Difference between revisions of "CNP Stop Signal"

Revision as of 05:51, 16 May 2011

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Basic Task Description

The Stop-signal task is a widely used measure of response inhibition and is based on a horse-race model of stopping, which assumes that independent go and stop processes race against one another to determine whether a response is executed or inhibited (Logan and Cowan, 1984; Logan, 1994) (though the independence assumption can be relaxed (Boucher et al., 2007). The primary dependent variable of the task, Stop-signal reaction time (SSRT), provides an individualized measure of inhibitory control. In this task, participants are presented with a series of Go stimuli to which they are instructed to respond quickly. This speeded reaction time task establishes a prepotency to respond. On a subset of trials, the Go stimulus is followed, after a variable delay, by a stop-signal, to which participants are instructed to inhibit their response. The onset of a the stop signal is varied and depends on the participant’s performance, such that it is increased after a previous failure to inhibit and decreased after a previous inhibition. This one-up/one-down tracking procedure ensures that participants inhibit on approximately half of all stop trials, and the horse-race model allows for the estimation of stop-signal reaction time (SSRT), an individualized measure of a participant’s inhibitory ability that controls for difficulty level.

Task Procedure

Largest to smallest task unit

Task Structure Detail

This is what we had worked on before, but could use updating. We'd like to capture a schema that can handle each of the tasks in the CNP, so please think general when editing -fws

• Task Structure (please given an overview of the task procedures here [i.e., overall design, block, trial, and within-trial event structure and timing])
  • procedure
    • block:
    • trial:
• Stimulus Characteristics
  • sensory modality (e.g., visual, auditory, somatosensory, gustatory, olfactory):
  • functional modality (e.g., linguistic, spatial, numerical, categorical):
  • presentation modality (e.g., human examiner, paper, computer display, headphones, speaker):
• Response Characteristics
  • response required -
    • effector modality (e.g., vocal, manual, pedal):
    • functional modality (e.g., words, drawing, writing, keypress, movement):
  • response options (e.g., yes/no, go/no-go, forced choice, multiple choice [specify n of options], free response)-
  • response collection (e.g., examiner notes, keyboard, keypad, mouse, voice key, button press)-
• Assessment/Control Characteristics
  • timing-
  • control/baseline-
  • other?

Task Schematic

Task Parameters Table?

Stimuli

Dependent Variables

Cleaning Rules

Code/Algorithms

Data Distributions

References