Tms and Perception Flashcards
What is the power as a lesion technique?
The power lies in combining reversible disruption with high levels of temporal and spatial resolution
What is the process of generating TMS?
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
When was the human motor cortex stimulated for the 1st time?i
1985
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
O performance was impaired ②subject could not identify stimulus/letters
Which orientation of NC maximises the depth of penetration?
Tangential
Ammasian s interference with perception → what were the characteristics/inferences
① masking and unmasking visual stimulus: one can performance by interfering with transmission of irrelevant or compering stimuli or impair performance by interfacing
What were the results of shifting the site of MC on perception by a subject of 3 dark letters? (Midline→ left /right)
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
What were the Impacts/results of rostrally moving MC on 3 dark letters displayed vertically?
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
Discuss the results inferred by amassian while facilitating for perception. ( hint: masking unmasking the letters)
→ 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 )
What is extinction?
Attentional deficit phenomenon (visual) but not as extreme as Attentional neglect
Participants only perceive ipsilaterally stimulus when they are presented bilaterally
What were the results of the paxcual-leone studies?
→ applied rTMS over occipital, parietal,temporal cortices
→ errors enhanced at parietal area but for bilateral presentation and results in contralateral hemifield being not visible
What were the results of the paxcual-leone studies?
→ applied rTMS over occipital, parietal,temporal cortices
→ errors enhanced at parietal area but for bilateral presentation and results in contralateral hemifield being not visible
Why was rtms more useful than single pulse tms?
→cognitive processesare processed through parallel pathwayand with sufficient re-entry mechanism are required to block them.
What did ashbridge and colleagues interpret from applying TMS to parietal cortex during visual search task?
→ TMS applied to P.C. When performing a search serially slowed down response but it ( time taken ) depends on presence or absence of target
What were the types of trials presented in ashbridge research?
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
What. Is the function of visual cortex activity in blindness? Cohen et al.
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
Who was the first scientific psychologist to text cognition processes?
Donders:
Mental chronometery and reaction time experiment
What was the subtraction method and assumptions?
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.
What are the different categories of journals?
① General ②field ③ sub-field ④ specialized
What are the models of Journal distribution?
→ 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
How do we operationalize visual awareness?
Methods: ① calibration→
V1and V5 area : identify the scalp location foe induction of moving and stationary phosphenes and the required minimum field strength
V5 to V1 experiment to understand importance of backprojections?1
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
What were the 4 different responses to experiment.?
1: moving ph in same location
2: phosphor but not very clearly moving
3: phosphor in same place but net moving
4: No ph
What were the 2 results of the experiment?
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 .
