Transcript Brain

Neurons
Chapter 3
Dendrites
Extensions from the
neuron cell body that
take information TO
the cell body.
Cell Body
Also called the
soma; the part of the
cell that contains the
nucleus.
Nucleus
Part of the neuron
that contains
chromosomes
(genetic material)
Axon
The part of the
neuron that takes
information AWAY
from the cell body.
Myelin
Fatty substance that
surrounds some axons.
Speeds up conduction
velocity of action
potentials.
Node of Ranvier
Gaps in the
myelination of axons.
Synaptic Terminal
The end of the axon
containing vesicles
with
neurotransmitters.
INFORMATION PROCESS
DUH, the SAT
D=dendrites
S=soma
A=axon
T=terminals
Neurotransmitters
Neurotransmitters
(chemicals) released
from the sending
neuron travel across
the synapse and bind
to receptor sites on the
receiving neuron,
thereby influencing it
to generate an action
potential.
Neurotransmitters (p.58)
Nervous System
Central
Nervous
System
(CNS)
Peripheral
Nervous
System
(PNS)
Nervous System
System of nerves involved
in thought processes,
heartbeat, visual-motor
coordination, etc…
Central and Peripheral
systems
Central Nervous System
Consists of the brain and
spinal cord
Spinal Cord
A column of nerves within
the spine that transmits
messages from sensory
receptors to the brain and
from the brain to muscles
and glands throughout the
body.
Spinal Cord
Spinal Reflexes: an unlearned response to
a stimulus that may involve only two
neurons
a) Sensory (afferent) neuron-to cortex
b) Motor (efferent) neuron-away
SAME
You are *affected* by a situation, you *effect*
change on someone else.
Blink, swallow,knee-jerk, sexual
responses, urinating, etc…
Brain
Hindbrain(lower part of brain):
Medulla-heart rate, blood
pressure, respiration
Pons-respiration, attention,
sleep, dreaming
Cerebellum-muscle
coordination and balance
Brain
Reticular Activating System (RAS):
Vital in the functions of
attention, sleep, and arousal
Injury to RAS can cause
comatose
Filtering (awakened by infant)
Brain
Forebrain (front most part):
1). Thalamus-center of brain
Relay station for sensory stimulation
Relays sensory input from the eyes to the
visual areas of the cerebral cortex
Functions of sleep and attention
Brain
Forebrain (front most part):
2). Hypothalamus-beneath thalamus and
above pituitary gland
Body temperature, motivation, emotion
Involved in hunger, thirst, sexual
behavior, caring for offspring, aggression
4 F’s=feeding, fighting, fleeting,
fornicating  (pleasure/reward center)
Brain
Forebrain (front most part):
3). Limbic system-inner edge of cerebrum
and in mammals only
Memory, emotion, drives of hunger, sex,
aggression
Amygdala-facilitates aggressive
responses,fear
AHH=hypothalamus, amygdala,
hippocampus
Brain
Forebrain (front most part):
4). Basil ganglia-between
thalamus and cerebrum
Control of movements and
coordination
Dopamine produceddegeneration can cause
Parkinson’s disease
Brain
Forebrain (front most part):
5). Cerebrum-crowning glory of brain
Cerebral cortex-the wrinkled and
convoluted surface
Consists of two hemispheres
Corpus Callosum-connects the two
hemispheres
Peripheral Nervous System
Consists of sensory and motor
neurons that transmit messages
to and from the central nervous
system
Without the PNS, our brains
would be isolated from the world
Somatic and Autonomic NS
Somatic Nervous System
Connects the central
nervous system with sensory
receptors, skeletal muscles,
and the surface of the body
Ex:raising hand, winking,
running, posture, balance
Autonomic Nervous System
Regulates the glands and the
muscles of internal organs
Heartbeat, respiration,
digestion, dilation of the pupils
of the eyes
Can occur automatically
Sympathetic & Parasympathetic
Autonomic Nervous System
Sympathetic- most active
during processes that
involve the spending of body
energy from stored reserves
“Fight-or-Flight”
Autonomic Nervous System
Parasympathetic- most active
during processes that
replenish reserves of energy
(eating)
Calms “parachute)
Autonomic Nervous System
Sympathetic-accelerates the heart rate
-inhibits digestion
Parasympathetic-
-decelerates the heart rate
-stimulates digestive processes
Lobes of the Brain
Frontal Lobe
Located in front of the
central sulcus
Concerned with reasoning,
planning, parts of speech,
movement (motor cortex),
emotions, and problemsolving
Parietal Lobe
Located behind the
central sulcus
Concerned with
perception of stimuli
related to touch, pressure,
temperature, pain
Temporal Lobe
Located below the lateral
fissure
Concerned with perception
and recognition of auditory
stimuli (hearing) and memory
(hippocampus)
Occipital Lobe
Located at the back of the
brain, behind the parietal
lobe and temporal lobe
 Concerned with many
aspects of vision
Structure of the Cortex
Each brain hemisphere
is divided into four
lobes that are separated
by prominent fissures.
