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LANGUAGE and the BRAIN
by Dr. ALEC GILL MBE
PSYCHOBIOLOGICAL SCHOOL OF PSYCHOLOGY
GESCHWIND
(1970s) - Left
Hemisphere research on Language:
- APHASIA (Medical Dictionary) the loss of ability to understand or express speech owing to brain
damage. Most of the early findings came from work on soldiers with bullet wounds to the
head (c1860s Franco-Prussian War); stroke victims; electrical stimulation; psycho-surgery; and drugs.
- Paul BROCA (1861
French) described 'BROCA'S AREA' near the motor cortex which controls the
muscles of the face (jaw, tongue, larynx, etc.) involved with the physical production of
speech. This area, like the others, is often found in the left hemisphere. In BROCA'S APHASIA speech is slow and laboured. Articulation is crude. Speech is
telegraphic with sentences clipped and patients find it difficult to use words such as No,
If, And or But.
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Carl WERNICKE (1874 German) gave his name to a region of the brain near where auditory
stimuli are received. Damage to this area produces speech which is fluent, but has little
content. Speech can be very rapid, but the patient fails to use the correct word and
substitutes for it a long (circumlocutionary) phrase - e.g., "What you use to cut
bread with" for 'Knife'. And say lots of EMPTY words such as "thing" -
'pass that thing'. Even though hearing is fine for music and sounds, damage in Wernicke's
area can produce a severe loss of understanding words.
- ARCUATE FASCICULUS is also found mainly in the left hemisphere. It connects the above
two areas. If this alone is damaged, a patient's speech is fluent but abnormal, and words
can be understood but not repeated. So they know what is said, but cannot reply in
the normal way.
- THE ANGULAR GYRUS in some unknown way converts visual information into the
appropriate auditory form from the Visual Cortex (Occipital Region) - when reading words
and turning them into speech. The three simple letters "C-A-T" are read as
'Cat' [this simple process is a minor miracle in itself].
- PRIMITIVE / DEEP BRAIN tends to retain swear words which express emotions. Equally,
some patients can sing simple songs with no problems (perhaps learned in childhood and
stored in the primitive part of the brain) - more research needed.
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