Lecture 22 - Levels and Dimensions of Consciousness Flashcards
What is meant by levels of consciousness?
Changes in the intensity or degree of consciousness.
Is it that we either have consciousness or don’t?
OR
Consciousness is a spectrum?
If so, what does having more or less consciousness look like?
Is being asleep considered being unconscious?
yes. Although there is evidence of consciousness during sleep.
When coming up with a way to measure consciousness, what is one of the key things to take into consideration?
Consciousness can still exist with impaired sensory or motor output networks. Therefore, we cannot rely on evidence of consciousness that needs to go through these networks, such as “squeeze my hand if you can hear me”.
In an experiment that looked at fMRI imaging of brains in healthy people as well as those in non-responsive state, what did they find when they asked participants to imagine playing tennis and walking through their house?
They found that similar regions were active, suggesting that the non-responsive person could hear and process the task information and engage in the task, even though they were otherwise seen as non-responsive.
Is level of consciousness correlated with amount of neural activity or brain synchrony?
No.
Those under anethesia can have a lot of neuronal synchrony, even though consciousness is lost.
Are highly complex patterns of brain activity associated with greater levels of consciousness?
What grand theory of consciousness does this support?
Yes.
Integrated Information Theory.
What is one of the ways levels of consciousness are currently measured?
By measuring the complexity of brain activity using EEG.
It is purported that those with higher levels of complexity in their brain activity are more conscious. Under a certain level of complexity people are considered to be unconscious.
This has been used to determine whether patients are conscious or not when they are in a coma or non-responsive state.
The measure of complexity is out of 1 and the unsconcious threshold is considered to be 0.38. Having said that, those who are above this, even by a margin are considered to be conscious. If there was slightly less complexity they would be considered unconcious.
Potentially brings up many ethical concerns.
In a study done by Olivia Carter looking at brain activity complexity as measured by EEG, what did they find when people were studying?
Brain activity complexity went down. Are we less conscious when we are very focused on something. Likely not. The theory is likely far too simple to be used as a measure of consciousness.
What is one of the key brain areas associated with consciousness?
If there are even small lesions to this area there can be radical alterations to consciousness.
The Thalamus.
Has deep brain stimulation of the thalamus jump-started consciousness in those who have been in comas?
Yes.
In an experiment on mice that looked at the effect of anaesthesia and neuronal synchrony of level 5 neurons in the cortex that connect to the thalamus, what did they find?
Anaesthesia leads to the synchrony of neuronal activity of level 5 neurons in the cortex that connect to the thalamus.
Stimulating these cells to have them fire in synchrony causes mice to go unconscious.
What are some of the key ethical concerns around a brain activity measure of consciousness?
What does it mean for certain people to be more or self ‘conscious’? How would that inform healthcare choices etc?
