Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroscience > L56 Consciousness > Flashcards

L56 Consciousness Flashcards

1
Q

define consciousness

A

the ability to be aware of oneself and ones place in the environment

the ability to respond appropriately to environmental stimuli

*easy to define, but no one knows how it works

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does consciousness depend on?

A

synchronization of cortical neurons that fire around 40Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does consciousness result from?

A

important functions of brain activity

  • memory
  • learning
  • distinguishing self from non-self
  • re-entry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define re-entry

A

the recursive comparison of info by different brain regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

where is the re-entry mechanism located?

A

in circuits of the thalamocortical system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define coma

A

nonsleep, loss of consciousness that (unlike syncope) lasts for an extended period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the levels of unconsciousness?

A
  • lethargic
  • obtunded
  • stuperous
  • comatose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define lethargic

A

pt can be fully aroused

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define obtunded

A

pt cannot be fully aroused

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

define stuporous

A

sleep like status

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

define comatose

A

no purposeful response to stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does the brainstem play an important role in?

A

condition of consciousness
attentive vigilance
wake-sleep rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

lesions to what can impair consciousness?

A

thalamus
midbrain
or both cerebral hemispheres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe the brainstem and its link to consciousness

A
  1. Cells of the midbrain (reticular formation) receive ascending info from the spinothalamic track and other
  2. They are projected via 2 branches to higher cortical centers
    - To the thalamus→ activating and modulating
    thalamic relay nuclei and intralaminar nuclei
    - To the lateral hypothalamic area→ which is joined by ascending output from hypothalamic and basal forebrain cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

define the transmission mode

A
  • resting potential is near firing threshold
  • cholinergic input from pons and basal forebrain is present
  • EEG shows DEsynchronized pattern - LOW voltage, HIGH frequency

wakefulness and awareness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define Burst mode

A
  • neurons hyper polarized by inhibitory GABA from reticular formation input
  • EEG shows Synchronized wave patterns - HIGH voltage, LOW frequency

deep sleep and coma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is coma?

A

A deep state of unconsciousness; unable to move or respond to environmental stimuli

Raw definition→ not opening eyes, not obeying commands and not uttering understandable words

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the common causes of coma?

A

Commonly caused by head injury or complications to another disease (ie: brain tumor or ↑ICP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what brain structure is involved in Vegetative state?

A

cortex/higher centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe Vegetative state

A

-A complete loss of higher brain function (cortex) however maintain breathing and circulatory functions
-Spontaneous movements can occur such as eye opening to painful external stimuli but are unable to
respond to commands, to speak or respond meaningfully to environmental stimuli
-Pt may cry, grimace or laugh but this is not the result of them interpreting and responding meaningfully.

21
Q

what brain structure is involved in brain death?

A

all brain including the brainstem

22
Q

describe brain death

A

Denotes the irreversible loss of all brain functions
determined by
-No electrical brain activity (isoelectric EEG)
-Absence of brain→ no movement, response to stimuli, breathing or brainstem reflexes

23
Q

what are common causes of brain death?

A
  • Anoxia (suffocation; can be drug, respiratory disease, etc)
  • Ischemia (vascular occlusion)
  • Intracranial Hemorrhage
  • Trauma
  • Brain Tumors
  • ↑ICP and uncal herniation
24
Q

what brain structure is involved in Locked-in-syndrome

A

pons

25
Q

describe Locked-in-syndrome

A
  • Blockage of basilar artery causing massive infarction to pons
  • Causes total paralysis of voluntary muscle except for vertical eye movement muscles and opening lid
  • Pts are fully aware but cant move and communicate via vertical eye movements and opening the eyelid
26
Q

what causes loss of consciousness?

A
  • damage to the reticular formation in the midbrain
  • damage to either branch of the ascending arousal system
  • impairment of thalamus
  • bilateral impairment of the cerebral hemispheres
27
Q

what is the Glasgow coma scale

A

scored between a 3 and 15

28
Q

what 3 parameters are evaluated in the GCS

A

best eye response
best verbal response
best motor response

29
Q

what is the criteria to grade best eye response?

A 
(4)
1 - no eye opening
2 - eye opening to pain
3 - eyes opening to verbal command
4 - eyes open spontaneously
30
Q

what is the criteria to grade best verbal response?

A 
(5)
1 - no verbal response
2- incomprehensible sounds
3 - inappropriate words
4 - confused
5 - orientated
31
Q

patients who score less than or equal to 8 on GCS are what?

A

90% in coma

32
Q

patients who score greater than or equal to 9 on GCS are what?

A

not in coma

33
Q

what is the critical score of GCS?

A

8

34
Q

what score describes moderate severity of the GCS

A

9-11

35
Q

what score describes minor injury of the GCS?

A

12-15

36
Q

where is the lesion associated with Cheyne-Stokes respirations?

A

forebrain lesions

37
Q

where is the lesion associated with apneusis (inspriatory cramps) respirations?

A

lesion in pons

38
Q

where is the lesion associated with hyperventilation respirations?

A

lesion in midbrain

39
Q

where is the lesion associated with ataxic breathing respirations?

A

lesion in lower pons/upper medulla

40
Q

what damage is associated with decorticate posturing?

A

damage to upper midbrain (bilteral)

41
Q

what damage is associated with decerebrate posturing?

A

damage to upper pons or lower midbrain (bilateral)

42
Q

with respect to the pupillary light response, what does small reactive pupils indicate?

A
  • diffuse forebrain impairment (metabolic encephalopathy)
  • pontine injury
  • sedative drugs (opiates)
43
Q

with respect to the pupillary light response, what does mid positional pupils and loss of response indicate?

A

-structural injury (almost always) damage of CN III at level of midbrain

44
Q

with respect to the pupillary light response, what does unilateral pupillary dilation indicate?

A
  • injury of CN III at the exit of brainstem

- unilateral compression (aneurysm of post. communicating a., tumor, increased ICP –> uncial herniation)

45
Q

with respect to the pupillary light response, what does large, unreactive pupils indicate?

A

pressure in pretectal area (pineal tumor)

46
Q

with respect to oculomotor responses, describe metabolic encephalopathy?

A
  • dolls head maneuver - eyes roll counter head movement

- cool water in ear - eyes turn to same side = brainstem intact

47
Q

with respect to oculomotor responses, describe a right pontine lesion?

A

Dolls Test

  1. Head to right→ normal (eyes to left)
  2. Head to left→ no movement at all

COWS

  1. Cold in right→ no movement
  2. Cold in left→ normal (eyes to left)

gaze paralysis to the right, because right PPRF and /or right CN VI is lesioned

48
Q

with respect to oculomotor responses, describe a midbrain lesion?

A

Dolls Test

  1. Head to left→ right eye normal but left is unresponsive
  2. Head to right→ left eye normal but right is unresponsive

COWS

  1. Cold in right→ right eye normal but left is unresponsive
  2. Cold in left→ left eye normal but right eye is unresponsive

*This lesion involves both occulomotor nuclei causing loss in Medial Rectus, thus loss of aDduction

Neuroscience (54 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions