Hemispheric Specialization
Are you in your right mind?
Severing the Corpus Callosum
Corpus Callosum
• Used as a last resort
for seizure treatment.
• A form of
Psychosurgery
• Led to Sperry sharing
the Nobel Prize with
Hubel and Weisel.
Right Brain
Left Brain
Random
Logical
Intuitive
Sequential
Holistic
Rational
Synthesizes
Analyzes
Subjective
Objective
Wholes
Parts
How do you know which?
• You can look at
standard behaviors and
see which hemisphere
is dominant.
• http://www.mtsu.edu/~
devstud/advisor/hemis
pheric_dominance.htm
l
Qui ckTi me™ and a
GIF decompressor
are needed to see this pictur e.
Which side do you use.
•
You responded as a right brained person to 15 questions, and you responded as a left
brained person to 4 questions. According to the Hemispheric Dominance test, you use
your right brain the most. The summary briefly describes your dominance type.
Remember, this only represents half of the picture. After you read the description, click
on the link at the bottom of the page to find out how to use this information to improve
your study strategies. Do not forget to print your results, if your instructor has requested
you to do so.
•
•
Type of Cognitive Processing
Brief Description
•
•
Holistic
first,
Random
•
•
Concrete
Intuitive
•
•
Nonverbal
Fantasy-Oriented
Processing information from whole to part; sees the big picture
not the details.
Processing information with out priority, jumps form one task to
another.
Processes things that can be seen , or touched - real objects.
Processes information based on weather or not it feels right know
answer but not sure how it was derived.
Processes thought as illustrations.
Processes information with creativity; less focuses on rules and
regulations
Roger W. Sperry
• Roger W. Sperry (1913-)
• Neurologist who
pioneered hemispheric
specialization.
• One of his protégé’s
Ronald Myers
experimented with
severing of the corpus
collosum in cats.
• This became a method to
reduce seizures in
epileptic patients.
Wistar Rats
They referred to the
procedure as “mental
floss”
• Roger Sperry and
Joseph Bogan first
worked with rats.
• They split the corpus
callosum on the rats
using very fine wire.
Michael Gazzaniga
•
" There isn't ten cents worth of
difference between the Kalahari
bushman and the Oxford don. ”
•
Has done pioneering work in
hemispheric specialization.
He has confirmed that the right
hemisphere is dedicated to
recognition of upright faces.
•
Optic Chiasm
• The diagram to the
right is with an intact
corpus callosum.
• If the corpus callosum
is severed the
communication
between hemispheres
is interrupted.
Notice that the Optic Nerve is not
separated. Both Hemispheres get
visual signals.
Corpus Callosum fMRI view
Determining Specialization
Boy scouts are sitting there again. I’d say something really
exciting, but this isn’t too exciting. I don’t know what’s
happening. I see a guy sitting there. That’s all. And an ashtray
there. I don’t know. He shouldn’t be smoking around the boy
scouts, that’s for sure. If that’s where he is. And then there’s a
little boy sitting at the end of that bench.
Norman Rockwell
-Patient with right-hemisphere
damage
That’s probably a young boy - young man. Probably calling on
his girl’s parents. It’s a wooden bench - pine bench.
-Patient with right-hemisphere
damage
Cerebral Dominance
• Split Brain research has increased interest in
hemispheric dominance.
• You have a dominant hand
• You have a dominant foot
• …etc.
• Therefore you have a dominant hemisphere.
Left Handedness (sidedness)
• Theories include
genetic factors,
prenatal learning, or
congenital brain
damage.
• Attempts to alter
dominance can have
detrimental effects.
Reasons for Attempts at
Alteration
• Handedness is the most visible sign of dominance.
• A left handed compliment is not really a compliment
• In Latin “sinister” is the word for left-handed. Right
handedness is “dextrous”
• In French “gauche” is left and is equated with a remark
that is in bad taste.