Test 3 Flashcards
Importance of structure
tells us a lot about function
-complexity of human cerebrum surface
-size of olfactory bulb (ie rat v humans)
seeing into the brain- hitoryically what was used
disection and staining
new technologies allows us to see living brains- structural
-computed tomography (CT or CAT)
-magnetic resonance imaging (MRI)
new technologies allows us to see living brains- functional
-positron emission tomography (PET)
-Functional MRI (fMRI)
new technologies allows us to see living brains- other techniques and advancements
-Diffusion tensor imaging
-improving MRIs
Structural- comuted tomography (CT or CAT)
Digitally reconstructed x-ray images
-360 degrees to provide slices of the object
Structural- comuted tomography (CT or CAT)- PROS
-can see bone, brain, organs, ect
-great for bleeding and tumors
–quick scan
-lower cost and shorter wait times than MRI
Structural- comuted tomography (CT or CAT)- cons
-low doses or radiation
-images may not be as detailed as other techniques
Structure- magnetic resonance imaging (MRI)
(m aslo stands for magic)
-no radiation, just large magnetic feild
-different atoms interact differently within the magnetic feild
-build a “map” based on this
-Stronger magnet= clearne images. rated as tesla units (0.5T-3T)
-provides slices of images based on the specific sequences of the scan
Structure- magnetic resonance imaging (MRI)- pros
-no radiation
-great view of soft tissue
-can highlight different types of tissue (two types: T1-denser vs T2-flags high H20 content like CSF)- depends on what you want to look at
Structure- magnetic resonance imaging (MRI)- cons
-longer scan times
-can be noisy
-metal implants may cause issues
-longer wait times and more expensive
-mangnet can be dangerous- the magnet is always on; anything metal gets sucked in
clinical case- what is the best way to see MS lesions
MRI is the best way to see lesions
Preffered diagonstic technics
-Symtoms + imaging and other tests needed
-can identify previous damage, new imflammation and even atrophy over time
Functional- positron emission tomography (PET)
Iaging with radioactive tracer (injected into the body)
Can be used with CT or MRI
-IV with tracerand compounds used by the bodyn(eg glucose-neurons use more when active, pull in tracer with glucose so can track activity)
-measures metabolic activity of the cells of body tissues
-used to diagnosed brain disorders, cancers, ect
Functional- positron emission tomography (PET)- flurodopa
type of dopa with radioactive tracer
-Used to detect damaged or lost domapinergic neurons
-support the diagnosis and the evaluating progression and treatment
tracer is injected, brain needs to use dopa. As use it, accumuate tracer- helps detect dopaminergic neuron damage
RTC looking at stem cells for PD
uses PET scans to look at dopaminergic cells
-embryonic dopa (stem cells)
-injected into brain–> hope it turned into dopaminergic neurons
some RTC show it improves vs controls (where less flurodopa is picked up)
Functional- Functional MRI (fMRI)
MRI to measure changes in blood flow
-Increased blood flow means increased neural activity
-no injection required and better resolution than PET
-track changes in blood flow (increases or decreases) using MRI
-Used to map brains for surgery, diagnose disease and provide many research opportunities
New technologies- diffusion tensor imaging
Visualizes large bundles of axons in the brain
-uses an MRI to compare the diffusion of eater that occurs along axons
-direction of traces are represented with different colours
-understnad and track the changes in the structure of the brain with aging and disease
New techniques- Improving MRIs
Most “new” techniques come in the form of improvements on this technology
-Improving scan times (2-3 minutes–> aeconds)
-Improving resolution of images (>3T)
-segmentation of images (using AI, tracking diseases over time, seeing structures deep in the brain)
-Measuring different things (fluid levels, tissue stiffness, ect)
Anatomical Planes
3 major planes
All 90 degrees to each other
