Neuronal and Behavioral Effects of Implicit Priming in Obese Individuals
Condition: Feeding Behavior; Obesity; Overweight
MeSH terms: Overweight
Study type: Interventional

Summary: 
      The overall goals of this project are to determine the impact of an implicit priming
      intervention, designed to alter food perceptions, on both brain responses to food and on food
      intake behaviors in overweight/obese individuals. The investigators hypothesized that this
      bottom-up sensory-level conditioning approach would effectively result in reduced preference
      for high-calorie foods.
    

Detailed description: 
      One factor that may contribute to susceptibility to obesity is a high responsivity to
      high-calorie foods in terms of cognitive factors such as emotional associations, reward value
      or reinforcing properties of food. Many of these processes involve learned associations
      thought to develop via classical conditioning through repeated pairings with external
      stimuli, which can influence food preferences and intake. As such, improving our
      understanding of the neuronal mechanisms underlying these processes and attempting to modify
      them may be a useful strategy to promote weight loss and maintenance. Therefore, the proposed
      study aims to investigate the effects of altering food perception on neuronal responses and
      food intake behaviors by using implicit priming, in which positively or negatively valenced
      images are presented immediately prior to food images, but are not consciously perceived.

      The project goals are to determine the impact of the implicit priming intervention on both
      brain responses to food cues and on food intake behaviors in overweight/obese individuals.
      Food image ratings were assessed before and after either (a) an active implicit priming
      intervention or (b) a control intervention. One group of participants (n = 47; "MRI sample")
      completed the intervention during an fMRI scan and completed a visual food cues task both
      before and after the intervention (during fMRI), to assess intervention-related change in
      neuronal responses to food cues. In this group, food intake measures were also taken
      following fMRI. In a separate group of participants (n = 45; "Behavioral-only sample"), the
      primary outcome measure was the change in food image ratings from pre- to post-intervention;
      fMRI and measures of food intake were not assessed in this group.
    

Intervention name(s): Active Implicit Priming; Control Implicit Priming
Intervention type(s): Behavioral; Behavioral
Intervention description(s): A 10-minute implicit priming intervention, associating food images with images of positive or negative valence.; A 10-minute implicit priming intervention, associating food images with images of neutral valence.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The "MRI sample" and "Behavioral-only sample" involve separate participants who complete the same intervention (assigned to either active or control groups), but the "MRI sample" also completed MRI outcomes and a food intake outcome that the "Behavioral-only sample" did not.
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment