Paypal userinfo only returns user_id

Question

I am working with vb.net web application. I want to get papyal user info by paypal credential. My code below:

Dim url As String = "https://api.sandbox.paypal.com/v1/oauth2/token/userinfo?schema=openid"
            Dim req As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest)
            req.ContentType = "application/json"
            req.Headers.Add("Authorization", accesstoken)
            req.Method = "GET"
            Dim responseData As String = ""
            Dim Response As HttpWebResponse = DirectCast(req.GetResponse(), HttpWebResponse)
            Using reader As StreamReader = New StreamReader(Response.GetResponseStream())
                responseData = reader.ReadToEnd()
            End Using

Response returns only User_id.

user_id: https://www.paypal.com/webapps/auth/identity/user/.............

But want to get all information of user. How it possible?