TMS & Perception (3)

Question 1

What are the different types of journal articles?

Answer 1

-general: all fields, very influential and most impactful topics (ex. nature & science)
-field
-sub-field
-specialized

Question 2

What is the impact factor?

Answer 2

the impact of influence of the journal calculated by the average of how often an article is cited in a year

Question 3

What are the different journal distribution models?

Answer 3

-Traditional: free to submit articles, cost to receive (read)
-Open-access: cost to submit articles, free to receive (read)

Question 4

What are the pros and cons of traditional journal distribution models?

Answer 4

-Pros: rigorous peer-review and high quality to increase sale
-Cons: expensive, limited access to scientific output (particularly to those outside of the academy or less wealthy countries)

Question 5

What are the pros and cons of open-access journal distribution models?

Answer 5

-Pros: unlimited free access to everyone!
-Cons: incentive to accept submission (some called predatory journals and will publish anything)

Question 6

What are some alternative journal distribution models?

Answer 6

-funding agencies (ex. NSERC in Canada) require open access after 12 months
-institutionally funded open-access journals

Question 7

What is the organization of an original research article?

Answer 7

IMRaD hourglass organization
1) Introduction
2) Methods
3) Results
4) Discussion/ Conclusion

Question 8

What journal was Pascual-Leone and Walsh (2001) published in?

Answer 8

Science

Question 9

What is Pascual-Leone and Walsh (2001) research question?

Answer 9

what role do backprojections from the motion area to primary visual cortex play in the visual awareness of motion?

Question 10

What is the organization of the visual system?

Answer 10

• serial, parallel and recurrent processing
• info flows forwards and backwards
• dorsal: “where/how” stream (where things are in the world relative to us. How we need to move to interact w/ them)
  -ventral: “what” stream (what things are. Specific to faces)

Question 11

What is serial processing

Answer 11

allows for only one object at a time to be processed

Question 12

What is parallel processing?

Answer 12

various objects are processed simultaneously

Question 13

What is recurrent processing?

Answer 13

information flows forwards and backwards

Question 14

What areas were the researchers focused on?

Answer 14

• V1: primary visual cortex
• MT/V5: motion area
• info travels up to MT/V5 but also backprojects from MT/V5 to V1

Question 15

What is visual awareness?

Answer 15

being aware or conscious of what is around you

Question 16

How do we operationalize visual awareness?

Answer 16

If one is able to self-report it (report their experience or lack of experience of visual awareness of motion)

Question 17

What is a backprojection?

Answer 17

information sent from a higher level area back down to a lower level area (ex. V5 to V1)

Question 18

How was V5 calibrated?

Answer 18

-identified scalp location for induction of ‘moving’ phosphenes (flash of light that is experienced when TMS is applied to the visual cortex)
-identified minimum field strength for consistent induction of moving phosphenes

Question 19

How was V1 calibrated?

Answer 19

-identified scalp location for induction of stationary phosphenes in same perceived location as moving phosphenes
-identified minimum field strength for consistent induction of stationary phosphenes

Question 20

What was important when calibrating V1 and V5?

Answer 20

-the moving phosphenes evoked in V5 and stationary phosphenes evoked in V1 were occurring in the same location in the visual field
-allows you to be confident that you’re targeting the same location in the topographic maps in V1 and V5 (parts of the maps that represent the same location in the visual field)

Question 21

What TMS stimulus did the researchers us?

Answer 21

-single pulse test stimulus to V5 at 100% threshold to induce moving phosphene
-single pulse conditioning stimulus to V1 at 80% threshold to not induce stationary phosphene

Question 22

What was the time between the pulses called?

Answer 22

“V5-V1” asynchrony” or “Conditioning to test asynchrony”

Question 23

What would the participants report?

Answer 23

1) moving phosphene same as with single V5 TMS
2) moving phosphene, but not as clear as single V5 TMS
3) phosphene in same location as V5 TMS but not moving
4) no phosphene

Question 24

What is the independent variable and dependent variable in this study?

Answer 24

-IV: V5-V1 asynchrony
-DV: phosphene report

Question 25

What are the results of the V5 to V1 experiment?

Answer 25

-when reading figure: 0 means pulses were at the same time, positive is how long after V1 is to V5
-pulse of V1 at 25ms after V5, interferes with awareness of moving phosphene

Question 26

What do the results of the V5 to V1 experiment suggest?

Answer 26

-feedback to V1 is necessary for visual awareness of motion
-interference in V5 due to forward projections from V1 to V5
-backward masking of motion phosphenes by later stationary phosphenes

Question 27

What are the methods of the V5 to V5 experiment?

Answer 27

-single-pulse test stimulus at 100% to V5
-single pulse conditioning stimulus at 80% to V5
-time between called “conditioning to test asynchrony”

Question 28

What results were seen in the V5 to V5 experiment?

Answer 28

a secondary pulse to V5 does not interfere with the perception of motion in any way

Question 29

What do the results from the V5 to V5 experiment indicate?

Answer 29

-rules out the interference in V5 due to forward projections from V1 to V5 in the previous experiment
-it is unclear why TMS to V5 does not disrupt visual awareness of motion

Question 30

What is the researchers conclusion?

Answer 30

• Our results highlight the importance of the fast feedback projections from V5 to V1 in visual awareness of motion and document the chronometry of the phenomenon

Question 31

Why is TMS the only possible method to conduct this experiment?

Answer 31

• a lesion to V1 would just cause vision loss
• EEG and fMRI not able to block
• TMS is able to block a specific area for a shortened time

Question 32

What are some potential issues with the study?

Answer 32

• backward masking of motion phosphenes by later stationary phosphenes? But no reports of multiple phosphenes
• 18 of 26 participants excluded for failure to perceive reliable V1 or V5 phosphenes
• localization: V1 or nearby areas actually being affected

Question 33

What are some possible follow up questions?

Answer 33

• Does V1 play a similar role for other visual phenomena? (colors, shapes, faces)
• Does V1 play a similar role for visually presented motion stimuli?