Psycholinguistics

Psycholinguistics and Neurolinguistics

Psycholinguistics: study of language acquisition, storage, comprehension, and productionNeurolinguistics: study of the neural and electrochemical bases of language development and use

Brain Architecture

Right and left hemispheresHemispheres are connected by the corpus callosumBrain is covered by a membrane called the cortexBumps on the brain are called gyri, depressions are fissures

Cortex AreasAuditory cortex: receives and identifies auditory signals; Converts them into forms understandable by other areas of the brain

Visual cortex: receives and interprets visual stimuli; Storage site for pictoral images

Motor cortex: sends signals to muscles to make them move

Language Centers of the Brain

Broca’s areaLocated at the base of the motor cortex Responsible for organising articulatory patterns of languageDirects the motor cortex when talk is requiredControls use of inflectional and function morphemes

Language Centers of the Brain

Wernicke’s area:

Located near the back of the auditory cortexResponsible for the comprehension of wordsSelects words when producing language

Language Centers of the Brain

Arcuate FasciculusNerve fibers connecting Broca’s and Wernicke’s areasAllow the two areas to share informationRequired for accessing of the ‘mental lexicon’

Language Centers of the Brain

Angular GyrusLocated between Wernicke’s area and the visual cortexConverts visual stimuli into auditory stimuli and vice versaAllows matching of spoken and written forms to the objects they describeCrucial for reading and writing

Language Disorders

Aphasia:

“…An inability to perceive, process, or produce language because of physical damage to the brain,” (p.62).

Language Disorders

Broca’s aphasiaIndividuals suffer from an inability to plan the motor sequences for spoken or signed languageComprehension is not affected; This is an expressive disorderSpeech is halting, patients have a hard time forming wordsSentences may lack inflection and/or function morphemes (e.G. To, the, etc.)

Language Disorders Wernicke’s aphasia

Individuals suffer from the inability to understand the speech of othersThis is a receptive disorderPatients may produce semantically incoherent speech, e.G. Use of circumlocutionsSyntactic word order may be altered

Language Disorders

Conduction aphasiaResults from damage to the arcuate fasciculusIndividuals may sound like sufferers of Wernicke’s aphasia (fluent but meaningless speech)Sufferers will be able to understand speech, but not to repeat itResults from the inability to transmit information from Broca’s to Wernicke’s areas and vice versa

Language DisordersAlexia:

Caused by damage to the angular gyrusThe inability to read and comprehend written wordsCaused by the inability of the angular gyrus to match the visual word to the phonetic form in Wernicke’s area

Agraphia:The inability to write wordsCaused by the inability of the angular gyrus to relate the phonetic form of a word to the written form

(Not related to dyslexia, which is caused by a structural portion difference of the temporal lobe, and which may be overcome with proper training)