Circadian Rhythm and EEG Flashcards

1
Q

What does the hypothalamus excrete that is essential for being awake? What is a condition that has a deficiency of this?

A

An excitatory neurotransmitter called orexin/hypocretin.

Narcolepsy is a condition where the patient falls asleep suddenly due to a deficiency in orexin signalling.

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2
Q

What is an EEG and what does it do?

A

Electroencephalogram

Monitors brain pattern by placing electrodes on the scalp to detect underlying neurones.

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3
Q

What two things does an EEG display sleep as?

A

Frequency and Amplitude

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4
Q

What type of waves are shown when relaxed and awake?

A

High frequency and amplitude alpha waves

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5
Q

What type of waves are shown when alert and awake?

A

Higher frequency and low amplitude, asynchronous beta waves

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6
Q

What type of waves are shown in deep sleep?

A

Low frequency and high amplitude delta waves

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7
Q

What characterises theta waves and when do they occur?

A

Low frequency and varying amplitude waves.

Present in sleep, common in children. Adults can have them when emotionally stressed and frustrated.

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8
Q

How many stages are there in the sleep cycle? How many are slow wave sleep and how many are fast wave sleep?

A

Five
Stage one to four are slow wave sleep
REM sleep is fast wave sleep

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9
Q

What is stage one in the sleep cycle?

A

Light sleep and easily roused with slow eye movements. Low frequency and high amplitude theta waves.

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10
Q

What is stage two in the sleep cycle?

A

Frequency slows further and eye movements decrease

Get sleep spindles (cluster of rhythmic waves)

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11
Q

What is stage three in the sleep cycle?

A

Sleep spindle activity declines. Delta waves interspersed with short episodes of fast waves.

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12
Q

What is stage four in the sleep cycle?

A

Deep sleep with only delta waves. Sleep walking/talking occurs here and the person can move position without making that decision.

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13
Q

What is stage five in the sleep cycle?

A

REM/rapid eye movement sleep/paradoxical sleep

Skeletal muscles of whole body inhibited from pons to spinal cord apart from the eyes so cant act out dreams.

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14
Q

What is a disease where the inhibition of skeletal muscles during REM doesn’t work?

A

REM sleep behavioural disorder

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15
Q

What are some consequences of sleep deprivation

A

Decreased cognitive and physical function
Sluggishness
Irritability
Psychosis (uncommon)

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16
Q

What are two types of insomnia?

A

Primary chronic insomnia where a cause is unclear

Secondary temporary insomnia where deep trauma causes a short lived insomnia, usually self limiting.

17
Q

Where in the brain is the circadian rhythm controlled and what are the stimulants?

A

Suprachiasmatic Nucleus (SCN) of the hypothalamus. Stimulated by light and dark. If SCN is destroyed then the circadian rhythm is lost.