are you a carbohydrate craver?
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
AFFECT MODULATES APPETITE -RELATED BRAIN ACTIVITY TO IMAGES OF FOOD
KILLGORE, W. & YURGELUN-TODD, D. (2006)
VIVIEN CHIU
Are you a Carbohydrate Craver?
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
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
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
Methods
Stimulation Three separate scanning runs:
lasted 150s each 5 alternating 30s periods with control and stimulus 10 pictures per period
Low-fat/calorie-lean foods
High-fat/calorie-dense foods
Non-edible food related objects
Methods
PANAS (Positive and Negative Effect Schedule) PA
Pleasant enthusiasm Active positive
engagement NA
Subjective distress Unpleasant emotional
activation
Results
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)
Discussion
Responsiveness/feeding related regions of brain were significantly related to PANAS ratings Medial orbitofrontal rewarding stimuli Lateral orbitofrontal punishing stimuli/inhibition of
stimuli responseProposed mechanism
Relation between mood and appetite involve changes in activity of orbitofrontal cortices Negative mood/stress increased cravings “Self-medicate” high carbs = increasing serotonin
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
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
Questions?
Don’t be an emotional eater, be AWESOME instead