-Sagittal- midsagittal split down the middle
-Frontal (coronal)
-Transverse (horizintal)
Nervous system division
-central nervous system (CNS)
-peripheral nervous system (PNS)
Spinal cord
-conduit of infomration (brain-body)
-spinal nerves
dorsal roots (sensory)
ventral roots (motor)
peripheral nervous system
-nervous system outside the brain and spinal cord
subdivided into:
somatic PNS anf viseral pns
somatic PNS
innervatess skin, joints, muscles
Dorsal root ganglia: clusters of neuronal cell bodies outside the spinal cord that contain somatic sensory axons
visceral PNS
innervates internal organs, blood vessels, glands
Afferent axons
carry to
-cary information towards CNS (ie sensory)
Efferent axons
carry from
-carry information away rom CNS (ie motor)
Collection of neuronal bodies (somas)- gray matter
neuronal bodies in the CNS
Collection of neuronal bodies (somas)- nucleus
mass of neuronal bodies in the CNS
Collection of neuronal bodies (somas)- ganglion
collection of neuronal bodies in the PNS
collection of axons- white matter
collection of axons in the CNS
collection of axons- nerve
bundle of axons in the PNS
collection of axons- tract
collection of axons with a common origin and destination in the CNS
Cerebrospinal fluid (CSF)
-produced by chrocoid plexus found within the brian
-circulates throuout CNS
-absorbs into venous system
CSF functions
-protection
-buoyancy
-excrete waste products
-endocrine medium
lateral ventricles
-Also called 1st and 2nd ventricles
-leragest cavities
3rd and 4th ventricles
-cennected via cerebral aqueduct
-3rd ventricle is between two halves of diencephalon
-4th ventricle posterior to pons and medulla, but anterior to the cerebellum- continues with central canal of spinal cord
Forebrain
-telecephalon (cerebrum)
-diencephalon
hindbrain
-cerebellum
-pons
-medulla oblongata
telencephalon (or cerebrum)
-largest part of human brain
Two cerebral hemispheres
-cerebral cortex (outer layer)
-white matter (3 groupings)
-basal ganglia
-amygdala
-hippocampus
Responsible for a variety of tasks
what is is telencephalon responsible for (tasks)
-higher order thinking/reasoning
-analyse sensory input and command motor output
-memory and emotion
3 major white matter systems in telecephalon
axons extend from developing forebrain to other parts of nervous system
-cortical white matter: axons of the cerebral cortex
-corpus callosum: bridge between left/right hemisphere
-internal capsule: links brain to brain stem
axons come together and run to brainstem via thalamus (2 way street from top to bottom of brain)
diencephalon (thalamus)
-gateway to cerebral cortex
-via the internal capsule
diencephalon (hypothalamus)
-roles in a variety of autonomic functions and hormine release
the midbrain
contains ascending/ descending pathways between cortex, brain stem and spinal cord
-note cerebral aqueduct is in centre
contains: tectum and tegmentum
the midbrain: tectum
receive sensory information from eye/ ears
the midbrain: tegmentum
contains teh substantia nigra (black substance) and red nucleus which help control voluntary movement (connects to basal ganglia)
The hindbrain
contains 3 major structures: cerebellum, pons, medulla oblongata
4th ventricle arises form the cerebral aqueduct
hindbrain: cerebellum
most posterior
-movement control centre
hindbrain: medulla oblongata
most inferior/caudal
-autonomic processes (breathing, blood pressure, ect)
-also relays information to thalamus
hindbrain: pons
most superior/ rostral
-switchboard connectingcerebellum and cerebral cortex
the spinal cord
white matter in outer layer (superficial)
grey matter inside (deep)
spinal cord- extension of 4th ventricle
cerebral cortex: gyri, sulci, fissures
gyri: bumps
sulci: grooves
fissues: deep grooves
cerebral cortex: central sulcus
in the frontal plane
precentral gyrus: voluntary movment (last place before information is sent out)
postcentral gyrus- somatic sensation (where 1st peice of info comes in)
cerebral cortex: lateral fissure
superior temporal gyrus- hearing
aka sylvian fissure
cerebral cortex- 4 primary lobes
-frontal
