PHYSIOLOGY

OF

SPEECH

Paul Broca1864 identified the area for speech production

BROCA APHASIA

Karl Wernicke1874 identified the area for speech understanding

WERNICKE APHASIA

Broca areaspeech coding to articulation form„GRAMMAR MACHINE”

Inferior frontal gyrus

Wernicke area speech decoding and understanding of its meaning „LEXICON”

temporal superior gyrus

Temporal gyrus

Fasciculus arcuatusPrimary motor cortex

KEY AREAS IN THE BRAIN AND SPEECH FUNCTIONS

Frontal inferior gyrus

superior temporal gyrus

Occipital lobe

Fasciculus arcuatusPrimary motor cortex

Gyrus angularis

Broca areaspeech coding to articulation form„GRAMMAR MACHINE”

Wernicke area speech decoding and understanding of its meaning „LEXICON”

KEY AREAS IN THE BRAIN AND SPEECH FUNCTIONS

CLASSIFICATION OF APHASIAS

(loss of speech)

Wernicke aphasiaSensory, perceptive, fluent

quick (logorhea) not understandable speech

(also written),

New nonsense words (neologisms),

Words without meaning (paraphasias)

– „speech salad“

Does not understand spoken or written

speech

Lesion of Wernicke area

Broca aphasiaMotor, nonfluent restricted speech

(less complex speech)

Disturbed grammar - „telegraphic speech“

Also written, bad repeating

The patient understands spoken and written

speech

Lesion of Broca area

Transcortical sensory

aphasiaFluent speech, undisturbed

repeating, but does not

understands (like foreign language)

Lesion behind and under

Wernicke area

Transcortical motor aphasiaNonfluent speech, fluent

repeating and understanding of

Spoken and repeated sentences

Lesion before and above

Broca area

BROCA´S APHASIA

• An example of agrammatic speech:

• Ah ... Monday ... ah, Dad and Paul Haney [himself] and

Dad ... hospital. Two .. .ah, doctors ... and ah ... thirty

minutes .. .and yes ... ah ... hospital. And, er,

Wednesday ... nine o'clock. And er Thursday, ten o'clock

.. .doctors. Two doctors ... and ah ... teeth. Yeah, ... fine.

• Another example:

M.E. Cinderella...poor...um 'dopted her...scrubbed floor,

um, tidy...poor, um...'dopted...Si-sisters and

mother...ball. Ball, prince um, shoe...

Broca´s patient Tan

https://www.bing.com/images/search?view=detailV2&id=8DB6E5C35B311A710AEBF6D

B5549734DFA3C782E&thid=OIP.VoH2gr3A72tunn2TNETlEAHaE9&mediaurl=http%3A

%2F%2Fauditoryneuroscience.

WERNICKE´S APHASIA

• The patient in the passage below is trying to

describe a picture of a child taking a cookie.

• C.B. Uh, well this is the ... the /dodu/ of this. This

and this and this and this. These things going in

there like that. This is /sen/ things here. This one

here, these two things here. And the other one

here, back in this one, this one /gesh/ look at this

one.

A photo of the excised brain of a Wernicke's patient http://www.ling.upenn.edu/courses/Fall_2001/ling001/neurology.html

Wernicke's patient

A set of tomographic pictures of a different Wernicke's syndrome brain,

showing a series of horizontal slices. The front of the head is towards the top,

and the dominant (left) side is on the right, so it is as if we are looking at the

brain from the bottom:

http://www.ling.upenn.edu/courses/Fall_2001/ling001/neurology.html

CLASSIFICATION OF APHASIAS

Conductive aphasiaFluent speech, understands, but barely

repeats spoken and written words,

disturbed naming

Damaged connection between the two key

speech areas (Wernicke a Broca)

Global aphasiaNonfluent speech, disturbed understanding

and speech production as a consequence

Of extensive damage in the left hemisphere

(area supplied by arteria cerebri media)

Subcortical aphasiaDisturbed concentration and choice of

Information, speeking in accordance

with breething. Lesion of left thalamic

nuclei

Anomic aphasiaFluent speech, normal

Understanding and

conversation,

Inablity to name people

and objects

Lesion of left angular

gyrus

POSITRONE EMISSION

TOMOGRAPHY (PET)

Injection of

radioactive

2-DG, it is

„ingested“ by

metabolically

active neurons -

phosphorylation

– emission of

positrones –

level of activity

Positron Emission Tomography (PET)Brain metabolic activity during speech

Activity of different brain areas during sensory input (primary and secondary visual and auditory cortex)Basal activity subtracted

Repeating words after subtracting of listening to words = speaking words

Generating verbs to nouns (bread - eat) speaking words subtracted

SPEECH AND ANATOMIC ASSYMETRY

PLANUM

TEMPORALE

Temporal plane in

superior temporal

lobe is identical with

Wernicke area

65% of people have

larger left planum

temporale

(10% right)

SPEECH AND ANATOMIC ASSYMETRY

75% of people has longer left Sylvian fissure (Foundas a spol., 1999)

In most people forms the left Sylvian fissure smaller angle(Hochberg a LeMay, 1975)

FUNCTIONAL ASSYMETRY

OF

BRAIN HEMISPHERES

Speech representation (%)

handedness No Left Bilateral right

righthanded 140 96 0 4

lefthanded 122 70 15 15

(Rasmussen a Milner, 1977) Wada test

handedness (EHI)

N=326

Right hemispheric dominance for speech (%)

righthanded 75 až 100 10

Ambidexters -75 až 75 43

lefthanded -75 až -100 54

(Knecht a spol., 2000) Functional transcranial Doppler sonography

SPEECH AND LATERALITY

Patient is fixing the pointIn the middle of the picture

SaysLAURA…

KnowsPETER...

Lefthemisphere

righthemisphere

Recognizesfeatures

Recognizeswhole picture

LEFT HEMISPHERE

Spoken and perceived speech is percieved as written without intonation

Disturbance of non-speech perception, does not recognize people according to his/her voice

Verbal memory(does not remember faces, remembers home address)

RIGHT HEMISPHERE

Distinguishes non-speech sounds (melodies, sound of the wind... recognises people according to his/her voice)

Disturbance of perceived and produced speech

Spatial memory (does not rememeber the address, but rememebers the way)

SPLIT BRAIN

COMMISSURAL FIBERS

CONNECTING THE

HEMISPHERES

200 million of fibers

Most of them inhibitory

CALLOSOTOMY

COMMISSUROTOMY

CORPUS CALLOSUM

MALES TEND TO EXHIBIT MORE

LATERALIZATION OF SPECIFIC TASKS

FEMALES USE BOTH HEMISPHERES

MORE SYMETRICALLY

WOMEN EXCELL IN VERBAL ABILITIES

MEN EXCELL IN SPATIAL ABILITIES

BRAIN LATERALITY

FUNCTIONAL DOMINANCE OF THE

HEMISPHERES

GENDER MAINSTREAMING

EQUAL CHANCES DOES NOT MEAN EQUAL ABILITIES

FEMININITY, MASCULINITY AND COGNITIVE FUNCTIONS