There are some of us who wish to get rid of urges for potentially unhealthy indulgences such as eating a lot of sweet-things at one time. But, unfortunately, the brain does not work that way! In fact, some experts assert that overeating is a neurological disorder. In addition, the enjoyment derived from eating pleasant-tasting foods is also almost inextricably tangled up with emotional and psychological responses of various kinds. This may explain why conditions such as this are so hard to treat.
A team of researchers from Columbia University’s Zuckerman Institute has investigated some facets of this phenomenon in an animal study. The basis for their experiments was a colony of mice in which the specific neural tissue and connections associated with different tastes in the amygdala could be 'switched off.'
Previous work has shown that the brain’s taste center is connected to specific termini in the amygdala. This was a groundbreaking find as the amygdala is associated with emotional responses to stimuli, not taste processing.
Furthermore, the group also reported that the neurons in the taste center for sweet and bitter tastes had their own distinct destinations in the amygdala. This suggests that different tastes are, or become, related to different emotional states.
Tasting with Your Brain
Normally, ‘targets’ in the amygdala are quiescent until they are activated by their respective taste connections from that cortex of the brain (which, in turn, is connected to nerves running from the tongue).
However, the Zuckerman Institute researchers found a way to control this externally in their test mice. When they switched on the ‘sweet taste’ tissue in the amygdala, they found that the rodents reacted to plain water with the same amount of enthusiasm as normally reserved for sugar. Another type of neurological switch could cause the mice to perceive sweet tastes as bitter. This caused the mice to react to sugar in the same way as they did a sour-tasting analog or vice versa.
Mice like treats as much as we do, for apparently similar reasons too. (Source: Meditations/pixabay.com)
Turning Off the Need for Sweets
These results required that the scientists manipulated the connections from the taste cortex-ends as well as those in the amygdala. When they left the amygdala-ends on, they found that the mice appeared to recognize different tastes as normal.
However, the team also failed to exhibit the normal behavioral responses to experiencing either sweet or sour. The researchers likened these responses to a sudden absence of the impulse to abuse food in a patient who would normally be inclined to binge when presented with their favorite treats.
Therefore, this research may have important implications for the treatment of various addictions and, possibly, their underlying psychological roots. However, it would require much more extensive validation, elaboration, and up-scaling of the Zuckerman team’s project.
In more immediate terms, it is an important piece of evidence for the links between foodstuffs, especially different-tasting ones, and brain activity beyond the taste cortex. For example, it now appears that this activity is much more pervasive and prevalent than once thought. On the other hand, different components of it (such as the connections that determine the enjoyment of different tastes) can be isolated with increasing precision.
Brain Switches: The Future of Addiction Treatment?
All in all, this project is a potentially vital component of next-generation neuroscience research and understanding. There are also numerous future directions for this branch of study. For example, the long-term effects of taste cortex/amygdala connectivity could be elucidated.
This area of the brain could also be implicated in certain conditions; therefore, its study could lead to improved treatments for the same, one day. In the meantime, it seems we will have to continue relying on our willpower to keep from eating all the chocolate left in the fridge (again)!
Top Image: Taste cortex neural connections (sweet=green and bitter=red) find their targets in a mouse-brain amygdala. (Source: Li Wang/Zuker Lab/Columbia's Zuckerman Institute)