weeks after each vaccine dose. The infusion of current IVIg preparations that contain anti-SARS-CoV-2 IgG does not significantly alter serum anti-SARS-CoV-2 IgG titers.
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http://dx.doi.org/10.1111/ene.15508DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9349681PMC
July 2022

Terminal H-reflex Measurements in Mice.

J Vis Exp 2022 06 16(184). Epub 2022 Jun 16.

Faculty of Medicine and University Hospital Cologne, Department of Neurology, University of Cologne;

The Hoffmann reflex (H-reflex), as an electrical analog to the stretch reflex, allows electrophysiological validation of the integrity of neural circuits after injuries such as spinal cord damage or stroke. An increase of the H-reflex response, together with symptoms like non-voluntary muscle contractions, pathologically augmented stretch reflex, and hypertonia in the corresponding muscle, is an indicator of post-stroke spasticity (PSS). In contrast to rather nerve-unspecific transcutaneous measurements, here, we present a protocol to quantify the H-reflex directly at the ulnar and median nerves of the forepaw, which is applicable, with minor modifications, to the tibial and sciatic nerve of the hindpaw. Based on the direct stimulation and the adaptation to different nerves, the method represents a reliable and versatile tool to validate electrophysiological changes in spasticity-related disease models.
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http://dx.doi.org/10.3791/63304DOI Listing
June 2022

Impaired body-centred sensorimotor transformations in congenitally deaf people.

Brain Commun 2022 7;4(3):fcac148. Epub 2022 Jun 7.

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Wilhelm-Johnen-Strasse, 52428 Jülich, Germany.

Congenital deafness modifies an individual's daily interaction with the environment and alters the fundamental perception of the external world. How congenital deafness shapes the interface between the internal and external worlds remains poorly understood. To interact efficiently with the external world, visuospatial representations of external target objects need to be effectively transformed into sensorimotor representations with reference to the body. Here, we tested the hypothesis that egocentric body-centred sensorimotor transformation is impaired in congenital deafness. Consistent with this hypothesis, we found that congenital deafness induced impairments in egocentric judgements, associating the external objects with the internal body. These impairments were due to deficient body-centred sensorimotor transformation , rather than the reduced fidelity of the visuospatial representations of the egocentric positions. At the neural level, we first replicated the previously well-documented critical involvement of the frontoparietal network in egocentric processing, in both congenitally deaf participants and hearing controls. However, both the strength of neural activity and the intra-network connectivity within the frontoparietal network alone could not account for egocentric performance variance. Instead, the inter-network connectivity between the task-positive frontoparietal network and the task-negative default-mode network was significantly correlated with egocentric performance: the more cross-talking between them, the worse the egocentric judgement. Accordingly, the impaired egocentric performance in the deaf group was related to increased inter-network connectivity between the frontoparietal network and the default-mode network and decreased intra-network connectivity within the default-mode network. The altered neural network dynamics in congenital deafness were observed for both evoked neural activity during egocentric processing and intrinsic neural activity during rest. Our findings thus not only demonstrate the optimal network configurations between the task-positive and -negative neural networks underlying coherent body-centred sensorimotor transformations but also unravel a critical cause (i.e. impaired body-centred sensorimotor transformation) of a variety of hitherto unexplained difficulties in sensory-guided movements the deaf population experiences in their daily life.
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http://dx.doi.org/10.1093/braincomms/fcac148DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9240416PMC
June 2022

Efficacy and tolerability of regorafenib in pretreated patients with progressive CNS grade 3 or 4 gliomas.

J Neurooncol 2022 Jun 18. Epub 2022 Jun 18.

Deptartment of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener St. 62, 50937, Cologne, Germany.

Background: The phase 2 REGOMA trial suggested an encouraging overall survival benefit in glioblastoma patients at first relapse treated with the multikinase inhibitor regorafenib. Here, we evaluated the efficacy and side effects of regorafenib in a real-life setting.

Methods: From 2018 to 2021, 30 patients with progressive WHO CNS grade 3 or 4 gliomas treated with regorafenib (160 mg/day; first 3 weeks of each 4-week cycle) with individual dose adjustment depending on toxicity were retrospectively identified. Side effects were evaluated according to the Common Terminology Criteria for Adverse Events (version 5.0). MRI was obtained at baseline and after every second cycle. Tumor progression was assessed according to RANO criteria. After regorafenib initiation, the median PFS and OS were calculated.

Results: The median number of treatment lines before regorafenib was 2 (range 1-4). Most patients (73%) had two or more pretreatment lines. At first relapse, 27% of patients received regorafenib. A total of 94 regorafenib cycles were administered (median 2 cycles; range 1-9 cycles). Grade 3 and 4 side effects were observed in 47% and 7% of patients, respectively, and were not significantly increased in patients with two or more pretreatments (P > 0.05). The most frequent grade 3 or 4 side effects were laboratory abnormalities (62%). PFS was 2.6 months (range 0.8-8.2 months), and the OS was 6.2 months (range 0.9-24 months).

