Arduino delay in MATLAB Gui

I want to turn on air pump when press the push button and it should automatically turn off after 3 seconds. I'm very begginer of MATLAB gui. So kindly request for answer.

function pushbutton1_Callback(hObject, eventdata, handles)

% hObject handle to pushbutton1 (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

global a;

writeDigitalPin(a,'D3',1);

pause(3);

But above code has problem it will never stop after 3 seconds