Autonomic Nervous System
•  A division of the peripheral nervous system that is closely
associated with the spinal cord. The individual has very little
control over the responses in this division, thus the name,
autonomic. Two subdivisions.
Peripheral NS and Spinal Cord
Peripheral nervous system connects the central nervous system to:
•  the body s organs (autonomic nervous system), involuntary
•  and muscles (somatic nervous system), voluntary
•  Both involuntary and voluntary responses are conducted through the
spinal cord.
Spinal Cord reflex
•  A reflex is a rapid, automatic response to a stimulus. Organization of
automatic reflex behavior at junction of spinal chord
•  Dorsal side (Back) - Afferent (sensory) nerve travels from receptor to
spinal cord
•  Ventral side (Front) - Efferent (motor) travels from spinal cord to effector.
•  Spinal Reflexes not under conscious control, but brain has some control.
E.g., seizures.
A simple sensory-motor (reflex) arc
Dorsal
Ventral
Brain divided into three parts: Hindbrain,
midbrain, forebrain.
The most complex three pounds in the universe
Forebrain, Midbrain, Hindbrain
Hindbrain
Brain
Brain
Forebrain
Hind Brain-oldest part of brain
•  Medulla primarily concerned with life support e.g. heart rate, breathing,
muscle tone, circulation. Cessation of activity in hind brain required for
determination of brain death. It also relays sensory information from
the various parts of the body to the brain and sends back motor messages
through it. Also Medulla is crossover point of axons to brain. Messages
for right side of body go to left side of brain, and vice versa.
•  Reticular Formation receives input from sensory neurons and sends
outputs to Thalamus and then to forebrain. Regulates arousal of brain.
Controls consciousness, damage leads to coma. Involved in sleep
wakefulness cycle and alertness.
•  Cerebellum is important for coordination and timing. It does not initiate
action but it is responsible for integrating and smoothing our actions.
Damage to cerebellum results in impairments in motor movement and
balance. Police test cerebellums on weekends.
•  Pons relays information from the cerebellum to the rest of the brain.
•  Cerebral cortex
Subcortical Structures
•  Thalamus relay station for all sensory information going to
cerebral cortex. The brain s switch board. Routs sensory
messages to the right location. More than switchboard. May also
filter important and unimportant information by accentuating it.
•  Hypothalamus responsible for many of the homeostatic functions,
such as salt, glucose, and temperature regulation, as well as
motivated behaviors. Four F s. Also areas that can be extremely
pleasurable. Direct connection with pituitary.
•  Pituitary Gland. Master gland of the endocrine or hormonal
system. Receives hormonal and neural instructions from the
hypothalamus and then sends hormonal messages to other glands
in the body.
Subcortical Structures
Limbic System
Limbic system important emotional
organization.
Hypothalamus
• Important in motivation and emotion.
Location of reward centers.
Amygdala
• Active under fear conditions. People
with damaged amygdalas find it
difficult to avoid dangerous situations,
rate their level of fear of lower than
normal. Also important in aggressive
reactions.
• Hippocampus
• Important in establishing memories
of important events. Damage to this
structure creates lapses of memory or
inability to create memories.
Brain
Forebrain (continued) Cerebrum.
Cerebral cortex or outer surface of the brain. Contains the
majority of neurons, and 20% of circulating blood
although only 2.5% of body weight.
–  Most recently evolved.
–  Hierarchical organization of behavior. In higher animals,
cerebrum tends to control lower centers
–  1/10 inch thick. Wrinkled surface creates more space for
neurons in parts you can t see(3/4)
–  100 Billion neurons, post mitotic, redundancy issue
–  400 Billion glial cells
–  Importance of stimulation for organization
Lobes of the Brain
Division of Cerebrum
Cerebrum, Two major divisions. Right and left hemispheres,
joined by corpus callosum. Each hemisphere further
divided into four, parts of which are called projection or
primary areas:
–  Frontal lobe-motor area for opposite side of body
–  Parietal lobe-sensory for opposite side of body
–  Occipital lobe-visual, right occipital lobe = left visual field
and vice versa
–  Temporal lobe-auditory
Use, is an important principle in normal brain development
•  Size = function
Phantom Limbs
Studying the brain
Case study of brain damaged patients-damage often not restricted in
location to give accurate assessment and depends on naturally
occurring events
Electroencephalograph (EEG)-Gross measure of neural activity
Electrical stimulation of the brain (ESB) – limited use in human
patients, more in animal
Positron-emission Tomography, PET scan
•  Volunteers injected with a low dose of a radioactive sugar.
