1. Explain One Study Related to Localization of Function in the Brain
Explain – Give a detailed account including reasons or causes

2. Localization
The first principle of biological approach to behavior implies that behavior may be the product of brain structure - but what exactly is the connection between parts of the brain and patterns of behavior?
It is very tempting to imply that every behavior has its specific place in the brain (this idea is known as localization of function)

3. Brain Structure The nervous system is a system of neurons
Central nervous system = brain + spinal cord
Major parts of the brain:
Cortex
Outside of the brain. (chewed up gum)
Associated with higher-order functions like intellectual thought or voluntary action
Divided into four parts, or lobes:
Frontal lobe: reasoning, planning, thinking, voluntary action
Parietal lobe: movement, orientation, perception, recognition
Occipital lobe: visual processing
Temporal lobe: processing auditory info, memory and speech

4. The Four Lobes

5. Brain Structure
There is a deep crease in the cortex that divides it into the left and right hemispheres. (connected by a structure of neurons known as the corpus callosum)
Cerebellum: “little brain”. Associated with coordination of movement and balance

6. Brain Structure Limbic System: “the emotional brain”
Thalamus: almost all sensory organs reach this “hub” before they are connected to the cortex
Hypothalamus: emotion, thirst, hunger
Amygdala: memory, emotion, fear
Hippocampus: learning, memory (transferring from short-term to long-term memory)

7. Limbic System

8. Brain Structure Brain stem: underneath the limbic system
Regulates the basic vital processes such as breathing or heartbeat.
Connects the brain to the spinal cord
This part of the brain is very much like the entire brain found in lower animals such as reptiles

9. Explain One Study Related to Localization of Function in the Brain
Broca’s Area ?
Wernicke’s Area?
What do these areas do and where are they located?

10. Broca’s area Left frontal lobe
Ability to understand and make grammatically complex sentences
Broca’s aphasia – Problem producing speech but able to understand it
Paul Broca (1861) Case Study – Tan

11. Case Study: Tan
Louis Leborgne, now better known as ‘‘Tan’’, lost the ability to speak when he was 30.
Tan developed gangrene and was admitted for surgery…to be performed by French physician Paul Broca who also specialized in language
By that time “tan” was the only syllable that Leborgne could pronounce.
His intelligence was intact, as he understood everything he was asked and tried to communicate back…he just couldn’t say anything other than “tan”
When Tan died at the age of 51, an autopsy of his brain was carried out and it revealed a lesion in the frontal area of the left hemisphere

12. Broca’s Area

13. Wernicke’s Area Carl Wernicke (1874) Left posterior temporal
Responsible for the comprehension of written and spoken language
Wernicke’s aphasia – patients could produce speech but couldn’t understand it

14. Wernicke’s Area

15. Research Opposing Strict Localization
Karl Lashley ( ) used the technique of measuring behavior before and after a specific carefully controlled induced brain damage in the cortex of rats.
He would train a rat to run through a maze without errors in search of food
After learning occurred, he would remove an area from the cortex and then place the rat back at the start of the maze and register the change in behavior
He removed varying portions of the cortex, ranging from 10% to 50% in some rats
The idea was that if memory of the maze is localized somewhere, then by removing area after area you will finally find the specific region in the cortex responsible for it
The research turned out to be a failure so Lashley concluded that memory was distributed rather than localized

16. Explain One Study Related to Localization of Function in the Brain
Recent research shows that the right brain plays more of a supportive role in language than originally thought

17. Explain One Study Related to Localization of Function in the Brain
Split-brain cases
Split-brain studies represent research into lateralization – the division of function between the two hemispheres.
Lateralization is a special case of localization
Split brain patients had abnormal brains even before their operations
These cases suffer from population validity problems, meaning that the results do not generalize well to persons with normal brains

18. Split-Brain Studies Roger Sperry & Michael Gazzaniga (1967)
Aim: to test the theory of lateralization & to see if the two hemispheres have uniquely different functions
Methods: Four participants sat in front of a screen and looked at a dot in the middle of it while visual stimuli would be presented for one tenth of a second either to the left or right side of the screen. Also, a variety of objects were placed behind the screen so that participants could feel them with their hands.

19. Split-Brain Studies Results:
when shown a picture of a spoon to the left visual field (processed by the right brain) and asked to name what they saw, the patients said nothing. However, when asked to pick a corresponding object from a group of objects behind the screen, they felt around and picked the spoon. The right hemisphere saw the spoon and picked it from behind the screen using the left hand, but the center of speech is in the left hemisphere so the patients were unable to explain what they saw and what they did
However, when a simple word like “pencil” was flashed to the right hemisphere, the patients were able to pick a pencil with their left hand. This shows that the right hemisphere does have some amount of language comprehension and that language is not exclusive to the left hemisphere

20. Split-Brain Studies Results:
when the word “heart” was flashed on the screen so that “he” was shown in the left visual field and “art” in the right visual field, the patients said they saw “art” but pointed (with left hand) to the card with the word “he” on it. This corroborates the previous findings, but also shows that the two hemispheres process stimuli independently.
Some patients were able to spell simple words with their left hand. For example, when researchers placed four plastic letters in a pile behind the screen, one patient was able to spell “love” with his left hand (the instruction was simply to spell a word). After completing the task, the subject was not able to say what word he had just spelled. This shows that the right hemisphere is even capable of language production, but only in the simplest form and only in some patients.

21. Explain One Study Related to Localization of Function in the Brain
Reductionist view of localization?
Popular culture has contributed to the common reductionist view of localization
The modern research on localization does not support a strict division

22. Explain One Study Related to Localization of Function in the Brain
Carreiras and colleagues (2005); The whistling language;
How are the brain changes in Silbo users explained?
Silbo uses pitch and melody that are distinct from spoken language.
But at the same time, the sounds are a way to communicate.
Even if the whistled sounds are unusual, the left hemisphere responds to them because they are used as language
Right hemisphere is also activated – which is evident in bilinguals

23. Explain One Study Related to Localization of Function in the Brain
Meta-analysis?

24. Explain One Study Related to Localization of Function in the Brain
Meta-analysis – looks for themes in a large body of studies on the same topic that use different designs
Makes sense of a wide range of studies on a topic
It organizes hundreds of studies in such a way to make them comparable
Researchers conducting meta-analysis create new data by sorting studies into categories
Compare the effect size across a wide range of studies to create the best generalizations

25. Explain One Study Related to Localization of Function in the Brain
Hull & Vaid (2006)
Examined 23 studies on a total of 1234 normal monolingual and bilingual participants
All studies tested monolinguals and bilinguals speaking the same languages
Aim – to see if and under what conditions second language experience affected brain development

26. Explain One Study Related to Localization of Function in the Brain
Previous studies showed that the right hemisphere was not important in language processing
Hull and Vaid believed the right brain is important
Studies suggested that while the left hemisphere was dominant for language processing, the right hemisphere supported the process more than was typically believed

27. Explain One Study Related to Localization of Function in the Brain
Secondly, case studies on language loss and recovery in bilingual aphasics led researchers to believe that multiple languages might be localized in different areas of the brain
Third, the age that someone acquires a second language and their level of proficiency might affect the pattern of left hemisphere dominance

28. Explain One Study Related to Localization of Function in the Brain
Important findings of the meta-analysis
Early experience appears the key variable
Monolinguals and bilinguals who acquired their second language after age 6 showed the most left hemisphere dominance
Early bilinguals were bilateral – the closer in time two languages are acquired, the more similar the brain localization
There were no significant hemispheric localization differences between the proficient and non-proficient bilinguals