Supplementary Material
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A
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Ek m an
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CBS - PiB Negative
CBS - PiB Positive
CBS - no PiB
AD
Supplementary Figure 1.
Performance on the ACE-R, Emotion-Selection, Ekman 60 and
TASIT tasks according to PiB status in CBS patients compared with AD.
Note. All scores are total percent correct. Each marker represents an individual patient’s score.
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To examine any potential differences in profile according to PiB status, we reanalysed the emotion processing data excluding the 2 CBS patients with PiB positive results. The main effect of Diagnosis remained significant on each of the four tasks (Face Perception: F (2,48) =
4.167, p = .021; Face Matching: F (2,48) = 3.470, p = .039; Emotion Matching: F (2,48) =
7.942, p = .001; Emotion Selection: F (2,48) = 13.331, p < .001), with the CBS patients performing below controls on the Face-Perception, Emotion-Matching and Emotion-
Selection tasks (all p values < .05), and worse than the AD group on the Emotion Selection task ( p = .019). On the Ekman 60, the main effect of Diagnosis was significant ( F (2,51) =
11.550, p < .001), with both patient groups performing worse than controls (CBS: p < .001;
AD: p = .003), although no difference in the level of impairment was seen between patient

2 groups. The overall effect of Emotion ( F (4,200) = 37.716, p < .001) and the interaction between Emotion and Diagnosis was also significant ( F (8,200) = 3.072, p = .003). On the
TASIT similar patterns of performance were observed, with an overall effect of Diagnosis present ( F (2,49) = 17.853, p < .001). Again, both CBS and AD patients performed worse than controls (both p values < .001), with no significant difference in performance seen between groups (both p values > .05). The main effect of Emotion was also significant
( F (5,222) = 10.551, p < .001), although no interaction between Emotion and Diagnosis was observed ( F (9,222) = 1.066, p > .05).
In summary, after excluding the two PiB positive patients, the general pattern of emotion processing deficits remained the same, with the exception of performance on the Emotion-
Selection task. On this task, the trend for CBS patients to perform worse than AD patients became significant, after PiB positive CBS patients were excluded. These analyses confirm that the two PiB positive patients were not performing substantially different from the PiB negative CBS cases on the emotion processing tasks.

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Supplementary Table 1. Correlations between emotion processing and cognitive/behavioural scores in CBS and AD.
CBS
Face-Perception
Face-Matching
ACE-R Digits-F Digits-B Trails A Naming Comprehension RCF-
Copy
.349
-.152
Emotion-Matching .234
Emotion-Selection .237
Ekman 60 .498
TASIT
AD
Face-Perception
Ekman 60
TASIT
.599
.470
Face-Matching .461
Emotion-Matching .535
Emotion-Selection .479
.265
.231
.524
.487
.477
.261
.265
.393
.329
.290
.327
.585
.532
.593
.132
.330
.738
.527
.288
.601
.354
.292
.305
.370
.287
.510
Note. Correlations are Pearson two-tailed. * p ≤ .001.
-.004
-.686
-.273
-.309
-.047
-.419
-.724
.078
-.222
-.001
-.187
-.566
.004
.519
.482
.463
.266
.301
-.254
.141
.412
.628
.470
.261
.703
.247
.456
.157
.022
.512
-.143
.190
.589
.774*
.590
.387
.867*
-.188
.145
-.310
-.090
.395
.634
.597
.460
.142
-.010
-.010
.268
.198
.053
.537
.459
.476
.096
-.079
-.023
-.245
-.088
.115
RCF-
Recall
CBI
Abnormal
Behaviour
CBI
Loss of
Motivation
.205
-.415
.169
.004
-.301
-.350
-.260
-.140
-.045
.062
-.169
-.060
.231
.074
.124
-.096
-.034
.065
.297
.433
.130
-.133
-.277
-.014

