Download CLASS #1: 9 Jan 2001

CLASS #1: Tues, 9 Jan 2007
PSB 2000 -01, -02, -03, -04 Spring 2007
INTRODUCTION: THE BRAIN AND BEHAVIOR
I. OVERVIEW
● Attendance
● General information about mechanics of the class; syllabus
● What is “Neuroscience?”
● An example: how your instructor (Dr. Berkley) became a neuroscientist, and
what she studies.
II. THE NERVOUS SYSTEM
A. THE MIND-BODY DILEMMA
DUALISM
MONISM
mind  body
mind  body
B. IMPORTANT PHILOSOPHERS (besides ourselves)
● Hippocrates: 460-379 BC---brain is seat of intelligence.
● Aristotle: 384-322 BC---heart = mind/soul; brain serves as
radiator to cool overheated blood.
Monism
● Galen: 130-200AD---brain secretes fluids conveyed by
nerves to the body—behaves like a gland.
● Versalius: 1514-1564 ---mind/soul is the nervous system.
Dualism
● Descartes: 1596-1650: MIND  pineal gland  brain  body.
C. FUNCTION: The main functions of the nervous system are to organize and
control an individual’s appropriate interactions with her/his environment.
Examples:
 Neural input capabilities are appropriate to lifestyle of species: e.g., rodents
can detect ultrasounds (‘bat detector’)
 Impact of abnormal neural input can have social consequences: e.g., your
instructor’s hearing aids
 The nervous system is plastic. It learns and processes information so that
actions are appropriate to circumstances: e.g., pain—a motivating perception: horse
breaking leg in race; deer running from a lion; humans in the ER
D. EVOLUTION, THE GENETIC REVOLUTION AND ITS
SIGNIFICANCE FOR NEUROSCIENCE (if time)—Module 1.2 in your book.
PSB 2000
Class #2: Thurs 11 Jan 2007
cCELLS OF THE NERVOUS SYSTEMm
I. COMPONENTS OF A CELL
● Nucleus: chromosomes (23 pairs-humans)-DNA/genes; nucleolus (makes
rRNA-ribosomal RNA); nuclear membrane
● Cytoplasm: mitochondria (energy), ribosomes (synthesis of protein); endoplasmic
reticulum (rough; smooth); golgi complex, lysosomes.
● Plasma membrane
II. PROTEIN SYNTHESIS
● composition of DNA: double stranded molecule, with sequences of any of 4
bases attached in various orders to a skeleton made of a sugar (deoxyribose) and a
phosphate:
Guanine (G), Cytosine (C),
Adenine (A), **Thymine (T)
● compsition of RNA: single stranded molecule, with 4 bases on a skeleton made
of a sugar (ribose) and a phophate: G, C, A, and **Uracil (U)
● DNA  mRNA*
G

C
Genetic info in nucleus is transcribed to
mRNA. The mRNA* moves into the
C

G
cytoplasm and onto a ribosome, where
A

U
the mRNA is translated into a protein**.
T

A
*messenger’ RNA; **each sequence of 3 RNA bases codes for one AMINO ACID (example: G-C-G
= arginine). Proteins are composed of combinations of amino acids.
III. NEURONS
● dendrites, soma, axon hillock, axon, myelin sheath (node, internode), terminal branches,
terminal boutons (presynaptic swellings)
● variations in the arrangements of these elements
● synapses: specialized junctions between two neurons
● synapse composition: presynaptic swelling (vesicles, mitochondria, presynaptic membrane);
synaptic cleft; postsynaptic membrance and thickening
● synapse types axodendritic; axosomatic; dendrodentritic; axoaxonic
IV. CONNECTIONS BETWEEN NEURONS (“WIRING”): divergence,
convergence and plasticity
IV. GLIAL CELLS
● astrocytes: “nerve glue”, inactivate neurotransmitters, nutrition, cleanup,
potassium (K+) buffer
●oligodendrocytes  myelin (CNS); Schwann cells  myelin (PNS)
●microglia (associated with injury)
V. BLOOD-BRAIN BARRIER (if time)
PSB 2000
Class #3: Tues, 16 Jan 2007
ELECTRICAL ACTIVITY:
RESTING AND ACTION POTENTIALS
Communication between neurons depends on active (energy-requiring)
properties of the neuron’s plasma membrane.
