Download Neuroscience and Biopsychology

NEUROSCIENCE &
BIOLOGICAL
PSYCHOLOGY
AP Psychology
Ms. Brown
Myers - Ch. 2
Everything psychological
is also biological.
The Mystery of the Human Brain
• The brain is not completely understood.
How does our brain organize and communicate
with itself?
• How do our heredity and our experiences work
together to wire our brain?
• How do memories work in the brain?
•
• Scientists have discovered partial answers to
these questions but much is left to discover!
• Biological psychology – a branch of
psychology concerned with the links between
biology and, mental processes, and behavior.
Early Brain Research
• Phrenology – theory that the shape of
and bumps on the skull could reveal
mental abilities and character traits.
Early 1800s – mid-20th century (used to
justify racism and discrimination)
• Quackery (fraudulent medical practice)
•
•
Correctly focused attention on the idea
that various brain regions have certain
functions
Contemporary Brain Research
• In the last century, scientists have
discovered that the body is made of
cells.
• Nerve cells (neurons) conduct
electricity to “talk” to one another by
sending chemical messages across a
tiny gap that separates them.
NEURONS
Neuron
• Nerve cell
• Building block of the nervous system
• Found all over the body
Brain
• Legs
• Eyes
• Anywhere there are nerves – We will mainly focus on the basic neuron (below)
•
Dendrites
• The bushy extensions of a neuron that receive messages
Soma
• Cell body
• Contains nucleus – DNA, genetics, etc
Axon
• The extension of a neuron through which electrical messages pass
• Like the “backbone” of a neuron, if broken, the neuron dies.
A
X
O
N
DENDRITES LISTEN…
… AXONS SPEAK
The dendrites can receive messages to make the neuron fire or not fire.
If the message is to “fire,” the axon will send the message to the axon
terminals.
Myelin Sheath
• Layer of fatty tissue on the axon that…
Protects axon
• Speeds neural impulse (the message)
•
Multiple sclerosis – a disease in
which the myelin sheath
degenerates resulting in a
slowing of all communication to
muscles and the eventual loss
of muscle control
• Made of glial cells, which also bind neurons together.
Axon Terminals
• Branches at the end of an axon that send messages to the
dendrites of another neuron.
•
End in axon terminal buttons – contain vesicles that hold
neurotransmitters
Action Potential
• A neural impulse in the form of a brief electrical charge that travels
down the axon
•
A neuron fires an impulse when it receives a signal from sense receptors or
by the neurotransmitters from another neuron.
Direction of ACTION POTENTIAL
Synapse
• The junction between neurons.
Synaptic gap, synaptic cleft, etc
• Less than a millionth of an inch wide
•
I need 5 volunteers…
• Stand next to each other facing the class.
• Hold hands.
• The person farthest to the RIGHT wants to send a message to the
person farthest to the LEFT (without actually talking)– how will we
do this?
• When you feel the squeeze of your right hand, squeeze the right
hand of the person beside you.
• Right hand and arm
•
DENDRITES
• Chest
•
SOMA
• Left arm
•
AXON
• Left hand
•
AXON TERMINALS
How Nerve Impulses Work
• Threshold - the level of stimulation required to trigger a neural
impulse.
•
“all-or-none/nothing” principle
It either fires…
… or it doesn’t.
How Nerve Impulses Work
• Resting potential – the electrical charge of a
neuron at rest.
• Ions – electrically charged molecules
Inside axon: overall • Outside axon: overall +
•
“I’m so
HAPPY (+)
that I’m
OUTSIDE
playing!”
How Nerve Impulses Work
Neuron receives chemical message.
2.
Axon’s ion channels (holes in the axon membrane) open, allowing Na+
ions inside.
3.
Ion channels open like a domino effect, traveling from the soma to the
axon terminal.
4.
After the impulse passes, the neuron dips below resting potential and
cannot fire. The “ion pump” flushes out positive ions as it releases K+
ions outside.
Less than 1/100 of a second.
1.
How Neurons Communicate
• Neurotransmitters - chemical messengers that travel across the synaptic gap
between neurons
1.
Action potential reaches the axon’s terminal buttons.
2.
Buttons release neurotransmitters (chemicals)
3.
Travel across the synapse
4.
Bind/connect to receptor sites on the next neuron’s dendrites
Neurotransmitters
• Lock-and-key relationship between the neurotransmitter and the
receptor site.
