117 CEREBRAL ADAPTATION ASSOCIATED WITH PERIPHERAL NERVE RECOVERY IN NA 6 the multidisciplinary rehabilitation group received a diagnostic visit at our outpatient Plexus Clinic resulting in a personalized rehabilitation treatment advice and plan. This was followed by a 16-week outpatient multidisciplinary rehabilitation program carried out in 4 weekly treatment sessions followed by 2 sessions every other week and two monthly sessions. Each of these 8 treatment sessions involved 1 hour of physical therapy and 1 hour of occupational therapy, with both disciplines working closely together, exchanging clinical findings and strategies when possible and appropriate to advance the treatment process. The multidisciplinary rehabilitation program combines motor learning principles to normalize scapular stability and coordination with self-management strategies for pain and fatigue to enable daily occupations and reduce persisting pain and fatigue. 1, 6, 124 The focus and extent to which each of these components were addressed within the intervention depended on individual patient needs. Patients in the usual care group received their usual care for 17 weeks, which differed per patient, consisting of no (reported) therapy (n = 6), four (n = 1), ten (n =1) or thirteen (n = 1) times physical therapy, or 29 times physical therapy and 4 times occupational therapy (n =1). For one patient the content of usual care was unknown, as she was lost to follow-up. See also Supplementary Table 1 for details. We performed the same measurements in the same order at baseline and follow-up. All participants first completed the MRI session, which involved a structural scan, a restingstate functional MRI (fMRI) scan (data not included here), and a task-fMRI scan (see below). Following scanning, we performed several clinical assessments (see Lustenhouwer et al. 124) to quantify residual NA symptoms. Here, we focused on two of the clinical measures. First, patients completed the SRQ-DLV, which measured the functional capability of the upper extremity, where lower scores reflected more impairment (range 17-100). 34 Second, patients indicated how much pain they were currently experiencing on a visual analogue scale (VAS), which ranged from no pain to unbearable pain (0-100). 127 Experimental design All patients performed a hand laterality judgment task29 in the fMRI scanner. Patients had to indicate whether the stimulus (a white line drawing of a hand, presented on a black background), represented a left or a right hand by pressing a button with the big toe of the corresponding foot. They were instructed to respond as quickly and accurately as possible and to use their own hands as reference (such that they could imagine moving their limb to match the hand stimulus), without overt movement of their limb (compliance was checked with EMG over the thenar eminence of both hands). At the start of each block, participants assumed one of four possible postures (both hands palms facing down or up, or one hand palm down (left/right) and the other palm up (right/left)). Stimuli varied in LATERALITY (left, right), BIOMECHANICAL COMPLEXITY (complex, easy), and POSTURAL CONGRUENCY (congruent, incongruent) (see Figure 2). BIOMECHANICAL COMPLEXITY relates to the (imagined) movement needed to match the orientation of the own hand to that of the stimulus. Biomechanically complex trials (laterally oriented hands, rotated away from the body midline) typically elicit longer reaction times (RTs) and more brain activity in the fronto-parieto-occipital motor imagery network than biomechanically easy trials (medially oriented hands, rotated towards the body midline), even though the degree of rotation is matched. 25, 29 The POSTURAL CONGRUENCY