Parental experience, as well as changing hormone levels during pregnancy and postpartum, cause changes in the parental brain. Displaying maternal sensitivity towards infant cues, processing those cues and being motivated to engage socially with her infant and attend to the infant's needs in any context could be described as mothering behavior and is regulated by many systems in the maternal brain. Research has shown that hormones such as oxytocin, prolactin, estradiol and progesterone are essential for the onset and the maintenance of maternal behavior in rats, and other mammals as well. Mothering behavior has also been classified within the basic drives (sexual desire, hunger and thirst, fear, power/dominance etc.). Less is known about the paternal brain, but changes in the father's brain occur alongside the mother once the offspring is born.
- 1 Maternal brain
- 2 Paternal brain
- 3 References
Maternal hormonal effect
Different hormone levels in the maternal brain and the overall well being of the mother account for 40%–50% of differences in the mother's attachment to her infant. Mothers experience a decrease in estrogen and an increase in oxytocin and prolactin caused by lactation, pregnancy, parturition and interaction with the infant.
The levels of oxytocin in the maternal brain correlate with maternal behaviors such as gazing, vocalization, positive affect, affectionate touch and other similar mother-infant relationship behaviors.
Estradiol and progesterone
In the first few days after giving birth the levels of cortisol are high which correlates with maternal approach behavior and positive maternal attitudes. Mothers with high levels of cortisol were also found to be more vocal towards their children. Mothers who experienced adversity in their own childhood, had higher daily patterns of cortisol levels, and were less maternally sensitive.
Different areas/structures of the brain are associated with different factors which contribute to maternal behavior. One's own infant acts as a special stimulus which triggers activation of different areas of the brain. These brain areas together allow for maternal behavior and related systems.
The Medial Preoptic Area (MPOA) of the hypothalamus contains receptors for estradiol, progesterone, prolactin, oxytocin, vasopressin and opioids. All these hormones are involved in some way in activating maternal behavior in the brain. The following are other behavioral changes necessary for mothering that the MPOA is responsible for:
- mother's affect (changes made by the amygdala, prefrontal cortex)
- stimulus salience (changes made by the amygdala and nucleus accumbens)
- attention (changes made by the nucleus accumbens and medial prefrontal cortex)
- memory (changes made by the nucleus accumbens and medial prefrontal cortex).
The amygdala and medial prefrontal cortex also contain receptors for the hormones which are most likely to be changing behavior at the time of pregnancy, and may be the sites where these changes occur. Increased activity has also been observed in the amygdala as the mother is responding to emotions seen in negative (fearful) faces, positive faces or familiar faces that her baby makes. Primate mothers with damage to the prefrontal cortex have also been associated with disrupted maternal behavior.
The dorsolateral prefrontal cortex(DLPFC) plays a role in the attention, cognitive flexibility and working memory of the mother. It helps the mother identify infant cues. In any environment and efficiently, it allows for the decision-making and action planning process involved in attending to the infant's cues.
In animal mothers
Postpartum, new neuron production is suppressed due to decreased levels of estrogen and increased levels of glucocorticoids mother rats. Mother-infant interaction is also thought to suppress neurogenesis in the hippocampus postpartum in the rat maternal brain. Maternal experience increases neurogenesis in the subventricular zone (SBZ) which is responsible for producing the neurons of the olfactory bulb. Prolactin is the hormone which mediates the increase in neurogenesis in SBZ.
The volume of gray matter increases portpartum in the following brain regions:
These changes in the brain may occur in order to promote appropriate mothering behavior. The mother's positive attitude towards the infant can be used as a predictor for the increase in gray matter in the above stated brain structures.
Also in rats, the increased interaction with pups causes an increase in density in the MPOA. Postpartum increase in gray matter volumes may help the mother activate the motivation to perform maternal behavior in response to cue from their offspring.
In human mothers
Recent research has begun to look at how maternal psychopathology affects the maternal brain in relation to parenting. Daniel Schechter and colleagues have studied specifically interpersonal violence-related Post-traumatic Stress Disorder (PTSD)and comorbid dissociation as associated with specific patterns of maternal neural activation in response to viewing silent video-stimuli of stressful parent-toddler interactions such as separation versus less-stressful ones such as play. Importantly, less medial prefrontal cortex activity and greater limbic system activity (i.e. entorhinal cortex and hippocampus) were found among these post-traumatically stressed mothers of toddlers compared to mothers of toddlers without PTSD in response to stressful parent-child interactions as well as, within a different sample, in response to menacing adult male-female interactions. In the latter study, this pattern of corticolimbic dysregulation was linked to less observed maternal sensitivity during mother-child play.