Conclusions: In patients with progressive WHO grade 3 or 4 gliomas, predominantly with two pretreatment lines or more, regorafenib seems to be effective despite considerable grade 3 or 4 side effects.
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http://dx.doi.org/10.1007/s11060-022-04066-9DOI Listing
June 2022

Intranasal oxytocin attenuates the effects of monetary feedback on procedural learning.

Psychoneuroendocrinology 2022 Sep 3;143:105823. Epub 2022 Jun 3.

Institute of Neuroscience and Medicine (INM-3), Forschungszentrum Jülich, Jülich, Germany; University of Cologne, Faculty of Medicine and University Hospital Cologne, Department of Neurology, Germany.

Procedural learning is a vital brain function that allows us to acquire motor skills during development or re-learn them after lesions affecting the motor system. Procedural learning can be improved by feedback of different valence, e.g., monetary or social, mediated by dopaminergic circuits. While processing motivationally relevant stimuli, dopamine interacts closely with oxytocin, whose effects on procedural learning, particularly feedback-based approaches, remain poorly understood. In a randomized, double-blind, placebo-controlled trial, we investigated whether oxytocin modulates the differential effects of monetary and social feedback on procedural learning. Sixty-one healthy male participants were randomized to receive a placebo or oxytocin intranasally. The participants then performed a modified serial reaction time task. Oxytocin plasma concentrations were measured before and after applying the placebo or verum. Groups did not differ regarding general reaction times or measures of procedural learning. For the placebo group, monetary feedback improved procedural learning compared to a neutral control condition. In contrast, the oxytocin group did not show a differential effect of monetary or social feedback despite a significant increase in oxytocin plasma levels after intranasal application. The data suggest that oxytocin does not influence procedural learning per se. Instead, oxytocin seems to attenuate the effects of monetary feedback on procedural learning specifically.
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http://dx.doi.org/10.1016/j.psyneuen.2022.105823DOI Listing
September 2022

Decreased Efficiency of Between-Network Dynamics During Early Memory Consolidation With Aging.

Front Aging Neurosci 2022 16;14:780630. Epub 2022 May 16.

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany.

Aging is associated with memory decline and progressive disabilities in the activities of daily living. These deficits have a significant impact on the quality of life of the aging population and lead to a tremendous burden on societies and health care systems. Understanding the mechanisms underlying aging-related memory decline is likely to inform the development of compensatory strategies promoting independence in old age. Research on aging-related memory decline has mainly focused on encoding and retrieval. However, some findings suggest that memory deficits may at least partly be due to impaired consolidation. To date, it remains elusive whether aging-related memory decline results from defective consolidation. This study examined age effects on consolidation-related neural mechanisms and their susceptibility to interference using functional magnetic resonance imaging data from 13 younger (20-30 years, 8 female) and 16 older (49-75 years, 5 female) healthy participants. fMRI was performed before and during a memory paradigm comprised of encoding, consolidation, and retrieval phases. Consolidation was variously challenged: (1) control (no manipulation), (2) interference (repeated stimulus presentation with interfering information), and (3) reminder condition (repeated presentation without interfering information). We analyzed the fractional amplitude of low-frequency fluctuations (fALFF) to compare brain activity changes from pre- to post-encoding rest. In the control condition, fALFF was decreased in the left supramarginal gyrus, right middle temporal gyrus, and left precuneus but increased in parts of the occipital and inferior temporal cortex. Connectivity analyses between fALFF-derived seeds and network ROIs revealed an aging-related decrease in the efficiency of functional connectivity (FC) within the ventral stream network and between salience, default mode, and central executive networks during consolidation. Moreover, our results indicate increased interference susceptibility in older individuals with dynamics between salience and default mode networks as a neurophysiological correlate. Conclusively, aging-related memory decline is partly caused by inefficient consolidation. Memory consolidation requires a complex interplay between large-scale brain networks, which qualitatively decreases with age.
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http://dx.doi.org/10.3389/fnagi.2022.780630DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9148994PMC
May 2022

The capacity and organization of gustatory working memory.

Sci Rep 2022 05 16;12(1):8056. Epub 2022 May 16.

Cognitive Neuroscience (INM-3), Institute of Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany.

