Desdemona Fricker Dr at INCC (Integrative Neuroscience and Cognition Center)- UMR8002, Team co-leader of Spacial Orientation TeamDesdemona FrickerDr at INCC (Integrative Neuroscience and Cognition Center)- UMR8002, Team co-leader of Spacial Orientation Team
Cellular and circuit underpinnings of head direction signals, by Desdemona Fricker
Summary: Cellular and circuit underpinnings of head direction signals
Orientation in space is a fundamental cognitive process relying on brain-wide neuronal circuits. Hippocampus is particularly important for the encoding of space, in rodents as well as in humans. The presubiculum, in the parahippocampal region, is at the center of the brain’s head direction system, it is upstream of place and grid cells, and more closely linked to sensory inputs. My team has provided the first full description of cell types, currents and the layer organization of the presubiculum. In this seminar, I will focus on the afferent and efferent cell-type specific connectivity of the presubiculum. While the presubicular head-direction signal depends on synaptic input from the anterior thalamus, the intra- and interlaminar information flow in the microcircuit may contribute to refine directional tuning. I will present our recent results using independent double wavelength optogenetics, showing that thalamic and retrosplenial inputs converge onto layer 3 presubicular neurons. I will discuss how the non-linear summation of these inputs may be important for plasticity and for visual landmark updating of head direction signals.
Desdemona Fricker studied Medicine at the University of Tübingen (Germany). She was initiated to Neurobiology research during a one-year internship in Philippe Ascher’s lab at the Ecole Normale Supérieure in Paris. After her MD, she enrolled in a Master degree for Pharmacology at the Sorbonne University in Paris, and conducted a PhD thesis on Factors controlling excitability in the Hippocampus, at the Pasteur Institute, under the supervision of Richard Miles. She trained as a Postdoc at Baylor College of Medicine in Houston, Texas, in the lab of Daniel Johnston, studying dendritic currents and long-term plasticity. Shethen joined the CNRS in 2002, to work at the Paris Brain Institute, at the Pitié–Salpêtrière Hospital. In 2016, she moved to the Integrative Neuroscience and Cognition Center at the Université de Paris, where she is now a Director of Research. Her research interests focus on the cellular mechanisms underlying head direction coding and, more generally, the neural basis of multisensory integration and spatial orientation.