Hormones, Neurotransmitters & External Factors that Affect Mental Health Discussion Discuss how variations in hormones, neurotransmitters, development, and
Hormones, Neurotransmitters & External Factors that Affect Mental Health Discussion Discuss how variations in hormones, neurotransmitters, development, and/or external factors (think social interactions or environmental exposures for example) interact to affect overall mental health and make each of us unique individuals. Because remember, youre unique, just like everyone else. Chapter 8: Hormones &
Social Behavior
April
Psych 256 Hormones & Behavior
Spring 2020
Social Behavior
What is social behavior?
Interactions between individuals from which one or more benefit
What are some examples of social behaviors?
Affiliation, courtship, parental behavior, aggression
Affiliation: behaviors to bring animals together
Aggression: behaviors that keep animals apart
How can social behavior benefit health?
Social support and affiliation reduces mortality in numerous disease states
(most studied with cardiovascular function and heart disease)
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Social Behavior: Pros vs. Cons
PROS
CONS
1. Antipredator detection,
defense, and dilution
1. Increased disease transmission
2. Elevated foraging efficiency
3. Group defense of resources
4. Increased mating opportunities
2. Increased competition for
resources
3. Increased conspicuousness to
predators
These apply more to animals in the wild; what about humans?
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Social Behavior
We will talk about two main social behaviors:
Affiliation & Aggression
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affect
Affiliation Behavior Circuit
1. Sensory Systems
(input)
Oxytocin
Estrogen
Testosterone Vasopressin
Cortisol
2. Brain/Central
Nervous System
(integrator)
3. Muscles
(effectors)
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4. Behavior
(output)
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Affiliation: Hormones
Key Hormones: Estrogen & Testosterone
? Review: Where have we
heard of these before?
Context Matters
When mating is involved: sex hormones block affiliative behavior
?Estrogen/Testosterone = ? tolerance of close proximity of same-sex species
Ø/?Estrogen/Testosterone = ? social tolerance and prosocial interactions
Female Voles:
Give estrogen: females dont form social bonds with each other
Male Mice: (our lab and many others)
Breeding males (? Testosterone): fight with other males
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Affiliation: Hormones
Key Hormones: Estrogen & Testosterone
Context Matters
When mating is involved: sex hormones block affiliative behavior
within sex (not between sex)
?Estrogen/Testosterone = ? tolerance of close proximity of same-sex species
Ø/?Estrogen/Testosterone = ? social tolerance and prosocial interactions
How would this apply to humans?
-Think about ovarian cycling hormones
-How do testicular hormones fluctuate compared to seasonally
breeding animals? Is this as relevant?
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Affiliation: Hormones
Key Hormones: Oxytocin & Vasopressin
Review: Where have we heard of these before?
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*REVIEW*
What can voles tell us about
human relationships?
Whats different?
This is brain
tissue ?
Important for female behavior
Important for male behavior
(Insel is famous for discovering this)
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Stress & Social Support:
Cortisol & Oxytocin
Fight or Flight OR Tend & Befriend
? Reminder: most of human stress is psychological
? During times of stress humans release oxytocin (more with
ovaries)
? What affect might increasing oxytocin have?
? Social interaction during stress shuts off sympathetic NS and
encourages body to return to baseline
? Males: larger groups for well-defined purpose (ex. defense)
? Females: smaller groups focused more on socioemotional
bonds; show more affiliative behaviors (smiling, attention, etc.)
Taylor et al., 2000; Psychological Review
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Study 1
Stress & Affiliation: Humans
Procedure:
Stress or Control Task
male college students were
either asked to prepare for a
mock interview and mental
arithmetic test (stress) or just
read a passage aloud and
count numbers (control)
Fast Friends Procedure
Group A
Group B
Mock interview
(stress)
Read or count
(no stress)
Measure cortisol
Befriend
stranger in
waiting room
Befriend
stranger in
waiting room
Following stress or not
participants spent time getting
to know a stranger using
guided questions
Question: Did the high stress situation make a male
more likely to befriend or feel close to a stranger?
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Stress & Affiliation: Humans
Results:
Orange line: I added this to
highlight that the higher the
cortisol value, the closer
that person felt to the
stranger (how likely they
would be to befriend them)
?cortisol ? ?social
closeness (affiliation)
(in males)
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Study 2
Stress & Affiliation: Humans
Procedure:
Perceived Score in Competition
Immediately following competition in a
dog show, handlers were asked if they
thought they received a passing score
Perceived poor score: high stress
Perceived good score: low stress
Affiliative Behavior Measure
Time spent playing with or petting the
dog (affiliative behavior) was measured
in the 3min post competition
Question: Did males and females display different affiliative behavior if
they thought they performed well/poorly in competition (low/high stress)?
