Week 0 - Preparation Flashcards

Question 1

Q

In general anatomy when the spinal cord and brain are in the same plane, the Quadruped presents four points of direction, these are?

Answer

A

Dorsal (toward the head)Ventral (toward the belly)Rostral (head end)Caudal (tail end)

Question 2

Q

When the brain and spinal cord are at 90degrees (e.g., in humans) what terms are used to describe anatomical directions ABOVE the mid brain?

Answer

A

Anterior (rostral)Posterior (caudal)Superior (dorsal)Inferior (ventral)

Question 3

Q

When the brain and spinal cord are at 90degrees (e.g., in humans) what terms are used to describe anatomical directions BELOW the mid brain?

Answer

A

Anterior (ventral)Posterior (dorsal)Superior (rostral)Inferior (causal)

Question 4

Q

What plane of dissection is parallel to the floor?

Answer

A

Horizontal plane (also known as axial or transverse)

Question 5

Q

What are other names for the horizontal plane of dissection?

Answer

A

Axial or transverse

Question 6

Q

What plane of dissection divide the brain into the front and back (Anterior and posterior) sections?

Answer

A

Coronal sections (also known as frontal sections)

Question 7

Q

What plane of dissection divides the brain into its left and right halves? (general)

Answer

A

Sagittal sections

Question 8

Q

What section divides the brain perfectly/specifically into its left and right halves? (i.e., right in the middle)

Answer

A

Mid-line sagittal section

Question 9

Q

What plane of dissection is divides the brain into left and right halves, but is parallel to the midline (is not the midline).

Answer

A

Para-sagittal

Question 10

Q

How many neurons are in the brain?

Answer

A

Probably more than a hundred billion!

Question 11

Q

What does grey matter consist of?

Answer

A

Predominately cell bodies of neurons Consists of: neuronal cell bodies, neuropil (dendrites and myelinated as well as unmyelinated axons), glial cells (astroglia and oligodendrocytes) and capillaries.

Question 12

Q

What does white matter consist of?

Answer

A

Mostly of glial cells and myelinated axons that transmit signals from one region of the cerebrum to another and between the cerebrum and lower brain centers.

Question 13

Q

How does grey matter differ from white matter?

Answer

A

Grey matter is distinguished from white matter, in that grey matter contains numerous cell bodies and relatively few myelinated axons, while white matter is composed chiefly of long-range myelinated axon tracts and contains relatively very few cell bodies.

Question 14

Q

Where is grey matter found?

Answer

A

Large portions of the outer cerebral hemispheres (the cortex),

Gray matter is also found in large clusters of cells called nuclei located deep within the cerebral hemispheres and brainstem. Examples include the basal ganglia, thalamus, and cranial nerve nuclei.

(In the cerebral hemispheres the gray matter cortex is outside, while the white matter is inside. In the spinal cord the opposite is true: White matter pathways lie on the outside, while the gray matter is in the center)

Question 15

Q

Where is white matter found?

Answer

A

White matter pathways in the inner sections of the cerebral hemispheres (information between inner brain and cortex grey matters)

Brainstem, greater white matter than in the cerebral hemispheres and includes white matter on the outer edges.

Spinal cord, predominately white matter.

(In the cerebral hemispheres the gray matter cortex is outside, while the white matter is inside. In the spinal cord the opposite is true: White matter pathways lie on the outside, while the gray matter is in the center)

Question 16

Q

What is the border between the frontal and parietal lobes called? (two correct names)

Answer

A

<ul> <li>Central Sulcus</li> <li>Rolandic Fissure</li></ul>

Question 17

Q

What is the border between the frontal and temporal lobes called?

Answer

A

<ul> <li>Sylvian fissure</li> <li>Lateral fissure</li></ul>

Question 18

Q

What are the ridges of fissures on the cortex called?

Answer

A

Gyri (plural) or gyrus (singular)

Question 19

Q

What are the spaces between the gyri (ridges) of the cortex called?

Answer

A

Sulci (plural) or Sulcus (singular) or Fissures

Question 20

Q

What is Cytoarchitecture?

Answer

A

(Greek κύτο&sigmaf;= "cell" + αρχιτεκτονική= "architecture"), also known as cytoarchitectonics, is the study of the cellular composition of the body's tissues under the microscope.

Question 21

Q

What are Brodmann's numbers? and what are they based on?

