Download Brain, Body, and Behavior

New Unit: Neuroscience and
Behavior

“Everything psychological is
simultaneously biological.”

Our goals for this unit:
Understand how the brain organizes and
communicates within itself.
 Understand how heredity prewires the brain and
how our experiences modify it.

Brain, Body, and Behavior
Brain Communication and the
Glandular System
Neural Communication-The Neuron




Nerve cell that transmits
electrical + chemical info
through body.
Body has 100 billion nerve
cells that serve various roles.
Each cell has short fibers
called dendrites that receive
info from nerve cells + send
to axon.
Axon is long fiber extending
from cell body—carries
message from cell to other
neurons.
Picture From:
http://www.usm.maine.edu/psy/broida/101/neuron.JPG

Cell body (Soma): neuron’s
main cellular space

Dendrites: receive messages
from other neurons

Axon: send messages to
other neurons
The Synapse




Junction point of two or
more neurons.
Space between axon end
and receiving dendrites.
(less than one millionth
of an inch)
Neurons work on
electricity, but won’t
jump over space.
The information cannot
pass through without the
aid of
neurotransmitters.
Neuron with Synapse
Picture From:
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/neurons_1.gif
Neurotransmitters



Axon that ends before
synapse have vesicles
which contain
neurotransmitters.
Neurotransmitter =
chemicals carry nerve
signals across the
synapse.
60 different
neurotransmitters known
Picture From:
http://www.drugdigest.org/dd/images/anxcells.gif
Neurotransmitters, cont’d…

Acetylcholine (ACh): neurotransmitter which
regulates bodily processes like muscular
movement; most common neurotransmitter


Botulism leads to decrease ACh release—
results in paralysis.
Venom of black widow leads to synaptic flood
of ACh resulting in violent muscle contractions
and convulsions.
Neurotransmitters, cont’d…

Dopamine – also used in bodily movement




Influences movement, learning, attention, and
emotion.
Deficiency plays role in Parkinson’s and
Alzheimer’s.
Some substances can trigger production.
Many drugs focus on releasing dopamine
mimicking feelings.
Adapted from Sadock, B.,& Sadock,V. 2003. Synopsis of Psychiatry. Philadelphia: LWW.
More Neurotransmitters


Serotonin – affects mood, hunger, sleep
and arousal.
Low Serotonin levels = depression
SSRI’s (Selective Serotonin
Reuptake Inhibitor)





Paxil, Zolaft, Lexipro, etc.
Serotonin is released from one
nerve cell and passed to the next.
In the process, some of the
serotonin released is reabsorbed by
the first nerve cell. (Reuptake)
SSRIs block the reabsorption of
serotonin into the first nerve cell.
It is this blocking action that causes
an increased amount of serotonin to
become available at the next nerve
cell.
This is how SSRIs affect the
balance of serotonin in the brain.
More Neurotransmitters

Norepinephrine- helps control alertness and
arousal.
More Neurotransmitters



Endorphins (short for endogenous
morphine).
Associated with mood and pain.
Explanation for “runners high”, also plays
a role in painkilling.