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Reilly OT, Brosnan SF, Benítez ME, Phillips KA, Hecht EE. Sex differences in white matter tracts of capuchin monkey brains. J Comp Neurol 2023; 531:1096-1107. [PMID: 37127839 PMCID: PMC10247455 DOI: 10.1002/cne.25480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 05/03/2023]
Abstract
Nonhuman primates exhibit sexual dimorphism in behavior, suggesting that there could be underlying differences in brain organization and function. Understanding this neuroanatomical variation is critical for enhancing our understanding of the evolution of sex differences in the human brain. Tufted capuchin monkeys (Sapajus [Cebus] apella) represent a phylogenetically diverse taxa of neotropical primates that converge on several behavioral characteristics with humans relevant to social organization, making them an important point of comparison for studying the evolution of sex differences in primates. While anatomical sex differences in gray matter have previously been found in capuchin monkeys, the current study investigates sex differences in white matter tracts. We carried out tract-based spatial statistical analysis on fractional anisotropy images of tufted capuchin monkeys (15 female, 5 male). We found that females showed significantly higher fractional anisotropy than males in regions of frontal-parietal white matter in the right cerebral hemisphere. Paralleling earlier findings in gray matter, male and female fractional anisotropy values in these regions were nonoverlapping. This complements prior work pointing toward capuchin sex differences in limbic circuitry and higher-order visual regions. We propose that these sex differences are related to the distinct socioecological niches occupied by male and female capuchins. Capuchin neuroanatomical sex differences appear to be more pronounced than in humans, which we suggest may relate to human adaptations for prolonged neurodevelopmental trajectories and increased plasticity.
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Affiliation(s)
- Olivia T Reilly
- Department of Psychology, Georgia State University, Atlanta, Georgia
- Language Research Center, Georgia State University, Atlanta, Georgia
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Sarah F Brosnan
- Department of Psychology, Georgia State University, Atlanta, Georgia
- Language Research Center, Georgia State University, Atlanta, Georgia
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia
- Neuroscience Institute, Georgia State University, Atlanta, Georgia
| | - Marcela E Benítez
- Language Research Center, Georgia State University, Atlanta, Georgia
- Department of Anthropology, Emory University, Atlanta, Georgia
| | - Kimberley A Phillips
- Department of Psychology, Trinity University, San Antonio, Texas
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas
| | - Erin E Hecht
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts
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Croxson PL, Forkel SJ, Cerliani L, Thiebaut de Schotten M. Structural Variability Across the Primate Brain: A Cross-Species Comparison. Cereb Cortex 2019; 28:3829-3841. [PMID: 29045561 DOI: 10.1093/cercor/bhx244] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 11/13/2022] Open
Abstract
A large amount of variability exists across human brains; revealed initially on a small scale by postmortem studies and, more recently, on a larger scale with the advent of neuroimaging. Here we compared structural variability between human and macaque monkey brains using grey and white matter magnetic resonance imaging measures. The monkey brain was overall structurally as variable as the human brain, but variability had a distinct distribution pattern, with some key areas showing high variability. We also report the first evidence of a relationship between anatomical variability and evolutionary expansion in the primate brain. This suggests a relationship between variability and stability, where areas of low variability may have evolved less recently and have more stability, while areas of high variability may have evolved more recently and be less similar across individuals. We showed specific differences between the species in key areas, including the amount of hemispheric asymmetry in variability, which was left-lateralized in the human brain across several phylogenetically recent regions. This suggests that cerebral variability may be another useful measure for comparison between species and may add another dimension to our understanding of evolutionary mechanisms.
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Affiliation(s)
- Paula L Croxson
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L Levy Place, New York, NY, USA
| | - Stephanie J Forkel
- Centre for Neuroimaging Sciences, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Natbrainlab, Department Forensics and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Leonardo Cerliani
- Brain Connectivity and Behaviour group, Brain and Spine Institute, Paris, France.,Frontlab, Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France
| | - Michel Thiebaut de Schotten
- Brain Connectivity and Behaviour group, Brain and Spine Institute, Paris, France.,Frontlab, Institut du Cerveau et de la Moelle épinière (ICM), UPMC UMRS 1127, Inserm U 1127, CNRS UMR 7225, Paris, France
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Krishnan C. Learning and interlimb transfer of new gait patterns are facilitated by distributed practice across days. Gait Posture 2019; 70:84-89. [PMID: 30831544 PMCID: PMC6474794 DOI: 10.1016/j.gaitpost.2019.02.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 02/02/2023]
Abstract
BACKGROUND Previous studies have shown that the extent to which learning with one limb transfers to the opposite, untrained limb (i.e., interlimb transfer) is proportional to the amount of prior learning (or skill acquisition) that has occurred in the training limb. Thus, it is likely that distributed practice-a training strategy that is known to facilitate learning-will result in greater interlimb transfer than massed practice. RESEARCH QUESTION To evaluate the effects of massed and distributed practice on acquisition and interlimb transfer of leg motor skills during walking. METHODS Forty-five subjects learned a new gait pattern that required greater hip and knee flexion during the swing phase of gait. The new gait pattern was displayed as a foot trajectory in the sagittal plane and participants attempted to match their foot trajectory to this template. Subjects in the massed practice group (n = 20) learned the task on a single day, whereas subjects in the distributed practice group (n = 25) learned the task that was spaced over two consecutive days (training phase). Following completion of training, subjects in both groups practiced the task with their untrained, opposite leg to evaluate interlimb transfer (transfer phase). RESULTS Results indicated that the amount of skill acquisition (i.e., reductions in tracking error) on the training leg was significantly higher (P < 0.05) in the distributed practice group when compared with the massed practice group. Similarly, the amount of interlimb transfer was also significantly higher (P < 0.05) in the distributed practice group both at the beginning and end of the transfer phase. SIGNIFICANCE The findings indicate that acquisition and interlimb transfer of leg motor skills are significantly greater when the task was learned using distributed practice, which may have implications for gait rehabilitation in individuals with unilateral deficits, such as stroke.
