Can non-invasive vagus nerve stimulation condition preference for new flavors paired with low-fat foods ?
Thu-S11-005
Presented by: ilkim BÜYÜKGÜDÜK
Conditioned flavor preference can be formed when a novel flavor is associated with for example palatable taste and/or with positive post-digestive effects. Recent research on the vagus nerve (VN) using chemogenetic and optogenetic stimulation has shown that vagal gut-brain communication underlies this learning. If VN activity triggers food reward, we predict that non-invasive VN stimulation (nVNS, compared to pseudo-stimulation) will condition liking for new flavors paired with low-fat foods.
In order to select flavors for conditioning, 17 participants tasted and rated 10 flavors using the sip-and-spit method. The participants rated liking and wanting. Two flavors that are similarly near to neutral in liking were chosen for the conditioning sessions. To induce associative conditioning, we coupled one low-fat stimulus with nVNS and another low-fat stimulus with sham stimulation in a counterbalanced within-participant design. The paired stimuli were then presented to the subjects for 20 days. At the end of conditioning sessions participants were asked to taste and rate 10 flavors again, as they did before the conditioning sessions.
No significant interaction between time (before vs after conditioning) and condition (nVNS vs sham) was identified in either the liking or wanting ratings. However, participants' flavor wanting scores increased over time, but this main effect of time was statistically significant only in the nVNS condition (p=.024).
Our initial result shows that VN stimulation does not readily condition flavor liking in humans as it does in animals. Despite this, it shows that nVNS has a potential positive effect on increasing the participants' desire to consume more new flavors paired with low-fat foods. Further research is necessary to understand the specific impact of nVNS on the progression of flavor wanting scores.
Funded by TÜBİTAK(118C299)
In order to select flavors for conditioning, 17 participants tasted and rated 10 flavors using the sip-and-spit method. The participants rated liking and wanting. Two flavors that are similarly near to neutral in liking were chosen for the conditioning sessions. To induce associative conditioning, we coupled one low-fat stimulus with nVNS and another low-fat stimulus with sham stimulation in a counterbalanced within-participant design. The paired stimuli were then presented to the subjects for 20 days. At the end of conditioning sessions participants were asked to taste and rate 10 flavors again, as they did before the conditioning sessions.
No significant interaction between time (before vs after conditioning) and condition (nVNS vs sham) was identified in either the liking or wanting ratings. However, participants' flavor wanting scores increased over time, but this main effect of time was statistically significant only in the nVNS condition (p=.024).
Our initial result shows that VN stimulation does not readily condition flavor liking in humans as it does in animals. Despite this, it shows that nVNS has a potential positive effect on increasing the participants' desire to consume more new flavors paired with low-fat foods. Further research is necessary to understand the specific impact of nVNS on the progression of flavor wanting scores.
Funded by TÜBİTAK(118C299)