T1 L14: Consciousness

Question 1

What us the Glasgow coma scale?

Answer 1

A clinical scale used to reliably measure a person’s level of consciousness after a brain injury

Question 2

Give examples of disorders of consciousness

Answer 2

Sleep
Psychedelic states 
General anaesthesia 
Coma
PVS (persistent vegetative state)
MCS (minimal conscious state)
Locked in Syndrome

Question 3

What is a Psychedelic state?

Answer 3

A temporary altered state of consciousness induced by the consumption of a psychedelic substance (most commonly LSD, mescaline, psilocybin mushrooms, or DMT)

Question 4

Which types of waves are present in deep sleep?

Answer 4

Low frequency waves

Question 5

What are some causes of coma?

Answer 5

Sedation (anaesthesia)
Epilepsy
Electrolyte/metabolic imbalance
Disturbance of thermoregulation
Raised intracranial pressure
Structural damage to the brainstem/thalamus/cortex caused by: Stroke, Trauma, Tumour, Inflammation, or Infection

Question 6

What is the definition of a coma?

Answer 6

Complete prolonged loss of wakefulness and unresponsiveness to external stimuli. It’s often reversible

Question 7

What are some causes of metabolic coma?

Answer 7

Hepatic, Uraemia, Diabetic, Pancreatic, Adrenocorticoid failure

Question 8

What is Triphasic theta?

Answer 8

Abnormal EEG waves indicating some pathologies like toxic, metabolic, and structural abnormalities

They appear as non-specific, high amplitude, sharply contoured waves with a unique morphology

Question 9

What does the Glasgow coma scale include?

Answer 9

Eyes, verbal, and motor responses

The lowest you can get is 3 and the highest is 15.

Question 10

What does absent eye-opening distinguish between?

Answer 10

Coma/brainstem death from PVS and MCS

Question 11

What is a vegetative state characterised by?

Answer 11

When a person is awake but is showing no signs of awareness. They have no voluntary response to the environment

Question 12

What is the time frame for a persistent vegetative state?

Answer 12

> 4 weeks

Question 13

What is the time frame for a permanent vegetative state?

Answer 13

6 months (UK)
3 months (US)

1 year after a traumatic brain injury

Question 14

What is unresponsive wakefulness syndrome (UWS)?

Answer 14

Describes patients who fail to show voluntary motor responsiveness in the presence of eyes-open wakefulness. It’s not yet fully defined

Question 15

What is a minimal conscious state characterised by?

Answer 15

It's like a vegetative state by has one of the 11 following:
Consistent movement to command
Reproducible movement to command 
Object recognition
Object localisation
Reaching
Visual pursuit
Fixation
Automatic motor response
Object manipulation
Localisation to noxious stimulation 
Intelligible but non-functional verbalisation

Question 16

In an experiment, how was a vegetative state detected?

Answer 16

The participants were asked to imagine playing tennis and then imagine walking around their house. Different areas of the brain would light up

Question 17

What is locked in syndrome characterised by?

Answer 17

Aroused and awake but unable to respond. These people can only move their eyes up and down but not horizontally

Question 18

What causes locked in syndrome?

Answer 18

Ventral pontine damage or Severe Guillain-Barre syndrome

Question 19

What is ventral pontine damage?

Answer 19

A type of bilateral damage to the pons

Question 20

What is Guillain-Barre syndrome?

Answer 20

An acute disorder of the peripheral nerves, often preceded by a respiratory infection, causing weakness and often paralysis of the limbs. Most people will recover from it within a year

Question 21

Which reflexes are absent in brainstem death?

Answer 21

Pupils
Ice Caloric
Corneal
Pain
Gag
Cough

Question 22

What are some legalities behind taking someone off life support?

Answer 22

• There must be a presence of an irreversible cause (Eg. Anoxia, Structural damage)
• There must be an absence of reversible causes (Eg. drugs, hypothermia, alcohol, poisons)
• There must be irreversible cessation of function of the brainstem, cerebral cortex, or the body

Question 23

What are Von Economo neurons?

Answer 23

Have a large spindle-shaped soma. They have a single dendrite facing opposite

Question 24

Where are Von Economo neurons found?

Answer 24

Only in the anterior cingulate cortex (ACC) and Fronto-insular cortex (FI)

Question 25

What does the insula do?

Answer 25

It has homeostatic functions related to basic survival needs, such as taste, visceral sensation, and autonomic control

Question 26

What is the Claustrum?

Answer 26

It acts as a conductor for inputs from the cortical regions so these respective areas do not become unsynchronized

Question 27

What is the Intralaminar Thalamic Nuclei?

Answer 27

It’s a non-specific arousing system in the brain

Question 28

Which structures make up the Serotonergic nuclei?

Answer 28

The dorsal raphe and the median raphe

Question 29

Which structures make up the Dopaminergic nuclei?

Answer 29

The ventral tegmental area and the substantia nigra pars compacta

Question 30

Which structures make up the Noradrenergic nuclei?

Answer 30

The locus coeruleus and the related brainstem nuclei

Question 31

Which structures make up the Histaminergic nuclei?

Answer 31

The turbo-mamillary nucleus

Question 32

Which structures make up the Cholinergic nuclei?

Answer 32

Basal nucleus of Meynert (Attention) and Pontine tegmentum: laterodorsal tegmental nucleus and the pedunculopontine nucleus

Question 33

What role does the anterior cingulate cortex play in consciousness?

Answer 33

Error detection and conflict monitoring
Sense of violation 
Registration of pain
Social evaluation 
Reward-based learning

Question 34

What is the default mode network (DMN)?

Answer 34

A network of interacting brain regions that is active when a person is not focused on the outside world

It primarily composed of the medial prefrontal cortex, the anterior cingulate cortex, angular gyrus, hippocampus and para-hippocampus