Name: exposure of the pig cns for histological analysis: a manual for decapitation, skull opening, and brain removal
Uploaded: 2017-04-13T14:00:00
Description: Watch this Scientific Journal Video about Exposure of the Pig CNS for Histological Analysis: A Manual for Decapitation, Skull Opening, and Brain Removal at JoVE.com

The authors acknowledge with gratitude the skillful assistance of Mrs. Trine W. Mikkelsen, Mrs. Lise M. Fitting, and the staff at P&#229;skeh&#248;jgaard. The Danish Medical Research Council, the Lundbeck Foundation, and the Novo Nordisk Foundation financially supported the study.

Animal anesthesia and euthanesia was performed in accordance with &#34;Principles of laboratory animal care&#34; (NIH publication No. 86-23, revised 1985) and approved by the Danish Council for Animal Research Ethics.
1. Instruments
<ol>
	<li>Collect the instruments presented in the video and listed in the Table of Materials.</li>
</ol>
2. Decapitation
NOTE: Anesthesia was induced by an intramuscular injection of 5 mL of mida...

<ol>
	<li>Lind, M. N., Moustgaard, A., Jelsing, J., Vajta, G., Cumming, P., Hansen, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+pigs+in+neuroscience:+Modeling+brain+disorders.">The use of pigs in neuroscience: Modeling brain disorders.</a> Neurosci Biobehav Rev. 31, 728-751 (2007).</li><li>Bjarkam, C. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuromodulation+in+a+minipig+model+of+Parkinson+disease.">Neuromodulation in a minipig model of Parkinson disease.</a> British J Neurosurg. 22 (Suppl. 1), S9-S12 (2008).</li><li>Bjarkam, C. R., Cancian, G., Glud, A. N., Ettrup, K. S., &#216;stergaard, L., S&#248;rensen, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MRI-guided+stereotaxic+targeting+in+pigs+based+on+a+stereotaxic+localizer+box+fitted+with+an+isocentric+frame+and+use+of+SurgiPlan+computer-planning+software.">MRI-guided stereotaxic targeting in pigs based on a stereotaxic localizer box fitted with an isocentric frame and use of SurgiPlan computer-planning software.</a> J Neurosci Methods. 183 (2), 119-126 (2009).</li><li>Sauleau, P., Lapouble, E., Val-Laillet, D., Malbert, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pig+model+in+brain+imaging+and+neurosurgery.">The pig model in brain imaging and neurosurgery.</a> Animal. 3 (8), 1138-1151 (2009).</li><li>Bjarkam, C. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safety+and+function+of+a+new+clinical+intracerebral+microinjection+instrument+for+stem+cells+and+therapeutics+examined+in+the+Göttingen+minipig.">Safety and function of a new clinical intracerebral microinjection instrument for stem cells and therapeutics examined in the Göttingen minipig.</a> Stereotact Funct Neurosurg. 88 (1), 56-63 (2010).</li><li>Fjord-Larsen, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+delivery+of+nerve+growth+factor+by+encapsulated+cell+biodelivery+in+the+minipig+basal+forebrain.">Long-term delivery of nerve growth factor by encapsulated cell biodelivery in the minipig basal forebrain.</a> Mol Therapy. 18 (12), 2164-2172 (2010).</li><li>S&#248;rensen, J. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+neuromodulation+treatments+in+a+large+animal+model+-+Do+neurosurgeons+dream+of+electric+pigs?.">Development of neuromodulation treatments in a large animal model - Do neurosurgeons dream of electric pigs?.</a> Prog Brain Res. 194, 97-103 (2011).</li><li>Dolezalova, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pig+models+of+neurodegenerative+disorders:+utilization+in+cell+replacement-based+preclinical+safety+and+efficacy+studies.">Pig models of neurodegenerative disorders: utilization in cell replacement-based preclinical safety and efficacy studies.</a> J Comp Neurol. 522 (12), 2784-2801 (2014).</li><li>Mikkelsen, M., Moller, A., Jensen, L. H., Pedersen, A., Harajehi, J. 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H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+DaNEX+study+of+embryonic+mesencephalic,+dopaminergic+tissue+grafted+to+a+minipig+model+of+Parkinson's+disease:+Preliminary+findings+of+effect+of+MPTP+poisoning+on+striatal+dopaminergic+markers.">The DaNEX study of embryonic mesencephalic, dopaminergic tissue grafted to a minipig model of Parkinson's disease: Preliminary findings of effect of MPTP poisoning on striatal dopaminergic markers.</a> Cell Transplant. 9 (2), 247-259 (2000).</li><li>Dalmose, A., Bjarkam, C. R., S&#248;rensen, J. C., J&#248;rgensen, T. M., Djurhuus, J. 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H., Cumming, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pig+brain+stereotaxic+standard+space:+Mapping+of+cerebral+blood+flow+normative+values+and+effect+of+MPTP-lesioning.">Pig brain stereotaxic standard space: Mapping of cerebral blood flow normative values and effect of MPTP-lesioning.</a> Brain Res Bull. 66 (1), 17-29 (2005).</li><li>Glud, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+gene+transfer+in+the+minipig+CNS+using+stereotaxic+lentiviral+microinjections.">Direct gene transfer in the minipig CNS using stereotaxic lentiviral microinjections.</a> Acta Neurobiol Exp. 70 (3), 1-8 (2010).