Download SV3 Neuroscience n Behavior Oct 5 09

Neuroscience &
Behaviour
Ψ 100
October 5 ‘09
True or False
1)
A small amount of brain tissue from a person cannot be distinguished from that
of a monkey
2)
The human brain produces its own natural opiates that elevate mood and ease
pain
3)
Electrically stimulating a cat’s brain at a certain point can cause the animal to
cower in terror in the presence of a small mouse
4)
Both animals and humans seem to have reward centres located in the brain
5)
We ordinarily use only 10 percent of our brains
6)
Some people can write but are unable to read
7)
If a blind person uses one finger to read Braille, the brain area dedicated to that
finger expands
8)
Adult humans cannot generate new brain cells
9)
Some people have had the hemispheres of their brains split with no apparent ill
effect
Overview
Neural Communication
The Nervous System
The Endocrine System
The Brain
Learning Objectives
Explain why psychologists are concerned with human biology, and describe the ill-fated
phrenology theory
Explain how viewing each person as a biopsychosocial system helps us understand human
behaviour, and discuss why researchers study other animals in search of clues to human
neural processes
Describe the parts of a neuron, and explain how its impulses are generated
Describe how nerve cells communicate
Explain how neurotransmitters affect behaviour, and outline the effects of acetylcholine
and the endorphins
Explain how drugs and other chemicals affect neurotransmission, and describe the
contrasting effects of agonists and antagonists
Describe the nervous system’s two major divisions, and identify the three types of neurons
that transmit information through the system
Identify the subdivisions of the peripheral nervous system, and describe their Functions
Contrast the simplicity of the reflex pathways with the complexity of neural networks
Describe the nature and functions of the endocrine system and its interaction with the
nervous system
Learning Objectives
Describe several techniques for studying the brain
Describe the components of the brainstem, and summarize the functions of the brainstem,
thalamus, and cerebellum
Describe the structures and functions of the limbic system, and explain how one of these
structures controls the pituitary gland
Define cerebral cortex, and explain its importance for the human brain
Identify the four lobes of the cerebral cortex
Summarize some of the findings on the functions of the motor cortex and the sensory
cortex, and discuss the importance of the association areas
Describe the five brain areas that would be involved if you read this sentence aloud
Discuss the brain’s plasticity following injury or illness
Describe split-brain research, and explain how it helps us understand the functions of our
left and right hemispheres
Discuss the relationships among brain organization, handedness, and mortality
Naive Beginnings: Phrenology
A popular theory which
claimed that bumps on
the skull reveal our
mental abilities and our
character traits
Neural Communication
Neurons & how signals are generated
& propagated
How one neuron talks to others
Neurotransmitters & their effects on
behaviour
The Parts of a Neuron
How signals are generated
The Action Potential
An ACTION POTENTIAL (a Neural Message)
is:
A very brief shift in a neuron’s electrical charge that
travels along an axon
The action potential begins when stimulation of sufficient
intensity disrupts the resting membrane potential altering
the permeability of the cell membrane
The action potential results in the inside of the cell
becoming positively charged for a brief period (µs)
The action potential travels all the way down the axon in
an all-or-none response
How Neurons Communicate
Neuron to Neuron
Action potentials travel along the axon, and arrive at the
terminal buttons
Chemical Messengers (neurotransmitters) are stored in
synaptic vesicles
When the action potential reaches the terminal button,
vesicles fuse with the presynaptic membrane
Neurotransmitters are released into the synaptic cleft, the
microscopic gap between the terminal button of one neuron
and the cell membrane of another neuron