Answer

A

Brodmann’s numbers are acommon way to describe the location of different structures visible on a lateral and medial view.

Brodmann developed the numbering system at the beginning of the last century based on the cytoarchitecture of the cortex

Question 22

Q

What are three dimensions in space? and which planes of dissection do they represent?

Answer

A

Call the three dimensions in space the X, Y and Z “axes”

X represents the left -right dimension (sagittal slices)

Y represents anterior-posterior (coronal slices)

Z represents inferior –superior (horizontal or axial slices)

Question 23

Q

Describe the Talairach and Toumous (1988) dimensional coordinate system.

Answer

A

Define brain regions using axes (X, Y, Z), from a reference point or 'ground zero', which is a midline region of the anterior commisure, one of the white matter pathways that join the left and right hemisphere.

When using Talairach coordinates the patients brain is normalised against a standardised brain. From there it is possible to locate specific brain areas using the Montreal Brain Atlas.

Slices:

•to the right of the AC have positive x values •anterior to the AC have positive y values •superior to the AC have positive z values

EXTRA INFORMATION:

Point 0,0,0 is always found by an intersection between a line joining the inferior aspect of the posterior commisure with the superior aspect of the anterior commissure. A line perpendicular to this through the posterior aspect of the anterior commisure then gives point 0,0,0 where the two lines intersect. Slices to the right of 0,0,0 have positive x values, slices anterior to 0,0,0 have positive y values and slices superior to 0,0,0 have positive z values.

Question 24

Q

How can we define brain regions? (3-ways)

Answer

A

Talairach coordinates

<ul> <li> Example: The FFA is at x = 40, y = -55, z = -10 </li></ul>

Anatomical localization

<ul> <li> Example: The FFA is in the right fusiform gyrus at the level of the occipitotemporal junction </li></ul>

Functional localisation

<ul> <li> Example: The FFA includes all voxels around the fusiform gyrus that are activated by the comparison between faces and objects </li></ul>

Question 25

Q

The initial three bulges or pouches that appear in the neural tube later become the...?

Answer

A

Forebrain (Prosencephalon)

Midbrain (Mesensephalon)

Hindbrain (Rhombencephalon)

Question 26

Q

What components make up the forebrain (Prosencephalon)?

Answer

A

•Telencephalon (cerebral hemispheres - cerebral cortex, subcortical white matter, basal ganglia, basal forebrain nuclei) •Diencephalon (thalamus, hypothalamus, Epithalamus)

Question 27

Q

What components make up the mid brain (Mesencephalon)?

Answer

A

Cerebral Peduncles

Midbrain Tectum

Midbrain tegmentum

Question 28

Q

What components make up the hindbrain (Rhombencephalon)?

Answer

A

Metencephalon

<ul> <li>Pons</li> <li>Pontine tegmentum</li> <li>Cerebellum</li></ul>

Myelencephalon

<ul> <li>Medulla</li></ul>

Question 29

Q

List 6 ways of establishing brain-behaviour relationships (neuroimaging etc)

Answer

A

<ol> <li>Autopsy</li> <li>Using blood supply (e.g., sodium amytal in Wasa test, angiograms</li> <li>Well established structural imaging (CT scan, Magnetic resonance imaging; voxel-based morphometry</li> <li>Well established functional imaging (fMRI, Positron emisson tomography, SPECT)</li> <li>Newer mostly research-based techniques: diffusion tensor imaging, magnetoencephalography, (MEG) transcranial magnetic stimulation (TCMS, C PIB)</li> <li>Distribution and type of intracellular inclusion.</li></ol>

Question 30

Q

Briefly describe the Embroyological development of the CNS (Central Nervous System - i.e., brain and spinal cord)

Answer

A

[Neurulation] During embryological development the CNS arises from a sheet of extrodermal cells that folds over to from the Neural Tube. The neural tube forms several swellings and out-pouncings in the head that eventually develop into the brain, while the part of the neural tube running down the back of the embryo forms the spinal cord. The fluid filled cavities within the neural tube develop into the brain ventricles, which contain cerebrospinal fluid (CSF)

The developing brain has three main divisions: the forebrain (prosencephalon); the midbrain (mesencephalon); and the hindbrain (rhombencephalon)

Question 31

Q

What is neurulation?

