Supporting Information Delineating PFC across Species Here, we summarize evidence for inclusion of cortical areas in either our conservative (cytoarchitecturally granular/dysgranular) or liberal (agranular, but implicated in cognitive function) delineations of (PFC). Supplementary Tables 1 and 2 detail human and macaque areas, respectively, and include cytoarchitectural designations of granular (G), lightly granular (LG), dysgranular (D) or agranular (A) as reported by previous studies. Human areas correspond to those in the HCP_MMP1.0 parcellation1, while macaque areas are a composite of those from Ferry et al.2, Paxinos et al.3 and Lewis & Van Essen4 cytoarchitectural parcellations. Human Liberal PFC Delineations Decisions to include cytoarchitecturally agranular areas in our liberal PFC delineation were based on reports from previous studies implicating a given region in cognitive-related function. For humans, areal functional properties were primarily drawn from Glasser et al., 20161, which describes such properties in detail. An instructive starting example is human area 55b (26), which lies within a strip of premotor areas, but, on multiple grounds, can be considered part of liberal PFC. More specifically, area 55b is bounded by the frontal and premotor eye fields (FEF/PEF) medially and laterally, primary posteriorly (4), ventral (6v) and conservative PFC areas 8C and 8Av anteriorly. Area 55b exhibits several distinctive features: (1) light myelination compared to moderately myelinated FEF/PEF and heavily myelinated , (2) strong functional connectivity with a seed in language-related area PSL and (3) strong activation in contrasts of cognitive-related tasks relative to surrounding areas. Specifically, area 55b exhibited left lateralized activation in the LANGUAGE STORY & RELATIONAL-MATCH tasks and right lateralized activation in the social cognition (TOM-RANDOM) task (tasks and resulting parcellation are detailed in Glasser et al., 201631). Whether cortical area 55b meets architectonic criteria for dysgranular or granular cortex warrants closer examination, but we posit that its specific cognitive-related task contrasts warrant inclusion in our liberal delineation. Areas 44 and 45 correspond to Broca’s area (46, 47) and show strong activations in task contrasts LANGUAGE STORY and STORY-MATH. Area SFL (Superior Frontal Language) is part of the larger language network and shows functional activation in LANGUAGE STORY And RELATIONAL-MATCH contrasts. Areas IFJp and IFJa show greater activation in task contrasts TOM-RANDOM and FACES-SHAPES relative to posterior premotor neighbor 6r. Transitional areas i6-8 and s6-8 show gradual change in activation from posterior premotor cortex anteriorly, exhibiting relative activation during task contrasts compared to neighbors. Areas a24 and 24p exhibit relative deactivations for task contrasts LANGUAGE STORY, TOM-RANDOM and FACES-SHAPES relative to neighboring areas. Areas a32pr, d32, p32 and s32 show activations/deactivations relative to neighbors in MATH-STORYand/or FACES-SHAPES task contrasts and the LANGUAGE task category. Finally, area 25 is in an orbitofrontal region where functional imaging signal quality is reduced, however we believe that its adjacency to areas OFC and pOFC and similar structural properties merit its inclusion. Macaque Liberal PFC Delineations When considering agranular areas in the macaque , we consulted the literature for any evidence of cognitive-related function and attempted to maintain PFC designations among putatively homologous areas shared with humans (e.g. areas 24, 25 and 32). Area 24 is typically subdivided into areas 24a, 24b and 24c. While the Ferry et al.2 parcellation of these areas is limited in posterior extent due to study limitations, the Paxinos et al.3 whole-cortex parcellation allows continuation of these areas to their posterior extent. We first created composite versions of these two different parcellations, resulting in areas 24a’, 24b’ and 24c’. As described in Ferry et al.2, while these regions are generally considered to be part of the ‘medial prefrontal network,’ more posterior/dorsal portions could be considered part of premotor cortex. For this reason, we chose to subdivide these areas further into anterior and posterior portions, primarily guided by anterior-posterior delineations of adjacent dorsal areas. Although a finer- grained functional delineation of this region could help to refine our liberal PFC, we would like to stress that modifications of these areas are unlikely to change the ultimate conclusions drawn from this study. Medial areas 25 & 32 and orbitofrontal areas 13a and 14c, though cytoarchitecturally agranular, are outlined by Carmichael & Price5 as members of either cognitive or affect functional domains, and thus warrant inclusion in liberal PFC. Delineating Chimpanzee PFC Analysis of chimpanzee PFC architectonics was informed by comparisons of myelin maps and gradients with those in the human and macaque, but also by previously published cyto/myelo-architectonic studies/parcellations6,7. Chimpanzees share with humans and macaques the structural landmark of a heavily myelinated motor strip, the anterior dorsolateral border of which is marked with an arrow in main text Figure 2. Anterior to this border, one would expect to find premotor cortex corresponding to 6, followed more anteriorly by cognitive-related PFC. We assert that the pink contour in Fig. 2 represents a plausible candidate for a conservative delineation of chimpanzee PFC and note that it runs generally posterior to the genu-based border (white contour). We adapted Bailey et al.’s6 cytoarchitectonic map of chimpanzee cortex (Fig. S1, right) to a single chimpanzee subject using the atlas’ labeled coronal slices (Fig. S2). Bailey et al. color the motor strip along the precentral in yellow (area FA, equivalent to Brodmann area 4 in other primates), which corresponds with the heavily myelinated region (red) represented in our myelin map. Immediately rostral is premotor area FB (equivalent to Brodmann area 6), followed further rostrally by FC, which corresponds most closely to Brodmann area 8. Bailey et al.’s FB and FC correspond with the moderately myelinated regions (yellow/green) of our myelin maps immediately rostral to the motor strip. Putative were specifically labeled by Bailey et al. as FDΓ, which may correspond to the rostral-most finger of moderately myelinated frontal cortex most easily observed on an inflated surface (Fig S1, top row). By visual inspection, our cortical myelin-based PFC border shows good agreement with the premotor/prefrontal borders illustrated in Bailey et al.’s cytoarchitectonic map and Walker’s8 thalamocortical connectivity map.

