Name: Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation (Video) | JoVE Journal
Uploaded: 2017-05-23T14:00:00.000+00:00
Duration: 16 min 23 s
Description: Explore fiber connections of the supplementary motor area using cadaveric dissection and advanced MR tractography. This protocol combines 3D documentation with diffusion imaging for neurosurgical planning.

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5 minutes

The data were provided in part by the Human Connectome Project, WU-Minn Consortium (Principal Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657), funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by the McDonnell Center for Systems Neuroscience at Washington University. Figures 2A and 2D were reproduced with permission from the Rhoton collection57 (http://rhoton.ineurodb.org/?page=21899).

The deceased are included here as a population, although deceased persons are not technically human subjects; human subjects are defined by 45 CF 46 as &#34;living human beings15,16.&#34;
1. Preparation of Specimens
<ol>
	<li>Examine 5 formalin-fixed brains (10 hemispheres) and 2 whole human heads.</li>
	<li>Fix the specimens in a 10% formalin solution for at least 2 months according to Klingler&#39;s method17.</li>
	<li>Freeze all specimens at -16 &#730;C for 2 weeks in accordance with Klinger&#39;s method17.</li>
	<li>Thaw the specimens under tap water.</li>
	<li>Perform an extended frontotemporal craniotomy on the cadaveric head to expose the brain.
	<ol>
		<li>Place the cadaveric head in a three-pin skull clamp (Material Table).</li>
		<li>Make a frontotemporal skin incision with a scalpel.</li>
		<li>Remove the skin and muscles using a scalpel, forceps, and scissors.</li>
		<li>Make one or more burr holes in the skull until the dura mater is reached; use a drill with a compact speed reducer and a 14 mm cranial perforator attachment at 79,000 rpm (Material Table).</li>
		<li>Cut the bone flap and open the skull using a 2 mm x 15.6 mm fluted router with a 2.1 mm pin-shaped burr attachment at a drill speed of 80,000 rpm (Material Table).</li>
	</ol>
	</li>
	<li>Remove the dura, arachnoid, and pia mater and dissect using a microdissector under a microscope at 6X to 40X magnification5,18
 (Material Table).</li>
</ol>
2. Fiber Dissection Technique
NOTE: Perform all dissections under 6X to 40X magnification on a surgical microscope.
<ol>
	<li>Perform the fiber dissections in a stepwise manner on each hemisphere, from lateral to medial and medial to lateral.
	<ol>
		<li>Decorticate the cerebral cortex using a panfield dissector (Material Table) and remove all frontal cortical tissues to expose the short association fiber tracts, which are U-fibers or intergyral fibers that interconnect neighboring gyri5,13.</li>
		<li>Remove the short association fibers with a panfield dissector and a surgical micro hook by gently trimming under the microscope (Material Table) to reach and expose the long association fibers, which interconnect distant areas in the same hemisphere.</li>
		<li>Go deep into the long association fibers to remove the superficial association fibers using a surgical micro hook and a panfield dissector; remove each fiber bundle under a microscope (Material Table) to expose the projection commissural fibers.</li>
		<li>View each of the connections of the SMA complex according to the topographical anatomy that was previously defined in the literature2,8,18,19,20,21.</li>
	</ol>
	</li>
	<li>Keep all specimens (whole heads and brains) that were used during the dissections in 10% formaldehyde solution (Material Table) between the dissection periods.</li>
</ol>
3. 3D Photography Technique
<ol>
	<li>Use a black color platform during the photography of the specimens.</li>
	<li>Follow a 3D photography technique22.
	<ol>
		<li>Place each specimen in a designed black color platform.</li>