</li><li>Glud, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+MRI-guided+stereotaxic+viral+mediated+gene+transfer+of+alpha-synuclein+in+the+minipig+CNS.">Direct MRI-guided stereotaxic viral mediated gene transfer of alpha-synuclein in the minipig CNS.</a> Acta Neurobiol Exp. 71 (4), 508-518 (2011).</li><li>Ettrup, K. S., S&#248;rensen, J. C., Rodell, A., Alstrup, A. K. O., Bjarkam, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothalamic+deep+brain+stimulation+influences+autonomic+and+limbic+circuitry+involved+in+the+regulation+of+aggression+and+cardiocerebrovascular+control+in+the+minipig.">Hypothalamic deep brain stimulation influences autonomic and limbic circuitry involved in the regulation of aggression and cardiocerebrovascular control in the minipig.</a> Stereotact Funct Neurosurg. 90 (5), 281-291 (2012).</li><li>Nielsen, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+MPTP+intoxication+in+the+minipig+results+in+chronic+parkinsonian+deficits.">Continuous MPTP intoxication in the minipig results in chronic parkinsonian deficits.</a> Acta Neurobiol Exp. 76, 198-210 (2016).</li><li>Bjarkam, C. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+MRI-compatible+stereotaxic+localizer+box+enables+high-precision+stereotaxic+procedures+in+pigs.">A MRI-compatible stereotaxic localizer box enables high-precision stereotaxic procedures in pigs.</a> J Neurosci Methods. 139 (2), 293-298 (2004).</li><li>Bjarkam, C. R., Jorgensen, R. L., Jensen, K. N., Sunde, N. A. A., S&#248;rensen, J. C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deep+brain+stimulation+electrode+anchoring+using+BioGlue&#174;,+a+protective+electrode+covering,+and+a+titanium+microplate.">Deep brain stimulation electrode anchoring using BioGlue&#174;, a protective electrode covering, and a titanium microplate.</a> J Neurosci Methods. 168, 151-155 (2008).</li><li>Ettrup, K. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+Surgical+Techniques+in+the+Minipig:+Intubation,+Transurethral+Bladder+Catheterization,+Femoral+Vessel+Catheterization,+and+Transcardial+Perfusion.">Basic Surgical Techniques in the Minipig: Intubation, Transurethral Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion.</a> J Vis Exp. (52), e2652 (2011).</li><li>Ettrup, K. S., Torn&#248;e, J., S&#248;rensen, J. C., Bjarkam, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+surgical+device+for+minimally+invasive+implantation+of+experimental+deep+brain+stimulation+leads+in+large+research+animals.">A surgical device for minimally invasive implantation of experimental deep brain stimulation leads in large research animals.</a> J Neurosci Methods. 200 (1), 41-46 (2011).</li><li>Danielsen, E. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positron+emission+tomography+of+living+brain+in+minipigs+and+domestic+pigs.">Positron emission tomography of living brain in minipigs and domestic pigs.</a> Scand J Lab Anim Sci Suppl. 25 (1), 127-135 (1998).</li><li>R&#248;hl, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time+evolution+of+cerebral+perfusion+and+ADC+measured+by+MRI+in+a+porcine+stroke+model.">Time evolution of cerebral perfusion and ADC measured by MRI in a porcine stroke model.</a> J Magn Reson Imaging. 15 (2), 123-129 (2002).</li><li>Cumming, P., Gillings, N. M., Jensen, S. B., Bjarkam, C. 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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+implantation+of+deep+brain+stimulation+electrodes+in+the+pontine+micturition+centre+of+the+minipig.">Long-term implantation of deep brain stimulation electrodes in the pontine micturition centre of the minipig.</a> Acta Neurochir. 151 (7), 785-794 (2009).</li><li>Rosendal, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+chronic+low+dose+treatment+with+ciclosporin+influence+the+brain?+A+histopathological+study+in+pigs.">Does chronic low dose treatment with ciclosporin influence the brain? A histopathological study in pigs.</a> Transplantation Proc. 37 (8), 3305-3308 (2005).</li><li>Nielsen, M. S., S&#248;rensen, J. C., Bjarkam, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+substantia+nigra+pars+compacta+of+the+minipig:+An+anatomical+and+stereological+study.">The substantia nigra pars compacta of the minipig: An anatomical and stereological study.</a> Brain Struct Funct. (4-5), 481-488 (2009).</li><li>S&#248;rensen, J. C., Bjarkam, C. R., Simonsen, C. Z., Danielsen, E., Geneser, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oriented+sectioning+of+irregular+tissue+blocks+in+relation+to+computerized+scanning+modalities.+Results+from+the+domestic+pig+brain.">Oriented sectioning of irregular tissue blocks in relation to computerized scanning modalities. Results from the domestic pig brain.</a> J Neurosci Methods. 104, 93-98 (2000).</li><li>Bjarkam, C. R., Pedersen, M., S&#248;rensen, J. 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Most experimental neuroscience studies are performed in small animal species, such as mice and rats, where access to the CNS is facilitated by a thin skull- and dural-thickness. However, in larger experimental animals like pigs1,4,8, sheep32, and non-human primates, the considerable thickness of these structures necessitates the use of robust instruments (table of materials) and proper entry points for sk...

