Psych 302 Exam 1
What are the TWO problems that Longer Blocks have? (2) For the first problem, at more than how many seconds do you start to get smaller or larger signals of WHAT? (2) (MAIN) Does this mean that ther is a Sagging of BOLD signal? For the second problem, for very low or high frequencies, there's a lot of WHAT? (2) (MAIN) Beyond how many seconds, the background noise has to be lower or higher than the actual experiment? Why don't you want TWO frequencies sounding alike? For HIGH BOLD use what type of frequency? For LOW BOLD use what type of frequency?
1. At more than 20 seconds, you're starting to get SMALLER signals of BOLD. (MAIN) - Sagging of BOLD signal. 2. For very LOW frequencies, there's a lot of NOISE. (MAIN) - Beyond 60 seconds, the background noise has to be LOWER than actual experiment. - That's why you don't want 2 frequencies sounding alike because you might confuse the actual SIGNAL with the NOISE. - For HIGH BOLD use LOW frequency. - For LOW BOLD use HIGH frequency.
What are the TWO popular fMRI designs? Do one or both of these designs check BOLD impulse response?
1. Block Design - A type of research study in which participants are divided into relatively homogeneous subsets (blocks) from which they are assigned to the experimental or treatment conditions. 2. Event-Related Potenial (ERP) - A measure of electrical activity from a subpopulation of neurons in RESPONSE TO A PARTICULAR STIMULI that requires averaging many EEG recordings. BOTH of these check BOLD impulse response.
What are the FOUR goals of scientific research? (4)
1. Describe 2. Explain 3. Predict 4. Change Behavior
What are the THREE keys to conducting and fMRI study? (3)
1. Design a behavioral task that isolates the psychological process(es) of interest. 2. Modify the behavioral task so that it's suitable for an fMRI study. 3. Analyze the behavioral and fMRI data.
What are FOUR ethical considerations to keep in mind?
1. Informed Consent 2. Debriefing 3. Privacy/Confidentiality 4. Fraud
Slice Timing: When are slices collected in each TR? (3) Are slices collected at the SAME time?
1. Interleaved (1,3,5,7.....2,4,6,8) - All odds or All evens. 2. Ascending (1,2,3,4.......) - From the bottom to the top. 3. Descending (24,23,22,21.......) - From the top to the bottom. NO slice collected at the same time.
What does conducting a fMRI study involve? (3) What is the First Step? What is the Second Step? It takes snapshots of brain every how many seconds? Each PING in the scanner means what? It's a pic of one or both sides of the brain? How thick are the images? What are the units called? You measure what in each of these voxels? Do you analyze the data from each voxel? What is the THIRD step? What do they ask subjects to do while inside the fMRI? What does TR stand for?
1. Put someone in the scanner. 2. Record the BOLD Signal. - Take snapshots of brain every 2 seconds. - Each PING in scanner means that they took a snapshot. - It's a pic of ONE SIDE of the brain that is 2-3 mm thick. - Talk about them as VOXELS (3-D thick sheets). - Measuring BOLD signal in each one of these voxels. - Analyze the data from each "voxel" (3-D pixel) 3. Perform Cognitive Task - They ask subjects to do task while inside fMRI. - TR = Repetition Time
Slice Timing is only needed if what TWO things?
1. Temporal dynamics of evoked BOLD responses are important. - (e.g., event-related designs, but not blocked designs) 2. TR is small enough to permit temporal interpolation. - (TR <3 seconds )
Inferring Cognitive Functions in Vegatative State: The brain activity told patients to imagine what TWO things? (2) In between trials there was a WHAT type of period? Are these patients conscious even though they can't say it verbally? This experiment tries to do what with imagination?
A brain activity in which they told patients to Imagine TENNIS and Imagine NAVIGATION. In between trials there was a REST period. They are conscious even though they can't say it verbally. Trying to MANIPULATE imagination.
A t-test is significant when the difference between two sample WHAT is small or large enough that it is unlikely to have WHAT?
A t-test is significant when the difference between two sample MEANS (U1 and U2) is LARGE enough that it is unlikely to have OCCURRED BY CHANCE.
Study Design: What is a Within-Subjects Design?
A type of experimental design in which all participants are exposed to every treatment or condition. Subjects get all the treatments (exposed to everything)
What is a Confound variable? What is an example?