Neurotransmitter binds to receptors in a lock-and-key fashion
Neuron to Neuron
Postsynaptic Potentials are Voltage changes at a
receptor site on the postsynaptic cell membrane
Postsynaptic potentials are graded potentials
An excitatory postsynaptic potential is a postsynaptic
potential that moves the internal charge of the neuron
more positive or more likely to fire an action potential
An inhibitory postsynaptic potential is a postsynaptic
potential that moves the internal charge of the neuron
more negative or less likely to fire an action potential
Neural to Neuron
INTEGRATING POSTSYNAPTIC POTENTIALS
TEMPORAL SUMMATION occurs when two or more
postsynaptic potentials follow one another in rapid
succession at a receptor site
SPATIAL SUMMATION occurs when two or more
postsynaptic potentials occur simultaneously at different
receptor sites of the same neuron
Neuron to Neuron
TERMINATING NEURAL TRANSMISSION
REUPTAKE is a process by which neurotransmitters are
sponged up from the synaptic cleft by the presynaptic
membrane
ENZYME INACTIVATION occurs when neurotransmitters
are “cut-up” by enzymes leaving them inactive
Coding Stimulus Intensity
All action potentials are equal in size (voltage)
Stimulus intensity is coded as frequency of action
potentials
a | | | | | | | | | | |
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c |||||||||||||||||||||||||||||||||||||||||
Neurotransmitters &
Behavior
Neurotransmitters: More than 75 different
substances
Specific neurotransmitters work at specific
kinds of synapses
Specific enzymes clear the neurotransmitter
from the synapse to prevent continued
action
Neurotransmitters &
Behavior
Acetylcholine
Involved in memory, attention, arousal &
motivation (deterioration of Ach neurons
involved in Alzheimer’s disease)
Primary neurotransmitter at muscle beds
(activating)
Curare is a drug which blocks acetylcholine,
paralyzing the muscles
Neurotransmitters and
Behavior
GABA
Primary inhibitory neurotransmitter
Undersupply produces anxiety, insomnia
Endorphins
Internally produced chemicals that resemble opiates in
structure and effects (reduce pain by inhibiting neurons
that transmit pain messages to the brain)
Primarily function as neuro-modulators, that is, chemicals
that increase or decrease the activity of specific
neurotransmitters
Neurotransmitters &
Behavior
DOPAMINE: Plays a role in motor disorders,
such as Parkinson’s disease (undersupply)
NOREPINEPHRINE: Influences wakefulness
& arousal, as well as learning, memory and
mood (undersupply may lead to depression)
SEROTONIN: Affects emotions, arousal, and
sleep (undersupply leads to depression)
Drugs & Toxins
Botulism, Caffeine, LSD
Botulism: A microorganism that produces a toxin that
causes botulism. The toxin prevents the release of Ach,
which can lead to paralysis and/or death
Caffeine: Increases the release of excitatory
neurotransmitters by blocking the transmitter (adenosine)
that inhibits excitatory neurotransmitters
LSD (Lysergic Acid Diethylamide): Inhibits serotoninreleasing neurons. Hallucinations may result from lack of
dream suppression in conscious state
Drugs & Toxins
Drugs & Toxins
Drugs & Toxins
Agonists & Antagonists
Agonists:
Mimics the action of a neurotransmitter
A drug/substance that binds to a receptor of a cell and triggers a
response by the cell
Antagonists:
An antagonist acts against and blocks the action of a
neurotransmitter
An antagonist is the opposite of an agonist
The Nervous System
The Nervous System
CENTRAL NERVOUS SYSTEM -- the brain and
spinal cord
PERIPHERAL NERVOUS SYSTEM -- nerves
that lie outside the brain and spinal cord
(Messenger System for the CNS)
SOMATIC NERVOUS SYSTEM-nerves that
connect to voluntary skeletal muscles and to
sensory receptors
AFFERENT NERVE FIBERS-axons that carry
information inward to the central nervous
system from the periphery of the body
EFFERENT NERVE FIBERS-axons that carry
information outward from the central nervous
system to the periphery of the body
Central Nervous System
Peripheral Nervous System
The Nervous System
AUTONOMIC NERVOUS SYSTEM-nerves that
connect to the heart, blood vessels, smooth
muscles, and glands
SYMPATHETIC DIVISION-branch of the
autonomic nervous system that mobilizes the