Detectors around the person s head pick up the release of gamma
rays from the sugar concentrated in active brain areas. Shows
activity of brain indicated by uptake of radioactive nutrients
Magnetic Resonance Imaging (MRI) – Computer builds three
dimensional surface of brain by measuring changes in magnetic fields
Functional Magnetic Resonance Imaging (fMRI) – monitors blood and
oxygen changes in brain to show changes in activity and in what areas
of the brain
Brain
Association Areas – Unlike projection areas there is no direct input or
output from outside the brain. Eighty percent of brain is association
areas.
Prefrontal cortex - The story of Phineas Gage – Early evidence for the
importance of association areas for higher functions.
Changes in Phineas
• Capricious,
perseverative, lack of
foresight, disorganized,
tactless, profane, lacking
social conventions, and
dishonest. No longer the
same old Phineas.
•  Evidence suggests
involvement of prefrontal
cortex in the monitoring,
organizing and direction
of our thought processes.
• Perseveration
Phineas Gage
RED YELLOW
RED
BLUE
GREEN RED YELLOW RED
BLUE
Lobotomy
GREEN
RED RED YELLOW BLUE YELLOW
GREEN GREEN BLUE YELLOW RED
RED GREEN RED GREEN YELLOW
RED BLUE GREEN YELLOW BLUE
Other Association Areas of the Brain
Variety of Cortical Association
areas of the brain accomplish
tasks to create coherent world
•  Prosopagnosia (lack of face
recognition)- Typically underside
right temporal lobe. Can t
recognize faces of strangers or
friends.
•  Damage in temporal/parietal
areas can lead to sensory
neglect.
Association Areas
Some functions such as language show lateralization.
•  Expressive aphasia - Broca s area(Left Frontal)
–  Tan s Brain. Inability to speak, trouble putting thoughts into
the motor movements that create words
–  Broca s area close to motor area for jaw, tongue, lips, larynx
so on
•  Receptive aphasia - Wernicke's area(Left Parietal-temporal)
–  Inability to understand speech but talks freely and fast but
make little sense e.g. I was over the other one, and then after
they had been in the department, I was in this one.
–  Difficulty is understanding the meaning of words needed to
express what they intend to say.
•  Recovery from aphasia depends on age at which damage occurred.
Split - Brain Patients
Split brain -- Began as an attempt to alleviate the effects of
severe seizures
•  Corpus callosum cut to prevent seizures
•  Patients show little change in behavior
•  Effects can be observed in tests which are designed to send
different information to each hemisphere
•  Brings up the issues of the seat of consciousness and
whether there is an executive agent in the brain
Figure 6.10 Testing the divided brain
Myers: Psychology, Ninth Edition in Modules
Copyright © 2010 by Worth Publishers
Figure 6.11 Try this!
Myers: Psychology, Ninth Edition in Modules
Copyright © 2010 by Worth Publishers
Integrator Demonstration
Three Types of Neurons
•  Sensory neurons carry information from sense organs to
the central nervous system.
•  Motor neurons carry messages from the central nervous
system to muscles, glands and organs.
•  Interneurons, connecting neuron
Excitatory and Inhibitory Influences
Components of the Neuron
Neurons are a unique type of cell that can receive and
transmit information electrochemically.
–  Dendrites: receive information from other neurons
–  Cell body: creates transmitter molecules
–  Axon
•  Terminal buttons of the axon contain synaptic vesicles
that release neurotransmitters into a space called the
synapse
–  Axon Hillock, the point at which chemical transmission begins
Neuron
Neuronal Communication
•  Resting potential – base charge of neuron–70 millivolts.
