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Baylis, 2004
Cappelletti, 2006
Farah, 1990
Marshall & Halligan, 1988
Saj, 2014
100
Why do JJ, JL, and WK have different reaction time patterns on the same task?
JJ has right hemispatial neglect, while JL and WK have left hemispatial neglect.
100
What are some examples of findings (regarding numerical processing in neglect patients) that were published before this paper?
- mental representation of the number line was shifted to the right - subitizing is preserved even when unaware of the stimulus - neglected numbers could still be recruited for arithmetic tasks
100
Define the three potential reference frames discussed in this paper.
Viewer-centered, environment-centered, object-centered
100
Researchers presented P.S. with two vertically or horizontally aligned houses in alternate ordering. What did her responses suggest about the frame of reference that was used?
an object/task-centered frame of reference
100
What is the result of deficits in "spatial representation", as a function of left hemispatial neglect, according to Saj et al.?
Deficit in representing events in time, particularly in the past, or attributing future events incorrectly to past events
200
Why were the reaction times in tasks 2 and 3 greater than in task 1?
The subjects had to hold their task instructions in working memory.
200
What is congruency and how is it related to reaction time?
In the context of this paper, two numbers are congruent if they are both odd/even or both greater/less than 5. Reaction time is smaller for the comparison of congruent stimuli.
200
If Megan is lying on her side reading her book, which reference frames are coupled/decoupled?
Environment is decoupled from viewer-centered and object-centered.
200
Step 5 (fire on right side of one house vs normal house) primed P.S. to notice that there was a fire on the left side of one of the houses in step 6. How may this be related to Baylis et al's article?
The left of whatever you're attending to is ignored, so the fire/no fire paradigm in step 5 may have cued P.S. to attend to a fire rather than the house (which step 1 -- they presented her with the cards and asked her what she say, to which she responded seeing a house -- may have cued her attend to)
200
What determines the way people think about mental time lines?
Culturally specific spatial themes and cues e.g. reading an alphabet left to right
300
What was the purpose of task 2? (Why didn't they skip it and go straight into task 3)?
Acted as a control for the addition of shapes to the display.
300
Explain the numerical relation effect.
Patients had faster reaction times when the two presented numbers were closer to each other (1 and 3) than further away (1 and 4).
300
What does Table 2A tell us?
T2A confirms that the subjects have left hemispatial neglect. Since all reference frames are aligned, it tells us nothing about the contribution of these reference frames.
300
P.S. presents left neglect as well as left hemianopia. What allows the researchers to conclude that their observations of her are a consequence of neglect?
the persistence of those observations after P.S. turns her head/visual field and her preference for the non-burning house indicates her visual system is intact
300
What is the task that Saj et al. presented to their participants?
A memory experiment with an encoding phase, recall-test phase, recognition test phase, where participants are given “past” and “future” information about a fictional characters They receive this information during the encoding phase and then in the recall-test phase, they have to pull up stimuli or items that were mentioned in the encoding trial phase. The recognition-test phase is where the participants were shown pictures and asked if they had seen them AND THEN identify it the item was associated with the past or the future.
400
What are the two types of scene-based neglect and what were the authors' predictions for each?
Scene-based -- attention is entirely based on the visual hemifields. No difference between reaction times when objects are placed in the same hemifield (regardless of the degree away from the fovea) Scene-based (gradient) -- gradient of attention across the visual field, so reaction time would also be a gradient!
400
Assume that two numbers, 1 and 4, were presented in the left and right visual fields, respectively. In which of the paper's tasks would the reaction time be fastest? Why?
The number comparison task because both are <5. The number parity judgement task would be slower since 1 and 4 are incongruent (one odd, one even).
400
How would Table 2c be different if the object-centered reference frame DID contribute to the spatial attention system?
The values in the "left object" columns would be smaller than the "right object" columns. The "view/environment" columns would remain the same.
400
Walk the class through the order of card presentations.
1) two cards were shown independently 2) two cards were shown together (vertically aligned), asked if anything was "wrong" 3) same as 2, but instead asked which house she'd like to live in 4) same as 2, but instead asked whether the cards are the same or different 5) two new cards (flames now on the right side of the house) presented, asked if the cards are the same or different, asked which she'd prefer to live in 6) same as step 4
400
In the recognition test phase, patients with left hemispatial neglect performed _______ in recognizing future items compared to patients without neglect.
Equally as well (refer to Figure 3, Saj et al.)
500
In what type of neglect would the authors expect to see statistically significance for data both within a hemifield and between hemifields, but no interaction between the two?
Scene-based (gradient)
500
Why were incongruent trials not analyzed for the numerical relation effect?
"The numerical relation was confounded with the distance separating the left number from the reference number (5)."
500
What are the dorsal and ventral visual pathways and how do they relate to this paper?
The authors suggest that the dissociation between object-centered and viewer/environment-centered frames exist because the module for the former is held in the ventral visual pathway (shape/spatial coordinates), whereas the module for the latter is held in the dorsal visual pathway (location/spatial coordinates outside of a given object).
500
When asked if there was anything wrong with either card, P.S. replied that there wasn't, but when asked which house she'd prefer to live in, P.S. chose the non-burning house. What accounts for the difference in response and how could the researchers re-word the first question to illuminate the difference between the 2 houses?
The former question requires conscious awareness/processing of left space: though she may be unconsciously aware of a difference, P.S. would have to be able to articulate (be consciously aware of the fact) that there's a difference between the 2 houses. It would be better to ask her what house has something wrong with it.
500
Previous studies have shown that patients who have neglect don't just have deficits in temporal dynamics but rather in tone duration such as not being able to identify tones presented in the left ear (Husain, Shapiro, Martin & Kennard 1997). Along with the findings of Saj et al. there is a suggestion that...
There are neural substrates that have a role in representation of spatial and temporal information. One possible brain region implicated in these shared functions is the posterior parietal cortex.