bayesian brain

Question 1

describe placebo effects in the context of the bayesian brain

Answer 1

prior expectations change one’s response to stimuli

control:
– no drug
– no expectation of pain
– pain feels normal
experimental:
– "powerful drug" (placebo)
– expect pain to be low
– same level of pain feels less intense

Question 2

what is mis-match negativity and how does is use predictive coding?

Answer 2

the mismatch negativity is an increased brain response to violations of a rule, established by a sequence of sensory stimuli

high-order areas generate predictions and send to low-order areas

if prediction is same as stimuli, there is little activity
i.e. when something is predicted only small neural response needed to encode it

if different, prediction errors are generated and ascend through hierarchy
i.e. large neuronal response needed to code unpredicted stimulus

Question 3

does repetition suppression impact mismatch negativity?

Answer 3

yes

subjects in repetition block shows normal response:
– low response in repetition trial
– increased response in alternating trial

subjects in alternating block showed no statistically significant difference between trials, as the repetition was not expected and ∴ no prediction effect