Neuroimaging Decision Making and Response Inhibition During Smoking Abstinence

Not Applicable

Completed

Conditions: Smoking

Interventions: Behavioral: Smoking Abstinence

Registration Number: NCT00672256

Lead Sponsor: Duke University

Brief Summary: The broad objective of this proposal is to identify functional neuroanatomical correlates of impairments in response inhibition during smoking abstinence. We will measure changes in performance and regional blood oxygenation levels using functional magnetic resonance imaging (fMRI)while smokers complete tasks designed to assess decision making and response inhibition.

Our primary hypothesis is that smoking abstinence will result in impaired response inhibition accompanied by decreases in blood-oxygenation-level-dependent (BOLD) fMRI signal in brain regions associated with these cognitive processes including frontal cortex and the ventral striatum. Abstinence may also result in performance-related increases in activation in brain regions associated with effortful processing including the anterior cingulate cortex in effort to compensate for deficits in other regions.

Detailed Description: Participants will learn and practice a Go/No-Go reaction time task (Garavan, Hester, Murphy, Fassbender, \& Kelly, 2006) that measures inhibitory and excitatory aspects of behavioral control. During the task subjects are presented with an alternating series of Xs and Ys in the center of the screen and must press a button every time they see a Go trial (the letter 'Y' or the letter 'X') while inhibiting a response when they are presented with a No-Go trial (any interruption of the X Y alternating stream, e.g., X Y Y).

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 62

Inclusion Criteria

Smoker subjects must have

smoked an average of 10 cigarettes per day for two continuous years of a brand that delivers (by Federal Trade Commission rated yields) at least 0.5 mg nicotine
have an expired air carbon monoxide reading of at least 10 ppm.
must be in general good health

Non-smoker subjects must have

smoked less than 50 cigarettes in their lifetime
have not smoked in the last six months
have an expired air carbon monoxide reading of less than or equal to 5 ppm.
must be in general good health.

Exclusion Criteria

major medical condition
anything that would make participation unsafe (e.g., have pacemaker or other metallic implant) or uncomfortable (e.g., chronic pain)
psychiatric condition
suffering from claustrophobia
current alcohol or drug abuse
smokeless tobacco use, or use of nicotine replacement therapy or other smoking cessation treatment

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Smokers not interested in quitting smoking	Smoking Abstinence	Smokers were scanned 24 hours after quitting smoking, and scanned after smoking as usual.

Primary Outcome Measures

Name	Time	Method
Signal Change in Functional Magnetic Resonance Imaging (fMRI) BOLD Signal Between Response Inhibition Trials and Control Trials in Right Inferior Frontal Cortex (rIFC) During Task on Satiated Day	12.5 minutes of fMRI scanning following smoking as usual	Percent signal change in fMRI BOLD response in rIFC to correctly inhibited targets (as compared to control trials) during a response inhibition task following smoking as usual. Response inhibition trials are trials in the task in which the participant must inhibit a response (not press the button)when presented with a No-Go trial. Control trials are trials in the task in which the participant must press the button when presented with a Go trial.
Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Presupplementary Motor Area (Pre-SMA) During Task on Abstinent Day	12.5 minutes of fMRI scanning following 24 hrs smoking abstinence	Percent signal change in fMRI BOLD response in pre-SMA to correctly inhibited targets (as compared to control trials) during a response inhibition task following not smoking for 24 hours. Response inhibition trials are trials in the task in which the participant must inhibit a response (not press the button)when presented with a No-Go trial. Control trials are trials in the task in which the participant must press the button when presented with a Go trial.
Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Right Inferior Frontal Cortex (rIFC) During Task on Abstinent Day	12.5 minutes of fMRI scanning following 24 hrs smoking abstinence	Percent signal change in fMRI BOLD response in rIFC to correctly inhibited targets (as compared to control trials) during a response inhibition task following not smoking for 24 hours. Response inhibition trials are trials in the task in which the participant must inhibit a response (not press the button)when presented with a No-Go trial. Control trials are trials in the task in which the participant must press the button when presented with a Go trial.
Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Presupplementary Motor Area (Pre-SMA) During Task on Satiated Day	12.5 minutes of fMRI scanning following smoking as usual	Percent signal change in fMRI BOLD response in pre-SMA to correctly inhibited targets (as compared to control trials) during a response inhibition task following smoking as usual. Response inhibition trials are trials in the task in which the participant must inhibit a response (not press the button)when presented with a No-Go trial. Control trials are trials in the task in which the participant must press the button when presented with a Go trial.