I. MEMBRANE CHANNELS (FOR IONS**): 3 TYPES
TYPE
LOCATION
leakage
voltage-gated
Mostly axon, also
everywhere soma, dendrites
ligand-gated*
Dendrites and soma
(not axon), terminal
boutons
Type of potential for Resting
Action potential,
which the chanel is
sometimes synaptic
Synaptic potentials
potential
important
potentials
*Ligand-gated types: ● ionotropic (just ions) ● metabotropic (involves G-proteins)
+ + + II. RESTING MEMBRANE POTENTIAL: steady state voltage across
+ + membrane; inside of cell negative to outside; produced by:
● an unequal distribution of ions
OUTSIDE
OUTSIDE
INSIDE
between inside and outside of membrane: Na+ K+
● semipermeability of membrane
Cl● forces acting on movement of ions in solution
K+
A-
Na+
Cl--
Na+
Cl-
-concentration gradient; electrostatic (like forces repel; opposite attract)
● sodium-potassium pump (needs energy): pumps K+ in and Na+ out
III. ACTION POTENTIAL: A rapid, all-or-none, reversible change in
membrane potential of ~1msec duration (duration can vary)
● sequential opening , then closing of voltage-gated ion channels:
1st: Na+ chan. open (Na+ rushes in—causing depolarization; 2nd: K+ chan.
open (K+ moves out), causing repolarization and hyperpolarization.
● usually initiated at axon hillock (threshold is lowest there)
● propagates from there down to boutons (via passive, cable properties of
axon and saltatory conduction-if axon myelinated)
● refractory periods (absolute and relative) prevent it going in both
directions constantly; absol ref per + duration of APsets top frequency.
● conduction velocity = speed of conduction of action potential down the
axon; depends on diameter of axon and how it is myelinated; varies from
~0.3 meters/sec to ~120 meters/sec!
** IONS are electrically-charged molecules: cations are positively charged—such as potassium
(K+), sodium (Na+), calcium (Ca++); anions are negatively charged—such as chloride (Cl-),
some large proteins (A-)
K+
PSB 2000
Class #4: Thurs, 18 Jan 2007
SYNAPTIC POTENTIALS, TRANSMITTERS, DRUG ACTIONS
I. WHAT HAPPENS AT A SYNAPSE?
A. Transmitter release: AP activates voltage-gated Ca++ channels in the
presynaptic membrane, causing vesicles to fuse with presynaptic membrane and release their
transmitter into synaptic cleft.
B. Transmitter recognition: Receptors in the post-synaptic membrane recognize
and bind the transmitter.
C. Transmitter inactivation: 4 mechanisms of inactivation: ● reuptake; ● uptake
by post-synaptic neuron; ● glial uptake; ● enzyme deactivation.
D. Actions at post-synaptic membrane: If receptors in post-synaptic membrane
recognize the transmitter (=ligand-gated channels), the membrane’s conformation changes,
causing a change in ion movement across the post-synaptic membrane and therefore a change in
voltage across the membrane at that point. Depolarization = excitatory post-synptic potential
(EPSP); hyperpolarization = inhibitory post-synaptic potential (IPSP).
II. Summation of EPSPs and IPSPs across the membrane of the post-synaptic
neuron: EPSPs and IPSPs summate in time and in space. If the summation produces enough
depolarization to reach the neuron’s threshold anywhere on the membrane, then an action
potential will occur there and spread over the whole membrane. The threshold is usually lowest
at the axon hillock.
