Neuronal and Behavioral Effects of Implicit Priming in Obese Individuals

University of Colorado Denver (CU Denver)

Status: Completed

Conditions: Overweight; Feeding Behavior; Obesity

Treatments: Behavioral: Active Implicit Priming; Behavioral: Control Implicit Priming

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT02347527

P30DK048520 (U.S. NIH Grant/Contract)

13-1786

R21DK102052 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

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.

Full 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.

Enrollment: 92 patients

Sex: All

Ages: 21 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Overweight/obese adults
• Healthy weight adults

Exclusion criteria

• Vegetarian, vegan, or having other wide-ranging food restrictions
• Currently dieting
• MRI exclusion criteria, if in MRI sample (e.g., claustrophobia, metal in the body)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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92 participants in 4 patient groups, including a placebo group

Active Implicit Priming (MRI sample)

Experimental group

Description:

Participants will complete active implicit priming, in which food images are implicitly primed (i.e., below conscious awareness) with images of positive or negative affect. In addition to measures of food image ratings, this group completed a visual food cues scan during fMRI to assess change in neuronal response to food cues. They also completed a measure of food intake post-intervention.

Treatment:

Behavioral: Active Implicit Priming

Control Implicit Priming (MRI sample)

Placebo Comparator group

Description:

Participants will complete a control implicit priming intervention, which matches the active intervention, but with neutral stimuli as primes. In addition to measures of food image ratings, this group completed a visual food cues scan during fMRI to assess change in neuronal response to food cues. They also completed a measure of food intake post-intervention.

Treatment:

Behavioral: Control Implicit Priming

Active Implicit Priming (Behavioral-only sample)

Experimental group

Description:

Participants will complete active implicit priming, in which food images are implicitly primed (i.e., below conscious awareness) with images of positive or negative affect.

Treatment:

Behavioral: Active Implicit Priming

Control Implicit Priming (Behavioral-only sample)

Placebo Comparator group

Description:

Participants will complete a control implicit priming intervention, which matches the active intervention, but with neutral stimuli as primes.

Treatment:

Behavioral: Control Implicit Priming