Genetics of Brain and Cognitive Aging and its Review

Short Communication - Neurophysiology Research (2021) Volume 3, Issue 2

Ever since Sir Francis Galton expounded on the role of heredity in human variation, from mental abilities

to physical characteristics, psychologists, biologists, and geneticists have pursued scholarly exploration

into the role of nature and nurture for human traits. Some traits that are more somatically defined, such

as morphological characteristics (height) were assumed to be more heritable than other traits, such as

human behavior, for which the role of genetic influences has at times been fiercely debated. During the

last 35 years, there has been a growing appreciation that genetic variation is relevant for understanding

individual differences in human traits, from morphological characteristics to behavioral traits. Indeed,

the focus has moved from quantifying the relative contribution of genetic influences, i.e. estimating

heritability, to identifying which genes are involved in pathways that impinge on human traits in order

to understand the genetic architecture. This issue of Neuropsychology Review is a timely sequel to the

previous special issues on Aging and Dementia and on Development of Human Brain Structure and

Function. The papers in the current issue review the role of genes on the full range of brain development,

morphology and function from childhood through late life, human communication, cognitive abilities, and

dementia. The current issue of the journal touches on a variety of methodologies available to understand

the genetics of brain and cognitive aging. The utility of comparative genomics for understanding the

“ancient genetic foundations” of human communicative abilities is elucidated by Graham, Derizoitis,

and Fisher. Moving beyond an evolutionary perspective, they also describe a number of other strategies

that have been fruitful for understanding genetic factors in communicative abilities, such as taking a

developmental perspective and studying developmental communication disorders and linkage studies to

identify specific candidate genes followed by karyotyping to identify chromosomal aberrations in rare

disorders. As in several of the other reviews in this issue, they also describe the utility of twin studies

for evaluating heritability, endophenotypes through neuroimaging, experimental paradigms and animal

models to understand the function of specific genes, and the role of genome wide association studies

(GWAS). The following three reviews—by Jansen et al, Papenberg et al., and Strike et al.— all have

in common a focus on genetics of brain structure and function. Jansen et al. summarize what twin

studies tell about the heritability of brain development, morphology and function, contrasting findings

from children, adults and the elderly. Heritabilities of brain structure are generally substantial, and

crosssectional comparisons suggest slight increases from childhood to adulthood. Longitudinal studies

are needed to understand better the heritability of changes in measurements of structure or function

Author(s): Asma Ibrahim,