body’s resources for emergencies (arousing
function)
PARASYMPATHETIC DIVISION-branch of the
autonomic nervous system that generally
conserves bodily resources (calming function)
The Sympathetic System
Prepares you for
action
Releases the blood
sugar level, increases
heartbeat & increases
blood pressure
The Parasympathetic
System
Prepares you for
relaxation
Promotes digestion,
slows heartbeat,
lowers blood pressure
The Autonomic System
Autonomic nervous system controls physiological arousal
Sympathetic
division (arousing)
Pupils dilate
Decreases
Parasympathetic
division (calming)
EYES
SALIVATION
Pupils contract
Increases
Perspires
SKIN
Dries
Increases
RESPERATION
Decreases
Accelerates
HEART
Slows
Inhibits
DIGESTION
Activates
Secrete stress
hormones
ADRENAL
GLANDS
Decrease secretion
of stress hormones
The Endocrine System
The Reflex
The Brain
Examining the Brain
Clinical studies examine the effects of brain
diseases or injuries on behavior (Post Mortem)
Ablation/lesioning is the surgical removal of brain
tissue and study of the result
Electrical stimulation of the brain (ESB) is the
activation of small areas of the brain by means of
electrical stimulation
Electroencephalography (EEG) measures and
records the electrical activity of the brain
Examining the Brain
MRI scanning (magnetic resonance imaging) uses a
magnetic field to produce an image of the brain's
interior (also fMRI)
PET scanning (positron emission tomography)
highlights areas of the brain in use as a radioactive
sugar is burned by brain cells
Chemical Stains make brain components visible to
the naked eye
ERPs: Event Related
Potentials
MRI & fMRI
The Brainstem
Brain Parts & Behavior
Hindbrain – oldest part of the brain
CEREBELLUM - coordination of movement and balance
MEDULLA - controls vegetative function
PONS - sleep, arousal, and connects cerebellum with the brain
stem
THALAMUS - structure through which all sensory information
(except smell) must pass to get to the cerebral cortex (The
sensory information transit hub)
RETICULAR FORMATION - regulates sleep and wakefulness
and modulates muscle reflexes, breathing and pain perception
Brain Parts & Behavior
Forebrain-largest and more complex region of the
brain
HYPOTHALAMUS - involved in the regulation of basic
needs like feeding, thirst, temperature
HIPPOCAMPUS - memory formation
AMYGDALA - fear and aggression
Brain Parts & Behavior
Cerebrum-the two large hemispheres that
cover the upper part of the brain
The Cerebral Cortex is the outer layer of the
cerebrum and contains 70% of the neurons
in the central nervous system
Corticalization is an increase in the size and
wrinkling of the cortex and is related to
intelligence
Structure of Cerebrum
Corpus Callosum
A thick bundle of fibers that connects the two cerebral
hemispheres
Left Hemisphere
Handles verbal processing, such as language, speech,
reading and writing
Controls & receives information from right side of body
Right Hemisphere
Handles non-verbal processing, such as that required by
spatial, musical, and visual recognition tasks
Controls & receives information from left side of body
The Cerebral Cortex
Organization of the Cortex
Organization of the Cortex
Lefthanders Die Young?
Nature vs Nurture
While driving a car, how might each of the following
parts of the brain be active?
Cerebellum
Medulla
Pons
Reticular formation
Thalamus
Hypothalamus
Amygdala
Hippocampus
Corpus callosum
Motor cortex
Broca’s area
Prefrontal cortex
Somatosensory cortex
Visual cortex
Auditory cortex
Wernicke’s area
Hand Usage Questionnaire?
For each item, indicate which hand you ordinarily use for each activity
With which hand do you:
1. draw?
2. write?
3. use a bottle opener?
4. throw a snowball to hit a tree?
5. use a hammer?
6. use a toothbrush?
7. use a screwdriver?
8. use an eraser on paper?
9. use a tennis racket?
10. use a scissors?
11. hold a match when striking it?
12. stir a can of paint?
13. On which shoulder do you rest a bat before swinging?
Left
Left
Left
Left
Left
Left
Left
Left
Left
Left
Left
Left
Left
Right
Right
Right
Right
Right
Right
Right
Right
Right
Right
Right
Right
Right
Either
Either
Either
Either
Either
Either
Either
Either
Either
Either
Either
Either
Either