A variable that influences both the dependent variable and independent variable, causing a spurious association. An "extra" variable that you didn't account for. They can ruin an experiment and give you useless results. They can suggest there is correlation when in fact there isn't. EXAMPLE: Clever Hans: Horse that could do math, but found out later he knew math because of cues (such as persons reactions). This contributes as a confound variable because it made people think that the horse could actually do math.
Does the ACC underlie selection for action or just trigger it via conflict monitoring? (Continued): The ACC shows more activity for what when it's higher than lower? So what is controlling the ACC? What is NOT being controlled by the ACC?
ACC shows more activity when CONFLICT is high than lower. This means the ACC is doing CONFLICT MONITORING and not SELECTION FOR ACTION.
Selection for Action (Attention Adaptation): After an incongruent trial and with a long time between the distracter and the target, subjects might be able to do what? If they shift all of their attention to the target, there won't be exactly WHAT to identify WHAT? Due to this, there should be no WHAT after WHAT type of trials?
After an incongruent trial and with a long time between the distracter and the target, subjects might be able to shift all of their attention to the time at which the target appears. If they shift all of their attention to the target, there won't be any left to identify the distractor. Thus, there should be no CONGRUENCY EFFECT after INCONGRUENT trials.
What is the Blood Oxygen Level Dependent (BOLD) Signal? What are the FOUR steps of how it works? (4) What happens in the First Step? (1) What happens in the Second Step? (1) What happens in the Third Step? (4) What happens in the Fourth Step? (2)
An INDIRECT measure of neural activity. Four Steps: 1. Increased Neural Activity (Thinking!) 2. Increased Blood Flow - Blood flows to area of brain of what you are thinking about. 3. Baseline/Active - Baseline: Oxygen and Blood flow are normal. - Active: Cognitive processes are occuring. So, surplus of freshly oxygenated blood. The oxy/deoxyhemoglobin ratio increases. 4. Increased BOLD Signal - Oxygenated to Deoxygenated can be seen with fMRI. - Increased in Blood Flow LOOK AT SLIDE 8.
What are True Experiments?
An actual experiment with different groups and IVs and DVS and controlled variables. A type of experimental design and is used to establish cause and effect relationships.
Study Design: What is a Between-Subjects Design?
An experiment that has two or more groups of subjects each being tested by a different testing factor simultaneously. Subjects get different treatments. One group gets treatment while other group doesn't.
What did the FIRST "Brain Imaging Experiment" look like? What was the name of the physiologist that created it?
Angelo Mosso would place patients on see saw. If subjects brain interacted with something then blood would rush to the brain and see saw would go down from the head portion.
Smoothing: What is smoothing? How is this done?
Basically, spreads out the activation of a voxel to it's neighbors. - This helps to get everyone's activity. How? Replace the intensity value of a voxel with a weighted average of its original value plus the value of neighbouring voxels. CHECK SLIDE 22.
The Block Design gets WHAT because of the amount of WHAT? (3) You add up the trials to see how BOLD response gets WHAT? (2) Does the ERP design have a small or large BOLD response? This is because it has less or more trials? Overall, BOLD responses can be WHAT? (2)
Block Design: Gets TALLER and LONGER because of the amount of TRIALS it has. You add up the trials to see how BOLD response gets TALLER and LONGER. ERP Design: Has a SMALLER BOLD response because it has LESS trials. OVERALL BOLD response can be SMALL or BIG.
Neuronal activity from TWO event types without jitter: Why would we get a bad estimate of BOLD signal?
CHECK SLIDE 28 We would get a bad estimate of BOLD signal because there's not a lot of trials.
BOLD signal without jitter: When purple is presented it's what? When yellow is presented it's what? The White is the difference between how many trial types?
CHECK SLIDE 28 When purple is presented it's HIGHER. When yellow is presented it's LOWER. Your difference between TWO trial types! (Information)
Rapid Unjittered Design Example: What's right (1) and wrong (2) about the BOLD responses above?
CHECK SLIDE 29 Right: 1. The difference between TWO trial types can be seen. (cI & iI). Wrong: 1. How much is active on BOLD signal. 2. Not measuring accurately the low level baseline.
Slice Timing: Which time course below (green or blue) comes from the slice that was collected later in the TR? When later in the TR, does it move left or right? You shift the slices to make it look as if all the data is WHAT? You align slices to the most RIGHT for what type of slice pic? You align slices to the most LEFT for what type of slice pic?
