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Electro-encephalography or EEG is an electrophysiological monitoring method that measures the amount of electrical activity which is generated by the simultaneous firing of thousands of neurons. EEG’s are measured by placing electrodes just above the brain at the scalp. These electrodes are then attached with elastic caps that are comparable to bathing caps which is how the data will be monitored. Measurements used to determine EEG are done by voltage fluctuations that come as a result of neuron activity within the brain. EEG’s measure these voltage fluctuations and electrical activity over a certain window of time.

Brief History of Electro-encephalography

The Discovery of the EEG came about in 1875 when the physician Richard Calton reported on findings of electrical phenomena occurring within the cerebral hemispheres of animals. By 1890, The Polish physiologist Adolf Beck published an paper on the spontaneous electrical activity in the brain of both rabbits and dogs which found that a series of rhythmic oscillations were altered by light. Beck then proceeded to experiment by planting electrodes on the surface of the brain to monitor for sensory stimulation. Upon monitoring for fluctuating brain activity Beck came to discover brain waves.

The first recorded EEG came in 1912 when a Ukrainian physiologist Vladimir Vladimirovich Pravdich Nemisky published the first animal EEG of a dog. In 1914 experimentally induced seizures were photographed by Napoleon Cybulski and Jelenska-Macieszyna.

The first human EEG was recorded in 1924 by German physiologist/psychiatrist Hans Berger where he built upon the work of Richard Caton and others. Berger also devised the term EEG and from then on the EEG would be a tremendous advancement within the medical field.

When would you use an EEG?

EEG's would be implemented when certain brain disorders are being evaluated. The use of EEGs helps to give validation to different types of disorders. Some of the typical conditions that use EEG's are the following:

• Brain Tumors
• Dementia
• Sleep Disorders (Insomnia)
• Alzheimer's Disease
• Epilepsy

Method of interpreting EEG

When an EEG is being interpreted it is done by a specialized technician who reads over the recording and then sends off the information to the doctor. EEG's appear on the recording as patterns of waves and these waves are considered to be different levels of consciousness.

EEG's monitor brain activity at different consciousness levels which include the following:

• Alpha State: Alpha waves are brainwaves between 8 to 12 Hz and these waves are said to assist with boosting creativity, anxiety, depression and even stress. In essence Alpha Waves help calm the mind.
• Beta State: This brainwaves dominate our normal waking state of consciousness whenever attention is directed towards cognitive tasks and the outside world. Beta waves are recognized as fast brain waves.
• Theta State: Theta Brainwaves are dominate when we are sleeping as well as when we are in a very deep meditative state. Theta waves are associated with increased learning, and memory.
• Delta State: These brainwaves are associated with slow and low frequency waves that are often seen in dreamless sleep.
• Gamma State: Gamma waves are determined to be the fastest brain waves and correspond to the simultaneous processing of information from different brain regions.

The Method to which in an EEG is read is done through different electrode sites which correspond to alphabetic shorthand's which relate to a certain lobe or region of the brain: These areas are typically identified as: F for frontal, Fp for frontopolar, T for temporal, C for central, P for parietal, O for occipital, A for auricular

Applications of EEG to Cognitive Science

EEG's are found to be useful in the following examples of cognitive studies:

Cognitive Development

In the study of cognitive development, the EEG is used to monitor developmental changes in brain-behavior relations. Here EEG's are found to be a cheap means to understand memory performance during infancy to early childhood.

The following are challenges for developmental cognitive EEG Research

• Spatial and Temporal Research
• Application of EEG Electrodes
• EEG-Appropriate Tasks
• Identifying Artifacts
• Sustained Attention

Research Studies that Use EEG

Neuromarketing

Economists use EEG's to monitor consumers brain activity and regions of the brain that are active while consumers are purchasing products or services.

Human Factors

This challenge deals with workplace optimization. Research is used to distinguish between brain processes that correspond to particular personality traits. These processes determine cognitive as well as attention states during interactions between human and machine.

Social Interaction

EEG research is used to understand certain brain processes that occur human speech and actions. A procedure coined as "hyperscanning" is used to record data from several people at one time.

Brain Computer Interfaces

The challenge in this field addresses the need to use EEG in creating interfaces that help those facing paralysis as well as for members of the military for training scenarios where soldiers use advanced exoskeleton technology to help manipulate objects.

Pros and Cons of EEG

Pros of EEG

• EEG is noiseless which leads for better results via auditory stimuli
• EEG has high temporal resolution that can be obtained within milliseconds

Cons of EEG

• EEG's generally have poor spatial resolution
• EEG is really poor when measuring neural activity that occurs at the cortex of the brain
• Can't distinguish between locations within the brain where certain chemical reactions take place