Anaphoric dependencies: A window into the architecture of the language system

1
Anaphoric dependencies A window into the
architecture of the language system

• Sergey Avrutin
• Eric Reuland
• Frank Wijnen
• Olga Khomitsevitch
• Arnout Koornneef
• Natalia Slioussar
• Nada Vasic

2
Goals of the course

• Explain how language structure and neurocognitive
  organization can meet
• Provide some background on current approaches
• Present a number of issues on which current
  discussions focus

3
Overview

• Fundamentals of Linguistics against a
  neurocognitive background
• The grammatical encoding of anaphoric
  dependencies
• Linguistic architecture and cognitive
  architecture
• Language processing
• Language impairment
• Acquired
• Congenital

4
What is Language?

• Language Systematic relation between
• Forms events in an (external) medium (sound,
  gesture, ink on paper)
• Interpretations change in information state of
  the mind

5
Fundamental issues

• How did language evolve?
• What is the structure of language?
• How is language represented in the brain?
• How is language acquired?
• Focus on the relation between 2 and 3

6
How is language represented in the brain?

• Reflects general issue of the division of labour
  between brain areas
• Modularity
• Functionality
• Plasticity

7
Theoretical approach Minimalist Program The
(minimal) language system Sensori-motor
system PF-interface Computational system of
Human Language (CHL) (Lexicon) Conceptual-Inten
tional Interface (C-I interface) System of
thought
8
Theoretical approach Minimalist ProgramThe
minimal language system

• PF interface C-I interface
• Sensori- ? CHL? Interpretation
• Motor system system (system of thought)
• Lexicon
• - dedicated dedicated(?) -dedicated

9
Levelt Speaking (1989)
10
Task find map between linguistic operations and
neurocognitive processes

• PF-interface
• Computational system of Human Language (CHL)
  (Lexicon)
• Conceptual-Intentional Interface (C-I interface)

?
11
The triangle of cognitive neuroscience (Hagoort
2003)
Computational model
Neuro- physiology
Cognitive Archtecture
Neural Architecture
Neuro anatomy
Behaviour
12
A note on method

• The brain is doing a lot at the same time ?
• In whatever you try to measure, you will find a
  lot of noise
• ? no escape from forming precise (and
  falsifiable) hypotheses a theory is your eyes -
  without it you are blind

13
On the relation between linguistics and
psycholinguistics

• "The split between linguistics and
  psycholinguistics in the 1970s has been
  interpreted as being a retreat by linguists from
  the notion that every operation of the grammar is
  a mental operation that a speaker must perform in
  speaking and understanding language. 
• But, putting history aside for the moment, we as
  linguists cannot take the position that there is
  another way to construct mental representations
  of sentences other than the machinery of grammar.
•  ....There is no retreat from the strictest
  possible interpretation of grammatical
  operations as the only way to construct
  linguistic representations" (Alec Marantz,
  lecture notes 2000)

14
Correspondence Thesis

• Differences between operations within (major)
  modules of the grammatical system correspond with
  differences in processes at the neural level and
  vice versa. (Reuland 2003)

15
In plain language

• We have to figure out what the brain does in
  order to be able to figure out how the brain does
  it
• We have to figure out how the brain does things
  in order to figure out how it can do what it does
• ? the main danger is not being precise enough on
  either side

16
Tensions between requirements on Linguistic
descriptions

• What do we need for easy description?
• What do we need for explanation?
• Compare
• - Quantum physics
• - Newtonian mechanics
• For understanding planetary motion
• For understanding why there are no white holes

17
An example how local are the dependencies we
(can) compute?

• What did John see?
• What did John see
• What did John see -
• Issues of this type may occasionally seem
  abstract but are crucial for our understanding

18
The level of correpondence
19
Current views on modularity

• Is there a division of labour between brain
  areas?
• Answer There is specialisation
• Lateralisation left-right asymmetry
• Specialized areas of the cortex
• - Motor-cortex
• - Visual cortex
• - Auditory cortex
• Etc.

