Dr Tim Viney

Research interests

My research focuses on how the coordinated activity of diverse kinds of neurons contributes to behaviour. I have a general interest in how different subcortical inputs to the hippocampus affect rhythmic network activity via their postsynaptic target neurons, and their impact on the processing of mnemonic functions including spatial navigation. Recent work has involved investigating the synaptic circuit mechanisms for how different kinds of GABAergic neurons in the medial septum (part of the basal forebrain) implement rhythmic neuronal activity in the cortex, especially during theta network oscillations. Current research includes defining how the expression of hyperphosphorylated human tau affects behaviour, neuronal and network activity in the temporal mnemonic system of a mouse tauopathy model. We are also defining cell types that are affected in human tauopathies using immunohistochemistry in high quality human brain sections (collaboration at KOKI, Budapest). Current funding sources: MRC, Alzheimer's Society, John Fell Fund, Medical Sciences Internal Fund.

Biography

I carried out my PhD in the group of Dr Botond Roska at the Friedrich Miescher Institute in Basel, where I studied neural circuits of the retina (2005-2010). I defined several types of ganglion cells in a transgenic mouse line based on two-photon targeted patch clamp recordings in wholemount retinas. I demonstrated that "approach sensitive" ganglion cells receive glycinergic inhibition from AII amacrine cells, and that dopaminergic interplexiform cells are presynaptic to a type of intrinsically photosensitive ganglion cell. Next I moved to Oxford as an MRC Career Development Fellow in the group of Professor Peter Somogyi at the MRC Anatomical Neuropharmacology Unit (2010-2012). Here I investigated the spike timing of identified GABAergic neurons in the rat hippocampus in relation to different behavioural states. I also discovered a 'negative marker' for axo-axonic cells, the transcription factor SATB1. In 2012, I became an MRC Investigator Scientist, and I was a Junior Research Fellow at Wolfson College 2013-2019. Recently, I discovered a specialised kind of rhythmically-bursting GABAergic neuron in the mouse medial septum that selectively innervates GABAergic neurons in the dorsal presubiculum and entorhinal cortex, named orchid cells (Viney et al eLife 2018), and defined a group of 'low rhythmic neurons' of the medial septum that preferentially target the dentate gyrus and CA3 (Salib et al J Neurosci 2019). In 2020 I became a Research Fellow at Wolfson College.

Techniques

Single neuron extracellular recordings and juxtacellular labelling in awake mice and rats; retrograde and anterograde viral tracing; immunohistochemistry; neuronal reconstructions; light, fluorescence and electron microscopy; behavioural testing in real and virtual environments; multi-unit recordings; analysis of spike timing and network oscillations.

Keywords

Hippocampus, medial septum, thalamus, GABAergic interneurons, pyramidal cells, theta oscillations, gamma oscillations, sharp wave ripples, entorhinal cortex, tauopathy, neurodegeneration, neuroanatomy, neurophysiology, in vivo.

Supervision

M. Salib (DPhil student, 2015-2019) [Co-supervisor: Prof V. Vyazovskiy, DPAG, Oxford]

B. Sarkany (Erasmus+ student, 2019-)

Dr S. Hasan (short-term postdoc, 2018)

Dr L. Lefevre (short-term postdoc, 2018)

C. Onyali (MSc student, 2018)

M. Vezir (Erasmus student, 2016)

M. Salib (MSc student, 2014-2015)

M. Valero (Visiting PhD student, 2014)

M. Crump (DPhil student, 2012-2014) [Co-supervisor]

D. Kotzadimitriou (Research Assistant, 2011-2012)