Processing of food-relevant visual stimuli measured by magnetoencephalography and its modulation by insulin Katarína Porubská a,b, ⁎ , Otto Tschritter c , Andreas Fritsche c , Hans-Ulrich Häring c , Niels Birbaumer a , Hubert Preissl a,d a Institute of Medical Psychology and Behavioral Neurobiology, University Tübingen, Germany b Department Pathophysiology of Vision and Neuro-Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany c Medical Clinic, Department of Endocrinology and Metabolism, University Hospital Tübingen, Germany d Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, USA Abstract. Obesity is a major factor for the development of diabetes mellitus type 2 and the number of obese subjects increases especially in industrial countries. Insulin is a central nervous inhibitor of appetite and the peripheral insulin resistance is pathogenetic for diabetes mellitus type 2. We measured the cortical activity of humans after stimulation with pictures showing food or non-food related objects using whole-head magnetoencephalography (MEG) and investigated whether this activity is influenced by insulin. The MEG measurements were performed in 15 healthy humans during a hyperinsulinaemic-euglycaemic clamp in a placebo-controlled single-blind cross-over design. Every subject underwent 2 MEG recordings consisting of 3 blocks each (baseline, 1st level insulin/placebo infusion, 2nd level insulin/placebo infusion). The food stimuli elicited greater neuronal activity for the first component of the visual evoked response if compared to the control pictures ( p = 0.050). There was a tendency of insulin to attenuate the difference between the neuronal activity for the food and the control pictures. These results suggest that there is a differential processing of food stimuli in human brain already in the early visual processing. Insulin can be a modulator of the central nervous processing of the nutritional stimuli. © 2007 Elsevier B.V. All rights reserved. Keywords: Magnetoencephalography; Food; Insulin; Visual; Diabetes International Congress Series 1300 (2007) 516 – 519 www.ics-elsevier.com Abbreviations: fMRI, functional magnetic resonance imaging; PET, positron emission tomography; MEG, magnetoencephalography. ⁎ Corresponding author. MEG-Centre, Institute of Medical Psychology and Behavioral Neurobiology, Otfried- Müller-Str. 47, 72076 Tübingen, Germany. Tel.: +49 7071 2987704; fax: +40 7071 295706. E-mail address: katarina.porubska@med.uni-tuebingen.de (K. Porubská). 0531-5131/ © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2007.01.010