MATLAB: How to change a sound in a specific condition

Question

while 1
    brain=fread(bt)
   if (100<brain) && ( brain<150)
   disp ( 'attention')
elseif .....condition goes here
disp('meditation')
   end 
end

Answer 1

conditions_list = {'?', 'attention', 'meditation'};
while 1
    brain=fread(bt);
    if isempty(brain); break; end
    mask1 = (100<brain) & ( brain<150);
    mask2 = second_test_goes_here
    condition = ones(size(brain));
    condition(mask1) = 2;
    condition(mask2) = 3;
    brain_conditions = conditions_list(condition);
    disp( strjoin(brain_conditions, ' '));
end