Lecture 5: EEG methodology and attention and consciousness Flashcards
Describe the procedure of a study described in the book which attempts to study unconscious incentives
Participants are given a thing to squeeze to win money depending on how hard they squeeze. There is either a penny or a pound at stake. They are not told, instead there are shown either a penny or a pound masked by an image containing a bit of both. The time that the stimulus was presented was also varied. fMRI scans were carried out during this study.
Describe the results of the unconscious incentives study
The researchers found activation in the globus pallidus of the reward circuit in the absense of consciousness (when masked, 17ms) which was stronger to a penny than to a pound.
What was the research question of the research article ‘Unconscious activation of the prefrontal no-go network.’
Can unconscious processing occur at the level of the prefrontal cortex of the brain?
Why was this research article relevant at the time?
Consciousness was associated with the more frontal, higher level areas. Most people believed humans were the most developed and we also had the largest prefrontal cortex.
Describe the procedure of this research article
Subjects fixated on a cross, a signal of either a square or a diamond was then shown followed by a meta-contrast mask of (funny circle thing made up of lines that could either contain a square or a diamond.) Either the signal was displayed for 16.7ms and the mask for 233ms or the other way around so the mask was masked :P.
This proceded in a no-go trial where participants were instructed to not respond if they seen a square stimulus. Since participants only perceived a square when it was made visible, they typically only had a no-go response in that condition. Conscious No-Go inhibition and unconscious no-go inhibition data was collected. fMRI results were also gathered during the task.
How did the researchers check that the squares and diamonds weren’t perceived?
Participants carried out trials of only the unconscious trials and were told there was always a square or a diamond. Participants then pushed a button to decide in a forced choice design. Participants were correct at about a 50% rate.
What were the main results of this research article?
Participants were slower to respond to an unconscious no-go stimulus than to an unconscious go signal. fMRI results showed a widespread fronto-parietal network that was activated during conscious inhibition trials. Much less activation was observed in the non-conscious inhibition trials but activation was observed in the right interior frontal cortex (IFC) and the pre-SMA, both involved in this fronto-parietal network.
What conclusions can be drawn from this research?
behavioural results- inhibition occurs somewhat even when the inhibition signal is not consciously perceived
fMRI results: You can get frontal activation in the absence of conscious awareness, suggesting that at least pure activation of frontal cortex does not lead to consciousness- something else is needed.
What have similar studies to this found regarding this topic, as discussed in the book and the lecture?
All brain regions can be activated in the absence of consciousness. Unconscious processes usually lead to more local activity patterns while conscious processes lead to more global activity patterns
Summarise the information thus far according to the lecturer
Information can be processed unconsciously by the brain and can activate several levels of processing. Localised brain activity does not generate a conscious experience, more widespread brain activity when consciousness is present.
When does the attentional blink peak?
300ms, at 100ms and 600ms it is not that affected
