Electrical activity of brain

Question 1

بسم الله الرحمن الرحيم وبه نستعين
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Define Evoked potential

Answer 1

Recodring the electrical activity of the cerebral cortex after stimulating receptors
And electordes are placed on the stimulated excited cortical area
Results:
Primary evoked potential : Localized Small + wave followed By -wave
2ry Evoked Potential : Large Diffuse + Wave due to >?RAS Activating Nos specific thalamic Nuclei Activating WHole Cortex

Question 2

The imp of EVOKED potential mention 2

Answer 2

Mapping of the brain
Diasgnosis of diseases

Question 3

Define
Sponatrous potential
ElectoEncephalogram
Brain waves

Answer 3

Recording Brain spontanuous electrical activity in consiuous perosn with Electrodes placed on scalp respresnting the summation of Excitatiory and Inhibitory Post synaptic potential not action potential
To record Alpha waves in Following 3C conditions :
=Calm Room
=Complete Physical and mental Rest
=Comfortable Temperaute

Question 4

Compare between alpha and beta waves according to
Frequency
Voltage
site
Charavter
Represent
recorded in

Answer 4

Frequency:
alpha = 8-13 Hz beta = 13-30 Hz
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Voltage :
Alpha=50Hz ,beta = 25Hz
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Site :
alpha =Occipital ,Frontal and pariteal
Beta: Frontal + parital
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Charcter :
Alpha:Synchronized Regular
Beta: desyncrhonized Irregular
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Alpha represents : Non specfic thalmic nuclei actication
Beta: RAS activation
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=Alpha recorded in ? Awake Adult Relaxed with closed eyes
=Beta: Awake Adult with mental activity with open eyes

Question 5

Compare between theta and delta waves according to
Frequncy
votlage
site
cheravter
represcnt
Conditions

Answer 5

Frequency
Theta : 4-7 Hz but delta 2-3.5 Hz
Voltage: Both 100 uV
Site:
Theta: ParitoTemopral
Delta: All Cortical areas
Character :
Theta AND deltal both regular Syncrhonized
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conditions :
Theta: Child + Light sleep + Emotional stress as frustation
Delta: Infants+ deep sleep deep coma &damage

Question 6

Compare between deep and light sleep waves

Answer 6

Deep delta d for d
Light sleep Theta

Question 7

describe gamma waves

Answer 7

30-80Hz
__________
0,5-2V
__________
ALL Cortical areas
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Desynchronized irregular
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in Highly aroused with high mental activity

Question 8

Give definition for Alpha block
2-Alert response
3-Arousal Response
4-desynchronizaTION

Answer 8

It is a desynchronization respnse when a releaxed perosn with closed eyes recording alpha ryhtm open his eyes or focus on something replacing alpha reythm with Beta desynchronized Rythm it is called alpha block due acrivation Of ARAS

Question 9

List 4 values of EEG

Answer 9

Non invasive study for? S2EB
1-Sleep stages and disorders
2-Site of brain tumor
3-Epilipsy
4-Brain death with flat waves

Question 10

Describe conscousness

Answer 10

it is awareness of self ,surroundings, Toughts and emotions
due to ?
RAS activating Nonspecific thalamic Nuclei activating whole cortex & may be hypothalamus
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Maintained by +Feed back by ? CorticoFugal fibers activating RAS ACTIVATING CORTEX ACTIVATING RAS AND so on,
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Question 11

Consciousness is weakened by ?

Answer 11

Fatigue of Neurons reducing + feed back
Activation of sleep centers inhibting RAS

Question 12

cOMPARE BETWEEN COMA AND SLEEP

Answer 12

Coma unconscouness from which person cannot be arousde by stimlui
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sleep Physiological sponatnuous unconsicuoness from which arousd by stimuli

Question 13

Functions of sleep

Answer 13

NMR
1 -Restoration of physiological and biochemial states ( CMTI Cognition , caloric,metabolic , thermal ,immue
2-learning an dmemory
3-Neural plasticity maturation ,

Question 14

وله مافي السماوات والأرض وله الدين واصبا أفغير الله تتقون ؟