What do you mean by it does not work?? Are you getting an error? Are you not getting the expected result?
See this example below.
>> a = rand(128,6,3,352);
>> plot(a(:,1,1,352))
This is gives me the plot it's supposed to give.
Probably you might want to open a new figure window to make sure it is plotted on the fresh window, to do that,
figure
plot(a(:,1,1,352))
if it still "does not work", try,
data = a(:,1,1,352);
whos data
now you'll be able to see the properties of the extracted data.
