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Full-Text Articles in Psychology
Sex Differences In The Relationship Between Planum Temporale Asymmetry And Corpus Callosum Morphology In Chimpanzees (Pan Troglodytes): A Combined Mri And Dti Analysis, William D. Hopkins, A. M. Hopkins, M. Misiura, E. M. Latash, M. C. Mareno, S. J. Schapiro, Kimberley A. Phillips
Sex Differences In The Relationship Between Planum Temporale Asymmetry And Corpus Callosum Morphology In Chimpanzees (Pan Troglodytes): A Combined Mri And Dti Analysis, William D. Hopkins, A. M. Hopkins, M. Misiura, E. M. Latash, M. C. Mareno, S. J. Schapiro, Kimberley A. Phillips
Psychology Faculty Research
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 …
The Corpus Callosum In Primates: Processing Speed Of Axons And The Evolution Of Hemispheric Asymmetry, Kimberley A. Phillips, Cheryl D. Stimpson, J. B. Smaers, Mary Ann Raghanti, B. Jacobs, A. Popratiloff, Patrick R. Hof, Chet C. Sherwood
The Corpus Callosum In Primates: Processing Speed Of Axons And The Evolution Of Hemispheric Asymmetry, Kimberley A. Phillips, Cheryl D. Stimpson, J. B. Smaers, Mary Ann Raghanti, B. Jacobs, A. Popratiloff, Patrick R. Hof, Chet C. Sherwood
Psychology Faculty Research
Interhemispheric communication may be constrained as brain size increases because of transmission delays in action potentials over the length of axons. Although one might expect larger brains to have progressively thicker axons to compensate, spatial packing is a limiting factor. Axon size distributions within the primate corpus callosum (CC) may provide insights into how these demands affect conduction velocity. We used electron microscopy to explore phylogenetic variation in myelinated axon density and diameter of the CC from 14 different anthropoid primate species, including humans. The majority of axons were less than 1 µm in diameter across all species, indicating that …
Tractography Of The Spider Monkey (Ateles Geoffroyi) Corpus Callosum Using Diffusion Tensor Magnetic Resonance Imaging, D. Platas-Neri, S. Hidalgo-Tobón, B. De Celis Alonso, F. C-P De León, J. Muñoz-Delgado, Kimberley A. Phillips
Tractography Of The Spider Monkey (Ateles Geoffroyi) Corpus Callosum Using Diffusion Tensor Magnetic Resonance Imaging, D. Platas-Neri, S. Hidalgo-Tobón, B. De Celis Alonso, F. C-P De León, J. Muñoz-Delgado, Kimberley A. Phillips
Psychology Faculty Research
The objective of this research was to describe the organization, connectivity and microstructure of the corpus callosum of the spider monkey (Ateles geoffroyi). Non-invasive magnetic resonance imaging and diffusion-tensor imaging were obtained from three subjects using a 3T Philips scanner. We hypothesized that the arrangement of fibers in spider monkeys would be similar to that observed in other non-human primates. A repeated measure (n = 3) of fractional anisotropy values was obtained of each subject and for each callosal subdivision. Measurements of the diffusion properties of corpus callosum fibers exhibited a similar pattern to those reported in the …
Performance Asymmetries In Tool Use Are Associated With Corpus Callosum Integrity In Chimpanzees (Pan Troglodytes): A Diffusion Tensor Imaging Study, Kimberley A. Phillips, J. Schaeffer, E. A. Barrett, William D. Hopkins
Performance Asymmetries In Tool Use Are Associated With Corpus Callosum Integrity In Chimpanzees (Pan Troglodytes): A Diffusion Tensor Imaging Study, Kimberley A. Phillips, J. Schaeffer, E. A. Barrett, William D. Hopkins
Psychology Faculty Research
The authors examined the relationship of corpus callosum (CC) morphology and organization to hand preference and performance on a motor skill task in chimpanzees. Handedness was assessed using a complex tool use task that simulated termite fishing. Chimpanzees were initially allowed to perform the task wherein they could choose which hand to use (preference measure), then they were required to complete trials using each hand (performance measure). Two measures were used to assess the CC: midsagittal area obtained from in vivo magnetic resonance images and density of transcallosal connections as determined by fractional anisotropy values obtained from diffusion tensor imaging. …
Genetic Contributions To The Midsagittal Area Of The Corpus Callosum, Kimberley A. Phillips, J. Rogers, E. A. Barrett, D. C. Glahn, P. Kochunov
Genetic Contributions To The Midsagittal Area Of The Corpus Callosum, Kimberley A. Phillips, J. Rogers, E. A. Barrett, D. C. Glahn, P. Kochunov
Psychology Faculty Research
The degree to which genes and environment determine variations in brain structure and function is fundamentally important to understanding normal and disease-related patterns of neural organization and activity. We studied genetic contributions to the midsagittal area of the corpus callosum (CC) in pedigreed baboons (68 males, 112 females) to replicate findings of high genetic contribution to that area of the CC reported in humans, and to determine if the heritability of the CC midsagittal area in adults was modulated by fetal development rate. Measurements of callosal area were obtained from high-resolution MRI scans. Heritability was estimated from pedigree-based maximum likelihood …
Topography Of The Chimpanzee Corpus Callosum, Kimberley A. Phillips, William D. Hopkins
Topography Of The Chimpanzee Corpus Callosum, Kimberley A. Phillips, William D. Hopkins
Psychology Faculty Research
The corpus callosum (CC) is the largest commissural white matter tract in mammalian brains, connecting homotopic and heterotopic regions of the cerebral cortex. Knowledge of the distribution of callosal fibers projecting into specific cortical regions has important implications for understanding the evolution of lateralized structures and functions of the cerebral cortex. No comparisons of CC topography in humans and great apes have yet been conducted. We investigated the topography of the CC in 21 chimpanzees using high-resolution magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). Tractography was conducted based on fiber assignment by continuous tracking (FACT) algorithm. We expected …
Age-Related Differences In Corpus Callosum Area Of Capuchin Monkeys, Kimberley A. Phillips, Chet C. Sherwood
Age-Related Differences In Corpus Callosum Area Of Capuchin Monkeys, Kimberley A. Phillips, Chet C. Sherwood
Psychology Faculty Research
Capuchin monkeys (Cebus apella) are New World primates with relatively large brains for their body size. The developmental trajectories of several brain regions-including cortical white matter, frontal lobe white matter, and basal ganglia nuclei-are similar to humans. Additionally, capuchins have independently evolved several behavioral and anatomical characteristics in common with humans and chimpanzees-including complex manipulative abilities, use of tools, and the use of precision grips-making them interesting species for studies of comparative brain morphology and organization. Here, we report the first investigation into the development of the corpus callosum (CC) and its regional subdivisions in capuchins. CC development …