Lisa Genzel | ''Sleep for Systems Consolidation''
Abstract: Sleep is important for memory consolidation. More specifically, it is thought that during sleep recent memories are replayed in the hippocampus and prefrontal cortex to allow for abstraction of salient information across events and consolidation from the initial, hippocampal storage to the long-term representation in the cortex. In this talk data from both humans and rats will be presented, providing evidence for this process.
Francesco Battaglia | Finding cell assemblies in brain activity
Abstract: The brain encodes information in the activity of “cell assemblies”, groups of neurons that are tied together by synaptic plasticity and are likely to activate in a synchronous way. In turn, cell assemblies activate in sequences, reflecting the temporal ordering of the events forming e.g. the memory of an episode. Spontaneous activity (taking place as the subject is inactive) is highly structured, and contains the activation of many cell assemblies, which may reflect stored memories, imagery, or planning of future actions. I present two methods for finding cell assemblies: In the first, we reconstruct the “functional connectivity matrix” by mapping recorded neural data on an a spin-glass network, and infer the maximum entropy model, in what is known as “reverse Ising inference”. From the connectivity matrix, cell assemblies can be reconstructed and their activity analyzed.
The second method tackles directly the temporal dimension by defining a distance between spike patterns inspired to the Earth Mover’s distance from Optimal Transportation theory, and then applying density-based clustering on the resulting distance matrix. Application of the method to simulated and real data reconstructs the structure of data and of the behavioral circumstances the animal experiences, in a completely unsupervised fashion.
I will frame these method in the context of systems neuroscience research, with particular focus on the study of memory system'
Find some information about their work: http://www.memorydynamics.org/