Electrophysiology is a key technique in our lab. We use it to get a picture of the instantaneous network activity by monitoring the activity of large set of neurons. We use tetrodes and silicon probes in rats and mice. Much of what we do makes use of tools from the Open Ephys project (to which goes our gratitude). With the NeuroSeeker collaboration we helping creating some of the highest density probes for neural recording in existence, currently in use in our lab
For longer term exploration of memory circuits we are now using calcium microendoscopy, with initial funding by the Inscopix DECODE award. Current work includes application of this methodology to the study of memory accumulation in the object-space task. We are working at the combination of this technique with electrophysiology
We created a mouse head-fixed virtual reality setup, current in use for working memory and long-term memory experiments with advanced silicon probes. Future uses of the set will include optical imaging in different modalities.
One of our main focuses is the development of tasks that enable us to track memories over time and changing situations, while being compatible with electrophysiological and optical investigation of neural circuits. A first result of our collaboration is the Object-Space task (Genzel et al. bioaRxiv), for rats and mice, which addresses the accumulation of evidence across multiple, non-identical episodes. The task is currently in use in many preparations in our lab.
Sleep is a key topic for our lab. A few years ago, we contributed initial evidence for the interaction between hippocampus and prefrontal cortex during sleep (Battaglia et al. 2004, Peyrache et al. 2009, Peyrache et al. 2011, Genzel et al. 2017). We also found that the same hippocampal-PFC axis is involved in the observed decrease of sleep effect on memory in depression and schizophrenia (Genzel et al. 2015).
We continue to study the interaction between sleep, memory and behavior and neural dynamics during sleep (reviews Navarro Lobato, Genzel 2018, Genzel, Kroes, Dresler, Battaglia 2014, Genzel 2015). Further, in collaboration with Judith Homberg and Nael Nadif Kasri we are investiagting these same questions in animal models of disease.
In humans, we use functional MR Imaging as well as sleep-EEG recordings to investigate how sleep impacts on changes of activity in memory-related brain networks from encoding to retrieval. We have previously shown that in patients with depression and schizophrenia decreased hippocampal-prefrontal cortex connectivity during learning predicts sleep related memory deficits (Genzel et al. 2015).
Here at the Donders Institute we continue our investigations in healthy controls, with behavioural paradigms matching our rodent approaches.
Our lab is a funding member of the Translational Neuroscience Unit of the Donders Institute and the RadboudUMC. It is a collaborative environment where lab facilities and expertise are shared across multiple labs. This movie, that sees Lisa Genzel as one of the authors, gives a feel for this