lateralization of function

• function or behavior found in only one cerebral hemisphere

• why might there be lateralization?

• what are its advantages and disadvantages?

lateralized behaviors

• left hemisphere– analytical abilities– quantitative skills– language

• right hemisphere– music– spatial abilities– artistic abilities– emotions– facial recognition

Language

• most well studied lateralized behavior– 95% of right handed

have speech on left– 70% of left handed

have speech on left

aphasia – language deficit that cannot beattributed to motor, motivational, sensory or other explanations

Broca’s Aphasia

• characterized by broken halted speech,

absence of prosody

• comprehension – fairly good; ability to read – fairly good

Wernicke’s aphasia

• fluid aphasia, deficits appear to be in comprehension; words are nonsensical

• comprehension – poor

• reading ability - poor

Wada test

• injection of sodium amytal or sodium amobarbital – anesthetic

• used to determine hemisphere important for speech

Another way to study lateralized behaviors is via “split brain” patients

• split brain surgery

consequences of “split brain”

• initially – – “Breakdown of the Bicameral Mind”

• Julian Jaynes

– subsequently – only can really tell by experimental manipulations in the lab

Emotions

• emotional facial expressions– evolutionary explanation

Emotions

• emotional facial expressions– evolutionary explanation

• role of right hemisphere– recognition of emotion – display of emotions– chimera

• brain damaged humans

brain regions involved in emotion

• limbic system- – components of limbic system- includes

hypothalamus, hippocampus, amygdala, olfactory bulbs, septum

• sits within the temporal lobe– temporal lobe epilepsy

Kluver Bucy Syndrome

• Kluver Bucy syndrome– associated with temporal lobe damage

characteristics:

Kluver Bucy Syndrome

• Kluver Bucy syndrome– associated with temporal lobe damage

characteristics:

1. extraordinary tameness

Kluver Bucy Syndrome

• Kluver Bucy syndrome– associated with temporal lobe damage

characteristics:

1. extraordinary tameness

2. lack of fear

Kluver Bucy Syndrome

• Kluver Bucy syndrome– associated with temporal lobe damage

characteristics:

1. extraordinary tameness

2. lack of fear

3. put anything in the mouth

Kluver Bucy Syndrome

• Kluver Bucy syndrome– associated with temporal lobe damage

characteristics:

1. extraordinary tameness

2. lack of fear

3. put anything in the mouth

4. mount anything