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

BRAIN LESION IN PATIENT WITH

BROCA´S AFASIA

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...

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

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 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

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)

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

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

LEFT HEMISPHERE RIGHT HEMISPHERE

LEFT HEMISPHERE

SYSTEMIC

SYSTEMIZING

RIGHT HEMISPHERE

EMOTIONAL

EMPHATIZING

GENDER DIFFERENCES IN BRAIN LATERALITY AND FUNCTIONAL SPECIALIZATION OF BRAIN HEMISPHERES