what allows the ability to self-modulate pain response through production of serotonin, endorphin, etc
Periaqueductal gray in the ventricular system
where is the primary auditory cortex located?
Located in transverse temporal gyri of Heschl
part of temporal lobe
what would the light reflex eye exam look like for unilateral L optic nerve lesion aka Optic Neuritis of L Eye
- Direct light into L eye–> no direct response or consensual from right
- direct light into R eye–> get direct and consensual from the left
what CN make up the corticobulbar tracts that innervate the head and neck
(projections to brainstem)
CN 3, 4, 5, 6, 7, 11, 12
what is ageusia
inability to taste
- guided by external stimuli
- (eg., postural control muscles are activated even before reaching for an object)
premotor area of frontal lobe
how do you consider what hemisphere is dominant
Dominant hemisphere is the one which is more important for language comprehension and production (usually L)
- Semidetached mass of neural tissue anchored to the posterior brainstem
- Involved in sensory processing, postural control and coordination of voluntary movements
cerebellum
otoliths of utricles get displaced into semicircular canals
-caused by head trauma, aging, viral, positional
benign positional vertigo
what CN are associated w/ the medulla
CN 9, 10, 11, 12
- information for lower head and neck
neglect to left side is due to
lesion on right parietal lobe
**lesion on right is more common
- Role in planning, learning complex internally generated movement
- Engaged when thinking about activity (i.e. learning to walk again)
SMA of frontal lobe
Projections to hypothalamic centers (in thermoregulation) mediates what?
controls body temperature and maintain constant core body temperature
examples of what type of motor neuron disease/injury?
Polio
Spinal muscular atrophies
LMN
- Respond to muscle load (how contracted a muscle is)
- Excited when contract own muscle
- Reside in tendons or musculotendinous junction
GTOs
non motor complications associated w/ parkinsons
- Cognitive decline
- Daytime sleepiness
- Pain
- Urinary incontinence
- Hallucinations
- Motivational apathy
- Postural hypotension
- Fatigue
what is the fxn of the reticular formation?
integrates fxn of respiration, consciousness and complex motor patterns
Every input (i.e. sense) that is used by conscious awareness makes connection in \_\_\_\_\_→ every movement has to have permission from \_\_\_\_ -Exception: \_\_\_
Thalamus
Exception: Olfaction stops at cortex first then goes to Thalamus
what does the pre-frontal cortex have connections to?
thalamus, hypothalamus and limbic system, reticular formation
(Whatever is happening in limbic system, reticular formation, etc. can affect what is happening in prefrontal cortex)
w/ weber test, hear tone louder in affected ear
unilateral conduction deafness
what is the functional role of the ventricles?
- Contains cerebrospinal fluid (CSF) which
1. Regulates composition of fluid bathing neurons and glial cells
2. Route for certain chemical messengers
signs of LMN disease
- decreased strength, muscle tone*, and stretch reflexes
- SEVERE atrophy
- fasciculations and fibrillations
roles in planning movement, programming complex movements (i.e. reach and grasp)
Pre-motor/SMA (supplementary motor area)
what is Hemianopia
loss of contralateral field from both eyes
can only see left or right side
what are signs of peripheral neuropathy
loss of pain, temp, touch sensations usually in LE
*don’t have flexor withdrawl reflex
what is a negative or positive sign
- negative: loss of fxn (smell, memory, speech)
- positive: appearance of behaviors not previously seen (clonus, tremor, tourrettes, hallucinations, bad smells)
presents with:
- contralateral paresis (followed by spasticity)
- decreased DTR
- positive babinski sign
lesion in the motor cortex
*UMN sign
Projections to somatosensory cortex (in thermoregulation) mediates what?
conscious appreciation of skin temperature and provide information to make behavioral adjustments to skin temperature (i.e. shivering)
where is the termination point of the DCML
Postcentral gyrus of the Parietal lobe
how do you evaluate an optic nerve defect?
- If CN III intact, the eye can still participate in consensual light reflex
- Right optic nerve is damaged, shine light in right eye→ no direct or consensual response
- Shine light in left eye→ direct and consensual response
- Often implicated in MS as CN I and II are part of CNS
- Wrap around muscle fibers and respond to change in length of muscle
- Rate dependent→ respond to speed in changes of the length
Muscle spindles
Describe where the CBs of 1st, 2nd, and 3rd order neurons are in the spinothalamic tract
1st- DRG (enter dorsal horn)
2nd- substantia gelatinosa
3rd- ventral posterior lateral nucleus of the thalamus
what receptor types of spinothalamic tract?
