LCA acknowledges funding from an NDSEG fellowship, the NSF GRFP, and the Friends of the McGovern Institute. EP acknowledges funding the Harry and Eunice Nohara UROP Fund, the MIT Class of 1995 UROP Fund, and the MIT UROP Fund. ESB acknowledges funding from NIH 2R44NS070453-03A1, the IET Harvey Prize, and the New York Stem Cell Foundation-Robertson Award. RD acknowledges funding from NIH EY017292. Michael Williams helped the team to organize and gather supplies prior to filming.

Note: All animal procedures were in accordance with the NIH guidelines and were approved by the Massachusetts Institute of Technology Committee on Animal Care.
1. Illuminator Fabrication
<ol>
	<li>Use a pair of sharp shears to cut a section of 250 &#181;m diameter plastic optical fiber that is at least 10 cm longer than the desired total illuminator length.</li>
	<li>Remove 15 - 20 cm of polyethylene jacket from one end of the plastic optical fiber using a 22 gauge wire stripper.</li>
	<li>Secure the distal most 3 - 5 cm of the stripped end of the fiber in a table vise clamp.</li>
	<li>Hold the jacketed end of the fiber taut in one hand with a constant steady pull. The fiber should be parallel to the floor, perpendicular to the vice. Maintain this constant tension on the fiber throughout heating and cooling (Steps 1.5 and 1.6 below) so that the fiber remains straight and taut as it thins.</li>
	<li>Using the lowest setting of a dual temperature heat gun (570/1,000 &#176;F,), heat the stripped section of the fiber until it is thinned to a diameter of 60 - 100 &#956;m, or about the diameter of a human hair.</li>
	<li>Maintain the constant tension on the fiber while allowing the fiber to cool. Failure to maintain tension may cause the fiber to curl.</li>
	<li>Confirm the diameter of the thinned tip under a dissecting microscope. Alternately, one may use calipers instead.
	<ol>
		<li>If the fiber is not thin enough, repeat steps 1.4 through 1.6 as needed to achieve the desired tip diameter.</li>
		<li>Optional if re-pulling, put a small mark at the narrowest portion of the fiber if it will be heated again so that the center of the heat gun targets the narrowest portion of the fiber.</li>
		<li>If the fiber is too thin, start over.</li>
	</ol>
	</li>
	<li>Once the fiber has full cooled and the desired diameter has been achieved, pinch the fiber 3 cm from the narrowest point on either side. With a quick, sharp pull along the axis of the fiber, separate the sides to create a tapered tip.</li>
	<li>Examine the tapered tip under a low power (e.g., 4X) on dissection microscope. If the tip is forked or curled (Figure 1f), discard the fiber.</li>
	<li>Prepare to etch the tapered tip by placing a piece of lab tape near the end of the tip, leaving the last 5 mm exposed. The tape protects the fiber from etching above the desired length of light emission. This tip length was selected based on thickness of primate cortex in the target region. A longer or shorter length could be exposed depending on the desired length of illumination. If a different etch tip length is desired, the edge of the lab tape can be moved closer to or farther from the tapered tip.</li>
	<li>Fold a small (~1 inch x 2 inch) square of 5 &#956;m silicon carbide lapping sheet over between the thumb and forefinger. Place the tip of the fiber between the two sides of the lapping sheet and gently etch the fiber using small circular motions, as if rolling a BB between the thumb and forefinger. Frequently rotate the fiber so that all sides are etched evenly. The fiber tip will appear &#8220;roughened&#8221; to the naked eye in areas that have been etched, while un-etched areas typically appear smooth.</li>
	<li>Repeat step 1.11 with a 3 &#956;m aluminum oxide lapping sheet.</li>
	<li>Affix a connector on the end of the illuminator opposite to the etched tip. This allows the illuminator to connect to an optical cable or laser. 
	Note: This method differs from the preferred method for fixing glass / silica optical fibers in ferrules. Because the metal ferrule is harder than the plastic optical fiber, polishing the fiber and ferrule as a unit after gluing can damage the plastic optical fiber as tiny shards of metal produced during the polishing process can embed themselves in flat-cleaved fiber.
	<ol>
		<li>Remove about 5 mm of the polyethylene jacket from the opposite end of the illuminator using a 22 gauge wire stripper.</li>
		<li>Cut the opposite end flat with a hot knife to smooth the surface.</li>
		<li>Polish the opposite end flat with successively finer lapping sheets: 5 &#181;m, 3 &#956;m, 1 &#956;m and 0.3 &#181;m.</li>
		<li>Insert the flat opposite end into a 260 &#181;m inner diameter stainless steel ferrule until it is flush with the end of the ferrule.</li>
		<li>Visually confirm that the opposite end is smoothly and evenly polished with a fiber microscope.</li>
		<li>Remove the fiber from the ferrule and tape the ferrule vertically on the edge of a table with the fiber pointing down.</li>
		<li>Fill a 1 mL syringe with plastic epoxy and attach a blunt 18 gauge needle to the syringe.</li>
		<li>Use the needle to apply epoxy down into the ferrule. Fill the ferrule completely with epoxy.</li>
		<li>Insert the fiber into the ferrule.</li>
		<li>Wipe any excess epoxy from polished surface of the fiber with a wet lint-free wipe prior to drying if needed. Otherwise, excess epoxy can be removed after 12 - 24 h.</li>
		<li>Store the fiber gently until calibration and place a dust cap over the ferrule.</li>
	</ol>
	</li>
</ol>
2. Illuminator Calibration and Quality Control
