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Seminar 1

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  • To carry out goal-directed movements, your motor cortex must first receive various kinds of information from the various lobes of the brain: information about the body's position in space, from the parietal lobe; about the goal to be attained and an appropriate strategy for attaining it from the anterior portion of the frontal lobe; about memories of past strategies, from the temporal lobe.
  • People Suffering from Misfunctioanllity in the Cerebellum their body would have great effect on the body’s balance Due to the required direction and force duration aren’t measured in the right way
  • n the human brain, planning for any given movement is done mainly in the forward portion of the frontal lobe.This part of the cortex receives information about the individual's current position from several other parts. Then, like the ship's captain, it issues its commands, to Area 6. Area 6 acts like the ship's lieutenants. It decides which set of muscles to contract to achieve the required movement, then issues the corresponding orders to the "rowers"—the primary motor cortex, also known as Area 4. This area in turn activates specific muscles or groups of muscles via the motor neurons in the spinal cord.
  • In clinical contexts the EEG is the measurement of the brain’s spontaneous electrical activity over a short period of time usually from 20-40 minutes. The waveforms recorded are thought to reflect the activity of the surface of the brain, the cortex. This activity is influenced by the electrical activity from the brain structures underneath the cortex. So basically EEG signals are electrical signals uniquely produced by the brain when performing certain actions. No EEG signal pattern is duplicated for any two distinct actions. For example moving your right arm can produce a certain EEG pattern and moving your left arm will produce a totally different and independent EEG pattern.
  • There are several placement techniques but the most standard one is called the 10/20 system –it’s called so because the electrodes are placed at positions separated by 10 to 20 per cent of the size of the whole head.
  • F-> Frontal LobeT-> Temporal LobeC-> Central LobeO-> Occipital Lobe Even Number for Right Odd Number for Left
  • Each amplifier has two inputs, An electrode is connected at each one. These amplifiers measure the voltage difference between the two signals of it’s inputs and the resulting signal is amplified and then displayed as a single channel of the EEG activity this activity is input along with another one to amplifiers that measure the potential difference between them and amplifies it to produces a single channel, so each EEG signal channel is the measuerment of the difference of the activities produced by two different parts of the brain.
  • As you can see this EEG activity(associated with blinking) is very vivid and appears easily in the EEG pattern, it can be viewed by the naked eye as the response from the brain is very high and produces high amplitudes in the signal that are easily visible
  • being happy, sad, excited, tired or confused…..it’s very difficult to believe that having certain feelings reflect to the brain activity but this shows that anything in the human being is connected to the brain
  • Of course as you can see it isn’t visible in the EEG signal since it’s contribution to the signal is small so the amplitude of the signal associated with a mental cognitive state is very small and nearly not visible by the naked eye, but we know it’s there.
  • The DC value is defined as the average value of the EEG signal, a DC drift is the change of the DC value of an EEG signal over time, and this is affected by electrode polarization where this causes extra voltage difference between the electrodes that is measured along with the EEG signal. Estimating a specific cognitive state is one of the problems solved by pattern recognition. Since it’s previously mentioned that each brain activity is associated with a specific unique EEG pattern then there would be no problem to determine a cognitive state by recognizing its pattern.
  • Neuroplasticity (also referred to as brain plasticity, cortical plasticity or cortical re-mapping) is the changing of neurons, the organization of their networks, and their function via new experiences

