Lecture: Christian Doeller
Cellular cognition: From spatial coding to mnemonic networks
Dr. Christian Doeller
Donders Institute for Brain, Cognition and Behaviour, Radboud Universit, Nijmegen, The Netherlands
The hippocampal formation has been associated with a wide variety of functions including spatial navigation, memory encoding and retrieval, relational processing, novelty detection, and imagination. These functions are dissimilar in terms of their behavioural consequences and modality of representation. Consequently, theoretical standpoints have focused on explaining the role of the hippocampal formation in terms of either its spatial or non-spatial functions. Contrary to this dichotomy, we propose that it is essential to look beyond these traditional boundaries between mnemonic and spatial functions, and focus instead on the processes that these functions have in common. In my talk I will present results of experiments in which we combine functional neuroimaging with virtual reality techniques in humans. Using fMRI proxy-measures of cellular activity we find evidence for spatial representations in human entorhinal cortex and hippocampus consistent with the firing of spatially tuned neurons in rodents. These representations support memory formation and are also found in a circuit of regions which markedly overlaps the network for episodic memory. 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.
Host: Henrik Ehrsson