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In this work, we focus on the communication aspect of decentralized learning, which involves multiple agents training a shared machine learning model using decentralized stochastic gradient descent (D-SGD) over distributed data. In particular, we investigate the impact of broadcast transmission and probabilistic random access policy on the convergence performance of D-SGD, considering the broadcast nature of wireless channels and the link dynamics in the communication topology. Our results demonstrate that optimizing the access probability to maximize the expected number of successful links is a highly effective strategy for accelerating the system convergence., Comment: 5 pages, 5 figures, accepted in IEEE SPAWC 2023

Analyses of MRI-indexed substantia nigra and locus coeruleus integrity in participants of the Berlin Aging Study-II (study website: https://www.base2.mpg.de/en)

Authors: Martin J. Dahl* 1,2, Mara Mather 2, Markus Werkle-Bergner 1, Briana L. Kennedy 2,3, Samuel Guzman 4, Kyle Hurth4, Carol A. Miller 4, Yuchuan Qiao 5, Yonggang Shi5, Helena C. Chui 6, & John M. Ringman 6 Affiliations: 1 Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany 2 Davis School of Gerontology, University of Southern California, 90089 Los Angeles, CA, USA 3 School of Psychological Science, University of Western Australia, Perth, Australia 4 Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA 5 Laboratory of Neuro Imaging (LONI), USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA 6 Department of Neurology, Keck School of Medicine, University of Southern California, 90033 Los Angeles, CA, USA * Corresponding author: MJD (dahl [at] mpib-berlin.mpg.de) We aimed at improving the reliability and validity of MR-based locus coeruleus detection. Leveraging a meta-analytical approach, we aggregated across previously published maps of the locus coeruleus (Betts et al., 2017; Dahl et al., 2019; Keren et al., 2009; Liu et al., 2019; Tona et al., 2017; Ye et al., 2020) to derive a biologically plausible volume of interest (meta mask) that shows high agreement across investigations. We freely share the locus coeruleus meta mask with the scientific community. For a description of the methods, please see: https://doi.org/10.1101/2020.11.16.20232561

Code and data for the article titled "Noradrenergic responsiveness supports selective attention across the adult lifespan" Journal of Neuroscience 27 May 2020, 40 (22) 4372-4390; DOI: https://doi.org/10.1523/JNEUROSCI.0398-19.2020 (Preprint: https://www.biorxiv.org/content/10.1101/551879v2) Authors: Martin J. Dahl[1], Mara Mather[2], Myriam C. Sander[1], & Markus Werkle-Bergner[1] Affiliations: [1] Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany [2] Davis School of Gerontology, University of Southern California, 90089 Los Angeles, USA

Systems based on the Robot Operating System (ROS) are easy to extend with new on-line algorithms and devices. However, there is relatively little support for coordinating a large number of heterogeneous sub-systems. In this paper we propose an architecture to model and control collaborative and intelligent automation systems in a hierarchical fashion., Comment: Submitted to IROS 2019. \c{opyright} 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses

Pathological alterations to the locus coeruleus, the major source of noradrenaline in the brain, are histologically evident in early stages of neurodegenerative diseases. Novel MRI approaches now provide an opportunity to quantify structural features of the locus coeruleus in vivo during disease progression. In combination with neuropathological biomarkers, in vivo locus coeruleus imaging could help to understand the contribution of locus coeruleus neurodegeneration to clinical and pathological manifestations in Alzheimer's disease, atypical neurodegenerative dementias and Parkinson's disease. Moreover, as the functional sensitivity of the noradrenergic system is likely to change with disease progression, in vivo measures of locus coeruleus integrity could provide new pathophysiological insights into cognitive and behavioural symptoms. Locus coeruleus imaging also holds the promise to stratify patients into clinical trials according to noradrenergic dysfunction. In this article, we present a consensus on how non-invasive in vivo assessment of locus coeruleus integrity can be used for clinical research in neurodegenerative diseases. We outline the next steps for in vivo, post-mortem and clinical studies that can lay the groundwork to evaluate the potential of locus coeruleus imaging as a biomarker for neurodegenerative diseases.