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Specialisation within areas

• Example (Kandel et al. 2000, Principles of
  Neural Science Ch 28)
• Visual system specific neurons for
• Black/white detection
• Colour detection
• Form detection
• Depth detection
• Movement detection
• Facial recognition

21
FUNCTIONS functions

• Kosslyn König (1995) The Wet Mind
• FUNCTIONS (Vision, Hearing, etc. ) v.s.
  functions (movement detection, depth detection,
  etc.)
•  
• Binding problem How do the different functions
  lead to one unified perception?

22
Language FUNCTION vs functions

• Is there one language system? Or
• Are there different subsystems that contribute to
  the FUNCTION Language?
• If so, what are the functions subserving
  language?
• How elementary are these functions? 
• Are there any functions dedicated to language?
•  

23
Summary of the task

• Precise analysis of the operations needed to
  capture the structure of language
• Match these operations with real time processes
  in the brain
• Identify brain areas involved in these processes

24
Methods

• Grammar Precise modeling of structure and
  interpretation
• Studying Experiments of nature language
  impairment (genetic, acquired)
• 3. Behavioral studies complexity, processing
  resources
• 4. Eye-tracking
• 5. ERP
• 6. fMRI
• 7. PET

25
Language basic structure

• Components
• Phonology
• Syntax Lexicon
• Semantics
• Discourse

26
Required for explanation

• What do we minimally need to account for language
  structure?
• What do we minimally need to assume is dedicated
  to language?
• Behind these questions
• What kind of elements and what type of properties
  can be plausibly represented in the brain?

27
Time to step back and think

• How can linguistic knowledge be mentally
  represented?
• Lexical items
• Instructions for procedures
• Ullman (2001/2004)
• Contributions of Brain Memory Circuits to
  Language The procedural/declarative model

28
The minimalist program

• Start out assuming
• What has to be the case by conceptual necessity
  (and no more)
• Add no enrichment to the system unless
  empirically unavoidable
• But be as precise as possible

29
Consequences

• Treat with suspicion
• Categories
• Labels
• Indices
• Traces

30
Lexicon

• Lexicon Atomic form-meaning combinations
  (morphemes)
• Each morpheme contains
• phonological information ? how to pronounce
• (phonology Sound system will not be discussed
  here)
• - grammatical information ? category (Noun, Verb,
  Adj., Preposition, etc.), features (person,
  gender, number, Case, etc.)
• semantic information ? concept, instructions for
  computation (quantifiers every, a, some, etc.)

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The basic combinatory process

• BINARY OPERATION Merge a , b ? a b
• But
• Not all combinations of morphemes are possible
  words
• real, real-hood, real-able, real-ish, ...
• work, work-ish, work-hood,...
• hold, holded, up-holded hold, held, up-held
• boy, boy-en boy, boys
• Morphemes select what they combine with

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Aside

• Fundamental question
• How are word classes represented in the mental
  lexicon? Or
• How are the zillions of Nouns all characterized
  as Nouns, Verbs as Verbs, etc.?
• Options
• - categorial network
• - computationally N n, ltconceptgt
• (functional n-head, v-head, etc.)
• - intrinsically inspect the concept (Vinokurova
  2005)

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Merge

• Binary merge ? asymmetry
• The effect of this asymmetry is pervasive in the
  computation of dependencies

34
Hierarchical relations Tree structures

• A
• N A
• boy -ish
• N
• A
• A A N
• un- happy ness
• N A unA- A happy nessN

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Hierarchy and Asymmetry

• Asymmetries determine interpretation
• a b c a b c
• top squadron commander
• top squadron commander
• California history teacher
• California history teacher

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Syntax the computational system

• Basic operation Merge a,b ( combine a,b)
• Each combination has a head ? represented in
  structure
• A grey N mice ?NP A grey N mice
• the N mice is the head of the Noun Phrase
• grey mice
• V feed NP A grey N mice ?
• VP V feed NP A grey N mice
• the V feed is the head of the Verb Phrase

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An elementary Tree structure

• V(P)
• N(P)
• V A N
• feed grey mice

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Basic clause structure 1

• Three types of information
• What happened to whom? Core Predicate
• (I saw) Mary feed the cat
• When did it happen? Tense/Mood
• Mary will feed the cat
• Force Assertion, Question, Command
• (I saw) that Mary fed the cat
• (I wondered) if Mary fed the cat
• (I wondered) who Mary fed

