The Process of
Development
John Sargent, MD
Objectives of this lecture – to learn
1.) Framework for understanding
development
2.) Skill progressions through developmental
process
3.) Aspects of family and community that
promote development
Neurobiology of development
Neural tissues begin development and
differentiation at 2 weeks gestation
By 8 weeks cells begin to divide into cortical
and subcortical neurons
Between 12 and 20 weeks neurons migrate
toward cortical destination
The next step is connections among neurons
occurring throughout central nervous
system
These connections are refined to organize
cortical circuits and subcortical structures
(24 to 28 weeks gestation)
Number of neurons in humans peaks at 28
weeks gestation (40% more than in adult)
Further processes occurring during fetal life
include dendritic growth, synaptogenesis
and myelinization
Rapid growth and differentiation of central
nervous system tissues underlies the
vulnerability to toxins, drugs and alcohol
and nutritional status during fetal growth
Continued maturation of central nervous
system tissue includes both myelinization
and synaptic pruning which continues
from childhood through adolescence
Gray matter formation follows an “inverted
U-shaped curve” with peaks occurring
between 12 and 16 years of age
Gray matter areas that organize sensorimotor
activity mature first
Higher order association areas that govern
language and memory mature later in
preschool period
Frontal and prefrontal cortex continue
maturing through adolescence into young
adulthood reflecting maturation in
judgment, values, planning and impulse
control
Developing brain structures support
developing reading and language skills,
with interference with brain development
leading to dyslexia
Development of “inhibitory control” – the
capacity to control behaviors that conflict
with personal and societal norms also
occurs with age into young adulthood
This capacity is at the heart of cognitive and
emotional maturation, including the ability
to suppress automatic responses in favor
of less automatic responses
This capacity relies upon activation of
prefrontal cortices as well as thinning of
cortex and continuing myelination of
frontostriatal fibers
The capacity to read social and emotional
cues, including facial cues depends upon
the developing capacity of prefrontal
cortex to modulate limbic activity which
occurs during adolescence
Pruning of synaptic connections occurs in
unused connections
Mirror neurons and biobehavioral
reactivity have a great deal to do with the
development of empathy
Cognitive processing improvement is also
related to enhanced myelination increasing
the speed of neuronal transmission and
communication developed through
childhood
During infancy the infant’s capacities – smell,
suck, grasp, capacity to be comforted
reinforce maternal investment and care
Further infant abilities – gaze, smile, nuanced
cry, social engagement, snuggle, pleasure
upon satiation further reinforce parental
engagement
The influence of post partum depression,
chaotic home life, domestic violence,
parental substance abuse can be significant
especially in early childhood
Attachment relationship between child and
caretaker also significantly promotes and
regulates development
Secure attachment is a description of a
relationship that the child trusts to bring
hurt and emotional distress to, trusting that
the adult will assist with calming and
regulation
In a secure attachment relationship the child
is upset, the parent becomes upset, calms
herself and the child calms in response
2 types of insecure attachment relationships
have been described – avoidant and
resistant
Avoidant children suppress emotion while
resistant children persist in being upset
In situations of abuse children do not
develop a unified strategy for regulating
disruption and behave in an erratic and
dysregulated fashion
Secure attachment leads to more social
capacity, successful regulation of emotional
upset, improved peer relationships and
improved behavior regulation in school
Parental connections also lead to optimal
cognitive development in first 2 years of
life
Neural plasticity facilitates recovery from
early maltreatment, parental loss and early
adversity of other types
Plasticity is facilitated by consistency,
availability of support and coherent family
narratives
Competency, novelty and praise drive
development
Capacity to do things and consistent
availability of parental support assist
navigation of insecurity associated with
new challenges
Development leads to new skills – language,
peer relationships, learning and following
rules, gaining success in school and on
playground
Parental availability and responsiveness play
significant roles in reinforcement of
children’s developing skills
Important aspects of the community
that support development include
A.) Pediatric care, child mental health care
B.) Access to safe and supportive child care
and preschool
C.) Early childhood intervention to support
maximal development
D.) Home visiting, supportive
neighborhoods
E.) Adequate effective schools with
committed engaged teachers
F.) After school opportunities
G.) Engaging spiritual communities
H.) Safe neighborhoods, meeting places &
playgrounds
I.) Coaches, leaders and programs to build
and develop individual talents
J.) Groups (like 4-A, scouts) which support
group participation and group success
Be aware of the role of temperament and
intrinsic capacities in engaging in family
and community supports
Development is based on genetic
endowment influenced by environmental
circumstances