Figure S1: A candidate boundary for conservative PFC in the chimpanzee. Maps of group-average chimpanzee cortical myelin maps (left) overlaid on group-average pial (i.e., folded) surfaces. The pink contour drawn on the surface serves as a candidate boundary for a conservative delineation of PFC. The genu-based PFC delineation is marked with a white contour for reference. Bailey et al.’s6 cytoarchitectonic findings are recreated (right) and its areal labels are mapped to the group-average surface for comparison. Data will be made available at https://balsa.wustl.edu/76Lm upon acceptance.

Figure S2: Mapping Bailey et al.6 cytoarchitectonic atlas to chimpanzee structural MRI. Left panel shows a recreation of a labeled obliquely-angled slice from Bailey et al.’s atlas, which was mapped to an individual chimpanzee subject (Edwina) that shared cortical folding patterns. Pink and green outlines in the MRI slice correspond to white matter and pial surface segmentations. Data will be made available at https://balsa.wustl.edu/67GG upon acceptance.

Cortical Thickness Maps Cortical thickness and gradient maps for each species are shown in Figure S3. To summarize our qualitative assessment: macaque dorsolateral frontal cortex has relatively thick anterior frontal cortex (green) and even thicker premotor/motor cortex (red) separated by a strip of thin cortex (blue). A similar pattern is discernible, though less pronounced, in the chimpanzee and perhaps also human. The macaque cortical thickness gradient (fourth row) more clearly illustrates the cortical thickness transitions on which the conservative and liberal PFC borders lie, though such a pattern is less obvious in the human and chimpanzee. Human anterior contains a prominently thick patch with corresponding anterior gradient ridges, however this pattern is less obvious in the chimpanzee and nonexistent in the macaque. However, cortical segmentation of this region was problematic in the nonhuman primate species, suggesting this may not reflect a neuroanatomically significant interspecies difference, but rather a methodological artifact. As with insular myelin content and gradients, all PFC delineations lie anterior to this region. Thickness maps in macaque medial frontal cortex include a patch of thick cortex posterior to the previously described myelin gradient ridge. In both macaque and human, relatively thin anteromedial frontal cortex becomes thicker posteriorly as it approaches the medial wall; the thicker posterior region is exclusive to our liberal PFC delineation.