Translational neuroscience studies in pigs have become increasingly popular during the last two decades. The large size of the pig brain enables the use of conventional clinical brain imagers and the direct use and testing of neurosurgical procedures and equipment from the human clinic1,2,3,4,5,6,7,8. In the last 20 years, pigs, especially minipigs (e.g., G&#246;ttingen minipig), have been used to examine neuromodulatory treatment modalities, such as stem cell transplantation; viral vector transfection; and deep brain stimulation directed towards Parkinson disease, obesity, depression, and Alzheimer disease2,6,9,10,11,12,13,14,15,16,17. This has been followed by the development of stereotaxic and surgical approaches to manipulate the minipig CNS3,18,19,20,21. The instituted CNS changes have been evaluated in live animals using brain imaging (PET10,13,22,24 and MR23), cystometry11,12,25, gait analysis17, neurological evaluation9,17, and postmortem examination based on histology and stereological analysis14,15,17,26,27,31. However, postmortem analysis requires the exposure and removal of the pig brain, which is not an easy task, as a thick, bony skull and a fibrous dural covering surround the pig brain.
The goal of this paper and instructional video is to describe how the postmortem pig brain and pituitary may be exposed and removed in an intact state in 15-20 min using non-motorized surgical tools. The instructional video and photographic illustrations show male minipigs (age: 6 months, bodyweight: 20-25 kg) used for an anatomical study on the minipig pituitary gland.

<table border="0" cellpadding="0" cellspacing="0" width="1036">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Heavy Scalpel Handle #4</td>
			<td style="width:191px;">FST (Fine Science Tools)</td>
			<td style="width:149px;">10008-13</td>
			<td style="width:481px;">Good for skin incision and soft tissue removal</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Non-Sterile Scalpel Blades #23</td>
			<td style="width:191px;">FST&#160;</td>
			<td>10023-00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scalpel Handle #7</td>
			<td style="width:191px;">FST&#160;</td>
			<td>10007-12</td>
			<td>Optimal for dural incision and precision work</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Non-Sterile Scalpel Blades #11</td>
			<td style="width:191px;">FST&#160;</td>
			<td>10011-00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Surgical Forceps</td>
			<td style="width:191px;">FST&#160;</td>
			<td>11024-18</td>
			<td>The tip of the surgical forceps ensure a firm grip&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Kerrison Bone Punch</td>
			<td style="width:191px;">Aesculap Neurosurgery</td>
			<td style="width:149px;">FF713R</td>
			<td>Must be robust, bite size 3-5 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bone Rongeur</td>
			<td>Aesculap Neurosurgery</td>
			<td style="width:149px;">MD615</td>
			<td>Must be robust, bite size 15 x 5 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bone Rongeur</td>
			<td>Aesculap Neurosurgery</td>
			<td style="width:149px;">FO551R</td>
			<td>Must be robust, bite size 25 x 15 mm&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bone Chisel</td>
			<td>Lawton</td>
			<td>67-0335</td>
			<td>The size of the chisel head should not exceed 20 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mallet (Hammer)</td>
			<td>Millarco</td>
			<td>5624108</td>
			<td>Weigth 300 g, length 30 cm, head hit area size 2 x 2 cm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micro-Scissor</td>
			<td>FST&#160;</td>
			<td>14002-14&#160;&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dissector</td>
			<td>Aesculap Neurosurgery</td>
			<td style="width:149px;">OL165R</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">&#160;G&#246;ttingen minipigs</td>
			<td style="width:191px;">&#160;Ellegaard G&#246;ttingen Minipigs A/S, Denmark</td>
			<td style="width:149px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Euthanimal</td>
			<td style="width:191px;"></td>
			<td style="width:149px;"></td>
			<td>pentobarbital</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ketamine</td>
			<td style="width:191px;">Pfizer</td>
			<td style="width:149px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Midazolam&#160;</td>
			<td style="width:191px;">Hameln Pharmaceuticals</td>
			<td style="width:149px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