Early experiences and shaping
Women who had a positive experience involving their family in their childhood are more likely to be more maternally sensitive and provide that same experience for their own children. Mothers that had negative experiences involving their families undergo neurobiological changes which lead to high stress reactivity and insecure attachment. This causes lower maternal responsiveness to their infant's needs.
Rat mothers provide high levels of maternal care (licking and grooming) to their offspring if they themselves received high maternal care as a pup from their own mothers. Rat mothers who received low levels of maternal care as pups have lower levels of expression of the glucocorticoid receptor gene and lower synaptic density in the hippocampus. In human mothers, lower hippocampal volume has been associated with a lower ability to regulate emotions and stress, which can be linked with decreased maternal sensitivity as a mother. Mothers with insecure attachments to their own mothers display higher amygdala sensitivity to negative emotional stimuli, like hearing their infant cry. Having more difficulty dealing with stress makes mothers less responsive to their infant's cues.
Larger gray matter and increased activations of the following brain areas occur in mothers who had experienced higher quality maternal care as infants:
This allows the mother to be more sensitive to her own infant's needs.
In only 6% of mammalian species, including humans, the father plays a significant role in caring for his young. Similar to the changes that occur in the maternal brain, the same areas of the brain (amygdala, hypothalamus, prefrontal cortex, olfactory bulb etc.) are activated in the father, and hormonal changes occur in the paternal brain to ensure display of parenting behavior.
Paternal hormonal effect
An increase in levels of oxytocin, glucocorticoids, estrogen and prolactin occur in the paternal brain. These hormonal changes occur through the father's interaction with the mother and his offspring. Oxytocin levels are positively correlated with the amount of affection the father displays towards the child. In humans, and in other primate species, lower levels of testosterone have been linked to the display of paternal behavior.
In animal fathers
In father rats, just as in the mother rats, a decrease in neurogenesis in the hippocampus occurs postpartum. Just like in mothers, fathers also have increased levels of glucocorticoids which are thought to suppress the production of new cells in the brain.
Marmoset fathers have enhanced dendritic spine density in the prefrontal cortex. This increase correlates with increase in vasopressin receptors in this area of the paternal brain. With age, this effect is reversed, and is therefore believed to be driven by father-infant interactions.
In human fathers
Being exposed to crying babies activates the prefrontal cortex and the amygdala in both fathers and mothers, but not in non-parents. The level of testosterone in the paternal brain correlates with the effectiveness of the dad's response to the baby's cry. Increased levels of prolactin in the paternal brain has also been correlated with a more positive response to the infant's cry.
- Leuner, B; Glasper, ER; Gould, E (Oct 2010). "Parenting and plasticity.". Trends in neurosciences 33 (10): 465–73. doi:10.1016/j.tins.2010.07.003. PMC 3076301. PMID 20832872.
- Barrett, Jennifer; Fleming, Alison S. (1 April 2011). "Annual Research Review: All mothers are not created equal: neural and psychobiological perspectives on mothering and the importance of individual differences". Journal of Child Psychology and Psychiatry 52 (4): 368–397. doi:10.1111/j.1469-7610.2010.02306.x.
- Bridges, R (2008). Neurobiology of the parental brain. Amsterdam: Academic.
- Bridges, R.S (1990). Endocrine regulation of parental behavior in rodents, Mammalian parenting: Biochemical, neurobiological and behavioral determinants. New York: Oxford University Press. pp. 93–117.
- Insel, T (1990). Oxytocin and maternal behavior, Mammalian parenting: biochemical, neurobiological and behavioral determinants. New York: Oxford University Press. pp. 260–280.
- Numan, M (Jan 2007). "Motivational systems and the neural circuitry of maternal behavior in the rat.". Developmental psychobiology 49 (1): 12–21. doi:10.1002/dev.20198. PMID 17186513.
