Multisensory integration: olfaction and metabolism

Rationale: When we switch from hungry to satiated our perception of odours is changed, we become less sensitive and find food odours less appealing. Recent research has highlighted an unappreciated role of olfaction in regulating metabolic health. However, we do not yet know how our metabolic state interacts with our sense of smell or how this cross sensory modulation influences metabolism. Such knowledge could prove useful in addressing metabolic disorders such as obesity.

Plan of work: This project has 4 objectives that aim to determine how associating an odour with food changes brain activity, how changes in the level of satiety alter the brain activity responsible for processing odours and how these changes result in altered perception, feeding behaviour and metabolism. We will use advanced imaging methods to measure the activity of different neuronal components that make up the brain’s circuitry and will observe how these respond to odours before and after learning or the manipulation of satiety. Using pharmacological tools, we will identify the receptors responsible for detecting satiety and causing a change in brain activity. We will then use genetic techniques to selectively knockdown these targets and thus preventing satiety modulation of brain activity. This strategy will allow us to determine how this cross sensory modulation alters perception, feeding behaviour and metabolism and whether it is a viable target for addressing metabolic disorders.

Animal welfare: The majority of procedures will be carried out under terminal anaesthesia which eliminates distress and discomfort. In some cases, animals will receive surgery under anaesthesia and will be allowed to recover with appropriate pain relief. A small number of these animals will be habituated to head restraint with food rewards after which their brain activity will be imaged humanely in the conscious state, this procedure causes minimal distress to the animals. During all procedures the distress and discomfort of animals will be closely monitored and minimised, if for any reason this is not possible the procedure will be terminated. 

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