A. Types of effects of neurotransmitters on the post-synap. membrane:
● ionotropic: direct action on ion channels
● metabotropic: indirect, either via a G-protein, or a G-protein and a 2nd messenger
B. Types of neurotransmitters:
● acetylcholine
● monoamines: --indolamine: serotonin
--catecholamines: dopamine, norepinephrine, epinephrine
● amino acids: glutamate, GABA, glycine, many others
● peptides (contain amine groups-NH2): endorphins, substance P, oxytocin,
neuropeptide Y, vasopressin, many others
● purines: adeniosine, ATP, others
● gases: nitric oxide, carbon dioxide (NO, CO)
● others: cannabinoids, others…
III. DRUG ACTIONS:
● Concepts: antagonist, agonist, affinity, efficacy, dependency, addiction
● Drugs can influence synaptic activity in a huge number of ways, by acting on any of the
processes associated with neurotransmitter action, such as: ●synthesis of transmitters, their
receptors and their inactivators; ●release of transmitters; ●inactivation of neurotransmitters,● the
recognition of neurotransmitters, etc…
PSB 2000
Class #5: Tues, 23 Jan 2007
GROSS ANATOMY-part 1Y
I. DEVELOPMENT OF THE NERVOUS SYSTEM
A. Origin: The early embryo differentiates into groups of cells that are the origin of ectodermal
tissues, mesodermal tissues and endodermal tissues. The nervous system originates from ectodermal cells.
B. Process: A thin sheet of cells forms on the dorsal* surface. This sheet curls up into a tube-like
structure along the length of the developing body. The most dorsal part of this tube (where the two ends of the
sheet have joined) is composed of neural crest cells. The rest of the tube is composed of neural tube cells. The
neural crest cells proliferate and migrate out into the rest of the body, thereby forming the PERIPHERAL
NERVOUS SYSTEM. The neural tube cells proliferate to enlarge the tube, thereby forming the CENTRAL
NERVOUS SYSTEM, whose rostral* part is the BRAIN, and whose caudal* part is the SPINAL CORD.
II. PERIPHERAL NERVOUS SYSTEM Derived from neural crest cells. Consists mainly of the
nerves (groups of axons) and ganglia (groups of nerve cell bodies) that lie outside the spinal vertebrae and skull.
A. Cranial nerves: 12 pairs
MEMORIZE
THESE!
I = olfactory
II = optic
“On Old Olympics Towering see p. 88,
III = oculomotor
Tops A Finn And German
Table 4.4 in
IV = trochlear
Viewed Some (or A) Hat(s)” your text
V = trigeminal
VI = abducens
VII = facial
VIII = auditory (or statoacoustic)
IX = Glossopharyngeal
X = vagus
XI = spinal accessory (or accessory)
XII = hypoglossal
B. Spinal nerves: 31 pairs (humans):
● 8 Cervical = C1-C8
● 5 Sacral = S1-S5)
● 12 Thoracic = T1-T12
● 1 Coccygeal = Co1
● 5 Lumbar = L1-L5)
C. Divisions:
● Somatic: those nerves that innervate skin and muscles
● Autonomic: those nerves that innervates internal organs. It has 2 subdivisions
--Sympathetic --Parasympathetic
III. SPINAL CORD
A. Segmentation: There are 31 segments that are associated with each of the 31 pairs of spinal
nerves (named the same way; e.g., T12 segment receives input from/ sends output through T12 spinal nerves.
B. Organization: “Grey matter” surrounded by “white matter.” Through the middle runs a “central
canal” that contains cerebrospinal fluid (CSF). Grey matter is composed of neuronal soma and synapses. White
matter is composed of axon tracts heading rostrally to the brain or descending from the brain to the spinal cord.
