Ihre Suche
Ergebnisse 2 Einträge
-
There is some evidence that neuroimaging can be used to predict relapse among abstinent methamphetamine-dependent (MD) individuals. However, it remains unclear what cognitive and neural processes contribute to relapse. This investigation examined whether insula activation during risk-taking decisions-a process shown to be disrupted in MD-is able to predict susceptibility for relapse. Sixty-eight MD enrolled in a treatment program during early abstinence completed a risk-taking task during functional magnetic resonance imaging. Sixty-three of the sixty-eight individuals were followed up 1 year after the study. Of these, 18 MD reported relapse. The 45 abstinent MD showed patterns of insula activation during risky decisions that resembled those found in prior studies of healthy controls, consisting of lower insula activation during safe decisions paired with higher activation during risky decisions. In contrast, the 18 relapsed MD showed similar insula activation during safe and risky decisions. An increase in one standard deviation in the difference in insula activation between risky and safe choices was associated with a 0.34 odds ratio for relapse at any given time. A median split of insula activation (difference between risky and safe) showed that individuals in the bottom half were two times more likely to relapse. In addition, a model that included several other brain regions increased prediction accuracy compared with insula-based model alone. These results suggest that failure to differentially activate the insula as a function of risk is a part of an altered risk-processing network associated with an increased susceptibility to relapse.
-
The Concealed Information Test (CIT) requires the examinee to deceptively deny recognition of known stimuli and to truthfully deny recognition of unknown stimuli. Because deception and orienting are typically coupled, it is unclear how exactly these sub-processes affect the physiological responses measured in the CIT. The present study aimed at separating the effects of deception from those of orienting. In a mock-crime study, using a modified CIT, thirty-six of seventy-two subjects answered truthfully ('truth group'), whereas the other thirty-six concealed their knowledge ('lie group'). Answering was delayed for 4 s after item presentation. Electrodermal activity (EDA), respiration (RLL), and phasic heart rate (HR) were recorded. A decomposition of EDA responses revealed two response components; the response in the first interval was expected to indicate orienting, stimulus evaluation, and answer preparation, whereas the response in the second interval was assumed to reflect answer-related processes. Inconclusively, both EDA components differentiated between 'probe' and 'irrelevant' items in both groups. Phasic HR and RLL differed between item classes only in the 'lie' group, thus reflecting answer-related processes, possibly deception, rather than merely orienting responses. The findings further support the notion that psychophysiological measures elicited by a modified CIT may reflect different mental processes involved in orienting and deception.
Erkunden
Eintragsart
Sprache
- Englisch (2)
Thema
- ROC Curve
- Adult (2)
- Amphetamine-Related Disorders/*diagnosis/*physiopathology (1)
- Behavior/physiology (1)
- Brain Mapping (1)
- Cerebral Cortex/*physiopathology (1)
- Crime/psychology (1)
- Data Interpretation, Statistical (1)
- Decision Making/*physiology (1)
- Electrocardiography (1)
- Female (2)
- Fingers/blood supply (1)
- Follow-Up Studies (1)
- Galvanic Skin Response/physiology (1)
- Heart Rate/physiology (1)
- Humans (2)
- Lie Detection/*psychology (1)
- Magnetic Resonance Imaging (1)
- Male (2)
- Methamphetamine (1)
- Neuropsychological Tests (1)
- Plethysmography (1)
- Prognosis (1)
- Proportional Hazards Models (1)
- Reaction Time/physiology (1)
- Recurrence (1)
- Regional Blood Flow/physiology (1)
- Regression Analysis (1)
- Respiratory Mechanics/physiology (1)
- *Risk-Taking (1)
- Survival Analysis (1)
- Young Adult (1)