- Pryce C.R, Martin RD, Skuse D (1995). Motherhood in human and nonhuman primates. New York: Karger.
- Rosenblatt, JS; Olufowobi, A; Siegel, HI (Apr 1998). "Effects of pregnancy hormones on maternal responsiveness, responsiveness to estrogen stimulation of maternal behavior, and the lordosis response to estrogen stimulation.". Hormones and behavior 33 (2): 104–14. doi:10.1006/hbeh.1998.1441. PMID 9647936.
- Sewards, TV; Sewards, MA (Aug 2002). "Fear and power-dominance drive motivation: neural representations and pathways mediating sensory and mnemonic inputs, and outputs to premotor structures.". Neuroscience and biobehavioral reviews 26 (5): 553–79. doi:10.1016/S0149-7634(02)00020-9. PMID 12367590.
- Fleming, AS; Ruble, D; Krieger, H; Wong, PY (Apr 1997). "Hormonal and experiential correlates of maternal responsiveness during pregnancy and the puerperium in human mothers.". Hormones and behavior 31 (2): 145–58. doi:10.1006/hbeh.1997.1376. PMID 9154435.
- Numan, M., Insel T. (2003). The Neurobiology of Parental Behavior. Springer-Verlag.
- Flemming, A.S; Steiner M and Andreson V (1987). "Hormonal and attitudinal correlates of maternal behavior during the early postparpregnancy". Journal of Reproductive and Infant Psychology 5: 193–205.
- Corter, C; Flemming A.S (1990). "Maternal responsiveness in humans: Emotional, cognitive and biological factors". Advances in the Study of Behavior 19: 83–136. doi:10.1016/s0065-3454(08)60201-6.
- Gonzalez, A; Jenkins, JM; Steiner, M; Fleming, AS (Jan 2009). "The relation between early life adversity, cortisol awakening response and diurnal salivary cortisol levels in postpartum women.". Psychoneuroendocrinology 34 (1): 76–86. doi:10.1016/j.psyneuen.2008.08.012. PMID 18835661.
- Leuner, B; Mirescu, C; Noiman, L; Gould, E (2007). "Maternal experience inhibits the production of immature neurons in the hippocampus during the postpartum period through elevations in adrenal steroids.". Hippocampus 17 (6): 434–42. doi:10.1002/hipo.20278. PMID 17397044.
- Rees, SL; Panesar, S; Steiner, M; Fleming, AS (Mar 2006). "The effects of adrenalectomy and corticosterone replacement on induction of maternal behavior in the virgin female rat.". Hormones and behavior 49 (3): 337–45. doi:10.1016/j.yhbeh.2005.08.012. PMID 16297919.
- Numan M, Fleming A.S, Levy F (2006). Maternal Behavior in Neill's physiology of reproduction. San Diego, CA: Elsevier. pp. 1921–1993.
- Matthiesen, AS; Ransjö-Arvidson AB; Nissen E; Uvnäs-Moberg K. (2001). "Postpartum maternal oxytocin release by newborns: effects of infant hand massage and sucking". PubMed; MEDLINE 28 (1): 13–9. doi:10.1046/j.1523-536x.2001.00013.x. PMID 11264623.
Newborns placed skin-to-skin with their mothers to study maternal oxytocin release.
- Gamer, M; Büchel, C (Jul 15, 2009). "Amygdala activation predicts gaze toward fearful eyes.". The Journal of neuroscience : the official journal of the Society for Neuroscience 29 (28): 9123–6. doi:10.1523/JNEUROSCI.1883-09.2009. PMID 19605649.
- Derntl, B; Habel, U; Windischberger, C; Robinson, S; Kryspin-Exner, I; Gur, RC; Moser, E (Aug 4, 2009). "General and specific responsiveness of the amygdala during explicit emotion recognition in females and males.". BMC neuroscience 10: 91. doi:10.1186/1471-2202-10-91. PMC 2728725. PMID 19653893.
- Killgore, WD; Yurgelun-Todd, DA (Apr 2004). "Activation of the amygdala and anterior cingulate during nonconscious processing of sad versus happy faces.". NeuroImage 21 (4): 1215–23. doi:10.1016/j.neuroimage.2003.12.033. PMID 15050549.