		<li>Select a scene with a full-frontal view of the specimen and take one shot by focusing the camera on any point on the specimen close to the center point on the camera screen (instrument table). Use an 18- to 55-mm f/3.5-5.6 SLR lens or a 100 mm f/2.8L macro lens and set the aperture to F29, ISO 100.</li>
		<li>Rotate the camera slightly left until the right-most point on the camera screen is the same as the focusing point above. Slide the camera to the right until the middle point on the screen overlaps the original focusing point on the specimen. Focus the camera on this point and take another shot.</li>
		<li>Maintain the distance and axis of the camera to the specimen being photographed at constant values.</li>
	</ol>
	</li>
	<li>Create a 3D image by using a 3D image generator program (Material Table).
	<ol>
		<li>Open the 3D software program.</li>
		<li>Choose &#34;Open stereo images from File.&#34;</li>
		<li>Select the two images (left and right) and make sure the left image is in the left slot and the right image is in the right slot.</li>
		<li>Select the &#34;Half color anaglyph RL/2&#34; option and generate the anaglyph in jpeg format.</li>
	</ol>
	</li>
</ol>
4. DTI Technique
<ol>
	<li>Acquire pre-processed diffusion data utilizing the Human Connectome Project diffusion data23 by downloading it from the referenced website. 
	NOTE: The data is downloaded pre-processed and consisted of the following procedures: The diffusion data was acquired in normal volunteers using a modified 3 T MRI device (instrument table) utilizing a spin-echo echo planar imaging (EPI) sequence with multi-band image acceleration24,25,26,27,28. Relevant sequence parameters include: TR = 5,520 ms; TE = 89.5 ms; FOV = 210 x 180 mm; matrix = 168 x 144; slice thickness = 1.25 mm (voxel size 1.25 x 1.25 x 1.25 mm); multiband factor = 3; and b-values = 1,000 s/mm2(95 directions), 2,000 s/mm2(96 directions), and 3,000 s/mm2(97 directions). The data was then processed utilizing FreeSurfer29and FSL30; the process included eddy current correction, motion correction, b0 intensity normalization, susceptibility distortion correction, and gradient-nonlinearity correction28,31,32,33. Corresponding T1-weighted MP-RAGE images are also included in the download package. Procedures are documented in the Human Connectome Project procedures manual23.</li>
	<li>Post-process the diffusion data using Diffusion Spectrum Imaging (DSI) Studio34to generate an estimated voxel-wise diffusion orientation distribution function (ODF) employing a generalized q-sampling imaging (GQI) algorithm35.
	<ol>
		<li>Load the downloaded dataset into the software by selecting &#34;STEP1: Open source images&#34; and selecting the data.nii.gz file.</li>
		<li>Select the &#34;STEP2: Reconstruction&#34; button. After verifying the brain mask, proceed to &#34;Step 2&#34; and select &#34;GQI&#34; as the reconstruction method. Select &#34;r^2 weighting&#34; with a &#34;length ratio&#34; of &#34;1.0.&#34; Leave the remaining selections as the default.</li>
		<li>Select &#34;Run reconstruction.&#34;</li>
	</ol>
	</li>
	<li>Place appropriate seeds for regions-of-interest to streamline fiber-tracking.
	<ol>
		<li>In the &#34;Region Window,&#34; click the &#34;Atlas&#34; button to place seeds for the superior longitudinal fasciculus (SLF) I. Select &#34;Brodmann&#34; and add &#34;Region 6&#34; and &#34;Region 7.&#34; In the region window, set the &#34;Region 6&#34; type to &#34;seed&#34; and the &#34;Region 7&#34; type to &#34;region-of-inclusions&#34; (ROI).
		<ol>
			<li>Select &#34;New Region&#34; in the region window and manually draw an ROI in the most posterior aspect of the superior frontal gyrus in the coronal plane. Perform fiber tracking as described in step 4.4.</li>
		</ol>
		</li>