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Supplementary Figure 2. Patterns of cortical thinning in corticobasal syndrome
(CBS) and Alzheimer’s disease (AD). Regions in red/yellow show where patient groups have more cortical thinning compared to controls. The Alzheimer’s Disease vs. Corticobasal syndrome analysis shows regions where AD have more cortical thinning compared to CBS. No regions were identified where cortical thinning was greater in CBS than AD. Note. L = left hemisphere; R = right hemisphere.
Comparison of surface-based thickness (20mm FWHM smoothing). Statistical significance p < .001 (uncorrected for multiple comparisons).
Patterns of Cortical Thickness According to Diagnostic Group
Patients with CBS showed significant cortical thinning in the left insula, occipito– temporal gyrus, parieto-occipital sulcus and posterior lateral fissure as well as the right pre- and post-central gyri compared to controls. In AD, extensive bilateral cortical thinning was present involving the lateral and medial parietal cortices and medial temporal regions. Compared with AD, CBS patients showed less cortical thinning of the left anterior insula, superior temporal sulcus and middle temporal gyrus. No regions showed greater cortical thinning in CBS compared to AD.
Subcortical Volumes According to Diagnostic Group
Examination of subcortical volumes revealed a main effect of Diagnosis ( F (2,53) =
13.450, p < .001), with CBS ( p = .002) and AD ( p < .001) showing smaller

5 subcortical volumes than controls, but no overall differences between patient groups
( p > .05). Importantly, the interaction between region and diagnosis was significant
( F (6,160) = 4.309, p < .001). The interaction between hemisphere and region was also significant ( F (3,150) = 12.263, p < .011), although no other main or interaction effects according to hemisphere of the region were observed (all p values > .05). Post hoc analyses revealed that averaged across left and right hemispheres, the CBS group had smaller putamen ( p = .019), hippocampus ( p = .003) and nucleus accumbens ( p =
.001) compared to controls, whereas the AD group had smaller hippocampus ( p <
.001), amygdala ( p < .001), nucleus accumbens ( p < .001) and putamen ( p = .003). In addition, AD had smaller hippocampus ( p = .029) and amygdala ( p = .006) volumes compared to CBS.

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Supplementary Table 2. Regions of cortical thickness significantly associated with emotion processing in corticobasal syndrome and
Alzheimer’s disease groups combined.
Anatomical Location Side Cluster size
(mm 2 )
Ekman 60
Anterior cingulate Left 276.8
Number of vertices
Talairach coordinates t value p value Effect size
(Cohen’s d) x y z
501 -13.5 30.6 22.2 4.5 <0.0001 1.6
Effect size
(r)
0.63
TASIT
Anterior cingulate Left 16.6 27 -10.9 27.4 28.1 3.8 0.0008 1.4 0.59
Note. Effect size was computed according to the formula by Cohen. Clusters were thresholded at p < .001 (uncorrected for multiple comparisons). Coordinates and p values refer to the maximum vertex within the cluster.

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Supplementary Figure 3. Regions of cortical thickness significantly associated with emotion processing in corticobasal syndrome and Alzheimer’s disease groups combined at p < .001 (uncorrected for multiple comparisons).
FreeSurfer analyses were conducted to examine the regions associated with emotion processing across both groups, with diagnosis included as a nuisance variable, at p <
.001 uncorrected for multiple comparisons. The left anterior cingulate was significantly associated with performance on both the Ekman 60 and TASIT
(Supplementary Figure 3, Supplementary Table 2).

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Supplementary Table 3. Correlations between face processing and emotion recognition task performance and subcortical volumes.
Thalamus Caudate Putamen Pallidum Hippocampus
Left Right Left Right Left Right Left Right Left Right
Amygdala
Left Right
Accumbens
Left Right
Ekman 60
CBS .315 .354
AD .201 .295
.380
.292
.259
.188
.372
.286
.204
.318
.055
.061
-.001
.180
.415
.447
.325
.510*
.212
.334
.186
.418
.314
.257
.306
.425
Tasit
CBS .299 .420 .538* .412 .603* .479 .183 .131 .562* .477 .399 .371 .432 .448
AD .297 .447 .220 .136 .482* .469* .011 .174 .591* .582* .443 .493* .492* .466*
Note. Values are Pearson correlation values.
* p < .003 (Bonferroni correction). CBS = CBS and controls combined; AD = AD and controls combined.

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Supplementary Figure 4. A subset of scatterplots showing correlations between subcortical region volumes and emotion processing performance according to diagnostic group.