[R] Repeated Measures Regression

[Andreas Pedroni]

Dear list, 

I'm trying to calculate a regression on a dataset with repeated measures. I tried to look for an example on the web and in Pinheiro and Bates "Mixed-Effects Models in .. " book.
However, I' m not sure wether the regression model I'm using is the "right" one. I'm very thankful for any suggestions!
Ok, here's what I'm trying to do:
First, the experimental design:
We ran a study, where 36 subjects played a game, where they could 150 times make risky decisions. Throughout the game we recorded physiological data. 
Thus, each subject made in every trial a more or less risky decision. Now, I'm interested, whether parameters of the physiological data (Phys1, Phys2) can predict the amount of risk taken by a subject. 

So far my regression model looks as follows:

lme(Risk ~ Phys1 + Phys2, random = ~ 1  |  Subject)

Could this be suitable? Is it a problem, if the Variable Risk is autocorrelated within Subjects?

Thank you very much for any help and sorry if this is a too trivial question for the list.

Kind regards 

Andreas Pedroni