Seminar 1 Seminar 1 Presentation Transcript

  • Wireless Brain Controlled Robotic Arm
    1
  • Team member
    Omar El Tohamy
    Amr Emad Saleh
    Ahmed M.Nabih
    Ahmed Atef
    Aya Osama
    A.Rahman Ali
    2
  • Agenda
    Problem Statement & Objective
    Brain Anatomy
    EEG
    BCI
    Emotiv Headset
    3
  • Problem Statement & Objective
    4
  • Problem Statement
    Traumatic lesions of the central nervous system as well as neurodegenerative disorders continue to inflict devastating, and so far irreparable, motor deficits in large numbers of patients
    5
  • 300,000 Americans are spinal cord injured.
    52% of spinal cord injured individuals are considered Partial paralysis and 47% Total Paralysis
    Approximately 15,000 new injuries occur each year.
    82% are male.
    56% of injuries occur between the ages of 16 and 30
    6
  • Objective
    Help handicaps to live independently without the need of others assistance
    Providing a method to help handicaps to adapt with ubiquitous environments.
    Cover new grounds of the applications of EEG signals.
    7
  • Brain
    8
  • Brain
    The human brain is the center of the human nervous system and is a highly complex organ.
    The brain monitors and regulates the body's actions and reactions.
    9
  • Each Hemisphere into four "lobes“
    Frontal lobe.
    Parietal lobe.
    Occipital lobe.
    Temporal lobe.
    10
  • Motor Cortex
    The motor cortex is located in the rear portion of the frontal lobe
    The motor cortex is divided into two main areas, Area 4 and Area 6.
    11
  • THE CEREBELLUM
    In a healthy person, the cerebellum first receives information about the intended movement from the sensory and motor cortexes.
    Then it sends information back to the motor cortex about the required direction, force, and duration of this movement
    12
  • THE ACTIVATION SEQUENCE FOR THE MOTOR AREAS
    13
  • Brain signals & EEG
    14
  • Brain Signals & Electroencephalogram (EEG)
    EEG is a recording of the electrical activity of the brain directly from the scalp produced by the firing of neurons within the brain.
    No EEG signal pattern is duplicated for any two distinct actions
    15
  • How EEG Works ?
    Recorded by placing small metal discs called electrodes on the scalp in certain positions
    Each electrode is labeled with a letter and a number to indicate its position.
    16
  • 17
  • How the Signal is Produced
    EEG machines use differential amplifiers to produce each channel or trace of activity.
    18
  • The EEG signal itself is in the waveform so it is required that an analogue to digital signal converter be employed to produce the signal as a series of numeric values each representing voltage values of each channel at a certain time instance.
    19
  • The actions that affect the EEG signals
    1. Muscular movements
    2. Expressive states
    3. Cognitive States
    20
  • Muscular Movement
    This is defined as any physical movements
    this is because in order to move any muscle the brain performs certain actions to send orders to this muscle to move
    21
  • 22
  • Expressive States
    This refers to maintaining a specific emotional state
    This is much more difficult to measure than any muscular movement as its contribution in the overall brain activity is less.
    23
  • 24
  • Cognitive States
    A cognitive state means a person’s state of mind, it is generally said to mean a person’s thoughts.
    Surely since a thought is generated from the brain than it is expected that it would affect the brain activity and thus be reflected in the EEG signal.
    25
  • 26
  • Difficulties in Detection of EEG Signals
    The EEG signal is contaminated with eye blinks and involuntary movements that are reflected in the signal and have to be removed.
    The signal is contaminated with DC drifts
    27
  • Brain computer interface
    28
  • Brain-Computer Interface
    A brain–computer interface (BCI) is a direct communication pathway between a brain and an external device computer interface (BCI).
    It’s also known as direct neural interface or a brain–machine interface.
    BCIs are often aimed at assisting, augmenting or repairing human cognitive or sensory-motor functions.
    29
  • Brain-Computer Interface (Cont)
    The field of (BCI) has since advanced mostly toward neuroprosthetics applications that aim at restoring damaged hearing, sight and movement.
    Thanks to the remarkable cortical plasticity of the brain, signals from implanted prostheses can, after adaptation, be handled by the brain like natural sensor or effector channels.
    30
  • Emotiv
    31
  • EMOTIV Headset
    32
  • EMOTIV Headset (Cont)
    EMOTIV Headset is a brain-computer interface (BCI) based on EEG.
    EMOTIV Headset will make it possible for games and applications to be controlled and influenced by the player's mind, and facial expressions.
    33
  • EMOTIV Headset (Cont)
    The EMOTIV Headset (EPOC) has 14 electrodes(compared to the 19 electrodes of a standard medical EEG).
    It also has a two-axis gyro for measuring head rotation.
    The headset must first be trained to recognize what kind of thought pattern equates to a certain action.
    34
  • EMOTIV Headset (Cont)
    It can measure four categories of inputs:
    Conscious thoughts
    Emotions
    Facial expressions
    Head rotation
    35
  • References
    http://www.Emotiv.com
    http://www.gtec.at/products/g.BCIsys/BrainComputerInterface.pdf
    http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0000042
    http://www.wikipedia.org/  
    36