Answer

A

the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube. The embryo at this stage is termed the neurula.

Question 32

Q

What is the name for the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube.

Answer

A

Neurulation

Question 33

Q

What is another name for the forebrain?

Answer

A

Prosencephalon ('pro-sen-cefa-lon')

Question 34

Q

What two parts is the forebrain (Prosencephalon) divided into?

Answer

A

<ol> <li>Telencephalon ('Tell-en-cefa-lon') [means "end brain"]</li> <li>Diencephalon ('Dy-en-cefa-lon') [means "across brain"]</li></ol>

Question 35

Q

Which of the three main divisions houses the Telencephalon? AND what components make up the Telencephalon?

Answer

A

Housed in the Forebrain (Prosencephalon)

Includes:

<ul> <li>Cerebral hemispheres <ul> <li>Cerebral cortex</li> <li>Subcortical white matter</li> <li>Basal gaglia</li> <li>Basal forebrain nuclei</li> </ul> </li></ul>

Question 36

Q

Which of the three main divisions houses the Diencephalon? AND what components make up the Diencephalon?

Answer

A

Housed in the Prosencephalon (forebrain)

Includes:

<ul> <li>Thalamus</li> <li>Hypothalamus</li> <li>Epithalamus</li></ul>

Question 37

Q

What is another name for the midbrain?

Answer

A

Mesencephalon ('Mess-en-cefa-lon') [means: "middle brain"]

Question 38

Q

What is the Mesencephalon? What components does it contain?

Answer

A

Midbrain section, a relatively short and narrow region connecting the forebrain and hindbrain.

Contains:

<ul> <li>Cerebral Peduncles (means 'footstalk')</li> <li>Midbrain tectum (means 'roof')</li> <li>Midbrain tegmentum (means 'covering')</li></ul>

Question 39

Q

Which of the three main divisions of the brain holds the ...

<ul> <li>Cerebral peduncles</li> <li>Midbrain Tectum</li> <li>Midbrain Tegmentum</li></ul>

?

Answer

A

Midbrain (Mesencephalon)

Question 40

Q

Which of the two sub-divisions of the Prosencephalon houses the...

<ul> <li>Cerebral hemispheres <ul> <li>Cerebral cortex</li> <li>Subcortical white matter</li> <li>Basal ganglia</li> <li>Basal forebrain nuclei</li> </ul> </li></ul>

?

Answer

A

Telencephalon

Question 41

Q

Which of the two sub-divisions of the Prosencephalon houses the...

<ul> <li>Thalamus</li> <li>Hypothalamus</li> <li>Epithalamus</li></ul>

?

Answer

A

Diencephalon

Question 42

Q

What is another name for the hindbrain?

Answer

A

Rhombencephalon ('Rom-ben-cefa-lon') [Means "Rhombus {the shape!} brain"]

Question 43

Q

What are the two sub-divisions of the Rhombencephalon (hindbrain)?

Answer

A

<ol> <li>Metencephalon  ("met-en-cefa-lon") [means 'meta{over}-brain']</li> <li>Myelencephalon ("My-elen-cefa-lon") [means 'marrow-brain]</li></ol>

Question 44

Q

Which of the three brain subdivisions houses the metencephalon? AND what components does the metencephalon contain?

Answer

A

Housed in the Rhombencephalon (hindbrain)

Contains:

<ul> <li>Pons </li> <li>Cerebellum</li></ul>

Question 45

Q

Which of the three brain subdivisions houses the myelencephalon? AND what components does the myelencephalon contain?

Answer

A

Housed in the Rhombencephalon (hindbrain)

Contains:

<ul> <li>Medulla</li></ul>

Question 46

Q

Which of the three main divisions of the brain AND which sub-division houses the....

<ul> <li>Pons </li> <li>Cerebellum</li></ul>

Answer

A

Rhombencephalon (hindbrain) --- Metencephalon

Question 47

Q

Which of the three main divisions of the brain AND which sub-division houses the....

<ul> <li>Medulla</li></ul>

Answer

A

Rhombencephalon (hindbrain) --- Myelencephalon

Question 48

Q

What is the choroid plexus [means 'resembling skin - network'] and what role does it play in regards to cerebrospinal fluid?

Answer

A

Vasular tufts lying within the ventricles.

Resposible for the production of cerebrospinal fluid.