CHECK SLIDE 7 Green curve is later in the TR. When later in the TR it moves to the LEFT. You shift to make it look as if all the data is TEMPORARY ALIGNED. Align to the most RIGHT for the EARLIEST SLICE PIC. Align to the most LEFT for the LATEST SLICE PIC.
What were Schmidt and Weissman trying to find out? What was their question?
Can a CSE be observed without feature repetition, contingency learning, or mental rotation confounds?
Class Experiment
Class Experiment
What is Functional Connectivity?
Communication between brain regions. If activity in two regions is correlated across time, then these regions may be communicating. (MAIN) CHECK SLIDE 35.
Are active regions ASSOCIATED with performing a task or ESSENTIAL for performing a task? How can lesion studies help to answer this question?
Concept of Reading: There are multiple ways to read so there are areas ASSOCIATED with reading, but moving your mouth is ESSENTIAL for reading. How can lesion studies help to answer this question? If an individual has a certain area lesioned, and they can't do a task then that brain area specifies exactly what it does as soon as participant can't do it.
What is a Correlative Study?
Correlate two things together, but there might be a third variable affecting it. (NOTES) Determines whether or not two variables are correlated. This means to study whether an increase or decrease in one variable corresponds to an increase or decrease in the other variable.
Cued Stroop Task: What were the Cues? (2) How long were the delays? What were the TWO targets and give example? (2) What is the ACC for? What is the DLPFC for? Are these results slow event related?
Cued Stroop Task: Example of a Double Dissociation Cue: "Word" or "Color" 15 s delay Target: Congruent (Word and color green) or Conflict (word is blue & color is red) Results: ACC = Conflict DLPFC = Attention Slow Event Related
Does the ACC underlie selection for action or just trigger it via conflict monitoring? (2) What is the trial type for Conflict Monitoring? Is there lower or higher conflict? This happens because? What is the trial type for Selection for Action? Is there lower or higher selection for action? This happens because?
EXAMPLE: cI & iI Conflict Monitoring: From Congruent to Incongruent (cI) there is HIGHER conflict because they didn't expect to get tricked. Selection for Action: From Incongruent to Incongruent (iI) there is HIGHER selection for action because if previous trial was Incongruent to Incongruent (iI) then individual starts becoming more Selection for Action. So if the after trial is Incongruent to Congruent (iC) then individual starts to be more focused on second trial which means selection for action.
Why do BOLD signals have Undershoots?
Each of the BLUE lines is a BOLD Response. Since there are so many BOLD Responses, those responses start to drag the BOLD signal down. Also known as the undershoot.
Experimental Design - Behavioral Studies
Experimental Design - Behavioral Studies
What is Preprocessing?
Gets rid of variability in the BOLD signal that is not due to the task.
What was the GOAL? What was the METHOD?
Goal: Distinguish between these two accounts with the prime-probe word task. Method: Increase the time separating the prime (distracter) from the target (probe) from 33 ms to 800 ms.
What is Cognitive Subtraction? What is Assumption of Pure Insertion? If we add an insertion and compare them then we will only see what? Is it only sometimes or always inserted in experimental condition?
How to Infer the Function of a Brain Region Cognitive Subtraction: - Compare two conditions that are similar in some factors, but are different in some (ONE) factor. Assumption of Pure Insertion: - Add a cognitive process to experimental condition WITHOUT changing the processes that were already there. - If we add an insertion, and compare them then we will only see difference of process that we inserted. - ALWAYS inserted in experimental condition.
Faces vs Houses Experiment: What TWO things would subjects see? How long did they see it for? Was there a one second break in between each trial? Why is this experiment considered a BLOCK design?
In this experiment, Every SECOND they would see a Famous House/Face or a Not Famous House/Face and press a button. In between each second, there was a second for rest. This is a BLOCK Design because it notices what brain areas acitvate for FACES and HOUSES.
What is Response Inhibition? Is this one of the control processes that can drive the CSE?
Inhibit the response engendered by the distracter. You inhibit the response to not get it wrong. You are consciously thinking that those distractors tripped you up, and you tell yourself to not get distracted so you INHIBIT the response. YES IT IS!
Slice Timing: What is Slice Timing? Every time you hear a beep what does that mean? Every 100 miliseconds it collects how many slices from the 20 whole slices in TR? Every 2 seconds it collects how many slices of the brain?
