5/28- Neurobiology of Attachment Flashcards
Molecular mechanisms underlying maternal attachment?
- Dopamine and reward processing
- Oxytocin and social affiliation
In what region is DA involved in reward processing?
When is it released?
Responsible for development of what?
- Ventral striatum
- Important in rat maternal behavior; released during mother-pup interaction
- Important factor in cognitive development and establishing reward-based contingencies
In what region is oxytocin involved?
Responsible for development of what?
- Peripheral and central brain
- Critical for the social and maternal behavior; MATERNAL CAREGIVING (critical for initiation of maternal care)–rats
- In ewes, oxytocin results in selective bonding with lamb
- Social memory (rats sniffing around new rats less upon 2nd introduction; when oxytocin blocked, demonstrated introductory behavior each time)
- Anxiolytic properties
Result of interplay in oxytocin/dopamine systems?
- Oxytocin neurons may also connect with the brain’s dopamine “reward” system, resulting in changes in “long-term conditioned preferences”
- Basically, oxytocin starts things and dopamine promotes its continuation
What is attachment?
- Innate biological system to ensure protection and reproduction
- Even kids exposed to poor quality care develop attachment (although particular behavior/type of attachment differs based on quality of caregiving)
- Individual differences in attachment “security” are associated with maternal care and infant social/emotional development
- (Attachment theory originally formulated by John Browlby in 1969)
What is a typical baby’s response to a predictable pattern of decreased maternal attention/neglect?
- Initially cries more
- Eventually cries much less; passive baby
What is a typical baby’s response to an unpredictable pattern of decreased maternal attention/neglect?
(e. g. working multiple jobs, domestic abuse)
- Constantly irritable child (b/c sometimes crying elicits a response)
Model of maternal brain responses: what neuroendocrine pathways are involved in the development of maternal caregiving behavior?
Dopamine:
- Mesocorticolimbic pathway (reward)
- Nigrostriatal pathway (action contingencies- you feel the reward now what do you do about it)
What are the three levels of neurodevelopment in these paths?
- Forebrain- “frontal cortex”- cognitive, analytical processing
- Limbic brain- “striatum”- emotion processing
- Midbrain- “meso/nigro”
What are 3 level components of the mesocorticolimbic dopamine pathway?
“Reward”:
- Medial prefrontal cortex (mPFC)
- Ventral striatum
- Ventral tegmental area (VTA)
What are 3 level components of the nigrostriatal dopamine pathway?
“Action Contingencies”
- Dorsolateral prefrontal cortex (DLPFC)
- Dorsal striatum
- Substantia nigra (SN)
Where/at what level does the oxytocin pathway feed in?
Into the mesocorticolimbic pathway via the hypothalamus
- Ventral striatum
- Ventral tegmental area
What else feeds into the substantia nigra (Nigrostriatal Path)?
Ventral striatum
(So both ventral and dorsal striatums)
Study examining these neuroendocrine pathways in human mothers?
- Visit 1: pregnancy (1st time pregnant women enrolled during 3rd TM and surveyed for own pattern of attachment)
- Visit 2: videotaping (about 7 mo, studies and peripheral blood hormone levels at separated baseline, with mother interaction, and separation again)
- Visit 3: scanning (fMRI responses to pictures of baby and stranger’s baby: happy, sad, neutral) - Visit 4: follow up (measuring infant attachment with strange procedure)
What does fMRI map?
Functional Magnetic Resonance Imaging
- Allows for time course of human brain activity to be imaged (as indicated by blood flow to that area)
- Stimulus -> neural pathway -> hemodynamics
What was the pattern of response for own vs. stranger’s smiling baby?
Dorsal striatum (nigrostriatal)
- significant rise in signal for own vs. unknown baby’s smiling face
What is the significance of a child with secure or insecure/dismissing mothers?