These lobes are the
frontal lobe (forehead),
parietal lobe (top to rear
head), occipital lobe
(back head) and
temporal lobe (side of
head).
http://bungelab.berkeley.edu/KidsCorner/kids
corner/games.html
Brain Structures
Cerebral Cortex
Thought
Voluntary movement
Language
Reasoning
Perception
The Cerebral Cortex
The intricate fabric of interconnected neural cells
that covers the cerebral hemispheres. It is the
body’s ultimate control and information processing
center.
Cerebellum
Movement
Balance
Posture
Cerebellum
The “little brain”
attached to the
rear of the
brainstem. It
helps coordinate
voluntary
movements and
balance.
Brain Stem
Breathing
Heart Rate
Blood Pressure
Older Brain Structures
The Brainstem is the oldest part of the
brain, beginning where the spinal
cord swells and enters the skull. It is
responsible for automatic survival
functions.
Brain Stem
The Medulla [muhDUL-uh] is the base of
the brainstem that
controls heartbeat and
breathing.
Reticular Formation is
a nerve network in the
brainstem that plays
an important role in
controlling arousal.
Hypothalamus
Body temperature
Emotions
Hunger
Thirst
Circadian rhythms
4 F’s
Hypothalamus
The Hypothalamus lies
below (hypo) the
thalamus. It directs
several maintenance
activities like eating,
drinking, body
temperature, and
control of emotions. It
helps govern the
endocrine system via
the pituitary gland.
Reward Center
Sanjiv Talwar, SUNY Downstate
Rats cross an electrified
grid for self-stimulation
when electrodes are
placed in the reward
(hypothalamus) center
(top picture). When the
limbic system is
manipulated, a rat will
navigate fields or climb
up a tree (bottom
picture).
Thalamus
Sensory processing
Movement
Brain Stem
The Thalamus [THALuh-muss] is the brain’s
sensory switchboard,
located on top of the
brainstem. It directs
messages to the
sensory areas in the
cortex and transmits
replies to the
cerebellum and
medulla.
Limbic System
Emotions
Memory
The Limbic System
The Limbic System is a
doughnut-shaped
system of neural
structures at the border
of the brainstem and
cerebrum, associated
with emotions such as
fear, aggression and
drives for food and sex.
It includes the
hippocampus, amygdala,
Amygdala
The Amygdala
[ah-MIG-dahla] consists of
two almondshaped neural
clusters linked
to the emotions
of fear and
anger.
Hippocampus
Learning
Memory
Basal Ganglia
Movement
Midbrain
Vision
Audition
Eye movement
Body Movement
The Brain
A brain lesion
experimentally
destroys brain
tissue to study
animal
behaviors after
such
destruction.
Techniques to Study the
Brain
Hubel (1990)
Clinical Observation
Clinical observations have shed light on a number of
brain disorders. Alterations in brain morphology due
to neurological and psychiatric diseases are now being
catalogued.
Tom Landers/ Boston Globe
Electroencephalogram (EEG)
An amplified recording of the electrical
waves sweeping across the brain’s
surface, measured by electrodes placed
on the scalp.
PET Scan
Courtesy of National Brookhaven National Laboratories
PET (positron
emission tomography)
Scan is a visual
display of brain
activity that detects a
radioactive form of
glucose while the
brain performs a given
task.
MRI Scan
MRI (magnetic resonance
imaging) uses magnetic
fields and radio waves to
produce computergenerated images that
distinguish among
different types of brain
tissue. Top images show
ventricular enlargement in
a schizophrenic patient.
Bottom image shows brain
regions when a
participants lies.
Both photos from Daniel Weinberger, M.D., CBDB, NIMH
James Salzano/ Salzano Photo
Lucy Reading/ Lucy Illustrations
Auditory Function
The functional MRI scan
shows the auditory
cortex is active in
patients who hallucinate.
Association Areas
More intelligent animals have increased
“uncommitted” or association areas of the cortex.
