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Are you a Carbohydrate Craver?

Are you a Carbohydrate Craver?. Affect Modulates Appetite-Related Brain Activity to Images of Food Killgore , W. & Yurgelun -Todd, D. (2006) Vivien Chiu. Introduction. Thorough studies done in labs on animals, but what about us? Higher order regions of cerebral cortex involved in humans

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Are you a Carbohydrate Craver?

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  1. Are you a Carbohydrate Craver? Affect Modulates Appetite-Related Brain Activity to Images of Food Killgore, W. & Yurgelun-Todd, D. (2006) Vivien Chiu

  2. Introduction • Thorough studies done in labs on animals, but what about us? • Higher order regions of cerebral cortex involved in humans • What is Affect? • Conscious subjective feeling/emotion, interaction with stimuli • OBJECTIVE: To determine if cerebral activity would covary with affect ratings and if covariance pattern would differ as a function of food’s nutritional content

  3. Brain Regions • Insular cortex • Ongoing status of internal state • Responds directly to specific taste stimuli changes (salty/sweet) • Increased activation during hunger/smell of food • Orbitofrontal cortices • Gathers info to converge them and evaluate overall reward potential • Medial/caudal: Heightened activity with motivation to eat • Lateral: inhibitory function related to satiety

  4. Methods • Participants • 13 healthy (mean BMI = 22.1 kg/m2 ) women, ranging from 21-28 years old • Imaging Methods • Over 20 contiguous coronal slices were used to collect images from blood oxygen level dependent (BOLD) fMRI • Each scan lasted 150s, with 50 images collected each time

  5. Methods • Stimulation • Three separate scanning runs: • lasted 150s each  5 alternating 30s periods with control and stimulus  10 pictures per period High-fat/calorie-dense foods Non-edible food related objects Low-fat/calorie-lean foods

  6. Methods • PANAS (Positive and Negative Effect Schedule) • PA • Pleasant enthusiasm • Active positive engagement • NA • Subjective distress • Unpleasant emotional activation

  7. Results

  8. Results Summary • High Calorie Foods • PA with greater BOLD activity in right lateral orbitofrontal cortex • Higher NA ratings were associated with greater BOLD activity within medial regions of orbitofrontal cortex/ posterior insula • Low Calorie Foods • Greater PA seen in with increase of BOLD activity from orbitofrontal cortex • Higher NA associated with increased BOLD activity in right lateral and anterior insula (might be difference between anterior and posterior)

  9. Discussion • Responsiveness/feeding related regions of brain were significantly related to PANAS ratings • Medial orbitofrontal rewarding stimuli • Lateral orbitofrontal punishing stimuli/inhibition of stimuli response • Proposed mechanism • Relation between mood and appetite involve changes in activity of orbitofrontal cortices • Negative mood/stress  increased cravings • “Self-medicate”  high carbs = increasing serotonin

  10. Conclusions • Opinion on paper • Strengths: • Implications for people with seasonal affective disorder or bipolar depression • Underlying message about food choice • Limitations: • fMRI in-plane distortion • Small sample of only females in a limited age range working at the same hospital in Massachusetts • Correlation does not mean causation • Next steps? • Specifically correlating individual food cravings

  11. Summary • Affective state influences brain activity in response to food of varying calorie density/fat content • Negative mood • Unhealthy food choice association  shun low-calorie, low-fat • Positive mood • Fewer cravings for foods high in calorie/fat content • Neurobiological mechanism may be involved between mood and food choice • Right lateral medial cortex: Reduced motivation to eat • Medial orbitofrontal/insular cortices: Increased desire to eat

  12. Questions? Don’t be an emotional eater, be AWESOME instead

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