I would use either. "Our" in "our minds" is the normal 1st person plural; "our" in "our mind" relates to the impersonal "we" which "we" use in much the same way as "one", to mean "any person".
Thus in the plural version, the reference is to the minds of all of us; whereas in the singular version, the reference is to any particular mind.
Here's an example from Hume's Enquiry Concerning Human Understanding:
1. It must, however, be confessed, that this species of scepticism, when more moderate, may be understood in a very reasonable sense, and is a necessary preparative to the study of philosophy, by preserving a proper impartiality in our judgements, and weaning our mind from all those prejudices