Question 49

Q

How many choroid plexuses are there in the brain?

Answer

A

four, one in each of the four ventricles.

Question 50

Q

What role does the choroid plexus have in protection of the brain's CSF?

Answer

A

Tight gap junctions between the cells on the side facing the ventricle (apical surface) prevent the majority of substances from crossing the cell layer into the CSF; thus the CP acts as a blood–CSF barrier.

MORE INFORMATION (optional)

The CP consists of a layer of cuboidal epithelial cells surrounding a core of capillaries and loose connective tissue.  The CP epithelial layer is continuous with the ependymal cell layer that lines the ventricles, but unlike the ependyma, the epithelial layer has tight gap junctions between the cells on the side facing the ventricle (apical surface).

Question 51

Q

What foramen connects the left and right lateral ventricles

Answer

A

None!

Question 52

Q

What CSF pathway connects each lateral ventricle with the 3rd (mid) ventricle?

Answer

A

Inter-ventricular foramen

Question 53

Q

What CSF pathway connects the 3rd ventricle with the 4th ventricle?

Answer

A

Cerebral Aqueduct

Question 54

Q

What CSF pathways enables CSF movement from the 4th ventricle to the subarahnoice space?

Answer

A

<ol> <li>Lateral Apeture (right)</li> <li>Medial Apeture</li> <li>Lateral Apeture (left)</li></ol>

Question 55

Q

What CSF pathway connects the Subarachnoid space and Dural sinuses?

Answer

A

Arachnoid Villi

Question 56

Q

What is another name for the interventricular foramen?

Answer

A

Foramen of Monro

Question 57

Q

What is another name for the lateral apetures (CSF circulation system)

Answer

A

Foramina of Luschka

Question 58

Q

What is another name for the Medial aperture (CSF circulation system)?

Answer

A

Foramen of Magendie

Question 59

Q

Where is the CSF ultimately reabsorbed?

Answer

A

Once it leaves the ventricular system, CSF travels in the space between the arachnoid and pia and is ultimately reabsorbed into the venous system  (by Anarchnoid granulations)

MORE INFORMATION:

Ararchnoid grandulations are small protrusions of the arachnoid (the thin second layer covering the brain) through the dura mater (the thick outer layer). They protrude into the venous sinuses of the brain, and allow cerebrospinal fluid (CSF) to exit the sub-arachnoid space and enter the blood stream.

Largest granulations lie along the superior sagittal sinus, a large venous space running from front to back along the centre of the head (on the inside of the skull). They are, however, present along other dural sinuses as well. Smaller granulations are called villi, largecalcified ones are referred to as pacchionian bodies.

Question 60

Q

label the pathways of the CSF circulatory system (See image)

Answer

A

Question 61

Q

Label the major components of the CSF circulatory system

Answer

A

Question 62

Q

What three membranouse protective layers make up the meninges?

Answer

A

<ol> <li>Dura</li> <li>Arachnoid</li> <li>Pia</li></ol>

(Remember = PAD)

Question 63

Q

Above the midbrain....

Anterior = ? Posterior = ? Superior = ? Inferior = ?

Answer

A

Anterior = rostral Posterior = caudal Superior = dorsal Inferior = ventral

Question 64

Q

Below the midbrain:

Anterior = ? Posterior = ? Superior = ? Inferior = ?

Answer

A

Anterior = ventral Posterior = dorsal Superior = rostral Inferior = caudal

Answer 65

A

Oblique

Answer 66

A

Answer 67

A

<ol> <li>Nerve cells (AKA: neurons) - Basic units of signslling in the nervous system (though glia can contribute as well)</li> <li>Glia cells (AKA: Glia) - support cells</li></ol>

Answer 68

A

<ol> <li>Cell body</li> <li>Dendrites</li> <li>Axons</li> <li>Multipolar</li> <li>Dentrites</li> <li>Axons</li></ol>

Answer 69

A

<ul> <li>axon collaterals</li></ul>

Answer 70

A

bipolar

Answer 71

A

Bipolar cells are often sensory neurons, such as those involved in vision or olfaction.

Answer 72

A

synapses

Answer 73

A

<ol> <li>Axon terminal</li> <li>Dendrites </li></ol>

EXTRA INFORMATION, NOTE:

There are also axo-axonic and dendro-dendritic synapses, and some forms of communication can even occur in reverse, traveling from dendrites back to axons.

