Transcript Nervous System: Speech

Nervous System:
Speech & Language
Chapter 11
Perry C. Hanavan, Au.D.
The nervous system is important
for moment and speech
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Movement
respiration
phonation
articulation
all aspects of:
– speech production
– speech perception
The nervous system divisions
• CNS
– brain and spinal cord
– glial cells
• astrocytes
– oligodendrocytes
• forms myelin
• PNS
– cranial nerves and
spinal nerves
– Schwann cells
• forms myelin
There are various ways of organizing
the function and anatomy
CNS
Cerebrum
(cortex, basal nuclei, thalamus,
hypothalamus)
(parietal, temporal, frontal, occipital
limbic lobes)
Midbrain
Brainstem
Cranial
(pons, medulla)
Nerves
Cerebellum
Spinal Cord
Spinal
Nerves
PNS
Somatic
Autonomic
Afferent
Efferent
Sympathetic
Parasympathetic
CNS
Functional divisions
Somatic nervous system: voluntary, controls skeletal muscle
Autonomic nervous system: involuntary, controls smooth muscle
The neuron is the basic unit of the
nervous system
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dendrites
cell body
axon
terminal boutons
synapse
myelin
nodes of Ranvier
neurotransmitters
Synapse
There are various classifications of
neurons.
• Number of Processes
– unipolar
– bipolar—spiral ganglion of auditory nerve
– multipolar
• Golgi Type I—innervate muscles or glands--myelinated
• Golgi Type II—innervate nearby neurons in cns--unmyelinated
• Function
– Afferent—towards cns from sensor
– Efferent—towards muscle or gland from CNS
– Interneurons—between neurons
• Neurotransmitters
– Dopaminergic--dopamine
– Cholinergic--acetylcholine
– Serotonergic--serotonin
Question
Afferent is?
A. From CNS
B. Towards CNS
C. Between interneurons
D. All the above
E. None of the aboe
Question
Spiral ganglion is?
A. Unipolar
B. Bipolar
C. Tripolar
D. Quadrapolar
E. Multipolar
There are various types of sensory
receptors involved in speech
Teleceptors
Exteroceptors
Proprioceptors
distance
near
position in space
Visceroceptors
Mechanoreceptors
Thermoceptors
Nocioreceptors
Photoreceptors
Chemoreceptors
Baroreceptors
viscera
pressure
temperature
tissue damage
light
taste, smell
air pressure
eyes, cochlea
skin
semicircular canals
muscles, tendons, joints
visceral structures
tissue
tissue
retina
tongue, nose
trachea, bronchi
Question
Proprioceptors sense?
A. Air pressure
B. Distance
C. Pressure (touch)
D. Position in space
E. Temperature
CNS
Fissures
Cerebralspinal fluid serves a
number of functions
• Meninges—surrounds brain and
spinal cord
• Ventricles—four csf filled cavities
filled within brain
• Cerebral spinal fluid produced by
choroid plexis cells in ventricles
– composed of proteins and glucose,
lymphocytes
– circulates throughout meninges and
ventricles
– protects from trauma—shock
absorbing
– provides buoyancy in fluid to lighten
weight of brain
Cortex is the outer grey matter
located in the cerebrum of the brain
• Unmyelinated primary
sensory, motor, association
and limbic areas
• Irregular shaped portion
consisting convolutions
– gyri—raised surfaces
– sulci—shallow depressions
– fissure—deep depressions
• longitudinal—divides
hemispheres
• lateral—superior, inferior
division
• central sulcus—anterior,
posterior
Matter
grey matter
white matter
Question
Which lobe of the brain is primarily involved
in speech production?
