consciousness

Question 1

define consciousness *

Answer 1

the subject experience of the mind, self and world around us

the state of being aware of and responsive to one’s surroundings

that there is something it is like to be in the state of the subjective or 1st person point of view

Question 2

what is the challenge of consciousness *

Answer 2

the easy problem - how does the brain do behaviour etc from basic machinery

hard problem - why should that feel like anything, the 1st person conscious experience

Question 3

what are the 3 elements of consciousness *

Answer 3

level - asleep/awake -

content - look awake but content can range from noting to a rich experience, specific awareness of mental states

self - confidence that we are us

Question 4

describe the content and level of coma *

Answer 4

low both

eyes not open

no awareness

Question 5

describe the content and level of vegitative state *

Answer 5

level - high - eyes open

low content

Question 6

describe the content and level of locked in syndrome *

Answer 6

high level and content

just paralysed - motor problem

Question 7

describle level and content of minimally conscious state eg dementia *

Answer 7

variable and reproducible minimal degree of consciousness

high level

Question 8

describe level and content of sleep *

Answer 8

level and content gets lower as sleep deeper

REM - level (eyes closed but moving), rish content - dreams

Question 9

describe how the RAS is involved in consciousness *

Answer 9

regulates vital func

degree of activity is associated with alertness/level of consciousness

reticular formation projects to hypothalamus, thal and cortex

recieves sensory info from ascending tracts (touch and pain), medial vestibular nucleus (vestibular), inferior colliculus (auditory), superior colliculus (vision), medial forebrain bundle (olfactory)

the ventral tegmental area projects dopaminergic neurons to cortex

locus coeruleus projects noradrenergic neurons to cortex

cholinergic neurons project to thalamus - most important for arousal, increase level of activity in cortex via the thalamus

raphe nuclei send serotonergic projections to brain and spinal cord

Question 10

how is the thalamus involved in consciousness *

Answer 10

cholinergic neurons excite individual thalamic relay nuclei = activation of cortex

cholinergic neurons project to intralaminar nuclei - project to all levels of the cortex

cholinergic neurons project to reticular nucleus - allow other thalamic nuclei info to the cortex

Question 11

how is the hypothalmus involved in consciousness *

Answer 11

histaminergic tuberomamillary nucleus projects to cortex

involve

d in maintaining awake state

Question 12

what is the term explaining where consciousness is *

Answer 12

thalamocortical system

Question 13

what is it abount neurons that control consciousness *

Answer 13

unlikely to be location

number - not that simple - cerebellum has loads, but still conscious w/o it

dynamics of neural activity - way they interact and their action overtime as a collective

Question 14

what is integration *

Answer 14

unification of brain activity

brain activity overtime is corralated

Question 15

what is differentiation *

Answer 15

brain activity doing different things - account for the range of things that we experience

Question 16

what are te 2 types of brain processing involved in consciousness

Answer 16

feed forward - subliminal/non-consciousness

top down recurrent processing - conscious access

Question 17

what are the brain networks involved in consciousness *

Answer 17

occipital cortex - visual

frontal and parietal - problem solving

default mode network - idea of self, mind wandering, own thoughts - related to the limbic system - posterior cingulate and precuneus important

Question 18

how can you measure consciousness

Answer 18

use transcranial magnetic stimulation

measure complexity of EEG after TMS - give idea of consciousness

need complexity to have the rich experience

perturbation complexity index - complexity increases wit level of consciousness eg in locked in syndrome similar to being awake

Question 19

what are te neural correlates of consciousness *

Answer 19

minimal neural mechanisms jointly sufficient for any one specific conscious experience

primarily localised to posterior central hot zone tat includes sensory areas

Question 20

what is a coma *

Answer 20

absent wakefullness and absent awareness

unarousable unresponsiveness, lasting>6yrs

• cannot be awakened
• no response to pain ligt or sound
• lack normal sleep wake cycle
• does not initiate voluntary actions

Question 21

what is vegetative state *

Answer 21

wakefulness with absent awareness

preserved capacity for spontaneous or stim induced arousal, sleep wake cycles and reflexive/spontaneous behaviours

complete absence of behavioural evidence for self- or env awareness

Question 22

what is minimally conscious state *

Answer 22

wakefulness wit minimal awareness

severely altered consciousness

minimal but clear behavioural evidence of self or env awareness is demonstrated

inconsistant but reproducable responses above level of spontaneous or reflexive behavior - indicate some degree of interaction with their surroundings

