Poster No:
1796
Submission Type:
Late-Breaking Abstract Submission
Authors:
Caitlin Dale1, Florian Kurth2, Eileen Luders3
Institutions:
1The University of Auckland, Auckland, Auckland, 2University of Jena, Jena, Germany, 3The University of Auckland, Auckland, New Zealand
First Author:
Co-Author(s):
Late Breaking Reviewer(s):
Ruby Kong
Computational Brain Imaging Group, Yong Loo Lin School of Medicine, National University of Singapor
Singapore, Singapore
Introduction:
Although the corpus callosum is larger in larger brains in an absolute sense, it is suggested to display a proportional reduction as brain size increases. This is thought to occur as larger brains are subject to greater conduction pressures, which drives increasing lateralisation. Consequently, larger brains may rely more on local intra-hemispheric connections rather than the long-range inter-hemispheric connections enabled by the corpus callosum. That said, there are a lack of well-powered studies with large sample sizes to provide robust evidence for this effect.
Methods:
Here we utilised structural T1-weighted MRI data for a sample of 44,067 participants (23,372 women; 20,695 men) derived from the UK Biobank, aged between 45 and 84 years (mean ± SD: 64 ± 7.74 years). Proportional callosal volume was determined as the ratio of total callosal volume to total intracranial volume (TIV), which was used as a proxy for brain size. A linear model was fitted using proportional callosal volume as the dependent variable, TIV as the independent variable, and sex, age and handedness as possible moderating variables.
Results:
There was a significant main effect of TIV (p<0.0001), with larger relative corpora callosa in smaller brains. There were no significant interactions between TIV and sex, age, or handedness. However, there were significant main effects of sex and age (p<0.0001), with larger relative corpora callosa in females than in males and in young than in old. In contrast, there was no significant main effect of handedness.
Conclusions:
Our findings seem to indicate that larger brains exhibit relatively reduced inter-hemispheric connectivity compared to smaller brains, which might support the assumption of enhanced local intra-hemispheric connections as brain size increases. However, given that we only analysed callosal volume (as a proxy for inter-hemispheric connectivity), further research is needed. For example, follow-up studies might want to consider additionally analysing intra-hemispheric connections as well as obtaining measures of fibre integrity (e.g., fractional anisotropy). Similarly, future studies might benefit further from complementing structural measures with actual functional or behavioral measures.
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
White Matter Anatomy, Fiber Pathways and Connectivity 1
Novel Imaging Acquisition Methods:
Anatomical MRI 2
Keywords:
Hemispheric Specialization
STRUCTURAL MRI
White Matter
1|2Indicates the priority used for review
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Was this research conducted in the United States?
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Structural MRI
For human MRI, what field strength scanner do you use?
3.0T
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Free Surfer
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