lecture 35 Flashcards
How does the brain produce our experience of ourselves and our universe?
- there seems to be a close, possibly complete, isomorphism between the function of the brain and the conscious experiences
- “consciousness is what the brain does”
- in some instances, we can observe with fairly high resolution the “neural correlates of consciousness”
- the problem (the problem) is that this in no way provides an explanation of how the brain produces consciousness
How can there be any sort of awareness or phenomenality?
- this has been termed (by David Chalmers) as “the hard problem”
- is consciousness fundamentally unlike everything else of which we know?
- there seems no way to relate it to any property or process, or any member of the set of all things which aren’t consciousness
- is the study of the brain in relation to consci ousness therefore necessarily confined to the “easy” problem?
- that being the neural events associated with the generation of phenomenality, the physiological or neural correlates of consciousness
What is the chinese room thought experiment?
- chinese writing (characters) comes in to your room
- you use the rulebook and construct more chinese characters (this is an algorithmic process)
- you send those new (chinese) characters our of the room
q. do you understand chinese?
is there more to consciousness than algorithms?
when people understand something they have a conscious awareness/capacity for knowing what something is
there is a difference between a process and a conscious understanding
Can computers be like brains?
2001: a space odyssey
- computer says things like i’m afraid
- is it possible to build a computer like this?
- self-awareness
- is it possible to get a computer that experiences emotion , can be labotomised?
How can there be any sort of awareness of “phenomenality”?
- a contrasting view is that consciousness only seems unqiue, but is in fact nothing more than the result of complex brain activity, as much explicable in terms of the physiology of biological entities as anyother complex and superficially mysterious process
- Daniel Dennett points out that while our intuition that consciousness is special may be powerfully compelling, intuition is a poor guid to the underlying nature of complexx processes
- dennett suggests that we let go of this fondly held, unsupported belief, and set about better understanding the biological processes that generate consciousnesses: the easy, and only, problem
How was life viewed?
- once widely viewed as an irreducible mystery
- vatalism
- metabolism
- élan vitale: the spark of life
- the soul
- “emergent properties”
What has and can neuroscience tell us about consciousness?
some preliminaries:
scope: the “how” (hard) question, not the “where” and “what”
propriety: this is a problem that is squarely the domain of Neuroscience
Naivety: acceptance of the existence of time and space and such as external realities
Why don’t we know how brains generate phenomenality?
three possibilities:
1) current approaches will ultimately succeed, but only with a great deal more investigation
2) current approaches will be fruitful, but progress is impeded for want of some currently undiscovered organising principles
3) the methods of neuroscientists currently pursue are inadequate to address the mech
What sort of information or theoretical insight might be missing?
- for analogy, consider protein function:
- here is the protein’s PRIMARY sturcuture. What does it do?
- need secondary/tertiary structure
biochemistry = space and charge
- detail that’s tricky
- sequence/charge + space = emergent property
- 1º structure + conformation = e.g. catalyst
Is the neuronal electrophysiological data like the primary sequence of a protein: insufficient, on its own, to make sensible the emergent properties?
- is the missing information a higher order structure of neuronal activity (of single neuron spike trains, or structure of an ensemle of spike trains, or a population, or populations)?
- is there another parameter or dimension to neuronal activity, that isn’t captured by neurophysiological analysis, that inextricably binds neuronal computation to the generation of phenomenality?
What might we be missing and what does it matter?
- we may have an incomplete conception of matter, it may have properties that, in suitable arrangements, performs some physical process that generates consciousness
- what good then are all these physiological data?
- e.g. electric fields, electromagnetic structure
- may be fundamental insight missing
- it is hard to imagine that the relevant properties of matter are such that they do not inextricably lie in the specific arrangement of circuits, neurons, glia, synapses, ion channels, currents, electrical fields that is generated by its intrinisc and environmentally imposed pattern of activity
- it has been shown with increasing resolution, that the contents of consciousness are also those extracted by the collective “computational” activity of neurons
- mind and brain may not be identical, in terms of our current conception of the brain, but a full conception is likely to build on, rather than supplant, the current information
- electrophysiological descriptions of brain activity, even if not sufficient, will be essential to understanding the mechanism of conciousness
- we, neuroscientists, should provide a description of what process underlie neural computations, and which aspects of this field are related to consciousness
Why have consciousness?
- an intellectual tradition, and a body of experimental science, has long linked the instinctive behaviours that subserve powerful survival drives, with emotion
- every object that excites an instinct excites an emotion: william james, 1890
What is a comparative/evolutionary approach to consciousness?
- Denton, 2005: the primordial emotiona - the subective element of the instictive behaviour subserving control of the vegetative systems of the body - were the beginnings of consciousness
e.g.
pain is a homeostatic emotion reflecting an adverse condition in the body, such as thirst, hunger, hunger for air, temperature deviation, which demand a behavioural response
interoception connects positive and negative affective experience with adaptive behaviours
c.f. exteroceptive theories of consciousness (e.g. Edelman)
What is interoception in relation to genetics?
- much of the interoception (sensory information coming from within the body) , and the instinctive behaviours and primordial emotions their activity give rise to, must be genetic and “hard wired”
other primordial emotions:
- desire to sleep (after deprivation)
- sense of temperature change
- desire for sex
- thwarting of visceral function
where are these functions regulated - “in the basement” (hypothalamus and brainstem)
- most exteroception is ‘upstairs’
PFC connectivity to sup-cortical and spinal regions
- this highly evolved/cerebral area gets input from enteroceptors/nociceptors
What are new homeostatic afferents in primates?
according to craig, 2005
- assymetric right sided cortical function which is really about awareness of your body
- rarified sense of ‘how are you’