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Basic clause structure 2

• Force in root clauses
• Ø Mary will feed the cat
• Will Mary __ feed the cat
• Who will Mary __ feed __
• Forming questions requires dislocation

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Some more examples

• loveV, BonzoN ? VP
• loveV BonzoN
• John, VP loveV BonzoN ? VP
• V
• JohnN loveV BonzoN
• V indicates that the construction of the verb
  phrase continues
• Terms Head, complement, specifier

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Selection

• Selection restricts possible combinations
• Syntactic selection
• D selects NP, T selects VP, C selects TP
• Semantic selection
• John loves Mary
• ??The brick loves Mary
• John opened the lock/the key opened the lock
• ??Serenity opened the lock

42
Principles of structure building

• Working space Lexicon, assembly line
• i) access (a head) a from the lexicon
• ii) access b from the lexicon or assembly line
  that is selected for by a
• iii) merge a and b as an a-category (b is a
  complement of a)
• iv) put ab back on the assembly line or
• v) access c that is selected for by a
• vi) merge ab and c as an a-category (c is a
  specifier of a)
• vii) put abc back,
• etc. recursion

43
Limitations on operations

• Limited possibilities to disassemble what has
  been put together
• Locality of linguistic operations
• Cycles and Phases
• Surprise
• Constructing a language works best bottom up

44
Basic pattern of linguistic structure X'
structure

• Lexical categories Functional categories
• VP b V' V a TP b T' T a
• NP b N' N a DP b D' D a
• AP b A' A a CP b C' C a
• PP b P' P a etc.
• XP
• Specifier X'
• X0 Complement

45
X-structure a matter of convenience

• Lexical categories Functional categories
• V b V V a T b T T a
• N b N N a D b D D a
• A b A A a C b C C a
• P b P P a etc.
• X
• Specifier X
• X Complement

46
X-structure a matter of convenience

• Merge a, b ? a, a,b substitution
• Merge a,b ? lta,agt a,b adjunction
• X, Y, X, X,W
• SpecifierY X, X,W
• X Comp W

47
Dependencies

• A fundamental property of all human languages
  Dependency Relations.
• Local Semantic roles, Case, agreement, category
  selection
• (functional-lexical D-NP, T-VP)
• Non-local dislocation, anaphors, pronominals
• Dependencies are always constrained ? must be
  obeyed in putting expressions together

48
Semantic roles 1

• - agent, e.g. John in John hit the ball
• - instrument, e.g. a knife in John cut the salami
  with a knife
• - cause, e.g. the wind in the wind opened the
  door
• - experiencer, e.g. John in John worried about
  his health,
• - goal (sometimes benefactor) e.g. Mary, in John
  gave Mary a book, Boston, in John went to Boston
• - patient, e.g. the cat in John kicked the cat,
  or the couch in John moved the couch
• - source, e.g. the police, from prison in Max
  escaped the police /from prison
• Agents and experiencers are animate
• Causes, instruments, etc. need not be.

49
Semantic roles 2

• Reinhart (2002)
• The computational system can only see themativc
  information that has passed through a limited
  channel
• Two binary formal features
• /- m, /- c
• m mental involvement
• c causation

50
Local dependencies

• Selection conceptual (semantic-roles)
• ??Sincerity admires John
• Subcategorization formal/arbitrary
• John loves Mary Jan houdt van Marie
• Case
• He saw her again her saw he again
• Agreement
• You love(s) Fluffy These/this boys

51
Verbs show role-alternations Passive

• John discovered (Mary)
• Mary was discovered (by John)
• John fed the cat
• The cat was fed by John
• John gave (Mary) (a book)
• Mary was given a book (by John)
• Systematic combination of three factors
• i) the verb is in participial form
• ii) there is a form of to be as a passive
  auxiliary
• iii) the object shows up in subject position ?
• dislocation (a general phenomenon in language)