Remembering a particular taste is crucial in food intake and associative learning. We investigated whether taste can be dynamically encoded, maintained, and retrieved on short time scales consistent with working memory (WM). We use novel single and multi-item taste recognition tasks to show that a single taste can be reliably recognized despite repeated oro-sensory interference suggesting active and resilient maintenance (Experiment 1, N = 21). When multiple tastes were presented (Experiment 2, N = 20), the resolution with which these were maintained depended on their serial position, and recognition was reliable for up to three tastes suggesting a limited capacity of gustatory WM. Lastly, stimulus similarity impaired recognition with increasing set size, which seemed to mask the awareness of capacity limitations. Together, the results advocate a hybrid model of gustatory WM with a limited number of slots where items are stored with varying precision.
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http://dx.doi.org/10.1038/s41598-022-12005-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9110745PMC
May 2022

Association of intraventricular fibrinolysis with clinical outcomes in ICH: an individual participant data meta-analysis.

Stroke 2022 May 6. Epub 2022 May 6.

Department of Neurology, Klinikum Dortmund, GERMANY.

In patients with intracerebral hemorrhage (ICH) the presence of intraventricular hemorrhage (IVH) constitutes an important therapeutic target. Intraventricular fibrinolysis (IVF) reduces mortality, yet impact on functional disability remains unclear. Thus, we aimed to determine the influence of IVF on functional outcomes. This individual participant data (IPD) meta-analysis pooled 1,501 patients from two randomized trials and seven observational studies enrolled during 2004 to 2015. We compared IVF vs standard of care (SoC, including placebo) in patients treated with external ventricular drainage due to acute hydrocephalus caused by ICH and/or IVH. The primary outcome was functional disability evaluated by the modified Rankin Scale (mRS, range:0-6, lower scores indicating less disability) at 6 months, dichotomized into mRS:0-3 vs mRS:4-6. Secondary outcomes included ordinal-shift analysis, all-cause mortality, and intracranial adverse events. Confounding and bias were adjusted by random-effects- and doubly-robust-models to calculate odds-ratios (OR) and absolute treatment-effects (ATE). Comparing treatment of 596 with IVF to 905 with SoC resulted in an ATE to achieve the primary outcome of 9.3%[95%CI4.4-14.1]. IVF treatment showed a significant shift towards improved outcome across the entire range of mRS estimates, common-OR:1.75[95%CI1.39-2.17], reduced mortality, OR:0.47[95%CI 0.35-0.64], without increased adverse events, absolute difference:1.0%[95%CI-2.7-4.8]. Exploratory analyses provided that early IVF-treatment (≤48 hours) after symptom onset was associated with an ATE:15.2%[95%CI8.6-21.8] to achieve the primary outcome. As compared to SoC, the administration of IVF in patients with acute hydrocephalus caused by intracerebral and intraventricular hemorrhage significantly improved functional outcome at 6 months. The treatment effect was linked to an early time-window<48h, specifying a target population for future trials.
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http://dx.doi.org/10.1161/STROKEAHA.121.038455DOI Listing
May 2022

[Acute Aortic Dissection: A Life-Threatening Disease Also in Neurological Emergency Medicine].

Fortschr Neurol Psychiatr 2022 May 4. Epub 2022 May 4.

Klinik und Poliklinik für Neurologie, Universität zu Köln, Medizinische Fakultät und Uniklinik Köln, Köln, Germany.

Acute aortic dissection is rare but life-threatening. The symptoms depend on the localization and reduced perfusion of the downstream organs or limbs and are therefore variable. Neurological symptoms may occur that do not immediately lead to a diagnosis and thus delay the necessary therapy. Knowing the early symptoms and warning signs of aortic dissection is therefore also crucial in neurological emergency care for quickly identifying the affected patients and for providing acute therapy. A misdiagnosis with delayed initiation of therapy can significantly worsen the patient's outcome. This study aims to establish a standardized diagnostic and therapeutic algorithm for suspected acute aortic dissection in neurological emergency care. Close interdisciplinary cooperation is mandatory.
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http://dx.doi.org/10.1055/a-1802-3852DOI Listing
May 2022

A Randomized, Double-Blinded Crossover Trial of Short Versus Conventional Pulse Width Subthalamic Deep Brain Stimulation in Parkinson's Disease.

J Parkinsons Dis 2022 ;12(5):1497-1505

Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.

Background: Subthalamic nucleus deep brain stimulation (STN-DBS) is a well-established treatment for patients with Parkinson's disease. Previous acute challenge studies suggested that short pulse widths might increase the therapeutic window while maintaining motor symptom control with a decrease in energy consumption. However, only little is known about the effect of short pulse width stimulation beyond the setting of an acute challenge.

Objective: To compare 4 weeks of STN-DBS with conventional pulse width stimulation (60 μs) to 4 weeks of STN-DBS with short pulse width stimulation (30 μs) regarding motor symptom control.

