Shading an area across zero

I have a plot of zscores and would like to highlight a particular area of the graph. This is the relevant code i'm using:

xmin = plot_time-time_period; xmax = plot_time; %called from a matrix
x = [xmin xmax];
yLimits = get(gca,'YLim');

h1 = area(x,[yLimits(1) yLimits(1)]);
h2 = area(x,[yLimits(2) yLimits(2)]);

set(h1,'Facecolor','k')
set(h2,'Facecolor','k')
alpha(0.15)

Which produces this:

I would like to remove the line across zero, but the following code just creates nonsense:

h1 = area(x,[yLimits(1) yLimits(2)]);

Any ideas? Thanks.

Answer 1

[Doug Hull]

I think you are looking for this:

MATLAB CENTRAL FILE EXCHANGE

Answer 2

[Meg Wang]

set(h1, 'ShowBaseLine', 'off')