8/14/2019 4 Neuroscience and Behavior Chpt 2
1/43
Neuroscience andBehavior
Chapter 2
57-97
8/14/2019 4 Neuroscience and Behavior Chpt 2
2/43
Introduction to Neuroscience
Everything psychological is
physiological.
In the early 1800s
phrenologywas the
beginning of neuroscience.Phrenology was the idea
that you could tell about a
persons personality or
mental skills from the shape
of their head.
8/14/2019 4 Neuroscience and Behavior Chpt 2
3/43
Biological Psychologists
Scientists who study the relationship
between biological activity and
behavior call themselves many things,
behavioral neuroscientists,physiological psychologists, or
biopsychologists.
Humans have the highest brain to
body weight ratio of any animal. Mostof that is due to our large cerebral
cortex or cerebrum.
8/14/2019 4 Neuroscience and Behavior Chpt 2
4/43
Neural Communication (p58-
65)
Neurons are
the most basicbuilding blockof allpsychologyand thenervous
system. Neurons are a
specializedcell. Cells arethe building
blocks of allliving things,the smallestunit of life thatcan exist.
8/14/2019 4 Neuroscience and Behavior Chpt 2
5/43
Neurons Each Neuron has a cell body, from which branches ofdendrites
receive messages from other neurons. Then the large axon fibertransmits the message to other neurons or muscles or glands.Axons can actually be several feet long. A myelin sheath coversthe axon and helps speed along the messages, finally themessage is released from terminal branches at the end of theaxon.
8/14/2019 4 Neuroscience and Behavior Chpt 2
6/43
5 Special Proteins In addition to normal cell activities neurons
make some special types of proteins thathelp them in their job.
Ion pumps (provide active transport of
certain ions in the cell membrane) Ion channels (passive transport) Messenger proteins (neurotransmitter) Receptor proteins (are used to receive
chemical signals) Enzymes (proteins) that degrade
neurotransmitters
8/14/2019 4 Neuroscience and Behavior Chpt 2
7/43
Types of Neurons
Sensory neurons Input: vision, audition,
smell, taste, touch, balance, proprioception
Interneurons most numerous, make up
most of the brain and allow internal
communication within the nervous system.
Motor neurons Output: movement,
behavior
8/14/2019 4 Neuroscience and Behavior Chpt 2
8/43
The Action Potential
Neurons are connected
not to just one other
neuron but to hundreds
or even thousands ofother neurons.
8/14/2019 4 Neuroscience and Behavior Chpt 2
9/43
Action Potential Every millisecond a neuron will be receiving messages
from these other neurons. Neurons receive only one of
two messages:- EPSP (excitatorypost synaptic potential)
FIRE!
- IPSP (inhibitorypost-synaptic potential)
Dont Fire! The neuron will calculate all the messages it gets, if it
gets more excitatory messages than inhibitorymessages it will reach its threshold and fire the actionpotential.
The action potential goes down the axon away from thecell body only.
Action potentials are an all or nothingaction, there areno partial action potentials.
8/14/2019 4 Neuroscience and Behavior Chpt 2
10/43
Action Potential
The action potential is an electrical chargecreated by chemical reactions
This is done by electrically charged atoms
called ions. The interior of an axon has an excess of
negatively charged ions making it negative. The outside of an axon has an excess of
positively charged ions making it positive. This normal state is called the resting
potential
8/14/2019 4 Neuroscience and Behavior Chpt 2
11/43
Action Potential When an neuron receives enough
EPSPs it changes the polarity ofthe selectively permeable axon
membrane closest to the cell body
and allows positive sodium ions to
rush in.
This depolarizes the next part ofthe axon and so on.
After the reaction the axon goes
back to normal in a short amount
of time called the refractoryperiod.
This process can repeat 100 or
even 1000 times a second.
8/14/2019 4 Neuroscience and Behavior Chpt 2
12/43
Active and passive ionmovement Ions are moved
in and out of theselectivelypermeablemembrane by ion
pumps andchannels in thecell membrane
http://www.brooks
Ion pump uses energyIon channel
doesnt need energy
Ions are movedin and out of theselectivelypermeablemembrane by ion
pumps andchannels in thecell membrane
http://www.brooks
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html8/14/2019 4 Neuroscience and Behavior Chpt 2
13/43
The Synapse andNeurotransmitters Action Potentials cause the release ofneurotransmitters from axon terminals into thesynapse, or a tiny space between where one neuronends and another begins.
8/14/2019 4 Neuroscience and Behavior Chpt 2
14/43
Neurotransmitter release Within 1/10,000th of a second neurotransmitters cross
the synaptic gap and bind to receptor cells on theother neuron, like the action potential this lets ionsenter the receiving neuron making either EPSPs orIPSPs
8/14/2019 4 Neuroscience and Behavior Chpt 2
15/43
Reuptake Reuptake is a process
by whichneurotransmitters are
reabsorbed by the
neurons who sent them.