Figure S3: Relation of cortical thickness to PFC delineations. Left hemisphere frontal cortex of each primate species displaying cortical thickness (first and third rows) and its corresponding spatial gradient (second and fourth rows). The white line overlying each map represents the group-average location of the coronal slice at the genu (see also main text Fig. 3); pink and blue lines represent group-average conservative and liberal PFC delineations, respectively. Data will be made available at https://balsa.wustl.edu/104j upon acceptance. Table S1: Human Cortical Areas Included in PFC Delineations

Area Name Studies (area if different) Histology G/D/A (Area if different) [Ref] 8Av P&P 99; P&W (8) G (8) [P&W]; D (8) [W 08] 8Ad P&P 99; P&W (8) G (8) [P&W]; D (8) [W 08] 8BL P&P 99 (8B); P&W (8) G (8) [P&W]; D (8) [W 08] [P&P 99] 8BM P&P 99 (8B); P&W (8) G (8) [P&W]; D (8) [W 08] [P&P 99] 8C P&P 99 (8Av); P&W (8) G (8) [P&W]; D (8) [W 08] 9a P&P 99 (9); P&W (9) G (9) [P&W]; G (9) [W 08] [P&P 99] 9m P&P 99 (9); P&W (9) G (9) [P&W]; G (9) [W 08] [P&P 99] 9p P&P 99 (9); P&W (9) G (9) [P&W]; G (9) [W 08] [P&P 99]

9-46d P&P 99; P&W (9/46) G (9/46) [P&W] a9-46v P&P 99; P&W (9/46) G (9/46) [P&W] p9-46v P&P 99; P&W (9/46) G (9/46) [P&W] 45 P&P 99

46 P&P 99

a47r P&P 99 (47/12); P&W (47) G (47) [P&W] 47l P&P 99 (47/12); P&W (47) G (47) [P&W] 47m P&P 99 (47/12); P&W (47) G (47) [P&W] 47s P&P 99 (47/12); P&W (47) G (47) [P&W] a24 P&W (24) A (24) [P&W]; A (24/AC) [W 08] p24 P&W (24) A (24) [P&W]

44 P&P 99 G/A [W 08]; G [P&P 01] a10p P&P 99 (10); P&W (10) G (10) [P&W]; G (10p) [W 08] p10p P&P 99 (10); P&W (10) G (10) [P&W]; G (10p) [W 08] 10r P&P 99 (10); P&W (10) G (10) [P&W]; G (10r) [W 08] 10v P&P 99 (10); P&W (10) G (10) [P&W]; G (10p, 10r, 10m) [W 08] 10d P&P 99 (10); P&W (10) G (10) [P&W]; G (10p, 10r, 10m) [W 08] 10pp P&P 99 (10); P&W (10) G (10) [P&W]; G (10p) [W 08] 11l P&P 99 (11); P&W (11) G (11) [P&W]; G (11I) [W 08]

13l P&P 99 (13); P&W (rostral 13) D [O]; G (Rostral 13) [P&W] G (11, rostral 13 + 14), A (caudal 13 + 14, agranular insular cortex) [P&W]; OFC P&P 99 (11,13,14); P&W (11, 13, 14) LG (11m), D/A (13l, 13m, 13b), A (13a, 14c) [W 08] G (11, rostral 13 + 14), pOFC P&P 99 (13,14); P&W (rostral 13 + 14; caudalA (caudal 13 + 14) 13 + 14, agranular insular cortex) [P&W]

25 A (25/IL) [W 08] a32pr P&W (32) A (32) [P&W]; A (32/AC, 32/PL) [W 08] d32 P&W (32) A (32) [P&W]; A (32/AC, 32/PL) [W 08] p32 P&W (32) A (32) [P&W]; A (32/AC, 32/PL) [W 08] s32 P&W (32) A (32) [P&W]; A (32/AC, 32/PL) [W 08] p47r P&P 99 (47/12); P&W (47) G (47) [P&W] IFSa IFSp 55b i6-8 IFJa IFJp SFL s6-8 Conservative PFC areas colored in red; Liberal PFC areas colored in blue. Histological abbreviations: G – granular; LG – lightly granular; D – dysgranular; A – agranular. Reference abbreviations: P&P 99 – Petrides & Pandya, 19999; P&P 02 – Petrides & Pandya, 200210; P&W – Passingham & Wise, 201211; W 08 – Wise, 200812. Table S2: Macaque Cortical Areas Included in PFC Delineations

