DTI/Virtual Lobotomy


Jump to: navigation, search

[edit] The Pro's Guide to Virtual Lobotomy

Performing virtual lobotmies is pretty simple. Insofar as background skills, you will need to have a solid working knowledge of Dave Akers CINCH program as well as mrDiffusion. Here are two links to other Wandell lab Wiki pages that detail the practice and use of those programs:

CINCH for Callosums: CINCH_Tech
mrDiffusion for Callosums: mrDTI_Callosums

Although these pages do not talk about lobotomy, they will help you learn how to use the software; they also contain links to other pages that detail the use of our software.

Now that you can use the software, do a little historical research on lobotomy by reading this brief article: History of Lobotomy
And also this totally mediocre wiki article on psychosurgery: Mediocre_Article, this article is mostly good for its references.

The basic idea to this project is to use DTI to recreate the effects of frontal lobotomy. DTI is a great tool for doing this because frontal lobotomy was aimed at severing white matter connections--not at removing or damaging cortex. We perform this estimation by drawing ROIs in the shape and plane of the cuts made during the psychosurgery. This beautiful poster perfectly portrays the brief story of the Stanford lobotomy project: CNS_Poster
Our project seeks to elucidate in more detail what happened to brains undergoing psychosurgery, both in terms of individual differences, and in terms of effect differences between the two procedures--transorbital and the Standard method (aka the Freeman/Watts method). Okay, so read your history, I figured out how they performed lobotomy by reading Freeman's book: 'Psychosurgery.' It is an interesting book, so check it out from the Lane Medical library if you want to get serious. So that's it for background, let's get into some details.

As we mentioned earlier, there were two main different kinds of lobotomy procedures that you will be recreating: 1. The Standard method and 2. the Transorbital method.

  1. ===Standard method===

The basic procedure for a Standard lobotomy was to enter the brain from the temple of the skull, at the plane of the coronal suture (run your thumb nail over your skull near your temples, feel that crack? That's the coronal suture). Bore holes were drilled in the side of the skull at points 3cm directly back from the corner of the eyelid and 6 cm superior from the ear canal. A surgical instrument was then passed through the brain from one of the burrholes to the other. This instrument was used to measure the diameter of the skull. The depth of insertion was determined from this measurement by dividing it in half and subtracting one centimeter. The blade was then inserted and swept upwards 45 degrees and then downwards, touching the sphenoidal ridge at the base of the brain cavity and then dragged along this level back and out the burrhole. All of this was performed in the plane of the coronal suture, which is just slightly tilted "back" when looking at a sagittal slice of brain.

  1. ===Transorbital method===

The Transorbital method is much simpler. The doctor (not necessarily a surgeon) entered the brain by inserting the instrument through the eyelid above the eye, and upwards, breaking the bone underneath the orbital lobes and inserting the instrument into the brain 7 cm deep and swinging the instrument in a 45 degree swing left to right, keeping in this plane of insertion, usually 45 degrees to the base of the skull.

[edit] Virtual lobotomy method

Open up the spreadsheet titled: Lobotomy Arc Radius, which is located on the White server. This is where you will keep track of, and store all your data concerning each individual's brain size, points of origin for the ROIs and the number of fibers severed in each method (which is not actually that important, but we keep track of it anyway). Also: every measurement and coordinate is done using AC/PC space, not Talairach. First, let's perform a Standard method lobotomy

  1. Open up your subjects dt6 file in mrDiffusion.
  2. Freeman often spoke of inserting the blade just anterior to the genu of the corpus callosum, this is the land mark we use. Position the X axis at a slice 3-5 mm anterior to the genu of the callosum. This will serve as our plane of incision for both ROIs.
  3. You will see a nice coronal T1. Look closely and you can see the boundary between the skull and the scalp, position the cursor at this point of the slice, at the 0 Z axis marker on the left side of the brain. Put the coordinates into the spreadsheet. Now do the same for the Right side of the brain. Once you enter the coords in the spreadsheet, it should calculate the proper diameter for the insertion--which is just the difference in Y values minus 10mm.
  4. Now we need to know the angle to go to the bottom of the skull. Keeping in the same coronal slice, put the cursor at the innermost corner of the left hemisphere where the orbital lobe dives toward the midsagittal plane. Note the coords of this point and input them into the spreadsheet, which will now give you the proper lower angle by calculating the sin of the little triangle you just drew. Do the same for both hemispheres.
  5. Put the cursor back at the point of insertion on the side of the skull--just paste in your coords from before. Go to your Matlab command line and type in: makeArcRoi.
  6. A little box will pop up and you should now input all your info from the spreadsheet into the box--this is radius, or depth, and lower angle. Press enter and the ROI will be drawn on your coronnal slice, do this for both hemispheres.
  7. Load all the fibers for each side (do this one side at a time) and do an "And with" condition with your new ROI, this will reveal all the fibers passing through your ROI and, we think, that were severed by the surgeon's knife.
Personal tools