Case 3 Raging hormones
1. What happens in the brain during puberty? (hormones)
Article Forbes
- Adolescence is a time of dramatic changes including rapid physical growth, the onset
of sexual maturation, the activation of new drives and motivations, and a wide array of
social and affective changes and challenges. This review focuses on behavioral
changes in this interval and is organized by the claim that a key set of these adolescent
changes are part of a more general re-orientation of social behavior. More specifically
we hypothesize that pubertal maturation is associated with the activation of social and
motivational tendencies, which in turn influence behavior and emotion in adolescence
depending upon interactions with social context. We focus on evidence for two
examples of these motivational changes: (1) increases in sensation-seeking
(motivational tendency to want to experience high-intensity, exciting experiences) and
(2) stronger natural interest in—and pursuit of—contact with peers and potential
romantic partners. We consider how these motivational changes contribute to the
broader social re-orientation of adolescence, including exploration of social
experiences, development of skills and knowledge relevant to taking on adult social
roles, individuation from family, and establishment of an individual identity, all of
which represent core developmental tasks during this period in the life span. The paper
also emphasizes the importance of investigating and understanding the direct
influences of puberty on behavior and disentangling these from the broader set of
changes during adolescent development
- Increase dopamine->increase sensitivity reward
Pubertal development
- The transition into adolescence is marked by pubertal development, which includes
activation of the hypothalamic–pituitary–gonadal (HPG) axis and the hypothalamic–
pituitary–adrenal (HPA) axis. Puberty is triggered by increases in the frequency and
amplitude of nocturnal pulses of gonadotropin-releasing hormone (GnRH) in the
hypothalamus.
- A critical frequency of GnRH pulses activates pituitary release of luteinizing hormone
(LH) and follicle-stimulating hormone (FSH) pulses, which in turn, activate the
gonads. In girls, this leads to ovarian secretion of estradiol, progesterone, and ovarian
androgens, and eventually to the development of ovulatory menstrual cycles. In boys,
LH pulses lead to testicular secretion of androgens. In addition to gonadal
development, puberty also involves important changes such as increases in adrenal
androgens, rapid growth in body size, changes in distribution of body fat, and
development of secondary sex characteristics.
- organizational–activational hypothesis: the same hormones that initially organize sex
differences in the body and the brain during fetal and early postnatal life are also the
hormones that exert activational effects on behavior during puberty
- puberty can be viewed as a period of re-activation of hormonal influences on behavior
and the brain. Brain development is highly sensitive to hormone influence perinatally,
but the activational effects of hormones do not simply occur during perinatal
development, as once thought
- In humans, variability in the onset and progression of puberty exists, and there is
evidence that environmental influences contribute to this variability. Specifically,
endocrine-disrupting chemicals, nutrition, and body size seem to play a role in this
variability
1
, - It is not known exactly what triggers the onset of puberty, although genetic factors and
experience appear to contribute
- Measurements puberty: s five stages on two scales: one for breast development in girls
and gonadal development in boys; and one for pubic hair development in boys and
girls. Other means of assessing puberty include menarche in girls, level of circulating
reproductive hormones (e.g., luteinizing hormone), bone age determination, and
measurement of uterine and ovarian volume
Challenges in research on puberty and behaviour
- First of all, it is important to note that a large number of the most influential studies of
adolescent cognitive, emotional, and brain development have contained no measures
of puberty at all. Because adolescence is defined by both pubertal maturation and
social changes, it is therefore difficult to disentangle the effects of social context on
adolescence from the effects of puberty
- Secondly, even among the studies that have obtained objective measures of puberty,
these are often based on questionnaire or self-rating of maturation, and it is often
difficult to disentangle age effects from pubertal maturation in samples with a broad
age range, because in most such samples, age and puberty are closely correlated with
each other
Adolescent behaviour influenced by puberty
- Models of hormones and behavior suggest that puberty has an organizational effect on
brain development and adolescent behavior, creating a foundation for long-term
patterns of behavior, including problem behaviors such as psychopathology
- associations between puberty and behavior cannot be assumed to reflect direct effects
of hormones on behavior
- hormones can have different influences on behavior during puberty than in adulthood
and depending on the behavioral context
sensation seeking
- the central component of sensation seeking can be understood as a motivational
tendency: wanting or liking high-sensation, high-arousal experiences. Thus, the
increase in sensation-seeking that appears to occur at the onset of adolescence (and
may be linked directly to the rise in reproductive hormones) is an example of the type
of motivational tendency
- sensation-seeking tendencies are correlated more strongly with puberty than age.
Related to risk behaviour. sensation-seeking was correlated not with age but with
pubertal maturation. Boys and girls with more advanced pubertal development had
higher ratings of sensation-seeking and greater drug use.
- Ventral striatum + amygdala
- sensation-seeking and impulsivity follow different developmental patterns. Sensation
seeking increases from age 10, peaks between 13 and 16 years, and then declines.
Impulsivity, on the other hand, steadily declines from age 10 to age 30. The authors
interpret their findings as pointing to explanations of the increased risk-taking that
occurs during early adolescence, when both sensation-seeking and impulsivity are
high.
Motivational tendencies: studies of social dominance and sexual behavior
- Social context—including composition of the social group, rank within the group, and
social experience—also changes meaningfully during adolescence and can interact
with hormones to exert its own influence on social behavior.
