Main Idea:
• There are many parts in the human brain that work together
to coordinate movement and stimulate thinking and
emotions.
The Brain
Techniques to Study the Brain
• A brain lesion
experimentally destroys
brain tissue to study
animal behaviors after
such destruction.
• Remember, the
hippocampus was
removed from rats at
various times after
learning a maze.
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
Studying the Living Human Brain
• Animal studies and clinical observations are useful, but often,
such as when we need to diagnose or treat illness, we want to
know what is happening inside the brain of a living human.
• For this we have:
• EEG: Electroencephalogram
• MRI: Magnetic resonance imaging
• PET Scan: Positron emission tomography
• CT Scan (or CAT Scan): Computerized Tomography
Electroencephalogram (EEG)
An amplified recording of the electrical waves
sweeping across the brain’s surface, measured by
electrodes placed on the scalp.
AJ Photo/ Photo Researchers, Inc.
MRI: Magnetic Resonance Imaging
• MRI uses magnetic fields and radio waves to produce
computer-generated images that distinguish among different
types of brain tissue.
•Top images show
ventricular enlargement in
a schizophrenic patient.
Both photos from Daniel Weinberger, M.D., CBDB, NIMH
•Bottom image shows brain
regions when a
participants lies.
James Salzano/ Salzano Photo
Lucy Reading/ Lucy Illustrations
PET Scan: Positron Emission Tomography
• Detects gamma rays
emitted by a radioactive
form of glucose while the
brain performs a given
task.
Courtesy of National Brookhaven National Laboratories
• PET Scan is a visual
display of brain activity
CT Scan: Computerized Tomography
• X-ray rotates around head.
• May be done with or without
contrasting dye.
• Images taken from different
angles are assembled into 3-D
image
• CT scan produces much more
detailed image than x-ray of
bone and soft tissue
The Brain
The Brain
Brain stem
Cerebrum
Cerebellum
Cerebrum
Cerebellum
Brain Stem
The Brain Stem:
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.
Brainstem
Thalamus
The Thalamus [THAL-uhmuss] is the brain’s sensory
switchboard, located on top
of the brainstem.
1.
2.
3.
4.
To
cerebellum
It directs messages to the
sensory areas in the cortex
and transmits replies to the
cerebellum and medulla.
To
medulla
Pons
The Pons plays a role in
muscle coordination.
Pons
Reticular Formation
•Reticular Formation is a
nerve network in the
brainstem that plays an
important role in controlling
arousal.
• Damage to this causes a
disorder called narcolepsy in
which a person falls asleep
suddenly during the daytime
and cannot resist the sleep.
Medulla
The Medulla [muhDUL-uh] is the base of
the brainstem that
controls heartbeat and
breathing.
Cerebellum
• The “little brain”
attached to the rear of
the brainstem.
• It helps coordinate
voluntary movements
and balance.
• Implicit (procedural)
memory.
The Limbic System
• The Limbic System
is a doughnutshaped 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.
Amygdala
The Amygdala [ah-MIGdah-la] consists of two lima
bean-sized neural clusters
linked to the emotions of
fear and anger.
Hypothalamus
• Hypothalamus lies below (hypo) the
thalamus.
• Directs maintenance activities like
eating, drinking, body temperature,
and control of emotions.
• It stimulates or inhibits pituitary
gland  other endocrine glands
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).
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.
Structure of the Cortex
Each brain hemisphere is divided into four lobes
Functions of the Cortex
• The Motor Cortex is the area at the rear of the frontal
lobes that control voluntary movements.
• The Sensory Cortex (parietal cortex) receives
information from skin surface and sense organs.
Visual Function
Visual Function
• Notice the visual
cortex is located in the
occipital lobe.
Courtesy of V.P. Clark, K. Keill, J. Ma.
Maisog, S. Courtney, L.G.
Ungerleider, and J.V. Haxby,
National Institute of Mental Health
• The functional MRI
scan shows the visual
cortex is active as the
subject looks at faces.
Auditory Function
• The auditory cortex contains distinct subregions
that are important for decoding complex sound.
• Auditory cortex is in the temporal lobe.
5. The motor cortex is involved
in sensory–motor feedback,
in controlling movements
needed to produce music
using an instrument.
5
3
2. information travels
through the
brainstem and
midbrain to the
1
auditory cortex.
1. Sound waves enter
ear, and are turned
into neural
impulses by the
inner ear
2
4
4. The frontal
lobe is
involved in
emotional
evaluation.
3. information from the
auditory cortex interacts with
many other brain areas,
especially the frontal lobe, for
memory formation and
interpretation.
Auditory Hallucinations
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.
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
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 types 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
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.
Martin M. Rother
Courtesy of Terence Williams, University of Iowa
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.
Try This!
Try drawing one shape with your left hand and
one with your right hand, simultaneously.
BBC