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Frontoparietal activity during deceptive responses in the P300-based guilty knowledge test: an sLORETA study
Eun Kyung Jung1, Ki-Young Kang, Young Youn Kim
1Department of Forensic Psychology, Kyonggi University, Suwon, South Korea.
Neuroimage
|April 23, 2013
Summary
Guilty individuals show distinct brain activity during a P300-based guilty knowledge test (GKT). Their brains exhibit heightened P300 amplitude and frontal activation when processing crime-relevant information, unlike innocent individuals.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Forensic Science
Background:
- The P300 event-related potential (ERP) is a valuable tool in cognitive neuroscience.
- The Guilty Knowledge Test (GKT) utilizes P300 detection to identify concealed information.
- Investigating the neural underpinnings of GKT responses enhances its validity and application.
Purpose of the Study:
- To investigate the cortical source activity during a P300-based GKT using Korean sentences.
- To differentiate brain responses between guilty and innocent individuals processing crime-relevant stimuli.
- To explore the cognitive mechanisms underlying GKT performance.
Main Methods:
- Thirty male students participated in simulated guilty or innocent scenarios.
- Electroencephalogram (EEG) was recorded during a visual P300-based GKT.
- Stimuli included target, probe (crime-relevant), and irrelevant sentences.
- Standardized low-resolution electromagnetic tomography (sLORETA) analyzed cortical source activity.
Main Results:
- A significant difference in P300 amplitude was observed between guilty and innocent groups.
- Guilty subjects showed increased P300 amplitude in the frontoparietal region for probe stimuli.
- sLORETA revealed significant activation increases in the guilty group for probe stimuli, particularly in frontal and parietal regions.
Conclusions:
- Guilty and innocent individuals exhibit different cognitive processing of crime-relevant sentences during GKT.
- Frontal activation in guilty subjects may indicate working memory, memory retrieval, and inhibition.
- Parietal activation suggests selective attention and target discrimination in processing sentence elements.

