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