Neurolinguistics: Brain and Language

Brain and language

Brain and language

• Neurolinguisgics: it is concerned with understanding how language is represented and processed in the brain.

• Brain science or neuroscience is concerned with understanding how the breadth and depth of human experience is coded in the brain matter.

Interesting brain facts!

• About 1.4 kg (2% of body weight) mass of fat & protein with 75% water content

• W = 140 mm, L = 167 mm, H = 93 mm. Left hemisphere is larger than the right

• 40% grey matter (outer covering: cerebral cortex) 60% white matter (myelinated fiber tracts traveling to & from the cerebral cortex)

• 100 billion neurons (166 times human population & would take 171 years to count!

• stops growing at 18

• 12 pairs of cranial nerves & 31 pairs of spinal nerves

Parts of the brainKeep in mind there are two distinct sides with different functions

The Brainstem(Pathway to the Body)

• Base of brain• Unconscious work• Autonomic

functions, e.g., survival, breathing, body functions, etc.

The Cerebellum(Balance)

• ‘little brain’• Large in size• 11% of brain’s

weight• Center of balance

The brain has 4 areas called lobes

• Frontal

• Parietal

• Temporal

• Occipital

The Frontal Lobes(Problem Solving)

• Largest part• Moves your body• Highly developed• Forms your

personality

The Parietal Lobes(Touching)

• Two major divisionsAnterior and posterior

• Senses hot and cold, hard and soft, and pain

• Taste and smell• Helps integrate the

senses

The Temporal Lobes(Hearing)

• Processes auditory stimuli

• Subdivisions into• Wernicke’s Area

(associated with speech comprehension)

• Broca’s Area(associated with speech production)

The Occipital Lobes (Seeing)

• Located at lower central back of brain

• Processes visual stimuli

Taking sides….two sides that is!

• Two sides or hemispheres of the brain: LEFT and RIGHT

• We have two cerebral hemispheres connected by the corpus callosum

• This is a bundle of nerves that allows each side of the brain to communicate with each other

• Each side of the brain processes things differently

• It is an outdated assumption that “artsy” type people are right-brained

How the two sides process information!

Left Brain

• Logical

• Sequential

• Rational

• Analytical

• Objective

• Looks at parts

Right Brain

• Random

• Intuitive

• Holistic

• Synthesizing

• Subjective

• Looks at wholes

Left Hemisphere

• processes things more in parts & sequentially

• recognizes positive emotions

• identified with practicality and rationality

• understands symbols and representations

• processes rapid auditory information faster than the right (crucial for separating the sounds of speech into distinct units for comprehension)

• is responsible for language development. It develops slower in boys, that is why males usually develop more language problems than females

Right Hemisphere

• recognizes negative emotions

• high level mathematicians, problem solver like chess playing

• the “non-verbal” side

• responds to touch & music (sensory)

• intuitive

• responsive to color & shape

• emotional & creative

Taking sides….what information the two sides recognize!

Left Brain

• Letters

• Numbers

• Words

Right Brain

• Faces

• Places

• Objects

Aphasia

• Aphasia is defined as an acquired impairment in the use of language due to damage to certain parts of the brain

• This damage could be caused by injury, stroke, or seizure

• The language deficits include difficulties in language comprehension and execution

Major Types of Aphasias

All aphasias can be classified into two groups• Non-fluent aphasias – Difficulty producing fluent, articulated, or self-

initiated speech• Fluent aphasias – The inability to understand the language of others

and the production of less meaningful speech then normal

Non-Fluent Aphasias

• Broca’s aphasia– This type of aphasia manifests with difficulties

initiating well-articulated conversational speech– The language that is produced is slow, labored, and

ungrammatical, which means words like a, an, or the and verb tense is left out of their speech

– This aphasia is produced by damage to Broca’s area of the brain

The speech is very halting. Patients have great difficulty in accurately producing the needed phonemes to say a word.

(a) It's hard to eat with a spoon(b)…. har eat….wit….pun

Broca’s aphasia

Broca’s aphasia as a syntactic disorder

(a) It's hard to eat with a spoon(b)…. har eat….wit….pun

Omission of "little words" are often called function words, and the speech is characterized as “telegraphic speech”. One possible account of the speech of Broca's aphasics is that it results from an economy of effort.


Broca's aphasics will not always be able to determine which ones are grammatical and which one are not:

A) The boy at it up.b) The boy ate up itc) Boy ate it upd) The boy ate up the cake


a)The mouse was chased by the catb)The dog was chased by the catc)The cat was chased by the mouse

Most Broca's aphasics have complete understanding of what they should say, but find themselves unable to say it.

More Types of Non-Fluent Aphasia’s

• Global aphasia – As the name suggests, this type of aphasia is

characterized by a severe depression of all language functioning

– The people with this affliction have poor language comprehension and speak in slow, labored jargon

– This aphasia is caused by damage around and to Broca’s and Wernicke’s areas of the brain

Types of aphasiaFluent aphasia

Fluent aphasics have no difficulty producing language, but have a great deal of difficulty selecting, organizing, and monitoring their language production.

The most important type of fluent of aphasia is called Wernicke's aphasia. The syndrome is named after the German physiologist Carl Wernicke.


This type of aphasia was associated with a lesion in the temporal lobe.


Wernicke's aphasics are generally unaware of their deficit.

Their speech typically sounds very good: there are no longer pauses; sentence intonation is normal; function words are used appropriately; word order is usually syntactically correct.

The problem is that the patient rarely makes any sense.


The following is a conversation between an examiner E and a Wernicke's patient (P):E: How are you today Mrs. A?P: YesE: Have I ever tested you before?P: No, I mean I haven'tE: Can you tell me what your name is?P:No, I don't I… right I'm right now hereE: What is your address?P: I cud /kd/ if I can help these like this like you know… to make it. We are seeing him. This is my father.


This semi-random selection of words and short phrases very few real words of the language is termed jargonaphasia.

Wernicke's aphasia is primarily a comprehension deficit.

Other Interesting Facts About Aphasia

The handwriting of a person with an aphasia reflects their speech impediment.

There was an experiment done where people with Broca’s and Wernicke’s aphasias were presented with a picture and then asked to

write down a description of what they see in the picture.

This is the picture

A patient with Broca’s aphasia wrote this

Notice the use of very few words, but the words do make some sense

A patient with Wernicke’s aphasia wrote this

Notice here that there are many, less forced, words, but they don’t make much sense. Also because they’re

not struggling to find their words, the handwriting is better.

Education

Neurolinguistics: Brain and Language