Neurogenomics of Speech and Language Disorders
,Lesson 1
Vocalization mechanisms:
Air exhaled from lungs drive oscillations of vocal ‘cords’ in the larynx. The
rate of oscillation determines the pitch.
Acoustic energy passes through the vocal tract (pharyngeal, oral & nasal
cavities) and out to environment via nostrils/lips.
Filtering: formants modify sound, only some frequencies get through.
Formants are determined by the length/shape of the vocal tract; they are
modified by moving articulators (tongue, lips, soft palate...).
So for example ‘beet’, ‘boot’, ‘bought’ & ‘bat’ differ in formant structure.
The importance of motor control in speech
Fine rapid movements of vocal articulators (tongue, lips, jaw etc.) closely
synchronised with each other and with vibrations of larynx, e.g. ‘pat’ versus
‘bat’, depends on when larynx begins vibrating relative to vocal tract
movements. Tiny difference in timing can change phonemes.
Decoding neural basis of language
The Broca’s area and Wernicke’s area are important for speech and language. With structural MRI
you can analyse in vivo scans instead of waiting for people with lesions in brain areas to die and do
post-mortem studies.
Some species are better in vocal learning than others. Exp. Hummingbirds, bats, humans, parrots.
, There are differences in the larynx, the larynx in humans are lower than in apes. This could be the
reason that we can produce speech, because the tongue can really move backwards and forwards.
The lowering of the larynx was thus an important step in evolution of speech.
Humans also communicate with sign language. Non-verbal communication.
Speech and language disorders
You can do Twin studies to study speech and language disorders. For instance comparing identical
twins to unidentical twins.
Question: one of the twins has a language disorder, does the other twin also have a language
disorder?
If the concordance is more prevalent in identical twins than in unidentical twins you can say that it
has something to do with genetics.
,Lesson 1
Vocalization mechanisms:
Air exhaled from lungs drive oscillations of vocal ‘cords’ in the larynx. The
rate of oscillation determines the pitch.
Acoustic energy passes through the vocal tract (pharyngeal, oral & nasal
cavities) and out to environment via nostrils/lips.
Filtering: formants modify sound, only some frequencies get through.
Formants are determined by the length/shape of the vocal tract; they are
modified by moving articulators (tongue, lips, soft palate...).
So for example ‘beet’, ‘boot’, ‘bought’ & ‘bat’ differ in formant structure.
The importance of motor control in speech
Fine rapid movements of vocal articulators (tongue, lips, jaw etc.) closely
synchronised with each other and with vibrations of larynx, e.g. ‘pat’ versus
‘bat’, depends on when larynx begins vibrating relative to vocal tract
movements. Tiny difference in timing can change phonemes.
Decoding neural basis of language
The Broca’s area and Wernicke’s area are important for speech and language. With structural MRI
you can analyse in vivo scans instead of waiting for people with lesions in brain areas to die and do
post-mortem studies.
Some species are better in vocal learning than others. Exp. Hummingbirds, bats, humans, parrots.
, There are differences in the larynx, the larynx in humans are lower than in apes. This could be the
reason that we can produce speech, because the tongue can really move backwards and forwards.
The lowering of the larynx was thus an important step in evolution of speech.
Humans also communicate with sign language. Non-verbal communication.
Speech and language disorders
You can do Twin studies to study speech and language disorders. For instance comparing identical
twins to unidentical twins.
Question: one of the twins has a language disorder, does the other twin also have a language
disorder?
If the concordance is more prevalent in identical twins than in unidentical twins you can say that it
has something to do with genetics.
