Plasticity and Structural Changes in the Maternal Brain

During pregnancy, a woman’s brain undergoes both structural and hormonal changes in preparation for the task of motherhood. These changes are reflected in the expression of maternal behaviours following the birth of the child. These behaviours are essential to the neurological and psychosocial development of the offspring. Recent studies have indicated changes to the cortical and subcortical regions associated with emotional responsivity.[1] Furthermore, elevated levels of estrogen, progesterone, and glucocorticoids during pregnancy have been implicated in neurogenesis within both cortical and subcortical structures associated with maternal behaviour.[1] When atypical, these changes in the brain can lead to post-partum depression in the mother which negatively affect her ability to foster her child's development1. Changes in the maternal brain are accompanied by changes in the fetal brain which undergo epigenetic alterations due to both maternal and paternal influences, and various environmental factors.[2] Together, these illustrate an underlying physiological mechanism of a tripartite relationship consisting of father, mother, and infant, which lays the crucial foundation for the rest of the infant’s life.

1. Brunton PJ, Russel JA. The expectant brain: adapting for motherhood. Nat Rev Neurosci. (2008) 9:11-25.
2. Perera F, Herbstman J. Prenatal environmental exposures, epigenetics, and disease. Reprod Toxicol. (2011) 31(3):363-373.

Changes in Maternal Behaviour in Response to Hormonal Regulation

main article: Changes in Maternal Behaviour in Response to Hormonal Regulation
author: Patrick Ng

Maternal Behaviour
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Dam nursing pup offspring. Source: Rogers, 2013

During pregnancy, the maternal brain undergoes significant changes as a result of hormonal regulation. In response to these changes postpartum, behavioural manifestations of said regulation are produced and are shown to have even further effects in offspring [1][Bibliography item 5 not found.][3][4]. Studies in animal/human relationship models between mothers and offspring help deepen our understanding of behaviour versus brain plasticity.

1. Bartz, J. A., Zaki, J., Ochsner, K. N., Bolger, N., Kolevzon, A., Ludwig, N., et al. (2010). Effects of oxytocin on recollections of maternal care and closeness. Proceedings of the National Academy of Sciences, 107(50), 21371-21375.
2. Bosch, O. J., & Neumann, I. D. (2010). Vasopressin released within the central amygdala promotes maternal aggression. European Journal of Neuroscience, 31(5), 883-891.
3. Lukas, M., Bredewold, R., Neumann, I., & Veenema, A. (2010). Maternal separation interferes with developmental changes in brain vasopressin and oxytocin receptor binding in male rats. Neuropharmacology, 58(1), 78-87.
4. Veenema, A. H., & Neumann, I. D. (2009). Maternal separation enhances offensive play-fighting, basal corticosterone and hypothalamic vasopressin mRNA expression in juvenile male rats. Psychoneuroendocrinology, 34(3), 463-467.

Hormonal Influences

main article: Hormonal Influences
author: Harps
The female mammalian brain undergoes a variety of changes during pregnancy which allow for maintenance of the pregnancy, healthy fetal development, parturition, and most importantly, maternal behaviours[1]. Hormonal changes are also prevalent during pregnancy[1]; hence, it is beneficial to understand how hormonal fluctuations and structural changes in the maternal brain are linked. The existing literature suggests that various hormones can have both positive and negative effects on the brain during pregnancy, some of which can persist post-parturition[1]. Since the changes that take place are not restricted to regions of the brain associated with maternal behaviour (i.e. the cingulate cortex[2]), rather extending to regions involved in learning and memory as well[3], understanding how hormones cause these often long-lasting changes to the female brain is essential for preventative and treatment purposes, especially since pregnancy is experienced by such a large portion of the world's female population.

1. Workman, J.L. et al. Endocrine substrates of cognitive and affective changes during pregnancy and postpartum. Behav Neurosci. 126, 54-72 (2012).
2. Salmaso, N., Nadeau, J., and Woodside, B. Steroid hormones and maternal experience interact to induce glial plasticity in the cingulate cortex. Behav Neurosci. 29, 786-794 (2009).
3. Glynn, L.M. Giving birth to a new brain: Hormone exposure of pregnancy influence human memory. Psychoneuroendocrino. 35, 1148-1155 (2010).

Paternal Influences on Fetal Epigenome and Neurodevelopment: An Epigenetic Perspective

main article: Paternal Influences on Fetal Epigenome and Neurodevelopment: An Epigenetic Perspective
author: You Oh
Epigenetics is the study of heritable changes in gene activity or phenotype that are not caused by changes in the DNA sequence.[1] Environmental epigenomics reveals the intricate communication between the epigenome and environment, including both exogenous (such as nutritional and chemical exposures) and endogenous (such as immune status and levels of hormones) factors.[2] It has been well established that various factors such as stress and nutrition during pregnancy can influence fetal development. Furthermore, it was recently shown that paternal experiences can also be transmitted through neuroepigenetic marks.[3] The greatest advantage in studying paternal influence on the fetal epigenome is that complex confounding factors such as maternal behaviours and variability in the intrauterine environment can be excluded. Paternal experiences and exposure to diverse environmental conditions alter the fetal epigenome, affecting subsequent neurodevelopment of the offspring and possibly leading to disorders and disease that manifest in childhood or later on in the course of the offspring’s life.

