Consciousness

Question 1

Define wakefulness.

Answer 1

ability to open your eyes and have basic reflexes such as coughing, swallowing and sucking

Question 2

Compare wakefulness and awareness.

Answer 2

Awareness - more complex thought processes.

Wakefulness - presence of basic reflexes.

Question 3

Define consciousness.

Answer 3

processes enabling us to experience world; distinct from automatic behaviours that occur unconsciously

Question 4

How does complexity change with levels of consciousness?

Answer 4

will be reduced when asleep or unconscious, and higher when awake

Question 5

What are the neural correlates of consciousness?

Answer 5

minimum neuronal mechanisms sufficient for one specific conscious experience - localises to a posterior hot zone including sensory areas

Question 6

What is the role of the RAS?

Answer 6

modulate alertness and consciousness.

Question 7

Explain the structure of the reticular formation.

Answer 7

polysynaptic network in core of medulla, pons and upper medulla.

Contains NA and Ach NT neurones.

Project into cortex via thalamus to increase activity.

Question 8

What are the reticular formation inputs?

Answer 8

Touch/pain from ascending tracts

Vestibular from medial vestibular nucleus

Auditory from inferior colliculus

Visual from superior colliculus

Olfactory via medial forebrain bundle

Question 9

What are the reticular formation outputs?

Answer 9

To the ventral tegmental area (dopaminergic neurones) in midbrain

To the locus coeruleus (noradrenergic neurones) in the pons

To the thalamus (cholinergic neurones)

Question 10

Explain electroencaphalography.

Answer 10

Using scalp electrodes to measure brain activity and determine frequency of brain waves.

Question 11

What are the frequencies of deltla, theta, alpha and beta brain waves,

Answer 11

Delta: <4Hz

Theta: 4-8Hz

Alpha: 8-13Hz

Beta: 13-30Hz

Question 12

-What do beta, alpha, theta and delta waves look like? Also describe sleep spindles and REM sleep waves.

Answer 12

Question 13

What is the Glasgow Coma Score used for?

Answer 13

determine level of consciousness

Question 14

Explain the response to stimulation of a patient in a coma.

Answer 14

ABSENT wakefulness, ABSENT awareness; unrousable unresponsiveness where patient cannot be woken, does not have a normal sleep cycle and has no response to pain

Question 15

Explain the responses of a patient in a vegetative state to stimulation.

Answer 15

wakefulness, ABSENT awareness; preserved capacity for spontaneous/stimulus arousal (sleep wake cycles and range of reflexive behaviour) but complete absence of behavioural evidence for self or environmental awareness - destruction of cortex and hemispheres but intact RAS

Question 16

Explain the responses of a minimally conscious patient to stimulation.

Answer 16

wakefulness, MINIMAL awareness; minimal but clearly discernible behavioural evidence of self/environmental awareness - characterised by inconsistent and reproducible responses above level of spontaneous/reflexive behaviour

Question 17

Explain the responses of a patient with locked in syndrome to stimulation.

Answer 17

wakefulness and awareness; intact cortex and RAS, but damage to ventral pons means can’t move or talk

Question 18

Table used to determine GCS score.

Answer 18

Question 19

Name some metabolic causes of coma.

Answer 19

overdose, hypoglycaemia, diabetes, hypercalcaemia

Question 20

Name some diffuse intracranial causes of coma.

Answer 20

head injury, meningitis, subarachnoid, encephalitis, epilepsy, hypoxic brain injury

Question 21

What hemisphere lesions might lead to a coma?

Answer 21

cerebral infarct, cerebral haemorrhage, abscess, tumour

Question 22

What brainstem lesions might lead to a coma?

Answer 22

brainstem infarct, tumour, abscess, cerebellar haemorrhage, cerebellar infarct

Question 23

Define brain death.

Answer 23

Irreverisble coma due to brainstem death.

Life support to body.

Question 24

Define coma.

Answer 24

unreactive unresponsiveness, with neither wakefulness or awareness, but intact brainstem

Question 25

Define persistent vegetative state.

Answer 25

irreversible coma due to brainstem-cortex disconnection or widespread cortical damage; brainstem still functions reflexively, and sleep-wake cycle present; patient is not conscious and unaware of surroundings.