Dept of Neurophysiology -- Sensory Probe Task Type Documentation

The Sensory Probe with Precedence Effect Task Type (Task Type 9)

The sensory probe with precedence effect task type is similar to the sensory probe 2 task type (type 8). As in the sensory probe 2 task type, there is a first stimulus (visual), and a second stimulus which starts before the first stimulus ends. (The second stimulus must end either before the first stimulus ends or at the same time.) The second stimulus consists of an optional visual stimulus and an auditory stimulus. In task type 8, the auditory part of the second stimulus is a single channel sound. In task type 9, the sensory probe with precedence effect, the auditory part of the second stimulus is a two-channel precedence effect stimulus (see the precedence effect task type (type 5)). It consists of a specific sound waveform which is played out first from one speaker (spkasel) and then, after a short delay (spkbdel), from another speaker (spkbsel).

As in task type 8, the parameters defining the second stimulus of task type 9 can be set up differently for the visual and the auditory parts of the stimulus. In particular, one can specify different starting times for the led2 and speakera/speakerb stimuli (led2strt and spk2strt, respectively). Also, different duration times can be specified (led2dur and spk2dur). Note that spk2strt should be greater than or equal to the sum of spk2dur and spkbdel, due to the precedence delay. One can also specify different locations (selections) for the visual and auditory stimuli (led2sel and the combination of spkasel and spkbsel).

As with the regular sensory probe task type, the animal is expected to spot or look in the direction of the first stimulus and continue to look there as long as it stays on (led1dur), even though there is a second stimulus going during this time period. If the animal first looks within the window of the first stimulus before the time period tspotl1 is over, and continues to looks there for the duration of the first stimulus, it will receive a reward. Otherwise, it fails the task. Unlike other tasks in which there is a second stimulus, this task trains the animal to not look at the the second stimulus at all.

All during this process, the COM program is collecting position data from the cat's eye (and, optionally, ear and head) and also neuronal spike data, as a function of time. After the animal either receives the reward or fails to spot a stimulus properly, the program will continue to collect data for the time period spontim (the spontaneous recording time). At the end of this time period, the trial, or task, is marked as finished, and the program then pauses for a prescribed duration known as the inter-sequence delay. (See the parameters isdrew and isdnorew.) After this, a new trial is begun. The trial process is illustrated in Figure 1.

Figure 1. -- Sensory Probe with Precedence Effect Task Type

Explanation of terms for sensory probe with precedence effect tasks:

first stimulus Led1. See the led1sel parameter.
second stimulus Speakera/speakerb, with optional led2. See led2sel parameters to disable led2. In Figure 1, both led2 and speakera/speakerb are used.
DSS dur Duration of auditory stimulus (speakera and speakerb above). It depends on the duration of the stimulus waveform, as stored in the DSS. It can be less than spk2dur, but not greater than it. See also stimtyp parameter.
SY Starting point of trial.
L1 Time that led1 turns on. See led1strt parameter.
W1 Time that animal spots into window of first stimulus.
L2 Time that led2 turns on. See led2strt parameter, which must be negative for sensory probe trials. It is measured from the end of the first stimulus, so that L2 occurs before the first stimulus is over.
S2 Time that speakera turns on. See spk2strt parameter, which must be negative for sensory probe trials. It is measured from the end of the first stimulus, so that s2 occurs before the first stimulus is over.
R Time that animal receives reward.
E End of trial.

In order to execute sensory probe trials in the COM program, the user must set up the following files:

Fixed Parameter File - This file contains the list of parameters that retain the same values for all trials of a given run of the COM program. There are at least 50 parameters in this list, and they must be specified whenever COM is run. Here is an example of such a fixed parameter set.
Sensory Probe Parameter File - This file contains the list of parameters that define a set of sensory probe trials. The user may specify one or more of these files, each containing a different sensory probe parameter set. Here is an example of one such parameter set.
Macro File - This file contains the list of parameter sets to be used for a run of the COM program. It must contain one fixed parameter file, and one or more parameter set files, as described above. Here is an example of one such macro file.

Note that while a given trial is being executed, the user can type one of several available commands. The program will complete the current trial (so as not to disturb the timing of the trial), and will then process the command that has been typed.

Com Program Documentation -- General
Task Types
Glossary of Parameters -- definitions of all parameters used

If you have questions or comments about this documentation, please send email to jane@neurophys.wisc.edu

This page last modified on : December 5, 2000

first stimulus	Led1. See the led1sel parameter.
second stimulus	Speakera/speakerb, with optional led2. See led2sel parameters to disable led2. In Figure 1, both led2 and speakera/speakerb are used.
DSS dur	Duration of auditory stimulus (speakera and speakerb above). It depends on the duration of the stimulus waveform, as stored in the DSS. It can be less than spk2dur, but not greater than it. See also stimtyp parameter.
SY	Starting point of trial.
L1	Time that led1 turns on. See led1strt parameter.
W1	Time that animal spots into window of first stimulus.
L2	Time that led2 turns on. See led2strt parameter, which must be negative for sensory probe trials. It is measured from the end of the first stimulus, so that L2 occurs before the first stimulus is over.
S2	Time that speakera turns on. See spk2strt parameter, which must be negative for sensory probe trials. It is measured from the end of the first stimulus, so that s2 occurs before the first stimulus is over.
R	Time that animal receives reward.
E	End of trial.