Brain-wave scanners
Brain-wave scanners are advanced instruments designed to map brain activity and measure responses to various stimuli. They play a significant role in fields such as forensic science and medical research, particularly in lie detection and postmortem brain analysis. Utilizing technologies like functional magnetic resonance imaging (fMRI), these scanners produce three-dimensional images that reflect brain activity patterns, which can indicate whether a person is being truthful or deceptive.
When a subject is questioned, the brain requires more energy to fabricate a lie compared to telling the truth, which is visually represented as increased activity in specific areas of the brain. This method has shown promising accuracy rates exceeding 90% in controlled studies. However, challenges remain for practical applications due to factors like cost, participant consent, and the need for further validation in real-world scenarios.
In addition to lie detection, brain-wave scanners have potential uses in assessing criminal suspects, evaluating intentions of prisoners, and identifying individuals with knowledge of terrorist activities. Ethical considerations, especially regarding privacy, are crucial in discussions about their implementation. For postmortem examinations, techniques like postmortem multislice computed tomography (PMSCT) offer detailed imaging to investigate causes of death, such as head trauma or conditions like shaken baby syndrome.
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Brain-wave scanners
Definition: Instruments used to map regions of the brain or to measure brain responses to stimuli.
Significance: Brain-wave scanners can be used to monitor brain activity to determine whether or not a person is telling the truth and to perform postmortem mapping of the brain to determine whether death may have resulted from trauma to the head.
Brain-wave scanners are used to map activity in the brain. The patterns seen in the three-dimensional images produced by brain-wave scanning are indicative of whether or not a person is lying. The images are formed using magnetic resonance imaging (MRI). When experts examine the images to determine which areas of a person’s brain become active in response to questions, pictures, or other stimuli, this method is referred to as functional magnetic resonance imaging (fMRI). The subject is placed inside the scanning machine and allowed to interact with a computer screen to answer specific questions related to a crime. The MRI machine is interfaced with special computer software that recognizes specific brain patterns. When a person is telling a lie, the brain has to expend more energy than it does when the person is telling the truth. Even when a lie has been rehearsed in the mind of the subject, the subject uses more brain energy to think beyond the truth and access the lie. The extra brain activity shows up as a “bright” region on the brain-scanned image. In tested case studies, the fMRI method has shown an accuracy of more than 90 percent in detecting lies.
Although still undergoing development and refinement, the fMRI technique has many possible forensic applications. These include situations that involve libel, slander, fraud, or terrorist activities; the technology may also be useful in the security screening of potential employees for important government positions. The technique might be used in the interrogation of criminal suspects or in the assessment of the intentions of prisoners before they are released. Because individuals involved in terrorist plots have detailed knowledge of plans and activities that innocent persons do not have, brain scans might be used to identify persons who have terrorist training and knowledge of terrorist activities.
The primary ethical issue that needs to be addressed in regard to the use of brain-wave scanners as lie detectors is that of the invasion of personal privacy. This problem may be resolved by safeguards that ensure that subjects are fully informed about brain-wave scanning and agree to be examined in this way.
For examination of the brain after death, postmortem multislice computed tomography (PMSCT) provides detailed in situ images of the brain. These are useful for screening corpses for foreign matter in the brain or for identifying whether head trauma resulting in skull fractures or cerebral hemorrhaging was the cause of death. Both two-dimensional cross-sectional images and postprocessed three-dimensional images of the skull can be made. Postmortem computed tomographic (PMCT) scans of an infant’s brain can reveal signs that are indicative of shaken baby syndrome. This type of child abuse is accompanied by subdural hemorrhage of ruptured cerebral bridging veins, which can be identified in PMCT images but is difficult, if not impossible, to detect in a typical autopsy.
Bibliography
Saferstein, Richard. Criminalistics: An Introduction to Forensic Science. 9th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2007.
Tilstone, William J., Kathleen A. Savage, and Leigh A. Clark. Forensic Science: An Encyclopedia of History, Methods, and Techniques. Santa Barbara, Calif.: ABC-CLIO, 2006.
White, Peter, ed. Crime Scene to Court: The Essentials of Forensic Science. 2d ed. Cambridge, England: Royal Society of Chemistry, 2004.