You have a few options for investigating high contributing methods in your web requests.
If you have a specific web request selected or you just sorted by response time and selected the top item you can use the PurePath hotspot (top right chart in the PurePaths dashlet) to quickly guide you to the segments of the PurePath that contributed the most time. The thicker the bar the more time was spent executing that function.
You can also right click on the PurePath and drill-down to the methods hotspots or methods dashlets. These will give you the list of methods involved in fulfilling the transactions and the hotspots will sort them by their response time contribution.