Introduction to Neurolinguistics

• Study notes on neurolinguistics are presented

Introduction / Definition

• Neurolinguistics is an interdisciplinary science examining the relationship between language and the brain
• Neurolinguists explore how the brain produces, understands, and manages language by combining neurology, linguistics, and psychology
• The core objective in neurolinguistics is understanding the fundamental components of the linguistic process (cerebral localization and function, cognitive interaction of mechanisms, grammatical linguistic organization), which facilitates the observation of language dysfunction
• It helps comprehension of language breakdowns resulting from genetic, developmental, or environmental injuries to the brain

Historical Context

• Phrenology became popular in the 19th and 20th centuries
• It took a localist approach
• FJ Gall developed the basis of neuropsychology and proposed two central ideas:
  • Mental functions are fractionated and autonomous
  • These functions are localized in the brain
• This concept suggests that the brain consists of potentially localizable areas
• Observations of bumps on the skull where they reflect a person's character was an initial method
• The hypotheses couldn't be validated, for example, connecting large eyes to better speaking ability

Linguistic Modeling Overview

• It succeeded phrenology as a field
• Jacques Lordat was the pioneer of cognitive neuropsychology, He proposed a working model of language within the brain
• Verbal production consists of five stages
  • Framing the thought
  • Structuring into propositions
  • Transforming into sounds
  • Creating syntactic structures
  • Executing the sounds
• Control occurs over another set of five stages
  • Managing prosody and rhythm
  • Ensuring muscle stability
  • Studying speech organs
  • Compensating function
  • Monitoring speech

Perspectives on Neurolinguistic Study

• A medical and neuroscientific perspective focuses on disorders such as Dysarthria: Difficulty in articulating sounds, Palatine cleft: Malformation of oral structures and Auditory deficiencies that affects language reception and production.
• Linguistic domains of study include: phonetics (problems articulating sounds); phonology (incorrect use of sounds); prosody (intonation and rhythm alterations); grammar (problems with sentence structure); semantics (comprehension deficits), and pragmatics (interaction issues)
• A neuropsychological perspective tests information processing models using behavioral and neurophysiological tasks
• It examines how these models illustrate individual disorders and capabilities, further involving the analysis of deficiencies in perception, stored knowledge (lexical semantics/memory), and verbal output

Utility of Medical Descriptions

• Descriptions identify progressive neurological deficits
• Interventions such as surgery can be planned around descriptions
• Accurately diagnosing medical ailments can be difficult
• Predicting language development evolution can be difficult from only a diagnosis

Difficulties of medical descriptions

• The approach is multidimensional
• It emphasizes describing a disorder rather than explaining it
• Establishing a relationship between a disorder, cognitive processes, and its treatments can also be challenging

Decoding Cognitive Disorders

• Cognitive and neurophysiological bases of linguistic disorders need to be found
• Models should give insight to key treatment steps
• Analysis is performed at various levels
  • Behavioral (examines verbal/non-verbal acts)
  • Cognitive/algorithmic (mental processes to resolve the problem)
  • Neurophysiological (localizes active brain regions)

Hypotheses and Considerations

• General disorganization in speech (gnosis relating meaning of objects and praxies relating movement) occurs both within and beyond language systems
• The behavior is related to activating certain zones

Introduction and Methodological Diversity

• Offline measurements regard behavioral response to thoughts where error production, pauses, corrections, and memory are observed
• Online measures regard cognitive and neurophysiological effects, with reaction time as the temporal duration of thought when exposed to electrophysiological measures, gestures, and speech rate
• Populations of monolinguals/bilinguals, children, and those with disorders are looked at

Categories for Disorders

• Disorders are classified into specific language disorders, such as dyslexia and dysgraphia
• Pragmatics, discourse, syntax, morphology, semantics, memory/lexicon, and orthography are affected by learning disorders
• Speech disorders include speech/language delays, articulation problems, verbal dyspraxia, and dysarthria
• Conditions include voice and verbal fluency disorders, as well as stuttering
• Language disorders can result from accidents, aphasia, or verbal amnesia

Language Disorders

• Language disorders are either acquired (loss of a function) or developmental (anomalous in development, durable, and developing)
• Both are identifiable via qualitative/quantitative tests showing a difference by at least two standard deviations from the norm
• Poetic approaches lack rules or exceptions

Types of Language Disorders

• Developmental disorders have abnormal language development
• Acquired disorders appear after normal development, like aphasia following a stroke
• Problems can be isolated, where
  • Functionality are transient in nature
  • Structural is when, for example, spoken-language dysphasia or written-language dyslexia occurs
• Secondary problems are linked to other pathologies: mental retardation.

