15-06-2012, 11:04 AM
BRAIN MACHINE INTERFACE.
[attachment=24514]
Introduction
Brain-Machine Interface (BMI) is a communication system, which enables the user to control special computer applications by using only his or her thoughts.
Different research groups have examined and used different methods to achieve this. Almost all of them are based on electroencephalography (EEG) recorded from the scalp.
Our major goal of such research is to create a system that allows patients who have damaged their sensory/motor nerves severely to activate outside mechanisms by using brain signals
BMI VERSUS NEUROPROSTHETIC
Neuroprosthetics is an area of neuroscience concerned with neural prostheses using artificial devices to replace the function of impaired nervous systems or sensory organs.
The differences between BMIs and neuroprosthetics are mostly in the ways the terms are used.
General principle underlying BMI
In healthy subjects the primary motor
area of the brain sends movement
commands to the muscles via the spinal cord.
In many paralyzed people this pathway is
interrupted i.e. due to a spinal cord injury.
A new treatment being researched:
Electrodes measure activity from brain. A computer based decoder translates this activity into commands for the control of muscles , a prosthesis or a computer.
ELECTROENCELOGRAPHY
Electroencephalography (EEG) is a method used in measuring the electrical activity of the brain. The brain generates rhythmical potentials which originate in the individual neurons of the brain.
The EEG signal can be picked up with electrodes either from scalp or directly from the cerebral cortex. As the neurons in our brain communicate with each other by firing electrical impulses, this creates an electric field which travel though the cortex, the skull and the scalp.
The peak-to-peak amplitude of the waves that can be picked up from the scalp is normally 100 uv or less while that on the exposed brain, is about lmV. The frequency varies greatly with different behavioral states. The normal EEG frequency content ranges from 0.5 to 50 Hz.
Frequency information is particularly significant since the basic frequency of the EEG range is classified into five bands for purposes of EEG analysis.
Frequencies in delta band are generated from BRAIN in adults slow wave sleep or in babies(found in deep sleep).
Frequencies of theta band are generated in sleep, meditation, hypnosis
Alpha signals are produced while relaxing or closing the eyes.
Beta signals are produced while working, active, busy or anxious thinking.
Gamma signals are produced while certain cognitive or motor functions.
Common EEG Frequency ranges
MRI (magnetic resonance image)
Another way to measure Brain activity is with MRI.
to map where in the brain electrodes should be placed to measure a specific function.
but cant be used as apart of permanent or semi permanent BMI.
for example , if researchers are attempting to implant electrode that will allow the some one to control a robotic arm.
BMI APPROACHES
pattern recognition approach is based on the cognitive mental task.
Operant conditioning approach is based on the self regulation of EEG response.
BLOCK DIAGRAM DESCRIPTION
The BMI consists of several components:
1. The implant device, or chronic multi-electrode array 2. The signal recording and processing section 3. An external device the subject uses to produce and control motion 4. A feed back section to the subject.
BMI COMPONENTS
Its scientific interpretation is combination of several hardware and software components.
Implant Device
EEG are recorded with electrodes , which are placed on the scalp.
Electrodes are small plates , which conduct electricity.
Few major problems when developing neural implants.
Electrode placement
Signal Processing section
Multi channel Acquisition Systems
2 . Spike Detection
Incorporating spike detection will allow the BMI to transmit only the action potential waveforms and their respective arrival times instead of row signal in its entirety
3. Signal Analysis
Feature extraction and classification of EEG are dealt in this section. In the simplest form a certain frequency range is selected and amplitude related to some reference level measured.
Feature sets are distinct enough ,any classifier can classify them.
External Device
The device control simply transforms the classification to a particular action.
The action can be, e.g., an up or down movement of a cursor on the feedback screen or a selection of a letter in a writing application.
Feedback
One is the ‘online’ control and correction of errors during the execution of a movement.
The other is learning: the gradual adaptation of motor commands, which takes place after the execution of one or more movements.
Advantages
1. In this era where drastic diseases are getting common it is a boon if we can develop it to its full potential.
2. By this humans get gradual co-evolution with computers.
3. Even spinal chord functioning can be achieved using BMI.
4. Linking people via chip implants to super intelligent machines seems to a natural progression —creating in effect, super humans.
5. Linking up in this way would allow for computer intelligence to be hooked to natural brain giving immediate access to internet, enabling phenomenal math capabilities and computer memory.
Challenges
1. Connecting to the nervous system could lead to permanent brain damage, resulting in the loss of feelings or movement, or continual pain. 2. In the networked brain condition —what will mean to be human?
3. Brain signals are weak and prone to interference. 4. Only a few mental tasks can be done.
5. Virus attacks may occur to brain causing ill effects. 6. Equipment is less than portable. It requires a wired connection to the Computer.
Applications
Research
Medical:
1. Auditory and visual prosthesis
2. Functional-neuromuscular stimulation (FNS)
3. Prosthetic limb control
thought controlled motorized wheel chair.
thought controlled prosthetic arm for amputee
CONCLUSION
human life are always valued over and above machines. What happens when humans merge with machines?
The question is not what will the computer be like in the future ,but instead ,what will we be like ? What kind of people are we becoming?
BMI’S will have the ability to give people back their vision and hearing. They will also change the way a person looks at the world .Someday these devices might be more common than keyboards.
