L4: Neuroanatomy P1 Flashcards
Cerebral angiography
angio = blood or lymph vessels
Xray to diagnose blockages or other structural problems in the vascular systems
catheter into femoral artery to carotid artery
contrast dye injected to fill arteries
used in concert w CT or MRI
risks of cerebral angiography
allergic to dye
risk of perforation
renal issues could affect ability to get rid of dye
computed tomography (CT)
3D rep from xray images
patient positioned in a rotating tube while a series of xrays are taken
computer complies the xrays across sectional slices of the brain
able to visualize the brain at diff depths
downsides/risks of CT
poor dx sensitivity for acute ischemic strokes (aka acute changes of soft tissue) - led to use and advancement of perfusion tomography
exposed to radiation
can also be used w dye so risks w that
less sensitive
on a CT white represents…. black represents… grey reps…
white reps high density aka bone
black reps lease dense so SCF
blood is more dense than CSF so it will look more grey
profusion….
hyper profused ….
hypo profused…
uptake of a fluid
hyper = more blood like a hemmorrage
hypo = less fluid in an area
magnetic resonance imaging (MRI)
magnet and radio waves
patient positioned in tube-like machine w a strong magnet
very noise due to clicking noises from radio pulses
MRI seqs typically used clinicially include T1, T2, FLAIR, and diffuse-weighted (dMRI)
dMRI detects infarcts w/i min
allows us to see pathology of soft tissue - more sensitive at detecting stroke than CT
downsides/risks of MRI
very expensive
contrast dye issues
not great for those w claustrophobia or delirium
some may need to be sedated
those w metal implants cannot be used w it
functional MRI (fMRI)
standard MRI technology that produces images of metabolic function
indirect measure of neural activity in the brain and spinal cord during a specific task
used to localize brain functions such as language
used more in research
Positron emission tomography (PET)
3D image of metabolic processes, blood flow, or receptor density
IV injection of a radioactive tracer that travels thru the body and is absorbed by organs
can help detect underlying brain pathology before symps arise like alzheimer’s or PD
on a PET red/orange reps… and blue/green reps…
red/orange = a lot of metabolic activity (aka using lots of oxygen)
blue/green = less metabolic activity
downsides to PET
if the patient already has pathology like a tumour (which would need oxygen a lot) they may have areas that are red to begin w that do not have to do w brain functioning
exposed to radiation (but unlike CT it is transient)
v expensive and not accessible
single-photon emission computed tomography (SPECT)
utilizes gamma-emitting radioactive isotopes
emits a single (rather than 2) photon
isotope administered thru IV
absorption associated w cerebral blood flow (CSF)
2T images taken and them computed into 3D
not as costly as PET, but not as sensitive
electroencephalography (EEG)
measures cortical voltages fluctuations from electrodes placed on the scalp
signals are recorded as a series of tracings reflecting change over time
reveal abnormalities in brain electrical activity
epilepsy dx and management
evoked response potentials (ERP) - EEG + stimulus
great temporal sensitivity (changes at a point in time), but not great spatial sensitivity (cannot localize it)
downsides to EEG
time consuming
if the patient is moving around EEG is vulnerable to eye movements or face movements
not great spatial sensitivity (cannot localize it)
EEG on its own is looking at brain activity at ____ ERP is when you introduce a _____
rest
stimulus (ex. count from 1-10)
magnetoencephalography (MEG)
magneto = magnetic, encephalo = brain, graphy= pictures
measures magnetic fields produced by the brain’s natural electrical currents
can be conducted at rest or w stimulus
often used in concert w MRI to localize brain activity (magnetic source imaging or MSI)
direct measure of brain function
rly great sensitivity for the locus of seizure activity
CNS
cerebral hemispheres, brainstem, cerebellum, spinal cord
PNS
Cranial and spinal nerves + ANS
brainstem
midbrain + pons + medulla
protective layers
skin, muscles, cranium, meningeal layers, CSF, vascular systems
3 meningeal layers
pia = adheres to surface of brain
arachnoid = spider like
dura = adheres to inside of cranium
subdural hematoma
bw dura and arachnoid - can get filled w blood
subarachnoid hemorage
when the subarachnoid space gets filled w blood from trauma - type of stroke
sulci are within a ____
lobe
fissures separate ____
lobes
3 types of fiber tracts
commissural
association
projection
commissural fiber tracts
inter-hemispheric and non-cortical regions (ex. thalamus, hippocampus)
RH to LH
ex. corpus callosum
association fiber tracts
intra-hemisphere
one area w/i a hemisphere to another in the same hemisphere
ex. long association fibres are one lobe to a diff lobe in the same hemisphere
projection fiber tracts
ascending (ex. sensory) and descending (ex. motor)
from brain stem and up (ex. internal capsule)
_______% worlds popn R-handed, ____% of R handers show……
90-95%
95% show L-hemisphere language dominance
_____% worlds popn L-handed, _____% of L-handers or mixed handedness possess L hemisphere dominance, _____% of L-handers or mixed handedness show R-hemisphere language dominance, _____% of L-handers or mixed show bilateral language dominance
7-10%
65-70%
5-10% (!!!!)
