Task 1 Flashcards
Fundamental theory of consciousness
Theory that contains principles of the relationship between first- and third-person data (e.g. that certain types of experience go together with certain brain processes or certain types of information processing).
Neural correlate of consciousness (NCC)
The neural system or systems primarily associated with conscious experience
Pre-experimental bridging principles
Criteria that we consider in systems to say (1) whether or not they are conscious now, and (2) which information they are conscious of, and which they are not.
Principle of verbal report
A bridging principle which says that if information is verbally reported, it is conscious
Principle of reportability
When information is directly available for verbal report, it is conscious.
Prinicple of Global Availability
When information is available for global control in a cognitive system (allows other ways of report that are not verbal), then it is conscious.
Implications of the rational reconstruction of global availability
- NCC either subserves global availability in the brain or it is a symptom of global availability
- Knowledge about the NCC will explain global availability in the brain and will isolate the processes that underlie consciousness
- There will be many NCCs because there will be many mechanisms of global availability
- A consciousness module may be found to exist
- Discovering a NCC using this methodology does not mean that we have discovered a consciousness meter
Vegetative state
- A disorder in which patients who emerge from coma appear to be awake but show no signs of awareness
- High rate of diagnostic errors (~40%)
Detecting awareness in the vegetative state (Study 1)
Study (Owen et al.)
- Woman in vegetative state, present sleep-wake cycle
- fMRI is used to measure the woman’s neural responses during the presentation of spoken sentences
- Speech-specific activity was observed in the middle & superior temporal gyri, equivalent to that of healthy volunteers listening to the same stimuli
- Ambiguous words produced an additional response in a left inferior frontal region
Detecting awareness in the vegetative state (Study 2)
Study (Owen et al.)
- Woman in vegetative state was given spoken instructions to perform 2 mental imagery tasks at specific points during a fMRI scan
- Significant activity in parahippocampal gyrus, posterior parietal cortex, and lateral premotor cortex
- Her responses were indistinguishable from those observed in healthy volunteers
Minimally conscious state
Describes patients who recover from a vegetative state, but not fully. They show inconsistent, but reproducible signs of awareness, including the ability to follow commands. However, they remain unable to communicate interactively
Willful modulation of brain activity in (maybe) vegetative patients
Study (Monti et al.)
- 54 patients with severe brain injury (23 in a vegetative state & 31 in a minimally conscious state) underwent fMRI in order to evaluate their performance on motor & spatial imagery tasks.
- Motor imagery task: Patient is instructed to imagine standing still on a tennis court and to swing an arm to “hit the ball” back and forth to an imagined instructor.
- Spatial imagery task: Patient is instructed to imagine navigating the streets of a familiar city or to imagine walking from room to room in their home & visualize all they would see if they were there
- Communication task: Imagining the two scenarios as “yes” and “no” responses. One patient was able to do it
- 5 out of 54 patients (4 in a vegetative state, all 5 with a traumatic brain injury) could willfully modulate their brain activity
Obstacles to developing first-person methologies (like Introspection)
- The idea that introspecting an experience changes the experience
- The impossibility of accessing all of our experience at once
- The possibility of illusions