Note: These methods for calibration assess for light output non-linearity at different distances from the tip of the fiber. Uneven light distribution typically results from a &#8220;bumpy&#8221; or &#8220;wavy&#8221; taper.
<ol>
	<li>Create a light shielding diaphragm for the top of the integrating sphere using light absorbing foil (Figure 2). 
	Note: Wear gloves whenever handling light absorbing foil to prevent skin oils from creating light reflecting smudges.
	<ol>
		<li>Fold a 2&#8221; by 4&#8221; piece of light absorbing foil over on itself to form a 2&#8221; x 2&#8221; square. &#160;An alternative method is to cut a 2&#8221; x 2&#8221; square with one light absorbing side and one light reflecting side (i.e., a side of standard aluminum foil); however, the fold-over method is safer because it provides a dull edge for handling the diaphragm in the next step.&#160;</li>
		<li>Fold lab tape or electrical tape along the edges of the square to bind the non-folded edges. This both holds the sides together and protects against cuts from sharp edges.</li>
		<li>Puncture a hole in the center of the square using a 26 gauge needle.</li>
		<li>Remove the large screw on cap from the integrating sphere and cover the opening with the diaphragm. Place the hole over the center. If the diaphragm was created with one light absorbing and one light reflecting side, place the light absorbing side up and the light reflecting side down, facing the inside of the integrating sphere. 
		Note: To prevent dust and debris from entering the integrating sphere and to keep the hole centered, secure the diaphragm to the outside of the integrating sphere with lab tape.</li>
	</ol>
	</li>
	<li>Measure light output along the tip in 500 &#181;m increments using a micromanipulator or stereotaxic arm and an integrating sphere. 
	Note: Safety goggles of the appropriate wavelength should be worn whenever the laser is on.
	<ol>
		<li>Connect the opposite end of the fiber to a laser or light source, but do not trigger light output yet.</li>
		<li>Secure the illuminator to a stereotaxic holder (preferably with lab tape) with the tip 7 - 10 mm below the bottom of the holder.</li>
		<li>Screw the stereotaxic holder into the stereotaxic arm.</li>
		<li>Align the tip of the illuminator with the hole in the center of the diaphragm. Zero the micromanipulator when the tip is at the exact same level as the diaphragm.</li>
		<li>Turn off the room lights and zero the integrating sphere.</li>
		<li>Trigger the laser (or other light source) and measure the total light power output using the integrating sphere. 
		Note: Use the lowest light output possible for calibration testing.</li>
		<li>Lower the fiber 500 &#181;m into the integrating sphere and repeat step 2.2.6.</li>
		<li>Continue lowering the fiber into the integrating sphere and measuring total light output in 500 &#181;m increments until the total light power levels off. 
		Caution: Total light power should level off once the entire tip is in the sphere. Do not continue to lower the fiber more than 1 - 2 mm beyond the etched tip length. If the tip contacts the bottom of the integrating sphere, it may melt and/or ruin the integrating sphere.</li>
	</ol>
	</li>
	<li>Confirm an evenly etched fiber by plotting total light power output as a function of how far the fiber has been lowered into the integrating sphere to confirm linearity.</li>
</ol>
3. In Vivo Illumination
Note: Here, these methods are shown using a plastic model rather than a non-human primate.
<ol>
	<li>Implant a 25 mm diameter recording chamber was implanted over the brain area of interest prior to experimentation.</li>
	<li>Perform anatomical magnetic resonance imaging (MRI) prior to experimentation. Place a custom recording grid in the chamber and fill it with sterile surgical lubricant to allow for grid visualization and determination of the level of the dura and target brain structures.</li>
	<li>Prepare a tower micro-drive prior to each testing session.
	<ol>
		<li>Affix a 25 gauge guide tube with beveled tip to the middle and lower clamps on the drive. Two clamps are used to ensure that the guide tube remains straight. Both of these clamps can be moved manually if desired. 
		Note: The guide tube may be epoxied or soldered to the clamps.</li>
		<li>Secure the large volume illuminator in the upper clamp on the same drive. This clamp is attached to the drive motor.</li>
		<li>Thread the large-volume illuminator through the guide tube fully and confirm that the tip of the illuminator extends past the tip of the guide tube. 
		Note: The length of illuminator that extends past the tip of the guide tube equals the distance from the dura to the lower margin of the target brain region, as determined via MRI.</li>
		<li>Soak the guide tube and illuminator in antiseptic solution (e.g., chlorohexidine) to sterilize.</li>
	</ol>
	</li>
	<li>Place a custom sterilized grid inside the clean chamber and secure it at a pre-specified orientation with a screw on the side of the chamber. The grid shown here has 1 mm spacing; however, the spacing can be customized as needed. 
	Note: This should be identical to the grid and orientation used in the anatomical MRI.</li>
	<li>Secure the stereotactic micro-drive holder on the recording chamber in a pre-determined orientation.</li>
	<li>Retract the sterilized illuminator from the guide tube by pulling the illuminator up using sterile, blunt forceps. The tip of the illuminator should be 5 - 10 mm above the tip of guide tube. 
	Note: The illuminator will bow outward between the guide tube and the clamp. This will not damage the flexible illuminator.</li>
