Motor imagery is increasingly used as a plasticity-booster to complement conventional rehabilitation. Here the investigators test the hypothesis that the combination of mental training with conventional rehabilitation may speed up the recovery in patients with total knee arthroplasty. The investigators also characterize the brain correlates of such recovery with imagery tasks for virtual reality environments.

Inclusion Criteria:

• Right handed
• No contraindication to the fMRI exam

Exclusion Criteria:

• Contraindication to the fMRI exam

Experimental group (MI training): 24 candidates to TKA (aged between 45 and 65 years) will undergo a specific MI training during the period of post-surgical rehabilitation, in addition to the usual physical rehabilitation.

Control group 1 (non-specific cognitive training): 24 candidates to TKA will undergo a non-specific cognitive treatment during the period of post-surgical rehabilitation, in addition to the usual physical rehabilitation.

Control group 2: 48 subjects with similar demographic characteristics to those of the previous two groups will be evaluated with the same cognitive/fMRI paradigm to assess in TKA candidates the presence of anomalies of cortical organization of the motor system in the pre-surgical phase.