Neurology For Exam 1

What is the subcortex?

a term referring to all brain structures below the cerebral cortex

Where are the ventricles located?

in the subcortex

what many ventricles do we have

4 total

2-lateral

1-thirds that connects the two lateral onces

1-between the cerebellum and the brainsteam

what are ventricles filled with

cerebrospinal fluid (CSF)

what is the 3 purposes of CSF

1) cushions the brain

2) delivers nutrients to the brain

3) removes waste products

where does CSF come from

it is produced by choroid plexus cells found in each ventricle

how much CSF do we produce a day

500 mL

where deos CSF go

within the ventricles, flows around the brain and in and around the spinal cord, it also goes to our blood

where does CSF exit

drains into the sub-arachnoid system and enters the venous system

what is the flow of CSF

produced in the chorid plexus

then goes to the subarachoid space (around the brain and spinal cord)

to the venous system (in the blood stream)

what causes CSF to be blocked

trauma, edema (swelling), tumors

what is a CSF blockage called

normal pressure hydrocephallus

what is normal pressure hydrocephallus

a type of reversable dementia

becomes reversable when you remove large amounts of CSF

what are the 3 symptoms of normal pressure hydrocephallus

1) declining memory

2) incontinece (not being able to control you bladder)

3) altered gait (you walk funny)

what does normal pressure hydrocephallus look like in a MRI

very large ventricles

corona radiata

white matter tracts that flow into internal capsule

if you had a stroke at the internal capsule, what would be effected

all motor comands

could become paralyzed

if you had a stroke in the cortex, what would be effected

only the specific motor movement damaged by the stroke

what could injuries in the cortex cause

cognitive impairments, language issues (aphasia), planning problmes (apraxia of speech), focal (specific) motor disorders

what could injuries in the corona radiata cause

(many) motor movement impairments on the contralateral side to where the stroke occured

an impairment of the working memory is impacted by

damage in the cortex

parkinsons happens due to injury of the

subcortex

not being able to understand speech is caused by an impairment to the

cortex

not being able to produce speech is caused by an impairment to the

cortex

if someone has paralysis to the right side without impairments of language or cognitive abilities it is injury of the

sub-cortex on the left side

deep brain stimulation (DBS)

electrical stimulaiton to deep areas in the brain (subcortex)

What does DBS treat?

parkinsons, tremors

thalamus

sensory relay station

has two left and right thalami

most medial of the subcortical structures

what are the two jobs of the thalamus

1) motor movements

2) sensory relay station

thalamus and motor movements between basal ganglia and motor strip

takes indirect (extrapyamidal) instructions to the cortex

this inhibits other movements from taking place (parkinsons is this on steroids)

thalamus and motor movements between cerebellum and the motor strip

takes "error corrections" from the cerebellum (balance) to the motor strip

sensory relay station

sends sensory infromation to the specific areas in the brain

all senses except for smell

what two diseases involve movement

parkinson's disease (restricted movement)

huntington's chorea (lots of movement)

Basal ganglia

collection of 5 nuclei that influences movement (does not cuase it)

where is the basal ganglia located

deep in the cerebral hemispheres and the brainstem

where does the basal ganglia receive information from

the cortex

direct pathway of basal ganglia

responsible for making all volunary movements

relys on dopamine to excite

basal ganglia is less involved (simplar)

indirect pathway of basal ganglia

responsible for preventing unwanted movements from hindering voluntary movements

relies on dopamine to supress movements

basal ganglia is more involved (complex)

what other structure does the basal ganglia inhibit

thalamus (limits its encouragment of movements)

what are the symptoms of Parkinson's disease

Bradykinesia

resting tremor

postural instability

Shuffling gait

What is bradykinesia?

slow movement

Symptoms of Huntington's Disease

Chornic movements

cognitive degeneration

psychiatric dysfunction

swallowing

how does one get Huntingtons

Genetically (50% chance of parent giving it to offspring if they have the disease)

3 key parts of the limbic system

cingulate gyrus

amygdala

hippocampus

what is the purpose of the limbic system

motivtation, emotional behavor, sexual drive, long term memory formation and retreival

what is the purpose of the cingulate gyrus

connects emotions with actions

Bridge between limbic system to frontal lobe

what is the purpose of the amygdala

fear and anxiety processing center

what is the purpose of the hippocampus

file clerk of memory, filling new inforamtion and retreving old memories, attention, and navigation throught space

what is another name for the hippocampus

seahorse

cortical spinal tract

on the top part of the cortex

contralateral

one nerve controls each specific movement

cortical bulbar tract

on the side of the cortex

bilateral

more protective since two nerouns control each thing

working memory (short term memory)

remembering temporary information long enough to make a decision or complete a task

declaritive memory

memory for factual information: names, faces, dates

where does decplaritive memory happen

in the hippocampus

procedural memory

A type of long-term memory of how to perform different actions and skills. Essentially, it is the memory of how to do certain things.