•
When the neuron receives neurotransmitters, it will fire/not fire
Dopamine
Serotonin
Chart on pg. 58
•
Neurotransmitters
Many types of neurotransmitters that affect us differently and are
found in different parts of the brain
Neurotransmitter
Function
Examples of Malfunction
Acetylcholine
(ACh)
Movement
Learning
Memory
Too little - Alzheimer’s disease
Dopamine
Movement
Learning
Attention
Reward/Pleasure
Too little – Parkinson’s disease
Mood
Hunger
Sleep
Too little – depression
Norepinephrine
Alertness
Arousal
Too little – depressed mood
Too much – mania (linked to bipolar disorder)
GABA (gammaaminobutyric acid)
Inhibitory properties Too little – seizures, tremors, and insomnia
(calms neural activity) Alcohol increases GABA activity and slows brain activity
Glutamate
Excitatory properties
(stimulates neural
activity)
Serotonin
Too much – schizophrenia
•“Too much dopamine can make you ‘dopey.’”
•“Sarah’s tone is sad.”
Too much – migraines, seizures
Alcohol decreases glutamate activity and slows brain
activity
Endorphins
“Happy people don’t kill
their husbands!”
• Natural, opiate-like neurotransmitters
linked to pain control and pleasure
• Inhibit (block) pain signals
Ex: Runner’s high
• One of the top suggested remedies for
depression is exercise  naturally produce
chemicals that will stimulate pleasure and
happiness
•
• Too little – hypersensitivity to pain
• Too much – insensitivity to pain
INTERACTIVE NEURON
Brain, Neurotransmitters, and Other
Chemicals
• Cocaine, heroin, morphine, anti-depressants, anti-
psychotics, etc manipulate the production of
neurotransmitters.
• Too much manipulation  brain may stop naturally
producing similar transmitters.
• When the medication or drug is withdrawn, the brain
may be deprived of the neurotransmitters until the it
can naturally start producing its own again.
• Explains the uncomfortable withdrawal period when a drug
addict ceases using the drug.
Brain, Neurotransmitters, and
Other Chemicals
• Various drugs and substances can effect communication
at the synapse, by exciting or inhibiting a neuron to fire.
• Agonist – molecules that are similar to neurotransmitters and
can mimic their effects.
•
Eg: the venom of a black widow spider floods the brain with agonists similar to
ACh which results in muscle contractions, convulsions, and even death.
• Antagonist – a molecule that block a neurotransmitter’s
release
•
Eg: Botulin (a poison in improperly canned food), causes paralysis by blocking
the release of ACh from the sending neuron.
Neural Networks
• Interconnected neural cells; with
experience, networks can learn and
strengthen
• Neurons can receive and send
information from and to many
neurons at the same time.
• Neurons cluster to work in groups to
produce shorter, faster connections
(bound together by glial cells).
• Experience causes neural networks to grow
and strengthen  eg: practicing the piano
builds neural connections that help this
behavior.
IMPORTANT
•Communication WITHIN a neuron…
• ELECTRICAL – action potential
•Communication BETWEEN neurons…
• CHEMICAL - neurotransmitters
NERVOUS SYSTEM
Central Nervous System (CNS)
• The brain and the spinal cord
Peripheral Nervous System (PNS)
• the sensory and motor neurons that connect the CNS to the rest of
the body.
•
Everything but the brain and spinal cord
Nerves
• In the PNS
• Neural cables
• Connect the CNS to muscles, glands,
and sense organs
•
Ex: optic nerve connects the eye to the
brain
Eye = sense organ
• Optic nerve = PNS
• Brain = CNS
•
Nervous System Neurons
• Information travels through the nervous system in 3 type of neurons.
1.
Sensory neurons – (aka afferent neurons) carry incoming
information from the senses to the CNS
2.
Interneurons – CNS neurons that internally communicate between
sensory inputs and motor outputs
3.
Motor Neurons – (aka efferent neurons) carry out going
information from the CNS to muscles and glands
Sensory feel… Inter interpret… Motor move
The Spinal Cord and Reflexes
• CNS is the highway between the brain and the PNS.
However, sometimes the body can react without the
message reaching the brain.
• Reflex – simple, autonomic, inborn response to a sensory stimulus,
such as the knee-jerk response.
• Reflex pathway = 1 sensory neuron + 1 communication interneuron +
1 motor neuron
• Ex: simple pain reflex, simple knee-jerk reflex
The Spinal Cord and Reflexes
• Simple pain “reflex” – hand
jerks away when touching a
hot surface.
• The movement is initiated in the
spinal cord.
• Later, the pain is perceived in the
brain.
• Short delay between movement
and sensation.
What happens if the Spinal Cord is severed?