Fetal Neurodevelopment
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Harryman, W. Integral Options Cafe. Retrieved from
1. Bollati V, Baccarelli A. Environmental epigenetics. Heredity. 205, 105–12 [PubMed:
20179736] (2010).
2. Perera F, Herbstman J. Prenatal environmental exposures, epigenetics, and disease. Reprod Toxicol. 31(3), 363-373 (2011).
3. Champagne, F. Epigenetic mechanisms and the transgenerational effects of maternal care. Frontiers in neuroendocrinology 29, 386–97 (2008).

Post-Partum Depression

main article: Post-Partum Depression
author: Sabina Freiman


Around one in seven women each year will develop post-partum depression (PPD), which is defined as a major depressive episode just following childbirth.[1] The DSM-IV requires the episode to occur within four weeks, but it has been shown to occur within the first three months.[2] As described in Baker et al, symptoms include sadness, frequent crying, lack of motivation, low interest in food of self-care, difficulty concentrating and low interest in the new baby.[3] While we do not know what exactly causes a woman to develop PPD, there have been several correlates found in those who go on to develop it, ranging from the food she eats, to her genes, to how she feels during pregnancy. Mothers are prepared for the journey of motherhood after being rewired during pregnancy: what is it about the post-partum mother that makes her so different? Studies have shown differences in brain activation patterns and levels of certain factors that distinguish post-partum mothers from their counterparts. It is crucial to understand PPD, and how to treat it, because of its effects on maternal behaviour, which has great influence on infant development. Mothers with PPD show suboptimal bonding behaviour, which leads to dysregulated infant behaviour and delays in social and cognitive development in the infant.[4] Understanding PPD highlights the importance of plasticity within the brains of mothers and babies alike.

Symptoms of PPD
1. Gaynes BN, United States. Agency for Healthcare Research and Quality, Research Triangle Institute-University of North Carolina Evidence-based Practice Center. Perinatal Depression: Prevalence, Screening Accuracy, and Screening Outcomes. Evidence Report/Technology Assessment No. 119 (2005).
2. Fitelson E, Kim S, Baker AS, Leight K. Treatment of postpartum depression: clinical, psychological and pharmacological options. International Journal of Women’s Health (2011) 3:1-14.
3. Baker, L, et al. Prevalence of Postpartum Depression in a Native American Population. Matern Child Healt J (2005). 9(1):21-25.
4. Conroy, S., et al. Maternal Psychopathology and Infant Development at 18 Months: The Impact of Maternal Personality Disorder and Depression. J Am Acad Child Psy. (2012) 51(1):51-61.

Structural changes in the maternal brain following birth

main article: Structural changes in the maternal brain following birth
author: Kareem Jarrah

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Maternal Love by Lisa Marsman [4]

The maternal brain undergoes various structural changes after birth to ensure the female brain is suitably primed and developed into a maternal brain. These adaptive changes ensure the mother is suitably prepared to raise her offspring [1]. Neural changes occur to illicit a stronger face recognition response from the mother when viewing her child [1]. Neural rewiring also induces a strong maternal attachment to the offspring mediated through the brain’s reward pathways and related structures, specifically the substantia nigra [2]. Following the post-partum period, as offspring age, the maternal brain remains adaptive and dynamic rewiring itself to the diminishing needs of the offspring. As mothering is a social behavior, a mother’s ability to raise her offspring can be impaired following physical trauma to the prefrontal cortex or following psychological trauma inducing long-lasting changes in prefrontal cortex [3]. These cortical and subcortical structures help shape the maternal brain, and thus behavior, to ensure the mother is well prepared to raise her offspring.

1. Noriuchi, M., Kikuchi Y., Senoo A. The Functional Neuroanatomy of Maternal Love: Mother’s Response to Infant’s Attachment Behaviors. Biol Psychiatry. 2008; 63: 415–423
2. Numan, M., Rosenblatt, J.S., Komisaruk, B.R. Medial preoptic area and onset of maternal behavior in the rat. J Comp Phys Psyc. 1977; 91(1): 146-164
3. Barrett, J., Fleming, A.S. Annual Research Review: All mothers are not created equal: neural and psychobiological perspectives on mothering and the importance of individual differences. J Child Psyc & Psychiatry. 2011; 52(4): 368–397

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