Is someone with a synthetic eye, less a person than someone without?
[attachment=24514]
Introduction
Brain-Machine Interface (BMI) is a communication system, which enables the user to control special computer applications by using only his or her thoughts.
Different research groups have examined and used different methods to achieve this. Almost all of them are based on electroencephalography (EEG) recorded from the scalp.
Our major goal of such research is to create a system that allows patients who have damaged their sensory/motor nerves severely to activate outside mechanisms by using brain signals
BMI VERSUS NEUROPROSTHETIC
Neuroprosthetics is an area of neuroscience concerned with neural prostheses using artificial devices to replace the function of impaired nervous systems or sensory organs.
The differences between BMIs and neuroprosthetics are mostly in the ways the terms are used.
General principle underlying BMI
In healthy subjects the primary motor
area of the brain sends movement
commands to the muscles via the spinal cord.
In many paralyzed people this pathway is
interrupted i.e. due to a spinal cord injury.
A new treatment being researched:
Electrodes measure activity from brain. A computer based decoder translates this activity into commands for the control of muscles , a prosthesis or a computer.
ELECTROENCELOGRAPHY
Electroencephalography (EEG) is a method used in measuring the electrical activity of the brain. The brain generates rhythmical potentials which originate in the individual neurons of the brain.
The EEG signal can be picked up with electrodes either from scalp or directly from the cerebral cortex. As the neurons in our brain communicate with each other by firing electrical impulses, this creates an electric field which travel though the cortex, the skull and the scalp.
The peak-to-peak amplitude of the waves that can be picked up from the scalp is normally 100 uv or less while that on the exposed brain, is about lmV. The frequency varies greatly with different behavioral states. The normal EEG frequency content ranges from 0.5 to 50 Hz.
Frequency information is particularly significant since the basic frequency of the EEG range is classified into five bands for purposes of EEG analysis.
Frequencies in delta band are generated from BRAIN in adults slow wave sleep or in babies(found in deep sleep).
Frequencies of theta band are generated in sleep, meditation, hypnosis
Alpha signals are produced while relaxing or closing the eyes.
Beta signals are produced while working, active, busy or anxious thinking.
Gamma signals are produced while certain cognitive or motor functions.
Common EEG Frequency ranges
MRI (magnetic resonance image)
Another way to measure Brain activity is with MRI.
to map where in the brain electrodes should be placed to measure a specific function.
but cant be used as apart of permanent or semi permanent BMI.
for example , if researchers are attempting to implant electrode that will allow the some one to control a robotic arm.
BMI APPROACHES
pattern recognition approach is based on the cognitive mental task.
Operant conditioning approach is based on the self regulation of EEG response.
BLOCK DIAGRAM DESCRIPTION
The BMI consists of several components:
1. The implant device, or chronic multi-electrode array 2. The signal recording and processing section 3. An external device the subject uses to produce and control motion 4. A feed back section to the subject.
BMI COMPONENTS
Its scientific interpretation is combination of several hardware and software components.
Implant Device
EEG are recorded with electrodes , which are placed on the scalp.
Electrodes are small plates , which conduct electricity.
Few major problems when developing neural implants.
Electrode placement
Signal Processing section
Multi channel Acquisition Systems
2 . Spike Detection
Incorporating spike detection will allow the BMI to transmit only the action potential waveforms and their respective arrival times instead of row signal in its entirety
3. Signal Analysis
Feature extraction and classification of EEG are dealt in this section. In the simplest form a certain frequency range is selected and amplitude related to some reference level measured.
Feature sets are distinct enough ,any classifier can classify them.
External Device
The device control simply transforms the classification to a particular action.
The action can be, e.g., an up or down movement of a cursor on the feedback screen or a selection of a letter in a writing application.
Feedback
One is the ‘online’ control and correction of errors during the execution of a movement.
The other is learning: the gradual adaptation of motor commands, which takes place after the execution of one or more movements.
Advantages
1. In this era where drastic diseases are getting common it is a boon if we can develop it to its full potential.
2. By this humans get gradual co-evolution with computers.
3. Even spinal chord functioning can be achieved using BMI.
4. Linking people via chip implants to super intelligent machines seems to a natural progression —creating in effect, super humans.
5. Linking up in this way would allow for computer intelligence to be hooked to natural brain giving immediate access to internet, enabling phenomenal math capabilities and computer memory.
Challenges
1. Connecting to the nervous system could lead to permanent brain damage, resulting in the loss of feelings or movement, or continual pain. 2. In the networked brain condition —what will mean to be human?
3. Brain signals are weak and prone to interference. 4. Only a few mental tasks can be done.
5. Virus attacks may occur to brain causing ill effects. 6. Equipment is less than portable. It requires a wired connection to the Computer.
Applications
Research
Medical:
1. Auditory and visual prosthesis
2. Functional-neuromuscular stimulation (FNS)
3. Prosthetic limb control
thought controlled motorized wheel chair.
thought controlled prosthetic arm for amputee
CONCLUSION
human life are always valued over and above machines. What happens when humans merge with machines?
The question is not what will the computer be like in the future ,but instead ,what will we be like ? What kind of people are we becoming?
BMI’S will have the ability to give people back their vision and hearing. They will also change the way a person looks at the world .Someday these devices might be more common than keyboards.
Is someone with a synthetic eye, less a person than someone without?