Sabine Frank-Podlech ● Jaana M. Heinze ● Jürgen Machann ● Klaus Scheffler ● Guido Camps ● Andreas Fritsche ● Melanie Rosenberger ● Jörg Hinrichs ● Ralf Veit and Hubert Preiss
Background: The amount of fat in ingested food dictates specific activation patterns
in the brain, particularly in homeostatic and reward-related areas. Taste-specific brain
activation changes have also been shown and the sensitivity to the oral perception
of fat is associated with differential eating behavior and physiological parameters. The
association between oral fat sensitivity and neuronal network functions has, however,
not yet been defined.
Objective: We aimed to investigate the association between fat-dependent neuronal
functional connectivity patterns and oral fat sensitivity.
Design: To investigate the underlying changes in network dynamics caused by fat
intake, we measured resting-state functional connectivity in 11 normal-weight male
participants before and after a high- vs. a low-fat meal on two separate study days.
Oral fat sensitivity was also measured on both days. We used a high-resolution
functional magnetic resonance imaging (MRI) sequence to measure any connectivity
changes in networks with the seed in the brainstem (nucleus tractus solitarii, NTS), in
homeostatic (hypothalamus) and in reward regions (ventral and dorsal striatum). Seedbased
functional connectivity (FC) maps were analyzed using factorial analyses and
correlation analyses with oral fat sensitivity were also performed.
Results: Regardless of fat content, FC between NTS and reward and gustatory areas
was lower after ingestion. Oral fat sensitivity was positively correlated with FC between homeostatic regions and limbic areas in the high-fat condition, but negatively correlated
with FC between the dorsal striatum and somatosensory regions in the low-fat condition.
Conclusion: Our results show the interaction of oral fat sensitivity with the network
based neuronal processing of high- vs. low-fat meals. Variations in neuronal connectivity
network patterns might therefore be a possible moderator of the association of oral fat
sensitivity and eating behavior.