Whole-Brain Gray Matter Volume as an Anatomical Predisposition for Cognitive Ability
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The human brain is the topic of much interest in recent years, and due to the advent and rising popularity of imaging techniques such as functional MRI, we are able to understand the brain with greater detail than ever before. Cognitive ability has always been known to be heavily tied to neuroanatomy, and existing research has shown that although cognitive skill is heavily dependent on specific brain regions such as the dorsolateral prefrontal cortex or hippocampus it is a highly delocalized function that involves the use of numerous brain regions. Larger volumes of whole-brain gray matter has also been shown to be tied to greater success on cognitive assessments implying that volumetric estimations of gray matter can serve as an indication of cognitive ability. Brain volume varies between individuals for a variety of reasons such as sex, age, ethnicity, and socioeconomic status. The former three of these are well understood biological principles or processes, but the last of these is a societal effect on physiology and may include diet and nutrition, education and social development, or occupation and family life. This paper will also examine whole-brain gray matter volumes in respect to education. Subjects (n = 60) were imaged to collect T1-weighted fMRI structural scans and were given Memory Assessment Scales examinations afterwards. We performed voxel-based morphometry using DARTEL in Statistical Parametric Mapping on the fMRI structural scans to acquire the volumes of gray matter, white matter, and cerebrospinal fluid of each individual. These gray matter volumes were then related to the individual’s performance in a variety of cognitive domains tested for by the Memory Assessment Scales to examine if increasing gray matter volume has an effect on the individual’s performance. Years of education was also related to gray matter volume to observe if higher volumes correlated with higher education. Our findings suggest that gray matter does indeed demonstrate a small increase performance in some but not all cognitive domains tested for. The correlation with years of education pursued obtained was minimal, however it became slightly more pronounced in older individuals when the subjects were divided by age group. The brain volumes of the younger age group were determined to be statistically different from the older age group, but when these age groups were divided into high and low education classifications, the brain volumes from the two groups were not shown to be statistically different from each other. This indicates to us, that gray matter volume has a negligible effect on level of education pursued despite its seemingly positive effect on cognitive performance. It is important to understand that the mechanisms behind cognition are incredibly complex involving innumerable factors and that further exploration must begin at the biological level to expand our understanding of this phenomenon.