What can fMRI tell us about cognition? Flashcards
why do neurons differ in length and size?
connect to different brain regions > further apart require longer neurons
receive messages from other cells =
dendrites
electrical activity can be detected on the scalp using an _____
EEG
what is the function of fMRI?
how the brain is responding and where activity is generated in specific brain regions
why do we need to have an anatomical scan for each ppt?
everyone has a different brain structure
Oxygen is delivered to neurons in ________ in _______ RBCs
haemoglobin, capillary
why do neurons need oxygen?
because they lose energy when they fire electrical signals > this needs to be replenished
why would a resting neuron show reduced blood flow?
doesn’t need as much O2 as not firing
what does fMRI record?
blood flow towards activated areas of the brain
Hb is ________ when oxygenated and _______ when deoxygenated
diamagnetic, paramagnetic
does diamagnetic Hb or paramagnetic Hb have a stronger magnetic field?
diamagnetic > as is oxygenated!
what is the fMRI response to oxygen called?
the BOLD response
what does BOLD stand for?
Blood Oxygen Level Response
there is an initial ____ in haemodynamic blood flow followed by an _____ that overcompensates for the amount of oxygen used
dip, increase
when does the increase in oxygen to Hb start happening?
approx 4 seconds (quite slow)
what is the con associated with fMRI?
the delay between when we respond to a stimulus and when we can measure a response (low temporal resolution)
why is there a delay in measuring a response?
because we have to wait for the blood supply to be redirected to that area
what shows how magnetic the Hb is?
the MR signal
when does the MR signal peak in the BOLD response?
between 4 and 8s
too much O2 in the area once it is oxygenated (peak) then dissipates out and brings it back to normal levels =
primary response
what happens after the primary response?
a negative overshoot where area becomes slightly deoxygenated
what are the 3 planes that the brain can be viewed?
coronal (front), saggiato (side) and axial (down)
why might we combine EEG and fMRI?
they have complementary pros and cons which allows us to deepen our knowledge
which method has low temporal resolution but high spatial resolution?
fMRI
which method has low spatial resolution but high temporal resolution?
EEG
give an example of where EEG and fMRI are combined
early visual processing
how we process visual stimuli and the immediate response =
early visual processing
what stimulus do we often use for EEG studies testing visual processing?
changing checkerboard
a robust response to a stimulus that shows a consistent change that happens repeatedly and shows a pattern =
ERP
how is 1 ERP trace in response to a stimulus produced?
average the traces across multiple trials
what spike in the ERP is produced when we process visual info?
P100 (called this because its a positive spike and occurs at 100ms)
what parietal side of the brain is P07 on and what side of visual field does it pick up stimulus?
left side of brain > picks up stimulus on right
what parietal side of the brain is P08 on and what side of visual field does it pick up stimulus?
right side of brain > picks up stimulus on left
what ERP spike is present for both P08 and P07 electrodes?
p100
what is good for observing the Visual Evoked Potential?
EEGs > picks up electrodes P07,P08 and ERP of p100
fMRI scans tell us that visual processing occurs where?
primary visual cortex
what is the specific ERP for face processing (both upright and inverted faces) but not other objects?
N170
fMRI results show different patterns of responding for faces and non-faces. how do we see what areas are for faces?
subtract patterns responding to faces away from patterns for non faces
are there slightly different regions for responding to inverted vs. upright faces?
yes
electrical activity to upright and inverted faces but not scrambled faces or chairs. What ERP and what electrodes?
N170 and P07/P08
what on EEGs show where the electrical activity is likely to have emerged but not a clear location?
heat maps
what can combined EEG-fMRI show us about early visual processing and face processing?
what regions were activated at 100ms, what regions were involved, when was N170 activated
how are humans good at face processing?
detect faces and where people are looking, can infer intentions/beliefs/emotions looking at other peoples eyes
what is the differences in eye tracking data between asian and western cultures?
different patterns of eye movements when looking at the face (asian > focus on nose, western > focus on eyes, mouth and nose)
what were the behavioural results in Adams et al (2010) reading in the mind in the eyes ToM task?
Japanese were more likely to guess emotions from eyes from own culture and less likely when american stimuli was used (same own cultural bias for american ppts)
what were the fMRI results in Adams et al (2010) reading in the mind in the eyes ToM task?
same brain regions responsible for processing faces, ppts showed stronger pattern of activation for stimuli from their own culture vs. other culture, activated in the bilateral pSTS (area for ToM reasoning and eye gaze perception)
what brain region is activated for processing faces?
superior temporal sulcus
a very small specific area located behind your ear =
superior temporal sulcus
what were the results from Kana et al (2016) study involving explicit and implicit emotion videos for autistic and neurotypical ppts?
stronger levels of activation in the medial PFC and pSTS for NT ppts in implicit condition compared to autistic ppts, didn’t differ in control and implicit condition for autistic, autistic could process explicit emotions but not implicit (unconsciously), same regions for both though
autistic people recruit task specific brain regions for processing emotions when explicitly (aware) to do some but not implicitly. what is the implication?
perhaps more explicit instructions are needed for autistic individuals when emotion processing is required would be helpful
reduced activity in the identified brain regions may indicate reduced likelihood of reflective thoughts regarding spontaneous emotion processing. what is the implication?
maybe this is why autistic people often have difficulty in recognising subtle emotions
what is a limitation of fMRI used in experiments?
low ecological validity > artificial scanning so can’t be used in real life
what brain regions are critical to different aspects of social cognition?
medial prefrontal cortex, amygdala, posterior superior temporal sulcus
who developed second person neuroscience?
Leon Schilbach
non interactive stimulus, passive perception, argued to be social observation rather than social interaction, ppt knows it isn’t real =
3rd person neuroscience (thought not to be a good measure of social interaction)
interactive stimulus, responds to ppt in fMRI scan, live social partner/avatar, ppt thinks its real =
2nd person neuroscience
it is thought that we must have different activations in our brain for when we are actually involved in social ______ compared to social _______
interactions, observations
the cognitive neuroscience of real world interactions, dual brain studies where 2 people are in separate fMRI scanners and interacting with each other =
hyperscanning
how does hyper scanning give us a greater idea of how our brains function in a social interaction?
brain of sender sending messages and receiving messages > real interaction > allows you to see the reciprocal pattern of a social interaction, can see how peoples brains respond and what neural networks are involved that may be different from social observation
what were the results from Anders et al (2011) couples hyper scanning study?
male became in tune with female partner and brain showed similar patterns of activation, shared network effect!!
what is the shared network effect?
activity in 1 persons brain can influence the activity in another persons brain, info can be successfully transferred > creates a shared space of affect
what does the paradigm from hyper scanning/2nd person neuroscience provide?
a tool that will open a new perspective in social neuroscience
what could 2nd person neuroscience tell us about cognition?
which brain regions involved, how the brain activity of one persons brain affects another, ask new Qs about mechanisms of social behaviour, ask Qs why some people have social interaction difficulties
as cognitive neuroscientists we can use a combo of how brain mechanisms affect real world outcomes and vice versa = what approach?
brain as predictor approach
what is the framework of the brain as predictor approach?
provides another path to understanding our psychological processes and how our brain responds in the real world
how brain as predictor approach work?
generate a hypothesis of which brain regions are involved > collect data measuring neural activation and behaviour outcomes > test whether activity in brain regions predicts behaviour outcomes