Nociceptor and Thermo-receptor
*Free nerve endings responding to mechanical, temperature, and chemical stimuli
describe the: -verbal output/fluency -repetition -comprehension in brocas aphasia
- Verbal fluency/output: decreased*
- Repetition: impaired
- Comprehension: intact*
*higher rates of depression–> knows what they want to say, cannot formulate the words
primary motor cortex are bunched together neurons and they make up the ___
cerebral peduncle
examples of what type of motor neuron disease/injury?
CVA
UMN
examples of gray matter in the cerebrum (4)
- cerebral cortex
- basal ganglia
- thalamus
- periaqueductal gray
lesions in broca’s area results in what?
- EXPRESSIVE APHASIA- loss of production of language→ can understand what you are saying and know what they want to say, but they cannot generate word
- syntax may remain intact
Spontaneous contractions of individual muscle fibers, not grossly visible but apparent in electrical recordings
fibrillation
*seen in LMN disease
where is the reticular formation?
in the brainstem
how is parkinson’s diagnosed?
medical hx, neurological exam, responsiveness to dopamine therapy
describe the: -verbal output/fluency -repetition -comprehension in Wernicke's area
- Verbal output/fluency: fluent/intact*
- Repetition: impaired
- Comprehension: impaired*
sx: neologism, jargon, paraphrasias
innervate muscle spindle receptors (read length and change in length in muscles)
gamma motor neurons (in anterior horn)
right hemisphere usually controls what?
spatial perception, music, drawing, left visual field
what is Wernickes aphasia
can say words but they don’t make sense
damage to hair cells or to cochlear nerve
ex. drugs, toxins, infections, neuroma
nerve deafeness
what tract transfers information (modality) about pain and temperature
spinothalamic tract
Presents w
- Loss of spontaneity in interacting
- Changes in personality, social behavior, mood- prefrontal cortex
- Difficulty problem solving
- Inability to express language
- Socially inappropriate behavior-may be sexual or aggressive in nature
frontal lobe pathology
what are the subcortical structures
Subthalamus, Thalamus, Diencephalon, epithalamus, hypothalamus
damage to CN 3 (oculomotor) results in waht
- lateral strabismus
- diplopia
*medial rectus paralyzed
what area of the frontal lobe controls executive function?
pre-frontal
(i.e. can I use different language based on what group I am with?)
*Integrates judgment, behavior, imagination, and emotion
(Personality and identity)
describe brown-sequard syndrome
-loss of pain and temp on contralateral side of the hemisection lesion and loss of fine touch on other
what attaches the cerebellum to the brainstem?
cerebellar peduncles (inferior, middle and superior)
Presents with:
- impaired stereognosis, two-point discrimination, and postural sense
- Tactile inattention-extinction
- Disorders in body image, spatial disorientation, visual agnosia
cortical lesion of parietal lobe
paired group of subcortical nuclei involved with movement and more (i.e. cognition and emotion); around each lobe of the thalamus
basal ganglia
describe the 2 major outputs of the reticular formation
- Ascending reticular activation system (ARAS) to determine level of consciousness
- DRAS to send projections down spinal cord and influence muscle tone, pain modulation, generate motor patterns (i.e. chewing, breathing, walking, etc.)
Lower visual field–>
Superior hemiretina
cell bodies in a big group (gray matter)
- nucleus
- ganglion
- body
generally describe the auditory pathways
- pathways are BILATERAL (become at medulla)
- high pitch/freq.= short sound waves= near oval window (*Lose as we age)
- low pitch/freq= larger waves = deeper in choclea
where is broca’s area
damage to this area results in brocas aphasia
posterior part of the left inferior frontal gyrus
what is prosopagnosia
cannot recognize faces
network of interneurons within the brainstem and SC that can act as pattern generators for rhythmic movements such as walking, chewing breathing
*modifiable by afferent and supraspinal inputs
central pattern generators
a paired structure that forms a major component of the vertebrate midbrain and has connections to visual system
superior colliculi
in right handed people, are the percentages of hemisphere dominance?