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Stress & Affiliation: Humans
Results:
All: cortisol levels were higher if
they thought they did poorly
(not shown)
Males: high cortisol corresponded
to decreased affiliative behavior
(comfort contact)
Females: high cortisol
corresponded to increased
affiliative behavior (comfort
contact)
Sherman et al., 2017; Hormones and Behavior
Females were more likely to seek
contact comfort during times of
stress compared to males.
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Study 3
Finding: Oxytocin increased trust in others when they were more stressed
Stress & Oxytocin: Trust
How does Oxytocin drive you to seek Social Support?
?Oxytocin increases feelings of trust in others
Methods
Subjects: 50M/50F college students
1. Sniff Oxytocin or Control
2. Social rejection scenario
3. Mood and trust levels measured
? Results
? Negative mood: spectrum measure of stress
? Trust: agreeableness personality trait
Cardoso et al., 2013; psychoneuroendocrinology
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Stress & Affiliation: Humans
Summary of three studies:
1. Cortisol may increase social closeness in males & females
A. Specifically, comfort contact in females
B. Males were more affiliative after (perceived) victory; females
were more affiliative after (perceived) defeat
2. Oxytocin, during times of stress, makes us more trusting
of others, causing us to seek social support
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Affiliation: Brain Areas Involved
Maternal Love
Shared Regions
?Orbitofrontal cortex
?Striatum
?Periaqueductal gray
?Medial insular
cortex
Romantic Love
?Anterior cingulate
cortex
?Hippocampus
?Hypothalamus
?Ventral tegmental
area
Significance: these
brain regions are
part of reward
circuitry or have
oxytocin/vasopressin
receptors.
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Aggression
What is aggression?
? behavior that keeps animals apart
? behavior with the intent of inflicting damage or other
unpleasantness on another individual
When does aggression occur?
? whenever the interests of two or more individuals are in conflict
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affect
Aggression Behavior Circuit
1. Sensory Systems
(input)
Testosterone Vasopressin
Estrogen
Serotonin
2. Brain/Central
Nervous System
(integrator)
3. Muscles
(effectors)
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4. Behavior
(output)
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Aggression: Hormones Involved
Forms of aggression are more commonly noted in those with testes
vs. ovaries.
Key hormones involved: Testosterone & Vasopressin
Key neurotransmitter involved: Serotonin
Androgens (in animals) have been linked to:
? Intermale aggression
? Territorial aggression
? Sex-related aggression
? Rank-related aggression
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Aggression: Testosterone
1.
Hormonally dependent behavior disappears when the source of
hormone is removed or actions of the hormone are blocked.
Testosterone ? Aggression (reduced)
2.
castration reduces aggression in
male animals
After the behavior stops, restoration of the hormonal source or the
hormone itself brings the behavior back.
Aggression
Testosterone ? Aggression
3.
testosterone replacement
therapy restores aggression in
male animals
As the hormone increases in the body the behavior increases. When
the hormone level is low the behavior is not seen.
?Testosterone ? ?Aggression
males are more aggressive than females in most species;
seasonal variations in T correspond to aggression;
aggression increases with the onset of puberty
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?Testosterone = Aggression?
Are humans with elevated testosterone more aggressive?
Administration of testosterone to healthy males (normal testosterone
levels) did not result in anger/aggression
? 1 time injection of testosterone (at level comparable to male birth
control) had no affect on aggressive behavior (self- and partner-reported)
? Males given testosterone for a week did not display higher levels of
aggression in anger eliciting situations (or as reported in surveys)
However other similar studies have noted a positive association between
androgens and aggressive behavior in healthy males
? Males receiving increasing doses of testosterone were more likely to
subtract, rather than add points (equal to money) from an opponent
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?Testosterone = Aggression?
Are humans with elevated testosterone more aggressive?
Females assigned at birth with CAH display increased aggression
? Mother-completed survey of behavior indicates increased aggression and
activity in daughters with CAH compared to daughters without CAH
Aggression in 3-11 year olds
Aggression Scale
3.5
3
2.5
2
1.5
1
0.5
0
Control
CAH
Females
Control
Males
Pasterski et al., 2007
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?Testosterone = Aggression?
Do Aggressive individuals have elevated testosterone?