PFC Area Primary Atlas Areas Studies (area name if different) Histology G/D/A (Area if different) [Ref] 8av 8av_PHT00 P&P; P&W (8) G (8) [P&W] 8ad 8ad_PHT00 P&P; P&W (8) G (8) [P&W] 8b 8b_PHT00 P&P; P&W (8) G (8) [P&W]

9l 9l_PHT00 P&P (9); P&W (9) G (9) [P&W]; G (9) [W 08] 9m 9m_PHT00 P&P (9); P&W (9) G (9) [P&W]; G (9) [W 08]

8/32 8/32_PHT00 P&P (8, 32); P&W (8, 32) G (8), A (32) [P&W]; A (32/PL) [W 08] 9/32 9/32_PHT00 P&P (9, 32); P&W (9, 32) G (9), A (32) [P&W]; G (9), A (32/PL) [W 08] 9/46 9/46_PHT00 P&P; P&W (9/46) G (9/46) [P&W] 9/46d 9/46d_PHT00 P&P; P&W (9/46) G (9/46) [P&W] 9/46v 9/46v_PHT00 P&P; P&W (9/46) G (9/46) [P&W] 44 44_PHT00 F 11 D [F 11] 45a 45a_PHT00 P&P; P&W (45) G (45) [P&P]; G (45) [P&W] 46d_pr 46d_PHT00 P&P (46); P&W (46) G (46) [P&W] 46v_pr 46v_PHT00 P&P (46); P&W (46) G (46) [P&W]

24aa 24a_FOA00; 24a_PHT00 P&P (24, 'frontal'); P&W (24) A [C&P]; A (24) [P&W]; A (24a/AC) [W 08]

24c 24c_PHT00 C&P A [C&P] 10d_pr 10d_PHT00 P&P (10); P&W (10) G [C&P];G (10) [P&W]; G (10m, 10o) [W 08] 10m_pr 10m_FOA00; 10m_PHT00 P&P (10); P&W (10) G [C&P]; G (10) [P&W]; G [W 08] 10o_pr 10o_FOA00; 10o_PHT00 P&P (10); P&W (10) G [C&P]; G (10) [P&W]; G (10m, 10o) [W 08]

11l 11l_FOA00 P&P (11); P&W (11) G [C&P]; G (11) [P&W]; G [W 08] 11m 11m_FOA00 P&P (11); P&W (11) G [C&P]; G (11) [P&W]; G [W 08] 12l_pr 12l_FOA00; 47(12)L_PHT00 P&P (47/12); P99 G [C&P] 12m 12m_FOA00 P&P (47/12); P99 G [C&P] 12o 12o_FOA00 P&P (47/12); P99 D [C&P] 12r_pr 12r_FOA00; 47(12)_PHT00 P99 D [C&P] 13l 13l_FOA00 P&P (13); P&W (13) D [C&P]; G (rostral 13), A (caudal 13) [P&W]; LG [W 08] 13m 13m_FOA00 P&P (13); P&W (13) D [C&P]; G (rostral 13), A (caudal 13) [P&W]; LG [W 08] 13b 13b_FOA00 C&P D [C&P] D [C&P]; G (rostral 14), A (caudal 14) [P&W]; 14r 14r_FOA00 P&P (14); P&W (14) LG (14r), A (14c) [W 08] 13a 13a_FOA00 P&P (13); P&W (13) A [C&P] G (rostral 13), A (caudal 13) [P&W]; A [W 08] A [C&P]; G (rostral 14), A (caudal 14) [P&W]; 14c 14c_FOA00 P&P (14); P&W (14) LG (14r), A (14c) [W 08] 24ba 24b_FOA00; 24b_PHT00 P&P (24, 'frontal'); P&W (24) A [C&P]; A (24) [P&W]; A (24b/AC) [W 08] 25 25_FOA00 P&P; P&W A [P&W]; A (25/IL) [W 08] 32_pr 32_FOA00; 32_PHT00 P&P ('frontal'); P&W A [C&P]; A [P&W]; A (32/PL) [W 08] Conservative PFC areas colored in red; Liberal PFC areas colored in blue. Histological abbreviations: G – granular; LG – lightly granular; D – dysgranular; A – agranular. Reference abbreviations: C&P – Carmichael & Price, 19945; F 11 – Frey et al., 201113; P&P – Petrides & Pandya, 200210; P&W – Passingham & Wise, 201211; W 08 – Wise, 200812. Table S3: Mean Cortical Gray Matter Volumes & Standard Deviations