- 96% L
- 4% R
- 0% equally dominant
what tract transfers information (modality) about touch, presssure, proprioception, and vibration
Dorsal Column Medial Lemniscal System (DCML)
what re mammillary bodies sensitive to?
Vitamin B and thiamine levels
How many spinal cord segments are there in each section
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
why does the lumbar and cervical cord have larger gray matter?
bc there are larger nuclei associated w/ sacral and brachial plexus
what is broca’s aphasia
inability to express language due to frontal lobe pathology (left side)
what CN are associated w/ the midbrain
CN 3, 4
-higher face
loss of pain and temp on one side and loss of fine touch on the other indicates injury to what SC tracts?
- DCML: touch, pressure, proprioception, vibration
- Spinothalamic tract: pain and temperature
- Lateral Corticospinal tract: motor
a rapid series of alternating muscle contractions in response to sudden stretch
clonus
*seen in UMN disease
what is considered the “pit of of the peach”
subcortical structures bc they are deep within cerebrum
what type of muscle fiber?
- sustains contractions
- lots of mitochondria
- innervated by small alpha neurons
Red
(endurance fibers–> uses a lot of blood supply)
*postural muscles
what part of brain is involved in producing prosody
Right inferior frontal gyrus of non-dominant hemisphere
bundles of axons (white matter) in the cerebrum
- Fasciculus
- Funiculus
- Tract (also in SC)
what cortex is important to the interpretation of sound even though they can still hear
auditory association cortex
part of temporal lobe
examples of what type of motor neuron disease/injury?
Spinal cord injury
ALS (Lou Gehrig’s Disease)
UMN and LMN
what is Wernicke’s area
where we receive language
- responds to angular velocity
- responds to changes in speed of rotation in their plane (anterior, posterior and horizontal)
semicircular canals
kinetic labyrinth
what CN are CNS structures
CN I, II and the retina
describe the visual fields
*each retina is divided into 4 quadrants (hemiretinas)
- The retina can be divided by a vertical line into temporal and nasal hemiretinas.
- The retina can also be divided by a horizontal line into superior and inferior hemiretinas.
* *U/L nasal or U/L temporal
what colliculi have reflex connections to muscles in the head
inferior and superior colliculi
*turn if see or hear something
what is prosody
how we say things
-rhythm, pitch, loudness, intonation, length, emphasis, stress, frequency, duration, tones (musical qualities of speech)
describe the monosynaptic reflex
a sensory receptor such as the muscle spindle is activated. The afferent fiber synapses with and excites an alpha motor neuron in the anterior horn of the SC. The alpha motor neuron synapses in the muscle that contains the sensory receptor that was activated and elicits a contraction
ex. patellar tendon reflex
the principal midbrain nucleus of the auditory pathway
inferior colliculi
what part of brain is involved in comprehending prosody
Right posterior temporoparietal regions of non-dominant hemisphere
Describe where the CBs of 1st, 2nd, and 3rd order neurons are in the DCML
1st- in DRG
2nd- in Medulla (fasciculus cuneatus synapses on nucleus cuneatus and fasciculus gracilis synapses on nucleus gracilis)
3rd- in thalamus
Upper visual field→
inferior hemiretina
signs of UMN disease
- decreased strength
- increased muscle tone* and stretch reflexes
- MILD atrophy
- clonus, babinski reflex
describe the afferent and efferent limbs in the pupillary light reflex
-Afferent limb: CN II–> Synapse bilaterally at superior colliculi–> Efferent limb: CN III
Describe a Nissel Stain
- Bottom of image is anterior
- H = gray matter (lumbar and cervical cord have larger gray matter)
- white matter is stained purple
what limb of what CN controls direct and consensual light reflex?
afferent limb of CN 2= direct
efferent limb of CN 3= consensual
*synapse bilatearlly at superior colliuli in midbrain
right-left reversal between visual fields and retinal quadrants
inversion
Central vision of right eye and peripheral vision of left eye go to ___
right occipital cortex
what lobe receives visual stimuli, but doesn’t process it much
occipital lobe
loss of pain and temperature bilaterally indicates a lesion where?
ventral white commissure
*bc this is where spinothalamic tract decussates
where do 2nd order neurons go after the substantia gelatinosa
Sends collateral branches to the Peri-aqueductal grey
interference w/ passage of sound waves through the external or middle ear
(occus w/ obstruction of external auidtory meatus, otosclerosis, otitis media)
conduction deafness
describe the crossed extension response in the flexor withdrawl reflex
The signal from the interneuron also decussates to the opposite leg to activate extensor muscles while inhibiting flexor muscles in order to ensure balance and support
what CN are associated w/ the pons
CN 5, 6, 7, 8
-ear, face, and vestibular
what are the main functions of the frontal lobe?
