Language

Motor Regions

primary motor cortex: motor neurons control muscles involved in speech production
  * jaw
  * lips
  * tongue
  * vocal cords
basal ganglia: facilitates automatic sequences of behaviors needed for speech

Perception

Broca’s Area

involved in language production
location: left frontal lobe
function: language production
  * prosody: rhythmic emphatic melodic aspects oof speech
  * word choice
  * grammar
  * articulation
broca’s aphasia: difficulty producing language especially speech
neural mechanism:
* motor memories about sequences of muscular movements needed for speech
* motor neurons control motor cortex outputs to the mouth tongue etc

Wernicke’s Area

involved in meaningful language production and comprehension
location: superior left temporal gyrus near the auditory cortex
wenicke’s aphasia: difficulty comprehending or producing logical language
Neural mechanism: contains memories of sequences of sounds that constitute words
comprises the dictionary of the brain along with the posterior language area
posterior language area: regions surrounding wernickes area
* integrates the sensations and memories to form definitions or meanings of words

Lateralization

left hemisphere: dominant for speech and language production in 90% of people
* wernickes and brocas area in the left hemisphere
right hemisphere:
  * language abour spatial relationships
  * abstract language compression
  * prosody: rhythmic emphatic melodic aspects of speech
    * the man walked to the grocery store
split brain operation: surgical severing of the corpus collosum isolating the left and right hemispheres
* most abilities remain
showinf image to one visual field allows scientists to derermine the roles of the oopposite hemisphere
  * show apple to left
  * right recieves
  * cannot name but can draw stimulus w left hand

difficulty producinglanguage especially speech
* slow labored articulation the lacks prosody
3 deficits
  * agrammatism: difficulty using grammatical constructions
    * Difficulty using function words (i.e. a, the, about) →speech mainly composed of content words (i.e. nouns, verbs)
    * Grammatical markers (-ed)
    * Comprehending grammatical aspects of language produced by others
  * anomia: word finding difficulty
  * articulation difficulties: impaired pronunciation

difficulty comprehending language and producing meaningful speech
  * Little distress or awareness of own aphasia
  * Speech is meaningless & illogical
  * Few content words, and those that are used to not makes sense
  * Impaired comprehension of others’ speech
patients cannot correctly name common objects
3 major deficits
  * spoken word recognition: WA symptomology consist of some components of pure word deafness
    * pure word deafness: left damage to temporal. lobe impairs analysis of sounds of words
      * Auditory perception of timing of complex sounds to produce speech
      * Can speak but may “forget” pronunciation over time
  * language comprehension: requires linguistic information from memory
    * WA symptomology consists of some components of transcortical sensory aphasia
    * Transcortical sensory aphasia: Damage to auditory regions surrounding Wernicke’s area (posterior language area)
      * Word repetition intact, but cannot comprehend meaning of others’ or own speech
  * converting thoughts into words:
    * WA symptomology consists of some components of anomic aphasia
    * Anomic aphasia: partial amnesia for words →difficulty finding the appropriate words
    * Patients with anomic aphasia can comprehend other’s speech
      * those with WA cant \n

Arcuate Fasciculus: bundle of axons connecting Wernicke’s and Broca’s area, conveys speech sounds from auditory cortex to frontal lobe
Conduction Aphasia: damage to arcuate fasciculus
* Symptoms: fluent & meaningful speech, \n but poor repetition of non-words
Evidence for two pathways

1. Direct pathway: Arcuate fasciculus

     1. Auditory information
     2. Function: repetition
  2. Indirect pathway: Wernicke’s Area →Parietal Cortex→ Broca’s Area

     1. Information about meaning
     2. Function: comprehension