- Williams, MA; McGlone, F; Abbott, DF; Mattingley, JB (Jan 15, 2005). "Differential amygdala responses to happy and fearful facial expressions depend on selective attention.". NeuroImage 24 (2): 417–25. doi:10.1016/j.neuroimage.2004.08.017. PMID 15627583.
- Platek, SM; Kemp, SM (Feb 2009). "Is family special to the brain? An event-related fMRI study of familiar, familial, and self-face recognition.". Neuropsychologia 47 (3): 849–58. doi:10.1016/j.neuropsychologia.2008.12.027. PMID 19159636.
- Franzen, EA; Myers, RE (May 1973). "Neural control of social behavior: prefrontal and anterior temporal cortex.". Neuropsychologia 11 (2): 141–57. doi:10.1016/0028-3932(73)90002-x. PMID 4197348.
- Xerri, C; Stern, JM; Merzenich, MM (Mar 1994). "Alterations of the cortical representation of the rat ventrum induced by nursing behavior.". The Journal of neuroscience : the official journal of the Society for Neuroscience 14 (3 Pt 2): 1710–21. PMID 8126565.
- Rosenblatt, J.S (2002). Handbook of parenting. Mahwah, NJ: Erlbaum. pp. 31–60.
- Darnaudéry, M; Perez-Martin, M; Del Favero, F; Gomez-Roldan, C; Garcia-Segura, LM; Maccari, S (Aug 2007). "Early motherhood in rats is associated with a modification of hippocampal function.". Psychoneuroendocrinology 32 (7): 803–12. doi:10.1016/j.psyneuen.2007.05.012. PMID 17640823.
- Pawluski, JL; Galea, LA (Oct 12, 2007). "Reproductive experience alters hippocampal neurogenesis during the postpartum period in the dam.". Neuroscience 149 (1): 53–67. doi:10.1016/j.neuroscience.2007.07.031. PMID 17869008.
- Shingo, T; Gregg, C; Enwere, E; Fujikawa, H; Hassam, R; Geary, C; Cross, JC; Weiss, S (Jan 3, 2003). "Pregnancy-stimulated neurogenesis in the adult female forebrain mediated by prolactin.". Science 299 (5603): 117–20. doi:10.1126/science.1076647. PMID 12511652.
- Furuta, M; Bridges, RS (Apr 21, 2005). "Gestation-induced cell proliferation in the rat brain.". Brain research. Developmental brain research 156 (1): 61–6. doi:10.1016/j.devbrainres.2005.01.008. PMID 15862628.
- Kim, Pilyoung; Leckman, James F.; Mayes, Linda C.; Feldman, Ruth; Wang, Xin; Swain, James E. (1 January 2010). "The plasticity of human maternal brain: Longitudinal changes in brain anatomy during the early postpartum period.". Behavioral Neuroscience 124 (5): 695–700. doi:10.1037/a0020884.
- Featherstone, RE; Fleming, AS; Ivy, GO (Feb 2000). "Plasticity in the maternal circuit: effects of experience and partum condition on brain astrocyte number in female rats.". Behavioral neuroscience 114 (1): 158–72. doi:10.1037/0735-7044.114.1.158. PMID 10718271.
- McEwen, BS (Jul 2007). "Physiology and neurobiology of stress and adaptation: central role of the brain.". Physiological reviews 87 (3): 873–904. doi:10.1152/physrev.00041.2006. PMID 17615391.
- Bartels, A; Zeki, S (Mar 2004). "The neural correlates of maternal and romantic love.". NeuroImage 21 (3): 1155–66. doi:10.1016/j.neuroimage.2003.11.003. PMID 15006682.
- Noriuchi, M; Kikuchi, Y; Senoo, A (Feb 15, 2008). "The functional neuroanatomy of maternal love: mother's response to infant's attachment behaviors.". Biological Psychiatry 63 (4): 415–23. doi:10.1016/j.biopsych.2007.05.018. PMID 17686467.
- Protopopescu, X; Butler, T; Pan, H; Root, J; Altemus, M; Polanecsky, M; McEwen, B; Silbersweig, D; Stern, E (2008). "Hippocampal structural changes across the menstrual cycle.". Hippocampus 18 (10): 985–8. doi:10.1002/hipo.20468. PMID 18767068.