Answer 74

A

<ol> <li>Neurotransmitter</li> <li>Synaptic vesicles</li> <li>Presynaptic terminal</li> <li>Neurotransmitter receptors</li> <li>Postsynaptic</li></ol>

Answer 75

A

Electrical Synapses

Answer 76

A

Action potential occurs, lasting about 1 millisecond. They travel rapidly throughout the length of a neuron, along the cell membrane.

Classically, action potentials travel from the dendritic end of the neuron along its axon to reach presynaptic terminals, where communication can occur with the next neuron

Action potentials trigger release of neurotransmitter molecules from synaptic vesicles, allowing chemical communication with the postsynaptic cell (see

Answer 77

A

Axon Insulation comprised of specialized flial cells that form a lipid 'myelin sheath', thereby speeding the rate of action potential conduction.

Answer 78

A

Myelin sheaths

Answer 79

A

Ogliodendrocytes

Answer 80

A

Schwann cells

Answer 81

A

Voltage-gated ion channels are concentrated in short, exposed segments of the axon.

Answer 82

A

nodes of Ranvier

Answer 83

A

Salatory conduction

Answer 84

A

<ol> <li>One is to mediate rapid communication between neurons through fast excitatory or inhibitory electrical events known as "Excitatory postsynaptic potentials (EPSPs)" and "Inhibitory postsynaptic potentials (IPSP) </li> <li>neuromodulation - occuring over a slower time scale, includes a broad range of cellular mechanisms.</li></ol>

Answer 85

A

"Excitatory PostSynaptic Potentials (EPSPs)" and "Inhibitory PostSynaptic Potentials (IPSP)"

Fast EPSPs and IPSPs occur on the timescale of tens of milliseconds and rapidly move the membrane voltage of the postsynaptic neuron between states more or less likely to fire an action potential.

Answer 86

A

Generally occurring over slower time scales. Neuromodulation includes a broad range of cellular mechanisms involving signaling cascades that regulate synaptic transmission, neuronal growth, and other functions. Neuromodulation can either facilitate or inhibit the subsequent signaling properties of the neuron.

Answer 87

A

Glutamate

GABA (Gamma, AminoButyric Acid)

Answer 88

A

<ul> <li>Fascicle</li> <li>Lemniscus</li> <li>Bundle</li> <li>Tract</li></ul>

Answer 89

A

Commissure

Answer 90

A

<ol> <li>Peripheral nerves (or simply 'nerves')</li> <li>Ganglia</li></ol>

Answer 91

A

<ol> <li>afferent (think 'arrive')</li> <li>efferent (think 'exit')</li></ol>

EXTRA INFORMATION:

Thus, peripheral nerves convey afferent sensory information about the environment to the CNS and carry efferent signals for motor activity from the CNS to the periphery

Answer 92

A

<ol> <li>Olfactory nerve</li> <li>Optic Nerve</li> <li>Oculomotor nerve</li> <li>Trochlear nerve</li> <li>Trigeminal nerve</li> <li>Abducens nerve</li> <li>Facial Nerve</li> <li>Vestibulocochlear nerve</li> <li>Glossopharyngeal nerve</li> <li>Vagus nerve</li> <li>Hypoglossal nerve</li></ol>

(HOTFOOT GAAVV)

Answer 93

A

The insular cortex lies buried within the depths of the sylvian fissure. the insular is covered by a lip of frontal cortex anteriorly and parietal cortex posteriorly, called the frontal operculum and parietal operculum respectively. (operculum means 'covering' or 'lid in latin)

Answer 94

A

interhemispheric fissure, also known as the sagittal or longitudinal fissure

Answer 95

A

Insular cortex

Answer 96

A

Corpus Callosum

Answer 97

A

precentral gyrus

Answer 98

A

rostrum, genu, body, and splenium

Answer 99

A

1 rostrum;

2 genu;

3 rostral body,

4 anterior mid body;

5 posterior mid body;

6 isthmus;

7 splenium;

Typically 3-5  called the 'body'

Answer 100

A

Surrounds the corpus callosum, running from the paraterminal gyrus anteriorly to the isthmus posteriorly

Answer 101

A

Cingulate Gyrus

Answer 102

A

Central Sulcus, because it reaches the superior surface of the brain just posterior to the central sulcus line (i.e., it is the sulcus behind the realtively shallow central sulcus!)