• Paralysis because sensory
messages cannot reach
brain and motor messages
cannot leave brain
• Paraplegia - patient can
still move two limbs
• Quadriplegia - all four
limbs are paralyzed
• Most famous case in
recent times was the actor
Christopher Reeves ( d.
2004)
Speed of Neural Communication
in the Body
• Everyone stand up, turn to your right, and await further
instructions…
• Shoulder squeeze
• Wrist squeeze
Somatic and Autonomic Nervous
Systems
• Somatic – controls the body’s skeletal muscles
•
Running, dancing, etc
• Autonomic – controls the glands and the muscles of internal organs
•
Heartbeat, digestion, sweating
PNS
Autonomic
Somatic – Skeletal
Somatic
Autonomic - Automatic
Sympathetic and Parasympathetic Nervous
Systems
• Sympathetic – arouses the body
• When someone is in crisis, we feel
sympathy for them
• Parasympathetic – calms the body
• Parasympathetic - paralyzing
Autonomic
Sympathetic
Parasympathetic
Let’s Put It All Together!
Nervous System
Peripheral
Central
(PNS)
(CNS)
Autonomic
Sympathetic
Parasympathetic
Somatic
THE ENDOCRINE
SYSTEM
Endocrine System
• The body’s “slow” chemical communication system made of glands
that secrete hormones into the bloodstream
• Hormones – chemical messengers manufactured by glands
Travel slowly in the bloodstream
• When hormones act on the brain, they can trigger interest in sex, food,
aggression, “flight or fight”
•
• Gland - An organ in the body that secretes a substance for use
somewhere else in the body
Hormones vs Neurotransmitters
Hormones
•
•
chemical messengers for the endocrine
system
Travel in the blood stream
Neurotransmitters
•
Chemical messengers in the brain
•
Travel in the brain in the synapse between
neurons
The endocrine system tries to keep a balance in the body while we
respond to feelings of stress, anger, fear, and exertion.
Pituitary Gland
• Small pea-shaped gland in the
limbic system of the brain
• Secretes growth hormone
• Most influential gland – “master”
gland (controls other glands)
• Controlled by the hypothalamus
• Liaison between the nervous system
and the endocrine system
• Acromegaly – caused by a tumor on
the pituitary gland
Adrenal Gland
• Pair of glands above the kidneys that
release adrenaline and noradrenalin
which helps to arouse the body in times of
stress
Increase heart rate, blood pressure, and
blood sugar for energy
• Hormones can last in the bloodstream after
the triggering event.
•
Daughter Lifts Car Off Dad
THE BRAIN
The Brain
• Brain size ≠ Intelligence
• Brain structure and complexity = Intelligence
Older Brain Structures
• Perform unconscious simple tasks necessary for survival…
Breathing
• Coordinating movement
• Heartbeat
•
• Brainstem
Medulla
• Pons
• Reticular formation
•
• Thalamus
• Cerebellum
Brainstem
• Oldest part and central core of the brain
• Beginning where the spinal cord swells as it enters the skull
• Responsible for automatic survival functions
Brainstem = area in the red box
Medulla
• The base of the brainstem
• Controls heartbeat and breathing
Pons
• Above the medulla
• Helps coordinate movement by relaying information to the cerebellum
Reticular Formation
• A nerve network in the brainstem
• Helps control arousal and sleep
When stimulated, it arouses your focus.
• If severed, you could enter a coma.
• Narcolepsy = malfunction of reticular formation
•
Thalamus
• The brain’s sensory switchboard, located on top of the brainstem
• Directs messages to the sensory receiving areas in the cortex and
transmits replies to the cerebellum and medulla
Cerebellum
• The “little brain” attached at the rear of the brainstem
• Processes sensory input and coordinates movement output and balance
•
An injured cerebellum would cause difficultly walking and keeping balance 
jerky movements
The Limbic System
• A doughnut-shaped system of neural structures at the border of the
brainstem and cerebral hemispheres
• Associated with EMOTIONS, MEMORIES, and SMELL
Hippocampus
• Amygdala
• Hypothalamus
•
Hippocampus
• In the temporal lobe
• Processes/stores memories
Amnesia can result from injury to the hippocampus
• “You’d remember if you saw a hippo on campus!”
