What is the History of EEG waves and Neuro imaging techniques

Brain Wave Decoder
EEG Waves

This is the complete step by step guide of Brain wave decoder project.We will cover each and every step with details and practical results.There are three main parts of the project The hardware,circuit designing and the software.In the hardware section we will discuss about EEG project applications,The selection of electrodes for capturing EEG waves. The circuit designing part consists of designing filters for extracting EEG waves.The last part is about test results and real time EEG wave simulations. The brain wave controlling EEG project consists of many sub sections.The complete project will be covered in the following posts.

  1. Brain wave decoder EEG project step by step guide
  2. What is EEG and How it works
  3. What is the History of EEG waves and Neuro imaging techniques
  4. Brain computer interface BCI monitoring systems
  5. Functionality and Applications of the brain wave EEG project
  6. Material required for portable EEG system development
  7. How to select electrodes for brain wave EEG project
  8. circuit designing steps for EEG portable monitoring device
  9. How to design filters for EEG circuit
  10. Schematic diagrams of brain wave EEG project
  11. Simulation analysis of brain wave controlling EEG project
  12. Challenges and Problems in EEG brain wave controlling project
  13. Final results of brain wave decoder EEG project
  14. How to filter EEG waves on MATLAB
  15. Future research for EEG project
  16. Hardware and software list for EEG project



The techniques used for measuring signal from brain have different methods. The EEG is one of them. The term is used for the activity of the signal in the brain. The signal measured using electrodes placed on the human scalp that sends direct current signal from brain to the EEG circuit. The EEG circuit passed through different steps of processing to make the EEG signal readable. As the brain have different regions and every region have its unique response. In our project the main region of connecting electrodes is the frontal lobe of the brain.

For getting EEG data recoded there are three electrodes used. In these three electrodes the one is the positive and other is the negative to get the differential from brain. The third electrode is the ground electrode. The negative is on the left of the frontal lobe,  positive on the right  of frontal lobe and ground electrode will be placed on the mastoid position behind the ear. These three electrodes connected on the scalp treats the human brain as a circuit. When we focus or move head, arm and eyes the circuit responds. The brainwave signals occur at a frequency around 1-30Hz. The EEG signal needs to be filtered and amplified then it will be used to perform any application.

EEG History

Hans Berger in 1929 was the first person who introduced the EEG.  Hans Berger was a neuropsychiatrist. He belongs to the Germany the University of Jena. He defines different changing states of the brain. At his time the Hans Berger ideas has importance and has importance as a new theory. After that the studies started on these theories.

At that time the researcher and scientists did not believe on Berger’s theories and conclusions. Later on Edgar Douglas Adrian was a scientist who proves  the theories of Hans and  then another scientist B. C. H. Matthews also proves his conclusions. After the verification of the theories the scientists started studying this field and started experiments. In 1936, W. Gray Walter demonstrated about brain tumor and this technology. Walter used different and small electrodes to find the brain tumor caused areas of the brain.
Over the years there is massive advancement have seen in the development of EEG systems and electrodes, amplifiers, and other BCI devices. Different electrical maps of the brain have been created. Scientist identifies every part every region of the brain and how it responds. In the year 1957, Walter developed a device. The device called the topo scope. This device is used for brain’s surface layout and mapping of it. This device shows activity of the brain in different brain section areas. These devices were made but could not achieved commercial success because of expensive and complex in nature. The EEG system come up with more electrode channels to measure brain activity with accuracy. Our system is based upon 3 channel EEG recording. There are 14 to 40 electrode channels available.

Neuro imaging approaches

The brain computer interface systems(BCI) use human brain signal and gather the required information and attention. For recording brain activity there are two main parts, the acquisition part and the translation part. The acquisition part involves the signal processing and the translation part involves the signal translation. There are different types of monitoring brain activity. But these two are the basic methods.

  1. Electrophysiological
  2. Hemo-dynamic.

The brain signals are generated in the brain through the reaction of exchanging information of neurons. The current of ions is generated across the neuronal assemblies when neurons communicate with each other. The extracellular current flows enclosed the primary current which is known as the secondary current type.

The brain systems obtain the desired and most required information from EEG. EEG is mostly used for current system of extracting brain signal information. It has high resolution and easy to use. It also has no systemic and other issues. The method is mostly used in different medical and control and communication applications. The BCI systems consists of different EEG monitoring or capturing electrodes to gather the information from different areas of brain. The quality of electroencephalography(EEG) signals has different aspects. There are different areas where the EEG signal affected. It arises with different layers and noise. The most prominent damage to the EEG signal is the line noise. Noise is the main issue in these systems. There are different techniques adopted for removing and maintain the quality of signal.

There are two main approaches for EEG signal recording. One is the invasive and the other is noninvasive. The most advance approach is Noninvasive. These are used for many medical application and monitoring systems. These are used partially for patients to use. In theapplications of the system these are used for communication and for the purpose of control prosthetics, wheelchair and limbs. In non-invasive approaches in BCI systems there are many limitations. There are also some limitations because of the low resolution of the brain signal. These methods were introduced for solving the issues in these systems.The movement restoration through prosthetics limbs can be achieved by these approaches in BCI’s. In future the noninvasive approaches may use for control and communication and for the improvement and the better quality of brain signal. More and further improvements are needed for more and better quality of the systems and signals.

