CS&D Exam 3

CN 7/Facial

origin: caudal pons, medulla
motor function: facial expression
sensory function: taste from anterior 2/3 of tongue, sensation from ear canal
decussation: complex

CN 8/Vestibulocochlear

origin: pontomedullary junction, thalamus, pons, midbrain
function: hearing and vestibular sense
decussation: complex

CN 9/Glossopharyngeal

origin: pons and medulla
motor function: swallowing
sensory function: sensation from, ear, ear canal, pharynx, and posterior 1/3 of tongue
decussation: complex

CN 10/Vagus

origin: medulla
motor function: swallowing, speech, voice
sensory function: sensation from pharynx, meninges, and ear canal, taste from epiglottis and pharynx
decussation: none

CN 11/Spinal Acessory

origin: upper cervical spinal cord
function: controls movement of head and neck, sternomastoid and upper trapezius
decussation: complex

CN 12/Hypoglossal

origin: medulla
function: intrinsic tongue muscles
decussation: medulla

Ataxia cerebellar lesions

ipsalateral to side of lesion

Midline vermis region lesions

cause unsteady gait and eye movement abnormalities, often accompanied by vertigo, nasuea, and vomiting

Lesions lateral to vermis

cause ataxia of limbs

Lateral cerebellar hemispheres

motor planning for extremities

Intermediate cerebellar hemispheres

distal limb coordination

Vermis

proximal limb and trunk coordination

Flocculonodular lobe

balance and vestibulo-ocular reflexes

Striatum

caudate and putamen

Structures of basal ganglia

caudate, putamen, globus pallidus, subthalamic nucleus, substantia nigra

Caudate nucleus

cognitive control of motor activity, learning, goal directed behavior

Putamen

regulates execution of learned and habitual motor movements

Globus pallidus

major output of nucleus, modulates motor commands via inhibitory control of thalamus

Subthalamic nucleus

excititatory input to globus pallidus, key in indirect pathway suppressing unwanted movements

Substantia nigra compacta

dopamine production and striatal modulation

Substantia nigra reticulata

output control to thalamus and brainstem

Nucleus accumbens

mood, reward, motivation, and reinforcement learning

Peripheral nerve lesions (LMN)

weakness, reducted tone, loss of reflexes

UMN lesions

rigid, increased reflexes

Motor lesions

paralysis, hypotonia, hyperreflexia

Association cortex lesions

apraxia

BG lesions

rigid, involuntary movements

Cerebellum lesions

hypotonia, ataxia

Outer and middle ear

convery airborne vibrations to inner ear

Basilar membrane

supports organ of corti, vibrating in response to travelling wave of cochlear fluid

Organ of corti

tonotopically organized

IHCs

sensory, conrolled by afferents

OHCs

amplifiers, controlled by efferents

Ascending auditory pathway

generates measures electrical signal

Middle ear muscles

contract in response to loud sounds

2 types of hearing loss

conductive or sensorinerual

4 aspects of sound controlled by auditory nerve

intensity, frequency, location, timing

Cochlea

converts mechanical signal into biological signal

Inner hair cells function

sensory transducers, convert sound into electrical signal

Outer hair cells function

amplify, compress, and refine basilar membrane tuning

Oval window

translates mechanical vibration of ossicular chain into a pressure wave

Round window

acts as a pressure relief

Conductive hearing loss

prevents sound from reaching labryinth

Sensorineural hearing loss

damage to hair cells, cochlear nerve fibers, or cochlear nuclei

Range of hearing (frequency)

20-20,000 Hz

Range of hearing (intensity)

0-130

Cochlear implants

directly stimulates auditory nerve, array of electrodes in cochlear canal stimules afferents

Peripheral nerves for voice

phrenic, intercostal, and subcostal

Muscles for voice

diaphragm, internal and external intercostals of rib cage, abdominal wall

Dorsal stream (voice)

auditory motor, determines how to reproduce heard sounds within our own vocal tracts

Ventral stream (voice)

auditory conceptual, linking memory to sound sequence

Inferior frontal gyrus effect on voice

syntatic and semantic language processing, reading, speech motor control

SMA effect on voice

initiation and sequencing of serial movements

ACC effect on voice

initiation and control of affective components of vocalization

Supramarginal gyrus effect on voice

comparing expected vs actual sensory feedback

4 factors influencing speech motor development

anatomical constraints, motor planning, motor and feeding habits, language growth

Primary voice function

protection of airway

Secondary voice function

communication

3 aspects of swallowing

safety, effiency, participation

CN X effect on voice

innervation of intrinsic laryngeal muscles, vocal fold movement

Cranial nerves involved in voice

5, 7, 9, 10, 11

CN V effect on swallowing

chewing, oral floor support, soft palate tension

CN 7 effect on swallowing

lip seal, cheek compression, hyoid positioning

CN 9 effect on swallowing

pharyngeal and laryngeal elevation

CN 10 effect on swallowing

palatal closure, pharyngeal propulsion, airway protection

CN 11 effect on swallowing

tongue shaping, bolus control and propulsion

Higher brain networks and swallowing

initiate swallowing and refine response

Medullary swallowing networks

organize timing and sequence of muscle activity

Dysphagia

difficulty swallowing, important for saftey and quality of life

2 Conditions that can result in dysphasia

ALS, stroke

Main components of the limbic system

hippocampus, amygdala, hypothalamus, thalamus

Olafactory receptor neurons

send unmyelinated axons in olafactory nerves throuogh cribiform plate to reach olafactory bulb

Cells ORNs synapse onto

mitral and tufted cells

Working memory

holding a particular concept briefly in awareness while a mental operation is performed

Declarative long term memory

memories of facts, data, and personal events you can consciously retrieve and describe

Non declarative long term memory

unconscious memories and capacities that guide behavior without requiring active thought

Long term storage of declarative memory

neocortex

Long term storage of non declarative memory

basal ganglia and cerebellum

Learning and retrieval of declarative memory

hippocampus, medial temporal lobe, and medial diencephalon

Working memory brain area

prefrontal cortex

Amygdala

autonomic functions, involuntary movements, pleasure, and reward

Higher order functions

functions of heteromodal association cortex, more than basic primary sensory or motor functions

Functional localization

map specific processes to distinct brain regions

Left hemisphere dominant

fast temporal processing, details, verbal ability

Right hemisphere dominant

spectral processing, music ability, emotion recognition

Medial temporal lesion

declarative learning

Sub cortical lesion

non declarative learning

Frontal lobe lesion

executive function

Thalamus lesion

sustained attention

Executive function

cognitive functions that are responsible for goal directed, non routine behavior

Frontal and temporal lobe localization

learning new information

PFC localization

shifting selective attention

Limbic and heteromodal assocation cortex localization

decision making

Factors negatively influencing executive function

developmental disorders, lesion, daily factors

Developmental trajectory

perceptual and motor measures peak in early 20s, verbal classification peaks in 40s, verbal retrieval peaks in 50s-60s

Developmental acquired disorders with executive function deficits

aphasia, neurogenic communication disorders, frontotemporal dementia

6 principles of neuroplasticity

1) experience changes the brain at any age
2) nature of experience influences nature of change
3) timing is everything
4) neurogenesis is a possible change
5) plastic changes require repetition and maintenance
6) recovered brain is sensitive to drugs and other effects