Measure of someone’s adaptiveness to their environment; secure and insecure not necessarily “good” and “bad”
(each is good for that baby’s unique environment; although not always adaptive in adulthood/long term)
Group comparisons between secure and insecure/dismissing mothers
Secure
- Increased breastfeeding duration (NS trend)
- Less mother-infant separation at 6 mo
No significant group differences with respect to:
- Maternal SES, race, education, or IQ
- Self-reported parenting stress
- Pre or post-natal depression or pscyhopathology risk
- Mother or infant temperament
- Infant development at 14 mo
Brain responses to smiling faces in secure vs. insecure/dismissing mothers?
Secure: activated many reward circuits (mesocorticolimbic path)
- Medial PFC
- Orbitofrontal cortex
- Ventral striatum
Insecure/dismissing: activated more nigrostriatal path
- Dorsolateral PFC
Brain responses to sad faces in secure vs. insecure/dismissing mothers?
Secure: still reward-based response (mesocorticolimbic path)
- Ventral striatum
Insecure/dismissing: activated more nigrostriatal path
- Dorsolateral PFC
- Anterior insula (also activated in response to physical/emotional pain and disgust)— seeing own baby in distress activates distress in themselves (decreased ability to respond to and soothe)
Change in peripheral oxytocin with mother-infant interaction with secure vs. insecure mothers?
(Baseline -> free play -> mirror interaction -> baseline post)
Increase in oxytocin during engagement with baby for secure vs. insecure mothers
Oxytocin levels corresponded to activity of what in the brain?
- Hypothalamus/pituitary region activity
- Ventral striatum activation (again showing interplay between oxytocin and DA systems)
Modified still-face and instant affect experiment phases?
- Phase 1: normal interaction (can see but not interact)
- Phase 2: still-face; completely emotionless, but eye contact
- Phase 3: recovery (observing baby’s adaptation back to normal)
What is the infants affect during these different phases of the still-face experiment?
- Negative affect: big rise during still-face, and not really recovering afterward
- Positive affect: big drop during still-face with some bounce back during recovery
What is the biggest marker of attachment pattern (secure vs. insecure mothers) in the recovery phase of the still-face experiment?
The mother expressing thoughts about the baby’s feelings/what was going on in the baby’s mind; mom’s ability to vocalize to indicated understanding of baby’s feelings/thoughts (e.g. Wasn’t that strange? What do you think about that?)
Sidenote: most secure mother babies remained looking at mom while insecure would look at themselves in the mirror
What were the difference between attachment and mirroring (direct facial/gestural, vocal, and intention) for secure vs. insecure mothers during the still-face experiment?
- Facial/gestural mirroring: no difference for any of the three phases
- Vocal mirroring: no difference for any of the three phases
- Intention mirroring: BIG significant difference for the three phases (much more for secure mothers)
Classifying by this intention mirroring response correlated 73% with INFANT class (results of strange situation)
How strongly do mother and infant attachment patterns correlate?
73% match
- 65% of secure mothers have secure infants
- 71% of insecure mothers have insecure infants
Mothers with secure attachment demonstrated what hormonal/behavioral responses and to what stimuli?
- Increased DA reward responses in the brain on seeing their infant’s face
- Increased oxytocin response on interacting with their infant
- More attuned vocal communication with their infant
- More likely to have children with “secure” attachment
(There is also intergenerational transmission of mother-infant attachment)
Elements of the cycle of intergenerational transmission of mother-infant attachment?
- Maternal caregiving environment: pre [stress/trauma] and postnatal
- Neuroendocrine development of infant (DA, oxytoxin)
- Infant attachment behavior (strange situation procedure)
- Ongoing environmental influences (other relationships)
- Adult attachmet patterns (adult attachment interview)
- Maternal brain and endocrine response (fMRI for DA, peripheral blood for oxytocin)
And now we’re back to:
- Maternal caregiving environment….
What is a central factor at play in many of the elements of transmissio of mother-infant attachment?
Genetic variation and epigenetic adaptation!
Shaped by:
- maternal caregiving environment
- ongoing environmental influences
Shape:
- neuroendocrine development
- infant attachment behavior
- adult attachment patterns
- maternal brain and endocrine response