Methods: This study was a monocentric, double-blinded, randomized crossover non-inferiority trial investigating whether short pulse width stimulation with 30 μs maintains equal motor control as conventional 60 μs stimulation over a period of 4 weeks (German Clinical Trials Register No. DRKS00017528). Primary outcome was the difference in motor symptom control as assessed by a motor diary. Secondary outcomes included energy consumption measures, non-motor effects, side-effects, and quality of life.

Results: Due to a high dropout rate, the calculated sample size of 27 patients was not met and 24 patients with Parkinson's disease and STN-DBS were included in the final analysis. However, there were no differences in any investigated outcome parameter between the two treatment conditions.

Conclusion: This study demonstrates that short pulse width settings (30 μs) provide non-inferior motor symptom control as conventional (60 μs) stimulation without significant differences in energy consumption. Future studies are warranted to evaluate a potential benefit of short pulse width settings in patients with pronounced dyskinesia.
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http://dx.doi.org/10.3233/JPD-213119DOI Listing
January 2022

Recovered grasping performance after stroke depends on interhemispheric frontoparietal connectivity.

Brain 2022 Apr 29. Epub 2022 Apr 29.

Faculty of Medicine and University Hospital Cologne, Department of Neurology, University of Cologne, Cologne, Germany.

Activity changes in the ipsi- and contralesional parietal cortex and abnormal interhemispheric connectivity between these regions are commonly observed after stroke, however, their significance for motor recovery remains poorly understood. We here assessed the contribution of ipsilesional and contralesional anterior intraparietal cortex (aIPS) for hand motor function in eighteen recovered chronic stroke patients and eighteen healthy controls using a multimodal assessment consisting of resting-state fMRI, motor task fMRI, online-rTMS interference, and 3-D movement kinematics. Effects were compared against two control stimulation sites, i.e., contralesional M1 and a sham stimulation condition. We found that patients with good motor outcome compared to patients with more substantial residual deficits featured increased resting-state connectivity between ipsilesional aIPS and contralesional aIPS as well as between ipsilesional aIPS and dorsal premotor cortex. Moreover, interhemispheric connectivity between ipsilesional M1 and contralesional M1 as well as ipsilesional aIPS and contralesional M1 correlated with better motor performance across tasks. TMS interference at individual aIPS and M1 coordinates led to differential effects depending on the motor task that was tested, i.e., index finger-tapping, rapid pointing movements, or a reach-grasp-lift task. Interfering with contralesional aIPS deteriorated the accuracy of grasping, especially in patients featuring higher connectivity between ipsi- and contralesional aIPS. In contrast, interference with the contralesional M1 led to impaired grasping speed in patients featuring higher connectivity between bilateral M1. These findings suggest differential roles of contralesional M1 and aIPS for distinct aspects of recovered hand motor function, depending on the reorganization of interhemispheric connectivity.
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http://dx.doi.org/10.1093/brain/awac157DOI Listing
April 2022

[Brain Stimulation for the Treatment of Dementia].

Fortschr Neurol Psychiatr 2022 Jul 28;90(7-08):336-342. Epub 2022 Apr 28.

Klinik und Poliklinik für Neurologie, Medizinische Fakultät und Uniklinik Köln, Universität zu Köln, Köln, Germany.

Due to the increasing number of cases of Alzheimer's disease and the relatively moderate success with the available symptomatic and causal pharmacological therapies, there is a considerable need to explore non-pharmacological treatment options. In the field of non-invasive brain stimulation (NIBS), various methods have been investigated, particularly transcranial magnetic stimulation and transcranial electrical stimulation. In addition, deep brain stimulation (DBS) is currently being researched as an innovative method for targeted neuromodulation. Both non-invasive and invasive approaches aim to modulate neuronal activity and improve cognitive-mnestic functions. Secondary mechanisms such as long-term potentiation in NIBS or neurogenesis in DBS could also achieve long-term positive effects. Preclinical and clinical studies have already shown promising results in patients in early stages of Alzheimer's disease. However, inconsistent study and stimulation protocols and small sample sizes make it difficult to assess efficacy. Further research is warranted to enable the use of non-invasive or invasive neuromodulatory approaches in clinical practice in the near future.
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http://dx.doi.org/10.1055/a-1787-0335DOI Listing
July 2022

Divergent effects of absolute evidence magnitude on decision accuracy and confidence in perceptual judgements.

Cognition 2022 08 25;225:105125. Epub 2022 Apr 25.

