Chimpanzee brain morphometry utilizing standardized MRI preprocessing and macroanatomical annotations.

Sam Vickery,Felix Hoffstaedter,Robert D Latzman,Svenja Caspers,Chet C Sherwood,Steven J Schapiro,Robert Dahnke,Christian Gaser,Simon B Eickhoff,William D Hopkins

doi:10.7554/elife.60136

Abstract

Chimpanzees are among the closest living relatives to humans and, as such, provide a crucial comparative model for investigating primate brain evolution. In recent years, human brain mapping has strongly benefited from enhanced computational models and image processing pipelines that could also improve data analyses in animals by using species-specific templates. In this study, we use structural MRI data from the National Chimpanzee Brain Resource (NCBR) to develop the chimpanzee brain reference template Juna.Chimp for spatial registration and the macro-anatomical brain parcellation Davi130 for standardized whole-brain analysis. Additionally, we introduce a ready-to-use image processing pipeline built upon the CAT12 toolbox in SPM12, implementing a standard human image preprocessing framework in chimpanzees. Applying this approach to data from 194 subjects, we find strong evidence for human-like age-related gray matter atrophy in multiple regions of the chimpanzee brain, as well as, a general rightward asymmetry in brain regions.

Highlights

Chimpanzees (Pan troglodytes) along with bonobos (Pan paniscus) represent the closest extant relatives of humans sharing a common ancestor approximately 7–8 million years ago (Langergraber et al, 2012)
To enable more direct comparison to previous research, we manually created the Davi130 parcellation, a whole brain macroanatomical annotation based on the Juna T1 template
On top of the regions identified by region-wise morphometry, we found extensive voxel-wise effects throughout the orbitofrontal cortex (OFC), inferior temporal gyrus (ITG), transverse temporal gyrus (TTG), frontal operculum (FOP), parietal operculum (POP), postcentral gyrus (PoCG), supramarginal gyrus (SMG), angular gyrus (AnG), and in parts of the superior parietal lobule (SPL), superior occipital gyrus, and in inferior parts of the cerebellum

Summary

Introduction

Chimpanzees (Pan troglodytes) along with bonobos (Pan paniscus) represent the closest extant relatives of humans sharing a common ancestor approximately 7–8 million years ago (Langergraber et al, 2012). Neuroscience recognition (Anderson and Gallup, 2015; Hecht et al, 2017) and some basic elements of language (Savage-Rumbaugh, 1986; Savage-Rumbaugh and Lewin, 1994; Tomasello and Call, 1997) like conceptual metaphorical mapping (Dahl and Adachi, 2013) This cognitive complexity together with similar neuroanatomical features (Zilles et al, 1989; Rilling and Insel, 1999; Gomez-Robles et al, 2013; Hopkins et al, 2014; Hopkins et al, 2017) and genetic proximity (Waterson et al, 2005) renders these species unique among non-human primates to study the evolutional origins of the human condition. Numerous studies using magnetic resonance imaging (MRI) have compared relative brain size, shape, and gyrification in humans and chimpanzees (Zilles et al, 1989; Rilling and Insel, 1999; Gomez-Robles et al, 2013; Hopkins et al, 2014; Hopkins et al, 2017)

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