Motor, Executive functions, Higher cognition for planning of behavior, Planning movement/cognition
gray matter that surrounds cerebral aqueduct
Periaqueductal gray
where is Wernickes area (damage to this area results in Wernickes aphasia)
posterior part of left superior temporal gyrus, inferior parietal lobe
where is the termination point of the spinothalamic tract
Postcentral gyrus of the Somato-sensory Cortex
what areas of the brain influence/stimulate UMN?
Cerebellum
Association cortex
Basal ganglia
what visual field defect presents as contralateral homonymous hemianopsia (blindness in the field of vision contralateral to the lesion)
damage of Optic tract, lateral geniculate body, optic radiations, or visual cortex on the right side (i.e. stroke)
what is sensory aprosodia
- Difficulty comprehending the emotional content of speech or gestures of others
- Inability to pick up meaning of sarcasm, inuindos, sense the urgency in what your asking, etc
*more posterior regions on the right hemisphere
Left hemisphere usually controls what?
language, calculations, Rt visual field
why do teenagers struggle with executive function?
pre-frontal cortex of frontal lobe is the last area of cortex to myelinate/finish development (happens between 25 - 32yo for men)
where is the primary motor area?
precentral gyrus
part of frontal lobe
axons from left halves of 2 retinas terminate where?
in left lateral geniculate body–> Left hemisphere
consists of 2 hemispheres; 3rd ventricle space is between hemispheres
cerebrum
what is gray matter
cell bodies
- form nuclei when a large number are grouped together
- can stain white
damage to Parietal-temporal-occipital association area could result in
word blindness with writing impairments: can see everything but words
where do 3rd order neurons go after the thalamus
Branches can be sent to the reticular formation and the hypothalamus leading to emotional response
posterior horn consists of ___ and anterior horn consists of __
posterior- sensory (substantia gelatinosa)
anterior- motor (LMN/alpha MN and Gamma MN)
problems w/ taste is due to damage to what areas of the brain?
brainstem, thalamus, or cortex
where is the decussation of the spinothalamic tract
2nd order neuron at the ventral white commissure
what is the pupillary light reflex
light directed into either eye causes both pupils to constrict
(direct and consensual pupillary light reflex)
where is the decussation of DCML?
2nd order neuron in low medulla via the internal arcuate fibers
what are the main roles of the temporal lobe? (4)
- hearing
- memory
- speech
- emotional responses
important white matter areas (4)
- Corpus callosum
- internal capsule
- Fasciculus cuneatus and gracilis
- Anterior white commissure
what part of the brain controls prosody
Function on non-dominant hemisphere (right side for most people)
- Right inferior frontal gyrus involved in producing prosody
- Right posterior temporoparietal regions comprehend prosody
presents with:
- expressive aphasia
- syntax may remain intact
- decreased fluency
lesion in brocas area
how do you test for parietal lobe function?
Tested by proprioception, light touch, sharp vs dull, stereognosis
where is broca’s area and why is it important?
frontal lobe (44, 45) (typically left hemisphere anterior to Wernicke) -"speech center"-- where we produce written and spoken language
Lamina of Rexed (I-X) is ___ matter
gray
what is the cause of parkinson’s
- Degeneration of substantia nigra (midbrain)
- Loss of dopamine producing cells (esp. in basal ganglia–> Interferes with the normal disinhibitory pathways from basal ganglia to thalamus to motor cortex)
- Imbalance of neurotransmitters
a diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness
reticular formation
*projections from spinothalamic tract
Nasal visual field→
temporal hemiretina
(white matter only found in the brainstem)
cerebellar peduncles
4 inputs to cerebral cortex
- association fibers-from other regions of same hemisphere
- commissural fibers- from regions in contralateral hemisphere
- projection fibers- from thalamus
- diffuse projections of ARAS- from RF
what do muscle spindles and GTOs detect?
muscle spindles- muscle lenghth
GTO (golgi tendon organs)- muscle tension
Presents with:
- Diminished abilities i.e. negative with somatosensory perception
- If considerable damage (like with neglect) and extends into other areas, may have neglect (inability to even consider contralateral side especially L side such as they don’t even know it exists and can’t feel anything)
parietal lobe lesion
You are walking barefoot in the back yard. You step on a sharp rock with your right foot. What reflex will respond
flexor withdrawl
what do CVA usually affect?
