Liset M de la Prida is a Physicist (1994) and PhD in Neuroscience (1998), who leads the Laboratorio de Circuitos Neuronales at the Instituto Cajal, Madrid, Spain (http://www.hippo-circuitlab.es). The main focus of her lab is to understand the function of the hippocampal circuits in the normal and the diseased brain, in particular oscillations and neuronal representations. She is a leading international expert in the study of the basic mechanisms of physiological ripples and epileptic fast ripples, with strong visibility as developer of novel groundbreaking electrophysiological tools. Dr. de la Prida serves as an Editor for prestigious journals including eLife, Journal of Neuroscience Methods and eNeuro, and has commissioning duties in the American Epilepsy Society, FENS and the Spanish Society for Neurosciences.

Accumulating data indicate that the brain can affect immunity, as evidenced, for example, by the effects of stress, stroke, and reward system activity on the peripheral immune system. However, our understanding of this neuroimmune interaction is still limited. Importantly, we do not know how the brain evaluates and represents the state of the immune system. In this talk, I will present our latest study from our lab, designed to test the existence of immune-related information in the brain and determine its relevance to immune regulation. We hypothesized that the InsCtx, specifically the posterior InsCtx (as a primary cortical site of interoception in the brain), is especially suited to contain such a representation of the immune system. Using activity-dependent cell labeling in mice (FosTRAP), we captured neuronal ensembles in the InsCtx that were active under two different inflammatory conditions (dextran sulfate sodium [DSS]-induced colitis and zymosan-induced peritonitis). Chemogenetic reactivation of these neuronal ensembles was sufficient to broadly retrieve the inflammatory state under which these neurons were captured. Moreover, using retrograde neuronal tracing, we found an anatomical efferent pathway linking these InsCtx neurons to the inflamed peripheral sites. Taken together, we show that the brain can store and retrieve specific immune responses, extending the classical concept of immunological memory to neuronal representations of inflammatory information.

This talk will focus on the importance of using natural behaviors in neuroscience research – the “Natural Neuroscience” approach. I will illustrate this point by describing studies of neural codes for spatial behaviors and social behaviors, in flying bats – using wireless neurophysiology methods that we developed – and will highlight new neuronal representations that we discovered in animals navigating through 3D spaces, or in very large-scale environments, or engaged in social interactions. In particular, I will discuss: (1) A multi-scale neural code for very large environments, which we discovered in bats flying in a 200-meter long tunnel. This new type of neural code is fundamentally different from spatial codes reported in small environments – and we show theoretically that it is superior for representing very large spaces. (2) Rapid modulation of position × distance coding in the hippocampus during collision-avoidance behavior between two flying bats. This result provides a dramatic illustration of the extreme dynamism of the neural code. (3) Local-but-not-global order in 3D grid cells – a surprising experimental finding, which can be explained by a simple physics-inspired model, which successfully describes both 3D and 2D grids. These results strongly argue against many of the classical, geometrically-based models of grid cells. (4) I will also briefly describe new results on the social representation of other individuals in the hippocampus, in a highly social multi-animal setting. The lecture will propose that neuroscience experiments – in bats, rodents, monkeys or humans – should be conducted under evermore naturalistic conditions.