MEAN GM VOLUME [cm^3] Total LR AntGenu LR Lib LR Cons LR Total L Total R AntGenu L AntGenu R Lib L Lib R Cons L Cons R AntGenu % Lib % Cons % Human 512.7 (55.0) 77.2 (11.1) 131.0 (15.5) 105.2 (13.2) 253.2 (28.1) 259.5 (27.8) 37.7 (5.7) 39.5 (5.8) 64.8 (7.7) 66.2 (8.0) 52.0 (6.5) 53.3 (6.9) 15% 26% 21% Chimp 133.5 (12.9) 18.5 (2.6) 23.2 (2.4) 67.3 (6.5) 66.2 (6.5) 9.2 (1.3) 9.3 (1.4) 11.5 (1.2) 11.7 (1.3) 14% 17% Macaque 34.4 (2.9) 3.3 (0.5) 4.8 (0.6) 4.4 (0.5) 17.2 (1.5) 17.1 (1.5) 1.6 (0.2) 1.7 (0.3) 2.3 (0.3) 2.5 (0.3) 2.1 (0.2) 2.2 (0.3) 10% 14% 13% Table S4: Mean Cortical Surface Areas & Standard Deviations

MEAN SURF. AREA [cm^2] Total LR AntGenu LR Lib LR Cons LR Total L Total R AntGenu L AntGenu R Lib L Lib R Cons L Cons R AntGenu % Lib % Cons % Human 1,842.6 (195.9) 287.0 (40.1) 460.7 (55.2) 377.1 (48.0) 917.3 (97.8) 925.3 (98.4) 140.9 (20.0) 146.1 (21.0) 229.5 (27.2) 231.2 (28.2) 187.7 (23.4) 189.4 (24.9) 16% 25% 20% Chimp 599.4 (53.1) 71.9 (10.2) 84.9 (8.2) 301.1 (26.0) 298.3 (27.2) 35.5 (5.1) 36.4 (5.4) 41.7 (4.0) 43.1 (4.3) 12% 14% Macaque 193.3 (13.2) 19.1 (2.3) 25.7 (2.4) 22.8 (2.1) 96.7 (6.7) 96.7 (6.6) 9.4 (1.2) 9.7 (1.2) 12.3 (1.1) 13.4 (1.2) 10.9 (1.0) 11.8 (1.1) 10% 13% 12% Table S5: Cortical Thickness

MEAN THICKNESS [mm] Total LR AntGenu LR Lib LR Cons LR Total L Total R AntGenu L AntGenu R Lib L Lib R Cons L Cons R Human 2.7 (0.1) 2.7 (0.1) 2.8 (0.1) 2.7 (0.1) 2.7 (0.1) 2.7 (0.1) 2.7 (0.1) 2.8 (0.1) 2.8 (0.1) 2.8 (0.1) 2.7 (0.1) 2.8 (0.1) Chimp 2.6 (0.1) 3.4 (0.1) 3.3 (0.1) 2.6 (0.1) 2.6 (0.1) 3.4 (0.1) 3.4 (0.1) 3.4 (0.1) 3.3 (0.1) Macaque 2.0 (0.1) 2.3 (0.1) 2.2 (0.1) 2.3 (0.1) 2.0 (0.1) 2.0 (0.1) 2.3 (0.1) 2.3 (0.1) 2.3 (0.1) 2.2 (0.1) 2.3 (0.1) 2.2 (0.1) Table S6: Mean Subcortical White Matter Volumes & Standard Deviations

