The purpose of this lab is to familiarize you with structures of the human brain as visualized in virtual sections created with modern imaging techniques. As you go through this exercise, you should compare what you see with brain structures you saw during your work with the sheepís brain exercise.

Go to the Whole Brain Atlas site and use the features there to work through the exercises below.

1. Read the Neuroimaging Primer. Page 1 will help you familiarize yourself with brain imaging technology.

2. Label the standard planes of imaging on the diagram below.

3. Read "More Details of MR" to learn about image types and signal sources.

4. Read the page on Basic MR Imaging. How does increased tissue water (as might result from edema -- that is, swelling) appear in MR images? How does infarction (dead tissue caused by vascular blockage) appear in MR images? How does inflammation (caused by infection or hemorrhage) appear in T1 weighted MRI: bright or dark?

5. Using Page 2 of the Neuroimaging Primer, fill in the table below for normal tissue:
 

	MR1	MR2	x-ray CT
Dense bone
Air
Fat
Water
Brain

Why is the image of the brain given by MR1 called "anatomic?"
 
 

Fill in the table below for abnormal tissue:
 

	MR1	MR2	CT	Enhancement?*
Infarct
Bleed
Tumor
MS plaque
*Enhancement refers to whether the chemicals used to reveal leakages in the blood/brain barrier (gadolinium for MRI and iodine for CT) will show such leakage.

a. How can you know what level in the brain the current slice is from?
 
 

b. How can you tell what types of image of this brain are available and which one you are looking at?
 
 

c. What do the T-shaped "ticks" on the lower lines of the bottom graphic mean?
 
 

Note: SPECT T1 is PET with Thallium 201, a potassium analog compund which reveals blood/brain leakage. SPECT TC shows overall brain perfusion.

7. Go to the Atlas of Top 100 Brain Structures. Look up the following structures and fill in the table.
 

STRUCTURE	Slice #				Region of Brain (or lobe, if part of cerebrum)				Other structures at same level*
Superior temporal gyrus
Central sulcus
Precentral gyrus
Postcentral gyrus
Sylvian fissure
Basal ganglia (head of caudate)
Basal ganglia (putamen/globus pallidus)
Corpus callosum
Hippocampus
Angular gyrus
Fornix
Cingulate gyrus
Amygdala
Thalamus
Pineal gland
Superior colliculus
Inferior colliculus
Pons
Medulla
Cerebellar hemispheres
Optic chiasm
*Include only major structures -- for example, ones you observed in the sheep brain lab.

 

8. Return to the Whole Brain Atlas homepage and find the following pathological examples.

a. Acute stroke: speech arrest. Take the tour, read the clinical report (follow the link at the bottom of the page) and answer these questions: Where is the lesion? Which types of image show the lesion most effectively?
 
 
 
 
 
 

b. Acute stroke: fluent aphasia. Where is the lesion?
 
 
 
 

c. Glioma (a malignant growth of the supporting, non-neuronal cells of the brain). Take Tour 1 and read the clinical report. Where is the lesion? What type of imaging is used for Tour 1, and why?
 
 
 
 

Look at some of the slices with SPECT TC (this image shows blood flow perfusion), and SPECT T1 (shows blood/brain barrier leakage). What do the two images reveal about the effects of the tumor on the brain?
 
 

d. Alzheimer's Disease. Take Tour 1 and look at the SPECT TC and MRI images. What are some of the differences between this brain and a normal aged brain?
 
 

What part of the brain is most severely affected in this patient?
 
 

If you have time, you can also look at the Alzheimer's Visual Agnosia brain -- what differences do you notice between the two Alzheimer's brains?
 
 

e. Huntington's Disease. Read the clinical report. Compare this slice with the normal brain at the same level. What differences do you see? (Note: use the small image in the lower left and note the level of the yellow line on a prominent brain structure and match this on the normal brain. The slice numbers are not comparable between pictures!)