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Affiliation(s)
- Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, Michigan Medicine, Ann Arbor, MI, USA,Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA,Michigan Robotics Institute, University of Michigan, Ann Arbor, MI, USA,School of Kinesiology, University of Michigan, Ann Arbor, MI, USA,Address for Correspondence: Chandramouli Krishnan, PT, PhD, Director, Neuromuscular & Rehabilitation Robotics Laboratory (NeuRRo Lab), Department of Physical Medicine and Rehabilitation, Michigan Medicine, University of Michigan, 325 E Eisenhower Parkway (Suite 3013), Ann Arbor, MI – 48108, Phone: (319) 321-0117, Fax: (734-615-1770),
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Hopkins WD, Hopkins AM, Misiura M, Latash EM, Mareno MC, Schapiro SJ, Phillips KA. Sex differences in the relationship between planum temporale asymmetry and corpus callosum morphology in chimpanzees (Pan troglodytes): A combined MRI and DTI analysis. Neuropsychologia 2016; 93:325-334. [PMID: 27055947 PMCID: PMC5050170 DOI: 10.1016/j.neuropsychologia.2016.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/23/2016] [Accepted: 04/03/2016] [Indexed: 12/31/2022]
Abstract
Increases brain size has been hypothesized to be inversely associated with the expression of behavioral and brain asymmetries within and between species. We tested this hypothesis by analyzing the relation between asymmetries in the planum temporale (PT) and different measures of the corpus callosum (CC) including surface area, streamline count as measured from diffusion tensor imaging, fractional anisotropy values and the ratio in the number of fibers to surface area in a sample of chimpanzees. We found that chimpanzees with larger PT asymmetries in absolute terms had smaller CC surface areas, fewer streamlines and a smaller ratio of fibers to surface area. These results were largely specific to male but not female chimpanzees. Our results partially support the hypothesis that brain asymmetries are linked to variation in corpus callosum morphology, although these associations may be sex-dependent.
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Affiliation(s)
- William D Hopkins
- Neuroscience Institute and Language Research Center, Georgia State University, Atlanta, GA 30302, USA; Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30329, USA.
| | - Anna M Hopkins
- Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30329, USA
| | - Maria Misiura
- Department of Psychology, Georgia State University, Atlanta, GA 30302, USA
| | - Elitaveta M Latash
- Neuroscience Institute and Language Research Center, Georgia State University, Atlanta, GA 30302, USA
| | - Mary Catherine Mareno
- Department of Veterinary Science, The University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Steven J Schapiro
- Department of Veterinary Science, The University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
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Boeving ER, Lacreuse A, Hopkins WD, Phillips KA, Novak MA, Nelson EL. Handedness influences intermanual transfer in chimpanzees (Pan troglodytes) but not rhesus monkeys (Macaca mulatta). Exp Brain Res 2014; 233:829-37. [PMID: 25466868 DOI: 10.1007/s00221-014-4158-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 11/20/2014] [Indexed: 11/30/2022]
Abstract
Intermanual transfer refers to an effect, whereby training one hand to perform a motor task improves performance in the opposite untrained hand. We tested the hypothesis that handedness facilitates intermanual transfer in two nonhuman primate species: rhesus monkeys (N = 13) and chimpanzees (N = 52). Subjects were grouped into one of four conditions: (1) left-handers trained with the left (dominant) hand; (2) left-handers trained with the right (nondominant) hand; (3) right-handers trained with the left (nondominant) hand; and (4) right-handers trained with the right (dominant) hand. Intermanual transfer was measured using a task where subjects removed a Life Savers(®) candy (monkeys) or a washer (chimpanzees) from metal shapes. Transfer was measured with latency by comparing the average time taken to solve the task in the first session with the trained hand compared to the first session with the untrained hand. Hypotheses and predictions were derived from three models of transfer: access: benefit training with nondominant hand; proficiency: benefit training with dominant hand; and cross-activation: benefit irrespective of trained hand. Intermanual transfer (i.e., shorter latency in untrained hand) occurred regardless of whether monkeys trained with the dominant hand or nondominant hand, supporting the cross-activation model. However, transfer was only observed in chimpanzees that trained with the dominant hand. When handedness groups were examined separately, the transfer effect was only significant for right-handed chimpanzees, partially supporting the proficiency model. Findings may be related to neurophysiological differences in motor control as well as differences in handedness patterning between rhesus monkeys and chimpanzees.
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Affiliation(s)
- Emily R Boeving
- Department of Psychology, Florida International University, 11200 SW 8th Street, DM 256, Miami, FL, 33199, USA
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