Project B2: Changes in large-scale interactions as a mechanism of adaptive plasticity
Prof. Dr. Brigitte Röder
Biopsychology and Neuropsychology, University of Hamburg
Prof. Dr. Andreas Engel
Dept. of Neurophysiology and Pathophysiology, UKE
Sensory deprivation is accompanied by a crossmodal activation of deprived sensory brain regions. For ex-ample, in the blind occipital cortical activity has been suggested to result in compensatory performance changes. This project uses an extensive training paradigm with different types of stimuli. It is hypothesized that blind individuals reach a higher asymptotic performance level than sighted controls which in turn is re-lated to a training induced integration of parts of occipital cortex into the processing network seen in sighted controls. Thus, this project tests whether extensive changes in cortico-cortical interactions rather than a com-pensatory allocation of functions to individual deprived brain areas is the critical mechanism of crossmodal plasticity.
Project B3: Network mechanisms underlying information transfer in the entorhinal cortex-hippocampus circuitry during learning and memory
Dr. Fabio Morellini
Heisenberg Group, ZMNH, UKE
Prof. Dr. Dirk Isbrandt
Heisenberg Group, ZMNH, UKE
The project is designed to investigate the neuronal activities and multi-site connectivity in entorhinal cortex and hippocampus that control information transfer between these regions. To this aim, we will analyze the physiological and behavioral consequences caused by the alteration of intrinsic resonance properties of neu-rons. Specifically, we will analyze how transgenic inhibition of Kv7/M and HCN/h currents in specific neu-ronal populations in mice affects extracellular current oscillations and unit activity in the entorhinal cortex and hippocampus at different stages of learning and memory consolidation and retrieval.
Project B4: Dependence of memory consolidation on synaptic consolidation in the cortico-hippocampal network
Prof. Dr. Dietmar Kuhl
Dept. of Molecular and Cellular Cognition, ZMNH, UKE
This project aims at investigating the synaptic multi-site interactions between the hippocampus and the neo-cortex throughout the process of memory consolidation. So far it is not known if cortical and hippocampal synaptic plasticity consolidates in a similar or dissimilar manner and if continuous re-consolidation in the hippocampus is essential for long-term memory even when cortical representations already exist. Moreover, nothing is known about the underlying molecular and cellular mechanisms. The basis for the project is the finding that the activity-regulated gene Arc/Arg3.1 is essential for the consolidation of long-term synaptic plasticity and remote memory. In genetically engineered mice we will restrict deletion of Arc/Arg3.1 either to the hippocampus or to the cortex, and will employ behavioural tests to assess the development of remote memory. Electrophysiological recordings will be conducted in vivo and in vitro to measure changes in synap-tic transmission within the cortico-hippocampal circuitry.
Project B6: Emergence and plasticity of architectures underlying multi-site communication
Prof. Dr. Peter König
Institute of Cognitive Science, University of Osnabrück
This project investigates mechanisms of integration and segregation of multimodal sensory and sensorimotor events. We use unsupervised learning to optimize properties of static representations of audio-visual stimuli captured in different reference frames. Next, interactions on slow, medium and fast time scales are included within a unified formalism. We generalize these results to structured hierarchical networks modelled accord-ing to the statistical constraints of the cortical connectome. Finally, we apply these results to learning and plasticity after focal cortical lesions. This project directly relates to several other projects of this SFB pro-posal and links descriptive and mechanistic levels and thereby contributes to our understanding of cortical function.