		<li>Place seeds for SLF II in similar fashion by using &#34;New Region&#34; in the region window and drawing the &#34;seed&#34; region in the posterior aspect of the middle frontal gyrus white matter in the coronal plane. Choose an ROI using &#34;Atlas&#34; (as in step 4.3.1) and Brodmann regions 9, 10, 46, 39, and 19. Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for SLF III with a &#34;seed&#34; region, using &#34;Atlas&#34; (as in step 4.3.1) in the region window and choosing &#34;Region 40&#34; of the Brodmann atlas and the ROI from &#34;Atlas&#8230;&#34; in &#34;Region 40&#34; and &#34;Region 44.&#34; Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for callosal fibers using &#34;New Region&#34; in the region window and drawing a &#34;seed&#34; in the sagittal plane encompassing the corpus callosum. Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for cingulate fibers using &#34;New Region&#34; in the region window and drawing a &#34;seed&#34; region in the mid-cingulate gyrus on the coronal view. Use &#34;New Region&#34; to draw two ROIs, one in the more anterior cingulate and one in the posterior cingulate gyrus under coronal view. Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for claustrocortical fibers using &#34;New Region&#34; in the region window and drawing a &#34;seed&#34; in the claustrum with an ROI in the corona radiata using the &#34;Atlas&#8230;&#34; function. Select the atlas as &#34;JHU-WhiteMatter-labels-1mm.&#34;
		<ol>
			<li>Select and add the &#34;Anterior_corona_radiata&#34;, &#34;Posterior_corona_radiata,&#34; and &#34;Superior_corona_radiata&#34;. Draw a region-of-avoidance for all fibers passing through a plane inferior to the level of the claustrum in the axial plane using &#34;New Region&#34; in the region window. Perform fiber tracking as described in step 4.4.</li>
		</ol>
		</li>
		<li>Place seeds for the corticospinal tract using a &#34;seed&#34; from the &#34;Atlas...&#34; function in the region window; select &#34;JHU-WhiteMatter-labels-1mm&#34; and add the &#34;Corticospinal_tract&#34; region. Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for the frontal aslant tract (FAT) using a &#34;seed&#34; region from the &#34;Atlas...&#34; function in the region window and selecting the Brodmann atlas and &#34;Region 6&#34; ROIs in &#34;Region 44&#34; and &#34;Region 45.&#34; Perform fiber tracking as described in step 4.4.</li>
		<li>Place seeds for the frontostriatal tract (FST) with a &#34;seed&#34; in &#34;Region 6&#34; using the &#34;Atlas...&#34; function. Insert new regions in the &#34;caudate,&#34; &#34;putamen,&#34; and &#34;globus pallidus&#34; from the &#34;HarvardOxfordSub&#34; atlas and set the type in the region window to &#34;end.&#34; 
		&#8203;NOTE: Fiber tracking for FST will be performed by selecting the Region 6 seed and only one of the subcortical seeds per tracking session (i.e., region 6 and the caudate, followed by region 6 and the putamen, and lastly region 6 and the globus pallidus).
		<ol>
			<li>Perform fiber tracking as described in step 4.4 for each combination.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Perform fiber tracking for each of the above combinations.
	<ol>
		<li>In the &#34;Options&#34; window, set the tracking parameters as: termination index of qa of 0.08, angular threshold of 75, step size of 0.675, smoothing of 0.2, minimum length of 20 mm, and maximum length of 200 mm. Select the seed orientation as &#34;All,&#34; the seed position as &#34;Subvoxel,&#34; and randomize seeding as &#34;On.&#34; Use trilinear direction interpolation with a streamline (Euler) tracking algorithm. For each combination of regions above, choose &#34;Run tracking&#34; in the &#34;Fiber Tracts&#34; window. 
		NOTE: Due to the randomized nature of the tracking, clear &#34;false fibers&#34; are identified and selectively removed, with regions-of-avoidance drawn by hand as a &#34;New Region.&#34;</li>
	</ol>
	</li>
	<li>Affine register the brain-extracted T1-weighted 3D MP-RAGE scan provided in the Human Connectome Project data set to the diffusion data using the &#34;Slices -&#62; Insert T1/T2 Images&#34; function of DSI-Studio. Generate a surface rendering of the brain by selecting &#34;Slices -&#62; Add Isosurface.&#34; Use a &#34;threshold&#34; of 665.</li>
</ol>