52
Putting expressions together

• (I saw) John feed Fluffy (bare VP)
• (I expect) John to feed Fluffy (to VP but!!
  mismatch)
• John will feed Fluffy (TVP, T takes over, but!!
  mismatch)
• John feeds Fluffy (TVP, but !! mismatch)
• TP
• T'
• T VP
• will/to V'
• John V
• feed Fluffy

53
Rearranging elements

• (I saw) John feed Fluffy (bare VP)
• ------ John to (John) feed Fluffy
  (toVPrearrangement)
• John will (John) feed Fluffy
  (TwillVPrearrangement)
• John (-s) (John) feeds Fluffy (T s VP
  rearr.)
• TP
• John T'
• T VP
• to/will/-s V'
• (John) V
• feed Fluffy

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Dislocation 1

• Dislocation Mismatch between positions of
  interpretation and position of realization
• Metaphorical term Movement
• Dislocation/Movement expresses Double Duty
• Essence One and the same element is active in
  two (or more) positions and realized in only one
  position.

55
Dislocation 2

• The specifier of T must be filled
• it will rain
• there arrived a man
• Dual use re-use an element from the structure
• TP
• He T'
• T VP
• will V'
• (he) V
• love Mary

56
Adding Force CP 1

• (I thought) that TP John would love (her)
• (........) CP declarative marker that
• ---- C'
• C TP
• that T'
• John T VP
• would V'
• (John) loveV her

57
Expressing questions CP 2

• (Mary wondered) CP ifC TP John would love her
• (........) CP Question marker added
• ---- C'
• C TP
• if T'
• ltwhgt John T VP
• would V'
• (John) loveV her

58
Expressing Questions CP 3

• (Mary wondered) whom TP John would love
• (........) CP
• whom C'
• C TP
• - T'
• John T VP
• would V'
• (John) loveV (whom)

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How to express dislocation?

• (Mary wondered) whomi TP John would love -
• (........) CP
• whomi C'
• C TP
• - T'
• John T VP
• would V'
• (John) loveV -

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The canonical trace notation

• (Mary wondered) whomi TP John would love ti
• (........) CP
• whomi C'
• C TP
• - T'
• John T VP
• would V'
• (John) loveV ti

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The status of traces

• What do traces represent?
• What kind of elements are they?
• Are they needed? If so, why?
• Answer in Minimalist Program
• Double duty can be expressed without an
  additional element in the theory
• Copies can do the same job ?
• Merge Internal/External ? traces only for
  convenience

62
Questions in root clauses

• Whom did John love t
• CP
• whomh C'
• C TP
• didj Johni T'
• T VP
• tj V'
• ti V th
• love

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Clausal layers

• Predicational core verb arguments
• Tense/mood layer coordinates for evaluation
• Force layer (C) assertion, question, command
• Movement enables one and the same element to be
  used in more than one layer
• Whomi did John love ti
• Whom argument of love in predicational core
  signals question in Force domain
• Did carrier Tense in Tense/mood layer
  identifies C in Force domain

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Dislocation General

• Formally encoded by requirements of feature
  checking
• A head (such as C, T, etc.) looks down into the
  structure to which it has been attached, and
  probes for a goal - an element that carries a
  feature matching its requirements and attracts
  it
• Empirical questions
• Is all dislocation triggered by probe-goal
  relations?
• Requirements of information structure may
  suffice.
• Do all probe-goal relations result in
  dislocation?
• The existence of a probe-goal relation (AGREE)
  is necessary, but not sufficient

65
Wh-movement Question formation

• Instruction
• Merge a question word (Wh-word) in the position
  of which you wish to elicit the value, and link
  it to the Force layer of the clause by moving it
  there
• A very similar operation works in relatives

66
Wh-movement as an interpretive dependency

• The interpreter must crucially know
• i) a wh-element up front of the clause is part
  of the Force layer, and must therefore be
  interpreted as signalling a question
• ii) a wh-element up front must be related to a
  gap (a trace, silent copy, etc.) and his
  computational system must be able to figure out
  where that gap is.

