Everyone is looking for that weight loss program that will shed those unwanted pounds. Many try several before finding one that works, and some never succeed. What if you could do an fMRI scan that would tell you whether a weight loss program was likely to be effective? BGU researchers have discovered for the first time a neural subnetwork that corresponds to the gastric basal electric frequency and whose patterns of connectivity predict future weight loss.
Their findings were just published in the journal NeuroImage.
A multidisciplinary team of BGU scientists approached the problem from both ends - brain and body. The team's findings support a prevalent neural theory of impaired weight regulation, the over-sensitivity to palatable food cues. According to the theory, people with an increased neural response to seeing and smelling food overeat on a regular basis thereby gaining weight.
The team assessed 92 people during an 18-month lifestyle weight loss intervention. Prof. Iris Shai (pictured above), of BGU's Department of Epidemiology, led the intervention entitled DIRECT-PLUS. Shai is well-known for her long-term dietary intervention studies conducted at the Negev Nuclear Research Center in Dimona. The participants were chosen for large waist circumference, an abnormal level of blood lipids and age. Before the intervention, the participants underwent a battery of brain imaging scans and behavioral executive function tests. The participants' weight loss was measured after six months in which, according to Prof. Shai, the maximum weight loss is generally achieved.
The team found that the subnetwork of brain regions corresponded more closely to basic sensory and motor regions rather than higher, multi-modal regions.
“To our surprise, we discovered that while higher executive functions, as measured behaviorally, were dominant factors in weight loss, this was not reflected in patterns of brain connectivity. In other words, weight loss is not merely a matter of willpower, but is rather connected to much more basic visual and olfactory cues," says Gidon Levakov, a graduate student, who led the study from the Department of Brain and Cognitive Sciences and a member of the Zlotowski Center for Neuroscience at BGU.
Instead, the researchers found a connection between the stomach basal electric rhythm within the subnetwork and weight loss. That rhythm governs the gastric waves that are associated with hunger and satiety. They also found that the pericalcarine sulcus, the anatomical location of the primary visual cortex, was the most active node in this subnetwork.
“It appears that visual information may be an important factor triggering eating. This is reasonable, given that vision is the primary sense in humans" says principal investigator, Prof. Galia Avidan, who has been studying the visual system for many years. She is a member of the Departments of Brain and Cognitive Sciences and Psychology as well as the Zlotowski Center for Neuroscience at BGU.
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