Consciousness and Brain Activity

Question 1

What is the medical definition of consciousness?

Answer 1

State of awareness and responsiveness to one’s surroundings

Question 2

What is the “lowest” level of consciousness?

Answer 2

Brain death

Question 3

Describe Locked in Syndrome

Answer 3

Patient has awareness, sleep-wake cycles, meaningful behaviour but is isolated due to facial / muscle paralysis

Question 4

Describe a state of normal loss of consciousness

Answer 4

Sleeping

Question 5

Describe three states of abnormal loss of consciousness

Answer 5

Coma
Anaesthesia
Vegetative State

Question 6

What is the most common cause of serious loss of consciousness worldwide?

Answer 6

Cerebral malaria

Question 7

Aside from Cerebral Malaria, give 4 other causes of losing consciousness

Answer 7

Stroke
Cardiovascular
Diabetes
Drug-induced
Epilepsy
Head Injury
Dementia

Question 8

What is AVPU?

Answer 8

A way of assessing patient’s responsiveness

A: Patient is awake
V: Patient responds to voice
P: Patient responds to pain
U: Patient unresponsivess

Question 9

A fully conscious patient has a GCS of..?

Answer 9

15 (maximum)

Question 10

A person in a deep coma has a GCS of..?

Answer 10

3 (minimum)

Question 11

What are the three variables measured for the Glasgow Coma Scale?

Answer 11

Best Eye Response (E)
Best Verbal Response (V)
Best Motor Response (M)

Question 12

To be in a coma, patient would have a GCS of..?

Answer 12

8 or less

Question 13

A GCS of 9 - 11 is..?

Answer 13

Moderately severe injury

Question 14

A GCS greater than or equal to 12 is..?

Answer 14

Minor injury

Question 15

What is the criteria for brain stem death?

Answer 15

Irreversible loss of capacity for consciousness, to breathe, and loss of brain-stem function

Question 16

Give examples of 5 brainstem reflexes

Answer 16

• Pupil response
• Corneal reflex
• Vestibular-ocular reflex (VOR)
• Cough / gag reflex
• Respiratory effort

Question 17

What is the main system in the brain which regulates consciousness?

Answer 17

Reticular Activating System

Question 18

What is the Reticular Formation?

Answer 18

A collection of nuclei belonging to the Reticular Activating System, found in the mid-brain. Diffuse, no clear boundaries

Question 19

What are the four principle sets of nuclei in the Reticular Activating System?

Answer 19

Locus Coeruleus
Raphe Nuclei
Ventral Tegmental Area
Cholinergic Nuclei

Question 20

What are the Neurotransmitters used in each of the Nuclei of the RAS?

Answer 20

Locus Coeruleus: NA
Raphe Nuclei: 5-HT
Ventral Tegmental Area: DA
Cholinergic Nuclei: ACh

Question 21

What are the two main types of sleep?

Answer 21

Synchronised / NREM / Non-REM

Desynchronised / REM

Question 22

The sleep-wake cycle is controlled by what fibres in the RAS?

Answer 22

Cholinergic Nuclei

Question 23

Oscillations in the EEG are generated by interactions between which 3 neurones?

Answer 23

• Thalamocortical
• Reticular
• Corticothalamic

Question 24

During wakefulness, what sort of oscillatory waves are there?

Answer 24

Alpha and beta waves

Question 25

How long is the body clock’s day?

Answer 25

24.5 - 25.5 hrs