Prison Inmate Population:
? violent crimes, more unruly behavior,
harsher judgment by parole board found in
inmates with blood testosterone levels at
top 5-10% of normal
? this is true for male and female inmates
Elevated testosterone likely does not
determine/induce aggression in humans,
however it can be a contributing factor when
combined with other factors such as
psychopathology and environment.
Figure 8.28
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Testosterone in the Brain
How can circulating testosterone affect aggression?
1.
Androgen-responsive pathway: receptors that respond to testosterone
or its metabolite DHT
2.
Estrogen-responsive pathway: receptors that respond to estrogen
derived from testosterone
3.
Synergistic/combined pathway: both androgens and estrogens signal
aggression together
In male mice: without estrogen receptors there is decreased aggressive behavior
when given testosterone only rare instances of aggression seen
Androgen + Estrogen receptors: located in the amygdala (which lesions studies
show is essential for aggressive behavior)
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Vasopressin
In humans:
Personality disorders: higher circulating vasopressin correlated with
history of aggression towards others
Intranasal vasopressin (males): brain activity to pictures of neutral
facial expressions was similar to activity of control brains to angry
faces (they were showing angry brain activity unnecessarily)
? Suggests that vasopressin affects how we interpret sensory stimuli
Intranasal vasopressin (males + females):
? males made aggressive facial responses to photos of male strangers and
perceived the photos as less friendly
? females made affiliative facial responses to photos of female strangers
and perceived them as more friendly
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Serotonin
?Serotonin = ?Aggression ?Serotonin = ?Aggression
? Depleting serotonin increases responsiveness to sensory and painful
stimuli (feelings of pain are more pronounced)
? Serotonin treatment reduces aggressive behavior (even in humans)
? Potential Mechanism: serotonin (like vasopressin) affects how we
interpret sensory stimuli and typically results in a positive reaction
? in its absence we react in an aggressive/negative way
Testosterone can alter Serotonin receptor expression
in aggression brain areas.
Turn on/off genes
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Important Brain Areas
Amygdala
Periaqueductal gray
Prefrontal
Cortex
Septum
Hypothalamus
Thalamus
Ventral
Tegmentum
These brain areas have steroid hormone receptors and serotonin receptors.
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Review
?What are the main hormones/neurotransmitters involved
in affiliation and aggression and how do they differ
between males and females in influencing behavior?
?How do hormones affect different sensory stimuli to
generate social behaviors?
?What are some purposes of social behaviors and what
are the risks and benefits of being social?
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Quiz 2:
Hunger, Thirst & Metabolism
Thursday, March 5 & Tuesday, March 10
Psych 256 Hormones & Behavior
Spring 2020
Homeostasis:
Internal Balance
Your body has optimal settings for:
? Body temperature
? Water level
? Nutrient levels: sodium, potassium, sugar, protein
When internal balance is thrown off in response to a
stimulus, behaviors such as hunger and thirst are
activated to regain homeostasis.
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Energy Balance
How does the body keep necessary energy levels
when eating is episodic and not continuous?
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Energy Use & Storage after Eating
brain
2a. Glucose is energy
for the brain.
2b. Pancreas senses
glucose in blood and
releases insulin.
liver
4. Glucose + insulin fuel muscles or
can be stored in the muscles and liver.
When you need more fuel this storage
is used first.
brain
pancreas
1. Food broken down in the
stomach into glucose, fatty
acids, and amino acids.
Nutrients sent into blood.
muscles
3. Glucose and
insulin travel in the
blood together.
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fat
5. Excess glucose is stored in fat.
6. Leptin hormone is released from fat and
tells the hypothalamus to decrease appetite.
4
Diabetes Mellitus
Type 1 Diabetes childhood diabetes
?Autoimmune disorder
?Cells in the pancreas that make insulin are destroyed by the
immune system
?Body makes little/no insulin
?Tissue such as muscles and the liver cant use glucose for fuel
?Treatment: insulin administration through injection or pump
? Pump system: can sense glucose levels and adjust the insulin
output (or manually set)
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Diabetes Mellitus
Type 2 Diabetes adult onset diabetes
? Insulin receptors throughout body become resistant to
binding insulin (and cells are denied access to glucose)
? Cells deprived of glucose signal for more insulin
? Fat (adipose) tissue last to become insensitive and stores
all of the glucose that cannot be used throughout the
body resulting in increased fat tissue
? Treatment:
? Early: diet low in sugar and processed foods
? Late: pancreas stops making insulin so it needs to be
administered to allow for any glucose utilization
Types 1 & 2: reduced insulin signaling leads to high blood glucose levels (hyperglycemia)
high blood glucose can damage neurons and blood vessels
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Ketogenic Diet
brain
Traditional Diet
*High carbohydrate/sugar
Low fat
Protein
2a. The brain gets
the limited glucose
for some energy.