A. Temporal
B. Frontal
C. Parietal
D. Occipital
E. Limbic
The lobes of the brain have
important functions
• frontal—reasoning, problem solving, personality,
speech and language production
– motor strip
– Broca’s area—speech production
• parietal—somatosensory (touch, pain,
proprioception, temperatures)
– sensory strip
– angular gyrus
– supramarginal gyrus
• temporal—understanding
– auditory cortex
– Wernicke’s area
• occipital—reception and processing of visual
information
• limbic—hippocampus, amygdala, and medial
margins of the temporal, parietal, and frontal
lobes that function for emotions, sexual function,
temperature regulation and feeding behavior
Lobes, Brodmann’s Areas
Selected Brodmann’s Areas
Speech Language Areas
Speech/Language Areas
Supplementary Motor Area:
Motor, sensory, word generation, and working
memory.
Speech/Language Areas
Supramarginal Gyrus
Thought to contribute to written language and
possible phonological storage as well as visual
word recognition.
Speech/Language Areas
Angular Gyrus
(1) Association areas and allows cross
modal transfer and associations between
either vision or touch and hearing (2). As
the angular gyrus is important in the
processing of associating a heard name to a
seen or felt object, it is probably also
important for associations in the reverse
direction. A "name" passes through
Wernicke's area, then via the angular gyrus
arouses associations in the other parts of
the brain (2). Thus, the angular gyrus acts
as a way station between the primary
sensory modalities and the speech area.(2).
The development of language is probably
heavily dependent on this area. Object
naming, one of the simplest aspects of
language, depends on associations
Lobes of the brain
Cerebral Cortex
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Frontal Lobe- associated with reasoning, planning, parts of speech, movement,
emotions, and problem solving
Parietal Lobe- associated with movement, orientation, recognition, perception of
stimuli
Occipital Lobe- associated with visual processing
Temporal Lobe- associated with perception and recognition of auditory stimuli,
memory, and speech
Question
The sensory strip is located in the?
A. Frontal lobe
B. Temporal lobe
C. Occipital lobe
D. Parietal lobe
E. Limbic lobe
Motor and Sensory Cortex
Motor Strip
Motor Cortex
Motor Cortex
Motor Cortex
Cortical connections play a
fundamental role in the brain
• commisures—links the
two hemispheres of
brain (right and left)
– corpus callosum
• association fibers—link
cerebral areas of brain in
same hemisphere
– arcuate fasciculi
• projection fibers—links
grey matter with other
regions of the brain
– internal capsule
Projection Fibers (white
matter sheets)
Interconnections
Neuro-speech-language
Subcortical areas of the brain play
a primary role in motor function
• basal ganglia/nuclei
– caudate nucleus,
putamen and
globus pallidus.
Ventricles of the Brain
• Ventricles
Basal Nuclei
• Control voluntary movements and
establishing postures. When they
are altered - as in disorders
Huntington or Wilson disease unwanted movements, such as
involuntary jerking movements of
an arm or leg or spasmodic
movement of facial muscles.
• The caudate nucleus, putamen and
anterior limb of the internal capsule
are collectively known as the
corpus striatum (i.e. striated
body) based on appearance.
• Similarly, the shape of the putamen
and globus pallidus resembles a
lens, and collectively called the
lenticular nucleus.
The thalamus processes and
transmits to and from cortical areas
• A large mass of gray matter
deeply situated in the forebrain.
There is one on either side of the
midline.
• Relays to the cerebral cortex
information received from
diverse brain regions--a requisite
'last pit stop' for information
going to cortex.
• Axons from every sensory
system (except olfaction)
synapse here as the last relay
site before the information
reaches the cerebral cortex.
• There are other thalamic nuclei
that receive input from
cerebellar-, basal ganglia- and
limbic-related brain regions.
Limbic System
• Limbic System
Midbrain
• A rostral part of the brainstem if
impaired in its core (i.e. the
tegmentum), results in loss of
consciousness or coma, because it
contains the rostral end of the reticular
formation.
• The dorsal or posterior part has the
superior colliculus is important for
visual system reflexes, and the inferior
colliculus is important for auditory
system function.
• The ventral or anterior part has the
cerebral peduncle, which is a huge
bundle of axons traveling from the
cerebral cortex into/ through the
brainstem; those fibers are important for
voluntary motor function.