Melbourne School of Psychological Sciences, The University of Melbourne, Australia. Electronic address:

Whether people change their mind after making a perceptual judgement may depend on how confident they are in their decision. Recently, it was shown that, when making perceptual judgements about stimuli containing high levels of 'absolute evidence' (i.e., the overall magnitude of sensory evidence across choice options), people make less accurate decisions and are also slower to change their mind and correct their mistakes. Here we report two studies that investigated whether high levels of absolute evidence also lead to increased decision confidence. We used a luminance judgment task in which participants decided which of two dynamic, flickering stimuli was brighter. After making a decision, participants rated their confidence. We manipulated relative evidence (i.e., the mean luminance difference between the two stimuli) and absolute evidence (i.e., the summed luminance of the two stimuli). In the first experiment, we found that higher absolute evidence was associated with decreased decision accuracy but increased decision confidence. In the second experiment, we additionally manipulated the degree of luminance variability to assess whether the observed effects were due to differences in perceived evidence variability. We replicated the results of the first experiment but did not find substantial effects of luminance variability on confidence ratings. Our findings support the view that decisions and confidence judgements are based on partly dissociable sources of information, and suggest that decisions initially made with higher confidence may be more resistant to subsequent changes of mind.
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http://dx.doi.org/10.1016/j.cognition.2022.105125DOI Listing
August 2022

Gender gap in deep brain stimulation for Parkinson's disease.

NPJ Parkinsons Dis 2022 Apr 20;8(1):47. Epub 2022 Apr 20.

Department of Neurology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.

Previous studies have shown less access to deep brain stimulation (DBS) for Parkinson's disease (PD) in women compared to men raising concerns about a potential gender gap resulting from nonclinical factors or gender differences in clinical efficacy for postoperative quality of life (QoL), motor, and nonmotor symptoms (NMS) outcomes. This was a cross-sectional and a longitudinal, prospective, observational, controlled, quasi-experimental, international multicenter study. A total sample size of 505 consisted of 316 consecutively referred patients for DBS indication evaluation at the University Hospital Cologne (01/2015-09/2020) and 189 consecutively treated patients at DBS centers in the University Hospitals Cologne and Marburg, Salford's Royal Hospital Manchester, and King's College Hospital London. In the cross-sectional cohort, we examined gender proportions at referral, indication evaluations, and DBS surgery. In the longitudinal cohort, clinical assessments at preoperative baseline and 6-month follow-up after surgery included the PD Questionnaire-8, NMSScale, Scales for Outcomes in PD-motor scale, and levodopa-equivalent daily dose. Propensity score matching resulted in a pseudo-randomized sub-cohort balancing baseline demographic and clinical characteristics between women with PD and male controls. 316 patients were referred for DBS. 219 indication evaluations were positive (women n = 102, respectively n = 82). Women with PD were disproportionally underrepresented in referrals compared to the general PD population (relative risk [RR], 0.72; 95%CI, 0.56-0.91; P = 0.002), but more likely to be approved for DBS than men (RR, 1.17; 95%CI, 1.03-1.34; P = 0.029). Nonetheless, their total relative risk of undergoing DBS treatment was 0.74 (95%CI, 0.48-1.12) compared to men with PD. At baseline, women had longer disease duration and worse dyskinesia. Exploring QoL domains, women reported worse mobility and bodily discomfort. At follow-up, all main outcomes improved equally in both genders. Our study provides evidence of a gender gap in DBS for PD. Women and men with PD have distinct preoperative nonmotor and motor profiles. We advocate that more focus should be directed toward the implementation of gender equity as both genders benefit from DBS with equal clinical efficacy. This study provides Class II evidence of beneficial effects of DBS in women with PD compared to male controls.
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http://dx.doi.org/10.1038/s41531-022-00305-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9021281PMC
April 2022

Structural Connectivity of Subthalamic Nucleus Stimulation for Improving Freezing of Gait.

J Parkinsons Dis 2022 ;12(4):1251-1267

Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.

Background: Freezing of gait (FOG) is among the most common and disabling symptoms of Parkinson's disease (PD). Studies show that deep brain stimulation (DBS) of the subthalamic nucleus (STN) can reduce FOG severity. However, there is uncertainty about pathways that need to be modulated to improve FOG.

Objective: To investigate whether STN-DBS effectively reduces FOG postoperatively and whether structural connectivity of the stimulated tissue explains variance of outcomes.

Methods: We investigated 47 patients with PD and preoperative FOG. Freezing prevalence and severity was primarily assessed using the Freezing of Gait Questionnaire (FOG-Q). In a subset of 18 patients, provoked FOG during a standardized walking course was assessed. Using a publicly available model of basal-ganglia pathways we determined stimulation-dependent connectivity associated with postoperative changes in FOG. A region-of-interest analysis to a priori defined mesencephalic regions was performed using a disease-specific normative connectome.

Results: Freezing of gait significantly improved six months postoperatively, marked by reduced frequency and duration of freezing episodes. Optimal stimulation volumes for improving FOG structurally connected to motor areas, the prefrontal cortex and to the globus pallidus. Stimulation of the lenticular fasciculus was associated with worsening of FOG. This connectivity profile was robust in a leave-one-out cross-validation. Subcortically, stimulation of fibers crossing the pedunculopontine nucleus and the substantia nigra correlated with postoperative improvement.

