Difference between revisions of "CNP SMNM"

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(Task Procedure)
(Task Procedure)
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'''Sample Text'''<br/>
 
'''Sample Text'''<br/>
Each trial began with a 1500ms encoding period during which participants were presented with 3 yellow dots and were instructed to do their best to remember the exact locations of the 3 yellow dots and note their relationship to a horizontal line across the center of the screen.  Following the encoding phase, a trial-type cue was presented for 1 sec.  This cue informed the participant of what cognitive challenge is required for the delay phase.  Participants either saw the word “Hold” or “Flip”.  For trials with the “Hold”, or M, cue, participants were asked to simply remember the locations of the three yellow dots.  During trials with the “Flip”, or MnM, cue, participants were asked to mentally flip the three dots into their mirror locations across the dotted line.  There were equal numbers of trials for both conditions in which all three, two, one, or none of the three dots were above the horizontal line.  As an additional cue a vertical bar remained across the fixation cross during the delay period, with flat tips if trial was a hold trial and arrow tips if the trial is a flip trial. After a 6 sec delay, a set of green dots appeared for 1500ms during which participants were to decide whether the set of green dots matched the exact locations (in the M condition) or the exact inverted locations (in the MnM condition) of the yellow dots."
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"Each trial began with a 1500ms encoding period during which participants were presented with 3 yellow dots and were instructed to do their best to remember the exact locations of the 3 yellow dots and note their relationship to a horizontal line across the center of the screen.  Following the encoding phase, a trial-type cue was presented for 1 sec.  This cue informed the participant of what cognitive challenge is required for the delay phase.  Participants either saw the word “Hold” or “Flip”.  For trials with the “Hold”, or M, cue, participants were asked to simply remember the locations of the three yellow dots.  During trials with the “Flip”, or MnM, cue, participants were asked to mentally flip the three dots into their mirror locations across the dotted line.  There were equal numbers of trials for both conditions in which all three, two, one, or none of the three dots were above the horizontal line.  As an additional cue a vertical bar remained across the fixation cross during the delay period, with flat tips if trial was a hold trial and arrow tips if the trial is a flip trial. After a 6 sec delay, a set of green dots appeared for 1500ms during which participants were to decide whether the set of green dots matched the exact locations (in the M condition) or the exact inverted locations (in the MnM condition) of the yellow dots."
  
 
===Task Structure Detail===
 
===Task Structure Detail===

Revision as of 17:22, 27 June 2011

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Basic Task Description

This is a working memory task with conditions challenging both maintenance and manipulation of items being held in working memory. It was developed by Junghoon Kim, David Glahn, and Tyrone Cannon in the Clinical Neuroscience Lab at UCLA. This task has been administered in a number of healthy and patient samples at UCLA as well as in Finland and Sweden.

This version of the task differs slightly from earlier versions, in which the maintenance and manipulation trials were separated into 2 blocks. This design potentially allowed subjects to form strategies that might specifically affect the manipulation trials (for instance, knowing the trial was a manipulation trial, subjects might flip the stimuli while they were still on the screen rather than during the delay period). In this version, trials are intermixed, and the cue that indicates which type of trial is occurring happens only after the target stimuli are off the screen.

Task Procedure

Basic Task Info

Trial layout:
1. Target
2. Cue to flip or hold
3. delay
4. Probe
5. ITI

First, subjects undergo an instruction and training period (2 trials each of maintenance and manipulation, and then 4 with trial types intermixed), then the task begins and the subject performs 40 trials (20 trials per condition, randomly selected).

Sample Text
"Each trial began with a 1500ms encoding period during which participants were presented with 3 yellow dots and were instructed to do their best to remember the exact locations of the 3 yellow dots and note their relationship to a horizontal line across the center of the screen. Following the encoding phase, a trial-type cue was presented for 1 sec. This cue informed the participant of what cognitive challenge is required for the delay phase. Participants either saw the word “Hold” or “Flip”. For trials with the “Hold”, or M, cue, participants were asked to simply remember the locations of the three yellow dots. During trials with the “Flip”, or MnM, cue, participants were asked to mentally flip the three dots into their mirror locations across the dotted line. There were equal numbers of trials for both conditions in which all three, two, one, or none of the three dots were above the horizontal line. As an additional cue a vertical bar remained across the fixation cross during the delay period, with flat tips if trial was a hold trial and arrow tips if the trial is a flip trial. After a 6 sec delay, a set of green dots appeared for 1500ms during which participants were to decide whether the set of green dots matched the exact locations (in the M condition) or the exact inverted locations (in the MnM condition) of the yellow dots."

Task Structure Detail

Task Schematic

Smnm bigschematic.jpg

Task Parameters Table

Stimuli

Dependent Variables

Cleaning Rules

1. If any of the calculated variables are missing, that subject should be listed for exclusion. 2. If Trial Count is not =40, then that subject should be listed for exclusion. 3. If overall performance (average percent correct) is below 50% (chance, in this task), that subject should be listed for exclusion. 4. If average RT is greater than 6000ms that subject should be listed for exclusion.

It is worth considering dropping people with performance >50% on either maintenance or manipulation (rather than just on the average).