67
Some questions and relatives

• Wh-movement Movement to a Force position
  (non-argument no semantic role, no Case)
• Question formation and relativization
• I wonder CPwhich mani ti read the book
• I wonder CPwhich booki the man read ti
• Subject versus object relatives
• I admired the man CPwhoi ti wrote the book
• I admired the book CPthati the man wrote ti

68
Wh-movement illustrations

• a. (John was wondering) whom he loved
• b. (John was wondering) --- he loved whom
• c. (John was wondering) whomi he loved ti
• Possible over an unbounded domain
• Whomi did you say that Bill told Mary that he
  was willing to bet a million bucks that she
  never considered to promise Cindy she would
  leave ti alone?

69
Structure and processing

• What would you predict about the representation
  of
• functional structure versus
• core predication
• by subjects with reduced processing capacity?
• They will be selective functional structure
  affected

70
Language comprehension (Cutler Clifton)
71
Common denominator of processing models

• Modularity
• language results from a number of specialized
  components responsible for different aspects of
  language representation/processing
• Major divisions
• form (syntax) vs. meaning (semantics) vs. use
  (discourse)
• Hypothesis
• Syntax, meaning, and use are subserved by
  different types of processes
• Investigation tool
• Dissociability of processing mechanisms

72
Evidence Neurolinguistics

• The study of brain language relationships
  through neurological deficits
• Prime example aphasia
• A deficit in producing and understanding spoken
  and written language due to focal brain damage in
  persons who have gone through normal language
  development.(Prins Bastiaanse 1997)
• Incidence
• approx. 6000 new cases per year in NL
• approx. 20.000 patients in NL
• Founding fathers of aphasiology
• Paul Broca
• Carl Wernicke

73
Paul Broca (1824-1880)

• 1861 Broca discovers in a post mortem study
  (Monsieur Tan) that speech/language (production)
  is associated with the foot of the 3rd
  convolution of the frontal lobe
• Brodmanns areas 44 45
• today, we call this Brocas area

74
Mr. Tans brain
75
Carl Wernicke (1848-1904)

• 1874 Wernicke discovers a second cortical area
  connected to language the posterior part of the
  uppermost temporal gyrus (STG), right behind the
  primary auditory cortex
• Brodmanns area 22
• today Wernickes area

76
Brodmanns areas
Korbinian Brodmann (1868-1918)
77
Aphasia syndromes
78
Wernicke-Lichtheim-Geschwindt
79
Agrammatism and the CP-layer

• Question production in agrammatism The Tree
  pruning hypothesis, Naama Friedman, Tel Aviv
  University, Brain and Language 80, 160-187
• Patients Hebrew versus English speakers with
  similar brain injuries
• Variable Wh-questions versus Yes-no Questions
• English both involve C
• Hebrew only Wh-questions involve C

80
Observations and results

• Wh-questions (similar for Hebrew and Arabic)
• (1) H Miri mecaryeret portret
• E Miri draws a portrait
• H Mai Miri mecayeret ti Wh moves to C
• E What (does) Miri paint Wh moves to C
• Yes/no questions
• Usually differ from declarative sentences in
  intonation only ? no involvement of C
• (3) H Miri mecaryeret portret
• E Does Miri draw a portrait T moves to C
• Result In Hebrew only Wh-questions were
  affected in English both were
• ? structure is reflected in pathology

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Explanation

• Tree pruning hypothesis The highest nodes of the
  syntactic tree are inaccessible in agrammatism
• CP
• whh C'
• C TP
• Tj Mirii T'
• T VP
• tj V'
• ti V th
• draw
•  
•  
• VP
•  
• DP V'
• V DP

82
Dependencies Passive

• Movement into the subject position
• T'
• T VP
• was V'
• V' DP chased the mouse
• Passive morphology
• no semantic role to the subject
• no case for the object
• ? double use of the object ? requirement to move
  into the Tense system

83
Dependencies Passive 2

• Movement into the T-system
• TP
• the mousei T'
• T VP
• was V'
• V' DP chased ti
• Passive morphology to interpreter
• do not assign standard semantic role to the
  subject
• look for a gap
• assign to subject the role that otherwise would
  go to the gap

84
Reversible and non-reversible passives

• Non-reversible
• The apple was eaten by John
• Reversible
• The dog was chased by the cat
• The ability to process passive morphology is a
  prerequisite for the correct interpretation of
  reversible passives

85
Passives and the language system

• The prerequisite of being able to accurately
  process morphology is naturally satisfied in the
  mature and intact language system, but it need
  not be met in an immature or impaired system.
• Both for young children and for patients with
  certain types of language impairment this
  condition may not be met, and hence such speakers
  may have considerable problems with reversible
  passives.

