1. Mind, Brain & Behavior Wednesday March 12, 2003

2. Eating Disorders  Anorexia Nervosa – deliberate starvation due to psychological factors. Insufficient body weight Distorted body image, food obsession Anorexics have normal appetite  Bulimia Nervosa – food binging followed by purging with laxatives or vomiting. Normal body weight

3. Obesity  Based on height and weight, a body mass index above 30 (above 25 is overweight). http://www.caloriecontrol.org/bmi.html  Causes: Different metabolic rate Larger adipocytes More vulnerable to food cues, finicky  Recidivism after dieting = 90+% in all forms of treatment.

4. Language Chapter 34

5. Features of Language  Creativity – we create meaning by using grammatical rules to generate new sentences.  Form – language is made up of smaller units (phonemes, morphemes, words, sentences) combined using rules.  Content – meaning can be abstract, context independent, emotional.  Use – language has social purpose.

6. Animal Models of Language  Chimpanzees cannot produce speech sounds because they lack the vocal apparatus.  Chimpanzees (Washoe, Kanzi) and other apes can manipulate symbols. Language development goes to a certain point then stops – not fluent and creative like humans. No evidence that animals form abstract mental representations of meaning and think using symbols.

7. Innateness of Language  Language and sign language are both lateralized to left hemisphere.  The planum temporale is larger in the left hemisphere in most (67%) right-handers.  This asymmetry is present before birth.  Infants can differentiate speech sounds at birth – critical period for recognizing phonemes for a particular language.  Universal regularities in language acquisition.

8. Aphasias  Aphasia – a disorder of language.  Wernicke’s aphasia – difficulty understanding written or spoken language. Empty speech. Logorrhea (too much speech).  Broca’s aphasia – difficulty generating fluent, grammatical speech (omit articles, adjectives).  Conduction aphasia – disconnection between Broca’s & Wernicke’s area – cannot repeat.

9. Aprosodia  Prosody – musical elements of speech, including stress, pitch, rhythm.  Affective components of language – convey attitude, value, emotion.  Lateralized to right hemisphere. Damage to frontal cortex results in flat tone of voice regardless of emotional state. Damage to posterior areas of brain result in inability to comprehend other people’s prosody.

10. Reading and Writing Disorders  Alexia and dyslexia – inability or difficulty reading. Dyslexia is congenital, alexia is acquired.  Agraphia – inability to write.  Word blindness – inability to comprehend words. Pure – alexia without agraphia.

11. Dyslexia  May be congenital or acquired through brain injury. Inability to read despite normal IQ & cognition.  Causes: Deficient phonemic processing (speech sounds). Visual processing defects due to abnormalities in connections between visual and language areas. Deficit in development of hemispheric dominance – occurs in left-handers, letter reversals.

12. Dyslexia (Cont.)  More causes: Cytoarchitectonic abnormalities, such as incomplete segregation of layers in planum temporale, clusters of misplaced neurons. Inability to process sensory input with adequate speed – magnocellular conduction too slow.

13. Ideographs  Ideographs – characters that stand for an entire concept, representing a root word.  Some writing systems have two ways of expressing language: Katakana (phonetic) vs kanji (ideographic).  Processing of kanji occurs in a different region than processing of katakana, though both are localized to left hemisphere.