	<li>Affix the micro-drive to the holder and place the guide tube into target grid hole.</li>
	<li>Lower the micro-drive stage until the guide tube is just through the level of the dura. 
	Note: If desired, a second micro-drive with an electrode can be placed on the stage and lowered into a different grid hole. The local field potential on this electrode will show a distance-dependent light artifact, which can be used to confirm illuminator placement.</li>
	<li>Attempt the lower the illuminator manually with sterile forceps.
	<ol>
		<li>If there is any resistance, retract the illuminator 5 - 10 mm, wait 10 min to allow the tissue to settle and try again.</li>
		<li>If there is still resistance on the second attempt, retract the illuminator tip into the guide tube, lower the guide tube 0.25 mm, and try again.</li>
		<li>Repeat until the illuminator slides through the guide tube without any resistance.</li>
		<li>Lower the illuminator until it is taut. 
		Caution: Do not push the illuminator forcefully against resistance. In these cases the guide tube typically has not penetrated the dura fully. Pushing the fiber forcefully will cause it to bend on itself, preventing the fiber from entering the brain and possibly destroying the tip (Figure 1g).</li>
	</ol>
	</li>
	<li>Connect the ferrule on the other end of the illuminator to the larger optics set up or laser.</li>
	<li>Ensure that no light is visible to the non-human primate.
	<ol>
		<li>Use black-out shielding or light absorbing foil to fully encompass the recording towers.</li>
		<li>Place all optical connections in shielded envelopes made of light absorbing foil.</li>
		<li>Shield all patch cables with either light absorbing foil or black electrical tape.</li>
		<li>As an extra precaution, place a decoy light-emitting diode (LED) bank of the same light color used in the experiment behind the non-human primate and flash the LEDs continuously at 2.5 Hz. This prevents the eyes from adjusting fully to darkness. If there were inadvertent light leakage, this flashing light would help to prevent the leak from serving as a behavioral trigger.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Herculano-Houzel, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+brain+in+numbers:+a+linearly+scaled-up+primate+brain.">The human brain in numbers: a linearly scaled-up primate brain.</a> Front Hum Neurosci. 3, 31 (2009).</li><li>Tamura, K., 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+glass-coated+tungsten+microelectrode+enclosing+optical+fibers+for+optogenetic+exploration+in+primate+deep+brain+structures.">A glass-coated tungsten microelectrode enclosing optical fibers for optogenetic exploration in primate deep brain structures.</a> J Neurosci Meth. 211 (1), 49-57 (2012).</li><li>Diester, I., 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=An+optogenetic+toolbox+designed+for+primates.">An optogenetic toolbox designed for primates.</a> Nat Neurosci. 14 (3), 387-397 (2011).</li><li>Dai, J., Brooks, D. I., Sheinberg, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optogenetic+and+Electrical+Microstimulation+Systematically+Bias+Visuospatial+Choice+in+Primates.">Optogenetic and Electrical Microstimulation Systematically Bias Visuospatial Choice in Primates.</a> Curr biol. 24 (1), 63-69 (2014).</li><li>Ozden, I., 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+coaxial+optrode+as+multifunction+write-read+probe+for+optogenetic+studies+in+non-human+primates.">A coaxial optrode as multifunction write-read probe for optogenetic studies in non-human primates.</a> J Neurosci Meth. 219 (1), 142-154 (2013).</li><li>Ruiz, O., 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=Optogenetics+through+windows+on+the+brain+in+the+nonhuman+primate.">Optogenetics through windows on the brain in the nonhuman primate.</a> J Neurophysiol. 110 (6), 1455-1467 (2013).</li><li>Chuong, A. 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=Noninvasive+optical+inhibition+with+a+red-shifted+microbial+rhodopsin.">Noninvasive optical inhibition with a red-shifted microbial rhodopsin.</a> Nat Neurosci. 17 (8), 1123-1129 (2014).</li><li>Acker, L., Pino, E. N., Boyden, E. S., Desimone, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FEF+inactivation+with+improved+optogenetic+methods.">FEF inactivation with improved optogenetic methods.</a> Proc Natl Acad Sci U S A. 113 (46), 7297-7306 (2016).</li><li>Jazayeri, M., Lindbloom-Brown, Z., Horwitz, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Saccadic+eye+movements+evoked+by+optogenetic+activation+of+primate+V1.">Saccadic eye movements evoked by optogenetic activation of primate V1.</a> Nat Neurosci. 15 (10), 1368-1370 (2012).</li><li>Gerits, A., 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=Optogenetically+Induced+Behavioral+and+Functional+Network+Changes+in+Primates.">Optogenetically Induced Behavioral and Functional Network Changes in Primates.</a> Curr Biol. 22 (18), 1722-1726 (2012).</li><li>Ohayon, S., Grimaldi, P., Schweers, N., Tsao, D. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Saccade+modulation+by+optical+and+electrical+stimulation+in+the+macaque+frontal+eye+field.">Saccade modulation by optical and electrical stimulation in the macaque frontal eye field.</a> J Neurosci. 33 (42), 16684-16697 (2013).</li><li>Cavanaugh, J., 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=Optogenetic+inactivation+modifies+monkey+visuomotor+behavior.">Optogenetic inactivation modifies monkey visuomotor behavior.</a> Neuron. 76 (5), 901-907 (2012).</li></ol>