It TEMPORARILY aligns data. Each of those slices are collected by each beep. Every 100 miliseconds collects ONE slice from the 20 whole slices in TR. Every 2 seconds it collects 20 slices of the brain.
Rapid Jittered ER Design: What is Rapid Jitter? Since there are more trials, this allows us to what? Is this the same in unjittered designs? Is the BOLD signal response messy? If not, does this help us see the low-level baseline (BOLD)?
Jittered Design: Varies time between trials. Neuronal activity from TWO event types with jitter: Has more trials which allows us to estimate low-level baseline (BOLD signal). - Not for unjittered design. BOLD signal with jitter: BOLD response signal is not messy which helps us see the low-level baseline (BOLD).
Lecture 1: Introduction
Lecture 1: Introduction
Lecture 2: Summary of Conflict Adaptation
Lecture 2: Summary of Conflict Adaptation
Lecture 3: Basic Statistics
Lecture 3: Basic Statistics
Lecture 5: What is fMRI?
Lecture 5: What is fMRI?
Lecture 6: How To Design fMRI Studies
Lecture 6: How To Design fMRI Studies
Lecture 7: How To Preprocess fMRI Data
Lecture 7: How To Preprocess fMRI Data
Longer Neural Signals leads to what type of BOLD response? (2) Is this considered a Superposition? How does this happen? (3) Explain using an example!
Longer Neural Signal leads to TALLER and LONGER BOLD response. (Superposition). WHATS GOIN ON? 1. A long neural signal is like a series of shorter neural signals. 2. When it occurs, each shorter signal gives rise to its own response. 3. These individual responses then summate to yield a large response. EXAMPLE: For TWO trials, the BOLD signal is just TALLER. For TWENTY trials, the BOLD signal is TALLER and LONGER. The BOLD signals are adding up per trial.
MRI (or Structural MRI) is used to study what? Functional MRI (or fMRI) is used to study what?
MRI (or 'structural MRI'): - Used to study brain ANATOMY. Functional MRI (fMRI): - Used to study brain FUNCTION.
Main Effects and Interactions
Main Effects and Interactions
Interpreting BOLD Signal: What does the BOLD signal measure? This metabolic activity occurs for both what? (2) Is BOLD signal that though? BOLD signal won't tell you between what? (2)
Measures METABOLIC activity. This occurs for both EXCITATION and INHIBITION, but don't think BOLD signal is that. BOLD won't tell you between EXCITATION and INHIBITION.
What is Diffusion Tensor Imaging (DTI)?
Measures structural changes in brain's white matter tracts by tracking the diffusion of water.
What is One-tailed? They're about what percent? Is this only on one side or each side? One-tail are conducted by saying what? (2)
One-tailed: Where the region of rejection is on ONLY ON ONE SIDE of the sampling distribution. For example, suppose the null hypothesis states that the mean is less than or equal to 10. The alternative hypothesis would be that the mean is greater than 10. 5% ONLY on one side. One tail are conducted by saying whether we reject or dont reject.
What is a P-Value?
P-value: Probability that the sample mean came from the "null" distribution above.
What are the Pros (3) and Cons (1) of Event-Related Designs (ERP)?
PROS: 1. Get a nice BOLD signal response to individual events. 2. We can code each trial different and eliminate some trials. - Can't happen in Block Design. 3. Strategy Difference - Each trial can't be thought of, so actually have to be though out. CONS: 1. Produce smaller signals which means that they are harder to predict.
What are the Pros (2) and Cons (3) of Block Designs?
PROS: 1. Signals are really big which make it easier to detect. 2. When a cognitive process takes long to complete. - Ex. Visual Imagery: Navigate home/living room. CONS: 1. Error trials are hard to get rid of. 2. Can't get at individual trials where funky things happen. - Can't fix them. 3. Inability to randomize tasks will lead to subjects finding ways to cheat the system.
T-Tests: What is Paired (one-sample) t-test? What's an example? What is an Unpaired (two-sample) t-test? What's an example?
Paired (one-sample) t-test: The two sample means come from the SAME subjects. Example: Does drinking coffee boost test performance? Compare the test scores of 100 students after they drink coffee vs. water Unpaired (two-sample) t-test : The two sample means come from DIFFERENT subjects. Example: Does drinking coffee boost test performance? Compare the test scores of 100 students after they drink coffee to the test scores of 100 students after they drink water.
