Transcript An accident caused a tamping iron to go through his head

Chapter 2
III. A Phineas Gage
 Level headed, calm foreman of a railroad crew (1848).
 An accident caused a tamping iron to go through his
head. (One of the next slides shows the path)
 The injury severed the connections between his limbic
system and frontal cortex. He survived
III. A – cont…
 This caused his personality to totally change- he
became volatile
 This injury allowed us to understand the brain before
technology was available.
 ( I will show you a video next week about him.)
Phineas
Gage
III. B. Paul Broca
 Performed an autopsy on the brain of a patient
known as Tan (because that is all he could say)
There was no physical reason for his lack of
speech.
 Broca found an area in the brain that showed
deterioration in the frontal lobe of the left
cerebral hemisphere
 Now called Broca’s area- damage to this area
cause expressive aphasia (meaning person can’t
talk- think about stroke victims)
IV. Producing lesions
 To lesion means to damage part of the
brain.
 Sometimes they have to surgically
remove brain tissue or sever a brain
connection to help a person.
 This has allowed doctors to study brain
function.
VII- EEG
 Allows us to study the brain’s electrical
activity via electrodes placed on the scalp.
 Used to study the brain during different
states of arousal (sleep studies use them)
 It also can be used to detect abnormalities.
 The next two slides show an EEG- the 2nd
one is one they are using on a young child
to detect a hearing impairment.
VIII. A. CAT SCANS
 1.
Creates a …. That shows a two dimensional
view of the brain.
 2. Procedure… of a contrast dye.
CAT SCANS show the structure of the brain.
Next slide shows a CAT scan of someone with
Broca’s Aphasia
B. MRI
 Ignore the start of your notes and write
this
 It uses the spin of hydrogen in water
cells to read the brain (or body part)
 It produces more detailed images then
Xrays or CAT Scans
 Useless information here… But if you
have a pacemaker you can’t have a MRI
(THINK BIG MAGNET!!)
MRI
2. fMRI
 Shows more detailed information than PET scans.
 (This isn’t so important to know)
 Figure 5.11
Functional
magnetic
resonance imaging
(fMRI) When the
subject is in the
scanner, the
researchers will be
able to
communicate with
him using an
intercom system
and a visual
projection system.
The image of the
brain depicts, with
colors of the
rainbow, the
amount of blood
flow in each part
of the brain,
which indicates
the amount of
neural activity in
each part.
How to tell a liar- MRI- ignore this
I will talk about it next week
C. PET Scans
 A radioactive isotope is injected into the
person.
 This allows the machine to study glucose and
oxygen changes in an area of the brain.
 This has allowed us to study the functioning of
the brain.
 A PET scan is used in many studies about what
part of the brain is active when you read, talk,
lie, think about specific subjects- the
possibilities are endless!
Pet
scan
Comparison
I. The neuron receives or sends
messages.
2
3.
1.
4.
B. Neurotransmitters
 We need them because there is a space at the
end of the axon (called synaptic cleft or
synapse) and the message has to get to the next
neuron.
 1. Acetylcholine- causes contraction of skeletal
muscles.
 Interference and/or depletion of ACh is
associated with Alzheimer’s disease.
3. GABA
 Inhibits the firing of neurons.
 Valium and anticonvulsant drugs
increase GABA and thus slows the firing
of neurons
4. Dopamine
Influences learning, movement,
emotion and attention.
Lack of relates to Parkinson’s
Excess relates to Schizophrenia
5. Serotonin
Affects mood, hunger, sleep and
arousal.
Undersupply relates to depression
6. Endorphins
They make us happy (to Quote
Legally Blonde)
They are the brain’s own pain
killers
Narcotics such as heroin replace
them- why withdrawal is so
painful
Add in Norepinephrine
The neurotransmitter = of
adrenalin
Controls alertness and arousal
Undersupply related to depression
END HERE!!!!
 The neuron at rest is more negative inside
the cell membrane relative to outside the
membrane. The resting neural membrane
potential is about -70mV.
 The resting potential results from selective
permeability of the membrane, the presence
of electrically charged particles called ions
near the inside and outside surfaces of the
membrane and resulting concentration and
electrical gradients.
Resting potential
 When sufficiently stimulated (to threshold) a net flow
of sodium ions into the cell occurs (along with a
movement of potassium ions out). Polarity is reversed
to +40mV called the action potential.
Glial cells
 (D) A high-power light-
microscopic view of the
cell body, illustrating the
nucleus and the
nucleolus. Note that the
different stains highlight
different aspects of the
neuron.
 Figure 5.6 Axon terminals
This electron micrograph
shows the terminals of many
axons forming synapses on a
portion of the cell body of a
single neuron. Synaptic
vesicles, filled with
neurotransmitter molecules,
reside within the button-like
swelling of each axon
terminal. In the central
nervous system, the cell
bodies and dendrites of
motor neurons and some
interneurons are blanketed
with thousands of such
terminals.
 A synapse =
 A particular terminal button of an axon
 The synaptic cleft
 The receiving portion of another neuron,
gland cell or muscle cell
 Figure 3.05 A. Photomicrograph of a synapse in
action taken with the electron microscope. Vesicles
are releasing their transmitter chemical into the
synaptic cleft. B. Schematic of the process.
 (C) An electron micrographic image of the contacts between an
axon from another neuron and a dendrite, illustrating the
synapse formed by the opposition of the end foot of the axon
and the dendritic spine of the dendrite.
 FIGURE 2.2 The
Parts of a Typical
Neuron The
drawing shows the
location and
function of key
parts of a neuron.
The photograph,
made with the aid
of an electron
microscope,
reveals actual cell
bodies, dendrites,
and axons in a
cluster of neurons.
The green coloring
was added to
provide contrast in
the photograph to
make the neurons
more visible.