While optogenetic tools are widely used to study disease and physiology in rodents, the technical challenge of illuminating large brain volumes has limited the use of optogenetics in non-human primates. Pioneering studies in monkeys used large light power densities (~100 mW/mm2 to 20 W/mm2) to illuminate small volumes, perhaps &#60; 1 mm3, and reported modest behavioral effects with excitatory opsins in the cortex4,9,<s...

Optogenetic tools, which allow for millisecond-precise, light-driven neuronal control are widely used to study functional physiology and behavior in rodents and invertebrates. However, technical challenges have limited the use of optogenetics in the non-human primate brain, which has a volume ~100x larger than the rodent brain 1.
To facilitate optogenetics studies in non-human primates, an illuminator was designed to address two competing goals: large volume illumination and minimal penetration damage. Previous attempts to address one of these concerns have come at the expensive of the other. Bundles of fibers illuminate larger volumes but with increased diameter, and, thus, damage2,3. Tapered glass fibers reduce penetration damage, but narrowly focus light to light emitting surface areas &#60;100 &#181;m2 4,5. External brain illumination through a window in the dura circumvents the challenge of penetration damage and may allow for large volume illumination, but it can only be used for a few superficial brain areas6.
To create a large-volume, small diameter illuminator (Figure 1a), the tip of a plastic optical fiber is heat tapered and the core and cladding are etched (Figure 1b,c). Unlike other tapered fibers that focus light to a narrow point, the etching allows light to escape evenly out the sides of the tip, thus, distributing light broadly over a large area (Figure 1d,e). Because penetration damage is proportional to penetration diameter, this illuminator has no more penetration damage than a conventional fiber, yet it has &#62;100x the light emitting surface area and delivers light more broadly with 1/100th the light power density in a brain phantom (1.75% agarose) (Figure 1e). A Monte Carlo model (Figure 1f) illustrates the difference in light spread between a conventional fiber and the large volume illuminator when they have equal light power densities as their light emitting surfaces. Each illuminator is individually calibrated using an integrating sphere (Figure 2a,b) to ensure even light distribution along the tip (Figure 2c).
This large volume illuminator has been validated with optogenetic manipulation of both behavior and neuronal firing in non-human primates. The fiber tip length may be customized to any brain area and to each animal&#8217;s individual receptive field map. The illuminator may be paired with a penetrating electrode for neuronal recordings that span the length of illumination. Further, because the fiber can carry any color of visible light, it can be paired with any of the available optogenetic molecules available.