- lesion of contralateral corticobulbar and corticospinal tracts
- Likely internal capsule or ventral pons
what are colliculi?
masses of cell bodies
-4 pairs of superior and inferior
Projection fibers that descend from brain, to the brainstem and spinal cord; or ascend from lower centers to the cerebral cortex
internal capsule
*made of white matter
presents with:
- Loss of self-control
- Euphoria-unrealistic sense of happiness
- Difficulty shifting from one mental activity to another
- Perseveration: holding on to same thought over and over
- apathy (disengaged)
- NO motor or sensory rxns
- no speech disturbances
prefrontal lobe lesion
**like following a stroke or Alzheimer’s
damage to CN 6 (abducen) results in
medial strabismus
-diplopia
*lateral rectus paralyzed
where do ascending tract projections go to in thermoregulation?
somatosensory cortex
and hypothalamic centers
what visual field defect presents as bitemporal heteronymous hemianopsia (blindness in the nasal half of the retina or the temporal half of the visual field of each eye)
damage of optic chiasm
aka tunnel vision
what is visual agnosia
Person can see but they don’t know what they are seeing
the man who mistook his wife for a hat
describe how the upper and lower face are innervated
- left lower face–> innervated from contralateral hemisphere
- upper face–> recieves input biltareally (contralateral and ipsilateral innervation) so upper face is typically spared in a stroke
describe the motor homunculus
primary motor area (frontal lobe)
- disproportionate representation of the hand
what type of muscle fiber?
- fewer mitochondria
- contract in brief, powerful twitches
- larger
- innervated by large alpha neurons
white
ex. quads, gluts, pecs
what visual field defect presents as blindness in one eye
optic nerve damage
“in-between brain”
“little brain”
diencephalon
cerebellum
Lesion here makes spoken language difficult to understand
auditory association cortex
part of temporal lobe
what are the main parts of the ventricle system?
anterior horn, body, posterior horn, inferior horn
Dorsiflexion of the big toe and fanning of the others in response to firmly stroking the sole of the foot
babinski
*seen in UMN (GOLD STANDARD!!)
where is a lumbar tap done?
Lumbar cistern
*SC terminates at L 1/2
describe the flexor withdrawl reflex
- Mechanoreceptors triggered by deformation.
- A-delta afferent fibers transmit a signal from the sensory receptor to the SC
- A-delta afferent fibers synapse at an interneuron in SC
- An alpha motor neuron transmits signal from the SC to the neuromuscular junction.
- The signal from the alpha motor neuron results in excitation of flexor muscles while inhibition of extensor muscles.
how many pairs of CN are in the PNS?
10 pairs since CN I and II are outgrowths of the CNS
supplementary motor area controls
role in planning, learning complex internally generated movement
operates learned and repetitive motor skills (i.e. shoe tying, playing music) AKA muscle memory
cerebellum
bundles of axons (white matter) in the brain stem
- Lemniscus
2. Peduncle
describe the visual pathway
Photoreceptors→retinal ganglion cells (CN II)→optic chiasm→partial decussation→(now blended fibers) optic tract→lateral geniculate nucleus (relay for vision in the thalamus)→optic radiation→primary visual cortex
what are receptor types of DCML
muscle spindles, GTOs
what is Kluver-Bucy Syndrome
- Bilateral destruction of amygdaloid bodies and inferior temporal cortex
- Resultant emotive behavioral changes (emotional blunting, hyperphagia, inapproriate sexual behavior, visual agnosia)
what is the function of the primary somatosensory cortex in the parietal lobe
Initial cortical processing of tactile and proprioceptive information
- major nuclei; largest area/nuclei
- Contains cell bodies clumped together to form nuclei
thalamus
*Grand central station
4 Basal ganglia examples
- Striatum (caudate and putamen)
- Globus pallidus
- Substantia nigra
- Subthalamic nucleus
axons from right halves of 2 retinas terminate where?
