Studying neuronal network and cellular level brain activity in animals that are behaving naturally is vital if we wish to understand the neural basis of complex behaviours. To achieve this neuroscientists employ in vivo electrophysiological techniques, which allow for the recording of emergent neuronal network oscillations and single unit activity. Until recently, the only feasible way of recording this activity in mice was to attach surgically implanted intracranial probes to physical wires. These physical wires produce shearing forces which ultimately impede movement and produce stress and discomfort in the animal. Recently, a lightweight, battery-powered wireless transmitter (TaiNi) has been developed for use in mice. By reducing stress and movement restriction associated with physical tethering, this technology represents a significant welfare refinement. In this project, we will transfer the skills and knowledge associated with using the TaiNi system from one of the co-developers (Eli Lilly) to two academic groups. We have designed a short project which will provide proof of principle that wireless technologies can supersede our current tethered systems.
In this project, we will examine the hypothesis that the retrosplenial cortex (RSC) provides associational information to the medial entorhinal cortex (MEC) in a contextual memory task. Using the TaiNi system, we will examine local field potential coherence between these two brain areas as mice explore novel and familiar environments. In more familiar environments, the relationship between running speed and network oscillations is enhanced, a form of plasticity which we hypothesise is driven by the RSC. Furthermore, we have preliminary evidence to suggest that this form of contextual memory-driven plasticity is impaired in a mouse model of Alzheimer's disease. Therefore, we will examine the hypothesis that impaired RSC-MEC interactions underlie these deficits in this neural correlate of spatial memory.
Walsh D, Brown J and Randall A (2020). Neurophysiological alterations in the nucleus reuniens of a mouse model of Alzheimer's disease. Neurobiology of Aging 88:1-10. doi: 10.1016/j.neurobiolaging.2019.12.006