Parahippocampal activation reveals countermeasure use in a sentence-based complex trial protocol guilty knowledge...

Area of Science:

• Cognitive Neuroscience
• Forensic Psychology
• Neuroscience

Background:

• The Guilty Knowledge Test (GKT) is a psychophysiological method for detecting concealed information.
• The Complex Trial Protocol (CTP) is a variant of the GKT designed to enhance detection accuracy.
• Investigating the impact of countermeasures on CTP performance is crucial for its real-world application.

Purpose of the Study:

• To evaluate the efficacy of the Complex Trial Protocol (CTP) in detecting guilty knowledge using Korean sentence stimuli.
• To examine the influence of countermeasures on event-related potentials (ERPs) during guilty knowledge detection.
• To explore the neural sources of ERP modulations associated with countermeasures.

Main Methods:

• Employed a mock crime paradigm with three groups: simple guilty (SG), countermeasure (CM), and innocent (IN).
• Utilized Korean sentences in a subject-object-verb format, embedding crime-relevant information in the object.
• Analyzed event-related potentials (ERPs) and employed standardized low-resolution electromagnetic tomography (sLORETA) for source localization.

Main Results:

• Late positive activity (P900) was observed around 900 ms for probe verbs in both SG and CM groups.
• Significant parahippocampal activation was detected exclusively in the CM group via sLORETA.
• Findings suggest P900 in the CM group might reflect memory modulation strategies to suppress recognition.

Conclusions:

• The CTP is effective for guilty knowledge detection.
• Sentence complexity and countermeasure strategies modulate the expression and neural origins of late ERP components.
• Parahippocampal activation in the CM group suggests active cognitive strategies influencing recognition memory.