Lecture 9 - Consciousness pt. 3

Question 1

Consciousness mismatches

Answer 1

We’re not conscious of material reality
Real world vs. senses vs. processing (!!) vs. awareness

Everything gets filtered through senses and processed into something else
Never directly touching the atoms of anything real
You’re not conscious of material reality
Never the “pure” thing

Another Problem: Cartesian Theatre
Higher-order perception
as if there’s a little guy in your head watching you do things
watching yourself perceiving things
Homunculus (idk why written)

Question 2

Dennett: Multiple Drafts Model

Answer 2

Never aware of something directly, always aware through several layers of processing

Multiple drafts model:
Different systems in your brain are editing these data streams and making changes to how you perceive things
Everything processed in some way first, but when stability … fame
Fame = when something reaches your awareness
Fame = Longer term process
Link with GWT

“Draft”
● Multiple versions of one stimulus in one “stream”
● Stabilization + importance → awareness

Summary:
Dennett: Multiple Drafts Model - Unconscious streams, sometimes reach “fame” when stable

Question 3

David Eagleman: Democracy of Mind

Answer 3

Wrote ‘‘Incognito’’

Motor cortex activity rises >1s before awareness
Your brain makes a decision before you do
Is free will real?

Competing systems
Multiple streams at the same time
Similar to pandemonium theory
One stream “yells” (pick me!) loud enough to be brought to awareness

● Redundancy - each stream processed by multiple competing systems
● Competition - cf. Pandemonium theory
● Emotional + Rational processing (cf. Freud, cf. Kahneman) “team of rivals”

Summary:
○ Eagleman: Democracy of Mind - Redundant, competitive streams/modules, emotional/rational

Question 4

Integrative Information Theory (IIT)… Giulio Tononi

Answer 4

Example with plant: Phi of 2 (2 dependent systems)
If you have water, fertilizer and a plant
If you cut water out, fertilizer is unaffected but plant is
If you cut fertilizer out, water is unaffected but plant is
So there are 2 dependent systems: water and plant and fertilizer and plant
Phi of 2

Phi would correspond to consciousness (link a bit unclear…)
Consciousness would be parts of brain relying on information from each other (phi)
-interconnectedness of systems in your brain
Panpsychism = can apply to everything. Planets could have consciousness?.
Slapping a random number on it… what does this have to do with consciousness… kinda all made up
Just doing the plant thing takes a long time… imagine for a human??? Pretty impossible
But in theory, a sandworm would have a smaller Phi, then a cat, a human and then a planet

IIT - Criticism
● Panpsychism
● Hard to calculate
● Possible to “hack”
● “Itʼs just your opinion, dude”

Summary:
○ Tononi: IIT - Measure how many dependent subsystems → Φ

Question 5

Brain imaging

Answer 5

Types:

Structural:
-Shows anatomy
-Used for tumors, strokes, lesions, etc.

Functional:
-shows blood flow/electricity
-used during experiments
-(also diagnosis)

CT/CAT (Computed Axial Tomography)
If see bones highlighted in white, probably CT scan
CT uses X-rays

MRI (Magnetic Resonance Imaging) (structural)
If skin and wet tissue are white, probably an MRI scan
Signal time scan
Shooting radio waves… but only hydrogen atoms respond to them… creates an excitation
MRI very expensive

CT vs. MRI
CT:
-better spatial resolution
-cheaper
-faster (around 1 min)
MRI:
-better contrast
-slower (10-40 min)

Question 6

Other brain imaging

Answer 6

fMRI (Functional Magnetic Resonance Imagery)
=multiple scans over time
fMRI images are brighter, not darker where activity happens. For an explanations, please have a look at the updated slides
Brain areas that are active do indeed take up a lot of oxygen.
But thatʼs not whatʼs usually depicted in fMRI images. When blood gets doxygenated
from brain activity, a lot of new oxygen-rich blood rushes into that area. As a results, the
image is BRIGHTER there, not DARKER.

Positron Emission Tomography (PET)
Working areas will absorb glucose, will glow (from radioactivity)
Not cheaper than fMRI (600-1000$ per hour of experiment)

fMRI vs. PET
fMRI:
-Better spatial + temporal resolution
-longer
-expensive
-loud
-no radioactivity
PET:
-fast, quieter
-could get superpowers?
-expensive too

Electroencephalogram (EEG)
Ex: seeing when person falls asleep
Measures brain waves
Doesn’t pick up signals very deep, not very far from skull
● Fast, cheap, safe
● Direct relation to brain activity
● Garbage spatial resolution

What’s missing?
Something that can measure your entire nervous system at the same time
Not just the brain

Question 7

Summary of brain imaging

Answer 7

○ Structural: CAT/CT, MRI
○ Functional: fMRI, PET, EEG

Question 8

Summary

Answer 8

● (More) Consciousness Models
○ Dennett: Multiple Drafts Model - Unconscious streams, sometimes reach “fame” when stable
○ Eagleman: Democracy of Mind - Redundant, competitive streams/modules, emotional/rational
○ Tononi: IIT - Measure how many dependent subsystems → Φ
● Brain Imaging
○ Structural: CAT/CT, MRI
○ Functional: fMRI, PET, EEG
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