Researchers have discovered how taste is encoded in patterns of neural activity in the human brain.
A
team of researchers from the German Institute of Human Nutrition in
Potsdam and the Charite University Hospital in Berlin made the
discovery.
The ability to taste is crucial for food choice and the formation of food preferences.
"Impairments
in taste perception or hedonic experience of taste can cause deviant
eating behaviour, and may lead to malnutrition or supernutrition," said
lead researcher Kathrin Ohla.
"This knowledge is essential for the development of strategies to moderate deviant eating behaviour," Ohla noted.
Tastants in the mouth activate specific receptors on the tongue
corresponding to each of the basic tastes: sweet, salty, sour, bitter,
and savoury. The signal is then transduced further to the brain.
"This would be an important step to understanding how individual
taste preferences are coded in the brain and of high relevance for
clinical applications such as weight loss programmes," said
co-researcher Niko Busch.
In the study, participants discriminated between sweet, salty, sour,
and bitter tastants while their brain activity was recorded with
electroencephalography (EEG) - a method that measures minuscule
electrical signals generated by billions of neurons in the human
neocortex.
Different tastes evoked different dynamic patterns of electrical
activity. A machine learning algorithm could be trained to discriminate
between these patterns.
Thus, given a piece of data, the algorithm could decode from the
pattern of brain-wide activity which taste a participant had received in
that moment.
This form of "mind reading" even made it possible to decode which of
four tastants participants thought to have tasted when they were, in
fact, incorrect.
The tastes that participants frequently confused with each other
(e.g. sour and salty) were also frequently confused by the algorithm.
"The findings suggest that quality is among the first attributes of a
taste represented in the central gustatory system," Ohla said.
The study was published in Current Biology.
