Brain-wide microstrokes affect the stability of memory circuits in the hippocampus

Heiser, Hendrik; Kiessler, Filippo; Roggenbach, Adrian; Ibanez, Victor; Wieckhorst, Martin; Helmchen, Fritjof; Gjorgjieva, Julijana; Wahl, Anna-Sophia (2025): Brain-wide microstrokes affect the stability of memory circuits in the hippocampus. Nature Communications, 16 (3462). ISSN 2041-1723

Abstract

Cognitive deficits affect over 70% of stroke survivors, yet the mechanisms by which multiple small ischemic events contribute to cognitive decline remain poorly understood. In this study, we employed chronic two-photon calcium imaging to longitudinally track the fate of individual neurons in the hippocampus of mice navigating a virtual reality environment, both before and after inducing brain-wide microstrokes. Our findings reveal that, under normal conditions, hippocampal neurons exhibit varying degrees of stability in their spatial memory coding. However, microstrokes disrupted this functional network architecture, leading to cognitive impairments. Notably, the preservation of stable coding place cells, along with the stability, precision, and persistence of the hippocampal network, was strongly predictive of cognitive outcomes. Mice with more synchronously active place cells near important locations demonstrated recovery from cognitive impairment. This study uncovers critical cellular responses and network alterations following brain injury, providing a foundation for novel therapeutic strategies preventing cognitive decline.

• Doc-Type: Article (LMU Hospital)
• Organisational unit (Faculties): 07 Medicine > Medical Center of the University of Munich > Institute for Stroke and Dementia Research (ISD)
• DFG subject classification of scientific disciplines: Life sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 408885537
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892