Topic 3: Neuroanatomy Foundations Flashcards
How was the brain historically studied
Using dissection and staining after death
What are the two types of structural imaging technologies
- Computed tomography (CT or CAT)
- Magnetic resonance imaging (MRI)
What are the two types of functional imaging technologies
- Positron emission tomography (PET)
- Functional MRI (fMRI)
New imaging techniques and advancements
- Diffusion tensor imaging
- Improving MRIs
Computed Tomopraghy
- Digitally reconstruction x-ray images
-360 degrees to provide slices of the object
Pros of CT
- Can see bone, brain, organs
- great for bleeding and tumors
- quick scan
- lower cost and shorter wait times than MRI
Cons of CT
- Low doses of radiation
- Images may not be as detailed as other techniques
Magnetic Resonance Imaging
- No radiation, just large magnetic field
- Different atoms interact differently within the magnetic field
- build a “map” based on this
- stronger magnet = clearer images (rated in telsa units - 0.5T-3T+)
Pros of MRI
- No radiation
- Great view of soft tissues
- Can highlight different types of tissues (based on type of sequencing T1 vs T2)
Cons of MRI
- Longer scan times
- can be very noisy
- metal implants may cause issues
- longer wait times and more expensive
- magnet can be dangerous (always on)
Application of MRI use with Multiple Sclerosis
- MRI is the best way to see lesions
- preferred diagnosis technique includes symptoms + imaging and other tests
- Can identify previous damage, new inflammation and even atrophy over time
Open MRI
Doesn’t require a full tube
- allows weight-bearing scans
- lower resolution images (0.5T)
Positron Emission Tomography
Imaging with radioactive tracer
- can be used with CT or MRI
- IV with tracer and compounds used by the body (eg. glucose)
- Measures metabolic activity of the cells of body tissues
-used to diagnose brain disorders, cancers, etc.
Fluorodopa
- used to detect damaged or lost dopaminergic neurons
- support the diagnosis and evaluating progression and treatment
- less highlight indicates less active neurons (more cell death)
Functional MRI
MRI to measure changes in blood flow
- Increased blood flow means increased neural activity
- No injection required and better resolution than PET
- Used to map brains for surgery, diagnose diseases, and provides many research opportunities
Diffusion Tensor Imaging
Visualizes large bundles of axons in the brain
- uses an MRI to compare the diffusion of water that occurs along axons
- direction of traces are represented with different colors
- Understand and track the changes in the structure of the brain with aging/disease
Improving MRIs
- improving scan times (2-3 minutes -> seconds)
- improving resolution of images (10T)
- segmentation of images
- Measuring different things (fluid levels, tissue stiffness, etc.)
Anatomical planes
- Sagittal: split into left and right sides
- Frontal (coronal): Splits into front and back
- Transverse (horizontal): Splits into above and below
Spinal cord function and organization
- Conduit of information (brain-body)
- Dorsal roots - sensory
- Ventral roots - motor
Peripheral Nervous System
Nervous system outside the brain and spinal cord
- Somatic PNS: innervates skin, joints, muscles
- Visceral PNS: innervates internal organs, blood vessels, glands
Dorsal Root ganglia
cluster of neuronal cell bodies outside the spinal cord that contain somatic sensory axons
Afferent vs efferent nerves
- Afferent nerves carry information toward CNS
- Efferent nerves carry information away for CNS
Def: Grey matter
neuronal bodies in the CNS
Def: Nucleus (in terms of somas)
mass of neuronal bodies in the CNS
Def: ganglion
collection of neuronal bodies in the PNS
Def: White matter
Collection of axons in the CNS
Def: Nerve
bundle of axons in the PNS
