Adjust KbQueueCheck to respond to mouse presses?

1
Hi,

I had written the below code to record keyboard presses during a shock-conditioning trial. In each trial a picture is displayed left or right of the centre of the screen, and the participant is instructed to respond with a left or right arrow key. In some cases, the participant will experience a mild electric shock half a second after the image appears on the screen).

My problem is that I need to alter this script now so that it responds to mouse clicks instead of keyboard presses. I know that KbWait works for mouseclick, but I have had trouble finding a similar translation for KbQueueCheck. If I were to use KbWait, I would somehow need to run that loop in parallel to the delay+shock loop.

I would be incredibly grateful for any pointers. Thank you in advance!



                                [Image displayed on screen]

                                KbQueueFlush;
                                imagetime=GetSecs;

                                WaitSecs(0.5); %half second delay before shock
                               
                                [Code for shock delivery]      
                                   
                                [pressed, firstPress]=KbQueueCheck; %check if any key was pressed
                                    if pressed %if key was pressed do the following
                                       firstPress(find(firstPress==0))=NaN; %little trick to get rid of 0s
                                       [endtime, Index]=min(firstPress); % gets the RT of the first key-press and its ID
                                       keyname=KbName(Index); %converts KeyID to keyname
                                       rt=endtime-imagetime; %reaction time
                                    else
                                       rt=1000; %reactiontime set to 1000 indicating there was no response
                                       keyname = 'NoKeyPress';
                                    end


2
XX---In PSYCHTOOLBOX@yahoogroups.com, <gi4c6gsgt272rzcscq2t3ke4oh2v25dszboydduy@...> wrote :

Hi,

I had written the below code to record keyboard presses during a shock-conditioning trial. In each trial a picture is displayed left or right of the centre of the screen, and the participant is instructed to respond with a left or right arrow key. In some cases, the participant will experience a mild electric shock half a second after the image appears on the screen).

My problem is that I need to alter this script now so that it responds to mouse clicks instead of keyboard presses. I know that KbWait works for mouseclick, but I have had trouble finding a similar translation for KbQueueCheck. If I were to use KbWait, I would somehow need to run that loop in parallel to the delay+shock loop.

mouseIdx = GetMouseIndex();
Pass mouseIdx as the deviceIndex parameter to all the KbQueueXXX functions, just as you'd do with KbWait etc. Obviously if you have more than one mouse connected you may need to pass additional selection parameters to GetMouseIndex to select which mouse -- unless you are using Windows in which case there is not way of distinguishing different mice.

Btw. you are not using the most precise timing, see comments below in code.
-mario

I would be incredibly grateful for any pointers. Thank you in advance!



                                [Image displayed on screen]

                                KbQueueFlush;
                                imagetime=GetSecs;

-> No, instead assign the Screen('Flip') timestamp as [~, imagetime] = Screen('Flip', ...) above.

                                WaitSecs(0.5); %half second delay before shock

-> More precise would be WaitSecs('UntilTime', imagetime + 0.5);
                    
                                [Code for shock delivery]      
                                   
                                [pressed, firstPress]=KbQueueCheck; %check if any key was pressed
                                    if pressed %if key was pressed do the following
                                       firstPress(find(firstPress==0))=NaN; %little trick to get rid of 0s
                                       [endtime, Index]=min(firstPress); % gets the RT of the first key-press and its ID
                                       keyname=KbName(Index); %converts KeyID to keyname
                                       rt=endtime-imagetime; %reaction time
                                    else
                                       rt=1000; %reactiontime set to 1000 indicating there was no response
                                       keyname = 'NoKeyPress';
                                    end