•
Amygdala
• Two lima bean-sized structures above
the hippocampus
• Influences fear and aggression
Larger in males  more aggression
• Emotional problems result from which
part of the amygdala is
stimulated/damaged (too much
aggression, no fear, no emotions, etc)
•
Hypothalamus
• Below the thalamus
• Directs maintenance activities
Eating
• Drinking
• Body temperature
•
• Controls the pituitary gland
•
Interprets emotions and tells the
pituitary gland which glands need
to secrete hormones
• Reward/pleasure center
The Cerebral Cortex
• The intricate fabric of interconnected neural cells that covers the
cerebral hemispheres
• The body’s ultimate control and information-processing center 
higher level functions
Like bark on a tree – a thin surface that covers the brain hemispheres
• Contains billions of neurons and even more glial cells that bind together
and nourish them.
•
Lobes of the Brain
• Geographical subdivisions of the
cerebral cortex separated by
prominent fissures (folds) in the brain.
LOBES OF THE BRAIN AND THEIR FUNCTIONS (FPOT)
Lobe
Frontal
Where in Cerebral Cortex?
Behind the forehead
Parietal
At the top of the head,
towards the rear
At the back of the head
Occipital
Temporal
Roughly above the ears (near
the “temples”)
Function
Involved in speaking, muscle movements, and making
plans/judgments, “personality”
Receives sensory input for touch and body position
Includes the visual areas, which receive visual
information from the opposite visual field
Includes auditory areas, each of which receive auditory
information primarily from the opposite ear
Sensory and Motor Cortexes
Sensory Cortex
•
An area at the front of the
PARIETAL lobe that registers and
processes body touch and
movement sensations
Parallel to the motor cortex, behind
it
• Stimulation – sensation of being
touch depending on the area
•
Motor Cortex
•
An area at the rear of the
FRONTAL lobe that controls
voluntary movements
Sends outgoing movements
• Stimulation – movement in the
body depending on the area
•
Motor and Sensory Cortexes
• The
more sensitive a body region, the larger the area in the sensory
cortex
Visual and Auditory Cortexes
Visual Cortex
•
An area in the OCCIPITAL lobe that
processes vision from the opposite eye
Auditory Cortex
•
An area in the TEMPORAL lobe that
processes sounds from the opposite
ear
Association Areas
• Areas of the cerebral cortex that are involved in HIGHER
MENTAL FUNCTIONS such as learning, remembering,
thinking, and speaking.
• Any area in the cerebral cortex that is not in the motor, sensory,
visual, or auditory cortexes.
• In all 4 lobes
The Brain and Language
• Aphasia – impairment of
language, usually caused by
left hemisphere damage either
to…
• Broca’s area – frontal lobe, left
hemisphere, directs movement
necessary for speech
• Wernicke’s area – temporal lobe,
left hemisphere, involved in
language comprehension
Brain Plasticity
• The brain’s capacity for modification, as evident in the reorganization
following damage to the brain and in experiments on the effects of the
experience on brain development
•
SOME neural tissue can reorganize (not regenerate) as the brain repairs itself
after damage.
Blindness - when reading Braille, the brain area dedicated to that finger
expands as the sense of touch invades the visual cortex, which normally
helps people see
• Deafness - the auditory cortex receives no information from sound, so it
expands to new functions like visual tasks, which is why deaf people have
been found to have enhanced peripheral vision.
•
Lateralization
• The brain’s two hemispheres are not exactly alike and perform certain
functions
•
Ex: left hemisphere contains speech/language areas
Crash Course - Brain
Split Brain
• When the two brain hemispheres are not attached by the corpus callosum
• Corpus callosum
Band of neural fibers that connects the two brain hemispheres together and allows
them to communicate
• Possible to survive with a split brain, but may have difficultly integrating vision,
speech, and motor skills.
•
Studying the Brain
• Lesion – damage to brain tissue
• Allows us to study the functions of the brain in
circumstances that would be unethical to replicate
• Ex: Phineas Gage
• Gabrielle Giffords’ brain after attempted assassination
• still has difficulty speaking, limited vision in both eyes and no
peripheral in the right eye, and her right arm and leg are paralyzed.
She continues to undergo speech and physical therapy.
Electroencephalogram (EEG)
• Records the waves of electrical activity that sweep across the
brain’s surface; measured by electrodes placed on the scalp
Positron emission tomography
(PET) Scan
 Scan detects where a radioactive form of glucose goes
while the brain performs a given task.
 Glucose = energy
 Red areas = glucose activity = most active
(while performing that given task)
Magnetic Resonance Imaging (MRI)
• Uses magnetic fields
and radio waves to
images that
distinguish among
different types of soft
tissue, allowing us to
see structures within
the brain.
Functional MRI (fMRI) • A technique for revealing blood flow and therefore, brain activity
by comparing successive MRI scans
Crash Course – The
Chemical Mind