Unit
6
Notes:
Biology
and
Behavior
The
Nervous
System
• the
nervous
system
is
divided
into
two
parts
– the
central
nervous
system
refers
to
the
brain
and
the
spinal
cord
– the
peripheral
nervous
system
refers
to
the
neural
pathways
going
to
and
coming
from
the
central
nervous
system
• sensory
(or
afferent)
neurons
relay
information
from
the
sense
receptors
to
the
spinal
cord
and
brain
• motor
(or
efferent)
neurons
relay
information
from
the
central
nervous
system
to
the
muscles
• reflex
arcs
allow
behavior
responses
without
processing
by
the
higher‐order
levels
of
the
brain‐‐
these
are
essential
for
survival
and
allow
for
rapid
motor
responses
• the
peripheral
nervous
system
can
be
divided
into
two
systems
– the
somatic
nervous
system
is
in
charge
of
voluntary
skeletal
muscles
– the
autonomic
nervous
system
is
in
charge
of
predominantly
involuntary
smooth
and
cardiac
muscle
activity
• this
is
important
for
heart
functioning
and
digestion
• the
autonomic
nervous
system
can
be
divided
into
two
systems
– the
parasympathetic
nervous
system
is
in
charge
of
the
body
at
rest
(slowing
down
biological
processes)
and
in
digestion
of
food
– the
sympathetic
nervous
system
kicks
in
during
times
of
stress,
fear
or
rage‐‐it
controls
our
“fight
or
flight”
behaviors
• the
dendrites
receive
incoming
information
• the
cell
body,
which
contains
the
nucleus,
is
called
the
soma‐‐it
is
the
living
part
of
the
neuron
• the
axon
is
the
long
fiber
over
which
outgoing
messages
travel
The
axon
terminal
buttons
are
the
transmitters,
sending
information
on
to
the
next
neuron
• the
space
between
neurons
is
the
synaptic
gap
• the
synapse
is
made
up
of
the
axon
terminal
buttons
of
one
neuron,
the
synaptic
gap,
and
the
dendrites
of
the
next
neuron
• there
are
several
neurotransmitters
or
chemicals
released
by
the
synaptic
vesicles
that
travel
across
the
synaptic
gap
and
affect
adjacent
neurons
• some
of
these
are
– dopamine
which
inhibitory
neurochemical
involved
in
Parkinson's
Disease
and
schizophrenia
– serotonin
which
is
an
inhibitory
neurochemical
involved
in
obsessive‐compulsive
disorder
(OCD)
as
well
as
sleeping,
arousal,
eating,
mood
and
depression
– acetylcholine
which
is
an
excitatory
neurochemical
involved
in
Alzheimer's
Disease
– norepinephrine
which
is
an
inhibitory
neurochemical,
involved
in
arousal,
wakefulness,
leaning,
memory,
depression
and
mania
Old
Methods
of
Brain
Study
• there
are
several
methods
of
brain
study
which
have
been
conducted
in
the
past,
with
new,
computerized
studies
rendering
more
accurate
information
• old
methods
of
brain
study
include:
– direct
stimulation
(or
microelectrode
method):
part
of
the
brain
is
stimulated
to
see
its
effect
– evoked
potential:
part
of
the
brain
is
monitored
to
see
if
external
stimuli
change
its
functioning
– lesioning
(or
ablation):
severing
or
cutting
parts
of
the
brain
– EEG:
measures
brain
wave
activity‐‐frequently
used
in
dream
research
New
Methods
of
Brain
Study
• new
methods
of
brain
study
include:
– MRI
:
magnetic
fields
from
radio
waves
– PET
:
positron
emission
tomography,
uses
radioactive
material,
good
for
metabolic
activity
of
the
brain
– CT
:
uses
X‐rays
to
look
at
soft
tissue
– SPECT
:
single
proton
emission
computerized
axial
tomography,
traces
blood
flow
in
the
brain
– SQUID
:
super
conducting
quantum
interference
device,
senses
tiny
changes
in
the
brain's
magnetic
fields
and
represents
them
in
3‐D,
deals
with
electrical
impulses
from
neural
firing
The
Three
Brains
• the
brain
can
be
divided
into
three
brains‐‐forebrain,
midbrain
and
hindbrain
• the
forebrain
includes:
– hypothalamus:
controls
hunger,
thirst,
sexual
behavior,
body
temperature
and
motivation
– thalamus:
the
relay
center
for
sense
receptors
– cerebral
cortex:
higher‐order
thinking
and
language
– corpus
callosum:
band
of
fibers
that
connects
the
two
hemispheres
• the
midbrain
includes:
– reticular
formation
(not
on
diagram):
the
alert
system
of
the
brain
• the
hindbrain
includes:
– cerebellum:
controls
balance,
fine
movement
and
muscle
tone
– pons:
the
sleep‐wake
cycle
– medulla:
controls
breathing,
heart
rate
and
blood
pressure
• the
brainstemthe
midbrain
and
hindbrain
combined
that
are
typically
considered
the
most
primitive
part
of
the
brain
• phylogeny‐‐the
study
of
the
evolutionary
development
of
humans
• also
listed
on
the
diagram
is
the
limbic
system
which
includes:
– the
amygdala
is
responsible
for
some
aspect
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