C. Association with spinal nerves: Each spinal nerve is divided in 2 parts inside the spinal
vertebrae. One division enters the dorsal* aspect of the spinal cord. It is called the “dorsal root,” and brings
information into the spinal cord (afferent*, sensory input). The other division exits from the ventral* aspect of
the spinal cord (“ventral root”), bringing information out to the body (efferent*, motor output). This
arrangement, discovered by Bell and Magendie (thus the “Bell-Magendie Law”) creates a situation in which the
dorsal part of the spinal cord has mainly sensory functions, whereas the ventral part has mainly motor functions.
The cell soma for the the nerve fibers of the dorsal (sensory) division of each spinal nerve are located outside the
spinal cord in ganglia (“dorsal root ganglion”). These ganglia have the same name as the spinal nerve (e.g., the
T12 dorsal root ganglion). The cell soma of the ventral root axons are located in the ventral part of the spinal
cord--motoneurons and “preganglionic autonomic neurons.” (Preganglionic neurons will discussed later.)
*Learn the following orientation terms: anterior, posterior, rostral, caudal, dorsal, ventral, medial, lateral, proximal, distal,
ipsilateral, contralateral.
(p. 83, Table 4.1 in your text)
*Learn the following planes of section through the spinal cord and brain: coronal (frontal) section, saggital section,
horizontal section, transverse section (cross section). – (p. 83, Figure 4.2 in your text)
PSB 2000
Class #6: Thurs, 25 Jan 2007
(Class #7 on Tues 30 Jam 2007 is EXAM # 1)
GROSS ANATOMY-part 2Y
I. SUBDIVISIONS OF THE BRAIN
MIDBRAIN
FOREBRAIN
telencephalon
diencephalon
mesencephal
basal ganglia
internal capsule
paleocortex
neocortex
epithalamus
thalamus
subthalamus
hypothalamus
= midbrain
1st
2nd
tectum
tegmentum
3rd, 4th
HINDBRAIN
cerebellum
pons
medulla
--associated with the
cerebellum via the
“cerebellar peduncles”
Dorsal part is sensory
Ventral part is motor
4th, 5th, 6th, 7th, 8th
9th, 10th, 11th 12th
grey areas = “brainstem”
II. ASSOCIATION WITH CRANIAL NERVES
Each of the subdivisions of the brainstem receives input from or sends output through one or
more of the cranial nerves, a situation which has functional implications for that subdivision.
Memorizing the functions of the cranial nerves will help you learn this (Table 4.4, p. 88). Here is some
room for notes from class lectures:
MEDULLA
PONS
MIDBRAIN
DIENCEPHALON
III. TELENCEPHALON
A. Basal ganglia: embedded in the internal capsule-motor functions
B. Internal capsule: axons conveying information to and from the cerebral cortex
C. Cerebral cortex: folded up to increase surface area (sulcus or fissure=base;
gyrus=top of the fold). There are two main types of cerebral cortex:
● paleocortex: 3-4 layers: “limbic cortex”: hippocampus, amygdala, cingulate gyrusclosely associated with the hypothalamus in the diencephalon
● neocortex: 6 layers: 4 lobes:
FRONTAL
Primary motor ctx; eye movement;
“Executive” functions;
Speech:Broca’s area-left side.
