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K-Limbic Developers Guide
Stage Type Reference
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5.2.12 Serial Choice – Present Stimulus Stage
Components:
• Driver Controls
• Display Message
• Stage Exit Triggers
• Stage Reports
Function
A “Serial Choice – Present Stimulus” stage is specifically designed to perform the “Present Stimulus”
function in the five-choice serial reaction-time task.
The stage sets the state of the operant chamber, (normally just the house light), then presents the
stimulus, the stimulus is a “flash” of a cue light in one of the niches. The stimulus parameters are
controlled by the auto control, which in turn is determined by settings in the five choice parameters of
the subject database. The stage pauses for a response in one of the niches, (correct or incorrect), or
for the stage timeout to occur. The stage timeout is called the “Limited Hold” period.
The “Limited Hold“ period is specified using the Limited Hold setting of the five choice parameters of the
subject database.
Stimulus presentation is a special function of the “serial choice – present stimulus” stage. Presentation
of the stimulus is automatic. The developer is not concerned with defining the stimulus when
developing the protocol. The subject database and auto control deal with the stimulus presentation.
The “Serial Choice – Present Stimulus” stage always resets the stage timer on entry therefore it can be
re-entered many times in the same trial and will always last for the full Limited Hold period, however the
standard five choice paradigm assumes that one stimulus occurs per trial.
The “Serial Choice – Present Stimulus” stage automatically assigns the niche in which the stimulus
occurred as the “target” resource, all remaining “nosepoke” sensors are automatically assigned as
“dummy” resources. A response in the correct niche triggers the “Exit On Target” endpoint, a response
in any incorrect niches triggers the “Exit On Dummy” endpoint.