This is importantbecause if it did not
happen the
neurotransmitters would
continue to triggerEPSPs as long as they
were in the synapse.
8/14/2019 4 Neuroscience and Behavior Chpt 2
16/43
8/14/2019 4 Neuroscience and Behavior Chpt 2
17/43
Neurotransmitters -continued
Undersupply linked toseizures, tremors and
insomnia
Major inhibitoryneurotransmitterGABA (gamma-
aminobutyric
acid)
Endorphins - are naturally occurring neurotransmitters that act as opiates.
They are released usually in times of great pain or vigorous exercise.
Because of the body has receptors for these transmitters this is why
opiates (morphine, vicodin, oxy-contin, heroin, etc.) are so effective at
producing a pleasurable, pain relieving feeling in humans. Becauseendorphins are not normally occurring in great quantities its very easy to
flood the body with them but then its very hard to replace them naturally
this is why opiates are so addictive.
8/14/2019 4 Neuroscience and Behavior Chpt 2
18/43
How Drugs and other Chemicalsaffect Neurotransmission
Drugs affectneurotransmission inone of three ways:
Agonists exciteareshaped enough just like
a regularneurotransmitter totrigger the same effect.
Antagonists inhibitmay be shaped enoughlike a neurotransmitter
to rest on a receptor siteblocking othertransmitters but it itselfdoes not trigger aresponse at the site.
8/14/2019 4 Neuroscience and Behavior Chpt 2
19/43
The Nervous System
The Nervous System
PeripheralCentral
(brain and spinal cord)
Autonomic(controls self regulated
Actions of internal organs
And glands)
Somatic(controls voluntary movements
Of skeletal muscles)
Sympathetic (arousing)
Parasympathetic (calming)
The three types of neurons, sensory, interneurons, and motor neurons
make up the Nervous System which is categorized into these majordivisions:
8/14/2019 4 Neuroscience and Behavior Chpt 2
20/43
The Peripheral NervousSystem As the chart indicates the peripheral nervous
system is made of 2 parts the autonomic and
somatic systems.
The somatic nerves control your voluntarymuscles, your movement.
The automatic system controls all the rest of
the things your body does constantly to keepyou alive that you dont think about, like
beating your heart.
8/14/2019 4 Neuroscience and Behavior Chpt 2
21/43
The Autonomic Nervous
System controls the glands and
internal organs.
The Sympathetic system isresponsible for the arousalof this
system for defensive action.
The Parasympathetic system is
responsible forcalmingthis
system, together they work to
regulate your bodys internal
functions to your everyday needs.
8/14/2019 4 Neuroscience and Behavior Chpt 2
22/43
Central Nervous System:Spinal Cord The spinal cord is an information highway
connecting the brain and the peripheral
nervous system.
The spinal cord is responsible for variousreflexes from sensation and pain such as
yanking your hand away from a flame. These
reflexes are usually caused by an interneuronconnecting the sensory and motor neurons
from a particular area.
8/14/2019 4 Neuroscience and Behavior Chpt 2
23/43
Diagram of a reflex a sensory and motor neuron connectedby an interneuron in the spinal cord
8/14/2019 4 Neuroscience and Behavior Chpt 2
24/43
Reflexes
While reflexes could happen in a headless
warm body any interpretation of sensation or
voluntary movement originates in the brain.
Therefore, people who have had their spinalcord damaged or cut often cannot feel or
move below that portion of their body, but
they could have reflexive reactions.
8/14/2019 4 Neuroscience and Behavior Chpt 2
25/43
Neural NetworksA grain of sand size speck of your brain contains 100,000 neurons with a billion
talking synapses. Neurons form connections with other neurons nearby them tomake work groups that can carry out specific tasks, like learning the piano.
Practice, repetition of using certain neuro-pathways strengthens them, and makes
you better at that task.
8/14/2019 4 Neuroscience and Behavior Chpt 2
26/43
The Brain (tools of discovery)
Lesion method destroying a part of an
animals brain and recording the results in
behavior.
Clinical Observation observing someonewho has had brain damage.
Manipulation stimulating part of the brain
and using modern instruments to record theresults, such as an EEG.
8/14/2019 4 Neuroscience and Behavior Chpt 2
27/43
The Brain (tools of discovery)
Electroencephalogram(EEG) records the overallelectrical activity of neuronsin the brain by recording thewaves of energy that
appear. Like studying a carby listening to the engine not very precise.
Computed tomography(CT or CAT scan) using a
series of x-rays a computermakes a map of your braininternally used to seebrain damage.
8/14/2019 4 Neuroscience and Behavior Chpt 2
28/43
The Brain (tools of discovery) Positron Emission Topography
(PET scan) by injecting users
with radioactive glucose (food)this machine sees which areas ofthe brain are most active duringcertain stimuli by measuring howmuch food is being used byactive neurons. Great for tellingus what different parts of thebrain do.