exposure of the pig cns for histological analysis: a manual for decapitation, skull opening, and brain removal

Pigs have become increasingly popular in large-animal translational neuroscience research as an economically and ethically feasible substitute to non-human primates. The large brain size of the pig allows the use of conventional clinical brain imagers and the direct use and testing of neurosurgical procedures and equipment from the human clinic. Further macroscopic and histological analysis, however, requires postmortem exposure of the pig central nervous system (CNS) and subsequent brain removal. This is not an easy task, as the pig CNS is encapsulated by a thick, bony skull and spinal column. The goal of this paper and instructional video is to describe how to expose and remove the postmortem pig brain and the pituitary gland in an intact state, suitable for subsequent macroscopic and histological analysis.

To prevent the tissue material from drying out, it is recommended to store the removed brain and pituitary in a jar filled with fixative or isotonic saline immediately after macroscopic analysis has been performed. The tissue material may be stored in the fixative for years, whereas storage in isotonic saline, even in a refrigerator, will lead to tissue decay with time.
The removed pituitary may also be directly frozen by immers...

Watch this Scientific Journal Video about Exposure of the Pig CNS for Histological Analysis: A Manual for Decapitation, Skull Opening, and Brain Removal at JoVE.com

Exposure of the Pig CNS for Histological Analysis: A Manual for Decapitation, Skull Opening, and Brain Removal

The goal of this paper and instructional video is to describe how to expose and remove the postmortem pig brain and pituitary gland in an intact state, suitable for subsequent macroscopic and histological analysis.

Pigs have become increasingly popular in large-animal translational neuroscience research as an economically and ethically feasible substitute to ...

