Crime Scene Investigation
Brain Mapping: A Neurological Technique

Brain Mapping: A Neurological Technique

Brain mapping is basically a process that measures and studies the changes in the electrical field of potentials produced by the sum of the neuronal activities in the brain of an individual person. It is a concept of neuroscience which uses a set of neuroscientific techniques to map the various brain activities through electrical signals. 

The human brain is an epicenter for all thought processes and is responsible for the control and coordination of the body. It is the brain of an individual which directs him/her to do any act consciously, subconsciously, or unconsciously.

The brain controls voluntary movements, the balance of the body, vital functions of the involuntary organs, thermoregulation, and other rhythms of the body. All the processing of senses, thoughts, and emotions is conducted by the brain. 

Parts of the Human Brain

The brain is a complex organ that regulates and monitors the overall functioning of the human body. The human brain is enclosed in the bony skull. Inside the skull, the brain is covered by cranial meninges which consist of an outer layer, the dura mater, a middle thin layer called arachnoid, and an inner layer namely the pia mater. Broadly, the human brain is divided into the following:

  • Forebrain

Forebrain handles memory, intelligence, and reasoning. It is also responsible for perceiving pain, sound, smell, taste, and touch. The further classification of the forebrain contains the cerebrum, thalamus, and hypothalamus. Cerebrum contains the maximum number of neurons and is responsible for memory. Thalamus is the major coordinating center for sensory and motor signaling. Hypothalamus controls the pituitary gland and controls the temperature, urge of drinking and eat, etc.

  • Midbrain

Midbrain is responsible for the coordination of muscular activities of the body. It is located between the thalamus and the hypothalamus.

  • Hindbrain

Hindbrain controls the activity of vital internal organs. It is further divided into pons, cerebellum, and medulla oblongata. Pons connect different regions of the brain. Cerebellum provides extra space for more neurons. Medulla oblongata connects the brain to the spinal cord and regulates the processes of respiration, gastric secretions, and cardiovascular reflexes.

The other important organ which is involved in the control and coordination of the human body is the spinal cord. It is the site of origin for all the nerves that are extended all over the body.

How the Brain Mapping Evolved?

Brain mapping involves the study of the structural anatomy & neuro sensory functioning of the brain & the spinal cord associated with the brain’s sensory nerves & their receptors by using interoperative, non-invasive imaging, and cellular biology, including the various aspects of engineering sciences related to the Material science, Electrical & Biomedical functioning of the neurons. 

The Society for Brain Mapping and Therapeutics in 2013 defined brain mapping as the study of the anatomy and function of the brain and spinal cord through the use of imaging, immunohistochemistry, molecular & optogenetics, stem cell and cellular biology, engineering, neurophysiology, and nanotechnology.  

Brain mapping was developed and patented in 1995 by neurologist Dr. Lawrence A. Farwell, Director, and Chief Scientist of “Brain Wave Science”, IOWA. 

The Forensic Science Laboratory in Bangalore is the first centre in India that conducts the Brain-mapping or Brain-fingerprinting test.

Techniques and Instruments Used in Brain Mapping

Brain mapping is a consolidated set of neuroscientific techniques that are used to collect brain images and analyze them. Several techniques used for brain mapping are:-

  • Computer Axial Tomography (CAT) Scan

X-ray images of the brain are collected from different angles.

  • Structural magnetic resonance imaging

The images of the brain are collected with the help of water in the brain, which has a better resolution than CAT.

  • Diffusion Tensor-MRI (DTI)

In this technique, the imaging of the neurons is done which acts as a connecting link between brain regions by following the movements of water in the brain.

  • Electroencephalography (EEG)

This instrument measures the electrical activity of the brain.

  • Positron emission tomography (PET)

The presence of radioactive markers in the brain can be tracked by this technique.

  • Functional MRI (fMRI)

When the subject carries out different functions, then this technique is used to trace the brain activity.

  • Pharmacological Functional MRI (phMRI)

This MRI technique is used to examine the activities of the brain after the subject administers a drug.

  • Transcranial Magnetic Stimulation (TMS)

This technique is useful to observe the activities of the brain when different regions of the brain are triggered with various simulations that result in particular behavioral responses. 

Computer Axial Tomography (CAT) Scan, Structural magnetic resonance imaging, and Diffusion Tensor-MRI (DTI) are the techniques that collect brain images. And the remaining above-mentioned techniques are used to examine the brain images.

Principle of Brain Mapping

The brain consists of the structural and functional units as the Neurons. These neurons are responsible for transferring messages between the brain and the various organs. These messages are in the form of electrical signals which can be captured in the form of waves on a brain map. The brain map is able to capture a window of brain activity, analyze the data, and create a visual representation of each lobe of the brain and each specific brain wave. There are usually four types of brain waves produced:

  • Alpha waves

These waves are produced when the brain is in a relaxed and reflective mode.

