Language

• Phoneme


  General sound that usually has no meaning on its own. Most granular unit of language
• Morpheme


  Second unit of language that refers to a combination of phonemes. Suffixes and entire words fall under this (so singing is one, but so is just "ing" because it conveys an action)
• Syntax


  Third unit of language that refers to the information got when words are combined into sentences. Grammar and the meaning it gives also falls under this
• Semantics


  4th, largest unit of language, refers to the meaning we get from words, like understanding them within context or not taking expressions literally
• Only one hemisphere has most of the control over language. in 90% of righties and 50% of lefties, it's the left hemisphere
• The right hemisphere is not completely useless for language; it still activates to understand things like irony and nonliteral language
• Wada test


  Presurgical assessment to minimize the risk of a patient losing their language skills. Anesthetizes one hemisphere using sodium amytal. Once that side has gone limp, the patient is asked to count. This is so that the doctors are sure the language is localized where it is so they dont mess with it
• Sodium amytal


  GABA receptor positive allosteric modulator that acts as an anaesthetic
• Now instead of the Wada test we just use the fMRI technology that became cheaper and more widely available throughout the 2000s to find out where language is lateralized by giving a patient language-related questions or tasks and seeing which side shows more activity
• Aphasia


  Language disorder. 180000 new cases every year in the US, often because of strokes. Can be helped with speech therapy, which shows off the brain's plasticity
• Broca's aphasia


  When a patient speaks non-fluently and only in short nouns or verbs with no tenses or conjugation. They are super frustrated because their comprehension is perfect they just cant express themselves. The same goes for writing and even ASL
• Patient Tan


  Louis Victor Lebourgne, man who could only say the word "tan" to express himself, and used it to represent every word
• Broca's area


  Part of the posterior IFG that is involved in language, was missing in patient Tan
• Inferior frontal gyrus (IFG)


  Contains Broca's area, is one of the first structures identified that had something to do with language
• Wernicke's aphasia (or receptive or fluent)


  Affects superior temporal gyrus. Patients have no issues producing sound, but have serious understanding impairments and are speaking fluently in complete gibberish. They experience paraphasia, anomia, and circumlocation
• Paraphasia


  When you create a nonword usually from mispronunciation. Happens in people with Wernicke's aphasia
• Anomia


  When you can't remember a word. In Wernicke's aphasia, they just replace it with "stuff" or "things" in the middle of a sentence
• Circumlocation


  When you forget the name of a thing so you try to use a roundabout way of getting to what you want to say
• Superior temporal gyrus (Wernicke's area)


  Brain structure linked to language comprehension
• Arcuate fasciculus


  Band of white matter spanning the IFG and STG so they can have a healthy communication
• Conduction aphasia


  When the arcuate fasciculus is damaged and people have issues repeating language they hear, but no other major deficits
• Global aphasia


  When you can't speak at all because there is damage to IFG STG and arcuate fasciculus and have issues repeating words spoken to them. If it was because of a stroke they might be able to learn how to communicate using pantomime or facial expressions, but mostly its over for bro
• Wernicke - Geschwind model


  Suggests that language is passed linearly though a bunch of different brain structures, and each one is responsible for decoding a specific part.
• Wernicke - Geschwind model:

  A1 --> STG (wernicke's area) where it gets meaning of the sounds --> across arcuate fasciculus --> IFG (Broca's area) where it plans out what you say and the motions necessary --> motor cortes which sneds signals to the speech muscles
• Developmental dyslexia


  Difficulty understanding the phenomes of words in writing and making sense of them. Might have something to do with wonky V1 communications to the language systems. No issues with oral comprehension, just problems reading