nuero 4245 Exam 3 vocab

Optic nerve

goes from retina to optic chiasm

optic tract

goes from chiasm to LGB

Optic radiation fibers

goes from LGB to visual cortex

visual field

what you can see

retinal field

reverse of visual (Left= right)

Aqueous humor

the clear fluid filling the space in the front of the eyeball between the lens and the cornea, similar to CSF, produced by Choroid plexus, too much is glaucoma

retina

photoreceptors, bipolar cells, ganglion cells, convert light into action potentials

fovea

center of retina, color vision best bc of high concentration of coens

cones

30 million, foveal retina, need bright light, color vision, high visual acuity

rods

100 million, extra foveal retina, lower light, night vision, low visual acuity

blindspot in eye

point where the optic nerve converge to exit eye and into the brain (OPTIC DISK) no light sensitive cells to detect light rays

Visual dorsal stream

dorsal bundle goes straight to cells in the cortex carrying info about the upper retinal quadrants (lower visual field)

visual ventral stream

ventral bundle forms meyers loop and enters the visual cortex below the calcarine fissure with lower retinal quadrant

what is the role of the frontal lobe in aiding object identification

helps to categorize and classify objects and distinguish from one another

what happens with a lesion in the primary visual cortex?

blindness in opposite field of cision/blindsight

what happens with lesion in visual association cortex?

visual agnosia (cant recognize object, visual apraxia (deficits in visuo spatial tasks), prosopagnosia, deficits in facial recognition, alexia with/out agraphia (cant comprehend written language but can write)

how many hemispheres in the cerebellum?

2

how many lobes in the cerebellum?

3 (anterior, posterior, flocculonodular)

how many nuclei in cerebellum?

4 (dentate, emboli form , globose, fastigal)

what are the longitudinal zones of cerebellum?

median, paramedian, lateral

Function of flocculonodular lobe

balance, equilibrium of eye movements

function of anterior lobe

ipsilateral muscle tone, walking posture

function of posterior lobe

coordinated cortically initiated skilled movements
updates basal ganglia and cortex for adjustment
contralateral

Function of fastigial nucleus

adjusts body posture/balance

function of emobolifrom and globose nuclei

regulates ipsilateral arm/leg movement

function of dentate nuclei

works with BG to produce coordinated ipsilateral limb movement

function of median division

posture

function of maramedian divsion

regulates movement of ipsilateral extremities

function of lateral division

regulates more skilled movements of ipsilateral extremities

function of inferior peduncle

afferent fibers, ipsilateral, used to maintain upright posture and balance during movement

function of middle peduncle

afferent contralateral motor cortex combines with visual and auditory info guides ongoing movement relative to environment

function of superior peduncle

ongoing movement

ataxia

poor muscle control, uncoordinated muscle activity

dysdiodokinesia

inability to perform rapid movements

Dysarthria

slurred and impaired speech due to poor speech muscle control

Dysmetria

over or undershooting, error in judgement

intention tremor

task specific tremor in motion

hypotonia

decreased muscle tone, floppy

disequilibrium

loss of equilibrium or stability

ataxic dysarthria

impaired motor speech, usually following bilateral cerebellar lesions

rebounding

impaired muscle tone adjustment

what are the structures of the Basal Ganglia

caudate nucleus, putamen, globus pallidus

what structures make up the striatum

caudate nucleus and putamen

function of Basal Ganglia

refine cortically initiated motor activity, adjust automatic movements, motor learning

what structures are not in the BG but are closely connected

subthalamic nucleus, substantia nigra

function of putamen

regulate movement and influence various types of learning

function of globus pallidus

OUTPUT
-huge in motor control

function of caudate nucleus

responsible for voluntary movement

cognitive functions of BG

attention, working memory, cognitive flexibility, initiative and drive and emotion

Direct BG pathway

important for making movements
makes it more active
the thought is the stimulus
sends excitatory and synapses with inhibitory in the globus pallidus

what is the difference between inhibitory and excitatory neuron

inhibit- GABA
excite- glutamate

if you excite an inhibitory neuron, is is more inhibited or more excited

more excited

Does the addition of the impulses from the substantia nigra make more movements or less?

Dopamine from the substantia nigra excites the inhibitory pathway making more inhibition in the globus pallidus and therefore thalamus is more active= more movements.

what does the indirect pathway do

makes less active

When the subthalamic nucleus gets excited, it sends excitatory messages to which nuclei?

globus pallidus internal

when we excite neuron talking to the thalamus, what happens to motor movements

thalamus is less active and less motor movement

dystonia spasmodic

altered posture

Sydenham's chorea

movement disorder resulting from bacterial infection

huntingtons chorea

an inherited neurological disease characterized by rapid, jerky, involuntary movements and increasing dementia due to the effects of the basal ganglia on the neurons

Hemiballismus

rare decreased activity in subthalamic nuclei results in flailing and choreic movements

