LANGUAGE AND COMMUNICATION

COMMUNICATION IN LOWER ANIMALS

Beas have complex sign language for direction of food

Singing birds share same gene FOXP2 expressed in basal ganglia of human.

DO APES HAVE LANGUAGE?

Apes can learn limited signs, understand and speak

Great apes have similar brain area like human to support language

LEARNING TO SPEAK

THE DEVELOPMENT OF LANGUAGE: A CRITICAL PERIOD IN HUMANS

 A critical period for learning language is shown by the decline in language ability (fluency) of non-native speakers of English as a function of their age upon arrival in the United States

BRAIN AS HOLLOW ORGAN : NEMESIUS (CIRCA 320),

The cerebral ventricles were supposed to be responsible for mental operationsLanguage was not represented

LANGUAGE AREA IN PHRENOLOGY

BROCA’S APHASIA

Autopsy of a patient who could understand, with normal speech apparatus but could not speak or write a sentence.

Only articulate sound he could make was “tan”

After autopsying eight similar patient with lesion in the left frontal lobe

He made a famous statement that “we speak with the left hemisphere”

Paul Broca 1861

BROCA’S AREA

Area 44 (the posterior part of the inferior frontal gyrus) seems to be involved in phonological processing and in language production as such; this role would be facilitated by its position close to the motor centres for the mouth and the tongue.Area 45 (the anterior part of the inferior frontal gyrus) seems more involved in the semantic aspects of language. Though not directly involved in accessing meaning, Broca’s area therefore plays a role in verbal memory (selecting and manipulating semantic elements).

CARL WERNICKE

Ten years later, Carl Wernicke, a German neurologist, discovered

another part of the brain, this one involved in understanding

language, in the posterior portion of the left temporal lobe.

People who had a lesion at this location could speak, but their

speech was often incoherent and made no sense.

WERNICKE’S AREA

WA lies superior temporal gyrus, in the superior portion of Brodmann area 22 has 3 subdivision

The first responds to spoken words (including the individual’s own) and other sounds.

The second responds only to words spoken by someone else but is also activated when the individual recalls a list of words.

The third sub-area seems more closely associated with producing speech than with perceiving it

WERNICKE - GESHWIND MODEL: REPEATING

To repeat a word that is heard, we can hypothesize that information must first get to the primary auditory cortex. From the primary auditory cortex, information is transmitted to the posterior speech area, including Wernicke's area. From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex to produce the utterance

WERNICKE - GESHWIND MODEL: READING ALOUD

To speak a word that is read, information must first get to the primary visual cortex. From the primary visual cortex, information is transmitted to the posterior speech area, including Wernicke's area (via the angular gyrus, which mediates between visual and auditory aspects of language). From Wernicke's area, information travels to Broca's area, then to the Primary Motor Cortex.

VARIATIONS IN THE SIZE AND POSITION OF BROCA’S AREA AND WERNICKE’S AREA

CORTICAL MAPPING OF THE LANGUAGE AREAS IN THE LEFT CEREBRAL CORTEX DURING NEUROSURGERY

LANGUAGE-RELATED AREAS IN THE HUMAN BRAIN.

The implementation system is made up of several regions located around the left sylvian fissure. It includes the classical language areas (B = Broca's area; W = Wernicke's area) and the adjoining supramarginal gyrus (Sm), angular gyrus (AG), auditory cortex (A), motor cortex (M), and somatosensory cortex (Ss). The posterior and anterior components of the implementation system, respectively Wernicke's area and Broca's area, are interconnected by the arcuate fasciculusThe mediational system surrounds the implementation system like a belt (blue areas). The regions identified so far are located in the left temporal pole (TP), left inferotemporal cortex (It), and left prefrontal cortex (Pf). The left basal ganglia complex (not pictured) is an integral part of the language implementation system

MARSEL MESULAM MODEL OF LANGUAGE 1980

Simple language task like rhyming year, days of week require Motor and Premotor area Hearing a word primary unimodel auditory cortex superior and anterior temporal lobe Unimodel area send to

Paralimbic system, for long term memory and emotional system.

Posteriorsuperior temporal sulcus for meaning.

The triangular and orbital portions of the inferior frontal gyrus also play a role in semantic

processing. Two classical epicenters (B+W) still work for semantic processing

LANGUAGE RELATED AREA OF LEFT BRAIN PET

PET SPEAKING TASK (NAMING)

GESCHWIND’S TERRITORY

the inferior parietal lobule is connected by large bundles of nerve fibres to both Broca’s area and Wernicke’s area.

Information might therefore travel between these last two areas either directly, via the arcuate fasciculus, or by a second, parallel route that passes through the inferior parietal lobule.

The inferior parietal lobule is one of the last structures of the human brain to have developed in the course of evolution

INFERIOR PARIETAL LOBULE AND LANGUAGE

The supramarginal gyrus seems to be involved in phonological and articulatory processing of words, whereas the angular gyrus (together with the posterior cingulate gyrus) seems more involved in semantic processing. The right angular gyrus appears to be active as well as the left, thus revealing that the right hemisphere also contributes to semantic processing of language. 