Olfaction: associated with paleocortex
PARIETAL
OCCIPITAL
TEMPORAL
Primary
somatosensory cortex
Vision
Audition;
Memory (buried in hippocampus);
Speech (Wernike’s area-left side)
PSB 2000
Class #6: Thurs, 25 Jan 2007
(Class #7 on Tues 30 Jam 2007 is EXAM # 1)
Here are three pages of diagrams that will be useful during
lectures in Classes #6 & 7, GROSS ANATOMY, Part 2:
PSB 2000
Class #6: Thurs, 25 Jan 2007
(Class #7 on Tues 30 Jam 2007 is EXAM # 1)
PSB 2000
Class #6: Thurs, 25 Jan 2007
(Class #7 on Tues 30 Jam 2007 is EXAM # 1)
PSB 2000
Class #8: Thurs, 1 Feb 2007
(Class #7 on Tues, 30 Jan was Exam # 1)
EETHICS AND METHODS OF NEUROSCIENCE RESEARCHH
I. FACTORS ASSOCIATED WITH THE USE OF ANIMALS IN RESEARCH
A. Respect for the welfare of animals is:
● very important
● strictly regulated—by federal law, Nat Institutes of Health (NIH) Also: granting
organizations, professional research societies, scientific journals)
● strictly monitored--by local Animal Care and Use Committee (ACUC) and federal
government (US Dept. of Agriculture),
● strictly enforced—ACUC, NIH, USDA
ACUC: minimal membership
B. Before research can be done:
● training or evidence of training required
● literature review must be done
● ACUC must give approval
● for funding: government (NIH, etc) review #1
● funding: government review #2
1. community ‘lay’ person
(non- scientist, non-academic)
2. veterinarian
3. scientist who works with animals
4. another academic who does not
work with animals
C. During research:
● continued training
● site visits (often unannounced): local ACUC committee; USDA; sometimes NIH
D. Publishing results: All journals have ethical standards that must be met—usually 3 reviews!
II. METHODS USED IN NEUROSCIENCE RESEARCH (both humans and nonhuman animals)---All methods have limitations; best approach is combinations.
A. Anatomical: (What is its structure? What does it look like?)—subcellular to whole brain):
1. Terms: ●cytoarchitecture (how cells are grouped) special stains, radioactivity,
●histochemistry (makes molecules visible) fluorescent dyes
2. Techniques: electron microscopy; light microscopy; confocal microscopy; CAT scans; MRI
3. Important aspects: ● orientation (3 planes, brain atlas, 3-D maps); ● stereotaxic device
4. “Neuronavigation” and Tracing neural connections
B. Functional:
1. Genetisc, Molecular Biology; Neurochemistry
2. Electrophysiological: (how electrical activity relates to function)
a. direct devices: ●oscilloscope (measures voltage changes with time);
●electrodes: microelectrode—single neuron, ‘patch’ of membrane;
macroelectrode---regional activity; EEG
MEG (magnetoencephalography; whole brain)
b. indirect: ●PET--positron emission tomography—decay of injected or inhaled
radioactive elements (133Xenon-inhaled; 11C, 18F, 15O-injected);
●fMRI--functional MRI-- magnetic properties of hemoglobin after O2 release
3. Behavioral:
a. Lesion/Ablation: destroy an area of brain, then measure behavioral change
b. Stimulation: artifically activate an area, then measure behavior elicited
c. experimentally, both a and b have serious interpretative problems for both positive and
negative results; controls are therefore very important.
PSB 2000
Class #9: Tues, 6 Feb 2007
SENSORY MECHANISMS
I. GENERAL ASPECTS OF SENSATION AND PERCEPTION
A. Transduction: the process by which sensory receptors change stimulus energy  action potentials
B. Receptors: types (mechanical, chemical thermal); sources (telereceptors-distance; exteroceptors-on
body; proprioceptors-muscles, joints, vestibular apparatus; interoceptors-internal organs)
C. Adequate stimulus: That stimulus to which a particular sensory receptor is normally AND most
efficiently responsive.
C. Information necessary for perception: Modality, Intensity, Position, Timing
“Law of specific nerve energies” (Müller in 1826): Different perceptual qualities of the stimulus
world are produced by activity in different neurons. In other words, matter how the neurons are
activated the perception produced is the same
D. Relationship between stimulus and perception: Sensations and perceptions are NOT copies of physical
stimuli. The CNS constructs our perceptions, using its ability to integrate, modulate, process, and
control stimulus information.
