ETD

• gamma
• mouse model
• optogenetic
• oscillations
• parvalbumine positive interneurons
• robotic rehabilitation
• stroke

This work focalizes on the study of the GABAergic parvalbumin positive interneurons (PV+) in a mouse model of motor cortical stroke. First, I investigated the connectivity of PV+ interneurons through a specific labelling of the efferent cells using an EnvA pseudotyped Rabies virus (RV) in collaboration with Prof. Pasqualetti and his group of the Department of Biology. Mice expressing Cre recombinase in PV+ (PV::Cre) has been injected in Rostral Forelimb Area, premotor cortex with an adeno-associated virus expressing the TVA receptor for RV. After two weeks the RV has been injected in the same site. With this approach it has been possible to carry out a monosynaptic tracing of the PV+ afferences. I then quantified the PV+ target cells and the only RV expressing cells with immunohistochemistry. I found retrogradely labelled neurons in ipsilesional cortex and thalamus in healthy animals and started to study the differences between sham and ictus mice was done.
A second experiment had evaluated the effects of the PV+ optogenetic stimulation associated with robotic rehabilitation. With this system, I was able to use intrinsic properties of PV+ to synchronise brain oscillations in gamma frequencies as a neuromodulatory treatment to couple with robotic rehabilitation. In PV::Cre transgenic animals injected with ChR2 virus the activation is restricted to PV+ interneurons allowing to deepen their role in the rehabilitation process. This experiment focuses on the effects of the gamma band synchronization induced by the PV+ stimulation.