Athestosis

slow involuntary movements

Parkinson's disease

loss of dopamine in substantia nigra increase in excitatory drive in basal ganglia

what are the motor related structures in frontal lobes

primary motor cortex
premotor cortex- voluntary muscle movement planning/coordination of movement
frontal eye field- voluntary rapid eye movements

functions of primary motor cortex

execution of precise, discrete, skilled, motor actions via descending motor pathway. controls groups of muscles

UMNs vs LMNs

UMNs- cortical motor neurons and axons BEFORE they synapse on spinal motor neurons
LMS- motor neurons located in brainstem and spinal cord that directly project to muscles

UMN syndrome

contralateral symptoms, immediate onset lasting days, positive Babinski, hypo/hyper reflexiva

LMN Syndrome

ipsilateral symptoms, acute and permanent, atrophy becomes severe, involuntary extraneous movements

ALS

amyotrophic lateral sclerosis- affects upper and lower motor neurons, starts with weakening of bulbar muscles, gene mutation, chemical imbalance

hemiplegia

spastic, in UMN, unilateral fixed extremity and neck, alternating unilateral lesion in brainstem causes different lateralization of CN vs Spinal LMNs

Pseduobulbar Palsy

bilateral corticobulbar, lesion above ponto medullary level, spastic paralysis of muscles of face, mouth, layrnx

Tactile Sensation of tongue

CN-V: anterior 2/3 of tongue
CN IX- Posterior 1/3 of tongue

taste sensation of tongue

CN VII- Anterior ⅔ of tongue
CN-IX Posterior ⅓ of tongue

Sensory innervation of velum and pharynx

CN-IX, CN X

Motor innervation of velum and pharynx

Cn V, CN IX and CN X

What would you expect from bilateral cranial nerve XII damage?

flaccid dysarthria

what are the 6 cranial nerves involved in speech and swallowing?

Trigeminal, facial, glossopharyngeal, vagus, spinal accessory, hypoglossal

CN I

Olfactory, sensory, smell, connects to amygdala and hippocampus

CNII

Optic, Sensory, visual info to gaze control in brainstem, from retinal to lateral geniculate body to occipital lobe

CN III

oculoMOTOR, upward and medial eye movement, raising upper eyelid, pupillary constriction
works with CN IV AND CN VI

CN IV

trochlear, motor,

CN V Trigeminal nerve

both - sensation of epicritic and protopathic, motor for mastication, chewing swallowing

CN VI

Abducens, motor, moves eye laterally,

CN VII

FACIAL- BOTH- movement of muscles, face, scalp, stapedius, sesnory taste in anterior 2/3 of tongue, bilateral cortical innervation to upper face

CN VIII

Vestibulocochlear- sensory, hearing and balance,

CN IX

Glossopharyngeal. Both sensory and motorSensory-taste on the posterior part of the tongue. Motor - Cough

CN X

Vagus nerve, both, tactile sensation from larynx, pharynx, abdomen, sensation of taste, controls velum for swallowing and phonation,

CN XI

Spinal Accessory- motor, head movement

CN XII

Hypoglossal (motor), controls all tongue movement, works with CN V, IX, X, to mediate chewing and swallowing

corticobulbar tract

Control all voluntary muscles of speech (except respiratory)
synapses in brainstem after decussation, 70% of descending fibers
unilateral lesion does not profoundly impair functions of CNs
2 neuron pathway

corticospinal tract

2 neuron pathway, synapses in spinal cord
Most fibers decussate to contralateral caudal medulla forming lateral corticospinal tract
Some descend ipsilaterally forming anterior corticospinal tract and decussate in the cord & synapse w/ LMN
Note: synapse after decussation

which sensory branches are in the trigeminal nerve?

Opthalmic, Maxillary, mandibular

what happens with damage to trigeminal nerve?

ipsilateral loss of sensation, loss of sneeze and blink reflex, sudden repetive bursts of pain usually in opthalmic or mandibular branch of CNV

damage to pons implications on facial nerve

Paralysis of ipsilateral facial muscles, excessive secretion from glands, loss of taste from anterior 2/3 of tongue

which cranial nerves mediate chewing and swallowing?

glossopharyngeal, vagus, hypoglossal

bilateral medullary damage to vagus nerve?

lethal bc it participates in swallowing, coughing breathing and cardiac rate

unilateral damage to vagus nerve

swallowing problems, paryalysis or paresis of soft palate, pharynx, larynx, voice problems due to unilateral paralysis of vocal folds

does the primary motor cortex control individual or groups of muscles

groups

if someone has a stroke that damages left inferior frontal gyrus, what disorders might they have based on damage to near by tissue

44,55 ,6,4
Speech, weakness, complete paralysis, apraxia of speech
6- planning and programming of movements- so you could have discoordination
MCA- artery of aphasia

unconscious proprioception of cerebellum

2 neuron organization, 3 fiber tracts
necessary for skilled movement

lesions affecting anterior lobe of cerebellum cause

cerebellar motor syndromes