What are Mental Rotation Confounds? How did Schmidt and Weissman find out about this confound?
People were mentally rotating the arrows to make it look simpler for them. They found out this confound because Incongruency took LESS time then congruency (took longer).
Slow Event-Related Designs: How long should ONE stimuli or ONE trial be present for in a SLOW ERP Design? What do you do to compare responses? (2) Why is the average BOLD response larger for stimuli in the left visual field (A) than for stimuli in the right visual field (B)? Increase is taller in what hemisphere? Does this give a larger or smaller BOLD signal?
Present ONE stimuli or ONE trial for about 16 to 20 seconds. You get the AVG response of trial A (Left Visual Field) and the AVG response of trial B (Right Visual Field) and then compare responses. EXAMPLE: The figure below plots BOLD responses in the right occipital cortex to individual visual stimuli presented once every 16 seconds in the left visual field (A) or the right visual field (B). (CONTEXT) Why is the average BOLD response larger for stimuli in the left visual field (A) than for stimuli in the right visual field (B)? Right vision goes to the Left Hemisphere and the Left vision goes to the Right Hemisphere. Increase is taller in the RIGHT HEMISPHERE which gives a LARGER BOLD signal.
How does Structural MRI work? Protons take different amount of WHAT to reallign on WHAT?
Protons are moved to reallign when in MRI. Protons take different amount of TIME to reallign on GRAY and WHITE matter.
Realignment & Coregistration: During a head motion, you align each brain volume to a WHAT using 3 translation and 3 rotations? What is Target Volume?
Realignment Estimates and Corrects for Motion: Aligns each brain volume to a TARGET VOLUME using 3 translations and 3 rotations. Target Volume: The functional volume that is closest in time to the anatomical image. Choose a reference volume, and make sure the rest go to that reference one.
Dogs and fMRI: Are reward activations the same or different between dogs and humans?
Reward activation is the SAME in dogs and humans.
Slice Timing: SPM assumes each scan is what? Does it want to line things up?
SPM assumes each scan is 'INTANTANEOUS' It wants to line things up. CHECK SLIDE 6.
Schmidt and Weissman Experiment 2
Schmidt and Weissman Experiment 2
What is Selection for Action (Attention Adaptation)? What are the THREE triggers? Is this one of the control processes that can drive the CSE?
Shift attention toward the relevant target. Putting more attention on the target stimulus after an incongruent trial. Three Triggers: 1. Perceptual Expectation (Expect Shape) 2. Conflict Monitoring (Monitor more closely) 3. Negative Affect (Get Frustrated) YES IT IS!
How Long Should Blocks Be? This timing is done to not give much time for the WHAT to do WHAT? (2) Once you get at a lower or higher timing, you let the WHAT go to WHAT? (2)
Should be 2 SECONDS to not give much time for the BOLD signal to go DOWN. - Ex. Rest, 2 Secs, Rest, 2 Secs, etc. Once you get at HIGHER timing, you let the BOLD design go to BASELINE (ALL THE WAY DOWN).
What does Stats tell us?
Statistics tell us how likely a particular sample mean is to come from the distribution associated with the null hypothesis.
What are Contingency Learning Biases? Is this done consciously or not? Why was the Ullsperger task an issue? (2) Did subjects figure out an indicator of a congruent trial? Did this cause them to break the experimental design? What were they focusing on that they weren't supposed to be focusing on? Is this an influence on the CSE?
Subejcts were figuring out the pattern! It is NOT conscious. The way you think about what's going to happen next. Why was it an Issue? 1. Only one way CONGRUENT. 2. Multiple ways of INCONGRUENT. Easy for subjects to understand. Subjects were figuring out an indicator of a congruent trial. They broke down the whole experimental design. They weren't focusin on the numbers, but were instead finding ways to cheat the system. YES IT IS!
What is the Prime-Probe Word Task? What does the Prime mean in the task? What does the Target mean in the task? Did this avoid repetition?
TASK: Indicate the direction specified by the large target word (left, right, up, down), not the preceding distracters (left, right, up, down). Prime: Repeated words in a column (distracter) Target: One Large word in the middle. This avoided repetition! - Ex. Up/Down or Down/Up or Up/U
What is the Prime-Probe Word Task? What does the Prime mean in the task? What does the Target mean in the task? Did this avoid repetition?