<table border="0" cellpadding="0" cellspacing="0" width="853">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Plastic optical fiber</td>
			<td style="width:323px;">Industrial fiber optics</td>
			<td style="width:64px;">SK-10</td>
			<td style="width:64px;">250 micron diameter, Super Eska line</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Wire stripper</td>
			<td style="width:323px;">Klein Tools</td>
			<td align="right" style="width:64px;">11047</td>
			<td>22 gauge</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Vise Clamp</td>
			<td style="width:323px;">Wilton</td>
			<td align="right" style="width:64px;">11104</td>
			<td>Generic table mount vice clamp</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Dual temperature heat gun</td>
			<td style="width:323px;">Milwaukee</td>
			<td style="width:64px;">8975-6</td>
			<td>570 / 1000&#176;F</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Lab marker</td>
			<td style="width:323px;">VWR</td>
			<td align="right" style="width:64px;">52877</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Dissection microscope</td>
			<td style="width:323px;">VistaVision</td>
			<td style="width:64px;">82027-156</td>
			<td>Stereo microscope w/ dual incandescent light, 2x/4x magnification, available from VWR</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Lab tape</td>
			<td style="width:323px;">VWR</td>
			<td style="width:64px;">89097-972</td>
			<td>4 pack of violet color; however, tape color does not matter</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Silicon carbide lapping sheet</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">LF5P</td>
			<td>5 micron grit, 10 pack</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Aluminum oxide lapping sheet</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">LF3P</td>
			<td>3 micron grit, 10 pack</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Aluminum oxide lapping&#160; sheet</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">LF1P</td>
			<td>1 micron grit, 10 pack</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Calcined alumina lapping sheet</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">LF03P</td>
			<td>0.3 micron grit, 10 pack</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Hot knife</td>
			<td style="width:323px;">Industrial fiber optics</td>
			<td style="width:64px;">IF370012</td>
			<td>60 Watt, heavy duty</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Fiber inspection scope</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">FS201</td>
			<td>optional</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Stainless Steel Ferrule</td>
			<td style="width:323px;">Precision fiber optics</td>
			<td style="width:64px;">MM-FER2003SS-265</td>
			<td>265 micron inner diameter</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">1 mL syringe</td>
			<td style="width:323px;">BD</td>
			<td style="width:64px;">14-823-30</td>
			<td>Luer-lok tip is preferable to reduce risk of leakage, but not strictly needed</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Plastic epoxy</td>
			<td style="width:323px;">Industrial fiber optics</td>
			<td>40 0005</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">18 gauge blunt needle</td>
			<td style="width:323px;">BD</td>
			<td align="right" style="width:64px;">305180</td>
			<td>1.5 inch length</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Lint-free wipe (KimWipe)</td>
			<td style="width:323px;">ThorLabs</td>
			<td>KW32</td>
			<td>available from many vendors</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Light absorbing foil</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">BKF12</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Electrical tape</td>
			<td style="width:323px;">3M</td>
			<td style="width:64px;">Temflex 1700</td>
			<td>Optional, may substitute other brands / models</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">26 gauge sharp needle&#160;</td>
			<td style="width:323px;">BD</td>
			<td align="right" style="width:64px;">305111</td>
			<td>0.5 inch length</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Micromanipulator</td>
			<td style="width:323px;">Siskiyou</td>
			<td style="width:64px;">70750000E</td>
			<td>may substitute other brands/models</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Steretactic arm</td>
			<td style="width:323px;">Kopf</td>
			<td align="right" style="width:64px;">1460</td>
			<td>may substitute other brands/models</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Laser safety goggles</td>
			<td style="width:323px;">KenTeK</td>
			<td>KCM-6012</td>
			<td>must be selected based on the color of laser used, example given here</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Laser or other light source</td>
			<td style="width:323px;">vortran</td>
			<td style="width:64px;">Stradus 473-50</td>
			<td>example of blue laser</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:403px;">Integrating sphere</td>
			<td style="width:323px;">ThorLabs</td>
			<td>S142C</td>
			<td>Attached power meter, also available from ThorLabs, item #PM100D</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:403px;">Ultem recording chamber</td>
			<td style="width:323px;">Crist instrument company</td>
			<td style="width:64px;">6-ICO-J0</td>
			<td>Customized with alignment notch</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Tower microdrive with clamps</td>
			<td style="width:323px;">NAN</td>
			<td style="width:64px;">DRTBL-CMS</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Guide tube</td>
			<td style="width:323px;">Custom</td>
			<td style="width:64px;">N/A</td>
			<td>Made from 25 gauge spinal needle (BD) or blunt tubing</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">NAN driver system</td>
			<td style="width:323px;">NAN</td>
			<td style="width:64px;">NANDrive</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Custom grid design</td>
			<td style="width:323px;">custom</td>
			<td style="width:64px;">custom</td>
			<td>plans available upon request</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Blunt forceps</td>
			<td style="width:323px;">FischerScientific</td>
			<td style="width:64px;">08-875-8A</td>
			<td>generic stainless steel blunt forceps</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:403px;">Digital calipers</td>
			<td style="width:323px;">Neiko</td>
			<td style="width:64px;">01407A</td>
			<td>available on amazon.com. May select a finer resolution caliper for more precise measurements.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:403px;">Patch cable</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">FG200LCC-custom</td>
			<td>This is one example of many possible patch cables. As long as the fiber diameter is less than or equal to the fiber diameter of the large volume illuminator and as long as the connectors interface, any patch cable (glass or plastic, vendor purchased or made in the lab) is fine for this application.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">Clear plastic dust caps</td>
			<td style="width:323px;">ThorLabs</td>
			<td style="width:64px;">CAPF</td>
			<td>Package of 25</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:403px;">ceramic split mating sleeve</td>
			<td style="width:323px;">Precision Fiber Products, Inc.</td>
			<td style="width:64px;">SM-CS1140S</td>
			<td></td>
		</tr>
	</tbody>
</table>

large volume, behaviorally-relevant illumination for optogenetics in non-human primates

This protocol describes a large-volume illuminator, which was developed for optogenetic manipulations in the non-human primate brain. The illuminator is a modified plastic optical fiber with etched tip, such that the light emitting surface area is &#62; 100x that of a conventional fiber. In addition to describing the construction of the large-volume illuminator, this protocol details the quality-control calibration used to ensure even light distribution. Further, this protocol describes techniques for inserting and removing the large volume illuminator. Both superficial and deep structures may be illuminated. This large volume illuminator does not need to be physically coupled to an electrode, and because the illuminator is made of plastic, not glass, it will simply bend in circumstances when traditional optical fibers would shatter. Because this illuminator delivers light over behaviorally-relevant tissue volumes (&#8776; 10 mm3) with no greater penetration damage than a conventional optical fiber, it facilitates behavioral studies using optogenetics in non-human primates.