The authors declare no competing financial interests and no sources of funding and support, including any for equipment and medications.

The Importance of and Study Techniques for the White Matter Pathways
The cerebral cortex is accepted as a principal neural structure associated with 2.5 million years of human life. Approximately 20 billion neurons have separated into various parts based upon morphological and cellular specification40. The architecture of each of these cortical parts has been functionally sub-grouped, such as sensorimotor sense and movement, emotional experience, and complex reasoning. It ...

Among the 14 frontal areas delineated by Brodmann, the premotor and prefrontal area that lies in front of the precentral motor cortex has long been considered as a silent module, despite the fact that the frontal lobe plays an important role in cognition, behavior, learning, and speech processing. In addition to the supplementary motor area (SMA) complex, consisting of the pre-SMA and the SMA proper (Brodmann Area; BA 6) that extends medially, the pre-motor/frontal module includes the dorsolateral prefrontal (BA 46, 8, and 9), frontopolar (BA 10), and ventrolateral prefrontal (BA 47) cortices, as well as part of the orbitofrontal cortex (BA 11) on the lateral surface of the brain1,2.
The SMA complex is a significant anatomical area that is defined by its functions and its connections. The resection and damage of this region causes significant clinical deficits known as the SMA syndrome. The SMA syndrome is an important clinical condition that is particularly observed in frontal glioma cases that contain the SMA complex3. The SMA complex has connections with the limbic system, basal ganglia, cerebellum, thalamus, contralateral SMA, superior parietal lobe, and portions of the frontal lobes via fiber tracts. The clinical effect of damage to these white matter connections may be more severe than to the cortex. This is because the consequences of injury to the cortex can be ameliorated over time due to high cortical plasticity 4,5,6,7,8,9,10,11,12,. Therefore, the SMA regional anatomy and the white matter pathways should be deeply understood, in particular for glioma surgery.
A comprehensive understanding of the anatomy of white matter pathways is important for the wide-spectrum treatment of neurosurgical lesions. Recent studies of the three-dimensional documentation of the anatomical results that were obtained in microsurgery were used to gain a better understanding of the topographical anatomy and the interrelationship of brain white matter pathways13,14. Therefore, the purpose of this study was to examine the white matter connections of the SMA complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance imaging (MRI) tractography and to explain all the methods and principles of both techniques and their detailed documentation.
Planning and Strategy of Study
Prior to performing the experiments, a literature search on the basic principles of fiber dissections, the procedures that need to be applied to specimens before and during dissections, and all connections between SMA regions that have been revealed with dissection and DTI was conducted. The previous studies on the anatomical localization and separation of pre-SMA and SMA-proper regions and on the topographic anatomy of their connections were reviewed.

