ScannerSyncMatlab - MRC CBU Imaging Wiki

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Using ScannerSync from Matlab

Make sure you have the ScannerSync control installed.

Somewhere near the top of your code, set up ScannerSync & initialise communication with the input-output board (will not work if you're using a machine without the board, e.g., not the mimic or stim delivery machines). 

%% SCANNERSYNC
TR=1000; % TR in ms
numdummies=8; 

% Create & initialise scanner sync object
objSS=actxserver('MRISync.ScannerSync');  %Create a scanner object
invoke(objSS,'Initialize','') %Initialise the Keithley board and object
invoke(objSS,'SetMSPerSample',2); %Set StartExperiment routines’ sampling

Now, wait for first pulse from scanner. Also, tell ScannerSync the approximate TR. 

% ScannerSync - waits for the first pulse, resets timer to 0, sets TR
invoke(objSS,'StartExperiment', double(TR));

Wait for dummies (one less as StartExperiment command above will already have heard a pulse) 

for countdown=(numdummies-1):-1:1
    count_text=sprintf('%d', countdown);
  % uncomment the next two if you're using the PsychToolbox
%    DrawFormattedText(window, count_text, 'center', 'center', white);
%    Screen(window, 'Flip');
    invoke(objSS,'SynchroniseExperiment',1,0); %  1= force wait for actual pulse; 0=return this many ms after pulse
end;

In your trial loop, you'll need to spend some of the time listening for pulses 

    invoke(objSS,'CheckPulseSynchronyForTime', double(500)); % spend 500 ms listening for any pulses

You should dump out the timing of critical events and the measured TR 

    picstarttime=invoke(objSS,'SSGetTimer');
    measuredTR=invoke(objSS,'GetMeasuredTR');

% ...add your own code to write these to your output file

Also, for some designs you may want to occasionally synchronise your trials to the scanner 

    invoke(objSS,'SynchroniseExperiment',1,0); %  1= force wait for actual pulse; 0=return this many ms after pulse