TASK: Indicate the direction specified by the large target word (left, right, up, down), not the preceding distracters (left, right, up, down). Prime: Repeated words in a column (distracter) Target: One Large word in the middle. This avoided repetition! - Ex. Up/Down or Down/Up or Up/Up or Down/Down
Two Block Design: The resulting signal reveals mainly differences in WHAT? Since the signal stays HIGH, is there a poor or great estimate of baseline? This block design MAXIMIZES our ability to detect WHAT at the EXPENSE of detecting WHAT? Is it easy or hard to estimate the baseline of BOLD signal?
TWO Block Design: The resulting signal reveals mainly differences in ACTIVITY BETWEEN THE BLOCK TYPES (signal stays high so POOR estimate of baseline). This design maximizes our ability to detect DIFFERENCES IN ACTIVITY at the expense of detecting ABSOLUTE ACTIVITY. It's hard to estimate baseline of BOLD signal. CHECK SLIDE 17. (RED ARROWS).
What is the Congruency Sequence Effect thought to reflect?
The CSE is thought to reflect ATTENTIONAL MECHANISMS THAT COPE WITH DISTRACTION.
Canonical BOLD Response: What is the Initial Undershoot? What is the Brief Signal? What is the Peak? What is the Undershoot? Describe what they look like.
The Canonical BOLD Response: - LOOK AT SLIDE 9 Initial Undershoot: - This is where an image is presented and the blood that is already there is being deoxygenated. Brief Signal: - Basically BOLD Signal, its the ration of oxygenated to deoxygenated hemogobling. Peak: - Where most of the blood rushes too which is where the activity is taking place in. Undershoot: - Since there are so many BOLD Responses, those responses start to drag the BOLD signal down. Also known as the undershoot.
The Fusiform Face Area (FFA) specializes in what? The Parahippocampal Place Area (PPA) specializes in what?
The FFA specializes in Faces (Activates when it sees faces). The PPA specializes in Places (Houses in this case) (Activates when it sees places like houses).
What is the Congruency Sequence Effect (CSE)? What is CSE also called? Why is the Congruency Effect smaller after Incongruent trials than after congruent trials? Are Congruent Trials slower or faster? Are Incongruent Trials slower or faster?
The congruency effect is smaller after incongruent trials than after congruent trials. Also called CONFLICT ADAPTATION. The CSE is smaller after incongruent trials than after congruent trials because people get the previous task wrong and their reaction times slows down to make sure they don't get tricked again. Congruent Trials are FASTER. Incongruent Trials are SLOWER. CHECK SLIDE 21.
What is Main Effect?
The effect of an independent variable on a dependent variable averaged across the levels of any other independent variables.
What are Simple Effects? Simple effects only take into consideration what? Are you looking at one side or both sides in simple effects? Only calculate simple effects if there is a what type of effect?
The effect of one independent variable within one level of a second independent variable. Simple effects only take into considertion ONE IV. In simple effects you are just looking at one side. (look at notebook). Only calculate simple effects if there is a SIGNIFICANT effect.
What is the LOGIC of the experiment? Would subjects be able to use thier memory of whether the previous trial was congruent or incongruent to PREDICT whether the upcoming trial would be congruent or incongruent? If subjects make such predictions, we should observe WHAT even though there is no overall WHAT? Due to this, we should be able to distinguish between what TWO accounts for CSE?
The overall congruency effect should vanish when the distracter appears much earlier in time than the target. (MAIN). But subjects may still use their memory of whether the previous trial was congruent or incongruent to predict whether the next trial will be congruent or incongruent. If subjects make such predictions, we should observe a CSE even though there is no overall CONGRUENCY EFFECT! Moreover, we should be able to distinguish between the SELECTION FOR ACTION (ATTENTION ADAPTATION) and RESPONSE INHIBITION accounts of the CSE.
What were the Results? What is the Overall Conclusion? Can a CSE be observed or not to be independent of feature repetition and contingency learning confounds? This suggests that control process influences the CSE, but does not reveal what? (2)
There was a very STRONG CSE!!!! CONCLUSION: A CSE CAN be observed independent of feature repetition and contingency learning confounds This suggests that a control process influences the CSE, but does not reveal which one: - Selection for action (attention adaptation) - Response inhibition
Realignment & Coregistration: What do Realignment & Coregistration do? What is the effect of head motion on our data?