• Two other structures in the depth of the
midbrain that are important for normal
motor function are the red nucleus (not
visible) and the substantia nigra.
Brainstem
Anatomy:
• Midbrain
• Pons
• Medulla
Function:
• Alertness
• Arousal
• Breathing
• Blood Pressure
• Most of the Cranial Nerves
• Digestion
• Heart Rate
• Other Autonomic Functions
• Relays information between the Peripheral Nerves and
Spinal Cord to the Upper Parts of the Brain
Brainstem
Cranial Nerves
Peripheral Nerves
Spinal Cord
Spinal Cord
Spinal Cord: Region and Areas
Spinal Nerves: Afferent &
Efferent
Cranial Nerves
• CN V – Trigeminal
– Sensory
• Touch, pressure, pain,
proprioception, and
temperature from various areas
of the face
– Upper lip, teeth, upper oral
cavity, lower lip and teeth,
lower jaw and oral cavity
– Motor
• Muscles of mastication and
some extrinsic laryngeal
muscles
• Tensor veli palatini muscle
• Tensor tympani muscle
Trigeminal Nerve: V
Cranial Nerves
CN VII Facial
• Motor
– Muscles of facial expression;
extrinsic laryngeal muscles, and
stapedius.
– Parasympathetic innervation of the
lacrimal, submandibular, and
sublingual glands (salivary glands),
as well as mucous membranes of
nasopharynx, hard and soft palate.
• Sensory
– Taste sensation from anterior 2/3 of
tongue; hard and soft palates.
– General sensation from the skin of
the concha of the external ear and
from a small area behind the ear.
Facial Nerve: VII
Cranial Nerves
• CN VIII Auditory/Vestibular
– Vestibular
• Balance—rotary and linear
– Auditory
• Sound
Cranial Nerves
• CN IX Glossopharyngeal
– Sensory
• Taste from the posterior onethird of the tongue
• Sensations of pain, touch,
and temperature from
external ear, Eustachian
tube, tonsils, pharynx, and
pharynx
– Motor
• Involved in swallowing
(pharyngeal muscles)
• Salivary glands
Glossopharyngeal: IX
Cranial Nerves
• CN X - Vagus
– Motor
• Soft palate, pharynx, and larynx
– Phonation (pharyngeal, superior
laryngeal and recurrent laryngeal
nerves)
• Heart, thoracic, and abdominal
smooth muscles, glands
– Sensory
• Thoracic and abdominal viscera,
larynx, pharynx, trachea, esophagus
• Taste buds around epiglottis
• External ear canal
Vagus Nerve: X
Cranial Nerves
• CN XII – Hypoglossal
– Motor
• Intrinsic and extrinsic
muscles of tongue,
extrinsic laryngeal
muscles
– Sensory
• The pharyngeal phase
of swallowing is
monitored by
hypoglossal nerve
Hypoglossal Nerve: XII
Language Zone
Corticospinal Motor Path
Corticonuclear Motor Path
Vascular
Major Vascular System
Blood Supply: Brain
MRI & CT Scan
Stroke
Speech Language Areas
Speech/Language Areas
Supplementary Motor Area:
Motor, sensory, word generation, and working
memory.
Speech/Language Areas
Supramarginal Gyrus
Thought to contribute to written language and
possible phonological storage as well as visual word
recognition.
Speech/Language Areas
Angular Gyrus
(1) Association areas and allows cross modal
transfer and associations between either vision
or touch and hearing (2). As the angular gyrus
is important in the processing of associating a
heard name to a seen or felt object, it is
probably also important for associations in the
reverse direction. A "name" passes through
Wernicke's area, then via the angular gyrus
arouses associations in the other parts of the
brain (2). Thus, the angular gyrus acts as a way
station between the primary sensory modalities
and the speech area.(2).
The development of language is probably
heavily dependent on this area. Object naming,
one of the simplest aspects of language,
depends on associations between other
modalities and audition