In this video, we present how to expose and remove the intact pig brain and the intact pituitary by opening the skull and dura. Ethics statement:Animal anesthesia and euthanasia were performed in accordance with Principles of laboratory animal care"and approved by the Danish Council for Animal Research Ethics. Anesthesia was induced in male Gottingen minipigs by an intramuscular injection of midazolam and ketamine.Five to ten minutes later, when the animals were deeply sedated, an ear vein was cannulated and a lethal overdose of sodium pentobarbital was given intravenously. To secure the animals were completely euthanized, the interdigital pain reflex was tested as previously shown. After proper euthanization, the animals were transcardially perfused with five liters of isotonic saline.All the procedures demonstrated are, accordingly, performed postmortem, excluding the need for welfare precautions necessary for long term anesthesia and post-procedural survival. Instruments used. Heavy scalpel handle number four, and non-sterile scalpel blades, number 23.Good for skin incisions, and soft tissue removal. Scalpel handle number seven, and non-sterile scalpel blades, number 11. Optimal for dural incision, and precision work.Surgical forceps, with a bite that ensures a firm grip. KAIRison Bone Punch. Must be robust, with a bite size of three to five millimeters.Bone rongeur. Must be robust and have a bite size around five to 15 millimeters, for delicate bone work. Larger bone rongeur.With a bite size around 25 times 15 millimeters, for removal of thicker bone pieces. Bone chisel. The head should not be larger than 20 millimeters.A mallet, suitable for the bone chisel. Micro scissors, with a sharp tip.Dissector.Decapitation. The pig is decapitated by making a high circular cervical incision, just below the mandibular angle.Continue the incision, through the soft tissue of the neck. Cut through larynx, and esophagus, until the bone and spinal column is reached. Approximately at the level of the cranio-cervical junction.Advance the incision from the anterior side of the cranio-cervical junction, through the anterior atlantooccipital membrane. Whereby the spinal cord is exposed. Simultaneously, an assistant will pull the pig body away from the pig head, as this will ease the access between the skull base and the first cervical vertebra.Make sure the spinal cord is completely severed, before a forceful extension at the cranio-cervical junction finalizes the decapitation. Skull opening. Place a dorsal longitudinal incision through the skin and underlying soft tissue.From the back of the snout over the vertex of the head and down through the posterior part of the occipital region. Expose the dorsal and posterior part of the skull by removing soft tissue located lateral to the initial incision. Release the temporal muscle from the skull.Clean the posterior occipital bone from soft tissue. Use the posterior interest of the foramen magnum to remove the occipital bone in order to expose the dura-covered cerebellum. Return to the anterior side of the skull and select an entry point in the frontal bone, just in front of the eyes.At this point, use a bone chisel to penetrate the skull, and enter the frontal sinus. Use the extent of the frontal sinus for further removal of the other skull lamina. An inner thin skull lamina covering the cerebrum, is exposed.Open this lamina gently, to expose the dura covering the anterior part of the brain. Continue the bone removal laterally, through the temporal and parietal bone. In order to release the final part of the skull, located between the already-exposed parts of the cerebrum and cerebellum.Use the chisel to break open the remaining posterior skull bone, from one side, just like one opens a door. Brain removal. Lift the dura, for gentle incision close to the sagittal sinus.Use a dural opening for further removal of the dural sac covering the brain. Special care must be taken when removing the dura situated between the cerebrum and the cerebellum. As preservation of this dural leaf will prevent subsequent brain removal.Finally, the dura covering the cerebellum and the lower brain stem is sectioned. Position the pig head vertically, and release the cerebrum by blunt dissection of the olfactory bulbs from the dura-covered skull base. Section the exposed optic chiasm.Follow it by subsequent exposure and section of the pituitary stalk, and the oculomotor nerves. Release the brain stem by sectioning of the lower cranial nerves. Use a chisel to release the brain from the skull base.Pituitary removal. In the skull base, identify the pituitary stalk, with surrounding dural leaf. Cut the dural leaf laterally to the pituitary stalk.Use a dissector to release the pituitary, and lift it out of the pituitary fossa. Results and conclusion. The described technique enables safe removal of the postmortem pig brain and pituitary, in approximately 15 to 20 minutes.The obtained tissue may be submitted for microscopic analysis followed by oriented sectioning, into smaller brain slabs. The slabs are suitable for chemical analysis, or further histological processing.

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A Polished and Reinforced Thinned-skull Window for Long-term Imaging of the Mouse Brain

In vivo imaging of cortical function requires optical access to the brain without disruption of the intracranial environment. We present a method to form a polished and reinforced thinned skull (PoRTS) window in the mouse skull that spans several millimeters in diameter and is stable for months. The skull is thinned to 10 to 15 &mu;m in thickness with a hand held drill to achieve optical clarity, and is then overlaid with cyanoacrylate glue and a cover glass to: 1) provide rigidity, 2) inhibit bone regrowth and 3) reduce light scattering from irregularities on the bone surface. Since the skull is not breached, any inflammation that could affect the process being studied is greatly reduced. Imaging depths of up to 250 &mu;m below the cortical surface can be achieved using two-photon laser scanning microscopy. This window is well suited to study cerebral blood flow and cellular function in both anesthetized and awake preparations. It further offers the opportunity to manipulate cell activity using optogenetics or to disrupt blood flow in targeted vessels by irradiation of circulating photosensitizers.

We present a method to form an imaging window in the mouse skull that spans millimeters and is stable for months without inflammation of the brain. This method is well suited for longitudinal studies of blood flow, cellular dynamics, and cell/vascular structure using two-photon microscopy.

In vivo imaging of cortical function requires optical access to the brain without disruption of the intracranial environment. We present a method to form ...

