Matlab: link to variable, not variable value

It has been very difficult to use google, MATLAB documentation, I've spent a few hours, and I cannot learn how to

x = 1
y = x
x = 10
y

ans = 10

what happens instead is:

x = 1
y = x
x = 10
y

ans = 1

The value of x is stored into y. But I want to dynamically update the value of y to equal x.

What operation do I use to do this?

Thanks.M