L2 - Brain Basis of Consciousness

Question 1

What is the easy problem?

Answer 1

• Mapping consciousness onto the brain
• How to find correlation between correlation between brain activity and the presence/absence of conscious experience
• As well as the contents of conscious experience

Question 2

How are paradigms designed?

Answer 2

• Vary conscious experience while keeping everything else unchanged
• Research ppts are asked to introspect and report their conscious experience, with brain activity is recorded
• So we can study localisation of consciousness and find out what brain regions are essential for consciousness

Question 3

Is mapping enough?

Answer 3

No, you cannot generate consciousness

Question 4

What is the overall hard problem of consciousness?

Answer 4

• Understanding the nature of conscious experience to then build a brain to generate consciousness
• What is structurally unique about the brain that allows it to generate consciousness
• Conscious experience comes from fundamentally different responses e.g auditory and vision but neurones only have one activation for, how does this one activation lead to multiple conscious experiences

Question 5

What is the structure of the brain?

Answer 5

• Anterior cortex: Evolutionarily young related to behaviour and intelligence to do with cognition and motor and language
• Posterior cortex = evolutionarily old = visual, somatosensory, audition, olfaction regions

Question 6

Which parts of the brain are responsible for consciousness?

Answer 6

• Anterior = responsible for consciousness as it is advanced so preserved for limited species
• Posterior is responsible for consciousness as it is widespread as the feeling of life

Question 7

How do we measure consciousness during sleep?

Answer 7

• Vary conscious experience
• Keep sensory inputs the same
• Disentangle neural correlates of consciousness from other neural correlates

Question 8

Why can we measure when people are asleep?

Answer 8

• Brain is disconnected from env on sensory input side
• Brain receives no memory from env
• Same for behavioural output to the env in NREM sleep (REM sleep involves eye constant movement)

Question 9

What is a serial awakening paradigm?

Answer 9

• Wake up research ppt every few mins
• Ask ppt to report presence/absence of conscious experience, contents of conscious experience and the features of the conscious experience
• Ppt go back to sleep and wear EEG to record brain activity for the entire night

Question 10

What were results about consciousness during sleep?

Answer 10

• Looking at dream experience vs no experience and then figure out which brain regions are active
• Dream occurs in 34% of NREM sleep but 77% in REM sleep
• Posterior cortex correlates with dream experience

Question 11

How to study consciousness during wakefulness?

Answer 11

• Binocular rivalry: two eyes receive completely different images
• Visual input and behavioural output stay unchanged BUT visual experience changes and when this happens you press a button (behavioural output is not associated with consciousness)
• Posterior cortex correlates with visual experience instead of visual input

Question 12

How are neurons key in consciousness?

Answer 12

• Neural networks are optimised for signal transmissions such as the complex network
• Neural networks that have very limited signal transmission capacity such as lattice network are deemed irrelevant for consciousness (one neuron links to one other)
• The all-to-all network is known for its fast speed of signal transmission is associated with loss of consciousness

Question 13

Why does the conventional assumption fall short?

Answer 13

• Why singular act of neural activation and signal transmission can yield fundamentally distinct forms of conscious experiences
• Think about the inherent meaning of neural activation and signal transmission

Question 14

What is the new theoretical framework for neural activation?

Answer 14

• Extends beyond act of activation and lies in causes and effects of the activation
• The dendritic connectivity of a neuron shapes causes of activation and axonal connectivity shapes effects of its activation
• Singular neural activation can generate different meanings and forms of consciousness DEPENDING on what are the actual vs potential causes and effects of activation
• Not all neural networks can ensure diversity in causes and effects and at times, the ability to do so is inversely related to the networks speed of signal transmission

Question 15

How does the all-to-all neural network not work?

Answer 15

• All connect to all
• All carry the same meaning
• No diversity in cause and effect

Question 16

Why does the lattice network work?

Answer 16

• Each neuron has a unique profile of connectivity
• When activated = distinct profile of causes and effects determined by cortical location of neuron and its cortical distance from other neurons
• Results in out form of consciousness
• Diff forms of neural networks = diff consciousness

Question 17

Diff in structure between anterior and posterior cortex for consciousness to be in the latter?

Answer 17

• Neural networks in P are more diverse in cause/effects

Question 18

What is consciousness/un during sleep?

Answer 18

• Consciousness before they were awoken = low delta wave = neurons show constant up state = wakefulness = neural connectivity is taking effect possessing ability to construct causes and effects
• Unconsciousness before awoken = high delta wave = neuron alternate between up/down states = neural connectivity loses effect, lacking ability to construct cause and effect.