in right lateral geniculate body–> visual cortex of Rt hemisphere
Explain spinal shock
Spinal shock results from sudden transection of the SC
-the areas of the body that is innervated by the SC segments below the level of the lesion lose neural activity. There is lack of DTR sensation, muscle tone, and movement at and below the level of damage
why does LMN disease have severe atrophy?
bc final common pathway has been severed (UMN there still may be others connecting to final common pathway)
what are the main functions of the parietal lobe?
somatic and vision sensory processing
w/ weber test, hearing in unaffected ear is more sensitive
unilatearl nerve deafness
what labyrinth?
responds to acceleration and head tilts (right/left, back/down, acceleration/deceleration in horizontal and veritcle plane)
Static Labyrinth
urticle and saccule (otoliths)
describe the parts of the medulla
- bottom part of brainstem
- Pyramids= motor (ventral) tracts
- Anterior median fissure
- Anterolateral sulcus or preolivary
in left handed people, are the percentages of hemisphere dominance?
- 70% L
- 15% R
- 15% equally dominat
premotor area controls
role in planning movement
guided by external/visual stimuli ie. reaching for an object
Largest bundle of commissural fibers connecting left and right hemispheres
Corpus callosum
*made of white matter
what is broca’s area
“speech center”
-important in the production of written and spoken language
describe thermoreception
- warm and cold Rs fire continuously (2-5 spikes / sec) at ~36 c
- Warmer→ warm Rs become more active and cold Rs become less active
- Colder→ cold Rs become more active and warm Rs become less active
describe the prognosis of parkinsons
- chronic, progressive neurological disease
- Leading causes of death = pneumonia and falls
what are warning signs of a CVA
- Sudden numbness or weakness of the face, arm, or leg especially on one side of the body
- Pure motor hemiparesis
- upper facial muscles innervated by CN VII bilaterally
describe why in Brown-Sequard syndrome you get loss of pain and temp on one side and loss of fine touch on the other
Pain and temperature is lost on the contralateral side of the hemisection bc the Spinothalamic tract decussates in the ventral white commissure at the level of the spinal cord. Fine touch and motor function is lost on the ipsilateral side bc those tracts don’t decussate until the level of the medulla
the primary motor area/ precentral gyrus is the origin of what?
Corticospinal tract, corticobulbar (to brain stem), and corticopontine
(Corticopontine tracts carry efferent copies that synapse in cerebellar)
(Flaccid paralysis)
-Where polio virus roots are
LMN aka alpha motor neurons
in anterior horn
causes of gustatory anesthesia
- smoking
- CVA affecting taste regions of thalamus or gustatory cortex
- CN 7 lesion (Bell’s Palsy)
- CN 9 lesion
- disease of middle ear
what manifestations would result from a parietal lobe lesion?
- Diminished abilities i.e. negative with somatosensory perception
- loss of discriminative sensibility
what connects the 3rd and 4th ventricle and where?
cerebral aqueduct connects 3rd and 4th ventricles at the level of the midbrain
what is motor aprosodia
- Unable to convey feeling by voice or gesture
- Feelings are there!
ex. School teacher who had difficulty controlling students, unable to express authority by voice or gesture
*right frontal damage
what CN innervate the tongue and are involved in taste?
CN 7, 9, 10
- Cell bodies that relay pain and temperature information
- Significant because analgesics inhibit synapses
Substantia gelatinosa (in posterior horn)
what are the cardinal signs of parkinson’s disease?