- Castro-Fornieles, J; Bargalló, N; Lázaro, L; Andrés, S; Falcon, C; Plana, MT; Junqué, C (Jan 2009). "A cross-sectional and follow-up voxel-based morphometric MRI study in adolescent anorexia nervosa.". Journal of Psychiatric Research 43 (3): 331–40. doi:10.1016/j.jpsychires.2008.03.013. PMID 18486147.
- Raji, CA; Ho, AJ; Parikshak, NN; Becker, JT; Lopez, OL; Kuller, LH; Hua, X; Leow, AD; Toga, AW; Thompson, PM (Mar 2010). "Brain structure and obesity.". Human brain mapping 31 (3): 353–64. doi:10.1002/hbm.20870. PMC 2826530. PMID 19662657.
- Schechter DS, Moser D, Wang Z, Marsh R, Hao XJ, Duan Y, Yu S, Gunter B, Murphy D, McCaw J, Kangarlu A, Willheim E, Myers M, Hofer M, Peterson BS (2012 epub 22.10.11). An fMRI study of the brain responses of traumatized mothers to viewing their toddlers during separation and play. Journal of Social, Cognitive and Affective Neuroscience, 7(8), 969-79. doi: 10.1093/scan/nsr069. Epub 2011 Oct 22.
- Moser DA, Aue T, Wang Z, Rusconi-Serpa S, Favez N., Peterson BS, Schechter DS (2014). Comorbid dissociation dampens limbic activation in violence-exposed mothers with PTSD who are exposed to video-clips of their child during separation. Stress. 16(5):493-50. doi: 10.3109/10253890.2013.816280. Epub 2013 Jul 23.
- Moser DA, Aue T, Favez N, Kutlikova H, Suardi F, Cordero MI, Rusconi Serpa S, Schechter DS. (2014 epub July 25). Violence-related PTSD and neural activation when seeing emotional male-female interactions. Social, Cognitive, and Affective Neuroscience.
- Belsky, J; Jaffee, SR; Sligo, J; Woodward, L; Silva, PA (Mar–Apr 2005). "Intergenerational transmission of warm-sensitive-stimulating parenting: a prospective study of mothers and fathers of 3-year-olds.". Child Development 76 (2): 384–96. doi:10.1111/j.1467-8624.2005.00852.x. PMID 15784089.
- Belsky, J (2005). The developmental and evolutionary psychology of intergenerational transmission of attachment in Attachment and bonding: A new synthesis. Cambridge, MA: MIT Press. pp. 169–198.
- Meaney, MJ (2001). "Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations.". Annual review of neuroscience 24: 1161–92. doi:10.1146/annurev.neuro.24.1.1161. PMID 11520931.
- Francis, D; Diorio, J; Liu, D; Meaney, MJ (Nov 5, 1999). "Nongenomic transmission across generations of maternal behavior and stress responses in the rat.". Science 286 (5442): 1155–8. doi:10.1126/science.286.5442.1155. PMID 10550053.
- Francis, DD; Young, LJ; Meaney, MJ; Insel, TR (May 2002). "Naturally occurring differences in maternal care are associated with the expression of oxytocin and vasopressin (V1a) receptors: gender differences.". Journal of neuroendocrinology 14 (5): 349–53. doi:10.1046/j.0007-1331.2002.00776.x. PMID 12000539.
- Kaffman, A; Meaney, MJ (Mar–Apr 2007). "Neurodevelopmental sequelae of postnatal maternal care in rodents: clinical and research implications of molecular insights.". Journal of child psychology and psychiatry, and allied disciplines 48 (3–4): 224–44. doi:10.1111/j.1469-7610.2007.01730.x. PMID 17355397.
- Bredy, TW; Grant, RJ; Champagne, DL; Meaney, MJ (Nov 2003). "Maternal care influences neuronal survival in the hippocampus of the rat.". The European Journal of Neuroscience 18 (10): 2903–9. doi:10.1111/j.1460-9568.2003.02965.x. PMID 14656341.
- Heim, C; Nemeroff, CB (Jan 2009). "Neurobiology of posttraumatic stress disorder.". CNS spectrums 14 (1 Suppl 1): 13–24. PMID 19169190.
