Individual differences in environmental sensitivity part 2 Flashcards
Endophenotypic level
Level in between genetics and phenotype
Core mechanism of individual differences
in environmental sensitivity
initially, there was a predominant
focus on ‘stress reactivity
environmental events signaling
threat produce a set of complex,
highly orchestrated responses
within the neural circuitry of the
brain and peripheral
neuroendocrine pathways
findings as from the Boyce et al. studies however suggest that ‘biologically reactive’ individuals differ from less reactive individuals
in both high
-stress and low
-stress conditions
individual differences in the magnitude of
the biological stress response function
thus appears to regulate openness or
susceptibility to environmental influences
in a broad sense
biological sensitivity to context rather than
stress reactivity
Three main functions stress response
(Del Giudice et al., 2011):
the coordination of an individuals response to dangers and opportunities
encoding and filtering social and physical environmental cues
translating information from the environment into individual differencesin physiological and behavioral response patterns (e.g., bold or shy phenotypes)
→ marker of enviormental sensitivity
Two systems:
- Autonomic nervous system
- Endocrine system: HPA-axis
Autonomic nervous system
these responses result in an immediate, relatively automatic shift to a state of biological and behavioral preparedness
Sympathetic branch: fight or flight
Parasympathetic: rest
Co-regulation
Different biological systems are integrated and
co-regulated to response appropriately to
stress
Timing
Activation
main findings (boyce et al.)
children with low immune reactivity have
approximately equal rates of respiratory illnesses in
both high and low adversity conditions
as compared to the low reactive group, children with
high immune reactivity have higher illness incidences in
high stress situations and lower illness incidences in low
stress situations
these findings suggest that some children are
more responsive to the environment “for better
and for worse”
similar findings have been
reported from quasiexperimental research in rhesus
monkeys
genetic factors
a diverse array of candidate
genes has been studied in
relation to developmental
plasticity
Serotonine Transporter
gene (5-HTT)
three variants can be distinguished:
*homozygous for long allele (l/l)
* homozogyous for short allele (s/s)
* heterozygous (s/l) (in some studies the latter two are
taken together)
* ground-breaking work by Caspi et al.
(2003)
(s/s), (s/l) worse outcompes when more stresfull live events. Better outcomes when better parenting
Dopamine Receptor D4 gene (DRD4)
the DRD4 gene is known to be play a role in regulating the dopaminergic system
the 7-repeat variant of the DRD4 gene has been identified as vulnerability factor for ADHD and novelty seeking
however, there is also evidence
suggesting that the 7-repeat variant is a plasticity marker rather than a vulnerability marker
When DRD4 7+
Low peer presure less achol use
High peer preasure more alchol use
recently genetic research have moved beyond the
focus on single polymorphisms
This has been realized in different ways: look at more than one polymorphism in one and the same study
studying gene x gene x environment (GxGxE)
interactions
Low MAOA + 5httlpr ss,sl
More sexual abuse
Number of differentionation genotimes and resient functioning
The more differentiating the worse the outcome when maltreated and the more positive the outcome when non maltreated ecept for 2
+- same results for parenting quality and self regulation
epigenetic mechanisms potentially mediate
the association between
characteristics of the early environment and later susceptibility
DNA methylation
recent evidence suggests that not only early childhood experiences
predict DNA methylation, but also experiences in later
developmental stages
