Lecture 14- The Neural Basis of Consciousness Flashcards
What are the three important aspects of consciousness to consider?
- Sentience (subjective experience: what is it like to experience something e.g. pain, the colour red?)
- Self-knowledge (Here I am, me……meta-awareness, I am situated in the world and separated from other organisms)
- Access to information (ability to report on the content of some of my brain processing but not all)
What issue presents when thinking about the consciousness of other animals?
- How can we know about the experiences of another animal?
- Is an animals version of self-awareness/ consciousness the same as us?
What does the New Caledonian Crow show about tool use behaviour?
- Intelligent behaviour
- May indicate some self-awareness or consciousness
What about tool assembly in birds? What does this show?
- Shows the ability to plan
- Birds need awareness of current location and things in relation to them
- Again points to the fact that we as humans may not be the only ones capable of self awareness
What does the rescue behaviour of trapped ants show:Chittka and Rossi (2022)? What issue does this raise in terms of how we view complex behaviour?
- Complex behaviour
- Ants have very little neurons so how are they capable?
What is an alternative to thinking about the ant rescue behaviour that doesn’t require complex behaviour?
- have been learned through trial and error?
- have been shaped up through previous experience?
- are part of a hard-wired repertoire of behaviours (evolution)?
What does egg retrieval in the greylag goose indicate?
- Would think this is an example of complex behaviour in a non-human animal (and non primate)
- On further inspection the ‘egg’ doesn’t even to be white or egg shaped
- So instead of a hugely complex behaviour it might just be an Innate response to having something outside of the nest which triggers the animal to roll the object back into the nest
What is the classic test of self-awareness by Gallup (1970)?
- Mirror self awareness
- Individual (typically baby or also has been done with elephants) has mark on face
- See if the participant touches their own nose or laughs at the mirror
- Touch own nose indicates self-awareness, they know the mirror is showing themself
Does the mirror test necessarily have to show self awareness? What is an alternative hypothesis?
- Could simply be a matching of kinesthetic sensation to visual perception (associative process)
- Proposed by Mitchell (1993)
How to solve MSR without self-awareness:
- Look at image in mirror
- Be familiar with mirror image
- Move arm and discover that kinaesthetic sense of arm movement corresponds to visual change in mirror
- Be aware that image has changed (red dot).
- Move arm or trunk so that object (finger) in mirror touches red dot.
How has human memory been structured into conscious and non-conscious components?
- Memory is spilt in implicit (Procedural) memory and explicit (declarative) memory
- Implicit memory: Skills, priming, habit
- Explicit memory: episodic, semantic
Explicit memory is what is conscious
How did Hampton (2001) provide insights into the conscious memory in Rhesus monkeys?
-Study phase
-Delay interval
-Choice phase: Press one option to have a memory test which will provide a nice reward if you are correct, Press the other option to get
a food pellet (guaranteed but ho-hum)
-The second is the safe option. For the memory test you are either forced or choose it. If you choose to take the memory test and are not forced then would expect greater accuracy. This is what was found with Rhesus monkeys
-This would indicate some level of self awareness in Rhesus monkeys as they they aware of their level of knowledge
What was found in Hampton (2001) in relation to the probability of declining tests after variable delay intervals?
- With long delay monkeys are less likely to make choice of taking test.
- This shows awareness that memory might not be as strong (matched accuracy decline)
What is meant by the term: Neuronal Correlate of Consciousness (NCC)?
-It is probable that at any moment some active neuronal
processes in our head correlates with consciousness, while
others do not; what is the difference between them?
-This neuronal process is referred to as the neuronal correlate of consciousness.
What areas of the brain are invovled in modulating consciousness?
- Reticular formation + thalamus= when these regions is activated tend to be conscious
- Raphe nuclei + suprachiasmatic nucleus= associated with sleep
- Different times of day means these areas are less or more active
What are the three general states of consciousness?
- Awake
- Drowsy
- Sleep
In a drowsy state what is the difference between Hypnogogic and Hypnopompic states?
- Hypnogogic= When going into sleep
- Hypnopompic= When waking up
What is locked in syndrome?
- fully conscious but unable to move
- damage to ventral part of pons
What is a Minimally conscious state?
e.g. fixation, response to simple command – reduced activity
in cortex
What is unresponsive wakefulness syndrome?
-Open eyes but only reflex behavior: damage to cortex and/or thalamus
What is an experimental approach used to understand the NCC?
-The use of bistable percepts in which a constant retinal stimulus gives
rise to two percepts alternating in time, as in a Necker cube.
-Look at corner see it switch from being at the front of the cube to the back
-The key notion is that the stimulus is stable but the perception is not
As opposed Necker cube what is another bistable task?
- Binocular rivalry: Put hand up so one eye is seeing one grid and the other eye seeing the other. Will see only one grid and then will switch to the other
- Compare brain activity during rivalry (perceptual changes) with activity when stimulus is actually changed.
- Rivalry demonstrates fluctuating conscious experience despite fixed physical stimulation(won’t see both).
What does the brain activity in the binocular rivalry task show? What different areas of the brain are responsible for NCC and introspection?
-Neural loci that were more activated at the moment of a subjective report of transition (i.e., button press) during rivalry trials compared with replay trials.
-Proposal: difference reflects changes in conscious awareness
not driven by stimulus change. But what part is introspection and action?
-When the reporting requirement is removed contrast studies suggest that parietal and occipital areas are involved in the NCC for visual stimuli
-Suggests frontal activation relates to introspection and action while occipital and parietal with NCC
What did Schroter et al (2012) investigate?
- When we are anaesthetised, consciousness fades yet the brain remains active. Could this be examined?
- Found that there was reduced network connectivity both short range and long range during propofol-induced loss of consciousness
What was done to investigate the difference between sleep and wakefulness?
-Used Transcortical magnetic stimulation (TMS)
-Researchers recorded TMS-evoked brain responses while six
subjects, lying with eyes closed on a reclining chair, progressed from
wakefulness to non-REM sleep.
-TMS was targeted to the rostral portion of the right premotor cortex.
-Found that as the individual goes sleep there is an increase in the magnitude of TMS and once asleep are less likely to have oscillations.
-As you go to sleep the ability of the brain to send info over long range decreases. Loses ability to integrate data across the cortex (processing= local).
What are the implications of the evidence to do with connectivity in Massimini et al Science (2005) 309:2228?
- Evidence for a breakdown of long-range effective connectivity during non-REM sleep.
- Thus, an impairment in the ability to integrate information may underlie the fading of consciousness in non-REM sleep early in the night.
Is brain activity during lucid dreaming different to that during the non-lucid state?
- Increases in BOLD signal in Lucid REM as opposed to non-Lucid REM Sleep
- Functional connectivity difference during rest: Lucid - non-Lucid dreamers