Magnetic Resonance Imaging(MRI) The MRI puts the brain ina strong magnetic field and thendistorts very briefly atoms with apulse of radio waves, by
recording the movement of atomsyou can create a computerizedpicture of the brain and of bloodflow (active areas) into the brain.
8/14/2019 4 Neuroscience and Behavior Chpt 2
29/43
The Brain: The Brainstem
The brainstem is the oldest part of the brain and
is well developed in animals as well as humans.
The bottom of the brainstem is called the medulla
it controls your breathing and heart rate The reticular formation helps organize
sensation nerves to go different parts of the brain
as well as affects arousal.
8/14/2019 4 Neuroscience and Behavior Chpt 2
30/43
8/14/2019 4 Neuroscience and Behavior Chpt 2
31/43
The Limbic System
A system of neural
structures right above
the brain stem that
influence emotions
such as fear and
aggression and basic
drives like hunger and
sex. Includes the
hypothalamus
hippocampus, and
amygdala.
8/14/2019 4 Neuroscience and Behavior Chpt 2
32/43
Limbic System
Amygdala primarily influences aggressionand fear
Hypothalamus directs several
maintenance activies like eating, drinking,body temp., has links to emotion andinfluences the endocrine system via thepituitary gland. Around this organ on many
animals is a distinct reward center that canbe stimulated to make the animals feelpleasure.
8/14/2019 4 Neuroscience and Behavior Chpt 2
33/43
Cerebral Cortex
The cerebral cortex is what people usuallythink of as the brain. Its the wrinkled top ofthe Brain. The reason for the folds is that it
increases surface area and allows for moreneurons. Glial Cells take care of neurons, they help
guide their connections, give them nutrients,
help cover axons with myelin sheaths, andthey can clean up ions and excessneurotransmitters
8/14/2019 4 Neuroscience and Behavior Chpt 2
34/43
8/14/2019 4 Neuroscience and Behavior Chpt 2
35/43
Functions of the Cortex
While we may separate regions of the brain
to help us study it we always have to keep in
mind that the brain is a very complex organ.
There is hardly ever just one region of thebrain that is being used for a particular task,
usually several areas at once are being used
for even the most simple things, like typing.
8/14/2019 4 Neuroscience and Behavior Chpt 2
36/43
Motor Cortex
At the back
of the frontal
lobe is the
motor cortex
which is in
charge of
muscle
movement
8/14/2019 4 Neuroscience and Behavior Chpt 2
37/43
SensoryCortex
Right behind
the Motor
Cortex is the
SensoryCortex where
your touch
sensations
areprocessed.
8/14/2019 4 Neuroscience and Behavior Chpt 2
38/43
Plasticity
The brain has the amazing ability to reorganize
itself.
If brain damage occurs, neurons do not grow back,
however neurons can change their function to allowthe brain to repair itself.
Thus if your middle finger were cut off, the fingers
next to it would become more sensitive because that
part of your brain that used to process sensationfrom the middle finger will now be used to process
more sensation from the other fingers nearby.
8/14/2019 4 Neuroscience and Behavior Chpt 2
39/43
The Divided Brain
Your brain is divided into two hemispheres.
The left side of your brain controls the right
side of your body and vice versa. The left
side of your brain includes most speechareas while the right includes a lot of visual
areas.
Each side talks to the other side via theCorpus Callosum so they can work
together.
8/14/2019 4 Neuroscience and Behavior Chpt 2
40/43
Hemisphere Specializations
Perceptual tasks are performed more in theright side of the brain (recognizing faces,pictures, art, subtle interpretation)
Speaking or calculating are preformed morein the left side of the brain. (recognizingwords,
Handedness is probably genetic, 95% of all
humans are right-handed. Left handedpeople on average live 3 years shorter forunknown reasons
8/14/2019 4 Neuroscience and Behavior Chpt 2
41/43
The Endocrine System
The Endocrine system is a system ofcommunication via chemicals called
hormones that it releases into the bloodstream. Hormones are chemical messengers mostly
manufactured by the endocrine glands that
affect other parts of the body. Manyhormones act just like neurotransmitters butare slower and have longer lasting effects.
8/14/2019 4 Neuroscience and Behavior Chpt 2
42/43
Adrenal Glands Secrete
epinephrine (adrenaline) and
norepinephrine which arouse
the body in times of stress
Pituitary Gland the master
gland under the influence of
the hypothalamus it regulates
growth and controls other
endocrine glands.Thyroid affects metabolism
Parathyroid affects calcium
levels
Pancreas regulates blood
sugar levels
Ovary secrets estrogen
(female sex hormone)
Testis secrets testosterone
(male sex hormone)
8/14/2019 4 Neuroscience and Behavior Chpt 2
43/43
Remember:
Everything psychologicalis physiological!
Top Related