Answer 103

A

This is done by demonstrating that a lesion to brain structure A disrupts function X but not function Y. Such a demonstration allows one to infer that function X and function Y are independent of each other in some way.

Answer 104

A

This is the demonstration that two experimental manipulations each have different effects on two dependent variables; if one manipulation affects the first variable and not the second, the other manipulation affects the second variable and not the first.[3] If one can demonstrate that a lesion in brain structure A impairs function X but not Y, and further demonstrate that a lesion to brain structure B impairs function Y but spares function X, one can make more specific inferences about brain function and function localization.

Answer 105

A

We use single case studies because aggregate data destroys the individual variation which reflects damage for that person.

Answer 106

A

is the concept that the mind has some internal architecture, the mind consists of  informationally encapsulated systems that process distinct and limited forms of sensory, cognitive or affective information (Fodor, 1983)

Answer 107

A

The downfall of using autopsy to establish correlations between brain anatomy and behaviour is that a lot can happen between the time of injury and autopsy  including dementia or neuroplasticity, making it hard to tell what has caused something.

Answer 108

A

<ul> <li>Wada test </li> <li>Angiogram</li></ul>

Either enable visualisation of blood supply or use the blood supply to deliver drugs which temporarily disable part of the brain.

Answer 109

A

A barbiturate is injected into one half of the brain at a time to tell where specific functions are located e.g. memory and language. This is often done before epilepsy surgery.

Answer 110

A

Angiography is a minimally invasive medical test that uses x-rays and an iodine-containing contrast material to produce pictures of blood vessels in the brain.

In cerebral angiography, a thin plastic tube called a catheter is inserted into an artery in the leg or arm through a small incision in the skin. Using x-ray guidance, the catheter is navigated to the area being examined. Once there, contrast material is injected through the tube and images are captured using ionizing radiation (x-rays).

Areas with more blood supply are normally more active.

EXTRA INFORMATION:

Cerebral angiography is also called intra-arterial digital subtraction angiography (IADSA). This phrase refers to acquiring the images electronically, rather than with x-ray film. The images are electronically manipulated so that the overlying bone of the skull, normally obscuring the vessels, is removed from the image resulting in the remaining vessels being clearly seen.

Answer 111

A

same technology as x-ray generally CT (now preferred over older techniques such as skull-xray and air encephalography). An xray source is moved around the head. Using thin xray beams, multiple imaging slices (2mm to 13mm thick) are taken of the patients head. These images are taken at a 20-degree angle to avoid distorion causes by the low (Air) and high (bone) densities in the sinus region and also to protect the eyes. Requires a large apparatus, xray tube, that can rotate 360degrees.

More sensitive than traditional xray detectors. detecting difference of 10-15% in the density of soft tissue (compared to variations of 1% in soft tissues for CT ) A computer inteprets the data, generates a picture of the brain that can be in any orientation (sagittal, horizontal, or coronal). Forms a 3d structure based on data froma  2d sources - similar to examining any 3d structure from many different angles and then drawing it from a different perspective.

Answer 112

A

Magnetic Resonance Imaging,

Based on the principle that different cells have a different water content and hydrogen ions. Once the alignment of these ions has been altered by the magnet, a radio frequency pulse is administered and they will spin back to their normal alignment and this spin can be read. This provides amazingly detailed images in all planes. This is normally considered an unpleasant process, especially if you’re claustrophobic and can be quite loud.

Answer 113

A

Uses MRI data to identify structural brain differences.

e.g., The cortex of people taught to juggle changes especially in the visual cortex (V5) and the intraparietal sulcus and then changes back when they stop juggling.

In another study, changes were observed using Voxel Based Morphometry in the grey matter of the posterior parietal cortex and the hippocampus in medical students as they were studying for exams, Even after studying had ceased for 3 months, the hippocampus continued to grow. This paper became known as practice makes cortex.

Answer 114

A

fMRI - Functional Magnetic Resonance Imaging

PET - Phositron Emission Tomography

SPECT - Single-photon Emission Computer Tomography

Answer 115

A

Functional Magentic Resonance Imaging - uses oxygenated blood to tell which region of interest (ROI) is active during particular tasks. This is done by comparing the flow of oxygenated blood and deoxygenated haemoglobin when at rest compared to when performing a task. The oxygenated and deoxygenated blood has different magnetic qualities. With this technique you see Blood Oxygen Level Dependent (BOLD) effects.