<table><tbody><tr><td>%4 Paraformaldehyde Solution</td><td>AFFYMETRIX, Inc.</td><td>2046C208</td><td>used to fixation</td></tr><tr><td>Freezer</td><td>INSIGNA</td><td>NS-CZ70WH6</td><td>used to freez</td></tr><tr><td>Panfield Dissector</td><td>AESCULAP</td><td>FD305</td><td>used to dissection</td></tr><tr><td>Surgical Micro Scissor</td><td>W. Lorenz</td><td>04-4238</td><td>used to miscrodissection</td></tr><tr><td>Surgical Micro Hook</td><td>V. Mueller</td><td>NL3785-009</td><td>used to miscrodissection</td></tr><tr><td>MICRO VESSEL STRETCHER/DILATOR</td><td>W. Lorenz</td><td>04-4324</td><td>used to miscrodissection</td></tr><tr><td>Emax2 SC 2000 Electric Console</td><td>Anspach Companies</td><td>SC2102</td><td>used to craniatomy</td></tr><tr><td>Drill Set</td><td>Anspach Companies</td><td>NS-CZ70WH6</td><td>used to craniatomy</td></tr><tr><td>20-1000 operating microscope</td><td>Moeller-Wedel,Germany</td><td>FS 4-20</td><td>used to miscrodissection</td></tr><tr><td>Canon EOS 550D 18 MP CMOS APS-C Digital SLR Camera</td><td>Canon Inc.</td><td>DS126271</td><td>used to take photos</td></tr><tr><td>EF 100 mm f/2.8L IS USM Macro Lens</td><td>Canon Inc.</td><td>4657A006</td><td>used to take photos</td></tr><tr><td>MR-14EX II Macro Ring Lite (Flash)</td><td>Canon Inc.</td><td>9389B002</td><td>used to take photos</td></tr><tr><td>Tripod</td><td>Lino Manfrotto</td><td>322RC2</td><td>used to take photos</td></tr><tr><td>MAYFIELD Infinity Skull Clamp</td><td>Integra Inc.</td><td>A0077</td><td>used to fix the head</td></tr><tr><td>Modified Skrya 3T &quot;Connectome&quot; Scanner</td><td>Siemens Company, Inc.</td><td>A911IM-MR-15773-P1-4A00</td><td>used to scan DTI</td></tr><tr><td>XstereO Player</td><td>Yury Golubinsky</td><td>Version 3.6(22)</td><td>used to create anaglyphs</td></tr><tr><td>EF-S 18-55mm f/3.5-5.6 IS II SLR Lens</td><td>Canon Inc.</td><td>2042B002</td><td>used to take photos</td></tr><tr><td>Scalpel</td><td>6B INVENT</td><td>7-104-L</td><td>used to make incision</td></tr><tr><td>Compact Speed Reducer</td><td>Anspach Companies</td><td>CSR60</td><td>used to make burr hole</td></tr><tr><td>14 mm Cranial Perforator</td><td>Anspach Companies</td><td>CPERF-14-11-3F</td><td>used to make burr hole</td></tr><tr><td>2 mm x 15.6 mm Fluted Router</td><td>Anspach Companies</td><td>A-CRN-M</td><td>used to make craniotomy</td></tr><tr><td>2.1 mm Pin-shaped Burrs</td><td>Anspach Companies</td><td>03.000.130S</td><td>used to make craniotomy</td></tr></tbody></table>

fiber connections of the supplementary motor area revisited: methodology of fiber dissection, dti, and three dimensional documentation

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance (MR) tractography. The protocol will also describe the procedure for a white matter dissection of a human brain, diffusion tensor tractography imaging, and three-dimensional documentation. The fiber dissections on human brains and the 3D documentation were performed at the University of Minnesota, Microsurgery and Neuroanatomy Laboratory, Department of Neurosurgery. Five postmortem human brain specimens and two whole heads were prepared in accordance with Klingler's method. Brain hemispheres were dissected step by step from lateral to medial and medial to lateral under an operating microscope, and 3D images were captured at every stage. All dissection results were supported by diffusion tensor imaging. Investigations on the connections in line with Meynert's fiber tract classification, including association fibers (short, superior longitudinal fasciculus I and frontal aslant tracts), projection fibers (corticospinal, claustrocortical, cingulum, and frontostriatal tracts), and commissural fibers (callosal fibers) were also conducted.

The SMA complex is situated in the posterior part of the superior frontal gyrus. The borders of the SMA complex are the precentral sulcus posteriorly, the superior frontal sulcus inferior-laterally, and the cingulate sulcus inferior-medially18. The SMA complex consists of two parts: the pre-SMA anteriorly and the SMA proper posteriorly18. There are differences in terms of white matter connections and function between these two parts<sup clas...

The purpose of this study is to show each step of the fiber dissection technique on human cadaveric brains, the 3D documentation of these dissections, and the diffusion tensor imaging of the anatomically dissected fiber pathways.

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex ...