Conclusion: STN-DBS can alleviate FOG severity by modulating specific pathways structurally connected to prefrontal and motor cortices. More differentiated FOG assessments may allow to differentiate pathways for specific FOG subtypes in the future.
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http://dx.doi.org/10.3233/JPD-212997DOI Listing
January 2022

Network analysis of neuroimaging in mice.

Neuroimage 2022 06 17;253:119110. Epub 2022 Mar 17.

University of Cologne, Faculty of Medicine and University Hospital Cologne, Dept. of Neurology, Cologne, Germany; Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Juelich, Germany. Electronic address:

Graph theory allows assessing changes of neuronal connectivity and interactions of brain regions in response to local lesions, e.g., after stroke, and global perturbations, e.g., due to psychiatric dysfunctions or neurodegenerative disorders. Consequently, network analysis based on constructing graphs from structural and functional MRI connectivity matrices is increasingly used in clinical studies. In contrast, in mouse neuroimaging, the focus is mainly on basic connectivity parameters, i.e., the correlation coefficient or fiber counts, whereas more advanced network analyses remain rarely used. This review summarizes graph theoretical measures and their interpretation to describe networks derived from recent in vivo mouse brain studies. To facilitate the entry into the topic, we explain the related mathematical definitions, provide a dedicated software toolkit, and discuss practical considerations for the application to rs-fMRI and DTI. This way, we aim to foster cross-species comparisons and the application of standardized measures to classify and interpret network changes in translational brain disease studies.
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http://dx.doi.org/10.1016/j.neuroimage.2022.119110DOI Listing
June 2022

IGNITE Status Epilepticus Survey: A Nationwide Interrogation about the Current Management of Status Epilepticus in Germany.

J Clin Med 2022 Feb 22;11(5). Epub 2022 Feb 22.

Department of Neurology, Faculty of Medicine, University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany.

We aimed to evaluate the current management of status epilepticus (SE) in intensive care units (ICUs) in Germany, depending on the different hospital levels of care and the ICU specialty. We performed a nationwide web-based anonymized survey, including all German ICUs registered with the German Society for Neurointensive and Emergency Care (Deutsche Gesellschaft für Neurointensiv- und Notfallmedizin; DGNI). The response rate was 83/232 (36%). Continuous EEG monitoring (cEEG) was available in 86% of ICUs. Regular written cEEG reports were obtained in only 50%. Drug management was homogeneous with a general consensus regarding substance order: benzodiazepines-anticonvulsants-sedatives. Thereunder first choice substances were lorazepam (90%), levetiracetam (91%), and propofol (73%). Data suggest that network structures for super-refractory SE are not permeable, as 75% did not transfer SE patients. Our survey provides "real world data" concerning the current management of SE in Germany. Uniform standards in the implementation of cEEG could help further improve the overall quality. Initial therapy management is standardized. For super-refractory SE, a concentration of highly specialized centers establishing network structures analogous to neurovascular diseases seems desirable to apply rescue therapies with low evidence carefully, ideally collecting data on this rare condition in registries and clinical trials.
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http://dx.doi.org/10.3390/jcm11051171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8910893PMC
February 2022

Effects of DRD2/ANKK1 and COMT Val158Met polymorphisms on stabilization against and adaptation to unexpected events.

Cereb Cortex 2022 Mar 2. Epub 2022 Mar 2.

Department of Psychology, University of Muenster, Fliednerstr. 21, Muenster D48149, Germany.

Genetic variations affecting dopaminergic neuromodulation such as the DRD2/ANKK1 and the COMT Val158Met polymorphisms contribute to goal-directed behavior that requires a balance between stabilization and updating of current states and behaviors. Dopamine is also thought to be relevant for encoding of surprise signals to sensory input and adaptive learning. A link between goal-directed behavior and learning from surprise is therefore plausible. In the present fMRI study, we investigated whether DRD2 and COMT polymorphisms are related to behavioral responses and neural signals in the caudate nucleus and dlPFC during updating or stabilizing internal models of predictable digit sequences. To-be-detected switches between sequences and to-be-ignored digit omissions within a sequence varied by information-theoretic quantities of surprise and entropy. We found that A1 noncarriers and Val-carriers showed a lower response threshold along with increased caudate and dlPFC activation to surprising switches compared with A1-carriers and Met-homozygotes, whose dlPFC activity increased with decreasing switch surprise. In contrast, there were overall smaller differences in behavioral and neural modulation by drift surprise. Our results suggest that the impact of dopamine-relevant polymorphisms in the flexibility-stability trade-off may result in part from the role of dopamine in encoding the weight afforded to events requiring updating or stabilization.
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http://dx.doi.org/10.1093/cercor/bhac046DOI Listing
March 2022

Brain Morphometry Associated With Response to Levodopa and Deep Brain Stimulation in Parkinson Disease.