II. “CHEMOSENSES” (smell = olfaction, taste = gustation)
SMELL
FUNCTION
RECEPTORS
ADEQUATE
STIMULUS
SENSITIVITY
SUBMODALITIES
SUBMODALITY
CODING
AFFERENT
NERVES
MAIN CNS
ROUTES
TASTE
●long distance; ●test environment
(foraging, communication; ● strong
affect
● contact sense; ●test food; ●control
intake; ● begin digestive process
●telereceptors; ● in olfactory mucosa
of nose; ●like a dendrite with cilia;
●primary sense cell; ●~60-day life
cycle; ●>1,000 types
●exteroceptors; ●on tongue; ●made up of
papillae (10, front – 300, back) “taste buds”;
●each bud has 20-50 receptor cells:
●secondary sense cell; 10-day life cycle; ● 4
or possibly more types
molecules in air (mostly organic;
Molecules in fluid (organic and
dissolve in mucous at receptor
inorganic)
surface
VERY high (107 mol/ml (102 – 103 Less sensitive: 1016 molecules/ml
in some species!)
●Thousands,
● sweet: front tongue (fungiform papillae)- G prot, Ca++ open
(foliate
poorly defined
● sour: side (front) tongue K+ chan. close
papillae)
●Many theories
● salty: side (back) Na+ chan. open
● bitter, back of tongue, K+close, 2nd mess (circumvallate papil.)
● unami (MSG)? carbohydrates?, glutamate?
Spatiotemporal pattern in CNS
Which peripheral receptor?
● Ist cranial n. (olfactory n.)
● some in Vth n. (trigeminal n.)
VIIth (facial n., chorda tympani branch — front of tongue)
IXth (glossopharyngeal n., lingual br. —back of tongue)
Xth (vagus n., only a few, ---palate, epiglottis)
Ist n.  olfactory bulb (mitral cells,
glomeruli)  paleocortex (●amygdala 
hypothalamus; ●enterorhinal ctx 
hippocampus; ●pyriform cortex
hypothalamus & orbitofrontal cortex)
VIIth, IXth, Xth  medulla (solitary n.) 
pons (parabrachial n.)  thalamus
(VPMp)  frontal/parietal lobes of
neocortex  orbitofrontal cortex,
amygdala, hypothalamus, basal forbrain
PSB 2000
Class #10: Thurs, 8 Feb 2007
SOMATIC AND VISCERAL SENSATION
FUNCTION
 Provides information about:
--our immediate environments: external-skin; internal-viscera (=internal organs)
--our body position (for ‘kinesthesia’ and posture): muscles & joints
 Important for: protection, warning, social communication
 Involves varying amounts of affect
RECEPTORS
Located all over and inside the body (skin, muscles, tendons, joints, ligaments, viscera
Many specializations: i.e., many different types
Cell bodies located in dorsal root ganglia or trigeminal ganglion: pseudounipolar cells
Axons:
LARGE MYELINATED
SMALL-- little myelin
SMALL--unmyelinated
‘Aβ’ fibers
‘Aδ’ fibers;
‘C’ fibers
fast conduction
slow condution
very slow conduction
Receptive fields can be very large → tiny
The timing of responses can be: (a) rapidly adapting; (b) slowly adapting-stimulus bound;
(c) slowly adapting with afterdischarge.
A
B
C
| |
| | ||||||||
| | ||||||||||||||||||||
response→| | |||
stimulus→
ADEQUATE
STIMULI
 mechanical: pressure, tension
 chemical: CO2, O2, many other molecules (e.g., inflammatory agents)
 thermal: high temperature, moderately high temp, low temp, very low temp
 very high to
almost insensitive
(requires very little stimulation)
(requires very intense stim.)
