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van CCT (UK)

van CCT (UK)

The effect of nicotine on attention.

- candidate number8122
- NTR NumberNTR2357
- ISRCTNISRCTN wordt niet meer aangevraagd.
- Date ISRCTN created
- date ISRCTN requested
- Date Registered NTR6-jun-2010
- Secondary IDsABR 32831 CCMO
- Public TitleThe effect of nicotine on attention.
- Scientific TitleThe Neurobiological Basis of Disengagement: A Mechanism Implicated in Visuospatial Attention.
- ACRONYMThe neurobiology of disengagement
- hypothesisIt is expected that:
1. Cholinergic agonism by nicotine (Nicorette mint 2mg) will result in a facilitation of disengagement of attention;
2. Cholinergic agonism will not affect bias.
- Healt Condition(s) or Problem(s) studiedAttention, Nicotine
- Inclusion criteriaParticipants must be male and between 18-40 years old.
- Exclusion criteria1. Hypersensitivity to nicotine or other substances in the chewing-gum;
2. Oral infection or pharyngitis;
3. Active oesophagitis;
4. (History of) cardiovascular disease;
5. Liver failure / insufficiency;
6. Kidney failure / insufficiency;
7. Diabetes mellitus;
8. Use of medication.
- mec approval receivedyes
- multicenter trialno
- randomisedyes
- masking/blindingSingle
- controlPlacebo
- groupCrossover
- Type2 or more arms, randomized
- Studytypeintervention
- planned startdate 9-aug-2010
- planned closingdate9-feb-2011
- Target number of participants32
- InterventionsParticipants will be presented two sessions (placebo/nicotine, sessions are separated by at least a week). In each session, before and after nicotine or placebo intake, participants will be assessed with respect to disengagement and bias. Nicotine will be given as Nicorette mint 2mg.
- Primary outcomeIndependent variable: Cholinergic agonism.

In the Visual Spatial Cueing (VSC) paradigm the dependant variables are:
1. The validity effect in ms, specifically, reaction time validly cued targets minus reaction time invalidly cued targets (Both bias and disengagement related);
2. Parietal cue ERP components (EDAN + LDAP ERP components) (Bias related);
3. P1 validly cued target ERP (Bias related);
4. LPD invalidly cued target ERP (Disengagement related).

In the stop task paradigm the dependant variables are:
1. Stop signal reaction time (SSRT) in ms (both bias and disengagement related);
2. N2 stop signal ERP (Disengagement related);
3. LPD stop signal ERP (Disengagement related).

It is expected that facilitated cholinergic neurotransmission by nicotine will result in increased disengagement but will not affect bias.
- Secondary outcomeIndependent (subject) variable: Smoking.
Dependent variables are the same as listed above.

After placebo, nicotine abstinent smokers will have reduced disengagement (as reflected in EEG and behavioural measures) as compared to healthy subjects. No difference is expected with regard to bias.
- TimepointsAt 30 min post nicorette administration, computertasks are performed and EEG is recorded. Total duration of each session (placebo / nicotine) is approximately 4.5 hours.
- Trial web siteN/A
- statusplanned
- Sponsor/Initiator Utrecht University (UU)
- Funding
(Source(s) of Monetary or Material Support)
- PublicationsN/A
- Brief summaryFor the development of better pharmacological treatment of various disorders in which attention and impulsivity are implicated, such as ADHD, it is of crucial importance to acquire more knowledge on their neurobiological basis. Two functional brain mechanisms that are implicated in visual spatial attention are bias and disengagement. Here, bias refers to increased sensory information processing due to the orientation of attention. Disengagement refers to the interruption of that attentional set, making processing of non attended stimuli possible. The dominant theory posits that cholinergic neurotransmission underlies bias, and disengagement rests on noradrenergic neurotransmission. However, results of pharmacological studies are inconsistent. Scrutinizing the results of pharmacological research suggests the opposite of the dominant model. Therefore a new model is proposed which specifically states that bias rests on noradrenergic neurotransmission and that disengagement rests on cholinergic neurotransmission. Recently we started a University Medical Center (UMC) Utrecht METC (IRB) approved study aimed at testing the noradrenergic part of the model using Clonidine. In the current study, our aim is to test the second cholinergic - part of the model. Since behavioral outcome reflects activity in both, disengagement and bias related mechanisms, studying brain activity is crucial. Therefore we incorporate EEG in combination with two computer tasks to investigate bias and disengagement associated brain indices (i.e., event-related potentials; ERPs). Firstly, we expect that cholinergic agonism by Nicorette mint (2mg) improves disengagement in two samples, smokers and non-smokers. Secondly we expect that nicotine abstinent smokers may have disengagement related dysfunction. Hypotheses will be tested in two samples, smokers and non-smokers. Participants will be presented two sessions (placebo/nicotine, sessions are separated by at least a week). In each session, before and after nicotine or placebo intake, participants will be assessed with respect to disengagement and bias. The burden and risks associated with the tasks and pharmacological manipulation are expected to be negligible.
- Main changes (audit trail)
- RECORD6-jun-2010 - 6-feb-2011

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