A01 A02 A03 A04 A05 A07 A09 A10 A11 A12 A13 A14 A18 A19 A21 F01 F02

A02 – Neural mechanisms of context generalization

Nikolai Axmacher

While extinction is context-dependent, acquisition contexts generalize easily. Here, we investigate how context generalization is controlled by neural activity in core regions of the extinction network. The generalization and distinctiveness of neural context representations will be assessed via multivariate analysis methods. Combining simultaneous EEG/fMRI recordings in healthy participants with intracranial EEG and single-unit recordings in epilepsy patients, we will identify the neural mechanisms that control if contexts generalize or stay distinct, and if renewal or extinction retrieval occurs. Our data will provide a unique bridge between human neuroimaging and animal electrophysiology studies of extinction learning.

Guiding questions of A02:

  • How are specific contexts represented in the human brain across several levels of brain organization?
  • How do the neural representations of contexts change during initial acquisition and extinction learning?
  • Is the generalization or distinctiveness of context representations during acquisition and extinction predictive of renewal or extinction retrieval?
  • Which neural mechanisms support these representational changes?

Nikolai Axmacher

Projektleiter A02, A03, F02

Ruhr-Universität Bochum

Antoine Bouillant

Postdoc A02

Ruhr-Universität Bochum

Rebekka Heinen

Doktorandin A02

Ruhr-Universität Bochum

10 project-relevant publications

Axmacher N, Cohen MX, Fell J, Haupt S, Dumpelmann M, Elger CE, Schlaepfer TE, Lenartz D, Sturm V, Ranganath C (2010) Intracranial EEG correlates of expectancy and memory formation in the human hippocampus and nucleus accumbens. Neuron. 65(4): 541–549.

Axmacher N, Elger CE, Fell J (2008) Ripples in the medial temporal lobe are relevant for human memory consolidation. Brain. 131(Pt 7): 1806–1817.

Axmacher N, Henseler MM, Jensen O, Weinreich I, Elger CE, Fell J (2010) Cross-frequency coupling supports multiitem working memory in the human hippocampus. Proc Natl Acad Sci USA. 107(7): 3228–3233.

Deuker L, Olligs J, Fell J, Kranz TA, Mormann F, Montag C, Reuter M, Elger CE, Axmacher N (2013) Memory consolidation by replay of stimulus-specific neural activity. J Neurosci. 33(49): 19373–19383.

Fell J, Axmacher N (2011) The role of phase synchronization in memory processes. Nat Rev Neurosci. 12(2): 105–118.

Kunz L, Schroder TN, Lee H, Montag C, Lachmann B, Sariyska R, Reuter M, Stirnberg R, Stocker T, Messing-Floeter PC, Fell J, Doeller CF, Axmacher N (2015) Reduced grid-cell-like representations in adults at genetic risk for Alzheimer’s disease. Science. 350(6259): 430–433.

Staresina BP, Bergmann TO, Bonnefond M, van der Meij R, Jensen O, Deuker L, Elger CE, Axmacher N, Fell J (2015) Hierarchical nesting of slow oscillations, spindles and ripples in the human hippocampus during sleep. NatNeurosci. 18(11): 1679–1686.

Staresina BP, Fell J, Do Lam ATA, Axmacher N, Henson RN (2012) Memory signals are temporally dissociated in and across human hippocampus and perirhinal cortex. Nat Neurosci. 15(8): 1167–1173.

Watrous AJ, Deuker L, Fell J, Axmacher N (2015) Phase-amplitude coupling supports phase coding in human ECoG. Elife. 4.

Zhang H, Fell J, Staresina BP, Weber B, Elger CE, Axmacher N (2015) Gamma power reductions accompany stimulusspecific representations of dynamic events. Curr Biol. 25(5): 635–640. 73