- - Negative charge maintained by sodium/potasium pump.
Sodium(NA) outside Potassium(K) inside.
•  Threshhold around -60
The Action Potential(AP)
During the AP, NA+ ions flow into the cell raising the membrane
potential to +40 mV, producing the spike
•  The restoration of the membrane potential to -70 mV is produced by an
opening of channels to Potassium K+
•  Why is all or none important?
Overview of the Action Potential
NA ions
in
K ions
out
Saltatory Conduction
Myelin, fatty material that insulates the nerve cell, speeds up
conduction of nerve messages
The action potential occurs in nodes of ranvier rather than
each individual segment, like an express bus.
Multiple sclerosis is a disease breakdown of myelin
© 2004 John Wiley & Sons, Inc.
Details of the Synapse
Synaptic Transmission
Neurotransmitter binding
Autoreceptor
Enzyme deactivation
Reuptake
Neuronal Communication
Disruption of Neuronal communication
•  Novocaine
–  blocks pain by blocking sodium ions
•  Korsakoff's Syndrome
–  Vitamin B-1 deficiency
•  Lou Gherig s Disease
–  Breakdown of Myelin Sheath
Communcation between neurons
•  Binding of receptors by neurotransmitter based on "Lock and Key
•  What is the advantage of a Lock and Key system?
Neurotransmitters (Cont.)
Implications of Lock and key transmission of
Neurotransmitters in use of drugs
•  Agonist - chemical that mimics the action of neurotransmitter
•  Antagonist - chemical that opposes the action of neurotransmitter
Endorphins •  Show decrease sensitivity to pain, increased arousal, tendency to
persist in ongoing activities. Runner s high.
•  Morphine and Heroin (agonists) Uses same sites as endorphins
•  Naloxone (antagonist) blocks effects
Neurotransmitters
Acetylcholine
•  Motor neurons for skeletal muscles
•  Involved in attention, and memory, Alzheimer's
Monoamines
•  Serotonin - Sleep and mood changes, hunger and arousal
–  Deficit related to aggressive behavior, sleeplessness, and depression
•  Dopamine –Emotional arousal and pleasure, voluntary movement,
–  Deficit-Parkinson's disease
–  Excess-Schizophrenia,
•  Epinephrine, Norepinephrine-Alertness and Autonomic Arousal
–  Deficit can lead to depressed mood
GABA (Gamma Amino Butyric Acid) - Major inhibitory transmitter
•  Why does the brain have inhibitory transmitters?
•  Huntington's Chorea
The five key processes involved in communication at synapses are
(1)  synthesis and storage,
(2)  release,
(3)  binding,
(4)  inactivation or removal, and
(5)  reuptake of neurotransmitters.
Drugs
Drug Effects:
•  Alters the amount of neurotransmitter in synaptic cleft
–  Black Widow venom increases release of acetylcholine
–  Botulinus toxin prevents release acetylcholine
–  Amphetamines increase amount of norepineprhine available at
synapse
•  Mimics neurotransmitter to create similar effects
–  Nicotine stimulates acetylcholine sites
–  Heroin and morphine binds with neurotransmitter site for pain
•  Blocks receptor site so neurotransmitter cannot bind
–  Curare, cobra venom occupies binding site for acetylcholine
–  Halperidol, occupies dopamine sites, psychoactive drugs
•  Prevents reuptake of neurotransmitter
–  Cocaine blocks reuptake of norepinephrine, serotonin, dopamine
–  Prozac blocks reuptake of serotonin
–  Ecstacy stimulates release of dopamine and blocks reuptake of
serotonin
Endocrine System
Not part of the nervous system, but releases hormones into
blood stream which affect body organs.
Hypothalamus-Nervous system control center for the
Pituitary or master Gland
•  Pituitary Growth Hormone
–  Pituitary Dwarf , Giant , acromegaly.
•  Gonads
–  Sex Hormones, androgens (testosterone) and estrogens
(estradiol)
•  Adrenal Glands
–  Stress Hormones
Acromegaly
Endocrine System