The research shows these techniques have advantages in medical and most in control applications. And the demand and quality of the systems increases every day as the studies goes on.

In some Invasive techniques there is a complex method used. In these cases, the system needs human brain surgery to place electrodes inside. Due to its complexity and involving of brain surgery there is a high risk involves. There are more other problems and issues involves in the overall process. First is the tissue acceptance of the microelectrode. The Nano technology approach may be used in these to overcome the problems and issues. This somehow is most important factor. If the electrodes placed inside the brain using Nano technology, it has a wireless connection for reducing the risk of infection and damage. All the different methods have been tested before on animals for safety reasons. The stress and movement of humans can be caused to damage the brain in the process.

Existing Brain Signal Monitoring Systems

BCI, the brain computer interface can be performed at the vicinity of neurons inside the brain cortex, over the human scalp. The invasive techniques require complex systems and clinically brain surgery. There are limitations in these systems.  It can only be used in most critical and clinical needs. The second method is the non-invasive. This procedure can be performed generally without any complex and medical complicacy.

The invasive and noninvasive techniques have different methodologies. There are advantages and disadvantages of the systems with respect to their technique.

Challenges of BCI Systems

There are many issues in different techniques of measuring brain activity. The invasive and noninvasive techniques for measuring brain activity. The electrodes used in invasive nature of ECoG and MEA raised a lot issues and medical challenges. There is more precision of the subject needed in this technology like pre-surgically and proper evaluation. The accuracy and cortical position depends on the technology used.

There are many issues like Neurotrophic and neural brain damage faced by many scientist and students like us in using non-dry electrodes that requires surgery for brain monitoring.

These two main techniques for measuring and monitoring brain activity.

  1. Invasive
  2. Non-invasive

Invasive BCI Monitoring Technologies

The intracranial cortical medical neuronal devices are highly invasive. These implantable medical devices required to attach to the outside or inside using dry electrode or surgery method of electrode placement of the skull containing electronic signal processing circuitry that is connected to one or more or the complex cap of electrodes that penetrates the skull to monitor and to record neural activities in the brain. Multiple Electrode Array (MEA) used as to record the neural activity in the different regions of the brain. The synchronous activity represents as ECoG of multiple neurons that is known as multi-unit activity, (MUA), whereas the recording of the neural activity is from the assemblies of the neurons that is known as single-unit activity, (SUA) that is also recordable by microelectrode system. ECoG electrodes do not penetrates the pia meter. It may penetrate the skull. The MEA penetrate pia mater. The deep brain system (DBS) is a neuronal electrode mechanical setup that penetrates inside the cortex deeply.

The following are the methods lies in invasive technique.

  1. Electrocorticography (ECoG)
  2. Multiple Electrode Array (MEA)
  3. Microelectrode or Microwire

Non-Invasive BCI Monitoring Technologies

The technologies that can monitor brain activity non-invasively are EEG, fMEG, and MRI. In these techniques and MEG are the most advance and excellent temporal improvement and resolution, The MEG and MRI have higher spatial signal resolution. In neuronal activity the MEG measures the or captures the magnetic signals. In comparison for noisy signal EEG method used. For increased blood flow in the cortex that indirectly measures with fMRI. MEG measures the normal components of cortical brain tissues, while EEG method records both activities. Both MEG and MRI requires high resolution magnetic and sensitive sensors. These technologies are complex and may not suitable for monitoring medical applications outside or the patients outside of clinical settings. In comparison the EEG setup is more suitable for this setup. It is lightweight and easily worn so the continuous sensing and monitoring of signal is possible inside or outside. The EEG and MEG have high resolution up to 1ms in non-invasive sensing techniques. The signal produced by skeleton muscles or the facial expressions lies in the Electromyogram (EMG) technique. These signals can also be produced by mental states sleep and physiological and medical abnormalities. The muscles activity measured with the electrode positions as for monitoring eyes movement the electrodes will be placed on the forehead.

The following methods lies in the in Non-invasive technologies

  1. EEG-Electroencephlography
  2. MEG-Magnetoencphalography
  3. MRI-Magnetic-Resonance-Imaging

Some of the information has been excluded in this article and some relevant picture because of copyright issue.So don’t worry if you don’t understand something or feel something missing.Search the same term and find relevant research papers and pictures you will understand each and everything.There are lots of research publication available about this topic.Literature review is necessary for this project as we should have some background knowledge about the project.This will also help students for their exam preparations.Pictures are not included due to copyright so for better understanding search the relevant pictures.

Everything will be cleared in step by step guide so stay connected for more tutorials and guides.If you have any query about the project feel free to comment below and Subscribe to our YouTube channel for video tutorials and project application ideas.stay happy and stay motivated.


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