DrSamuel Barnes

The goal of my research is to understand the role of neural circuit plasticity in aging and neurodegeneration and use this information to develop interventions that promote healthy cognition.

After graduating from Oxford University in 2006, I was awarded an MRC capacity building PhD. studentship at King’s College London to investigate the functional signatures of synaptic connection loss in the cortex. My postdoctoral work (UCL) used in-vivo imaging, to investigate how homeostatic plasticity regulates neuronal activity and prevents synapse loss in adult cortex. This work led to the discovery of local synaptic homeostasis in small neuronal-subnetworks and dendritic branches. In October 2015, I won the internationally competitive Safra Fellowship, an award which supports early career researchers as they tr­ansition to independence, and joined Imperial College London in the Department of Brain Sciences.

In April 2018, I was awarded a UK Dementia Research Institute (UK DRI) Fellowship and became a lecturer in the Department of Brain Sciences at Imperial College London. In September 2022, I was promoted to Senior Lecturer in Neural Plasticity and in April 2023 successfully underwent UK DRI renewal, providing long-term funding support until 2030. In April 2024, I was appointed Deputy Director of the UK DRI Centre at Imperial, and more recently (September 2025) I was promoted to Reader (Associate Professor) in Neural Plasticity.

My group focuses on homeostatic plasticity mechanisms that regulate neural firing-rate activity within a stable dynamic range, preventing prolonged periods of hyper- or hypo-activity. We hypothesise that homeostatic control is neuroprotective but may fail in aging and the early stages of neurodegeneration leading to pathophysiological neural-circuit activity.

To test this hypothesis, we use a combination of electrophysiology, 2-Photon calcium imaging and 1-Photon brain-wide imaging. My group combines these approaches with molecular measures such as transcriptomics and spatial proteomics to probe the mechanisms involved in homeostatic control, as well as behavioural testing to measure the consequences of destabilised neural-circuit activity.

My work to date has led to publications in journals including Neuron, Science, Nature Communications and Nature Neuroscience, and a series of human experimental medicine trials currently in progress. The associated projects are funded by the MRC, UK DRI, ARIA, The BBSRC, Alzheimer’s Society, The Alzheimer’s Association, The BrightFocus Foundation, The Uren Foundation, The Wellcome Trust, The Epilepsy Research Institute and The Rosetrees Trust.

Our work is some of the first to show that synaptic homeostasis becomes less effective with age, and that this can impair learning in older animals. We also find that some pharmacological approaches can alleviate cognitive impairments associated with failing homeostatic plasticity in old mice. This suggests that these plasticity processes could be rescued in later life and have positive consequences for ageing cognition. This work has led to the Bayliss-Starling Prize in physiology.

https://www.physoc.org/news_article/congratulating-our-2026-prize-lecture-recipients/