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

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when studying the brain, as the functional role that a brain area fulfills may be largely defined by its connections to other brain areas. In this report, we describe a novel, non-invasive approach for relating brain structure and function using magnetic resonance imaging (MRI). This approach, a combination of structural imaging of long-range fiber connections and functional imaging data, is illustrated in two distinct cognitive domains, visual attention and face perception. Structural imaging is performed with diffusion-weighted imaging (DWI) and fiber tractography, which track the diffusion of water molecules along white-matter fiber tracts in the brain (Figure 1). By visualizing these fiber tracts, we are able to investigate the long-range connective architecture of the brain. The results compare favorably with one of the most widely-used techniques in DWI, diffusion tensor imaging (DTI). DTI is unable to resolve complex configurations of fiber tracts, limiting its utility for constructing detailed, anatomically-informed models of brain function. In contrast, our analyses reproduce known neuroanatomy with precision and accuracy. This advantage is partly due to data acquisition procedures: while many DTI protocols measure diffusion in a small number of directions (e.g., 6 or 12), we employ a diffusion spectrum imaging (DSI)1, 2 protocol which assesses diffusion in 257 directions and at a range of magnetic gradient strengths. Moreover, DSI data allow us to use more sophisticated methods for reconstructing acquired data. In two experiments (visual attention and face perception), tractography reveals that co-active areas of the human brain are anatomically connected, supporting extant hypotheses that they form functional networks. DWI allows us to create a "circuit diagram" and reproduce it on an individual-subject basis, for the purpose of monitoring task-relevant brain activity in networks of interest.

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.

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when ...

Manual Drainage of the Zebrafish Embryonic Brain Ventricles

Cerebrospinal fluid (CSF) is a protein rich fluid contained within the brain ventricles. It is present during early vertebrate embryonic development and persists throughout life. Adult CSF is thought to cushion the brain, remove waste, and carry secreted molecules1,2. In the adult and older embryo, the majority of CSF is made by the choroid plexus, a series of highly vascularized secretory regions located adjacent to the brain ventricles3-5. In zebrafish, the choroid plexus is fully formed at 144 hours post fertilization (hpf)6. Prior to this, in both zebrafish and other vertebrate embryos including mouse, a significant amount of embryonic CSF (eCSF) is present . These data and studies in chick suggest that the neuroepithelium is secretory early in development and may be the major source of eCSF prior to choroid plexus development7.
eCSF contains about three times more protein than adult CSF, suggesting that it may have an important role during development8,9. Studies in chick and mouse demonstrate that secreted factors in the eCSF, fluid pressure, or a combination of these, are important for neurogenesis, gene expression, cell proliferation, and cell survival in the neuroepithelium10-20. Proteomic analyses of human, rat, mouse, and chick eCSF have identified many proteins that may be necessary for CSF function. These include extracellular matrix components, apolipoproteins, osmotic pressure regulating proteins, and proteins involved in cell death and proliferation21-24. However, the complex functions of the eCSF are largely unknown.
We have developed a method for removing eCSF from zebrafish brain ventricles, thus allowing for identification of eCSF components and for analysis of the eCSF requirement during development. Although more eCSF can be collected from other vertebrate systems with larger embryos, eCSF can be collected from the earliest stages of zebrafish development, and under genetic or environmental conditions that lead to abnormal brain ventricle volume or morphology. Removal and collection of eCSF allows for mass spectrometric analysis, investigation of eCSF function, and reintroduction of select factors into the ventricles to assay their function. Thus the accessibility of the early zebrafish embryo allows for detailed analysis of eCSF function during development.

We present a method to collect cerebrospinal fluid (CSF) and to create a system which lacks CSF within the embryonic zebrafish brain ventricular system. This allows for further examination of CSF composition and its requirement during embryonic brain development.

Cerebrospinal fluid  (CSF) is a protein rich fluid contained within the brain ventricles. It is  present during early vertebrate embryonic development and ...

A Comprehensive Protocol for Manual Segmentation of the Medial Temporal Lobe Structures

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, hippocampus, and the associated parahippocampal regions (perirhinal, entorhinal,&#160;and parahippocampal proper). Unlike most other tracing protocols available, typically focusing on certain MTL areas (e.g., amygdala and/or hippocampus), the integrative perspective adopted by the present tracing guidelines allows for clear localization of all MTL subregions. By integrating information from a variety of sources, including extant tracing protocols separately targeting various MTL structures, histological reports, and brain atlases, and with the complement of illustrative visual materials, the present protocol provides an accurate, intuitive, and convenient guide for understanding the MTL anatomy. The need for such tracing guidelines is also emphasized by illustrating possible differences between automatic and manual segmentation protocols. This knowledge can be applied toward research involving not only structural MRI investigations but also structural-functional colocalization and fMRI signal extraction from anatomically defined ROIs, in healthy and clinical groups alike.

The present work provides a comprehensive set of guidelines for manually tracing the medial temporal lobe (MTL) structures. This protocol can be applied to research involving structural and/or combined structural-functional magnetic resonance imaging (MRI) investigations of the MTL, in both healthy and clinical groups.

The present paper describes a comprehensive protocol for manual tracing of the set of brain regions comprising the medial temporal lobe (MTL): amygdala, ...

