Recipient organisationNIHR Wellcome Trust Imperial Clinical Research Facility
NIHR supportRecorded as supported by this research centre
PeriodMar 2025 — Mar 2026
In plain English
AI plain-English summary
A new fMRI scanning protocol now allows researchers to see, for the first time, the tiny appetite-control centres deep in the brainstem and hypothalamus that were previously invisible to standard scanners. This matters because obesity costs the NHS billions and causes significant illness and death, yet only a small fraction of eligible patients can access bariatric surgery, and some do not lose weight successfully even after surgery. Previous fMRI studies, using techniques from 10–15 years ago, were too low-resolution to image these small brain areas accurately. Without seeing what happens in the hypothalamus and brainstem, scientists cannot understand why some patients respond well to weight-loss treatments while others do not. If this pilot study succeeds, it will enable downstream research comparing brain activation between “responders” and “non-responders” after bariatric surgery, and reveal how gut hormones affect appetite centres in both obesity and cachexia. The ultimate goal is to identify new relationships between appetite centres and energy balance that could be targeted by improved pharmacotherapy. This is a technical optimisation study—its immediate output is a better imaging tool, not a new drug—but without this tool, the fundamental neuroscience needed to develop better weight-loss treatments remains out of reach.
View original technical description
Obesity represents a major cost to the NHS as well as a significant cause of morbidity and mortality. However, only a small proportion of the eligible obese population has access to bariatric surgery, and some do not achieve successful weight loss. It is therefore important to understand underlying mechanisms to successful weight loss which may translate to improved pharmacotherapy for weight loss. fMRI is a useful tool to understand the relationship between the key appetite centres such as the hypothalamus and energy balance. Previous functional brain imaging studies have shown activation of appetite- and reward-associated cortical areas such as the insula, amygdala, putamen, and orbitofrontal cortex on functional MRI (fMRI) to be reduced in RYGB subjects compared to weight-matched controls. We have also previously shown divergent brain activation patterns on fMRI, following matched weight loss with RYGB compared to VLCD. These studies have used techniques from 10-15 years ago which were low resolution and unable to image small areas of interest such as the hypothalamus accurately. In addition, imaging of areas of interest in the brainstem was not possible because of the location of the areas and their small size. In this study, we intend to use a blood-oxygen level dependent (BOLD) fMRI method, utilising a new protocol that takes advantage of technical advancements over the last 10 years to allow for high-resolution functional imaging of the hypothalamus and brainstem. Optimisation of this technique will allow its application in downstream studies exploring brain activation between “responders” and “non-responders” with regards to effective weight loss after bariatric surgery and in understanding the effects of gut hormones on appetite centres in obesity and in cachexia. This will potentially highlight new relationships between the appetite centres and energy balance, which may be targeted in the development of new or improved pharmacotherapy.
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