abstract Christian Doeller

Christian Doeller (Donders Institute for Brain, Cognition and Behaviour Radboud University Nijmegen, The Netherlands)

From cells to systems: grids, boundaries and theta in spatial cognition

There has been considerable progress in identifying the specific characteristics of neural representations of space in rodents, however their exact contribution to memory remains unknown. In my talk I will present results of experiments in which we combine functional neuroimaging with virtual reality techniques in humans. With fMRI we find evidence for spatial representations in human entorhinal cortex and hippocampus consistent with the firing of entorhinal grid cells and hippocampal place cells in rodents. Grid-cell like representations further support spatial memory and are also found in a circuit of regions which markedly overlaps the network for episodic memory. In addition, we observe that hippocampal learning occurs independent of reinforcement, a finding which is inconsistent with assumptions of modern learning theory. With MEG we show a link between the traditional role of movement-related theta oscillations in rodents and mnemonic processing-related theta in humans suggesting that hippocampal activity and theta related to volitional movement may facilitate self-directed learning. In sum, our approach might contribute to a more coherent understanding of brain function from neural representations to systems-level involvement in behaviour.