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at the synaptic level. The Active Zone (AZ) is the region at the presynaptic membrane that mediates neurotransmitter release and is composed of a dense collection of scaffold proteins. AZs of Drosophila melanogaster (Drosophila) photoreceptors undergo molecular remodeling after prolonged exposure to natural ambient light. Thus the level of neuronal activity can rearrange the molecular composition of the AZ and contribute to the regulation of the functional output.
Starting from the light exposure set-up preparation to the immunohistochemistry, this protocol details how to quantify the number, the spatial distribution, and the delocalization level of synaptic molecules at AZs in Drosophila photoreceptors. Using image analysis software, clusters of the GFP-fused AZ component Bruchpilot were identified for each R8 photoreceptor (R8) axon terminal. Detected Bruchpilot spots were automatically assigned to individual R8 axons. To calculate the distribution of spot frequency along the axon, we implemented a customized software plugin. Each axon&#39;s start-point and end-point were manually defined and the position of each Bruchpilot spot was projected onto the connecting line between start and end-point. Besides the number of Bruchpilot clusters, we also quantified the delocalization level of Bruchpilot-GFP within the clusters. These measurements reflect in detail the spatially resolved synaptic dynamics in a single neuron under different environmental conditions to stimuli.

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

Here we show how to quantify the number and spatial distribution of synaptic active zones in Drosophila melanogaster&#160;photoreceptors, highlighted with a genetically encoded molecular marker, and their modulation after prolonged exposure to light.

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at ...

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

Advances in next-generation sequencing technologies contribute to the identification of (candidate) disease genes for movement disorders and other neurological diseases at an increasing speed. However, little is known about the molecular mechanisms that underlie these disorders. The genetic, molecular, and behavioral toolbox of Drosophila melanogaster makes this model organism particularly useful to characterize new disease genes and mechanisms in a high-throughput manner. Nevertheless, high-throughput screens require efficient and reliable assays that, ideally, are cost-effective and allow for the automatized quantification of traits relevant to these disorders. The island assay is a cost-effective and easily set-up method to evaluate Drosophila locomotor behavior. In this assay, flies are thrown onto a platform from a fixed height. This induces an innate motor response that enables the flies to escape from the platform within seconds. At present, quantitative analyses of filmed island assays are done manually, which is a laborious undertaking, particularly when performing large screens.
This manuscript describes the &#34;Drosophila Island Assay&#34; and &#34;Island Assay Analysis&#34; algorithms for&#160;high-throughput, automated data processing and quantification of island assay data. In the setup, a simple webcam connected to a laptop collects an image series of the platform while the assay is performed. The &#34;Drosophila Island Assay&#34; algorithm developed for the open-source software Fiji processes these image series and quantifies, for each experimental condition, the number of flies on the platform over time. The &#34;Island Assay Analysis&#34; script, compatible with the free software R, was developed to automatically process the obtained data and to calculate whether treatments/genotypes are statistically different. This greatly improves the efficiency of the island assay and makes it a powerful readout for basic locomotion and flight behavior. It can thus be applied to large screens investigating fly locomotor ability, Drosophila models of movement disorders, and drug efficacy.

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

The island assay is a relatively new, cost-effective assay that can be used to evaluate the basic locomotor behavior of Drosophila melanogaster. This manuscript describes algorithms for automatic data processing and objective quantification of island assay data, making this assay a sensitive, high-throughput readout for large genetic or pharmacological screens.

Advances in next-generation sequencing technologies contribute to the identification of (candidate) disease genes for movement disorders and other ...

Novel Passive Clearing Methods for the Rapid Production of Optical Transparency in Whole CNS Tissue

Since the development of CLARITY, a bioelectrochemical clearing technique that allows for three-dimensional phenotype mapping within transparent tissues, a multitude of novel clearing methodologies including CUBIC (clear, unobstructed brain imaging cocktails and computational analysis), SWITCH (system-wide control of interaction time and kinetics of chemicals), MAP (magnified analysis of the proteome), and PACT (passive clarity technique), have been established to further expand the existing toolkit for the microscopic analysis of biological tissues. The present study aims to improve upon and optimize the original PACT procedure for an array of intact rodent tissues, including the whole central nervous system (CNS), kidneys, spleen, and whole mouse embryos. Termed psPACT (process-separate PACT) and mPACT (modified PACT), these novel techniques provide highly efficacious means of mapping cell circuitry and visualizing subcellular structures in intact normal and pathological tissues. In the following protocol, we provide a detailed, step-by-step outline on how to achieve maximal tissue clearance with minimal invasion of their structural integrity via psPACT and mPACT.