The overall goal of this project is to explore the fiber connections of the supplementary motor complex in humans using a combination of in vivo fiber tracking via MRI combined with cadaveric fiber microdissection. This method can help answer key questions in the field leading to white matter anatomy of the human brain, such as how microdissection and DTI technique are done and how 3D photography and documentation of these studies are performed. The main advantage of this technique is to understand the anatomy of the white matter pathways of supplementary motor area comprehensively.The implications of this technique extending towards therapy and brain tumor surgery since the in vivo fiber tracking techniques can be applied in the preoperative setting to minimize postoperative complications. There, this method can provide insight into the fiber connections of the supplementary motor area can also be applied to virtually any other brain region to assess the fiber track connections. Generally, individuals new to MRI diffusion fiber tracking will struggle because they more widely-adopted diffusion tensor imaging has significant limitations in the ability to model crossing fibers amongst other limitations.Therefore, we adopted the method of generalized Q-sampling modeling to allow more accurate fiber tracking. I will be demonstrating the procedure with Dr.Cevik, an neuroanatomy fellow from our laboratory. To begin, prepare formalin-fixed brains according to Klingler's method.Place the cadaveric head in a three-pin skull clamp and use a scalpul to make a frontotemporal skin incision. Then, use a scalpel, forceps, and scissors to remove the skin and muscles from the head. Next, use a drill with a compact speed reducer and a 14 millimeter cranial perforator attachment to make one or more burr holes in the skull until the dura mater is reached.Then, use a router with a burr attachment to cut the bone flap. Open the skull and expose the brain. Once exposed, remove the dura arachnoid and pia mater and place the tissue under a microscope at six to 40 times magnification.Use a Penfield Dissector to decorticate the cerebral cortex and remove all frontocortical tissues to expose the short association fiber tracks. These can be identified as U-fibers, or intergyral fibers that interconnect neighboring gyri. With the assistance of a micro hook, gently remove the short association fibers to reach and expose the long association fibers, which interconnect distant areas in the same hemisphere.White matter pathways are composed of myelinated fibers and examined in three main categories. Associated fibers are wide connections between the different cortical regions in the same hemisphere;commissural fibers provide connection between both hemispheres, and projection fibers provide connection between the cortex and the cargo part of the brain and the spinal cord. Then, use the surgical micro hook and Penfield Dissector to go deep into the long association fibers and remove the superficial association fibers.Remove each fiber bundle to expose the projection commissural fibers. Start by placing the specimen in a designed black color platform. Select a scene with a full frontal view of the specimen.And take one shot by focusing the camera on any point of the specimen close to the center point on the camera screen. Rotate the camera slightly left until the right-most point on the camera screen is the same as the focusing point above. Then slide the camera to the right until the middle point on the screen overlaps the original focusing point on the specimen.Focus the camera on this point and take another shot. In the 3D software program, open the stereo images so that the left image is in the left slot and the right image is in the right slot. then select the Half Color Anaglyph RL2 option and generate the anaglyph in JPEG format.Start by downloading pre-process diffusion data from the Human Connectome Project website. And post-process it using Diffusion Spectrum Imaging Studio. To accomplish this, load the dataset into the software by first selecting Step1 Open Source Images, and then selecting the data nii.gz file. Next, select the Step2 Reconstruction button. After verifying the brain map, select generalized Q-sampling imaging as the reconstruction method.Also, select r-squared weighting with a length ratio of 1.0. Leave the remaining the selections as default, and then select Run Reconstruction. Place seeds for the cortical spinal tract using a seed from the Atlas function in the Region window.Select JHU White Matter labels 1 millimeter, and the cortical spinal tract region. Then, perform fiber tracking by first going to the Options window and setting the tracking parameters as shows here. Select the seed orientation as All, the see position as Subvoxel, and randomized seeding as On.Also, use Trilinear direction interpolation with a streamline tracking algorithm and choose Run Tracking in the fiber tract's window.Due to the randomized nature of tracking, you may find so-called false fibers, or fibers that are not of interest. These can be cleared by using regions of avoidance that can be drawn by hand as a new region. In the Region window, click the Atlas button to place seeds for the superior longitudinal fasciculus 1.Select FreeSurferDKT, left_superior_frontal and left_precuneus. Then in the Region window, set the