24-03-2011, 03:08 PM
Presented by:
Dasari Rakesh Yadav
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INTRODUCTION:
Brain Fingerprinting seeks to reveal that memory, by showing the suspect evidence taken from the crime scene. A head band with sensors is placed on the subject. A series of pictures or words is flashed on the screen. The computer records the brain waves produced in response to what the subject sees. The responses are recorded as a wave form. By analyzing the pattern of waves, we can determine if the subject is recognizing what he is seeing.
The key is finding brain prints. "Think of your hand touching a mirror," explains Norseen. "It leaves a fingerprint." BioFusion would reveal the fingerprints of the brain by using mathematical models. "Just like you can find one person in a million through fingerprints," he says, "you can find one thought in a million."5
By this process of BioFusion, (Lockheed Martin, 2000) information is placed in a database, and a composite model of the brain is created. By viewing a brain scan recorded by (functional) magnetic resonance imaging (fMRI) machine, scientists can tell what the person is doing at the time of recording – say reading or writing, or recognise emotions from love to hate. “If this research pans out”, says Norseen, “you can begin to manipulate what someone is thinking even before they know it.” But Norseen says he is ‘agnostic’ on the moral ramifications, that he’s not a mad scientist – just a dedicated one. "The ethics don’t concern me,” he says, “but they should concern someone else.
Determining whether an individual is telling the truth or telling a lie has been a goal of humankind for centuries . Early methods of lie detection—as well as some modern techniques—rely on observations of proposed nonverbal indicators of deception, such as increased perspiration, changing body positions, or subtle facial expressions .
However, there has been an effort to develop and use technology (ie, the standard polygraph and infrared thermal imaging to aid in the identification of deception by measuring changes in sympathetic nervous system responses. Of several techniques that are currently used and several others that are being developed to aid in the detection of deception, the standard polygraph examination is the most reliable (reliability, 80%–90%) and widely used . Although the polygraph test has become the most common method used to detect deception, it has several drawbacks .
These include failure of the examiner to properly prepare the examinee, misinterpretation of physiologic data on the polygraph charts, and subjectivity involved in polygraph testing. One of the major problems with the polygraph test is that it is entirely based on measurement of the sympathetic nervous system response; however, sympathetic nervous system response is not unique to deception and it can occur in other normal emotional states (ie, guilt, excitement, anger).
Functional magnetic resonance (MR) imaging based on blood oxygen level–dependent (BOLD) imaging is a method that is used to measure indirect responses that are tightly coupled with neuronal activity, and it is used to map human brain functions . This technique may enable accurate mapping of the regions of the brain that are involved in higher cortical functions, including cognitive processes such as deception and truth telling. Results of several functional MR imaging studies have shown the prefrontal cortices, parietal lobes, and anterior cingulate are activated during judgment, manipulation of information, and planning of response, including inhibition . These studies did not use standard polygraph techniques or innovations from that field of expertise or a real-life task that would elicit cognitive and emotional responses. The techniques used in these studies varied and included guilty knowledge testing , digit memory testing , card sorting testing , and neuropsychologic evaluations .
Thus, the purpose of our study was to examine the neural correlates during deception and truth telling by using functional MR imaging and an ecologically valid task and to compare these results with the results of a standard polygraph examination.
METHODS :
The relevant situation used in this study was a mock shooting, in which a starter pistol with blank bullets was fired in a testing room in the functional neuroimaging center at Drexel University. Prior to the study, subjects were informed about gun safety and instructed to fire a pistol with blank bullets. None of the subjects reported having any distress or upset feelings. They were asked to wear goggles for eye protection. The functional MR imaging laboratory is a safe environment, and care was taken to not affect other medical projects. This was followed by an interview phase that used the forensic assessment interview technique , in which the subjects were asked about their involvement in the study and basic demographic information was gathered. Functional MR imaging and polygraph testing were performed after the interview.
Of the 11 subjects, five were asked to tell the truth (scenario 2; ie, they were not involved in the relevant situation), and six were asked to deliberately lie (scenario 1; ie, deny their involvement in the relevant situation). We pooled the subjects who were asked to lie; hereafter, they are referred to as guilty subjects. We also pooled the subjects who were asked to tell the truth; hereafter, they are referred to as nonguilty subjects. The subjects were informed that they would be rewarded $25 for correctly following the instructions given by one of the investigators (S.H.F.). For guilty subjects in the lie-only condition (ie, subjects were asked to lie to all questions), the relevant question was a subjective lie, since the shooter declared his or her lie with a "yes" response, which was actually the truth. In nonguilty subjects, subjects who told the truth lied to relevant questions, which they declared with a "yes" response and admitted to a crime they did not commit. Similarly, for guilty subjects in the truth-only condition (ie, subjects were asked to respond truthfully to all questions), the relevant question was a subjective truth, since the shooter declared the truth with a "no" response, which was actually a lie. In nonguilty subjects, the subjective truthful response to relevant questions was "no," since the subjects truthfully denied the act they did not commit.
Everyone’s brain has a complex surface anatomy. The organization of each person’s brain function (e.g. movement, sensation, language) is unique. Because of this, brain surgery may require “mapping” of these important functions to make surgery safer.
The Arthur A. Ward Jr. Professor of Neurological Surgery, is the expert at the University of Washington, specializing in brain mapping for adults with brain tumors and epilepsy.
Resection (removal) of brain tumors, and removal of areas of the brain which are generating seizure activity in medically intractable epilepsy (cortical resections), are delicate operations that often require identification of essential areas of the brain. Neurosurgeons at the University of Washington in Seattle use a technique called Functional Brain Mapping .
Any condition that requires entry into the brain or resection of part of the brain may be aided by functional mapping. This is determined by the proximity of the surgery to areas of the brain that are critical for function. These conditions include surgery for brain tumors of all types and surgery for medically refractory epilepsy.
Motor mapping and sensory mapping can be performed with the patient under general anesthesia, while language mapping requires the patient to be awake during the mapping. For awake mapping, the patient is under anesthesia (asleep) except during the mapping part of the procedure.
