Mums and dads over 70 have thicker grey matter in their brains than people who had never had kids, scientists report.
Australian researchers used magnetic resonance imaging to examine differences in grey matter thickness related to parenthood in late life, for both sexes.
Grey matter is mostly found on outer-most layer of the brain, or cortex, and serves to process information.
Both mums and dads over 70 had thicker grey matter brain regions than people who had never had kids, they found.
Generally, the thickness of the brain’s grey matter declines with age, meaning being a parent may help keep the brain young.
The Aussie research team claim to be the first to reveal parenthood-related brain differences in late-life.
Women who have had more kids tend to have better memory function later in life, according to Australian research, which also found that both mums and dads over 70 had thicker cortical brain regions than people who had never had kids
‘This study is the first examination of the relationship between parenthood and the ageing human brain,’ the research team write in PLOS ONE.
‘This study provides preliminary evidence to suggest that neural changes associated with early stages of parenthood persist into older age, and for women, may be related to marginally better cognitive outcomes.
‘The neuroscience of parenthood is an important area for further research to identify the critical time periods of parenthood when the brain is highly plastic, and examine longitudinal changes beyond the immediate post-partum months.’
New parents face an endless series of novel challenges to ensure the survival of their offspring, the study authors say.
‘In addition to their own personal needs and existing responsibilities, new parents must confront persistent demands for care and protection of their infant.
Grey matter is mostly found on outer-most layer of the brain, or cortex, and serves to process information
‘As children grow, new challenges arise – nappies and baby bottles are swapped for school lunches and soccer practice.’
Pregnancy and the early postpartum period alter the structure of the brain, particularly in regions related to parental care, to help adapt to the arrival of a child.
However, the lasting impact of parenthood on human brain structure and cognition is unknown and research in this field still in its infancy.
To learn more, the researchers at Monash University in Melbourne sampled brain scan data of 287 males and 260 females aged between aged 70 to 88.
Participants also completed a short cognitive task and were asked how many children they produced.
In 235 healthy older women, the research team found find a positive relationship between parity (number of children parented) and memory performance in mothers.
Brain regions showing a significant relationship between cortical thickness and number of children for female. Regions highlighted in red (right parahippocampal gyrus) depict a positive relationship, regions highlighted in blue (left pericalcarine sulcus and cuneus) depict a negative relationship
For mothers, three regions of the brain showed a significant relationship with number of children.
Cortical thickness in the left pericalcarine sulcus, left cuneus and right precuneus decreased as the number of children parented increased.
In males, however, fathers showed thinner grey matter in the left anterior cingulate cortex and thicker grey matter in the right temporal pole, compared with childless men.
As expected, the results were smaller in males than in females, possibly due to ‘differences in care-giving responsibilities between the sexes’ and the greater biological involvement of the mother historically.
‘The cohort examined in this study most likely included participants who were predominantly in “traditional” care-giving arrangements, with roles and responsibilities as primary care-giving mothers and “bread-winning” fathers,’ they say.
The team also compared non-parents to parents of one child, in a sub-sample of 45 older women and 35 older men.
For females, six brain regions differed in cortical thickness between parents and non-parents, and these regions were consistent with those seen earlier in life in previous studies.
While for males, five brain regions differed in cortical thickness between parents and non-parents.
The team say their results are consistent with previously identified areas that are altered during pregnancy and the postpartum period.
‘We argue that these late-life structural brain differences associated with parenthood are related to the environmental complexity of parenthood,’ they say.
The mere presence of offspring is sufficient to produce neural changes associated with parenting, they suggest.
However, this type of study cannot show that having kids actually caused the improvements in brain function that the researchers observed.
The social structure of this generation that participated in the study may also have limited the results.
WHAT IS A MAGNETIC RESONANCE IMAGING (MRI) SCAN?
Magnetic resonance imaging (MRI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body.
An MRI scanner is a large tube that contains powerful magnets. You lie inside the tube during the scan.
An MRI scan can be used to examine almost any part of the body, including the brain and spinal cord, bones and joints, breasts, heart and blood vessels and internal organs – such as the liver, womb or prostate gland.
Magnetic resonance imaging (MRI) is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body. An MRI scanner is a large tube that contains powerful magnets. You lie inside the tube during the scan
The results of an MRI scan can be used to help diagnose conditions, plan treatments and assess how effective previous treatment has been.
Most of the human body is made up of water molecules, which consist of hydrogen and oxygen atoms. At the centre of each hydrogen atom is an even smaller particle, called a proton. Protons are like tiny magnets and are very sensitive to magnetic fields.
When you lie under the powerful scanner magnets, the protons in your body line up in the same direction, in the same way that a magnet can pull the needle of a compass.
Short bursts of radio waves are then sent to certain areas of the body, knocking the protons out of alignment. When the radio waves are turned off, the protons realign. This sends out radio signals, which are picked up by receivers.
These signals provide information about the exact location of the protons in the body. They also help to distinguish between the various types of tissue in the body, because the protons in different types of tissue realign at different speeds and produce distinct signals.
In the same way that millions of pixels on a computer screen can create complex pictures, the signals from the millions of protons in the body are combined to create a detailed image of the inside of the body.