20-35%
coronal
vertical - belly and back
saggital
vertical
left and right
transverse/axial
horizontal
head and toe
frontal lobe contains brodman’s area ___ and ___ or Broca’s area
44 and 45
Brodmann’s area 44/45 and Broca’s area involves
memories of motor patterns for speech production plus grammaticality especially for functor words
Damage to Brodmann’s area 44/45 and Broca’s area results in
non-fleunt output, labroious speech w poor reading aloud skills and poor repetition
oftent co-exists w apraxia of speech and nonverbal/oral apraxia
frontal lobe also contains BA 4 which is the
primary motor area (precentral gyrus)
BA 4 - primary motor area involves
motor homunculus
legs and feet are medial side; upper head, face, hands and mouth on lateral aspect inverted
large area of face, and hands laterally
voluntary movements for the contralateral side of body
damage to BA 4 - primary motor cortex would manifest as
UMN dysarthria
frontal lobe also contains B6 and parts of 8 which is the
premotor cortex (inferior lateral)
BA 6 - premotor cortex - stimulation results in…
movement but greats amount of stim are necessary to produce some degree of movement
Parts of BA 6, 8 and 9 are the
frontal eye field
BA 6, 8, 9 - Frontal eye field controls…
conjugate eye movement (eye scanning, the ability of eyes to track and work together) independent of visual stimuli, especially toward contralateral side
exner’s area is a part of the
frontal lobe
Exner’s area (BA 6, parts of 8/9) contains the
foot of 2nd frontal gyrus
knowledge of how to make movements of the hands and fingers for writing
damage of exner’s area linked to
motor agraphia
supplementary motor area is a part of the ______, anterior to the ____ and superior lateral and medial surface of ___
frontal lobe
anterior
BA 6
SMA is involved in
initiation of spontaneous speech and partial complex movements of upper limbs including fingers, arms, and limbs
particularly involved in sensorimotor planning of movements and cog aspects of movement prep (ex. tongue elevation vs protrusion)
damage to SMA …
some suggestions regarding its involvement in stuttering and in speech prod and other motor behaviours
issues initiating speech
prefrontal cortex is ___ to precentral areas and includes BA ….
anterior
BA 8, 9, 10, 11, 12, 46
Prefrontal cortex has numerous association efferent and afferent fiber pathways w
thalamus, hypothalamus, corpus striatum and other areas of cerebral cortex
prefrontal cortex is involved in
executive functions –> initiative, emotionality, regulatory of depth of feelings, role of judgment, attention
superior temporal gyrus - BA41/42 is the
primary auditory cortex
hesch’s gyrus
transverse temporal gyri
superior temporal gyrus aka primary auditory cortex/Hesch’s gyrus is where…. it receives projections from ….
perception/recognition of complex auditory stimuli (ex. speech) occurs
receives projections from the medial geniculate bodu
damage to superior temporal gyrus leads to
auditory verbal agnosia or pure word deafness
in the temporal lobe there is also BA 22 - wernicke’s area which is the _______, and it is involved in
auditory association cortex
connects via arcuate fasiculus to BA 44/45
recall and interpretation of spoken language
damage to wernicke’s causes
difficulty interpreting speech
auditory comp impairment
BA 39 - angular gyrus is responsible for
storing symbols for reading, writing, and calculations/arithmetic
processes orthographic word forms and abstract word forms
receives rich visual projections from visual cortices
damage to the angular gyrus causes
issues w accessing and interpreting symbols needed for reading/writing/math
alexia, agraphia, acalculia
jargo aphasia (if in conjunction w BA 22)
conduction aphasia (if in conjunction w arcuate fasciculus)
Left inferior frontal gyrus linked to ______ (temporal lobe surgery, stroke)
naming deficits
damage to the anterior temporal lobe (BA 20, 21, 38) leads to
impaired semantic knowledge
impaired processing of vowl-change verbs (sleep-tight, keep-kept, dive-dove)
damage to the posterior temporal lobe (BA 37) leads to
difficulty accessing phonology
impaired phonological form access (eg. hat for cat)
arcuate fasciculus is important bc
it is a projection fibre from temporal to parietal to frontal
damage to this will result in issues (ex. repeating someones message) due to connectivity
parietal lobe contains BA 40, the supramarginal gyrus which is responsible for
semantic/syntactic/phonological sentence processing
integrates visual and somesthetic input
operates in conjunction w BA 22
damage to the supramarginal gyrus in the parietal lobe may lead to
jargon aphasia (Kertesz)
constructional apraxia
poor gesture use/comp
scanning and reading
BA 3, 1, 2 - post central gyrus of the parietal lob is the ______ cortex, and receives ______ afferent info ….. before this info gets here it goes thru the ______
primary somesthetic cortex
ipsilateral/contralateral
thalamus
BA 5/7 secondary somesthetic area/somesthetic association cortex in the parietal lobe receives input from …
Primary somesthetic cortex and the dorsal portion of the thalamus
BA 5/7 secondary somesthetic area/somesthetic association cortex in the parietal lobe is responsible for
discriminative touch
integration of info about form, position, temporal changes
BA 17 - primary visual cortex in the occipital lobe receives afferent fibers from the _____
lateral geniculate nucleus
in the PVC in occipital lobe - it receives info from the _____ temporal retina and ______ nasal retina
ipsilateral (aka stay on the same side)
contralateral (aka cross over at the optic chiasma)
in the PVC - the right half of the visual field goes to
L visual cortex
in the PVC the L half of the visual field goes to the
R visual cortex
right homonymous hemianopia
right being right side of each visual field
homonymous = the same
hemi = half vision
BA 18, 19 Visual association cortex receives afferent fibres from ____ and _____
PVC
Pulvinar of the thalamus
visual association cortex is responsible for
real time integration of past visual experiences w recognition and interpretation of what is received thru visual sensory inputs
damage to visual association cortex leads to
visual agnosia (colour, face, objecy), alexia without agraphia
agnosia is
percept or perception stripped of its meaning due to disconnection bw primary sensory cortex and association cortex OR damage to association cortex
can receive and describe the info but can’t interpret it
ex. may be able to see the characs of the photo but not recognize that it is Donald Trump
