Neuroimaging Decision Making and Response Inhibition During Smoking Abstinence

Duke University62 enrolled

Overview

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.

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).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Smoking

Eligibility

Sex: ALLMin age: 18 YearsMax age: 50 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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

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.

Time frame: 12.5 minutes of fMRI scanning following smoking as usual

Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Right Inferior Frontal Cortex (rIFC) During Task on Abstinent Day

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.

Time frame: 12.5 minutes of fMRI scanning following 24 hrs smoking abstinence

Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Presupplementary Motor Area (Pre-SMA) During Task on Abstinent Day

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.

Time frame: 12.5 minutes of fMRI scanning following 24 hrs smoking abstinence

Signal Change in fMRI BOLD Signal Between Response Inhibition Trials and Control Trials in Presupplementary Motor Area (Pre-SMA) During Task on Satiated Day

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.