A neuroanatomical predictor of mirror self-recognition in chimpanzees.
The ability to recognize one's own reflection is shared by humans and only a few other species, including chimpanzees. However, this ability is highly variable across individual chimpanzees. In humans, self-recognition involves a distributed, right-lateralized network including frontal and parietal regions involved in the production and perception of action. The superior longitudinal fasciculus (SLF) is a system of white matter tracts linking these frontal and parietal regions. The current study measured mirror self-recognition (MSR) and SLF anatomy in 60 chimpanzees using diffusion tensor imaging. Successful self-recognition was associated with greater rightward asymmetry in the white matter of SLFII and SLFIII, and in SLFIII's gray matter terminations in Broca's area. We observed a visible progression of SLFIII's prefrontal extension in apes that show negative, ambiguous, and compelling evidence of MSR. Notably, SLFIII's terminations in Broca's area are not right-lateralized or particularly pronounced at the population level in chimpanzees, as they are in humans. Thus, chimpanzees with more human-like behavior show more human-like SLFIII connectivity. These results suggest that self-recognition may have co-emerged with adaptations to frontoparietal circuitry.
Center for Behavioral Neuroscience.|Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, GA, USA.
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EE
Hecht
Department of Psychology, Georgia State University, Atlanta, GA, USA.
L M
LM
Mahovetz
Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center.|Center for Translational Social Neuroscience.|Center for Behavioral Neuroscience, Emory University, Atlanta, GA, USA.
T M
TM
Preuss
Center for Behavioral Neuroscience.|Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center.|The Language Research Center, Georgia State University, Atlanta, GA, USA.|Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
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WD
Hopkins
D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D059907:Functional Neuroimaging; D066128:Gray Matter / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008297:Male; D009415:Nerve Net / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002679:Pan troglodytes / Q000033:anatomy & histology* / Q000523:psychology; D021641:Recognition, Psychology / Q000502:physiology*; D012649:Self Concept; D066127:White Matter / Q000033:anatomy & histology* / Q000000981:diagnostic imaging
brain evolution; chimpanzees; lateralization; self-recognition; superior longitudinal fasciculus