Difference between revisions of "CNP SCAP"

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===Basic Task Description===
 
===Basic Task Description===
  
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This task was developed in the Cannon Lab, originally by David Glahn. This behavioral version is the most basic, traditional version of the task. It differs from the [[SCAP | LA5C SCAP version]], in a few ways described below. This task has been run on most of the local Cannon Lab UCLA samples including Aftercare (first episode), CAPPS (prodromal), chronic and NF1 subjects. It has also been run in Finnish and Swedish samples.
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        The goal of this task is to probe behavior across different levels (loads) of a spatial working memory capacity task. There is evidence that spatial working memory is impaired in schizophrenia, and the deficit may be a core feature of the disease. From our previous schizophrenia twin studies we have evidence that the spatial working memory deficit (as assessed by a version of this task) may be heritable (Glahn et al, 2003). There is further evidence that performance on this task may differentiate between bipolar patients with and without a history of psychosis (Glahn, 2006).  
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The Cannon lab has a great deal of experience with this task, and it has been administered in a very wide variety of populations at a number of sites. We have administered it to adolescents with schizophrenia, prodromal subjects, aging Finnish twins with and without schizophrenia, chronic schizophrenia patients, bipolar patients, patients with neurofibromatosis-1, and healthy controls. The version that we have administered most frequently is the one used in the LA2K, a block design task with 4 memory loads (1,3,5 and 7 locations).  
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===Task Procedure===
 
===Task Procedure===
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This task manipulates working memory load. The loads were selected to be of parallel difficulty, in terms of performance, to the loads in the [[VCAP]].
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This task manipulates working memory load. The loads were selected to be of parallel difficulty, in terms of performance, to the loads in the [[CNP_VCAP]].
  
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First, subjects undergo a training period
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'''Sample Text'''<br/>
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During the SDRT, subjects were shown a target array of 1, 3, or 5 yellow circles positioned pseudorandomly around a central fixation. After a fixed delay, subjects were shown a single green circle and were required to indicate whether that circle was in the same position as one of the target circles. A relatively long stimulus presentation was used to allow subjects to fully encode the target array, minimizing a potential encoding on the basis of set size interaction. Likewise, decision or selection requirements were kept constant across set sizes to reduce possible effects of set size on response processes. Trial events included a 2-sec target-array presentation, a 3-sec delay period, and a 3-sec fixed response interval. A central fixation was visible throughout each of the 36 trials (12 per memory set size).<br/>
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Glahn, 2003<br/>
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===Task Structure Detail===
 
Loads: 1, 3, 5 or 7 dots
 
Loads: 1, 3, 5 or 7 dots
  
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Each trial lasts 9 seconds. TR=3s<br/>
 
Each trial lasts 9 seconds. TR=3s<br/>
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'''Text'''<br/>
 
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During the SDRT, subjects were shown a target array of 1, 3, or 5 yellow circles positioned pseudorandomly around a central fixation. After a fixed delay, subjects were shown a single green circle and were required to indicate whether that circle was in the same position as one of the target circles. A relatively long stimulus presentation was used to allow subjects to fully encode the target array, minimizing a potential encoding on the basis of set size interaction. Likewise, decision or selection requirements were kept constant across set sizes to reduce possible effects of set size on response processes. Trial events included a 2-sec target-array presentation, a 3-sec delay period, and a 3-sec fixed response interval. A central fixation was visible throughout each of the 36 trials (12 per memory set size).<br/>
 
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Glahn, 2003<br/>
 
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===Task Structure Detail===
 
  
 
===Task Schematic===
 
===Task Schematic===
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[http://www.ncbi.nlm.nih.gov/pubmed/12679242 Glahn et al, 2003, Biological Psychiatry]<br/>
 
[http://www.ncbi.nlm.nih.gov/pubmed/12679242 Glahn et al, 2003, Biological Psychiatry]<br/>
 
[http://www.ncbi.nlm.nih.gov/pubmed/12482077 Glahn et al, 2002, Neuroimage]<br/>
 
[http://www.ncbi.nlm.nih.gov/pubmed/12482077 Glahn et al, 2002, Neuroimage]<br/>
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[http://www.ncbi.nlm.nih.gov/pubmed/16542181 Glahn et al, 2006, Bipolar Disorders]<br/>

Revision as of 16:08, 21 June 2011

go back to HTAC

Basic Task Description

       The goal of this task is to probe behavior across different levels (loads) of a spatial working memory capacity task. There is evidence that spatial working memory is impaired in schizophrenia, and the deficit may be a core feature of the disease. From our previous schizophrenia twin studies we have evidence that the spatial working memory deficit (as assessed by a version of this task) may be heritable (Glahn et al, 2003). There is further evidence that performance on this task may differentiate between bipolar patients with and without a history of psychosis (Glahn, 2006).

The Cannon lab has a great deal of experience with this task, and it has been administered in a very wide variety of populations at a number of sites. We have administered it to adolescents with schizophrenia, prodromal subjects, aging Finnish twins with and without schizophrenia, chronic schizophrenia patients, bipolar patients, patients with neurofibromatosis-1, and healthy controls. The version that we have administered most frequently is the one used in the LA2K, a block design task with 4 memory loads (1,3,5 and 7 locations).


Task Procedure

This task manipulates working memory load. The loads were selected to be of parallel difficulty, in terms of performance, to the loads in the CNP_VCAP.

First, subjects undergo a training period

Sample Text
During the SDRT, subjects were shown a target array of 1, 3, or 5 yellow circles positioned pseudorandomly around a central fixation. After a fixed delay, subjects were shown a single green circle and were required to indicate whether that circle was in the same position as one of the target circles. A relatively long stimulus presentation was used to allow subjects to fully encode the target array, minimizing a potential encoding on the basis of set size interaction. Likewise, decision or selection requirements were kept constant across set sizes to reduce possible effects of set size on response processes. Trial events included a 2-sec target-array presentation, a 3-sec delay period, and a 3-sec fixed response interval. A central fixation was visible throughout each of the 36 trials (12 per memory set size).
Glahn, 2003

Task Structure Detail

Loads: 1, 3, 5 or 7 dots

There are 12 trials per load, the trials are blocked in sets of 2, and analyzed in those blocks.

Trial layout:
1. Fixation for 1sec
2. Target array for 2 sec
3. Delay period for 3 sec
4. Probe array (single dot) for 3 seconds

Each trial lasts 9 seconds. TR=3s

Task Schematic

Task Parameters Table

Stimuli

Dependent Variables

Cleaning Rules

Code/Algorithms

Data Distributions

References

Cannon et al, 2005, Archives of General Psychiatry
Glahn et al, 2003, Biological Psychiatry
Glahn et al, 2002, Neuroimage
Glahn et al, 2006, Bipolar Disorders

Retrieved from "http://lcni-3.uoregon.edu/phenowiki/index.php?title=CNP_SCAP&oldid=6701"