86
Passives and agrammatism

• A Restrictive Theory of Agrammatic Comprehension,
  Yosef Grodzinsky, Tel Aviv University and Aphasia
  Research Center, Boston University School of
  Medicine, Brain and Language 50, 27-51

87
Observations

• (1) Above chance performance
• The girl pushed the boy
• (2) Chance performance
• The boy was pushed by the girl
• Hypothesis syntactic movement yields problems
• More precisely
• - traces are invisible to semantic role
  assignment
• What do subjects do?

88
Strategy

• The agent role is the most prominent role in a
  hierarchy of semantic roles
• Subjects use this for an auxiliary strategy
• Assign the agent role to the leftmost NP of the
  clause as a default role

89
Result

• TP
• T'
• NPi T VP
• the boy was
• V' PP
• V pushed ti by the girl
• The default strategy correctly interpreting the
  by-phrase ? ill-formed interpretation ? guessing

90
A below-chance performance

• Agrammatic role assignment Normal assignm.
• a. The mani is pushing the woman
• agent theme ltagent, themegt
• b. The womani is pushed ti by the man
• agent agent lttheme, agentgt
• c. The mani is hated ti by the woman
• agent experiencer lttheme,
  experiencergt
•  
• c) yields below chance performance, since agent
  wins over experiencer

91
Reversibility in wh-movement

• The ball that the boy is kicking t is red
• The cat that the dog is chasing t is black
• The latter also presents problems for Brocas
  aphasics
• Again the trace deletion hypothesis (Grodzinsky
  et al.) can be adduced Brocas aphasics have
  problems processing traces ? they use a default
  strategy to interpret sentences with traces

92
Some Caveats

• Lesion in Brocas area neither sufficient nor
  necessary to induce syntactic deficits
• Brocas area is not always lesioned in a
  clinically significant Brocas aphasia
• Brocas area can be affected in patients who do
  not display a Broca syndrome most of these
  patients are mildly anomic.
• Severity of morphosyntactic problems in aphasia
  is correlated with the extent of damage in BA 22.
• Also semantic deficits in Brocas aphasia.

93
Disadvantages of patient studies

• damage to neural tissue may not be well
  delineated (in functional terms)
• rather, depends on histological properties or on
  structure of vascular system
• possibility of compensation/adaptation
• aphasic symptoms evolve over time (post onset)
• ? unclear which symptoms (and hence processes)
  are linked to which neural networks

94
Healthy subjects Imaging studies

• PET
• fMRI

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Is Brocas area the syntax center?

• Kaan Swaab 2002, review (Trends in Cognitive
  Sciences)
• perception/comprehension studies subtraction
  method
• paradigms
• complex sentences vs. simple sentences
• sentences vs. word lists
• jabberwocky/syntactic prose vs. word lists/normal
  sts
• syntactic violations vs. correct sentences

98
4. Syntactic violations

• trees can grew vs trees can eat
• assumptions
• more work in violation cases
• results
• syntactic anomalies ? NO activation of Brocas
  area
• sometimes more superior frontal activity (also
  for semantic violations)
• more frontal than temporal activation in with
  syntactic errors
• caveat
• syntactic violations may have semantic
  consequences

99
Syntactic violations
100
Wheres syntax in the brain?

• Overview Kaan Swaab 2002, review (TICS)
• Brocas area
• NOT necessarily involved in syntactic processing
• more activation with more working memory demands
• other areas associated with syntax
• anterior temporal lobe
• anterior parts of BA 21, 22
• superior middle temporal gyri
• not only Left Hemisphere!