Neuromodulation 2022 Feb 23. Epub 2022 Feb 23.

Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.

Objectives: Whether treatment response in patients with Parkinson disease depends on brain atrophy is insufficiently understood. The goal of this study is to identify specific atrophy patterns associated with response to dopaminergic therapy and deep brain stimulation.

Materials And Methods: In this study, we analyzed the association of gray matter brain atrophy patterns, as identified by voxel-based morphometry, with acute response to levodopa (N = 118) and subthalamic nucleus deep brain stimulation (N = 39). Motor status was measured as a change in points on the Unified Parkinson's Disease Rating Scale III score. Baseline values were obtained before surgery, after cessation of dopaminergic medication for at least 12 hours; response to medication was assessed after administration of a standardized dose of levodopa. Response to deep brain stimulation was measured three months after surgery in the clinical condition after withdrawal of dopaminergic medication.

Results: Although frontoparietal brain gray matter loss was associated with subpar response to deep brain stimulation, there was no significant link between brain atrophy and response to levodopa.

Conclusion: We conclude that response to deep brain stimulation relies on gray matter integrity; hence, gray matter loss may present a risk factor for poor response to deep brain stimulation and may be considered when making decision regarding clinical practice.
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http://dx.doi.org/10.1016/j.neurom.2022.01.013DOI Listing
February 2022

Use of advanced neuroimaging and artificial intelligence in meningiomas.

Brain Pathol 2022 03;32(2):e13015

Institute of Neuroscience and Medicine (INM-3, -4), Research Center Juelich, Juelich, Germany.

Anatomical cross-sectional imaging methods such as contrast-enhanced MRI and CT are the standard for the delineation, treatment planning, and follow-up of patients with meningioma. Besides, advanced neuroimaging is increasingly used to non-invasively provide detailed insights into the molecular and metabolic features of meningiomas. These techniques are usually based on MRI, e.g., perfusion-weighted imaging, diffusion-weighted imaging, MR spectroscopy, and positron emission tomography. Furthermore, artificial intelligence methods such as radiomics offer the potential to extract quantitative imaging features from routinely acquired anatomical MRI and CT scans and advanced imaging techniques. This allows the linking of imaging phenotypes to meningioma characteristics, e.g., the molecular-genetic profile. Here, we review several diagnostic applications and future directions of these advanced neuroimaging techniques, including radiomics in preclinical models and patients with meningioma.
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http://dx.doi.org/10.1111/bpa.13015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8877736PMC
March 2022

Combined TMS-fMRI Reveals Behavior-Dependent Network Effects of Right Temporoparietal Junction Neurostimulation in an Attentional Belief Updating Task.

Cereb Cortex 2022 Jan 28. Epub 2022 Jan 28.

Updating beliefs after unexpected events is fundamental for an optimal adaptation to the environment. Previous findings suggested a causal involvement of the right temporoparietal junction (rTPJ) in belief updating in an attention task. We combined offline continuous theta-burst stimulation (cTBS) over rTPJ with functional magnetic resonance imaging (fMRI) to investigate local and remote stimulation effects within the attention and salience networks. In a sham-controlled, within-subject crossover design, 25 participants performed an attentional cueing task during fMRI with true or false information about cue predictability. By estimating learning rates from response times, we characterized participants' belief updating. Model-derived cue predictability entered the fMRI analysis as a parametric regressor to identify the neural correlates of updating. rTPJ-cTBS effects showed high interindividual variability. The expected learning rate reduction with false cue predictability information by cTBS was only observed in participants showing higher updating in false than in true blocks after sham. cTBS modulated the neural signatures of belief updating, both in rTPJ and in nodes of the attention and salience networks. The interindividual variability of the behavioral cTBS effect was related to differential activity and rTPJ connectivity of the right anterior insula. These results demonstrate a crucial interaction between ventral attention and salience networks for belief updating.
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http://dx.doi.org/10.1093/cercor/bhab511DOI Listing
January 2022

Communication, Coordination, and Security for People with Multiple Sclerosis (COCOS-MS): a randomised phase II clinical trial protocol.

BMJ Open 2022 Jan 25;12(1):e049300. Epub 2022 Jan 25.

Department of Neurology, University of Cologne, Cologne, Nordrhein-Westfalen, Germany.