- Lemche, E; Giampietro, VP; Surguladze, SA; Amaro, EJ; Andrew, CM; Williams, SC; Brammer, MJ; Lawrence, N; Maier, MA; Russell, TA; Simmons, A; Ecker, C; Joraschky, P; Phillips, ML (Aug 2006). "Human attachment security is mediated by the amygdala: evidence from combined fMRI and psychophysiological measures.". Human brain mapping 27 (8): 623–35. doi:10.1002/hbm.20206. PMID 16284946.
- Martorell, GA; Bugental, DB (Dec 2006). "Maternal variations in stress reactivity: implications for harsh parenting practices with very young children.". Journal of family psychology : JFP : journal of the Division of Family Psychology of the American Psychological Association (Division 43) 20 (4): 641–7. doi:10.1037/0893-318.104.22.1681. PMID 17176199.
- Kim, Pilyoung; Leckman, James F.; Mayes, Linda C.; Newman, Michal-Ann; Feldman, Ruth; Swain, James E. (30 September 2009). "Perceived quality of maternal care in childhood and structure and function of mothers' brain". Developmental Science 13 (4): 662–673. doi:10.1111/j.1467-7687.2009.00923.x. PMID 20590729.
- Mayes, L.C; Leckman, J.F (2007). "Parental representation and subclinical changes in postpartum mood". Infant Mental Health Journal 28: 281–295. doi:10.1002/imhj.20136.
- Lonstein, JS; De Vries, GJ (Aug 2000). "Sex differences in the parental behavior of rodents.". Neuroscience and biobehavioral reviews 24 (6): 669–86. doi:10.1016/S0149-7634(00)00036-1. PMID 10940441.
- Fernandez-Duque, E et al. (2009). "The biology of paternal care in human and non-human primates". Annu. Rev. Anthropol 38: 115–130. doi:10.1146/annurev-anthro-091908-164334.
- Wynne-Edwards, KE (Sep 2001). "Hormonal changes in mammalian fathers.". Hormones and behavior 40 (2): 139–45. doi:10.1006/hbeh.2001.1699. PMID 11534974.
- Feldman, R; Gordon, I; Schneiderman, I; Weisman, O; Zagoory-Sharon, O (Sep 2010). "Natural variations in maternal and paternal care are associated with systematic changes in oxytocin following parent-infant contact.". Psychoneuroendocrinology 35 (8): 1133–41. doi:10.1016/j.psyneuen.2010.01.013. PMID 20153585.
- Fleming, AS; Corter, C; Stallings, J; Steiner, M (Dec 2002). "Testosterone and prolactin are associated with emotional responses to infant cries in new fathers.". Hormones and behavior 42 (4): 399–413. doi:10.1006/hbeh.2002.1840. PMID 12488107.
- Kozorovitskiy, Y et al. (2007). "Fatherhood influences neurogenesis in the hippocampus of California mice". Society for Neuroscience 21: 626.
- Kozorovitskiy, Y; Hughes, M; Lee, K; Gould, E (Sep 2006). "Fatherhood affects dendritic spines and vasopressin V1a receptors in the primate prefrontal cortex.". Nature Neuroscience 9 (9): 1094–5. doi:10.1038/nn1753. PMID 16921371.
- Mak, GK; Weiss, S (Jun 2010). "Paternal recognition of adult offspring mediated by newly generated CNS neurons.". Nature Neuroscience 13 (6): 753–8. doi:10.1038/nn.2550. PMID 20453850.
- Seifritz, E; Esposito, F; Neuhoff, JG; Lüthi, A; Mustovic, H; Dammann, G; von Bardeleben, U; Radue, EW; Cirillo, S; Tedeschi, G; Di Salle, F (Dec 15, 2003). "Differential sex-independent amygdala response to infant crying and laughing in parents versus nonparents.". Biological Psychiatry 54 (12): 1367–75. doi:10.1016/s0006-3223(03)00697-8. PMID 14675800.
- Swain, JE; Lorberbaum, JP; Kose, S; Strathearn, L (Mar–Apr 2007). "Brain basis of early parent-infant interactions: psychology, physiology, and in vivo functional neuroimaging studies.". Journal of child psychology and psychiatry, and allied disciplines 48 (3–4): 262–87. doi:10.1111/j.1469-7610.2007.01731.x. PMID 17355399.