Insulin modulates food-related activity in the central nervous system.
BACKGROUND
Previous data suggest a key role of central nervous insulin action in regulating energy homeostasis.


OBJECTIVE
We therefore investigated whether insulin modulates brain responses to food and nonfood pictures in a functional magnetic resonance imaging study.


METHODS
Nine healthy, normal-weight subjects underwent two functional magnetic resonance imaging measurements to compare the effects of insulin and placebo administration during a visual recognition task with food and nonfood pictures. Insulin was administered intranasally to raise insulin concentrations in the cerebrospinal fluid without altering systemic effects in the periphery. Metabolic parameters were continuously determined during the experiments.


METHODS
We measured the changes in brain activity after intranasal insulin administration.


RESULTS
Food pictures were detected faster when compared to nonfood pictures in all conditions without any effect of placebo or insulin. After insulin application, functional magnetic resonance imaging measurements showed a significantly reduced activity in the presence of food pictures compared to placebo in the right and left fusiform gyrus, the right hippocampus, the right temporal superior cortex, and the right frontal middle cortex. The brain activation induced by nonfood pictures remained unaffected by insulin.


CONCLUSIONS
We demonstrate that intranasal insulin led to a reduction of activity in brain areas related to object processing and memory and may have an effect on brain activation with regard to the processing of food pictures. This effect might be part of a mechanism that terminates food intake in the postprandial state.
Guthoff
Martina
M
MEG-Zentrum, Otfried-Müller-Strasse 47, 72076 Tübingen, Germany.
Grichisch
Yuko
Y
Canova
Carlos
C
Tschritter
Otto
O
Veit
Ralf
R
Hallschmid
Manfred
M
Häring
Hans-Ulrich
HU
Preissl
Hubert
H
Hennige
Anita M
AM
Fritsche
Andreas
A
D000281:Administration, Intranasal; D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D004435:Eating / Q000502:physiology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes; D010100:Oxygen / Q000097:blood
D007328:Insulin; D010100:Oxygen