Download The Cerebral Cortex

The Cerebral Cortex
The Evolving Brain
• Different animal
species have many
structures in common,
including a cerebellum
and cortex.
• The cortex is much
larger in mammals
than in species that
evolved earlier, such as
fish and amphibians.
• The cross section of
the human brain shows
how the cerebral cortex
has developed around
and above more
primitive brain
structures.
Areas of the Cortex
• More intelligent animals have increased
"uncommitted" or association areas of the
cortex.
• These vast areas of the brain are responsible
for integrating and acting on information
received and processed by sensory areas.
When it comes to Cortex…
Size DOES Matter
• If flattened, a human
cortex would cover
about four pages of
this book.
• A chimpanzee's
would cover one
page
• a monkey's a
postcard
• a rat's a postage
stamp.
• From Scientific
American, October
1994, p. 102.
Developing
Brain
•Neural tube—beginning of
nervous system develops at 2
weeks after conception
•Neurogenesis—development
of new neurons
Forebrain Structures
Largest Brain Region
with the most complex
structures.
What separates us from
the beasts.
Cortical Specialization
• Localization—notion that different
functions are located in different areas
of the brain
• Lateralization—notion that different
functions are processed primarily on
one side of the brain or the other
Brain has 2 Hemispheres
• Left & Right sides are
separate
• Corpus Callosum : major
pathway between
hemispheres
• Some functions are
‘lateralized’
– language on left
– spacial relations, music on
right
• Lateralization is never
100%
Corpus Callosum
Right
Hemisphere
Left
Hemisphere
Lateralization of the Hemispheres
An Example of
Spacial Relations
Answer: E
Each hemisphere is
divided into 4 lobes
Frontal
Parietal
Occipital
Temporal
Frontal Lobe
•Contains primary motor cortex
•Important in judgment,
planning and sequencing areas
•Controls emotional center of
the brain (limbic system)
•Contains Broca’s area for
speech
•Prefrontal area for working
memory (Short-Term Memory)
– helps you remember what
you just did so you know what
to do next (sequencing)
Frontal
Lobe
Broca’s
Area
Motor
Motor
Cortex
Cortex
Temporal Lobe
•Contains primary auditory cortex –
interprets hearing info
•Inputs are auditory, visual patterns
–speech recognition
–face recognition (Fusiform
Gyrus)
–word recognition
–memory formation
•Outputs to limbic System, Basal
Ganglia, and brainstem
Auditory
Cortex
Temporal
Lobe
Occipital Lobe
• Input from Optic
nerve
• Contains primary
visual cortex
– Makes sense of visual
info
• Sends info to
parietal and
temporal lobes
Occipital
Lobe
Visual
Lobe
Parietal Lobe
•Receives info from multiple
senses
•Contains primary somatosensory
cortex
 your “skin” sense of touch
and temperature.
•Sends info to Frontal lobe to help
in:
• hand-eye coordination
• eye movements
• attention
Somatosensory
Parietal
Cortex
Lobe
Lobes of the Cortex
• Frontal lobe—largest lobe, produces
voluntary muscle movements, involved in
thinking, planning, emotional control
• Temporal lobe—primary receiving area for
auditory information
• Occipital lobe—primary receiving area for
visual information
• Parietal lobe—processes sensory
information from your body information
BOREDOM BUSTER!
Let’s Review with Pinky & The Brain.
Motor
Cortex:
Located at
the back of
the Frontal
Lobe.
The more
precise
movements,
the more
motor
cortex the
part uses
up.
Sensory
Cortex:
Located at
the front of
the Parietal
Lobe.
The more
sensitive
the area, the
more
sensory
cortex it
uses up.
Language and the Brain
• Aphasia—partial or
complete inability to
articulate ideas or
understand language
because of brain injury or
damage
• Broca’s area—plays role in
speech production
• Wernicke’s area—plays
role in understanding and
meaningful speech
Aphasias
• Broca’s Aphasia – Damage to Broca’s Area causes a
person to struggle formulating words while still being
able to comprehend speech.
• Wernicke’s Aphasia – Damage to Wernicke’s Area
would cause a person only to be able to speak in
meaningless words.
• Example of Wernicke’s Aphasia: Asked to describe a
picture of two boys stealing cookies from behind a
woman’s back, a patient responded,
• “Mother is away her working her work to get her better,
but when she’s looking the two boys looking the other
part. She’s working another time.”
• Mnemonic to remember: You can't read Wernicke's
words and Broca's makes you babble
Language Areas of the Brain
How We Read Out Loud