If you want to know if your group looks approximately like it should, in every sample run so far, accuracy is lower in manipulation than maintenance, and reaction time is greater in manipulation than maintenance. This should be the first group level analysis, to quickly verify everything is correct. It would be highly unexpected to have a deviation from this pattern, even though the position along the y axis (overall accuracy or RT) may vary, especially in patient groups.

Code/Algorithms

All of the code for this is the same as that seen in the calculations above.

These are the rules for cleaning the data, as written in Stata:

//ALL SUBJECTS
//get breakdown of numbers in each group:
bysort status: summarize ptid
bysort la5ccontrol: summarize ptid
bysort gender: summarize ptid

//see how many complete cases there are.
count if smnm_main_mn !=.

//exclusions

generate float smnm_percent_corr=(smnm_manip_mn + smnm_main_mn)/2
count if smnm_percent_corr<=.5
count if smnm_trialcount != 40 & smnm_main_tt !=.
count if (smnm_main_mnrt >6000 | smnm_manip_mnrt <6000) & smnm_main_tt !=.

//create variable summing exclusion criteria
generate float useable_smnm= 1 if smnm_trialcount==40 & smnm_percent_corr>.5 & smnm_main_mnrt< 6000 & smnm_manip_mnrt<6000
count if useable_smnm==1

//SUBJECTS WITH USEABLE DATA
bysort status: summarize ptid if useable_smnm==1
bysort la5ccontrol: summarize ptid if useable_smnm==1
bysort gender: summarize ptid if useable_smnm==1
summarize age smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if useable_smnm==1
bysort status: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if useable_smnm==1
bysort la5ccontrol: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if useable_smnm==1
bysort gender: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if useable_smnm==1

//COMPLETERS WITH USEABLE DATA
generate float comp_useable_smnm= 1 if smnm_trialcount==40 & smnm_percent_corr>.5 & smnm_main_mnrt< 6000 & smnm_manip_mnrt<6000 &status==2
count if comp_useable_smnm==1
bysort status: summarize ptid if comp_useable_smnm==1
bysort la5ccontrol: summarize ptid if comp_useable_smnm==1
bysort gender: summarize ptid if comp_useable_smnm==1
summarize age smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_smnm==1
bysort status: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_smnm==1
bysort la5ccontrol: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_smnm==1
bysort gender: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_smnm==1


//OUTLIERS
sktest smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt

grubbs smnm_manip_mn if comp_useable_smnm==1, gen (grubb_smnm_manip_mn)
grubbs smnm_main_mn if comp_useable_smnm==1, gen(grubb_smnm_main_mn)
grubbs smnm_manip_mnrt if comp_useable_smnm==1, gen (grubb_smnm_manip_mnrt)
grubbs smnm_main_mnrt if comp_useable_smnm==1, gen(grubb_smnm_main_mnrt)
grubbs smnm_percent_corr if comp_useable_smnm==1, gen(grubb_smnm_percorr)

generate float comp_useable_nooutlier_smnm=1 if comp_useable_smnm==1 & grubb_smnm_manip_mn !=1 & grubb_smnm_main_mn !=1 & grubb_smnm_manip_mnrt
!=1 & grubb_smnm_main_mnrt !=1 & grubb_smnm_percorr !=1
count if comp_useable_nooutlier_smnm==1
bysort status: summarize ptid if comp_useable_nooutlier_smnm==1
bysort la5ccontrol: summarize ptid if comp_useable_nooutlier_smnm==1
bysort gender: summarize ptid if comp_useable_nooutlier_smnm==1
summarize age smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_nooutlier_smnm==1
bysort status: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_nooutlier_smnm==1
bysort la5ccontrol: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_nooutlier_smnm==1
bysort gender: summarize smnm_percent_corr smnm_main_mn smnm_manip_mn smnm_main_mnrt smnm_manip_mnrt if comp_useable_nooutlier_smnm==1

histogram smnm_percent_corr if comp_useable_smnm==1, frequency bfcolor(gs11) blcolor(black) normal normopts( clcolor(black) ) xtitle(SMNM Overall Percent Correct)
histogram smnm_main_mn if comp_useable_smnm==1, frequency bfcolor(gs11) blcolor(black) normal normopts( clcolor(black) ) xtitle(Maintenance Percent Correct)
histogram smnm_manip_mn if comp_useable_smnm==1, frequency bfcolor(gs11) blcolor(black) normal normopts( clcolor(black) ) xtitle(Manipulation Percent Correct)
histogram smnm_main_mnrt if comp_useable_smnm==1, frequency bfcolor(gs11) blcolor(black) normal normopts( clcolor(black) ) xtitle(Maintenance Response Time (Outliers >1650))
histogram smnm_manip_mnrt if comp_useable_smnm==1, frequency bfcolor(gs11) blcolor(black) normal normopts( clcolor(black) ) xtitle(Manipulation Response Time (Outliers >1800))

Data Distributions

Smnm all data tables.jpg

Smnm all useable tables.jpg

Smnm comp useable tables.jpg

Smnm comp useable tables nooutlier.jpg

Smnm percorr.jpg

Smnm main percorr.jpg

Smnm manip percorr.jpg

Smnm maint rt.jpg

Smnm manip rt.jpg

References

Cannon, 2005, Archives of General Psychiatry
Kim, 2004, Schizophrenia Research
Glahn, 2002, Neuroimage