EXTRA INFORMATION:

fMRI scans have been able to show that areas of the brain normally associated with spoken language comprehension can adapt to non spoken forms of communication when they are used as a form of language. E.g. in the canary islands, sheep herders use whistles to communicate over distances that words would not cover, they show the same activation as language. In non-speakers of this language, whistling does not activate language comprehension areas.

Answer 116

A

Positron Emission Tomography and Single-Photon Emission Computed Tomography

work by attaching a radioactive isotope to water or glucose molecules so areas which do or do not have glucose and oxygen activity can be seen. This is a good technique for discovering functional lesions, areas of the brain which are not absorbing oxygen. As the radionucleid decays, the emitted positrons can be measured and the flow of oxygenated/glucose rich blood tracked. This can also be used to show the focus of seizures in epilepsy which shows up as areas of hypoperfusion.

Answer 117

A

Alzheimer’s disease which is characterised by extracellular β amyloid plaques which can be imaged with a substance known as 11C PIB (Pittsburgh Compound B) and intracellular tau-neurofibrillary tangles which can be imaged using 18F-FDDNP which also images Aβ plaques.

Amyloid plaque imaging uses a radioactive substance which sticks to either amyloid plaques or both plaques and neurofibrillary tangles and is a type of PET.

Answer 118

A

Diffusion Tensor Imaging (DTI) is a recent research area which looks at the integrity and directionality of white matter tracts. It measures the way water molecules move down white matter pathways and the direction of their movement.

EXTRA INFORMATION:

Two measurements are taken, Fractional Anisotropy (FA) which measures the direction of water movement and Mean Diffusivity (MD) which measures the magnitude of water movement. This technique is not yet used in clinical diagnoses but could be useful for closed head injuries where twisting and shearing of white matter is often a problem. Research in semantic dementia has shown white matter changes using DTI.

Answer 119

A

akin to EEG, measures brain activity via the magnetic fields generated by the electrical activity of neurons (as opposed to inferring from blood flow). Temporal specificity in MEG is in the order of tens not hundreds of milliseconds, but it can not be done with any metal in the body.

EXTRA INFORMATION:

Macquarie has the only child MEG machine in the southern hemisphere.

Answer 120

A

Transcrannial Magnetic stimulation - uses alternating magnetic fields to create a temporary lesion by disrupting cortical excitability.

Answer 121

A

In neurology, the left side of the brain is displayed on the left and the right side on the right but in radiology, the left and right dimension is flipped so the left will be displayed on the right and the right will be displayed on the left. You always need to check the labelling on scans.

Answer 122

A

Because they often have distinctive neuropathology

e.g.,

amyloid plaques, neurofibrillary tangles, lewy bodies, pick’s bodies or prion plaques. Within these lesions different types or mixes of misfolded proteins can be identified (e.g, tau, Ubiquitin, ά-Synuclein, TDP-43). Combined with different distribution within the fine structure (neurons vs glia, cytoplasm or nucleus of neuron) and regional distribution within the cns, this can help to distinguish diseases e.g. tau positive in alzheimers.

Answer 123

A

Neuroplasticity, also known as brain plasticity, is an umbrella term that encompasses both synaptic plasticity and non-synaptic plasticity—it refers to changes in neural pathways and synapses due to changes in behavior, environment, neural processes, thinking, emotions, as well as changes resulting from bodily injury.

EXTRA INFORMATION:

The brain increases in volume throughout childhood as new neurons are grown and new skills learnt. It then remains mostly steady till late adulthood when overall volume begins to decline. The brain exhibits more specific changes in response to experience as well. Rats raised in enriched environments had thicker cortices and larger (stronger) brains compared to rats raised in a normal environment. Similar experiments were also performed with dogs and birds. This led to the development of enrichment programs to counteract the effect of malnutrition in children or stave of dementia in the elderly. Plasticity has also been shown in the auditory cortex with musicians showing plasticity related changes in the auditory cortex. Mathematicians have increased grey matter density in the parietal cortex. Those of higher intelligence also show enhanced parahippocampal thickening over 20 years compared to normal and lower intelligence people as well as decreased superior frontal cortex thinning over 20 years.

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