Here, we present two novel methodologies, psPACT and mPACT, for achieving maximal optical transparency and subsequent microscopic analysis of tissue vasculature in the intact rodent whole CNS.

Since the development of CLARITY, a bioelectrochemical clearing technique that allows for three-dimensional phenotype mapping within transparent tissues, ...

Chronic Implantation of Whole-cortical Electrocorticographic Array in the Common Marmoset

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent development of thin, flexible ECoG electrodes has enabled conduction of stable recordings of large-scale cortical activity. We have developed a whole-cortical ECoG array for the common marmoset. The array continuously covers almost the entire lateral surface of cortical hemisphere, from the occipital pole to the temporal and frontal poles, and it captures whole-cortical neural activity in one shot. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain. Marmosets have two advantages regarding ECoG recordings, one being the homologous organization of anatomical structures in humans and macaques, including frontal, parietal, and temporal complexes. The other advantage is that the marmoset brain is lissencephalic and contains a large number of complexes, which are more difficult to access in macaques with ECoG, that are exposed to the brain surface.These features allow direct access to most cortical areas beneath the surface of the brain. This system provides an opportunity to investigate global cortical information processing with high resolutions at a sub-millisecond order in time and millimeter order in space.

We have developed a whole-cortical electrocorticographic array for the common marmoset that continuously covers almost the entire lateral surface of cortex, from the occipital pole to the temporal and frontal poles. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain.

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent ...

Focused Ultrasound Induced Blood-Brain Barrier Opening for Targeting Brain Structures and Evaluating Chemogenetic Neuromodulation

Acoustically Targeted Chemogenetics (ATAC) allows for the noninvasive control of specific neural circuits. ATAC achieves such control through a combination of focused ultrasound (FUS) induced blood-brain barrier opening (FUS-BBBO), gene delivery with adeno-associated viral (AAV) vectors, and activation of cellular signaling with engineered, chemogenetic, protein receptors and their cognate ligands. With ATAC, it is possible to transduce both large and small brain regions with millimeter precision using a single noninvasive ultrasound application. This transduction can later allow for a long-term, noninvasive, device-free neuromodulation in freely moving animals using a drug. Since FUS-BBBO, AAVs, and chemogenetics have been used in multiple animals, ATAC should also be scalable for the use in other animal species. This paper expands upon a previously published protocol and outlines how to optimize the gene delivery with FUS-BBBO to small brain regions with MRI-guidance but without a need for a complicated MRI-compatible FUS device. The protocol, also, describes the design of mouse targeting and restraint components that can be 3D-printed by any lab and can be easily modified for different species or custom equipment. To aid reproducibility, the protocol describes in detail how the microbubbles, AAVs, and venipuncture were used in ATAC development. Finally, an example data is shown to guide the preliminary investigations of studies utilizing ATAC.

This protocol delineates steps necessary for the gene delivery through focused ultrasound blood brain barrier (BBB) opening, evaluation of the resulting gene expression, and measurement of neuromodulation activity of chemogenetic receptors through histological tests.

Acoustically Targeted Chemogenetics (ATAC) allows for the noninvasive control of specific neural circuits. ATAC achieves such control through a ...

Extraction and Dissection of the Domesticated Pig Brain

Use of the pig as a preclinical and translatable animal model has been well-documented and accepted by research fields investigating cardiovascular systems, gastrointestinal systems, and nutrition, and the pig is increasingly being used as a large animal model in neuroscience. Furthermore, the pig is an accepted model to study neurodevelopment as it displays brain growth and development patterns similar to what occurs in humans. As a less common animal model in neuroscience, surgical and dissection procedures on pigs may not be as familiar or well-practiced among researchers. Therefore, a standardized visual protocol detailing consistent extraction and dissection methods may prove valuable for researchers working with the pig. The following video showcases a technique to remove the pig brain while keeping the cortex and brainstem intact and reviews methods to dissect several commonly investigated brain regions including the brainstem, cerebellum, midbrain, hippocampus, striatum, thalamus, and medial prefrontal cortex. The purpose of this video is to provide researchers with the tools and knowledge necessary to consistently perform a brain extraction and dissection on the four-week-old pig.

This protocol details the technique for removal of the pig brain in its entirety and dissection of several brain regions commonly studied in neuroscience.

Use of the pig as a preclinical and translatable animal model has been well-documented and accepted by research fields investigating cardiovascular ...