Gedächtnis und Navigation - N. Axmacher

Gedächtnis und Navigation

N. Axmacher
Cognitive neuroscience of human memory and spatial navigationHuman invasive electrophysiologyLaminar neuroimaging
Gruppenbanner - N. Axmacher

(deu, translate me)The overarching goal of my research at ELH is to use 7T fMRI to understand the laminar profile of memory and spatial navigation. More specifically, we apply multivariate analysis methods (representational similarity analysis in combination with deep neural networks) to identify stimulus-specific memory traces during perception of natural stimuli and track their representational format and transformation during subsequent memory stages including short-term memory maintenance, long-term memory consolidation, and episodic memory retrieval. Laminar recordings are of particular interest to investigate the role of feedforward and feedback projections between neocortical regions and between the neocortex and the hippocampus. In addition, we capitalize on ecologically valid paradigms including movies and interactive VR tasks to study the effect of emotions, stress, and trauma-analogue experiences on intrusive memories as a model of PTSD. Related to spatial navigation, we investigate the neural mechanisms, functional role, and pathological relevance of grid cell-like representations, a putative neural network marker of grid cell functionality in the entorhinal cortex and beyond. Grid cells and grid cell-like representations are particularly relevant for path integration, but may also play a role for visual processing of natural scenes and concept processing. Laminar recordings allow disentangling several competing hypotheses of the generation of grid cell-like representations. In addition, we study the interaction between different navigational systems including entorhinal cortex, hippocampus, and retrosplenial cortex.

Aktuelle Projekte
  • DFG: SFB 1280 "Extinction Learning" 2021 - 2025, Project number 316803389, PI of the research projects A02 "Neural mechanisms of context generalization", A03 "Functional role and dynamic change of extinction network connectivity" and F02 "Focus Group Neuroimaging and Genetics"
  • MERCUR: "Unlocking the function of the hippocampus with laminar fMRI" 2022 - 2024
Ausgewählte Publikationen
  • Oever ST, AT Sack, CR Oehrn, et al., An engram of intentionally forgotten information., Nat Commun (2021)
  • Bierbrauer A, M Fellner, R Heinen, et al., The memory trace of a stressful episode., Curr Biol (2021)
  • Bierbrauer A, L Kunz, CA Gomes, et al., Unmasking selective path integration deficits in Alzheimer's disease risk carriers., Sci Adv (2020)
  • Lee H, R Stirnberg, S Wu, et al., Genetic Alzheimer's Disease Risk Affects the Neural Mechanisms of Pattern Separation in Hippocampal Subfields., Curr Biol (2020)
  • Kunz L, L Wang, D Lachner-Piza, et al., Hippocampal theta phases organize the reactivation of large-scale electrophysiological representations during goal-directed navigation., Sci Adv (2019)
  • Zhang H, J Fell, N Axmacher, Electrophysiological mechanisms of human memory consolidation., Nat Commun (2018)
  • Kunz L, TN Schröder, H Lee, et al., Reduced grid-cell-like representations in adults at genetic risk for Alzheimer's disease., Science (2015)
  • Fell J, N Axmacher, The role of phase synchronization in memory processes., Nat Rev Neurosci (2011)
  • Axmacher N, MX Cohen, J Fell, et al., Intracranial EEG correlates of expectancy and memory formation in the human hippocampus and nucleus accumbens., Neuron (2010)
  • Axmacher N, MM Henseler, O Jensen, et al., Cross-frequency coupling supports multi-item working memory in the human hippocampus., Proc Natl Acad Sci U S A (2010)