101
Brocas area

• is an excitable piece of tissue!(David
  Poeppel, p.c.)
• activated by (i.a.)
• word/syllable lists (memory)
• semantic tasks
• phonological tasks
• music perception

102
Suggestions (KS 2002)

• Middle/superior temporal lobe
• lexical processing (activating semantic/syntactic,
  phonological features of words)
• Anterior temporal lobe
• combining activated information
• Brocas area
• storing non-integrated materials
• Right hemisphere
• prosody
• ambiguity
• discourse
• error detection

103
What is syntactic processing?

• structure building
• grouping words into phrases, phrases into
  sentences
• determining dependencies
• what goes with what?

104
dislocation/movement

• In structural terms
• an element is doing double duty by having two
  copies in the structure only one of these is
  spelled out phonetically (ie., has an audible
  form)
• in processing terms
• the processor has to recognize an empty spot at
  the location of the object NP and infer which
  noun phrase can be connected to it.

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Electro-magnetic signals

• EEG/ERP
• (MEG/ERF)

• Different signatures for syntactic and semantic
  processing?
• Autonomy of syntactic processing?

106
EEG
107
ERP (Bressler 2002)

• The physiological basis of the cortical ERP
  Fields of potential generated by interacting
  neurons. Field potentials result from the summed
  extracellular currents generated by electromotive
  forces (EMFs) in the dendrites of synchronously
  active cortical neurons. The EMFs, arising from
  synaptic activation of postsynaptic ion channels,
  circulate current in closed loops across the cell
  membrane and through the intracellular and
  extracellular spaces. Summed closed-loop currents
  generated by an ensemble of neighboring neurons
  flow across the external resistance to form the
  local ensemble mean field potential.
• The event-related potential (ERP) Neural signal
  that reflects coordinated neural network
  activity. The cortical ERP provides a window onto
  the dynamics of network activity in relation to a
  variety of different cognitive processes at both
  mesoscopic and macroscopic levels on a time scale
  comparable to that of single-neuron activity.
• Good Temporal resolution
• Bad Spatial resolution

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Event-Related Potentials
ERP
109
ERP language N400
Kutas Hillyard 1980
110
N400

• negative(-going) component
• peak latency around 400ms
• bi-lateral slightly posterior distribution
• N400 effect (amplitude modulation)
• (mis)match of word meaning with preceding context
• semantic priming

111
P600/SPS
Osterhout Holcomb 1993 Hagoort, Brown
Groothusen 1993
112
P600

• positive(-going) deflection
• peak latency around 600ms
• bilateral, centro-parietal distribution
• grammatical anomalies
• ambiguities that are resolved in a dispreferred
  way
• long-distance dependencies

113
ERP Early Left-Anterior Negativity
add picture
114
ELAN

• negative(-going) deflection
• peak latency around 200ms
• left anterior distribution
• grammatical violations, e.g.
• phrase structure
• inflection, function words

115
lexical vs. functional categories

• lexical N, V, A, (P)
• functional Infl, Det, Comp
• agrammatism
• child language
• ERP (ter Keurs et al.)

116
lexical vs. functional categories
negative peak earlier for functional categories
117
What do ERPs signify?

• physiologically synchronous post-synaptic
  activation of several hundreds of thousands of
  radially oriented pyramidal cells
• functionally No idea!
• the brain (groups of neurons) responds in a
  particular, consistent way to particular stimuli

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Interim conclusion wrt ERPs

• N400, P600 and (E)LAN differ in
• polarity
• latency
• distribution
• eliciting conditions
• P600, (E)LAN syntactic problems
• N400 semantic problems
• ? different generators, i.e., different neural
  processors dealing with syntax and semantics.

119
The big picture? (Friederici et al)
120
Relating Neurocognition and Linguistic
Architecture

• A neuro-cognitive contrast between linguistic
  computational mechanisms and the lexicon ((Ullman
  2001)
• the computational system procedural memory
• the lexicon declarative memory

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Linguistic Theory and Neural Activity

• What can we expect?
• Very abstractly
• Match between properties of derivations and
  processes
• in production or comprehension?
• Match at the architectural level
• differences between modules involved in a mental
  
• computation reflect differences in neural
  activity