“low threshold”
“nociceptors”
 can change! That is, they can become desensitized or hypersensitized
 hard to categorize---many?—touch, temperature, pain, itch, tickle, vibration
SUBMODALITIES
roughness, wetness, etc???
 all have varying degrees of affect
 varying precision (e.g., stomachache vs Braille reading)
 some not conscious (e.g., blood pressure, posture)
SUBMODALITY
It is almost impossible to relate the different perceptual submodalities to
CODING
specific receptors, but there have been attempts: for example,--SENSITIVITY
Nociceptors  pain
Low threshold mechanoreceptors  touch
AFFERENT
NERVES
(topographically
organized)
We shall see the problems
with this idea later on !
 from skin and muscle—well ordered somatotopy
--via spinal nerves (cervical-8; thoracic-12; lumbar-5; sacral-5, coccyxgeal-1)
--concept of DERMATOME: The area of skin innervated by sensory fibers in a single
spinal nerve. (Thus, we speak of the C8 dermatome, the T12 dermatome, etc…; see
next page)
 from viscera—somatotopy not as well ordered
--via nerves of autonomic n.s. (Fig 4.6—p.86 in your text)
--we will discuss the parasympathetic and sympathetic systems in class (reread
pgs 85-87 in your text)
PSB 2000
DERMATOMES
Class #10: Thurs, 8 Feb 2007
PSB 2000
Class #11: Tues, 13 Feb 2007
TOUCH and PAIN: CNS mechanisms - From conceptualization to therapy
There are TWO ways of conceptualizing how the nervous system creates the
perceptions of touch and pain
Traditional “pathway” conceptualization
This view is misleading.
This diagram is similar to the one that is provided in most modern textbooks to illustrate so-called “pain pathways” and
“touch pathways.” It is important that we begin with this diagram so that we can then discuss better alternatives.
•• •
• •••• •
• ••
•
A new view: DYNAMIC DISTRIBUTED SYSTEM SYSTEMS
This view fits the data better because:
…it takes into consideration:
(1) ..convergence and divergence of
information flow
(2) ..neural plasticity (learning over
the lifespan).
(3) ...that we cannot equate a
perception with a sensory
receptor or a pathway
 example: phantom limbs.
 brain imaging data
PSB 2000
Class #11: Tues, 13 Feb 2007
PSB 2000
Class #11 (cont’d): Tues, 13 Feb 2007
TREATING PAIN
A growing list of therapies for pain1
DRUGS
Primary analgesics
NSAIDS
acetaminophen
opioids
Other analgesics
-2 agonists
 adrenergic antagonists
antidepressants
anticonvulsants
antiarrhythmics
calcium channel blockers
cannabinoids
corticosteroids
COX-2 inhibitors
GABAB agonists
serotonin agonists
nitric oxide
Adjuvants
antihistamines
laxatives
neuroleptics
phenothiazines
Routes
topical, transdermal, oral
buccal, sublingual, intranasal
vaginal, rectal
inhalation
intramuscular, intraperitoneal
intravenous
epidural, intrathecal
intraventricular
SOMATIC
INTERVENTIONS
SITUATIONAL
APPROACHES
Simple
Clinician
education
attitude
clinical setting and arrangement
heat/cold
exercise
massage
vibration
relaxation
Minimally invasive
physical therapy
traction
manipulation
ultrasound
TENS
acupuncture
local anesthetics
Invasive
radiation therapy
dorsal column stimulation
nerve blocks
neurectomy
local ganglion blocks
sympathectomy
rhizotomy
DREZ lesions
punctate midline myelotomy
limited myelotomy
commissural myelotomy
cordotomy
brain stimulation
brain lesions
1
January 2007
Self
education
meditation
Diet, herbal supplements
art, music, poetry, performing arts
sports, gardening, hobbies
humor, virtual reality
aroma therapy
religion
pets
Interactive
hypnosis
biofeedback
support groups
advocacy groups
networking
self-help groups
Structured settings
group therapy
family counseling
job counseling
cognitive therapy
behavioral therapy
psychotherapy
multidisciplinary clinic
hospice
PSB 2000
Class #12&13: Thus & Tues, 15 & 20 Feb 2007
(class #14 on Thurs 23 Feb is Exam #2)
AUDITION
FUNCTION
STIMULI
 RECEPTOR
APPARATUS
To provide us with information about the environment that is distant from us. For
communication between individuals.
