Tms and Perception

Question 1

What is the power as a lesion technique?

Answer 1

The power lies in combining reversible disruption with high levels of temporal and spatial resolution

Question 2

What is the process of generating TMS?

Answer 2

①electric current generated in a capicitator and
Discharged into figures coil→ magnetic pulse of 2.5 Tesla ② The pulse keeps changingand the consequent magnetic field generates an electric field inducing neural activity

Question 3

When was the human motor cortex stimulated for the 1st time?i

Answer 3

1985

Question 4

What are the impacts of applizing single pulse TMS over the occipital cortex during The following time periodsduring called letter identification task?
① 60-140ms ② 80-100 Ms

Answer 4

O performance was impaired ②subject could not identify stimulus/letters

Question 5

Which orientation of NC maximises the depth of penetration?

Answer 5

Tangential

Question 6

Ammasian s interference with perception → what were the characteristics/inferences

Answer 6

① masking and unmasking visual stimulus: one can performance by interfering with transmission of irrelevant or compering stimuli or impair performance by interfacing

Question 7

What were the results of shifting the site of MC on perception by a subject of 3 dark letters? (Midline→ left /right)

Answer 7

① left letter- most visibly/correctly reported when ‘ TMS on left hemisphere however the least visible if TMs on right H. ②middle letter- highest when MC moved to extremes and other locations consistent across③ right letter-correct response when MC on ipsilateral visual field and errors (most) made on contralateral hemisphere

Question 8

What were the Impacts/results of rostrally moving MC on 3 dark letters displayed vertically?

Answer 8

Top letter- most visible and identified correctly ( 3 cm)
middle letter: correctly responded to after 2 cm bottom letter: not visible at all till 3cm

Question 9

Discuss the results inferred by amassian while facilitating for perception. ( hint: masking unmasking the letters)

Answer 9

→ disinhibiting to improve performance
→ letter identification arraysfollowed by 100 Ms high contrast visual mask and TMS s (single pulse)applied at various intervals after mask
→ role of TMS to was to prevent visibility of mask in order to see the letters
→ results:when TMS applied to visual cortex resulted in identification of target letters ( MAX at 100 Ms to 120 Ms )

Question 10

What is extinction?

Answer 10

Attentional deficit phenomenon (visual) but not as extreme as Attentional neglect
Participants only perceive ipsilaterally stimulus when they are presented bilaterally

Question 11

What were the results of the paxcual-leone studies?

Answer 11

→ applied rTMS over occipital, parietal,temporal cortices
→ errors enhanced at parietal area but for bilateral presentation and results in contralateral hemifield being not visible

Question 12

What were the results of the paxcual-leone studies?

Answer 12

→ applied rTMS over occipital, parietal,temporal cortices
→ errors enhanced at parietal area but for bilateral presentation and results in contralateral hemifield being not visible

Question 13

Why was rtms more useful than single pulse tms?

Answer 13

→cognitive processesare processed through parallel pathwayand with sufficient re-entry mechanism are required to block them.

Question 14

What did ashbridge and colleagues interpret from applying TMS to parietal cortex during visual search task?

Answer 14

→ TMS applied to P.C. When performing a search serially slowed down response but it ( time taken ) depends on presence or absence of target

Question 15

What were the types of trials presented in ashbridge research?

Answer 15

Pop-out: stimulus was distinctlyvisible and did not impact RT even if no. Of distractors increased. Doesn’t require attention. But for conjunction -trials no. Of distractors do impact rt.
TMS applied to pop out vs i
- doesn’t impact pop out
- impacts conjunction trial

Question 16

What. Is the function of visual cortex activity in blindness? Cohen et al.

Answer 16

Adaptive functioning reorganization
Primary visual cortex is repurposed in response to tactile stimulation
Cohen et al. Interrupted tactileinfo-processing by stimulating the occipital cortex of blind
Disrupted stimuliprocessing when applied to mid-occipital cortex

Question 17

Who was the first scientific psychologist to text cognition processes?

Answer 17

Donders:
Mental chronometery and reaction time experiment

Question 18

What was the subtraction method and assumptions?

Answer 18

Subtraction methods: choice RT - Simple RT ,
① assumption of serial stages- processing stages occur after other and not parallel ‘
② assumption of pure insertion: adding an additional stage would not change length of other stages.

Question 19

What are the different categories of journals?

Answer 19

① General ②field ③ sub-field ④ specialized

Question 20

What are the models of Journal distribution?

Answer 20

→ traditional:free for researchersbut test for libraries to get access.
O pros → incentive for rigorous peer-reviewed and high quality to boost sales
O cons → expensive and limited access to scientific output
→ open access: cost for reccarchers to subunit articlesand face access
O pros-open access
O cons- incentive to accept submissions to attract more submissions thenferenacase collected fees

Question 21

How do we operationalize visual awareness?

Answer 21

Methods: ① calibration→
V1and V5 area : identify the scalp location foe induction of moving and stationary phosphenes and the required minimum field strength

Question 22

V5 to V1 experiment to understand importance of backprojections?1

Answer 22

V5: we apply TMS at 100% of threshold( single pulse)→ induces moving phosphor
Vi: conditioning stimulus at 80% of threshold ( goal: net induce phosphenes)
V5 - v1 asynchrony-time difference btw v5&vi stimulus

Question 23

What were the 4 different responses to experiment.?

Answer 23

1: moving ph in same location
2: phosphor but not very clearly moving
3: phosphor in same place but net moving
4: No ph

Question 24

What were the 2 results of the experiment?

Answer 24

① when TMSrapplied to V1 after V5 it disrupts phosphate perception 5 ms to 45 ms
② when TMS applied to V5 [superatureshold and sub] it does not disrupt perception
Therefore there is imps of v5 to v1 back projection for motion awareness .

Question 25

Why does TMS to vi disrupt motion awareness?

Answer 25

① feedback to vi necessary forvisual awareness
② interference in V5 due forward projections [ vi to V5]
→ exp 2
Results→ forward projections have no role to play as TMS over v5 (subthereshold did not cause disruption to motion )
③ back masking of ph by stationary ph s ruled out

Question 26

Why doesn’t TMS to V5 disrupt visual awareness?

Question 27

What are the possibles with exp?

Answer 27

① 18/26 participants excluded didn’t see pho.
② localization error - nearby areas
③ backward masking by stationary ph. Of moving ph.

Question 28

What is the spatial resolution of us?

Answer 28

Millimeters to centimetres ( 0.001 to 0.01)

Question 29

Walsh & Corey exp → figure with black and blue lines, what does it represent?

Answer 29

Black Lin: interference with perception (TMS applied 100 Ms after )
Blue line: facilitation of perception

Question 30

What info does mt/v5 provide and what lobe of the brain is it.

Answer 30

Info - about motion → where and how stream(dorsal)
Location - temporal/parietal lobe→ temporal/parietal occipital lobes meet

Question 31

What is ponders subtraction method? What are its assumptions?

Answer 31

Subtraction method is used to detectthe time taken to make a decision → choice RT - simple RT
Assumptions: ① serial stages:there is no overlap btw 2 stages and if there is it is a violation.
② pure insertion:adding a stage does not impact the length or durations of other stages ( faster or slower) and if it does its a violation

Question 32

Violation of serial stages impact?

Answer 32

Underestimating the exp.

Question 33

What will be the impact of violation of pure insertion?

Answer 33

If a stage occurs faster → underestimationof previous stages
Stage occurs slower → overestimation of prior stages