Question 23

cause of locked in syndrome

Answer 23

MND

guillain-barre syndrome

Question 24

what is the area of te brain affected in veg state *

Answer 24

destruction of cortex and hemispheres

intact RAS

Question 25

area of brain affected in LIS \*

Answer 25

in-tact cortex ascending reticular activating system damage to ventral pons

Question 26

area of brain damaged in brain stem death \*

Answer 26

irreversible brain stem damage

Question 27

describe covert awareness in disorders of consciousness \*

Answer 27

although no visible sign of consciousness - pt can thonk the correct answer to yes/no qns - still conscious therefore need to think if we need pain relief or develop a brain-computor interface

Question 28

describe neglect \*

Answer 28

body no longer conscious of other half of body - removed from perception eg cant identify the middle of a line/only draw clock on 1 side higher order than a visual defect sensory neglect - prefer the side tey can percieve, lower order sensory cortex fine but loss of perception of reality higher order

Question 29

describe the interpretation of EEGs \*

Answer 29

delta waves \<4Hz sleep theta 4-8Hz alpa 8-13 B 13-30 normal waking consciousness gamma - 40 slowing is bad (delta and theta) alpha normal when eyes closed - especially from posterior electrodes - posterior dominant rhythm - loss of this is bad used in diagnosis of epilepsy and non convulsive satus (siezures with no convulsions - last for hours or days) waves slow as go through stages of sleep

Question 30

what are the points of glasgow coma scale \*

Answer 30

picture of scale localisation of pain - reach and touch where pain is flexor - arms in extensor - arms out

Question 31

what are the metabolic causes of coma \*

Answer 31

drug overdose hypoglycaemia diabetes - hyperglycaemia the failures hypercalcaemia

Question 32

diffuse intracranial cause of coma \*

Answer 32

head injury meningitis subarachnoid haemorrhage encephalitis epilepsy hypoxic brain injury brainstem stroke

Question 33

hemisphere lesion cause of coma \*

Answer 33

cerebral infarct cerebral haemorrhage - subdural/extradural abscess tumour

Question 34

brainstem cause of haemorrhagic stroke \*

Answer 34

infarct tumour abscess cerebellar haemorrage cerebellar infarct

Question 35

scan of extradural haemorrhage \*

Answer 35

above dura elliptical

Question 36

scan of subdural haemorrage \*

Answer 36

alongside brain - moon crescent

Question 37

describe loss of consciousness in extradural haemorrhage \*

Answer 37

lose immediately - concussion lucid interval where fine lose consciousness again because of rise in intracranial pressure

Question 38

describe diffuse axonal injury \*

Answer 38

head moves eg hemispheres in oppositee dirns - damage to white matter eg corpus collosum see with gradient echo/suseptibilty weighted imaging - black dots show blood next to the white matter tract

Question 39

why do posterior brainlesions affect consciousness \*

Answer 39

compress the brain stem

Question 40

why do bilateral medial thalamic infarcts affect consciousness \*

Answer 40

mess with thalamocortical system

Question 41

dexcribe confusion \*

Answer 41

mental processes slowed inattentive or disorientated difficulty carrying out simple commands or speaking

Question 42

describe stupor \*

Answer 42

only roused by strong sensory stim

Question 43

describe brain death \*

Answer 43

irreversible coma no brainstem reflexes or response to hypercapnia eeg not diagnostic spinal reflexes adn postural movenents might be presnet

Question 44

effect of lesion to extra-striate cortex \*

Answer 44

loss of colour perception

Question 45

effect of parietal lesions \*

Answer 45

lack of awareness in contralateral visual field

Question 46

is the visual cortex essential for consciousness \*

Answer 46

need it to see but visual cortex can respond to stimuli it doesnt detect

Question 47

what is essential for consciousness \*

Answer 47

feed-forward relay from senses to prefrontal and parietal cortex and feedback to sensory cortices content emerges from feedback across brain regions

Question 48

describe EEG throug sleep \*

Answer 48

awake - B wabes drowsy - A N1 sleep- theta N2 - sleep spindles N3 - delta REM - fast and random