Language

References:

Kutas M., Hillyard SA., Reading Senseless Sentences: Brain Potentials Reflect Semantic Incongruity, Science, Vol 207, pp.203-205, 1980

Price, C., The Anatomy of Language: Contributions from Functional Neuroimaging, Journal of Anatomy, Vol. 197, pp. 335-359, 2000

Bookheimer, S., Functional MRI of Language: New approaches to understanding the cortical organization of semantic processing, Annual Reviews Neuroscience, vol 25, pp.151-188, 2002

Demonet JF, Thierry G, Cardebat D., Renewal of the Neurophysiology of Language: Functional Neuroimaging, Physiological Reviews, Vol 85, pp.49-95, 2005

Marien P, Engelborghs S, Fabro F, DeDeyn PP, The Lateralized Linguistic Cerebellum: A review and a new hypothesis, Brain and Language, Vol 79, pp.580-600, 2001

Wierenga C., Maher LM, Moore AB, White KD, McGregor K, Soltysik D, Peck KK, Gopinath K, Singletary F, Gonzalez-Rothi L, Briggs R, Crosson B, Neural Substrates of Syntactic Mapping Treatment: An fMRI study of two cases, Journal of the International Neuropsychological Society, Vol 12, pp.132-146, 2006

Evolutionary Anatomy of the Primate Cerebral Cortex, Eds. Dean Falk, Kathleen Gibson, Cambridge University Press, 2001

The Cognitive Neurosciences III, Ed. Michael Gazzaniga, MIT Press, 2004, Chapter 1: What is it like to be human, Todd Preuss

Early studies in morphology

Lateralization: Functional specification of local areas wtihin hemispheres

* Hand bump area in Chimp, but not macaque

* Handedness: Observed in chimps, but equally distributed in entire population.

In humans, for 95% of right handers, language is in LH (for 70% of left handers, language is in LH)

Asymmetry of the planum temporale and lateralization

Planum temporale (PT)

Gazzaniga

PT: Area of Sylvian fissure posterior to the Heschl's gyrus (primariy auditory cortex)

Structural asymmetry of the PT

Falk & Gibson

Structural asymmetry of the PT

present in chimp and human: L>R

Falk & Gibson

Early studies in function

First neuroimaging study in language

Kutas & Hillyard, Science, 1980

First neuroimaging study in language

Kutas & Hillyard, Science, 1980

Note the difference from oddball (P300)

attention

N400 language comprehension

Evolutionary perspective

As brain gets bigger,more cortical areasmust be added

For Ex:More than 50 Broadmann areasin human, but about 20 in Old world monkeysGazzaniga

Corbalis' explanation for evolution of language: Chimps are quadripedal. Transfer of humans to bipedalism was a huge step. Humanoids started to roam, and needed speech to communicate to free hands from gesturing (--->complex tool making)

Area for mirror neurons andgesturing, both in chimps andhumans

Localization of Language

Demonet, 2005

* RH is activated for non-semantic sounds, LH for words

Price, 2000

19th century model of languagefor single words

Motorimage

of speech

Auditoryimage

of speech

Auditoryinput

(Heschl'sgyrus)

Speechgeneration

Visualwordforms

3 types of memory needed for language: (C. Price)

1. Phonological (sounds)

2. Ortographic (spelling)

3. Semantic (knowledge)

Inputs:

Auditory

Visual

Tactile (Braille)

Output:1. Self-initiated2. Stimulus driven (response to written on heard words)

Basal temporal language area: BA19, BA37, BA20

Demonet, 2005

Semantic knowledge

Price, 2000

Concept centre:

= semantic categories

INPUTS

OUTPUTS

Price, 2000

20th century model of languagefor single words

based on behavioral data

Semanticcategories

Price, 2000

Not accounted for, in these models:

Price, 2000

basal temporallanguage area

2 routes:

for language

route1route2

Damage in route1: surface dyslexia

Damage in route2: phonological dyslexia

Newly proposed modelwhich accounts fordyslexia

Development of the proposed model: word repetition

(Posterior IFG)

Note bilateral activity !!!

