2. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
3. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
4. Introduction The human brain activity start between 4-5 months before parental development. The human brain represent the brain functional side to side the status of the whole body. EEG signals measured from the brain of a human. The medium defines the path from neurons, as so called signal sources to electro nodes which are the sensors.
5. studying neural functions and neurophysicological properties of the brain together with the mechanisms underlying the generation of the signals for detection, diagnosis and treatment of brain disorders and the related diseases. Note :-
6. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
7. History Carlo Matteucci (1811–1868) and Emil Du Bois-Reymond (1818–1896) were the first people to register the electrical signals emitted from muscle nerves using a galvanometer and established the concept of neurophysiology. Analysis of EEG signals started during the early days of EEG measurement. Berger assisted by Dietch (1932) applied Fourier analysis to EEG sequences.
13. In animals can be several meters but in humans the length can be a percentage of millimeter to a meter .
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16. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
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18. If an action potential travels along the fibre, which ends in an excitatory synapse, an excitatory postsynaptic potential (EPSP) occurs in the following neuron.
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21. Action Potentials (AP) APs are caused by an exchange of ions across the neuron membrane and an AP is a temporary change in the membrane potential that is transmitted along the axon. The conduction velocity of action potentials lies between 1 and 100 m/s. APs are initiated by many different types of stimuli; sensory nerves respond to many types of stimuli, such as chemical, light, electricity, pressure, touch, and stretching.
22. Action potentials processes The action must be more than gate threshold value. Depolarization . Sodium gates close. 4. Potassium gates open. Repolarization. Hyperpolarization.
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24. Brain cells active mode (get a new action potential), the cell produced within dendrites so this current generate a magnetic field (EMG) that cover over scalp.
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26. When the human receive the action he could feel 1 % of the action, as it arrives to his brain and the other noise generated within scalp and skull.
27. Therefore, to feel action potential there must be a lot of active neurons can generate potential.
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29. The amplitudes and frequencies of such signals change from one to another.
30. This waves from low to high (alpha , theta, beta ,delta ,gamma)
33. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
34. EEG Recording and Measurement Signal EEG FMRI MEG EEG :- Electroencephalogram. FMRI:- Functional Magmatic Resonance imaging. MEG:- Magnetoencephalogram. The functional and physiological changes within brain can registered by EEG,MEG and FMRI.
35. The reasons of not using FMRI about using EEG,MEG Time resolution of FMRI image is very low (2 frames/sec).EEG bandwidth can be viewed using EEG or MEG signal. Many types of mental activities brain disorders cannot be registered using FMRI. Accessibility of FMRI systems is limited and costly.
36. EEG system consists of To convert from analog signal to digital signal:- 1) Sampling. 2) Quantization. 3) Encoding. Needle Electrodes Filters Amplifiers
41. Note Although the format of reading the EEG data may be different for different EEG machines, these formats are easily convertible to spreadsheets readable by most signal processing software packages such as MATLAB.
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43. Filters Are used to make suitable for processing and visualization. Is divided to:- High pass filter:- remove distributing very low frequency components. 2) Low pass filter:- remove distributing very high frequency components.
47. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
48. Ageing The ageing process affects the normal cerebral activity in waking and sleep, and changes the response of the brain to stimuli. The charges stem from reducing the number of neurons and due to a general change in the brain pathology. General cause for ageing of brain may be decrease in cerebral blood flow. The REM duration decrease during the night. Dementia increases dramatically with ageing.
49. Agenda Introduction. History. Neural Activities. Action Potentials. EEG Generation. Brain Rhythms. EEG Recording and Measurement. Conditioning the Signals. Abnormal EEG Patterns. Ageing. Mental Disorders.
50. Mental Disorders Is divided to Epileptic Seizure and No epileptic attacks Psychiatric Disorders Dementia External Effects
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53. Sub cortical dementias introduce less abnormality to the EEG patterns than the cortical ones.
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56. 4)External Effects EEG signal patterns may significantly change when using drugs for the treatment and suppression of various mental and CNS abnormalities. Variations in EEG patterns may also arise by just looking at the TV screen or listening to music without any attention. However, among the external effects the most significant ones are the pharmacological and drug effects. Therefore, it is important to know the effects of these drugs on the changes of EEG
