Tauopathies are a heterogeneous group of neurodegenerative diseases, characterized by the deposition of pathological tau (p-tau) proteins in distinct brain regions. The hypothesised spread of tau pathology between different brain regions is not a well-known process and vulnerable cell types have not been fully identified. Spread of p-tau may disrupt coordination of neural activity, leading to memory and movement impairments. Rhythmic subcortical inputs to the hippocampus e.g. from the medial septum, are required for coordination of cortical activity underlying spatial memory. In this study, my aim is to test the effects of pathological tau on memory and on neuronal activity in affected brain regions in THY-Tau22 mice which are transgenic tauopathy animals, to make predictions about how potential alterations may affect neuronal activity in humans with tauopathy. I also investigated the distribution of p-tau in post- mortem human brain tissue from dementia patients and in similar brain regions in the THY- Tau22 mice and identified vulnerable cell types with different molecular markers using immunohistochemistry. I found that p-tau was enriched in distinct brain regions in both mouse and human, and was localized to distinct kinds of neurons and glia. I performed behavioural tests to assess the spatial working memory and anxiety-related behaviour of transgenic mice. Recording and labelling single p-tau-expressing neurons in vivo may reveal the effects of p-tau on firing patterns, which are potential biomarkers for the pathology and help predict future changes in behaviour.