11 The Brainstem and Conciousness

Question 1

How can we define conciousness?

Answer 1

Awareness of external environment

Arousal: the emotional state associated with some kind of goal or avoidance of something harmful

Question 2

Conciousness requires 2 components: a cerebral cortex and a reticular formation. How do these 2 interact with each other?

Answer 2

Each can have excitatory effect on the other one

Positive feedback loop created

Question 3

What is the reticular formation? Where is it found?

Answer 3

Reticular Formation= population of specialised interneurones in brainstem

(runs length of brainstem)

Question 4

What are the inputs to the reticular formation?

Answer 4

From somatosensory system and the cortec

Question 5

Describe what forms the reticular activating system. (ie what are the outputs of the reticular formation, what does this cause the release of in the cortex?)

Answer 5

• Reticular formation has excitatory output to:
  
  • Basal forebrain nuclei
  • Hypothalamus
  • Thalamus
• Each release in the cortex:
  
  • Basal forebrain nuclei- ACh
  • Hypothalamus- Histamine
  • Thalamus- Glutamate
• …these neurotransmitters all have an excitatory effect

Question 6

What does the glasgow coma scale assess? What’s the highest and lowest score?

Answer 6

Glasgow coma scale= used to assess conciousness

Looks at: eye opening, motor response and verbal response

Highest score= 15

Lowest score= 3

Question 7

What is an EEG? What can it be used for?

Answer 7

Electroencephalogram (EEG)

Can be used as diagnostic tool for sleep problems

Question 8

How many stages of sleep are there?

Answer 8

5 stages of sleep

REM, stage 1, 2, 3, 4

Question 9

Fill in the missing labels showing the EEG forms for the different stages of sleep

Answer 9

Question 10

Outline the neural mechanism of sleep.

Answer 10

Question 11

Describe the paradox of REM sleep including:

• Where the initiation of REM sleep comes from
• How the EEG appears during REM sleep
• How easy it is to rouse a person during REM sleep
• What happens to motor functions during REM sleep
• What happens to muscle tone during REM sleep and why?

Answer 11

Question 12

What is narcolepsy?

Answer 12

Long-term neurological disorder that involves a decreased ability to regulate sleep-wake cycles. Symptoms often include periods of excessive daytime sleepiness and brief involuntary sleep episodes.

=very rare

Question 13

Differentiate between the definition of a coma and a persitent vegetative state.

Answer 13