The illumination of large brain volumes in non-human primates allows for behaviorally-relevant optogenetic manipulation. Acker et al. (2016) used this large volume illuminator with the red-shifted Halorhodopsin, Jaws 7 to study the temporal contribution of the frontal eye field (FEF) to memory-guided saccades in two rhesus monkeys. Specifically, FEF neurons were injected with a viral vector containing Jaws and then illuminated with red-light using the large volume illuminator during eithe...

Watch this Scientific Journal Video about Large Volume, Behaviorally-relevant Illumination for Optogenetics in Non-human Primates at JoVE.com

Large Volume, Behaviorally-relevant Illumination for Optogenetics in Non-human Primates

A protocol to build a tissue penetrating illuminator for delivering light over large volumes with minimal diameter is presented.

This protocol describes a large-volume illuminator, which was developed for optogenetic manipulations in the non-human primate brain. The illuminator is a ...

large-volume-behaviorally-relevant-illumination-for-optogenetics-non

Research

JoVE Journal

Behavior

8.0K Views.  Massachusetts Institute of Technology. A protocol to build a tissue penetrating illuminator for delivering light over large volumes with minimal diameter is presented.

Video: Large Volume, Behaviorally-relevant Illumination for Optogenetics in Non-human Primates

A Procedure to Study the Effect of Prolonged Food Restriction on Heroin Seeking in Abstinent Rats

In human drug addicts, exposure to drug-associated cues or environments that were previously associated with drug taking can trigger relapse during abstinence. Moreover, various environmental challenges can exacerbate this effect, as well as increase ongoing drug intake.
The procedure we describe here highlights the impact of a common environmental challenge, food restriction, on drug craving that is expressed as an augmentation of drug seeking in abstinent rats.
Rats are implanted with chronic intravenous i.v. catheters, and then trained to press a lever for i.v. heroin over a period of 10-12 days. Following the heroin self-administration phase the rats are removed from the operant conditioning chambers and housed in the animal care facility for a period of at least 14 days. While one group is maintained under unrestricted access to food (sated group), a second group (FDR group) is exposed to a mild food restriction regimen that results in their body weights maintained at 90% of their nonrestricted body weight. On day 14 of food restriction the rats are transferred back to the drug-training environment, and a drug-seeking test is run under extinction conditions (i.e.&#160;lever presses do not result in heroin delivery).
The procedure presented here results in a highly robust augmentation of heroin seeking on test day in the food restricted rats. In addition, compared to the acute food deprivation manipulations we have used before, the current procedure is a more clinically relevant model for the impact of caloric restriction on drug seeking. Moreover, it might be closer to the human condition as the rats are not required to go through an extinction-training phase before the drug-seeking test, which is an integral component of the popular reinstatement procedure.

A procedure that allows a demonstration of robust augmentation of drug seeking in food-restricted rats is described. Following heroin self-administration training, rats go through an abstinence period, in a drug-free environment, during which they are mildly food restricted. Drug seeking is then tested in the drug-associated environment.

In human drug addicts, exposure to drug-associated cues or environments that were previously associated with drug taking can trigger relapse during ...

Barnes Maze Testing Strategies with Small and Large Rodent Models

Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g.&#160;bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g.&#160;distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e.&#160;random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g.&#160;shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure.

The dry-land Barnes maze is widely used to measure spatial navigation ability in response to mildly aversive stimuli. Over consecutive days, performance (e.g.&#160;latency to locate escape cage) of control subjects improves, indicative of normal learning and memory. Differences between rats and mice necessitate apparatus and methodology changes that are detailed here.

Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land ...

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior

Kinesthetic awareness is important to successfully navigate the environment. When we interact with our daily surroundings, some aspects of movement are deliberately planned, while others spontaneously occur below conscious awareness. The deliberate component of this dichotomy has been studied extensively in several contexts, while the spontaneous component remains largely under-explored. Moreover, how perceptual processes modulate these movement classes is still unclear. In particular, a currently debated issue is whether the visuomotor system is governed by the spatial percept produced by a visual illusion or whether it is not affected by the illusion and is governed instead by the veridical percept. Bistable percepts such as 3D depth inversion illusions (DIIs) provide an excellent context to study such interactions and balance, particularly when used in combination with reach-to-grasp movements. In this study, a methodology is developed that uses a DII to clarify the role of top-down processes on motor action, particularly exploring how reaches toward a target on a DII are affected in both deliberate and spontaneous movement domains.