Sound pressure waves: alternating “compression” and “rarefaction” of air. The waves have an
AMPLITUDE and FREQUENCY. Amplitude is measured in ‘bels’ (or decibels-dB—10ths of
bels). A bel is actually a psychophysical measure that is related to a reference “sound” intensity. 0
dB is about level of softest sound an average person can hear at 1000 cycles/sec = 0.0002
dynes/cm2 (a dyne is a physical measure of force; 1dyne = 1gm/cm/sec). dB = 20 log observed
force/reference force. [examples: 130dB is max level before tissue damage occurs (stand behind a
jet airplane). 20dB is soft whisper at ~10ft.]
Outer ear through middle ear: Sound pressure waves are funneled via the pinna (external ear)
through the external auditory canal to the eardrum (tympanic membrane), then through the bones of
the middle ear (malleus-hammer; incus-anvil; stapes-stirrup) to the OVAL window of the cochlea.
The tymp. Membrane is 16X size of the oval window! Thus, the middle ear transforms low energy
sound waves to smaller amplitude, but much more forceful displacements of the stapes to move
fluid in the cochlea. (The middle ear lies between the tymp. membrane and the oval window.)
Cochlea: Coiled structure filled with fluid & divided into three compartments (see text). The
receptor organ is in the central compartment, & is called the “organ of Corti” (composed of basilar
membrane, hair cells, tectorial membrane). Cochlear fluid is displaced by movements of stapes against oval
window, with pressure being released at the ROUND window. Thus, sound pressure waves are
transmitted as vibrations of the fluid surrounding the organ of Corti.
The base end of the cochlea (stapes end) is stiffer and can transmit higher frequencies than the
apical end, which is floppier and transmits lower frequencies. We lose some stiffness with age—
therefore we lose ability to hear high frequency components of sound waves.
Hair cells: cilia-like structures anchored in the basilar membrane, with tips held in place in the
tectorial membrane. Flexing of the basilar/tectorial membranes moves hair cells and changes the
flow of K+ and Ca++ ions to produce action potentials in cochlear nerve fibers.
AFFERENT NERVES
Fibers in the auditory (8th cranial) nerve. The cell bodies of these axons are in the “spiral
receptopically organized
ganglion” which runs along the length of and adjacent to the cochlea.
RECEPTORS
(thus, “tonotopically” organized?)
AIN ROUTES
THROUGH CNS
SUBMODALITIES
AND THEIR
CODING
Auditory nerve  ipsilateral cochlear nucleus (in medulla/pons)  contralateral superior
olive (pons)  inferior colliculus (midbrain)  medial geniculate nucleus (in thalamus)
 “auditory” cortex in temporal lobe. In other words, the cochlear n. receives input from
the ipsilateral ear, but most of the information is then relayed to the contralateral superior
olive.
 Loudness: related to the amplitude of the sound wave, BUT depends on frequency too.
Loudness is coded mainly by the # neural fibers activated (not their frequency) (We will
discuss audiograms and hearing loss in class.)
 Pitch: related to both the frequency of firing of receptor fibers and place (i.e., which
neurons). From 15  100hZ: frequency code. From 100  4,000Hz: volley coding and
place coding (i.e., receptor location on cochlea). (We will discuss cochlear implants in
class.) NOTE: Your book states that place coding occurs only at frequencies >4,00Hz.
This conclusion is now known to be wrong, mainly because of cochlear implant success.
 Direction: The brain compares input from two ears, which arrives at different parts of the
sound wave (phase) and with different amplitudes.
 Distance: Depends on sound wave composition. [Higher frequencies are lost faster as
they travel towards the ear. Therefore the closer the sound, the more the sound contains
higher frequency components.
PSB 2000
Class #11: Tues, 13 Feb 2007