An fMRI Study of Self-regulation in Adolescents With Bulimia Nervosa

This study will use magnetic resonance imaging (MRI) to assess the structure (cortical thickness) of neural circuit regions involved in Bulimia Nervosa (BN).

The Conners Continuous Performance Test-II (CPT-II) is a standardized measure of attention and impulsivity. The following variables (T-scores) were used:

Omissions: the number of times the participant failed to respond to a target. High T-score indicates a worse outcome.

Commissions: the number of times the participant responded but no target was presented. High T-score indicates a worse outcome.

Hit Reaction Time: time between the presentation of the stimulus and participant's response. A fast reaction time (low T-score) and high commission errors points to difficulties with impulsivity. A slow reaction time (high T-score) with high commission and omission errors, indicates inattention in general.

Hit Reaction Time Standard Error: levels of inconsistency in response speed. High T-score indicates a worse outcome.

Detectability: discrimination for target and nontarget. High T-score indicates a worse outcome.

Population mean (standard deviation) = 50 (10)

The Stroop Word-Color Interference Test is a neuropsychological test assessing the ability to inhibit cognitive interference.

The test contains three parts: word page (the names of colors printed in black ink), color page (rows of X's printed in colored ink) and word-color page (the words from the first page are printed in the colors from the second page; however, the word meanings and ink colors are mismatched).The subject's task is to look at each sheet and move down the columns, reading words or naming the ink colors as quickly as possible, within a given time limit (45 seconds). Three scores, as well as an interference score, are generated using the number of items completed on each page, with higher scores reflecting better performance and less interference on reading ability. Scores range 0-100.

The Weather Prediction Task is a measure of probabilistic learning using experimental analysis of weather prediction. In this task, participants try to predict either "rain" or "shine" based on the presentation of cards whose cue-outcome associations vary probabilistically. Accuracy score (i.e. percentage of correct response) was used in our analyses. A higher score indicates better outcome. Values range 0-100%, with 50% being chance level.