17 Consciousness Flashcards
What are the 2 THEORIES of consciousness?
Dualism
Naturalism
What philosopher believed in Dualism?
Descartes - Mind-Body dualism
Define Descartes’ DUALISM
Mental/Physical world exist in 2 SEPARATE realms
- Res extensa - PHYSICAL world
- Res cognitans - MENTAL world
What did Descartes think was the INTERFACE between the physical and mental realms?
Pineal gland
Define Naturalism
Mental events ARISE FROM brain processes
NO distinction between mental/physical realms
Define perception WITHOUT awareness
Processing information from eyes WITHOUT processing that information to UNDERSTAND it?
(Perceive without knowing it)
Explain a LESION that proves the existence of “Perception WITHOUT awareness”
“Blindsight” = lesion in V1
= “blind” in part of visual field
= “Cortical blindness”
The extend of cortical blindness in “Blindsight” depends on?
EXTENT of V1 dmg
Name 2 famous patients who had Blindsight
DB
GY
What SYMPTOMS did DB and GY have?
BLIND for part of visual field, but COULD respond to visual info with NO AWARENESS of what they were seeing
What happened when Blindsight patients were subjected to “Forced-choice responding”?
Accurately “guess” line orientations and striped vs grey patches in the “BLIND” area
= INSIST they see nothing
= responses are PURE guesses
Why do Blindsight patients still ACCURATELY “guess” things in their “blind” area?
Some visual pathways that BYPASS V1
= allows some “vision” in the “cortically blind areas”
What is a key example of “Perception without awareness” in all NORMAL people?
Semantic Priming
Define Semantic Priming
If shown words of RELATED MEANING (eg. Bread + Sandwich)
= FASTER response to target word
What is the 3 step PROTOCOL for semantic priming?
- PRIMING word shown briefly (Bread)
- Scrambled letters shown briefly
- TARGET word shown briefly
= people respond FASTER to related words
What does the Semantic Priming effect prove?
Even NORMAL people show “Perception without Awareness”
Perceived priming words WITHOUT perceiving them
What research technique was used to compare BRAIN activity during CONSCIOUS vs NON-CONSCIOUS perception?
Neuroimaging
What did neuroimaging show for CONSCIOUS perception of a VISIBLE word?
WIDESPREAD activity
= “Cerebral ignition” (information becomes GLOBALLY available”
What model comes from “Cerebral Ignition”
Global Neuronal Workspace model
= “SHARED workspace” accessible to ALL brain areas
What does neuroimaging reveal about NON-conscious processing when an INVISIBLE word is shown?
SPECIALISED areas of visual pathway ONLY
= restricted by limited information from specialised processors
(NOT whole brain activation)
What did Chalmers come up with?
EASY vs HARD problems of consciousness
Name Chalmers’ “EASY” problems of consciousness
Simple distinguishing of CONSCIOUS vs NON-conscious
- Perception
- Learning (Iowa Gambling Task)
The EASY problems of consciousness can be STUDIED using…
Cognitive NEUROSCIENCE methods
Accessible using technology, measurable
What is Chalmers’ HARD problem of consciouenss
“Qualia”
= Subjective experience of the individual
What is Chalmers’ THEORY about consciousness?
Consciousness as a “FUNDAMENTAL FEATURE” of the universe
= cannot be analysed into anything more basic
= cannot be explained by BASIC neural/physical processes
= most simple building block element?
Who DISAGREES with Chalmers?
What does he say about Chalmers’ theory?
Dennett:
Chalmers appeals to our INTUITIONS but our intuitions can be UNRELIABLE
List 5 ways in which STATES of consciousness can be ALTERED (acronym)
SHNDD (‘Shinned so hard you lose consciousness’)
- Sleep
- Hypnosis + meditation
- Neuropsychological syndromes
- Drugs + alcohol
- Disorders (coma, vegetative)
STATES of consciousness are STUDIED using…
What is this?
EEG = electroencephalography
Small electrical charges due to brain activity measured using ELECTRODES
What PATTERNS are seen on EEGs?
WAVES that follow CYCLIC changes
List the 4 types of EEG patters from LARGEST to smallest waves
Explain what STATE of consciousness each wave represents
BATD β - normal WAKING, alert α - DROWSY, meditation θ - LIGHT sleep ∆ - DEEP sleep
How many STAGES of SLEEP are there?
5
What happens in the FIRST stage of sleep?
What is it CALLED?
For HOW LONG does it last?
Hypnogogic sleep (~5 min)
= breathing DEEPER + more regular
= EASY to awaken
= HYPNIC jerks
What kind of WAVES does stage 1 sleep show on an EEG?
THETA (light sleep)
What happens in the SECOND stage of sleep?
For HOW LONG does it last?
Stage 2
= ~20 min
= Relatively easy to awaken (but KNOW they were asleep)
= SLEEP SPINDLES on EEG
What are ‘Sleep Spindles’ on an EEG?
SPIKES followed by BURSTS of activity
What happens in the THIRD + FOURTH stages of sleep?
What is it CALLED?
“SWS - Slow Wave Sleep”
= DEC breathing + HR + body temp
= HARD to awaken
What kind of EEG waves are seen during SWS
DELTA waves (deep sleep) = slow, high amplitude waves
What is a VISIBLE chracteristic of stage 1 sleep?
Hypnic jerks
What is a EEG characteristic of stage 2 sleep?
Sleep spindles
What is the 5th stage of sleep?
REM sleep
= Rapid Eye Movement sleep
What happens in the REM leep?
WHEN does it begin?
REM sleep = ~90 min after falling asleep = FAST + IRREGULAR breathing, HR = Genital arousal = HARDEST to awaken = DREAMING
What does EEG during REM look like?
Therefore, what is REM also called?
Resembles WAKING pattern
= “Paradoxical” sleep
How does sleep change throughout the night?
CYCLES throughout the night
- SWS dominates EARLY
- REM dominates LATER
Name 4 DoC (Disorders of Consciousness) + acronym
CVML
- Coma
- Vegetative state
- Minimally-conscious state
- Locked-in syndrome
Explain COMA
- Completely unresponsive
- NO wakefulness
- Closed eyes
Explain Vegetative state
- Wakefulness (eyes open)
* Reflexive behavior
Explain Minimally-conscious state
- Wakefulness
- SOME non-reflexive behavior
- SOME ability to follow COMMANDS
Explain “Locked-in Syndrome”
Awake/conscious but CANNOT make responses
What technique is used to detect/confirm CONSCIOUSNESS in DoCs?
Neuroimaging
Explain how neuroimaging may be used to detect consciousness?
Ask patients to imagine playing tennis
= similar excitation patterns in CONTROL + PATIENT
What is another TECHNOLOGY which has improved DoC confirmations and Tx?
BCIs = Brain Computer Interfaces
What does BCI allow us to do?
Allows COMMUNICATION + Tx tailoring
Give examples of BCIs
EEG
fMRI
