BEHAVIORAL SCIENCE

Izben C. Williams, MD, MPHInstructor

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Developmental Journey

There are immensely complicated, mysterious, and beautiful transformation (biological, psychological and social) that take place between conception and old age

The period from CONCEPTION TO BIRTH sets the stage for all other development that we undergo as humans

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Some Prenatal Influences I

Genetic factors play a prominent role in determining the biological potential of a fetus.

The process of development is a sequential unfolding of normal events (and disorders) that are genetically determinedIn about 40% of children with ADD heriditary

factors are the basisDown syndrome (trisomy 21), Klinefelter

syndrome (XXY) and Fragile X syndrome are also genetically determined conditions

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Some Prenatal Influences II

Sex and survival factors:At conception 160 M : 100 FAt birth the ratio is aprox. 100 M : 100 F.

The surviving males have a higher risk for some degree of brain dysfunction

ADD ten times more frequent in malesGestational age, birth-weight, maternal

health, and perinatal factors may predict outcome

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Intrauterine Influences on development I

The intrauterine environment can significantly affect fetal brain development, and hence all future actions (behaviors)Animal models used to mimic adverse intra

uterine conditions in humansIntrauterine insults to the brain may be

acute or chronic

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Intrauterine Influences II

Even brief periods of hypoxemic compromise can have significant effects on the fetal brain causing neuronal loss and cerebral white matter damage

Subtle brain injury can occur, for example to a particular class of neuron, and this can have a significant effect on the function of a specific system, (eg hearing, vision)

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Intrauterine Influences III

Chronic mild placental insufficiency can result in long term deficits in neuronal connectivity

Repeated acute exposure to an inflammatory agent results in diffuse subcortical white matter damage and in some cases periventricular necrosis.

The timing and severity of these prenatal insults determines outcomes, in terms of the severity of the damage and the regions of the brain affected.

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Smoking and Alcohol Placenta mediates fetal growth and

influences long-term healthPlacenta to birth-weight ratio is regarded

as an indicator of the quality of placental function

Maternal prenatal smoking and alcohol consumption may influence fetal growth by either directly or indirectly altering the function of the placenta, and hence the development of the fetus. 

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Role of the placenta in feto-maternal exchanges

Reminder of placental role:Exchange process via membranous

exchange mechanismsThe fetal lungNutritive and excretory functionsProtective function and Immunological

barrierEndocrine function and protein transfer

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Some noxious trans placental influences

Some microbes can cross the placental barrier despite its efficiency: Sexually transmitted diseases (treponema

palidum, HIV, Neisseria GonorrheaFeto-toxic infections (rubella, toxoplasmosis,

cytomegalovirus, herpes simplex genitalis)Drugs (most antibiotics, corticosteroids,

teratogenic drugs such as Roacutane and Thalidomide

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Neonatal Capacities

At birth, the infant is pre-adapted to be cared for by the mother by the presence of attachment behaviors.Initial attachment behaviors (eg. crying

and clinging) increase the likelihood of maternal care and assist the infant in attaching to the mother

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Neonatal CapacitiesThe neonate possesses a number of innate

simple reflexes1. Moro reflex or startle reflex: flexion of

extremities in response to sudden stimulation

2. Palmar grasp reflex3. The rooting and sucking reflexes (both

aid in feeding the infant4. The Babinski reflex

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Development Sequences

Key: Consult table in text for schedule of motor, vocal, and sensory development sequences of the infant

Cognitive maturation: by age 18 to 24 months a child is capable of elementary trial-and-error reasoning. For example a child will attempt to place a

square object into a square opening of a form box after trying to insert it into the circular and triangular opening

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Birth and Post-partumTwo separate patients: Mother and InfantInfant status

APGARPrimitive reflexes (Startle, sucking, grasp,

Babinski)Maternal status

Physical statusPsychological status

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Theories of Development

Several theories, derived primarily from clinical experience and experiment.

Perhaps the best known systems in use today, are:Freud’s psychoanalytic theory, Piaget’s Cognitive developmental stagesEricson’s Psychosexual stages

The theories mostly identify developmental landmarks

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Concepts of Child Development

There is a lawfulness to all natural development, which serves as a framework within which we can assess and understand children and adults

Epigenesis: The development of an embryo from the successive differentiation of an originally undifferentiated structure (Epigenetic= after genes)Physical EpigenesisBehavioral Epigenesis

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Developmental Tasks

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Multiple developmental tasks

The pre-school child traverses several motor, social, and verbal/cognitive developmental zones by age six.

Key: See schedule of age-related developmental tasks, in text. Important to have an appreciation of these milestones

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Developmental Screening

There are many Developmental Screening-and-Assessment (S&A) Instruments for young children ages birth through five yearsLink to S&A instruments:

http://www.nectac.org/~pdfs/pubs/screening.pdf

These instruments emphasize Psychological, Social, Emotional and Physical Development

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Psycho-Social Development I

The principle psychological task of the first year of life is the formation of intimate differentiated attachment to mother of caregiver.

Failure of the infant to develop this specific early attachment may result in later defects in the capacity for empathy and for close warm reciprocal relationship.

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Psycho-Social Dev’nt IIThe social smile is an early marker of the

beginning development of a specific differentiated relationship, as are the preferential vocalization, visual pursuit and anticipatory gesturing of the 5-month-old infant in the presence of the motherEndogenous smiling develops from an innate

reflex response at birthExogenous smiling a response to the form of a

face – 8 weeksPreferred social smile a response to mother’s

face 16 weeks 9/15/2014 21

Psycho-Social Dev’nt III

Stranger anxiety begins at ~ 8 monthsObject relations (psychoanalytic theory)Response to Maternal

deprivation/separationPlay: its role and significanceAutonomy and self awareness

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Psycho-Social Dev’nt IV

Sociocultural factors:Innercity: increases risk of psyc. disordersADD: twice as high in low income familiesPsychosocial, or sociocultural,

retardation: deficient language, speech and cognitive skills associated with relative deficiency in adequate early stimulation (usually lower socio economic class)

Weaning from bottle shorter in middle class toilet training favors lower class

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