Programming the future - neurobiology Flashcards
Attachment & early life adversity
Parental caregiving >> shapes personality Neglect >> adult pathologies
Attachment
Dynamic, complex Bio-Behavioural synchrony : Eye gaze, vocalisations, affectional touch, positive affect >> needs/responsivity of the baby (Feldman 2012)
Feldman 2011 : classification des relations caregiver/children
task : play with tem, clean up everything …
HIGH/LOW synchronisation
Positive feedback
Oxytocin > Breast feeding > baby happy > reward (behaviour) > oxytocin …
Oxytocin
From hypothalamus > posterior pituitary (required for contraction, breastfeeding)
HPA axis
Hypothalamic Pituitary Adrenal
Cortisol & Oxytocin
Interact with each other
the one downgrade the other
Systems not regulated before 6 months => importance to protect the baby from stress during maturation of these axis
Oxytocin -> male
vasopressin
Oxytocin - voles study
Young et al. 2011
Voles (prairies & mountain)
Attraction for mated partner (compared to stranger)
No mate + oxytocin = preference compared to stranger
Receptors higher in prairies
OXYTOCIN INCREASES SOCIAL LINKAGE
Role of oxytocin
The role of oxytocin:
- Modulator of affiliative behavior
- Important for social preference
- Buffers the stress response
Oxytocin / vasopressin
Monkey study
Winslow 2003
Mother rearing VS Non mother rearing
MR
higher level of oxytocin
higher social behavior
NR
low level of Ox leads to pb because the sytem is downgraded
self centered/ no contact
higher level of cortisol : only when paired
Higher levels of Ox can downgrade stress reaction
Studies in humans
Institutional context can lead to neuroendocrinal dysregulation
cortisol
no evolution during the day (depressed)
returning to normal variation after adoption
=> interactive behavior btw parents/children
production of oxytocin
SSP
Strange Situation Protocole
Alone - stranger - parent
=> secure attached - insecured attached (anxious avoidant / anxious ambivalent) - disorganized attachement (level of cortisol oncreasing durin SSP even with parents)
Besides care what else matters ?
2 models
Individual vulnerability
environment
genes
Models
Vulnerability model
Differential suceptibility model
Vulnerability model
Differential suceptibility model
Genetics
BASICS
25 000 genes
Adenine Cytosin Thymin Guanin
23 pairs of chromosomes
Karyotype
DNA < replication >DNA > transcription > RNA > translation > PROTEIN
DNA : more than 6 billion nucleotides
Mutations
Deletion
Duplication
Inversion
Insertion
Translocation
Genetic disorders
Down syndrome
Williams syndrome
Single Nucleotide Polymorphism
SNP
Frequent alterations
Different configuration of the same gene
ACCTAGCTTCA
ACCTAGCATCA
Functional or non functional plymorphism
(coding/non coding part)
2 possible alleles
Other polymorphisms
Variable number of tandem repeat
SHORT = less expression of the gene
5-HTTLPR
BDNF val66met
S/S : more plastic genotype
cumulative effect of polymorphism
Indiscriminate behavior
Dangerous type of behavior, no look for adults of trust, no fear
Epigenetics
Signals from environment can trigger specific genes expression. Change in phenotype without change in genotype
- *Features of epigenetic mechanisms**
(a) structural modifications to chromatin either at the level of the histone proteins or the DNA,
(b) regulation of the structure and function of chromatin,
(c) affects on gene expression, and
(d) that these effects occur in the absence of any change in nucleotide sequence. The functional by product of the epigenetic modifications is that of a change in gene transcription.
Epigenetic modifications
DNA tighten tight => need to be loosened for transcription
Unmethylated = OPEN
Methylated = CLOSED (no gene expression)
Histones (H2A H2B H3 H4)
helps the DNA to be aligned in structure
Acetylated = OPEN
Deacetylated = CLOSED (no gene expression)
CpG island
Methylation happens on cytosin
C followed by G
Glucocorticoid receptor gene
DNA methylation - age
GLUCOCORTICOID RECEPTOR GENE
LLG display higher methylation
Transcription affected (less) >> nb of receptors generated (less) >> less receptors >> less negative feedback >> doesn’t decrease
The rearing context affects the methylation => gene expression