It is unclear how top-down signals from the ventral visual stream affect movement. We developed a paradigm to test motor behavior towards a target on a 3D depth inversion illusion. Significant differences are reported in both deliberate, goal-directed movements and automatic actions under illusory and veridical viewing conditions.

Kinesthetic awareness is important to successfully navigate the environment. When we interact with our daily surroundings, some aspects of movement are ...

Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with schizophrenia who are at familial high risk (FHR) may show similar cognitive and emotional changes. However, the neurological changes underlying the emergence of these symptoms remain unclear. This study sought to identify differences in frontal, striatal, and limbic regions in children and adolescents with FHR using functional magnetic resonance imaging. Groups of 21 children and adolescents at FHR and 21 healthy controls completed an emotional oddball task that relied on selective attention and the suppression of task-irrelevant emotional information. The standard oddball task was modified to include aversive and neutral distractors in order to examine potential group differences in both emotional and executive processing. This task was designed specifically to allow for children and adolescents to complete by keeping the difficulty and emotional image content age-appropriate. Furthermore, we demonstrate a technique for suitable fMRI registration for children and adolescent participants. This paradigm may also be applied in future studies to measure changes in neural activity in other populations with hypothesized developmental changes in executive and emotional processing.

This paper describes how to use the emotional oddball task and fMRI to measure brain activation in children and adolescents at familial high risk for schizophrenia (FHR).&#160;FMRI was used to measure differences in fronto-striato-limbic regions during an emotional oddball task. Children with FHR exhibited abnormal functional activation during adolescence.

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with ...

Uncovering Beat Deafness: Detecting Rhythm Disorders with Synchronized Finger Tapping and Perceptual Timing Tasks

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson&#8217;s disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder).

Behavioral tasks that allow for the assessment of perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) are presented. Synchronization of finger tapping to the beat of an auditory stimuli and detecting rhythmic irregularities provides a means of uncovering rhythm disorders.

A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here ...

A Procedure to Observe Context-induced Renewal of Pavlovian-conditioned Alcohol-seeking Behavior in Rats

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate drug-seeking behavior and prompt relapse in abstinent drug users. We have developed a procedure to study the behavioral and neural processes that mediate the impact of context on alcohol-seeking behavior in rats. Following acclimation to the taste and pharmacological effects of 15% ethanol in the home cage, male Long-Evans rats receive Pavlovian discrimination training (PDT) in conditioning chambers. In each daily (Mon-Fri) PDT session, 16 trials each of two different 10 sec auditory conditioned stimuli occur. During one stimulus, the CS+, 0.2 ml of 15% ethanol is delivered into a fluid port for oral consumption. The second stimulus, the CS-, is not paired with ethanol. Across sessions, entries into the fluid port during the CS+ increase, whereas entries during the CS- stabilize at a lower level, indicating that a predictive association between the CS+ and ethanol is acquired. During PDT each chamber is equipped with a specific configuration of visual, olfactory and tactile contextual stimuli. Following PDT, extinction training is conducted in the same chamber that is now equipped with a different configuration of contextual stimuli. The CS+ and CS- are presented as before, but ethanol is withheld, which causes a gradual decline in port entries during the CS+. At test, rats are placed back into the PDT context and presented with the CS+ and CS- as before, but without ethanol. This manipulation triggers a robust and selective increase in the number of port entries made during the alcohol predictive CS+, with no change in responding during the CS-. This effect, referred to as context-induced renewal, illustrates the powerful capacity of contexts associated with alcohol consumption to stimulate alcohol-seeking behavior in response to Pavlovian alcohol cues.

A procedure to study the capacity of an alcohol associated environmental context to trigger the renewal of alcohol-seeking behavior in rats is described.

Environmental contexts in which drugs of abuse are consumed can trigger craving, a subjective Pavlovian-conditioned response that can facilitate ...

Assessment of Social Cognition in Non-human Primates Using a Network of Computerized Automated Learning Device (ALDM) Test Systems

Fagot &#38; Paleressompoulle1 and Fagot &#38; Bonte2 have published an automated learning device (ALDM) for the study of cognitive abilities of monkeys maintained in semi-free ranging conditions. Data accumulated during the last five years have consistently demonstrated the efficiency of this protocol to investigate individual/physical cognition in monkeys, and have further shown that this procedure reduces stress level during animal testing3. This paper demonstrates that networks of ALDM can also be used to investigate different facets of social cognition and in-group expressed behaviors in monkeys, and describes three illustrative protocols developed for that purpose. The first study demonstrates how ethological assessments of social behavior and computerized assessments of cognitive performance could be integrated to investigate the effects of socially exhibited moods on the cognitive performance of individuals. The second study shows that batteries of ALDM running in parallel can provide unique information on the influence of the presence of others on task performance. Finally, the last study shows that networks of ALDM test units can also be used to study issues related to social transmission and cultural evolution. Combined together, these three studies demonstrate clearly that ALDM testing is a highly promising experimental tool for bridging the gap in the animal literature between research on individual cognition and research on social cognition.

