ASTRONET · Computational approaches to reveal the role of astrocytes in information processing and neural networks dynamics

Information about the external world is encoded in the brain through the dynamical activity of neuronal ensembles, so-called neural population codes. Neurons, however, are not the only cell types making up the nervous tissue. Astrocytes interact with neurons at the synaptic and network level. Astrocytic intracellular calcium dynamics integrates and modulates surrounding neural activity over a wide range of spatial and temporal scales. Recent studies showed that these calcium transients encode information about external stimuli, and that this information is complementary to that encoded in neural activity, suggesting that astrocytes may play an active role in computations carried out in neural circuits. Here, I will investigate the role of astrocytes in shaping neural population, focusing on representations of space in the mouse the hippocampus during navigation. By using biophysically plausible network modeling and information theory I will characterize how the dynamics and information coding properties of networks of neurons are enhanced when they interact with astrocytes. The model will be constrained and guided by analysis of simultaneous dual-imaging recordings of neurons and astrocytes. Then I will consider new data, provided by the secondment lab, of longitudinal neural recordings during which astrocytic calcium dynamics was chemogenetically manipulated during the exploration of familiar and new environments over days. I will determine the causal role of astrocytes in neural information processing by using information theory and machine learning to analyze neural information coding when astrocytes are or are not perturbed. Then, I will use the data to construct biophysically plausible models of astrocytes contribute to the evolution of neural codes across days. These major advances in modelling and understanding how astrocytes support an complement neural networks will contribute to understanding how glial cells contribute to healthy brain function.