They SPATIALLY align data. What is the effect of head motion on our data? When head motion occurs, the brain moves which makes it harder to identify a BOLD signal.
Clinical Application & fMRI: What type of patients did they test? What were they asked to think of? Did they unconsciously or consciously do what they were asked?
They were VEGETATIVE patients. Were asked to think of playing Tennis and or Walking. They CONSCIOUSLY respond of what was asked of them.
What are Feature Repetitions? The results are not due to WHAT but instead of WHAT? (2) Would arrows repeat for both congruent and incongruent trials? Who came up with this learning and memory process? Is this an influence on the CSE?
This is when an individual notices REPETITIONS on arrows and it helps the individual go FASTER. The results are not due to CONFLICT but instead of REPETITIONS. For both Congruent and Incongruent trials they would repeat (arrows). MAYR came up with this learning and memory process. This is another influence on the CSE.
What is Two-tailed? What percent? Is this only on one side or each side? They want to reject the null or the alternative?
Two-tailed: Where the region of rejection is on BOTH SIDES of the sampling distribution. For example, suppose the null hypothesis states that the mean is equal to 10. The alternative hypothesis would be that the mean is less than 10 or greater than 10. 2.5% on EACH side. Only want to reject the null hypothesis.
Design Types: What is an Unjittered Design? Give an example. What is the Jittered Design? Give an example. Are both of these designs in rapid unjittered and ERP?
Unjittered Design: Doesn't vary time between trials. - Happens every 2 seconds. Jittered Design: Varies time between trials. - Happens first for 3 seconds, then 5 seconds for next, etc. BOTH in rapid unjittered and ERP.
What is a Descriptive Study?
Used to describe characteristics of a population or phenomenon being studied. It does not answer questions about how/when/why the characteristics occurred. (ONLINE) Ask any question to see the answer (NOTES) Ex. How many peas have you eaten?
Normalisation: What is Normalisation? Why do we Normalise?
Warp each subject's brain to a template (average) brain. - Merge everyone's brain together. (One Space) CHECK SLIDE 19 Why do we Normalise? If we AVG the brain of all the subjects, it helps us to locate a region that all the subjects have interactions in.
Movies and Brain Activity: How exactly do we watch movies?
We take SNAPSHOTS of movies. They are mini pictures and we speed up the process.
Two Block Design: What if we want to detect absolute activity too?: We could include WHAT between our two blocks of interest? (2) The resulting signal reveals what TWO things? This design is MORE efficient at detecting WHAT but LESS efficient at detecting WHAT? (2)
What if we want to detect absolute activity too? We could include a LOW-LEVEL BASELINE CONDITION (E.G. FIXATION) between our two block types of interest. The resulting signal reveals: 1. ACTIVITY for each block type (green= BOLD SIGNAL). 2. DIFFERENCE IN ACTIVITY between the two block types (red = HOUSES TO FACES). LOOK AT SLIDE 18. This design is MORE EFFICIENT at detecting ABSOLUTE ACTIVATION , but LESS EFFICIENT at DETECTING DIFFERENCES.
The Linearity Assumption: What do you do in a Linear Assumption? You want to keep trials spaced by how many seconds to see linearity?
When you subtract trials you get about same shape. Want to keep trials space by 2 seconds to see linearity, nothing less. CHECK SLIDE 26
Response Inhibition: With a long time between the distracter and target, subjects might be able to what? This happens after which type of trials? If they do do that, there should be WHAT after WHAT type of trials?
With a long time between the distracter and target, subjects might have time to inhibit the response signaled by the distracter after INCONGRUENT trials. If they do, there should be a NEGATIVE (I.E. REVERSE) CONGRUENCY EFFECT after INCONGRUENT trials.
Can we go faster? If yes, do we have to test assumptions regarding linearity of BOLD signal first? Why would we want to go faster, though?
Yes, but we have to test assumptions regarding linearity of BOLD signal first. Why would we want to go faster, though? May not perform task if going to slowly then if it was going at normal speed.
When will you know if there is an interaction?
You'll know if there's an interaction if they aren't parallel.
What does Functional MRI (fMRI) do? What does Structural MRI do?What does Diffusion Tensor Imaging (DTI) do?
fMRI: - Where COGNITIVE PROCESSES are located in brain. Structural MRI: - The type of TISSUE that is seen in a part of a brain. DTI: - Uses water to measure structural changes in white matter tracts.
