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Various factors can impact brain development:
1. Direct CNS injury or insult (e.g., stroke,
tumor, trauma)
2. Environmental factors (e.g., malnutrition,
sensory deprivation)
3. Environmental toxins (e.g., lead, radiation)
4. Psychosocial factors (e.g., quality of
mother-child relationship, level of available
stimulation, social support structures,
access to resources etc.)
How do these various factors
actually influence neurons and
their structure and function?
Epigenetics
Environmentally induced changes in
gene expression.
DNA is wrapped around other
proteins (called histones)
When the DNA is read it is said to be “expressed”
difficult to read
easier to read
In order for all of our DNA to fit in our cells, it
must be highly compacted.
DNA is wrapped around a cluster of proteins
called histones
Champagne et al., (2009) Current Opinion in Neurobiology
Gene expression requires unwrapping of DNA
Champagne et al., (2009) Current Opinion in Neurobiology
The Bidirectional Coupling of Levels
Meeting the challenge of homeostasis involves:
•
•
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•
•
central nervous system
autonomic (peripheral) nervous system
endocrine system
immune system
limbic system
The Brain/ Body Links
•
Autonomic Nervous System:
-Sympathetic system
-Parasympathetic system
autonomic nervous system
Autonomic Nervous System
HYPOTHALAMUS
The Hypothalamus
•The hypothalamus has 4 ways of using the
autonomic nervous system to regulate internal
behavior (such as respiration and heart rate):
- diminish or increase activity of the sympathetic
nervous system
-diminish or increase activity of the
parasympathetic nervous system
The Hypothalamus
•These adjustments are primarily accomplished
by the type of neurotransmitters released at
target organs or glands:
- acetylcholine (Ach) decrease activity
-norepinephrine (NE) increase activity
Homeostasis
Several critical features involved in maintaining
homeostasis:
• set point (optimal level system tries to
maintain)
• detector (sensitive to deviations from the set
point)
• use of negative feedback (it opposes the
action that started the activity in the first
place)
Hypothalamus
• The hypothalamus bridges nervous and
endocrine systems.
• For example, heat-sensitive nerve cells in the
hypothalamus receive “too cold” signals from
heat sensors in the skin - the hypothalamus
tells the pituitary gland to release a chemical
that triggers the release of thyroid hormone
into the bloodstream.
• Thyroid hormone in turn steps up the body’s
heat production by altering metabolic rate.
Hypothalamus and Homeostasis
• If the body’s water content falls, salt
concentration builds up in the blood and
special sensors warn the hypothalamus.
• It sends a signal (releasing factor) to the
pituitary gland to release vasopressin into the
bloodstream.
• This makes the kidneys reabsorb water
otherwise scheduled to be released as urine.
ENDOCRINE GLANDS
Endocrine System
Example: if blood pressure rises, sensors in the
kidney detect the rise and set in motion the
various processes that reduce blood pressure.
Introduction to Biopsychology
[PSB 4002]
Professor Robert Lickliter
DM 260 / 305-348-3441
[email protected]
website: dpblab.fiu.edu
Three generations at once are exposed to the same
environmental conditions (diet, stress, toxins, etc.).
ENDOCRINE GLANDS
Endocrine Glands Produce
Hormones
• Hormones affect behavior in two primary
ways:
-1. Organizational effects: influence the
developing structure of the organism in longlasting ways (examples include the effects of
estrogen and testosterone on primary and
secondary sexual characteristics). Brain
reorganization induced by fetal androgens
cannot be reversed.
Organizational Effects of Hormones
• Sex differences in brain structure:
corpus callosum is relatively larger in females
• the suprachiasmatic nucleus of the hypothalamus is
relatively larger in males
• hippocampus is relatively larger in males than females
• the left hemisphere of the cerebral cortex is thicker
than the right in females; in males, the right cortex is
thicker than the left
Hormones
2. Activational effects: prime the organism
for responding to certain stimuli in real
time. Are typically reversible and shortterm (examples of oxytocin and prolactin
in the expression of maternal behavior in
mammals).
Perception/Action Coupling
The Perceptual Systems
The Perceptual Systems
invariant sequence of sensory system onset in birds and
mammals
visual
auditory 
chemical 
vestibular 
tactile 
Developmental Time
Types of Animal Infants
• precocial: born with all sensory systems
functional
• (lambs, calves, foals, ducks, chicks)
Types of Animal Infants
• altricial: born with one or more sensory systems
not yet functional (kittens, puppies, rat pups,
mice, songbirds)
Which are we?