High-Resolution fMRI of the Human Medial Temporal Lobe
I’m interested in the functional architecture of the human medial temporal lobe. Thus, I investigate which brain regions and networks are involved in specific memory processes. For example, how our brain can manage to separate very similar experiences without confusing them in memory. On the other hand, brain systems are differentially involved in the processing of different stimulus material – such as objects and scenes. Memory for objects and scenes partly relies on different networks in the medial temporal lobe. In order to be able to investigate those networks and processes in detail, I use high-resolution functional MRI at 7T to analyze the differential involvement as well as the differential connectivity profile of memory related subregions in young and healthy adults. I believe that high-resolution fMRI at 7 Tesla will also have a big impact on research in ageing and neurodegenerative diseases. Therefore, I’m part of the European Ultrahigh-Field Imaging Network for Neurodegenerative Diseases (EUFIND) where we explore the potential of Ultrahigh-field MRI methods for research in neurodegenerative diseases.
Berron et al. 2016. Strong Evidence for Pattern Separation in Human Dentate Gyrus. The Journal of Neuroscience.
Maass*, Berron* et al. 2015. Functional subdivisions of the human entorhinal cortex. eLife.
Koster, R., Chadwick, MJ., Chen, Y., Berron, D., Banino, A., Düzel, E., Hassabis, D., Kumaran, D. 2018. Big-loop recurrence within the hippocampal system supports integration of information across episodes. Neuron.
Grande X, Berron D, Horner AJ, Bisby JA, Düzel E, Burgess N. 2019. Holistic recollection via pattern completion involves hippocampal subfield CA3. The Journal of Neuroscience.
Object and Scene Memory in Ageing and Early Alzheimer’s Disease
In the medial temporal lobe there are domain-specific pathways that support different types of memory. While the perirhinal cortex and the anterolateral entorhinal cortex are more involved in memory for objects, the parahippocampal cortex and the posterior-medial entorhinal cortex are preferentially associated with memory for spatial scenes. The same is true for cortical regions in the anterior-temporal and the posterior medial system, respectively. Interestingly, these networks overlap with Alzheimer’s pathology in different disease stages. Thus, I use fMRI in combination with behavioral testing and PET as well as CSF biomarkers in my research to further our understanding of early impairment of cognition and memory pathways.
Berron et al. 2018. Age-related functional changes in domain-specific medial temporal lobe pathways. Neurobiology of Aging.
Berron et al. 2019. Higher CSF tau levels are related to hippocampal hyperactivity and object mnemonic discrimination in older adults. The Journal of Neuroscience.
Manual Segmentation of Subregions in the Medial Temporal Lobe
Subregions in the medial temporal lobe are heavily involved in human episodic memory. Recent research showed that subregions are differentially involved in specific memory processes and functions. In order to assess structure-function relationships between the volume and thickness of MTL subregions on one side and specific memory functions on the other, but also to investigate their specific activity profile, it is necessary to have anatomical masks with regions of interest. Therefore, we developed a manual segmentation protocol for MTL subregions together with colleagues from the DZNE in Magdeburg and collaborators at the University of Pennsylvania and the Allen Institute for Brain Science in Seattle. However, in order to be able to better interpret research on MTL subregions across studies, I’m part of the Steering Committee of the Hippocampal Subfields Group to harmonize segmentation protocols across research labs.
Berron*, Vieweg* et al. 2017. A protocol for manual segmentation of medial temporal lobe subregions in 7Tesla MRI. Neuroimage Clinical.
De Flores R*, Berron D* et al. 2019. Characterization of hippocampal subfields using ex vivo MRI and histology data: lessons for in vivo segmentation. Hippocampus.
Wisse LEM, Daugherty AM, Olsen RK, Berron D et al. 2016. A harmonized segmentation protocol for hippocampal and parahippocampal subregions: Why do we need one and what are the key goals? Hippocampus.
Digital biomarkers to track vulnerable cognitive functions in preclinical Alzheimer’s disease
Much of my work focuses on memory functions that are early affected in the course of Alzheimer’s disease and I use brain imaging to develop memory tasks that specifically rely on brain regions that are early affected by Alzheimer’s disease pathology. On the other hand, memory performance shows quite some variability across individuals which makes it difficult to rely on a single test session. Thus, we have translated our memory tasks into smartphone-based assessments which allow for repeated, longitudinal testing of specific memory functions in a remote and unsupervised setting. Recent results from a Citizen Science project within Germany highlight the feasibility and potential of such approaches. Using these techniques, I investigate individual trajectories of memory decline in early stages of Alzheimer’s disease using biomarkers for AD pathology based on positron emission tomography (PET), cerebrospinal fluid (CSF) and blood plasma. Following my goal to translate our research findings into society, I have co-founded the university spin-off neotiv, where we develop a digital platform including a mobile app to bring remote, unsupervised cognitive testing into research and health care.
Berron, D. und Düzel, E.: “Digitales Monitoring von spezifischen kognitiven Beeinträchtigungen in der frühen Alzheimer-Erkrankung“; in Jessen, F., Bug, C. (Hrsg.): “Disease Interception”, eRelation Verlag, Bonn, 2019, S. 79-91 (in german language only, non peer-reviewed)
Düzel E, Thyrian JR, Berron D. 2019. Innovation in der Diagnostik – Mobile Technologien. Der Nervenarzt. (in german language only)