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Ergebnisse 2 Einträge
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An important feature of addiction is the high drug craving that may promote the continuation of consumption. Environmental stimuli classically conditioned to drug-intake have a strong motivational power for addicts and can elicit craving. However, addicts differ in the attitudes towards their own consumption behavior: some are content with drug taking (consonant users) whereas others are discontent (dissonant users). Such differences may be important for clinical practice because the experience of dissonance might enhance the likelihood to consider treatment. This fMRI study investigated in smokers whether these different attitudes influence subjective and neural responses to smoking stimuli. Based on self-characterization, smokers were divided into consonant and dissonant smokers. These two groups were presented smoking stimuli and neutral stimuli. Former studies have suggested differences in the impact of smoking stimuli depending on the temporal stage of the smoking ritual they are associated with. Therefore, we used stimuli associated with the beginning (BEGIN-smoking-stimuli) and stimuli associated with the terminal stage (END-smoking-stimuli) of the smoking ritual as distinct stimulus categories. Stimulus ratings did not differ between both groups. Brain data showed that BEGIN-smoking-stimuli led to enhanced mesolimbic responses (amygdala, hippocampus, insula) in dissonant compared to consonant smokers. In response to END-smoking-stimuli, dissonant smokers showed reduced mesocortical responses (orbitofrontal cortex, subcallosal cortex) compared to consonant smokers. These results suggest that smoking stimuli with a high incentive value (BEGIN-smoking-stimuli) are more appetitive for dissonant than consonant smokers at least on the neural level. To the contrary, smoking stimuli with low incentive value (END-smoking-stimuli) seem to be less appetitive for dissonant smokers than consonant smokers. These differences might be one reason why dissonant smokers experience difficulties in translating their attitudes into an actual behavior change.
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Event-related functional magnetic resonance imaging was applied to identify cortical areas involved in maintaining target information in working memory used for an upcoming grasping action. Participants had to grasp with their thumb and index finger of the dominant right hand three-dimensional objects of different size and orientation. Reaching-to-grasp movements were performed without visual feedback either immediately after object presentation or after a variable delay of 2-12 s. The right inferior parietal cortex demonstrated sustained neural activity throughout the delay, which overlapped with activity observed during encoding of the grasp target. Immediate and delayed grasping activated similar motor-related brain areas and showed no differential activity. The results suggest that the right inferior parietal cortex plays an important functional role in working memory maintenance of grasp-related information. Moreover, our findings confirm the assumption that brain areas engaged in maintaining information are also involved in encoding the same information, and thus extend previous findings on working memory function of the posterior parietal cortex in saccadic behavior to reach-to-grasp movements.
Erkunden
Team
- Vaitl (2)
Eintragsart
Sprache
- Englisch (2)
Thema
- Image Processing, Computer-Assisted
- Adult (2)
- *Attitude (1)
- Behavior, Addictive/*physiopathology/psychology (1)
- Brain Mapping (1)
- Brain/*physiopathology (1)
- Cues (1)
- Female (2)
- Functional Neuroimaging (1)
- Hand Strength/*physiology (1)
- Humans (2)
- Magnetic Resonance Imaging (1)
- Male (2)
- Memory, Short-Term/*physiology (1)
- *Motivation (1)
- Motor Cortex/physiology (1)
- Orientation/physiology (1)
- Oxygen/blood (1)
- Parietal Lobe/*physiology (1)
- Photic Stimulation (1)
- Psychomotor Performance/*physiology (1)
- Smoking/*physiopathology/psychology (1)
- Somatosensory Cortex/physiology (1)
- Space Perception/*physiology (1)
- Supine Position/physiology (1)
- Surveys and Questionnaires (1)
- Visual Cortex/physiology (1)
- Visual Perception/physiology (1)
- Young Adult (1)