Overview
This PhD project investigates the neural basis of changes in cognitive performance during exposure to body malodour. Using advanced neuroimaging techniques like EEG and fMRI, the research aims to improve our understanding of the central mechanisms of cross-modal olfactory processing on cognitive functioning using a negatively valanced odour. Conducted through a collaboration between the University of Liverpool and Unilever, the project combines academic research with real-world applications.
About this opportunity
Olfaction (i.e. the sense of smell) serves a key function in human survival through driving approach and avoidance behaviour for external stimuli. This is thought to result from the privileged access that olfaction has to affective brain networks1. In support of this, brain imaging research has demonstrated an overlap in activity for both affective and olfactory processing in the amygdala, hippocampus, insula, anterior cingulate cortex, and orbitofrontal cortex2. Beyond sensory and affective processing, the olfactory system has also been implicated in many other neural functions which are widely-distributed across the brain. Recent functional connectivity analyses identified a human olfactory network spanning both cortical and subcortical regions across the temporal and frontal lobes; areas associated with higher order cognitive processes such as attention, memory and executive function3. This suggests that olfaction may have cross-modal impact across a variety of neurocognitive processes.
Recent work from our lab (https://www.liverpool.ac.uk/population-health/research/groups/unilever-brain-behaviour-collaboration/) has begun to elucidate the brain dynamics underpinning the cross-modal impact of olfaction. We have identified associations between pleasant olfactory stimuli with visual and affective processing4 ,and have established cross-modal modulation of fragrance valence on processing of facial expressions (e.g. unpleasant fragrances differentially modulate Event-related potentials (ERPs) for happy and disgusted faces5). Taken together these suggest that: 1) fragrances can have a cross-modal impact on brain processing of non-olfactory stimuli; 2) odour can modulate the neural signature underpinning valence and affective processing.
One area that is under-researched is the potential cross-modal impact of the olfactory system on higher order cognitive functions. For example, Arnold et al. 3 suggested olfactory processing is impacted by damage to parts of the frontal lobe lying dorsal and lateral to the orbitofrontal cortex. Given that these structures contribute to performance on executive functioning tasks it is unsurprising that there is an emerging theoretical perspective for a cross-modal relationship between olfaction and cognitive function6.
Recent resting-state fMRI work has attempted to characterise the impact of smells on brain functioning and to differentiate the neural signatures of their valence7. It was found that unpleasant smells in particular predicted greater connectivity between insula, hippocampal, and prefrontal areas, which potentially reflects enhanced aversive learning and avoidance motivation. Hence, we hypothesise that negatively valenced odours may have particularly pronounced cross-modal effect on cognitive functioning – perhaps by drawing on limited attentional resources in the brain. However, to date effects of negatively valenced odours on higher order cognitive performance, and the neurophysiological correlates of this cross-modal effect have yet to be explored.
Our project aims to improve our understanding of the central mechanisms of cross-modal olfactory processing on cognitive functioning using the negatively valanced odour of body malodour. The findings will contribute to fundamental neuroscience and have real-world impact to support product development.
We will address this challenge through a series of studies with the following objectives:
- Assess how body malodour impacts cognitive performance on neurocognitive / executive functioning tasks
- Use EEG to assess how body malodour modulates ERP components associated with cognitive performance
- Use fMRI to assess cross-modal impact of body malodour in cognitive and affective brain activity and network connectivity
The Department of Psychology at the University of Liverpool is a vibrant research institute, with over 60 academics and more than 70 PhD students. The department includes three EEG labs equipped with advanced stimulus control, data acquisition and analysis workstations. The successful candidate will join a collaborative research group of five PhD students working on aligned neuroimaging projects. MRI scanning will take place on campus in the Liverpool Magnetic Resonance Imaging Centre (LiMRIC), which houses a Siemens 3T scanner and is supported by full-time radiographers. Together, these facilities provide a robust infrastructure for successful completion of high-quality experimental studies and to support the student’s development.
As part of this PhD, the successful candidate will also undertake an industrial placement with Unilever’s Biosciences team at the Port Sunlight Research Lab. The long-standing collaboration between the University of Liverpool and Unilever has supported UKRI-funded PhD students since 2010, offering a unique opportunity to bridge academic research with real-world application.