- when considering the role of puberty in social dominance behavior in humans, it is
critical to consider more than simply hormone influences. A more comprehensive
2
1. What happens in the brain during puberty? (hormones)
Article Forbes
- Adolescence is a time of dramatic changes including rapid physical growth, the onset
of sexual maturation, the activation of new drives and motivations, and a wide array of
social and affective changes and challenges. This review focuses on behavioral
changes in this interval and is organized by the claim that a key set of these adolescent
changes are part of a more general re-orientation of social behavior. More specifically
we hypothesize that pubertal maturation is associated with the activation of social and
motivational tendencies, which in turn influence behavior and emotion in adolescence
depending upon interactions with social context. We focus on evidence for two
examples of these motivational changes: (1) increases in sensation-seeking
(motivational tendency to want to experience high-intensity, exciting experiences) and
(2) stronger natural interest in—and pursuit of—contact with peers and potential
romantic partners. We consider how these motivational changes contribute to the
broader social re-orientation of adolescence, including exploration of social
experiences, development of skills and knowledge relevant to taking on adult social
roles, individuation from family, and establishment of an individual identity, all of
which represent core developmental tasks during this period in the life span. The paper
also emphasizes the importance of investigating and understanding the direct
influences of puberty on behavior and disentangling these from the broader set of
changes during adolescent development
- Increase dopamine->increase sensitivity reward
Pubertal development
- The transition into adolescence is marked by pubertal development, which includes
activation of the hypothalamic–pituitary–gonadal (HPG) axis and the hypothalamic–
pituitary–adrenal (HPA) axis. Puberty is triggered by increases in the frequency and
amplitude of nocturnal pulses of gonadotropin-releasing hormone (GnRH) in the
hypothalamus.
- A critical frequency of GnRH pulses activates pituitary release of luteinizing hormone
(LH) and follicle-stimulating hormone (FSH) pulses, which in turn, activate the
gonads. In girls, this leads to ovarian secretion of estradiol, progesterone, and ovarian
androgens, and eventually to the development of ovulatory menstrual cycles. In boys,
LH pulses lead to testicular secretion of androgens. In addition to gonadal
development, puberty also involves important changes such as increases in adrenal
androgens, rapid growth in body size, changes in distribution of body fat, and
development of secondary sex characteristics.
- organizational–activational hypothesis: the same hormones that initially organize sex
differences in the body and the brain during fetal and early postnatal life are also the
hormones that exert activational effects on behavior during puberty
- puberty can be viewed as a period of re-activation of hormonal influences on behavior
and the brain. Brain development is highly sensitive to hormone influence perinatally,
but the activational effects of hormones do not simply occur during perinatal
development, as once thought
- In humans, variability in the onset and progression of puberty exists, and there is
evidence that environmental influences contribute to this variability. Specifically,
endocrine-disrupting chemicals, nutrition, and body size seem to play a role in this
variability
1
, - It is not known exactly what triggers the onset of puberty, although genetic factors and
experience appear to contribute
- Measurements puberty: s five stages on two scales: one for breast development in girls
and gonadal development in boys; and one for pubic hair development in boys and
girls. Other means of assessing puberty include menarche in girls, level of circulating
reproductive hormones (e.g., luteinizing hormone), bone age determination, and
measurement of uterine and ovarian volume
Challenges in research on puberty and behaviour
- First of all, it is important to note that a large number of the most influential studies of
adolescent cognitive, emotional, and brain development have contained no measures
of puberty at all. Because adolescence is defined by both pubertal maturation and
social changes, it is therefore difficult to disentangle the effects of social context on
adolescence from the effects of puberty
- Secondly, even among the studies that have obtained objective measures of puberty,
these are often based on questionnaire or self-rating of maturation, and it is often
difficult to disentangle age effects from pubertal maturation in samples with a broad
age range, because in most such samples, age and puberty are closely correlated with
each other
Adolescent behaviour influenced by puberty
- Models of hormones and behavior suggest that puberty has an organizational effect on
brain development and adolescent behavior, creating a foundation for long-term
patterns of behavior, including problem behaviors such as psychopathology
- associations between puberty and behavior cannot be assumed to reflect direct effects
of hormones on behavior
- hormones can have different influences on behavior during puberty than in adulthood
and depending on the behavioral context
sensation seeking
- the central component of sensation seeking can be understood as a motivational
tendency: wanting or liking high-sensation, high-arousal experiences. Thus, the
increase in sensation-seeking that appears to occur at the onset of adolescence (and
may be linked directly to the rise in reproductive hormones) is an example of the type
of motivational tendency
- sensation-seeking tendencies are correlated more strongly with puberty than age.
Related to risk behaviour. sensation-seeking was correlated not with age but with
pubertal maturation. Boys and girls with more advanced pubertal development had
higher ratings of sensation-seeking and greater drug use.
- Ventral striatum + amygdala
- sensation-seeking and impulsivity follow different developmental patterns. Sensation
seeking increases from age 10, peaks between 13 and 16 years, and then declines.
Impulsivity, on the other hand, steadily declines from age 10 to age 30. The authors
interpret their findings as pointing to explanations of the increased risk-taking that
occurs during early adolescence, when both sensation-seeking and impulsivity are
high.
Motivational tendencies: studies of social dominance and sexual behavior
- Social context—including composition of the social group, rank within the group, and
social experience—also changes meaningfully during adolescence and can interact
with hormones to exert its own influence on social behavior.
- when considering the role of puberty in social dominance behavior in humans, it is
critical to consider more than simply hormone influences. A more comprehensive
2