left_precuneus type to Seed, and the left_superior_frontal type to ROI. Next, in the Region window, select New Region, and manually draw a region of inclusion in the most posterior aspect of the superior frontal gyrus in the coronal plane.Then, perform fiber tracking as previously described. next, perform the same process for the superior longitudinal fasciculus two. First, use New Region from the Region window and draw the seed region in the posterior aspect of the middle front gyrus white matter in the coronal plane.Then, choose a region of inclusion using Atlas a FreeSurferDKT regions, left_rostral_middle_frontal, and left_caudal_middle_frontal. And FreeSurferSeg Atlas region ctx_lh_G_pariet_inf-Angular. Complete this process by performing fiber tracking as previously described.For fiber tracking of the superior longitudinal fasciculus 3, place seeds with a seed region using Atlas. Choose ctx_lh_G_pariet_inf-Supermar of the FreeSurferSeg atlas. Then, select the region of inclusion from Atlas in ctx_lh_G_front_inf-Opercular from the FreeSurferSeg atlas.Complete this process by performing fiber tracking as previously described. For the callossal fibers, place seeds using a new region and draw a seed in the sagittal plane encompassing the corpus callosum. Complete this process by performing fiber tracking as previously described after increasing Terminate if to 900 tracts.For cingulate fibers, place seeds using a new region and draw a seed region the mid cingulate gyrus on the coronal view. Use New Region to draw a region of inclusion in the posterior cingulate gyrus under coronal view. Complete this process by performing fiber tracking as previously described.Next, place seeds for claustrocortical fibers using the Atlas function to place a region in Claustrum under the talairach atlas. Next, select Atlas and add regions left_superior_parietal and left_superior_frontal from the FreeSurferDKT atlas. In the Region window, set Claustrum to End and the other two regions to Seed.Based on the accuracy of the registration, the regions may need some modification in position, particularly the claustrum due to the small size of structure. These are found by right-clicking the region in the Region window and selecting the change in position from the Move Region options. Perform fiber tracking as in previous steps.Place seeds for the frontal aslant tract by first selecting the Atlas function and selecting the left_pars_opercularis from the FreeSurferDKT atlas, and then another region using the Atlas function and selecting Supp_Motor_Area_L from the aal atlas. Next, set left_pars_opercularis to End in the Region window, and the set Supp_Motor_Area_L to Seed. For the frontal striatal tract, again, select the Atlas function and then Supp_Motor_Area_L from the aal atlas.Next, choose the Atlas function and then select Striatum_L from the ATAG_basal_ganglia atlas. In the Region window, set Striatum_L to End, and Supp_Motor_Area_L to Seed. Then, generate a surface rendering of the brain by selecting Slices and Add Isosurface.The threshold value may vary based on the dataset and may have to be adjusted until the results are satisfactory. It is critical to gain a better understanding of topographical anatomy, particularly through 3D anatomical studies and to use clinical features of these connections to plan surgery in order to prevent permanent damage. The supplementary motor area complex consists of two parts:the Pre-SMA anteriorly, shown here in purple, and the SMA-Proper posteriorly, shown in green.The cortical and subcortical connections of these two parts are shown here, using fiber dissection and DTI techniques. After decortication, the short association fibers, called U-fibers, are exposed. U-fibers connect neighboring gyri to each other, such as the pre-SMA to the SMA-Proper, and the SMA-Proper to the motor cortex.In this lateral view, the connections made by the SLF 1, 2, and 3 can be seen. After removing a part of the SLF 2 at the corona level, the FAT was exposed. FAT fibers travel obliquely from the SMA region to the inferior frontal gyri and become superficial in the Pars Opercularis.Here, the exposed borderline of the claustrocortical fiber distribution on the cortical area can be seen. This is between the anterior part of the pre-SMA, and the posterior part of the parietal lobe. The DTI technique is powerful for visualizing the location of fibers throughout the brain.The images shown here highlight the position of the SLF fibers, as well as describe the relationship of the FAT and FST. In addition, the technique can be used to show the position of callosal fibers, cingular fibers, and claustrocortical fibers. While attempting the MRI tracking procedure, it's important to remember that data quality is critical to success.In this project, we utilize high quality data from the Human Connectome Project database. We routinely replicate such results on our 3D clinical scanners, but it's important to remember that acquisition of such high quality data may require lengthy MRI acquisitions, depending on the MRI scanner available. An understanding of the fiber tract connections of the supplementary motor area complex is essential for planning the frontal lobe surgery.After watching this video, you should have a good understanding of microsurgical entangled with anatomy of the supplemental motor area complex.