  • Beta waves

When the brain is active and working, then it produces beta waves.

  • Delta waves

Delta waves show that the brain is dreaming or in sleeping mode.

  • Theta waves 

These waves are produced when the brain is drowsy and in a meditative mode.

Another point that is useful in forensics is that brain mapping is based on the finding that the brain generates a unique brain-wave pattern when a person encounters a familiar stimulus.

How is Brain Mapping Conducted?

Brain mapping is also called the P300 Waves Test or Brain Electrical Activation Profile test. P300 or P3 is an event-related potential (ERP) component elicited in the process of decision-making. This potential is produced only when the subject recognizes any stimulus. It has a peak literacy of about 300 to 800 milliseconds at the midline partial area of the head.

In this test, the subject is made to sit in an evoked potential recording machine and a number of sensors are placed on different regions of the subject’s head. The subject is exposed to auditory or visual stimuli that are relevant to the facts being investigated alongside other irrelevant words and pictures, which can be named as ‘material probes’ or irrelevant probes’.

The sensors on the head of the subject monitor electrical activity in the brain and register P300 waves, which are generated only if the subject has a connection with the stimulus i.e. picture or sound. No questions are asked of the subject throughout the process, unlike the Polygraph test

Dr. Farwell in his work has published that a MERMER (Memory and Encoding Related Multifaceted ElectroEncephalographic Response) is initiated in the accused when his brain recognizes noteworthy information pertaining to the crime. He was able to test the p-300 and also a negative electrical component which is found at the midline frontal area and has an asset latency of 800 to 1200 milliseconds through MERMER.

However, when Dr. Farwell patented the brain mapping machine the keywords, phrases, or pictures collected and related to the crime were mixed with irrelevant words and pictures and flashed on the screen and the subject was asked to press the correct option. But sometimes the subject pressed the wrong button which created problems in the test.

To overcome this problem Dr. Mukundan of Brainex (Brain Experience) Company in Bangalore designed a special software called “Brain Electrical Activation Fingerprinting” which is said to be a modified version of Dr. Farewell’s techniques. In this technique, the entire crime scene is created and shown to the suspect and the reactions of the suspect are recorded. However, this is not possible with mentally ill people or habitual criminals. 

Application of Brain Mapping in Forensics

The human brain is like a recording box that stores all the information that is perceived by the sense organs. There is an instinctive ability in the brain to identify persons, places, objects, etc., and is kept reserved in memory.

Brain mapping is used to determine whether certain information is or is not present in the brain of a person. When the person encounters the same stimuli again there is a rush of electrical signals in the brain. These electrical signals are received by the EEG which are shown in the form of waves in the brain map. The electrical rush of P300 is only observed when the person remembers the stimulus otherwise no signal is produced.

Brain mapping is a boon for investigating agencies, especially when they encounter any organized crime or where there is no evidence found. When a person commits a crime, all the events are stored in his/her brain which cannot be vanished. He/she may try to deceive the investigators with fake statements but his/her brain cannot deceive.

Brain mapping detects the presence of crime. The perpetrator when subjected to brain mapping, it actually detects the information related to the crime committed by him/her being stored in his/her brain.

However, this test only ensures that the subject is present at the place of occurrence, it does not ensure that the person concerned has committed that crime. He may be present at that place for any other purpose.

Laws Related to Brain Mapping in India

Although brain mapping is a boon to the investigating agencies and has 100% positivity still it is not acceptable in the courts of India. In 2010, the Supreme court of India declared the use of the polygraph, narco analysis, and brain mapping on the suspects as illegal if the examinee does not give consent.

In fact, it is mentioned in Article 20(3) of the Indian Constitution, which states that, “No person accused of any offense shall be compelled to be a witness against himself”. The court has considered the compulsory use of drugs and brain mapping unconstitutional. The court, however, permitted the use of such techniques in criminal cases on consent and with some safeguards


Brain mapping is one of the Deception Detection Techniques(DDT) which is based on the information stored in the brain of an individual. It is a technique in which the subject is not asked any questions during the test. He is only directed to audio or visual stimuli related to the crime.

The important factor of this technique is the P300 electrical wave which is released only when the subject has a memory of the stimuli provided. 

It is a technique with 100% positivity still it is not admissible in the Courts as it violates the rights mentioned in Article 20(3) of the Indian constitution. However, The 2010 Supreme Court judgment on DDT is admirable from the scientific, human rights, ethical, legal, and constitutional perspectives.

Also Have a Look at:

Leave a Reply

Your email address will not be published. Required fields are marked *