Outline Lateralization of Function Language Communication Disorders What is a language System of rule based communication that combines symbols sounds and gestures in order to express a meaning idea or thought Transmit info Express thoughts and emotions Automatic complex and coordinated What is a language System of rule based communication that combines symbols sounds and gestures in order to express a meaning idea or thought Use of vocalization to communicate No connection between symbol and what it signifies Passed from generation to generation Communication follows social rules Can communicate about objects and events that are distant in time and place Origin of Language Chomsky and Pinker argue for innate ability to learn language No specific instruction needed to learn language suggestive of language module Williams syndrome Origin of Language FOXP2 genes located on chromosome 7 Modern language acquired 100 400 000 ya due to specific mutation Origin of Language FOXP2 genes located on chromosome 7 KE family FOXP2 mutation associated with disrupted speech production and comprehension Gene codes transcription factor which regulates expression of large number of genes Areas in blue functionally or structurally abnormal in KE family Schizophrenia Many symptoms associated with interpretation and organization of language Generally show no hemispheric asymmetry for language or instead mirror asymmetry with language lateralized to right hemisphere Mixed or ambiguous handedness 1 of population throughout world yet patients have low reproduction rate must be linked to some positive attribute Does Language Exist in Non Humans Language Are Nonhumans Animals Capable of Language Communication not the same as language Research with great apes Language Are Nonhumans Animals Capable of Language Communication not the same as language Research with great apes Mirror neurons Broca s area Bilingualism Distinguishing speech sounds most languages contain 25 40 speech sounds Infants younger than 8 months can distinguish all speech sounds even those not heard in native language l and r differentiated in English but not Japanese By 11 months infants can discriminate speech sounds from own language only supporting idea of critical periods Bilingualism Bilingualism MRI second language learning increases grey matter density in certain cortical regions Density increases correlate with language proficiency Bilingualism MRI second language learning increases grey matter density in certain cortical regions Bilingualism MRI second language learning increases grey matter density in certain cortical regions Language American Sign Language Similar language sites activated for spoken written English as ASL spoken word activation more lateralized Mechanisms of Language Contemporary Language Model word memories speech sounds generate speech associated words Wernicke Geschwind model of language Word comprehension occurs in Wernicke s area Speech response generated in Broca s area Speech production controlled via motor cortex and BG activation Contemporary Language Model Three interacting language components Language implementation system decodes incoming verbal info and produces appropriate verbal responses depends on Broca s area Wernicke s area insular cortex and basal ganglia Mediational system manages communication between implementation and conceptual systems depends on the temporal parietal and frontal lobes Conceptual system manages semantic knowledge depends on high level cortical association areas Contemporary Language Model Implementation system shades of orange Mediational system shades of blue Outline Lateralization of Function Language Communication Disorders Aphasias Brain damage that results in total or partial loss of ability to either produce or comprehend spoken language Brain of Dr Broca s patient Damage to left inferior frontal region While alive patient could say only tan when questioned Broca s Aphasia Broca s area located along inferior frontal gyrus Speech production and writing deficits Speech is slow and effortful Anomia difficulty retrieving correct words for ideas they wish to express Comprehension intact Singing still intact Wernicke s Aphasia Wernicke s Area located just below superior temporal gyrus Comprehension for both spoken and written word impaired Speech is rapid and fluent but virtually meaningless Seem unaware they make no sense Neologisms common Conduction Aphasia Transcortical Aphasias TC motor aphasia Dorsolateral PFC damage Affects higher cognitive and attentional functions related to language production Initiation of speech disrupted Unable to produce verbs related to particular nouns Transcortical Aphasias TC sensory aphasia Supplementary motor cortex damage Affects ability to understand meaning of words Speech is grammatical and fluent Reading and Writing Alexia Reading Word blindness Can recognize spoken words Left occipital cortex damage affects ability to perceive words and word like shapes Corpus callosum damage prevents transfer of info from right visual cortex to left language areas Appeared 5 6000 ya Usually localized to same hemisphere as speech Reading and Writing Agraphia Writing Inability to write Damage to motor control areas Phonological agraphia unable to sound out new or difficult words Orthographic agraphia can spell only phonetically Appeared 5 6000 ya Usually localized to same hemisphere as speech Dyslexia Dyslexia Impairment in reading despite normal intelligence and exposure 10 30 of population High heritability 40 chance sibling is also dyslexic Impaired phonological awareness ability to discriminate verbal information at level of speech sounds Difficulty discriminating rapidly presented stimuli Dyslexia Visual Perceptual difficulties Reading a word backwards net becomes ten Confusing mirror image letters b becomes d Trouble fixating on printed words Words appear to move around page Dyslexia Brain Activation and Reading Stuttering Producing repetitions or prolonging of sounds Primarily genetic in origin Both hemispheres vie to control speech production Treatments Reducing rates at which speech is produced and stress associated with the disorder Learning special breathing techniques soft voice onsets and prolongation of syllables Dopamine antagonists