Three-Choice Serial Reaction Time

A Centre Object is presented in the centre of the screen, and the subject must touch it, and keep touching for a specified duration. (Optionally, it is rewarded for this.)

Then a different object is presented in one of three locations for a certain duration (typically brief) [RNC: unclear whether SIdse wanted a choice from three objects, or just three locations; the latter is most akin to the rat 5CSRTT so I've gone with that]. The subject must respond (within a timeout), and is rewarded for doing so. It's punished for missing or getting it wrong.

Sidse also wants to be able to choose whether the targets are randomly distributed among the three locations (33% - 33% - 33%) in the test phase, or are distributed with a different pre-specified distribution. I'm not sure why, but it's in there. Think twice before using it, though!

The requested level system was a bit complex. In any case, no matter what the level, the duration of the phase 1 object didn't vary. The two variables were (1) delay preceding the target; (2) target duration. It's important in the 5CSRTT that the delay preceding the target can vary randomly; our rat version allows random variation of this delay but requires you to specify stimulus duration in advance. So I think we should add one level of flexibility (whilst not implementing Sidse's request exactly) and allow the user to specify a list of delays and a list of target durations, and then have the program choose from each.

Note that as the delay can be zero, the location of the centre object mustn't be the same as one of the targets (otherwise the pig would be touching the centre target as soon as it was displayed). So the centre target is placed below centre (with the intention that the target locations will be visible while the pig touches the centre marker).

•	Maximum number of trials. When the subject has performed this number of trials, the task ends. (You may specify 0 for no limit, though you must specify a limit on the number of trials, the time, or both.)

•	Maximum time. When this time elapses, the task is terminated as soon as the current trial has finished. (You may specify 0 for no limit, though you must specify a limit on the number of trials, the time, or both.)

•	Time between trials. Specify a minimum and a maximum intertrial time (they may be the same). The actual time is chosen with a rectangular probability distribution within these values.

•	Phase 1 - Stimulus. Choose the centring stimulus (the one that the subject has to keep touching for a while before the targets appear). Click Set to choose the stimulus.

•	Phase 1 - Maximum time to wait for a response. If the subject fails to respond within this time, the subject fails the trial.

•	Phase 1 - Time for which subject must touch stimulus. Choose the length of time for which you want your subject to keep its nose on the centring stimulus.

•	Phase 1 - Reward correct performance. Optionally, you can reward your subject for passing Phase 1 - but I [RNC] don't recommend it, as your subject wouldn't then be facing the right way to watch Phase 2!

•	Phase 2 - Punish premature responding. If the subject responds in one of the three possible target locations before the target is presented, this is termed a premature response. You can punish these (in which case the trial will be terminated).

•	Phase 2 - Target stimulus. Choose the target stimulus by clicking Set.

•	Phase 2 - "Absent stimulus" marker. During the delay, while the target is being presented, and afterwards, any locations that aren't showing the target show this marker stimulus. Choose the stimulus by clicking Set. Typically, this stimulus would be an empty box.

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Phase 2 - Equiprobable locations? If ticked, p(target on the left) = p(target in the middle) = p(target on the right) = 1/3. If you wish, you can force the location probabilities to something else by removing this tick and filling in the p(left) and p(right) boxes. Obviously, p(middle) = 1 - p(left) - p(right) in these circumstances.

•	Phase 2 - Maximum time to wait for a response. This time is measured from the start of the target stimulus. If this time limit expires and the subject hasn't responded, it fails the trial.

•	Possible delays before target stimulus. Use the Add and Remove buttons to create a list of possible delay values. Every trial, a delay is chosen at random from this list.

•	Possible target stimulus durations. Use the Add and Remove buttons to create a list of possible stimulus duration values. Every trial, a stimulus duration is chosen at random from this list.