Brain Fingerprinting Upasana M. Bhilota, Dhara J. Patel Department Of Computer Science, Ganpat University, Kherva Mehsana Abstract: Throughout the history of the criminal justice system, numerous technological innovations have signaled landmark changes in how authorities conduct investigations. From fingerprinting to DNA testing, these one-time technological marvels turned police investigation staples have shaped the way that justice is conceptualized in America, as well as the way in which society interacts and is influenced by law enforcement. One such new technology carries with it an emerging potential to revolutionize the investigatory landscape Brain Fingerprinting (BF) the law enforcement technology [1]. Keywords: Techniques, Applications, Limitations, Case Study INTRODUCTION Brain Fingerprinting was developed and patented in 1995 by Lawrence A. Farwell, Ph.D., chairman of the Brain Wave Institute in Fairfield, Iowa, and former Harvard University research associate. Brain fingerprinting is based on the theory that throughout any action, the brain plans, records, and executes all of the actions. Such details, all concealed within the brain, can now be revealed through brain fingerprinting. This technique measures how brain waves respond to specific words or pictures flashed across a screen. Pictures, both relevant and irrelevant to the actions, are shown. The relevant images should trigger memories of subject [2]. It is a scientific technique to determine whether specific information is stored in an individual brain or not. In this technique relevant words, pictures, sounds, videos etc are presented to a subject by a computer in a series with stimuli. Basic fundamental of this technique is whether an individual recognizes specific information related to an event or activity by measuring electrical brain wave responses to words, phrases or pictures presented on computer screen. The technique can be applied only in situations where investigators have a sufficient amount of specific information about an event or activity that would be known only to the perpetrator and Investigator. In this respect, Brain Fingerprinting is considered a type of Guilty Knowledge Test. Existing (polygraph) procedures for assessing the validity of a suspect's "guilty" knowledge rely on measurement of emotion based physiological signals such as palm sweating, heart rate and blood pressure while Brain Fingerprinting measures electrical brain activity via a fitted headband containing special sensors [3]. Technique: The technique uses an electrical signal known as P300 which is emitted from an individual’s brain beginning approximately 300 milliseconds after it is confronted with a stimulus of special significance. The application of this in brain fingerprinting is to detect the P300 as a response to stimuli related to the crime or other investigated situation, e.g., a murder weapon, victim’s face, or knowledge of the internal workings of a terrorist cell Because it is based on EEG signals, the system does not require the subject to issue verbal responses to questions or stimuli. “The P300 (P3) wave is an event related potential (ERP) which can be recorded via electroencephalography (EEG) as a positive deflection in voltage at a latency of roughly 300 ms in the EEG." “The P300 signal is an aggregate recording from many neurons". Go for MERMER, Not Just P300: Dr Lawrence Farwell improvised on the P300 test. He recognized that the P300 is only a subcomponent of a more complicated response called a MERMER, which is elicited when a person recognizes and processes a stimulus that is particularly noteworthy to him/her. The MERMER (Memory and Encoding Related Multifaceted Electroencephalographic Response) includes the P300 and another longer latency, electrically negative subcomponent with a latency of up to two seconds post- stimulus. In other words, a positive wave followed by a negative one. Tests using the MERMER produced no false negatives or positives and no indeterminate [5]. Figure 1. The person undergoing Brain Fingerprinting The person who is going to be tested wears a special headband with electronic sensors that measure the EEG from several locations on the scalp. Electroencephalography: Electroencephalography (EEG) is the measurement of electrical activity produced by the brain as recorded from electrodes placed on the scalp. EEG is collected from tens to hundreds of electrodes positioned on different locations at the surface of the head. EEG signals (in the range of mili-volts) are amplified and digitalized for later processing. Upasana M. Bhilota et al, / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 4 (1) , 2013, 163 - 166 www.ijcsit.com 163