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Research

JoVE Journal

Neuroscience

We describe a novel approach for simultaneous analysis of brain function and structure using magnetic resonance imaging (MRI). We assess brain structure with high-resolution diffusion-weighted imaging and white-matter fiber tractography. Unlike standard structural MRI, these techniques allow us to directly relate anatomical connectivity to functional properties of brain networks.

Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging

Diffusion tensor imaging (DTI) basically serves as an MRI-based tool to identify in vivo the microstructure of the brain and pathological processes due to neurological disorders within the cerebral white matter. DTI-based analyses allow for application to brain diseases both at the group level and in single subject data.

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Diffusion tensor imaging (DTI) was performed to try to depict the major parts of the visual pathway. The goal was to use an FDA approved standard commercial workstation which could be used for everyday routine in order to try to reduce postoperative damage of the visual pathway in the patients.

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

In order to study brain reorganization under pathological conditions we used miniosmotic pumps for direct protein delivery into the brain circumventing the blood brain barrier. Tract tracers are then injected to study alterations in brain connectivity under the influence of the protein.

Implantation of Miniosmotic Pumps and Delivery of Tract Tracers to Study Brain Reorganization in Pathophysiological Conditions

This manuscript describes deterministic and probabilistic algorithms for white matter (WM) reconstruction, used to examine differences in optic radiation (OR) connectivity between albinism and controls. Although probabilistic tractography follows the true course of nerve fibers more closely, deterministic tractography was run to compare the reliability and reproducibility of both techniques.

Measuring Connectivity in the Primary Visual Pathway in Human Albinism Using Diffusion Tensor Imaging and Tractography

The goal of this project is to develop an interactive, patient-specific modeling pipeline to simulate the effects of deep brain stimulation in near real-time and provide meaningful feedback as to how these devices influence neural activity in the brain.

Targeting Neuronal Fiber Tracts for Deep Brain Stimulation Therapy Using Interactive, Patient-Specific Models

Here, we present a protocol for the application of diffusion tensor imaging parameters to evaluate spinal cord compression.

Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression

Here, we describe a standardized protocol for motor mapping using nTMS combined with diffusion tensor imaging (DTI)-based reconstruction of the corticospinal tract (CST). The protocol is reproducible, clinically feasible, and readily integrable into routine clinical workflows, providing a robust and valuable framework for motor pathway assessment, neuroplasticity research, and rehabilitation planning.

A Standardized Protocol for Functional Motor Mapping Using Navigated Transcranial Magnetic Stimulation

The Giant Fiber System is a simple neuronal circuit of adult Drosophila melanogaster containing the largest neurons in the fly. We describe the protocol for monitoring synaptic transmission through this pathway by recording post synaptic potentials in dorsal longitudinal (DLM) and tergotrochanteral (TTM) muscles following direct stimulation of the Giant Fiber interneurons.

Electrophysiological Recordings from the Giant Fiber Pathway of D. melanogaster

An in vivo dissection of the adult Drosophila ventral nerve cord (VNC) is demonstrated. This particular dissection method causes little damage to the VNC allowing the subsequent labeling of the giant fiber neurons with fluorescent dye for high resolution imaging.

Whole Mount Preparation of the Adult Drosophila Ventral Nerve Cord for Giant Fiber Dye Injection

Explore fiber connections of the supplementary motor area using cadaveric dissection and advanced MR tractography. This protocol combines 3D documentation with diffusion imaging for neurosurgical planning.

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation (Video) | JoVE Journal

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

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