Gastric modulation of startle eye blink

Abstract: Previous assessment methods of gastric interoception either
rely on self-reports, or imply invasive procedures. We investigated the
reliability of startle methodology as a non-invasive alternative for the
assessment of afferent gastric signals. Twenty-four participants were
tested on three separate days, on which they were requested to ingest
water (either 0, 300 or 600 ml), after 8 h of fasting. On each assessment
day, eye blink responses (EMG) to 10 acoustic startle stimuli (105 dB)
were assessed at 4 measurement points (before, 0, 7, 14 min. after
ingestion). Increased normogastric responses (EGG), ratings of satiety
and fullness, and higher heart rate variability (RMSSD) suggested
effective non-invasive induction of gastric distention. Startle responses
were lower directly after ingestion of 600 ml as compared to earlier and
later measurements. These results suggest that startle methodology
provides a reliable method to investigate afferent gastric signals. It
could be useful to study possible dissociations between subjective
reports and objective afferent gastric signals in eating or somatoform
disorders.