INSULA IS IMPORTANT FOR PLANNING OR COORDINATING THE ARTICULATORY MOVEMENTS

A. Lesions of 25 patients with deficits in planning articulatory movements were computer-reconstructed and overlapped. All patients had lesions that included a small section of the insula, an area of cortex underneath the frontal, temporal, and parietal lobes. The area of infarction shared by all patients is depicted here in dark purple.B. The lesions of 19 patients without a deficit in planning articulatory movements were also reconstructed and overlapped. Their lesions completely spare the precise area that was infarcted in the patients with the articulatory deficit.

AREA 24: INITIATION AND MAINTENANCE OF SPEECH

They are also important to

attention and emotion and thus can

influence many higher functions. Damage to these areas does not cause an aphasia in the proper sense but impairs the initiation of movement (akinesia) and causes mutism, the complete absence of speech. Mutism is a rarity in aphasic patients and is seen only during the very early stages of the condition. Patients with akinesia and mutism fail to communicate by words, gestures, or facial expression. They have an impairment of the drive to communicate, rather than aphasia.

HANDEDNESS AND LANGUAGE

LATERALIZATION OF LANGUAGE: WADA TEST

SPLIT BRAIN EXPERIMENT

THE BRAIN’S ANATOMICAL ASYMMETRY

 MANUAL “BABBLING” IN DEAF INFANTS RAISED BY DEAF, SIGNING PARENTS COMPARED TO MANUAL BABBLE IN HEARING INFANTS

Babbling was judged by scoring hand positions and shapes that showed some resemblance to the components of American Sign Language. In deaf infants, meaningful hand shapes increase as a percentage of manual activity between ages 10 and 14 months. Hearing children raised by hearing, speaking parents do not produce similar hand shapes

SIGN LANGUAGESigning deficits in congenitally deaf individuals who had learned sign language from birth and later suffered lesions of the language areas in the left hemisphereLeft hemisphere damage produced signing problems in these patients analogous to the aphasias seen after comparable lesions in hearing, speaking patients

THE RIGHT CEREBRAL HEMISPHERE IS IMPORTANT FOR PROSODY AND PRAGMATICS

1. Prosody refers to the

intonation and stress with

which the phonemes of a

language are pronounced

2. Understand organization

of discourse: Signs that

establish the context for a

communication,

3. To understand non

literal language, irony

or metaphors

Woman deciding whether orNot certain words rhyme.

WOMEN AND LANGUAGE

Females’ speech is more fluid: they can pronounce more words or

sentences in a given amount of time

Women have the reputation of being able to talk and listen while doing

all sorts of things at the same time,

Men supposedly prefer to talk or hear about various things in

succession rather than simultaneously.

Women language is more widespread in both hemisphere while in men

more left lateralized (Brain scan studies)

Women also have more nerve fibres connecting the two hemispheres

of their brains, which also suggests that more information is exchanged

between them.

The males’ higher levels of testosterone, which delays the

development of the left hemisphere

4 times more boys than girls suffer from stuttering, dyslexia, and

autism. 

LANGUAGE AREA IN DYSLEXICS

LANGUAGE EVALUATION

1. Spontaneous speech2. Auditory comprehension3. Repetition4. Naming5. Oral reading6. Reading Comprehension7. Writing

SPONTANEOUS SPEECH

1. Ideational counter2. Phrase length3. Articulatory agility4. Gramatic form5. Paraphasias: Literal, verbal, Neologism6. Word finding7. Automatic speech8. Prosody: Recitation, singing

AUDITORY COMPREHENSION

1. Identification of object, action, letter, color, form, number

2. Body part identification3. Command: One step, two step, three step4. Complex ideational material

1. Two sentences (Boat/ Stone sink in water)2. Story -> question

REPETITION, NAMING, READING

Repetition: 1. Word, 2. Phrase, 3. Sentence

Naming:4. Responsive naming (what do we tell time with)5. Visual conform naming: object, action, letter, color,

form, number6. Body part naming7. Animal, vegetable, fruit naming

Oral reading8. Word, 9. Phrase, 10. Sentence

READING COMPREHENSION

Reading comprehension1. Symbol2. Word3. Oral spelling4. Word picture matching5. Reading sentence

WRITING

1. Mechanical: Name, address2. Serial writing3. Primer level dictation: letter, number, word,

sentence and paragraph4. Writing confrontation naming5. Narrative writing

Aphasias

Repetition impaired

Non-fluent

Broca’s Global

Fluent

Comprehension impaired

Wernicke’s Global

Comprehension N

Conduction

Repetition normal

Non-fluent: Anterior

Fluent: Posterior

Subcortical;thalamic and putaminal

APHASIAS

Naming, writing, reading aloud impaired in all types

Writing comprehension poor in sensory aphasias

Copying impaired in Wernicke’s Other Pure Syndromes

Pure word deafness (Auditory word agnosia) Pure word blindness (Alexia) Aphemia Agraphia Anomia Subcortical, thalamic and puaminal aphasias

XENOGLOSIA

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