Tech Breaking
Scientists have found a slow signal that runs from the gut to the brain and teaches us to enjoy food that makes us feel good, a discovery that explains why coffee is widely loved despite its strong, bitter taste . This dopamine signal enables the brain to learn about the nutrient content of food, say researchers from the University of California, San Francisco. While previous studies have revealed the fast-acting pathways of dopamine and how they guide behaviour, the brain hormone ’s slow-acting side has remained elusive, scientists say.
Now researchers have identified the brain cells and nerve connections that process information about taste and nutrients together based on slow signals arriving from the gut. “Here we identify a dopamine pathway that enables learning about the nutrient content of food,” scientists wrote in the study published in the journal Nature . Coffee cups are pictured in a tasting area (AFP via Getty Images) A specific pathway linking dopamine-producing neurons in the brain's ventral tegmental area (VTA) to a region called the anterior basolateral amygdala (aBLA) has been found to play a key role.
This pathway helps the brain to associate a food's flavour with its nutritional value, according to the study. The digestive system also detects nutrients in food and communicates this information to the brain, the study found. In the study, scientists delivered glucose water or a milkshake-like liquid directly into the stomachs of mice, bypassing taste.
They found that nutrients caused the sustained release of dopamine in a brain region called the basolateral amygdala. Researchers found that when these dopamine-releasing nerve fibres were artificially stimulated, the mice came to prefer calorie-free flavour after tasting it. This system is what drives humans to learn to like some foods, such as coffee, over time, researchers say.
The VTA dopamine neurons, according to the study, are key to the brain updating food preferences when animals receive new information about a food's nutritional value. The research reveals how the brain connects flavour information from food with delayed nutritional signals from the gut. It raises the possibility that people’s food preferences could one day be adjusted with targeted treatments.
“These findings establish a neural basis for how animals learn about the nutrient content of their food,” scientists wrote. They explain how coffee could become something one actively craves through repeated experience, they say. “Once your brain has learned to associate the flavour of your favourite brew with the uplift from caffeine, coffee starts to taste a lot better,” study senior author Zachary Knight told SciNews.
Source: The Independent