Severity of Language Disorders

• Severe disorders exert influence and impact on various levels
• Light disorders can be brief

Existence of language Disorders

• Major cognitive impairment with focal brain injury that spares long term memory or mathematical capabilities
• Absence of a language impairment like in Williams and Down syndrome affects the comprehension and production of language and also reading/writing
• Aphasia is language disturbance impacting both language comprehension and capabilities to read/write due to the brain damaged through accident, neurodegenerative ailment, or trauma
• These can lead to patients struggling to assemble the words when reading or assemble names of objects
• Classified as acquired, isolated, specific, linked to cerebral injury and is severe

Interface Between Language, Cognition and the Brain

• Autonomy suggests that language and cognition work independently because they're intrinsic and modularized
• Cognitive determinism indicates cognition has an impact on language: its richness influences language
• Linguistic determinism assumes influence upon cognition: input will inflect the cognitive system
• The position of the interaction is variable under different tasks and hence a moderated stance of determinism

Brain and Language Localization

• Localism links each language function to certain area
• Associationism dictates interaction amongst brain regions
• Holism believes in global co-operation of areas on generating language
• Dissociation allows deduction via separating mental processes

Forms of Dissociation

• Simple dissociation affects one function while leaving others unharmed
• Double dissociation affects two functions in distinct manners and hence their independence

Theoretical Models

• Shannon's Model proposes that a source produces, encodes, and transmits a message through a noisy channel to a receiver
• Osgood's Model approaches interaction wherein the input stimulus leads to central processing being influenced by previous knowledge, and results in an output
• Nespoulous suggested a model dividing in two areas
  • Encoding
  • Decoding
• Nespoulous criticized the existing modular approach, advocating for a contextual one

Critiques of Other Models

• Excessive interactions exist between cognition and language
• Contexts get unheeded without observing verbals and their interactions
• Definitions lack elucidation
• Integrative studies need approaches

Dell and Levelt Model

• Levelt suggests a person has multiple senses alongside thrematic abilities for performing an emotion
• Levelt's Model of lexical entries have: lemma (meaning) and form (lexeme)
• Bock's Model suggests information moves bidirectionally
• Dell's Model has three tiers of connection: semantic, lexical, phonological

Cognitive Models

• Strackhouse & Wells model sensoriel, catégorisation phonémique, représentation phonémique, représentation sémantique, programmes moteurs and production orale
• Hagoot model is Memory, lexique mentale and la mémoire that résulte l'encodage and the stockage
• All show importance of modularity in the brain

Neuroanatomical Foundations

• J. Lordat recognized that the hearing process needs to be intact during paralysis
• Localization is located in the top third posterior of the left frontal gyrus

Areas in the Brain

• Broca's Area exists in the left inferior frontal lobe that creates syntax
• Wernicke's Area happens in the left lobe and it is responsible for sound comprehension
• The Arcuate Fasciculus: communication in a bundle

Module

• The Brain is a functional set of rules interlinked
• Damage can cause issue to coordination and structure

Criticism

• Passage requires a location to involve a network
• Module de Wernicka divides functions without account

Loop

• Geschwind-Wernicke: a language loop in the brain with verbal messages
• Kemmerer and Wolff found meaning to impact the brain: Temporal impacts faces and occipital relates to nature
• In Mesulam an inter-connection occurs between zones

Parts of Brain

• The inferior parietal lobe links Wernicke and Broca (angular and supramarginal gyrus)
• Electrodes in EEG track the neurons through frequency
• Unicell recordings record neuron insertion
• MRI studies the structures of the brain
• Foncionelles in brain activity variation
• TEP test traces radioactive activity
• MEG scans fields and temporals

Right Hemiperies

• The non-verbal posture is in language
• Language is managed by the left cerebral, with the right in emotion

Information from the Right Hemisphere

• Information can be perceived from the speaker when the left side can’t grasp the context.
• Anatomical models propose two routes
  • the articulatory of the sensory motor
  • combinatorial from the lexical
• Sensory models require feedback during production of how the brain and perception interact
• Conceptual systems must be cognitive and have world knowledge

Models of Language

• There’s areas to diverge and merge between specificities
• Production varies across both structures
• Conduction causes lobe transmission issues
• Corex causes problems systematically

Aphasia's Types

• Wernicke includes grammatical correctness or not
• Conduction is correct
• There is touch is sensory of correct ability for hemianopsia

Aphasia's Results

• Anomic and Amnestic is the concepts
• Broca doesn’t have flow and limited
• Trans cortical lacks structure
• Global destroys understanding

Alxie's Results

• Paraphrases happen in words
• Hemiplegia happens on opposite sides = Agrammatisme is effected during a sentence from time and grammar

Language Development and Troubles

• Language develops through neural capacity
• Activity depends on the function
• There can be speech and language delays
• Dyslexia occurs
• There can be delays from the oral
• There can be steps to log to the alphabetic and graphs

Stages of Reading (Frith)

• Logographic (shape-orientation)
• Alphabetic (conversions/correspondences)
• Orthographic (the motor portion)

Disorders

• Disorders can be the phonological representation
• Deficit and linguistic skills
• Dysphasia and impairments
• Linguistic awareness happens through hearing
• Cognitive skills impact the brain
• Seymour’s model includes alphabet

Basis

• The anatomy is normal

Linguistics

• DeFries accounts for family
• Occurs in waves

Aphasia's Stages and Outcomes

• Impairments of articulation cause uncorrect phonetics during expression
• Retards in syntax/lexicon cause impairments
• Stuttering is also related to breathing
• Tonics or phonics occur also impacts the use

Types of Dysphasie

• During articulation a variety the function from the linguistic.
• Intellect and sensory
• Encording and intellegence
• The receptive has comprehension

Dysphasie Details

• Hard understanding
• Troubles of concepts
• Not fluent and needs gesture communication