Development of the proposed model: speech input/output

(word deafness occursif bilateral lesions presentin these areas of PAC)

critical speech production regionword retrieval:

picture namingverbal fluency

Development of the proposed model: reading

Accessing semanticsin sentences

Development of the proposed model: repetition versus reading

Development of the proposed model: semantic knowledge

angular gyrus:semantic processing

Price,2000

Specialization areas in IFG: (Bookheimer, 2002)

* There is functional heterogeneity among Broca's aphasics in terms of impairments

* Three dissociated areas in L IFG are found:1. Anterior IFG = retrieval of semantic information 2. Middle IFG = syntax (complexity α WM load)3. Posterior IFG = phonology (sensorimotor encoding of auditory input)

* Example tasks: Given two sentences with a change in:- 1 word (semantic task): he went to the store vs he went to the school- word order (syntactic task): the west of the cinema is store store is the west of the cinema find if two sentences have the same meaning

- Active/Passive: A lion was fatally attacked by the tiger. or The tiger fatally attacked the lion Question: Which animal died ? (passive sentence is difficult for aphasics)

- Given a word break it down in to phonemes (phonologic task)

Bookheimer,2002

Non-language roles proposed for IFG:

* Studies indicate area 44 in humans is similar to area F5 in monkeys which contain mirror neurons

* It is also thought that imitation is an essential step for developing language

* BA 44 activates in humans when they imagine to observe a movement

* Hence BA 44 is not specialized for just language but also for imitation of complex movements, which embodies speech planning

* In addition, IFG activates for some tone discrimination tasks as well

* This indicates that the phonological role assumed by IFG is not speficic to language

Right Hemisphere

* Judging whether a sentence contains metaphors (ex: Investors were squirrels collecting nuts) caused greater activations in R IFG, and R post. sup. temp. gyrus. Same RH areas activated in addition to areas inLH, when subjects tried to determine the moral lesson of a passage

* In one study, passages are presented with or without titles. The passages indirectly used the title to convey information, without the titles, passages didnot make sense. Extensive RH activity was observed in all language areasfor passages without titles

* LH is powerful for tracking sequential logic, but RH is powerful for keepinga holistic understanding of a talk (topic maintanence)(seq logic: If A is B and B is C then A is C) (top. maint.: Dou you believe in angels? Yes I have my own angel)

* In a few studies, R IFG activated for processing sentences with prosody versusneutral sentences

* From these studies, it seems RH has a critical role in language comprehension and a global understanding of semantic context

Bookheimer, 2002

Bookheimer,2002

RL

?

Cerebellum

Lateral cerebellum sends to and receives from contralateral BA 6,44, 45 through thalamus and pons respectively

In word generation studies R lateral cerebellum which connects to L PFCactivates consistently

In patients with R cerebellar damage there are deficits in semantic wordgeneration, phonological generation, and syntactic processing

It is speculated that cerebellar damage causes diminished or abolished function of remote language zones due to reduced input throughcerebellocortical pathways (diaschisis)

Marien, 2001

Marien, 2001

Patient studies

Infarct in LH

rehabilitation

Active sentences Passive sentences

Chronic, non-fluent aphasia,53. months after onset

Applications of neuroimaging in aphasia patients:Sentence production

C. Wierenga, 2006

Sentence production fMRI

fMRI:ON - sentence production wrt given picture as in learning setOFF- watching non-sense picts

C. Wierenga, 2006

n=15 autism adults, 15 control

Absence of Planum temporale asymmetry

Rojas

Worthy of note

Task:* Silently generate words for a given category (no speech)* Auditory stimuli* Example Category: “farm animals”

Paradigm:* Block* Timing:17.5 sn on & off (rest)* Repetitions: 6

Subjects:* 15 M, 13 F students* Age: 26.4 (sd:7.1)

Data collection:* 1.5T GE MR scanner* fMRI: Nine 6.5 mm thick slices, 64 images each gradient echo spiral scan

Analysis:AFNI (MCW)

Problem of precise localization in a word generation study

Results obtained with LOFA

Overall activityAnatomy CS/PCS activity

Wit

h P

CS

Wit

hou

t P

CS

* Nüfusun %75 inde PCS var

* PCS var ise CS kelime üretmede yeralmazActivity is located in PCS, whenever there is a PCS present B. Crosson, 1999

same areaaftersmoothingin 28 subj