Effects of non-invasive, transcutaneous Vagus Nerve Stimulation (tVNS) on food reward systems were shown before in animals and humans. However, the optimal stimulation location on the ear for the Auricular Branch of VN is still under discussion. Two main candidate locations are Cymba Concha and Tragus. In our experiment we tested stimulation of these two locations as well as the combination of both. Earlobe-helix combination stimulation was used as the sham condition. Using electroencephalogram (EEG) is advantageous in terms of observing the near-instantaneous effects on neural activity (in miliseconds). Other advantages of using EEG are reduced cost and the ability to include participants with a higher BMI (compared to fMRI). In addition, since the participant is seated, EEG allows for a more naturalistic eating context. Since the swallow breath contains flavor, the absence of event‐related EEG studies using sip‐and‐swallow protocols is a crucial gap. Here we present data from a sip‐and‐swallow protocol with event‐related EEG responses time‐locked to swallowing of a food stimulus (cacao milk). The participants sipped the stimulus for 50 trials per block upon hearing an auditory cue. A pair of EMG (electromyogram) electrodes, for detecting muscle activity, were connected on the submental muscle under the participants’ chin and utilized for detection of swallowing to obtain the exact time point for consumption. We have completed data collection with 15 participants (4 EEG sessions per participant for each stimulation location). Ongoing data analyses are done with EEGLAB and ERPLAB on MATLAB and with MNE on Python. In addition to comparing the responses to stimulation from different locations, we demonstrate that a sip-and-swallow EEG protocol is possible in terms of data quality.

FUNDING:
2232 International Fellowship for Outstanding Researchers Program of TÜBİTAK (Project No. 118C299) to MV.
Giract European PhD in Flavor Research Awards 2020/2021 first year PhD to SA.