The Brain
Module 4
The Biology of Mind
Older Brain Structures
 The Brain Stem
 CLOSE UP: The Tools of Discovery –
Having Our Head Examined
 The Thalamus
 The Reticular Formation
 The Cerebellum
 The Limbic System
The Cerebral Cortex
 Structure of the Cortex
 Functions of the Cortex
 The Brain’s Plasticity
Our Divided Brain
 Splitting the Brain
 Right-Left Differences in the Intact Brain
CLOSE UP: The Tools of Discovery –
Having Our Head Examined
Lesion [LEE-zhuhn]: tissue destruction. A brain
lesion is a naturally or experimentally caused
destruction of brain tissue.
Electroencephalogram (EEG): an amplified
recording of the waves of electrical activity that
sweep across the brain’s surface, measured by
electrodes 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 computer generated images of soft
tissue, showing brain
anatomy.
fMRI (functional MRI):
technique for revealing
bloodflow and, therefore,
brain activity by
comparing successive MRI
scans, showing brain
function.
Both photos from Daniel Weinberger, M.D., CBDB, NIMH
MRI scan of a healthy individual
(left) and a person with
schizophrenia (right)
The Brainstem and the Thalamus
The brainstem, including the pons and medulla, is an
extension of the spinal cord.
The thalamus is attached to the top of the brainstem.
The reticular formation passes through both structures.
Brainstem
Brainstem
The Medulla [muhDUL-uh] is the base of
the brainstem that
controls heartbeat and
breathing.
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Brainstem
Reticular Formation is a
nerve network in the
brainstem that plays an
important role in
controlling arousal.
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Brainstem
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.
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The Brain
 Cerebellum [sehr-uhBELL-um]
 the “little brain”
attached to the rear
of the brainstem
 it helps coordinate
voluntary movement
and balance
The Brain by the Brain
The Brain
The Limbic System
The Limbic System is a
neural system (including
the hippocampus,
amygdala, and
hypothalamus)
located below the
cerebral hemispheres;
associated with emotions
and drives.
Amygdala
The Amygdala [ahMIG-dah-la]
consists of two lima
bean-sized neural
clusters linked to
the emotions of fear
and anger.
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.
Hypothalamus
Reward Center
Rats cross an electrified
grid, accepting painful
shocks, for self-stimulation
when electrodes are
placed in the reward
(hypothalamus) center.
The Cerebral Cortex
 Cerebral Cortex
 the intricate fabric of interconnected
neural cells that covers the cerebral
hemispheres
 the body’s ultimate control and
information processing center
The Cerebral Cortex
The cerebral [seh - REE-bruhl] cortex is the intricate fabric of
interconnected neural cells that covers the cerebral hemispheres.
The body’s ultimate control and information processing center.
The Cerebral Cortex
 Frontal Lobes
 involved in speaking and muscle movements and in making
plans and judgments
 Parietal Lobes
 include the sensory cortex
 Occipital Lobes
 include the visual areas, which receive visual information
from the opposite visual field
 Temporal Lobes
 include the auditory areas
The Cerebral Cortex
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
The functional MRI scan
shows the visual cortex
is active as the subject
looks at a photo.
Courtesy of V.P. Clark, K. Keill, J. Ma.
Maisog, S. Courtney, L.G.
Ungerleider, and J.V. Haxby,
National Institute of Mental Health
Association Areas
More intelligent animals have increased
“uncommitted” or association areas of the cortex.
Neurons in these areas integrate information.
Language: Specialization and
Integration
Brain areas involved in language processing
•
Language: Specialization and
Integration
Aphasia: impairment of language, usually caused by
left-hemisphere damage either to Broca’s area or
Wernicke’s area.
Broca’s area: controls language expression; an area of
the frontal lobe, usually in the left hemisphere,
directs muscle movements involved in speech.
Wernicke’s area: controls language reception; usually
in the left temporal lobe, involved in language
comprehension and expression.
Specialization & Integration
Brain activity when hearing, seeing, and speaking
words
Brain Rules
from John Medina 2008
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Exercise boosts brain power
The human brain evolved, too.
Every brain is wired differently.
We don’t pay attention to boring things.
Repeat to remember.
Remember to repeat.
Sleep well, think well.
Stressed brains don’t learn the same way.
Stimulate more of the senses.
Vision trumps all other senses.
Male and female brains are different.
We are powerful and natural explorers.
Phineas Gage
Gage Page
Brain Reorganization
 Plasticity
 the brain’s capacity for modification, as
evident in brain reorganization following
damage (especially in children) and in
experiments on the effects of experience
on brain development
 Video
Seven tenets of plasticity
 Change can occur only when the brain is in the mood.
 Change strengthens connections between neurons engaged
at the same time.
 Neurons that fire together wire together.
 Initial changes are just temporary.
 Brain plasticity is a two-way street and we can either drive
brain change positively or negatively.
 memory is crucial to learning.
 motivation is a key factor in brain plasticity.
 New skill acquisition is key to plasticity.
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.
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.
Testing the Divided Brain
Try This!
Try drawing one shape with your left hand and
one with your right hand, simultaneously.
BBC
Right-Left Differences in the Intact
Brain
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.
Example of Brain Processing
Read the following slide silently to
yourself
as I read it out loud
Eaxmlpe of Pcrocessnig
The paomnnehil pweor of the hmuan mnid.
Aoccdrnig to a rscheearch sutdy at Cmabrigde Uinervtisy, it
deosn't mttaer in waht oredr the ltteers in a wrod are, the
olny iprmoetnt tihng is that the frist and lsat ltteer be at the
rghit pclae. The rset can be a total mses and you can sitll raed
it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not
raed ervey lteter by istlef, but the wrod as a wlohe.
amzanig huh?