where is prodecural memory located

basal ganglia

Alzeimers

loss of declaritive memory

procedural lasts longer

eposodic memory

Memory of personal experiences of specific events in time the memories you fight over

what disease affects the hippocampus

Alzheimer's

cingulate gyrus

carries that limbic system's informaiton to the prefrontal cortex

what is another name for the cerebellum

little brain

what is the primary job of the cerebellum

smooth and accurate movements

what is the secondary job of the cerebellum

cognition, motor skills, language, attention, and emotional regulation

how many neurons are in the cerebellum

50% of the brains neurons

what is the % of volume that the cerebellum occupies

10%

where is the location of the cerebellum

in the skull base (posterior cranial fossa)

below cerebrum

posterior to the brain stem (by the 4th ventricle)

what level does the cerebellum opporate

at the unconscious level

what does the cerebellum detect

errors in movement

Is the cerebellum ipsilateral or contralateral?

ipsilateral

it has two hemispheres

no crossing over (the left hemisphere controls the left foot)

anterior lobe of cerebellum

forms the superior 1/3rd of the cerebellum

receives proprioceptive information

posterior lobe of the cerebellum

forms that inferior 2/3rds of the cerebellum and is further subdivided into lobules

controls widespread coordination, espicially lower extremities

flocculonodular lobe of cerebellum

a smaller lobe tucked under the posterior lobe

receives information from vestibular system

vermis of cerebellum

connects cerebellar hemispheres

looks like a worm

arbor vitae of cerebellum

white matter of the cerebellum; looks like branching fern when cut

inferior cerebellar peduncle

connects the cerebellum to the medulla ablongata

middle cerebellar peduncle

connects cerebellum to pons

longest of the three peduncles

superior cerebellar peduncle

connects cerebellum to midbrain and to the red nucleus and thalamus

what are the three steps in the cerebellum motor plan

1) receives the motor plan (input)

2) provided with correct proprioception information from the body (input)

3) carries out adjustments/corrections to the motor plan (output to the cortex)

signs of damage of the cerebellum

ataxia, nystagmus, tremor, dizziness, dysdiadokinesis, dysarthria, dysmetria

what is ataxia

poor muscle control with movement

what is nystagmus

involuntary eye movement

what is dysdiadokinesis

inability to perform rapid alternating movements

what is dysarthria

motor speech disorder impact of execution of plan

what is dysmetria

overshooting, undershooting of movements

does cerebellum damage cause weakness

no

causes of cerebellar decline

degenerative diseases, tumor, trauma, stroke

how to recover from deep cerebellar injuries

typically they are long lasting, chronic, and not treatable

how to recover from superficial cerebellar injuries

they can improve with time and therapy

what is the difference between the cerebellum and the basal ganglia

cerebellum: controls ongoing adjustments, revision of the motor plan to achieve a smooth and accurate result

basal ganglia: controls timing and initiation of direct and indirect muscles/movements

what does innervation mean

brining nervous energy to muscles

contralateral innervation

providing innervation to the opposite side of the body (decussation)

what is neuro implication for contralateral innervation

a stroke in the right hemisphere will impact the left side of the body

bilateral innervation

providing innervation to both sides of the body

what is neuro implications for bilateral innervation

injuries to one side of the brain have less of an impact because there is two ways those muscles are getting energy

example of contralateral innervation

all spinal nerves (31)

example of bilateral innervation

most of the cranial nerves (except lower face and tongue)

corticospinal tract

decussates in the lower medulla at a location called the pyramids

what % of fibers cross over in the cortiospinal tract

75-90%

what is the pathway of the cortiocspinal tract

IF YOU WANT YOUR RIGHT FOOT TO MOVE

message starts in the left hemisphere, then it travels on the corticospnal tract until it gets to the medulla where it decussates before going to the spinal cord

then it synapese with a motor neuron

corticobulbar tract

decussates just above the point of synapses with a cranical nerve

more complex (redundant than the corticospinal tract)