Hemispheric Specialization

1. Hemispheric Specialization Are you in your right mind?

2. 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.

3. Right Brain Random Intuitive Holistic Synthesizes Subjective Wholes Left Brain Logical Sequential Rational Analyzes Objective Parts

4. How do you know which? • You can look at standard behaviors and see which hemisphere is dominant. • http://www.mtsu.edu/~devstud/advisor/hemispheric_dominance.html

6. 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   Processing information from whole to part; sees the big picture first, not the details. • Random   Processing information with out priority, jumps form one task to another. • Concrete   Processes things that can be seen , or touched - real objects. • Intuitive   Processes information based on weather or not it feels right know answer but not sure how it was derived. • Nonverbal   Processes thought as illustrations. • Fantasy-Oriented   Processes information with creativity; less focuses on rules and regulations 

7. 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.

8. 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.

9. Michael Gazzaniga Making reference to the right hemisphere! • " 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.

10. 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.

11. Corpus Callosum fMRI view

12. Determining Specialization

13. Norman Rockwell 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’tbe 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. -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

14. 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.

15. Left Handedness (sidedness) • Theories include genetic factors, prenatal learning, or congenital brain damage. • Attempts to alter dominance can have detrimental effects.

16. 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.