Ketogenic Diet
Low carbohydrate/sugar
*High fat
Protein
fat
4. The liver breaks
down fat into
ketone bodies.
liver
1. Food broken down in the
stomach into glucose, fatty
acids, and amino acids.
Nutrients sent into blood.
2b. Fatty acids
travel in the blood.
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muscles
3. Fatty acids are
stored in fat.
brain
5. Ketone bodies are
used to fuel muscle
and are a source of
glucose for the brain.
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Hunger Behavior
How does the body tell the brain to eat or stop eating?
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Hervey, 1959; J. Physiol.
University of Cambridge
Hormonal Control of Food Intake
How did we know hormones (something traveling in the blood) control eating behavior?
Rat 1
Removed part of
hypothalamus
Overate until obese
Rat 2
Normal but connected to
bloodstream of Rat 1
Refused food until it starved
Finding: Rat 1s brain couldnt receive the signal
that it was full, but Rat 2s hypothalamus could
Bodies and bloodstreams are sewn together
parabiosis
? Rat 1: kept eating because it didnt know it was full
? Rat 2: kept receiving the Im full signal from the
blood of Rat 1 and wouldnt eat
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affect
Control of Food Intake
Time of day
Social Situation
Pleasurable Experience
Leptin
Insulin
Ghrelin
1. Sensory Systems
(input)
2. Brain/Central
Nervous System
(integrator)
3. Muscles
(effectors)
These cues tell us it is time to eat
Arcuate Nucleus
(hypothalamus)
4. Behavior
(output)
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Not directly affected by hormones
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Hormonal Control of Food Intake
Hypothalamus
?Leptin
High Fat Stores ?Insulin
?Ghrelin
Low Fat Stores
?Leptin
?Insulin
?Ghrelin
1. Fat stores in the body
and food being digested
control levels of leptin,
insulin, and ghrelin.
Arcuate
Nucleus
(ARC)
POMC
NPY
AgRP
Lateral
Hypothalamus
Area (LHA)
+
Paraventricular
Nucleus (PVN)
?MSH
Decreased Eating
NPY
AgRP
Increased Eating
2. Leptin, insulin, and ghrelin 3a. Under high fat store conditions the hormones cause POMC
activate the arcuate nucleus neurons to release ?MSH neurotransmitter which decreases eating.
of the hypothalamus.
3b. Under low fat store conditions the hormones trigger NPY/AgRP
neurons to release NPY & AgRP neurotransmitters which increase eating.
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Hormonal Control of Food Intake
Leptin (released from fat)
?Levels of leptin correlate with fat stores
?As fat is being used for energy leptin levels drop and the dropping level acts as a starvation cue
?High levels of leptin activate the hypothalamus to decrease eating, support reproduction & immunity
Insulin (released from pancreas)
?When insulin levels drop as food is absorbed, hunger is activated
?Insulin signaling in the hypothalamus indicates fuel levels in the body to help make decisions about eating
Ghrelin (released from intestines)
?High levels increase food intake
?Ghrelin inhibits every level of the HPG axis which inhibits reproductive behavior, acting as a cue that
insufficient energy is available
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Why crash diets dont work
1.
Each body has its own ideal Leptin baseline and body fat level
2.
Crash diet: suddenly eating little/no food in the hope your body will burn fat for fuel
3.
As fat stores drop leptin levels go down
4.
Dropping leptin levels will cue the brain youre in starvation mode and drive hunger until
you restore leptin levels to your bodys ideal level
Can you alter your eating pattern so leptin levels wont derail your plan?
? If you slowly restrict eating in small increments you can retrain your body to accept lower
and lower levels of leptin
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Hormonal Control of Food Intake
Eating behavior on a meal-to-meal basis (short time frame):
Cholecystokinin (CCK)
? released by the intestines after fat & protein are consumed
? activates the vagus nerve which signals to the hindbrain then hypothalamus
? you stop eating that current meal when CCK levels get to a certain amount
Corticotropin releasing hormone (CRH)
? released by the hypothalamus as the first step of the HPA Axis
? inhibits appetite
HORMONE…
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