-parietal (central sulcus)
-temporal (lateral fissure)
-occipital
areas of the frontal lobe: prefrontal cortex
-executive finction- higher cognitive processes for planning (including movment planning) and organizing thoughts, speech, and behaviours
-attention- candirectly or indirectly influence movment
-personality and social behaviour
Areas of the forntal lobe: premotor and supplementary motor area
Brodmans area 6
-preperation of the body movment
Areas of the forntal lobe: primary motor cortex
M1 or brodmans area 4
-precenral gyrus
-generates neural impulses for movment
-somatotopic motor map
-sends info out to spinal cord
somatotopic map
size on map relates to number of neurons
Areas of the parietal lobe: somatosensory cotex
S1 or brodmans area 1-3
-postcentral gyrus
-primary area for processing somatic snesations (raw info coming in)
-Somatotopic snesory map
Areas of the forntal lobe: posterior parietal cortex
brodmans area 5,7
-integrating sensory information
-oject recognition (can recognize feel of object), spatial relationshps, ect
-contributes to planning and organizing action
occipital lobe
visual cortex
-processses visual information
temporal lobe
Auditory cortex
-processes auditory information
Infertemporal cortex
-visual processing and object recognition
object recognition
Visual information passed from visual cortex to inferotemporal cortex
-Quickly and easily identify objects
-Don’t fully understnad it yet
-AI- can’t wquite do it like humans yet but gotten much better in recent years
Thalamus
-Part of the diencephalon (duck head with hypothalamus as the beak)
-3rd ventricle is between R and L halves
-Link between sensory and info and cerebrum
-previously though tto just be a realy station- now know that os processes (excites/inhibits) and directs to specific areas (like an agent or air traffic controller)
-highly integrated with cerebellum and basal ganglia with cortex
-axons travel through internal capsule
-divided into seperate nuclei that project to diferent areas in the cortex
nuceli of the thalamus- Ventral posterior (VP)
-sends snesory inforation to postecentral gyrus
-projects to the postcentral gyrus
nuceli of the thalamus- Ventral lateral (VL)
-sends motor info
-projects to precenrral gyrus
-receives input from basal ganglia (helps fine tune info)
Basal ganglia
group of subcortical nuclei which support the selection and initiation of movment while preventing unwanted movments (amoung other things)
-involves nuceli in the telencephalon, diencephalon (forebrain) and midbrain
Basal ganglia: 4 main nuceli- striatum
receives input from cortex
includes:
-caudate nucelus
-putamen
Basal ganglia: 4 main nuceli- globus pallidus
output to thalamus
-internal and external segments (GPi/GPe)
Basal ganglia: 4 main nuceli- subthalmic nucleus
helps regulate movment
Basal ganglia: 4 main nuceli- substantia nigra
within midbrain
-helps regulate movment- dopaminergic neurons
-degeneration in Parkinson’s disease
Pons
venral to 4th ventricle in the hindbrain
-has lots of ascending and desceding tracts carrying sensory adn motor inforamtion
-contains the pontine nuclei and the pontine reticualr formaiton
pons- pontine nuceli
most ventral aspect
-relays cortical infomration to cerebellum
pons- pontine reticular formation
-important for respiration, taste, and sleep; as weell as postural control
cerebellum- little brain
Most dorsal aspect of the hindbrain
-folia (like gyri), and lobules (like lobes)
-vermis (like corpus callosum) sperates left and right sides
-deep cerebellar nuceli realy information out
-most notable cells- perkinje cells
cerebellum- perkinje cells
vast netweok of dendrites(receives lots info) and one axon
-loss of or damage to movment disorders and/or coordinatiom problems (coordinate and fine tune movments)
damage to the cerebellum
leads to uncoordinated movements (ataxia)
-test using the finger to nose test
cerebellum and alcohol
shrinking of cerebellum wth long term heavy drinking
-alcohol impacts the cerebellum- think of sobriety tests- testing fine movment controlled by cerebellum
