Of course you need a dot like Azzi said. FYI, see this code to see how to adjust the line and markers:
x = 1:10;
y = sin(x);
plot(x, y, 'bo-', ...
'LineWidth', 4, 'MarkerSize', 20, ...
'MarkerFaceColor', 'r', 'MarkerEdgeColor', [.5, .9, .7]);
You should now be able to get lines between the markers and adjust the way the markers look. Hope this helps. See the help for LineSeries or plot for more options.