- tremor (resting or pill-rolling)
- rigidity (increased resistance to passive movement)
- bradykinesia ( slowness of movement)
- postural instability (shuffling gain w/ decreased arm swining)
- mask-like fascies
what are the 6 main structures of the limbic system
- Amygdala
- Hippocampus
- Parahippocampal gyrus
- Cingulate cortex
- Orbitofrontal cortex
- Insular cortex
craniopharyngioma (tumor of the pituitary gland) often causes
tunnel vision
- damage of Optic chiasm→ bitemporal heteronymous hemianopsia
- Upper visual fields project to _____
- Nasal visual fields project to ____
- lower retinal quadrants
- temporal retinal halves
* due to inversion
how do differentiate from Bell’s Palsy and a CVA
-person w/ Bells Palsy will NOT be able to lift eye lid
describe the pathway of UMN
cortex—> internal capsule–> ventral brainstem–> decussates at level of the pyramids–>descends SC–>synapses on ventral grey horn w/ LMN
bundles of axons (white matter) in the periphery
Nerve
presents w/
-Disturbance of auditory sensation and perception
(But hearing is bilateral in the brainstem, so loss in auditory region doesn’t affect as much)
-Disturbance of language comprehension
-Altered personality and affective behavior
-Impaired Long-Term Memory
temporal lobe damage
Loss of peripheral visual fields but central maintained because it is projected to the temporal retinal fields and doesn’t decussate
tunnel vision
- damage of Optic chiasm→ bitemporal heteronymous hemianopsia
what is white matter
myelin, axons, form tracts
Spontaneous contractions of groups of muscle fibers, visible through the skin as small twitches
fasciculation
*seen in LMN disease
describe the afferent and efferent limbs of the corneal blink reflex
- Afferent limb CN V Trigeminal
- Efferent limb CN VII Facial
- connections made bilaterally in the reticular formation (level of brainstem)
temporal visual field–>
nasal hemiretina
Right visual field goes to the left retinal field/nasal retina
what happens with a lobotomy or lesion of the pre-frontal cortex?
- Loss of self-control
- Euphoria-unrealistic sense of happiness
- Difficulty shifting from one mental activity to another
- Perseveration: holding on to same thought over and over
- apathy (disengaged)
* *like following a stroke or Alzheimer’s
what is NOT effected in pre-frontal cortex damage?
Destruction of this region does not result in paralysis nor paresis, nor does it produce disturbances of speech or sensation (bc does not produce motor or sensory rxns)
describe sx of a CVA
- UMN
1. Heightened reflexes
2. Babinski sign - Sudden confusion, trouble speaking or understand
- Sudden visual disturbance/trouble seeing in one or both eyes
- Sudden trouble walking dizziness, loss of balance
- Sudden, severe headache with no known cause
in a multisynaptic reflex what does activation of the GTO result in
excitation or inhibition to antagonist muscles
what does the brainstem consist of
midbrain, pons, medulla
what is the purpose of the corneal blink reflex?
moistens and cleanses cornea
- protects against injury and infection
what controls the initiation of voluntary movement
primary motor area
CN 8:
cochlear division responds to __
vestibular division responds to __
cochlear division responds to sound
vestibular division responds to movements of head
*via hair cells
term used for the alpha motor neuron through which are funneled all impulses from multiple sources to the skeletal muscle
final common pathway
what are parts of the efferent limb in the pupillary light reflex?
- Medial, superior, inferior recti
- Inferior oblique
- Levator palpabrae
- Pupillary sphincter; ciliary muscle
describe the polysynaptic reflex
a sensory receptor is activated and afferent fibers synapse with and excite an alpha motor neuron in the grey matter of the SC. The afferent fibers will also synapse with interneurons in the grey matter of the spinal cord. The alpha motor neuron will excite flexor muscles while also decussating to muscles on the contralateral side in order to maintain balance by exciting extensors. The interneuron can be excitatory or inhibitory. With inhibitory interneurons, they inhibit contraction of muscles of antagonistic actions
where is the primary somatosensory cortex
post central gyrus on the parietal lobe
damage to Rt frontal lobe motor areas (primary, premotor, SMA) results in
Contralateral Paralysis
role with memory as do temporal lobes (why short term memory loss is common with trauma
mammillary bodies
how do you test to see if a SC injury is complete or incomplete?
evaluate Bowel, bladder, and genital function bc it is controlled by most distal spinal cord (S4/S5)
what is in the intermediate grey
ANS
- T1-L3, preganglionic sympathetic
- S2-S4, preganglionic parasympathetic
- Integrates functions of respiration, consciousness and complex motor patterns
- Loosely defined network of neurons in the core of the brain stem
reticular formation
*receives input from almost everything!
what are the main functions of the limbic system
- Emotion (particularly fear based)
- memory
- drive related behavior