MEAN WM VOLUME [cm^3] Total LR AntGenu LR Total L Total R AntGenu L AntGenu R AntGenu % Human 442.9 (61.7) 52.3 (10.2) 219.7 (30.6) 223.2 (31.2) 26.0 (5.1) 25.4 (5.3) 12% Chimp 119.4 (12.0) 8.5 (1.9) 59.9 (6.1) 59.5 (6.0) 4.2 (0.9) 4.3 (1.0) 7% Macaque 21.8 (2.5) 1.1 (0.2) 10.9 (1.2) 11.0 (1.3) 0.5 (0.1) 0.6 (0.1) 5% Table S7: Area V1 Cortical Volume & Standard Deviations

MEAN V1 GM VOL. [cm^3] Total LR Total L Total R V1 % Human 14.0 (2.0) 7.0 (1.0) 7.0 (1.1) 3% Chimp 7.5 (0.8) 3.8 (0.4) 3.7 (0.4) 6% Macaque 3.7 (0.4) 1.9 (0.2) 1.8 (0.2) 11% Table S8: Area V1 Cortical Surface Area & Standard Deviations

MEAN V1 SURF AREA [cm^2] Total LR Total L Total R V1 % Human 69.7 (9.4) 34.9 (4.9) 34.9 (5.0) 4% Chimp 47.2 (4.7) 23.8 (2.3) 23.4 (2.5) 8% Macaque 24.1 (2.0 12.4 (1.1) 11.7 (0.9) 12% Table S9: Area V1 Cortical Thickness & Standard Deviation

MEAN V1 THICKNESS [mm] Total LR Total L Total R Human 2.0 (0.1) 2.0 (0.1) 2.0 (0.1) Chimp 2.0 (0.2) 2.0 (0.2) 2.0 (0.2) Macaque 1.8 (0.1) 1.8 (0.1) 1.8 (0.1)

Supplementary Tables 3-9 provide values averaged over individual subjects (60 humans; 29 chimpanzees; 19 macaques). Standard deviations are provided in parentheses next to the average values. Provided percentages are of total cortex per measure. References 1. Glasser, M. F. et al. A multi-modal parcellation of human . Nature 1–11 (2016). doi:10.1038/nature18933 2. Ferry, A. T., Öngür, D., An, X. & Price, J. L. Prefrontal cortical projections to the striatum in macaque monkeys: Evidence for an organization related to prefrontal networks. J. Comp. Neurol. 425, 447–470 (2000). 3. Paxinos, G., Huang, X.-F. & Toga, A. The Rhesus Monkey Brain in Stereotaxic Coordinates. (Academic Press, 2000). 4. Lewis, J. W. & Van Essen, D. C. Mapping of architectonic subdivisions in the macaque monkey, with emphasis on parieto-occipital cortex. J. Comp. Neurol. 428, 79–111 (2000). 5. Carmichael, S. T. & Price, J. L. Architectonic subdivision of the orbital and medial prefrontal cortex in the macaque monkey. J. Comp. Neurol. 346, 366–402 (1994). 6. Bailey, P., Bonin, G. V. & McCulloch, W. S. The isocortex of the chimpanzee. (1950). 7. Walker, A. E. A cytoarchitectural study of the prefrontal area of the macaque monkey. J. Comp. Neurol. 73, 59–86 (1940). 8. Walker, A. E. The thalamus of the chimpanzee: IV. Thalamic projections to the cerebral cortex. J. Anat. 73, 37–93 (1938). 9. Petrides, M. & Pandya, D. N. Dorsolateral prefrontal cortex: comparative cytoarchitectonic analysis in the human and the macaque brain and corticocortical connection patterns. Eur. J. Neurosci. 11, 1011– 36 (1999). 10. Petrides, M. & Pandya, D. N. Comparative cytoarchitectonic analysis of the human and the macaque ventrolateral prefrontal cortex and corticocortical connection patterns in the monkey. Eur. J. Neurosci. 16, 291–310 (2002). 11. Passingham, R. E., & Wise, S. P. The neurobiology of the prefrontal cortex: anatomy, evolution, and the origin of insight. (2012). 12. Wise, S. P. Forward frontal fields: phylogeny and fundamental function. Trends Neurosci. 31, 599–608 (2008). 13. Frey, S. et al. An MRI based average macaque monkey stereotaxic atlas and space (MNI monkey space). Neuroimage 55, 1435–1442 (2011).