Passing data using handles in GUI in functions with for loops?

I can't quite figure out what I am doing wrong here. My function is long and has a number of variables that are working properly, so I focused on the important bits below. Upon GUI initialization, I create an array of zeros that I look to change values in later:

handles.ActiveCheck = zeros(1,64);
guidata(hObject,handles);

I then have a callback function based on a togglebutton that functions as a while loop while the program is running; this loop checks if a given value in the previously defined ActiveCheck is 1:

    while true
        for channel = [2,5,7]
            if ActiveCheck(channel) = 1
               plot(x)
            end
        end
    end

Finally, I have a callback function for a checkbox (I have many checkboxes) that simply changes a given value in the array to 1:

handles.ActiveCheck(2) = 1
guidata(hObject,handles)

The problem I am running into is that while the checkbox callback is successfully changing the value to 1 at the given position, this change does not hold and is not seen by the looping while function.

[Daniel Henry]

Nick, did you ever figure out a solution to this problem? I'm running into a similar issue right now.