Introduction: Patients with multiple sclerosis (MS) have complex needs that range from organising one's everyday life to measures of disease-specific therapy monitoring to palliative care. Patients with MS are likely to depend on multiple healthcare providers and various authorities, which are often difficult to coordinate. Thus, they will probably benefit from comprehensive cross-sectoral coordination of services provided by care and case management (CCM). Though studies have shown that case management improves quality of life (QoL), functional status and reduces service use, such benefits have not yet been investigated in severely affected patients with MS. In this explorative phase ll clinical trial, we evaluated a CCM with long-term, cross-sectoral and outreaching services and, in addition, considered the unit of care (patients and caregivers).

Methods And Analysis: Eighty patients with MS and their caregivers will be randomly assigned to either the control (standard care) or the intervention group (standard care plus CCM (for 12 months)). Regular data assessments will be done at baseline and then at 3-month intervals. As primary outcome, we will evaluate patients' QoL. Secondary outcomes are patients' treatment-related risk perception, palliative care needs, anxiety/depression, use of healthcare services, caregivers' burden and QoL, meeting patients' and caregivers' needs, and evaluating the CCM intervention. We will also evaluate CCM through individual interviews and focus groups. The sample size calculation is based on a standardised effect of 0.5, and one baseline and four follow-up assessments (with correlation 0.5). Linear mixed models for repeated measures will be applied to analyse changes in quantitative outcomes over time. Multiple imputation approaches are taken to assess the robustness of the results. The explorative approach (phase ll clinical trial) with embedded qualitative research will allow for the development of a final design for a confirmative phase lll trial.

Ethics And Dissemination: The trial will be conducted under the Declaration of Helsinki and has been approved by the Ethics Commission of Cologne University's Faculty of Medicine. Trial results will be published in an open-access scientific journal and presented at conferences.

Trial Registration Number: German Register for Clinical Studies (DRKS) (DRKS00022771).
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http://dx.doi.org/10.1136/bmjopen-2021-049300DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8796263PMC
January 2022

Age and Anterior Basal Forebrain Volume Predict the Cholinergic Deficit in Patients with Mild Cognitive Impairment due to Alzheimer's Disease.

J Alzheimers Dis 2022 ;86(1):425-440

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany.

Background: Early and severe neuronal loss in the cholinergic basal forebrain is observed in Alzheimer's disease (AD). To date, cholinomimetics play a central role in the symptomatic treatment of AD dementia. Although basic research indicates that a cholinergic deficit is present in AD before dementia, the efficacy of cholinomimetics in mild cognitive impairment (MCI) remains controversial. Predictors of cholinergic impairment could guide individualized therapy.

Objective: To investigate if the extent of the cholinergic deficit, measured using positron emission tomography (PET) and the tracer 11C-N-methyl-4-piperidyl acetate (MP4A), could be predicted from the volume of cholinergic basal forebrain nuclei in non-demented AD patients.

Methods: Seventeen patients with a high likelihood of MCI due to AD and 18 age-matched cognitively healthy adults underwent MRI-scanning. Basal forebrain volume was assessed using voxel-based morphometry and a cytoarchitectonic atlas of cholinergic nuclei. Cortical acetylcholinesterase (AChE) activity was measured using MP4A-PET.

Results: Cortical AChE activity and nucleus basalis of Meynert (Ch4 area) volume were significantly decreased in MCI. The extent of the cholinergic deficit varied considerably across patients. Greater volumes of anterior basal forebrain nuclei (Ch1/2 area) and younger age (Spearman's rho (17)  = -0.596, 95% -CI [-0.905, -0.119] and 0.593, 95% -CI [0.092, 0.863])) were associated with a greater cholinergic deficit.

Conclusion: Data suggest that less atrophy of the Ch1/2 area and younger age are associated with a more significant cholinergic deficit in MCI due to AD. Further investigations are warranted to determine if the individual response to cholinomimetics can be inferred from these measures.
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http://dx.doi.org/10.3233/JAD-210261DOI Listing
April 2022

Information Exchange between Cortical Areas: The Visual System as a Model.

Neuroscientist 2022 Jan 20:10738584211069061. Epub 2022 Jan 20.

Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany.

As nearly all brain functions, perception, motion, and higher-order cognitive functions require coordinated neural information processing within distributed cortical networks. Over the past decades, new theories and techniques emerged that advanced our understanding of how information is transferred between cortical areas. This review surveys critical aspects of interareal information exchange. We begin by examining the brain's structural connectivity, which provides the basic framework for interareal communication. We then illustrate information exchange between cortical areas using the visual system as an example. Next, well-studied and newly proposed theories that may underlie principles of neural communication are reviewed, highlighting recent work that offers new perspectives on interareal information exchange. We finally discuss open questions in the study of the neural mechanisms underlying interareal information exchange.
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http://dx.doi.org/10.1177/10738584211069061DOI Listing
January 2022
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