The Brain’s Plasticity
The brain is sculpted by our
genes but also by our
experiences.
Plasticity refers to the brain’s
ability to modify itself after some
type of injury or illness.
Our Divided Brain
Our brain is divided into two
hemispheres.
The left hemisphere
processes reading, writing,
speaking, mathematics, and
comprehension skills. In the
1960s, it was termed as the
dominant brain.
Splitting the Brain
Martin M. Rother
Courtesy of Terence Williams, University of Iowa
A procedure in which the two hemispheres of the
brain are isolated by cutting the connecting
fibers (mainly those of the corpus callosum)
between them.Corpus Callosum
Split Brain Patients
With the corpus callosum severed, objects
(apple) presented in the right visual field can be
named. Objects (pencil) in the left visual field
cannot.
Divided Consciousness
Try This!
Try drawing one shape with your left hand and
one with your right hand, simultaneously.
BBC
Non-Split Brains
People with intact brains also show
left-right hemispheric differences in
mental abilities.
A number of brain scan studies show
normal individuals engage their right
brain when completing a perceptual
task and their left brain when
carrying out a linguistic task.
Brain Organization & Handedness
Is handedness inherited?
Yes. Archival and historic
studies, as well as modern
medical studies, show that
the right hand is preferred.
This suggests genes and/or
prenatal factors influence
handedness.
Is it Alright to be Left Handed?
Being left handed is difficult in a righthanded world.
Is it Alright to be Left Handed?
The percentage of left-handed individuals
decreases sharply in samples of older people
(Coren, 1993).
Language Functions
Aphasia
Damage to the left part of
the brain in the cerebral
cortex
Definition:impaired ability to
comprehend or express
oneself through language
Broca’s Area
Prevents a person from
producing speech
Person can understand
language
Words are not properly
formed
Speech is slow and slurred
Wernicke’s Area
Loss of ability to understand
language
Person can speak clearly,
but the words that are put
together make no sense.
“Word salad” because it
appears that the words are
all mixed up like the
vegetables in a salad
Language
Aphasia is an impairment of language,
usually caused by left hemisphere damage
either to Broca’s area (impaired speaking) or
to Wernicke’s area (impaired
understanding).
Specialization & Integration
Brain activity when hearing, seeing, and speaking
words
Journal
Would you rather have Broca’s
aphasia or Wernicke’s
aphasia? Why?
Alzheimer’s Disease
Alzheimer’s Disease
A progressive form of mental
deterioration that may affect
as many as 4 million
Americans
Connected with aging but it
is a disease and NOT part of
a normal aging process
Alzheimer’s Disease
Characterized by
progressive deterioration in
mental processes such as
memory, language, and
problem solving
Seriously impairs vocational
and social functioning
Alzheimer’s Disease
Memory loss:
difficult to recall basic info (zip codes,
telephone #s, names of grandchildren,
addresses)
Large gaps in memory for recent events
May fail to recognize familiar people or
forget their names
Alzheimer’s Disease
Continue..
May not recognize themselves in the
mirror
Unable to recall names of their school,
birthplace, parents
No longer able to speak in full sentences
and limit their verbal responses to a few
words
Alzheimer’s Disease
Subtle personality changes:
signs of withdrawal or irritability
May need assistance to manage
everyday tasks (selecting
clothes to wear)
Difficulties in personal
functioning (using bathroom and
washing themselves)
Alzheimer’s Disease
May pace or fidget or display
aggressive behavior (yelling,
hitting, throwing)
May wander off and not be able
to find their way back
1 in 3 show signs of
hallucinations or delusions
Alzheimer’s Disease
Severe cases:
People become helplessunable to communicate or
walk and require help in
toileting and feeding.
Alzheimer’s Disease
Discovered by German
physician Alois Alzheimer
Found brain abnormalities in
a 56-year old woman with
dementia
Brain Abnormalities
1) Plaques: destroy brain
tissues which leads to loss of
memory function, confusion,
and other symptoms
2) Tangles: twisted bundles
of nerve cells
Biochemical
Reduced levels of acetylcholine
(ACh): reflect loss of brain cells
and can lead to brain trauma,
aluminum poisoning
Reduced metabolic rates
Negative correlation between
cognitive performance and
metabolic rate
Genetic Transmission
90% of people who inherit a key
gene from both parents contract
Alzheimer’s disease by the age
of 75
Chemotherapy is used to
heighten ACh levels
Researchers are hopeful that
genetic studies may lead to
effective medications