404. That’s an error.

The requested URL /bookmarks/mark?op=add&bkmk=http%3A//jn.physiology.org/content/106/2/589&title=Changes%20in%20reward%20contingency%20modulate%20the%20trial-to-trial%20variability%20of%20hippocampal%20place%20cells was not found on this server. That’s all we know.