Assessment of Social Cognition in Non-human Primates Using a Network of Computerized Automated Learning Device ALDM Test Systems

Fagot &#38; Paleressompoulle1 have published an automated learning device (ALDM) aimed at testing individual cognitive abilities in semi-free ranging monkeys. The main goal of our protocol is to use a network of ALDM test units to study social cognition in non-human primates.

Fagot &#38; Paleressompoulle1 and Fagot &#38; Bonte2 have published an automated learning device (ALDM) for the study of cognitive abilities of monkeys ...

The Social Dimension of Stress: Experimental Manipulations of Social Support and Social Identity in the Trier Social Stress Test

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations supportive behavior of other people as well as positive social relationships can act as powerful resources to cope with stress. In order to study the interplay between these variables, this protocol describes two effective experimental manipulations of social relationships and supportive behavior in the laboratory. In the present article, these two manipulations are implemented in the Trier Social Stress Test (TSST)&#8212;a standard stress induction paradigm in which participants are subjected to a simulated job interview. More precisely, we propose (a) a manipulation of the relationship between different protagonists in the TSST by making a shared social identity salient and (b) a manipulation of the behavior of the TSST-selection committee, which acts either supportively or unsupportively. These two experimental manipulations are designed in a modular fashion and can be applied independently of each other but can also be combined. Moreover, these two manipulations can also be integrated into other stress protocols and into other standardized social interactions such as trust games, negotiation tasks, or other group tasks.

Previous research on the social dimension of stress has focused on two important variables: social identity and social support. This protocol introduces an effective experimental manipulation of these two social variables and describes their implementation in a standard stress induction paradigm (Trier Social Stress Test).

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations ...

Using Facial Electromyography to Assess Facial Muscle Reactions to Experienced and Observed Affective Touch in Humans

"Affective" touch is believed to be processed in a manner distinct from discriminatory touch and to involve activation of C-tactile (CT) afferent fibers. Touch that optimally activates CT fibers is consistently rated as hedonically pleasant. Patient groups with impaired social-emotional functioning also show disordered affective touch ratings. However, relying on self-reported ratings of touch has many limitations, including recall bias and communication barriers. Here, we describe a methodological approach to study affective responses to touch via facial electromyography (EMG) that circumvents the reliance on self-report ratings. Facial EMG is an objective, quantitative, and non-invasive method to measure facial muscle activity indicative of affective responses. Responses can be assessed across healthy and patient populations without the need for verbal communication. Here, we provide two separate datasets demonstrating that CT-optimal and non-optimal touch elicit distinct facial muscle reactions. Moreover, facial EMG responses are consistent across stimulus modalities, e.g. tactile (experienced touch) and visual (observed touch). Finally, the temporal resolution of facial EMG can detect responses on timescales that supersede that of verbal reporting. Together, our data suggest that facial EMG is a suitable methodology for use in affective tactile research that can be used to supplement, or in some cases, supplant, existing measures.

We describe a protocol to assess facial muscle activity in response to experienced and observed tactile stimulation using facial electromyography.

"Affective" touch is believed to be processed in a manner distinct from discriminatory touch and to involve activation of C-tactile (CT) afferent fibers. ...

In Vivo Protocol of Controlled Subconcussive Head Impacts for the Validation of Field Study Data

Subconcussive hits pose a threat to neuronal health as they have shown to induce neuronal structural damage and functional impairment without causing outward symptomology and appear to be a key contributor to an irreversible neurodegenerative disease, chronic traumatic encephalopathy (CTE). In addition, athletes can incur more than 1,000 of these hits per season. The subconcussive soccer heading model (SSHM) is a relevant, reproducible, and leading method of isolating and examining the effects of these subconcussive head impacts. By controlling variables such as ball traveling speed, the frequency of impacts, interval, ball placement to the head, as well as by measuring head impact magnitude, the SSHM provides the scientific community with a superior avenue of investigating the acute subconcussive effects on neuronal health. In this paper, we demonstrate the utility of SSHM in studying a time-course expression of neurofilament-light polypeptide (NF-L) in plasma in a repeated measures fashion. NF-L is an axonal injury marker that has previously been shown to be elevated in boxers and football players following subconcussive head trauma. Thirty-four adult aged soccer players were recruited and randomly assigned to either a soccer heading (n = 18) or kicking (n = 16) group. The heading group executed 10 headers with soccer balls projected at a velocity of 25 mph over 10 min. The kicking group followed the same protocol with 10 kicks. Plasma samples were obtained before and at 0 h, 2 h, and 24 h after heading/kicking and assessed for NF-L expressions. The heading group showed a gradual increase in plasma NF-L expression and peaked at 24 h after the heading protocol, whereas the kicking group remained consistent across the time points. These results confirmed the NF-L data from clinical field studies, encouraging the use of SSHM to validate clinical subconcussion data.

The subconcussive soccer heading model is a safe and concise methodological approach to isolate and measure the effects of subconcussive head impacts.

Subconcussive hits pose a threat to neuronal health as they have shown to induce neuronal structural damage and functional impairment without causing ...