The importance of odors to your taste buds might be greater than you think.
Putu Agus Khorisantono, postdoctoral researcher at the Karolinska Institutet, delves into this.
I am a cognitive and behavioural neuroscientist based in the Department of Clinical Neuroscience (Psychology Division) of Karolinska Institutet, with a background in statistics, functional neuroimaging and neuroeconomics. My main research interest is in food perception and dietary choices, focusing on nutrient-specific sensation and perception as well as reward integration.
Prior to joining KI, I did my PhD with Dr Fabian Grabenhorst in the Department of Physiology, Development and Neuroscience at the University of Cambridge, investigating the role of textural cues in fat-sensing and reward valuation. Currently, I am employed by Dr Janina Seubert as a postdoctoral researcher to study the integration of olfactory and gustatory cues in determining food choices.
Tasting Odours
Have you ever had a cold, and suddenly food tastes bland and uninteresting? You might think there’s an issue with your taste buds, but what you’re missing isn’t taste, but smell – specifically, retronasal odours, which are the aromas that travel from your mouth to your nose through the back of your throat.
This intimate connection between taste and smell is what creates flavour. In fact, a strawberry aroma can seem ‘sweet’ by itself, and my research looks at how this is wired into our brains.
In our recent study, we used functional neuroimaging to look at the brain activation of volunteers as they received sweet and savoury tastes and their matching retronasal odours separately. In doing so, we found that odours activated a neural pattern in the insula, the primary taste cortex, that overlapped with the patterns induced by the tastes themselves. In other words, when we trained an algorithm to differentiate between the sweet-taste and the savoury-taste patterns, it identified that the raspberry aroma pattern as sweet and the chicken aroma pattern as savoury.
What this implies is that there are shared flavour-specific codes between retronasal odours and their associated tastes. This goes against conventional models that suggest that odours and tastes were separately processed until further downstream in the orbitofrontal cortex.
We also found that this shared neural code was strongest in specific parts of the insula that are known to receive signals directly from the olfactory cortex. This implies that, at a very early stage of processing, the brain doesn’t strongly distinguish between tasting sweetness and smelling a sweet aroma in the mouth. This neural overlap is the basis for the beautiful, multisensory experience we call flavour, and it explains why a blocked nose can make the world’s most delicious meal feel utterly flavourless.
Read More:
[Nature] – Tastes and retronasal odours evoke a shared flavour-specific neural code in the human insula
[The Conversation] – Smell triggers the same brain response as taste does – even if you haven’t eaten anything
[EurekAlert!] – Smells deceive the brain – are interpreted as taste
