Prof. Dr. Benjamin Grewe

Embedding Associative Memories in Neuronal Networks of the Emotional Brain

The next presentation was given by Prof. Dr. Benjamin Grewe from the Institute of Neuroinformatics (ETH Zürich, Switzerland). He talked about "Embedding Associative Memories in Neuronal Networks of the Emotional Brain". Combining auditory fear conditioning, an established model of associative learning, with simultaneous recordings of the activity of 150 – 200 neurons in the amygdala of mice by means of a miniature, head-mounted fluorescence microscope, he gained new insights into the mechanism that links a conditioned stimulus (CS) to an unconditioned stimulus (US). In contrast to the widely-held view that the learned CS-US association results from a Hebbian, i.e. synaptic plasticity-dependent mechanism, he obtained evidence that fear learning coincides with a shift of the neuronal ensemble encoding CS towards the ensemble encoding US. Thus, the two neuronal populations encoding either CS or US, which were initially non-overlapping, became more congruent as the association between the stimuli was established.