The authors would like to thank the following for funding this work: generous start-up funds from the Department of Biomedical Engineering in Washington University, a McDonnell Center for Systems Neuroscience grant, a Office of Naval Research grant (Grant#: N000141210089) to B.R.

1. Odor Preparation and Delivery
<ol>
 <li>Dilute odor solutions in mineral oil by volume to achieve the desired concentration level. Store a 20 ml mixture of mineral oil and the odorant in a 60 ml glass bottle. Insert two syringe needles into a rubber stopper (gauge 19), one from the bottom and the other from the top, to provide an inlet and an outlet line. Seal the glass bottle with this rubber stopper and attach a custom designed activated carbon filter to the inlet line (Figure 1A).</li>
 <li>The c...

<ol>
	<li>Ache, B. W., Young, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olfaction:+diverse+species,+conserved+principles.">Olfaction: diverse species, conserved principles.</a> Neuron. 48, 417-430 (2005).</li><li>Laurent, G., Wehr, M., Davidowitz, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+representations+of+odors+in+an+olfactory+network.">Temporal representations of odors in an olfactory network.</a> Journal of Neuroscience. 16, 3837-3847 (1996).</li><li>Stopfer, M., Jayaraman, V., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odor+identity+vs.+intensity+coding+in+an+olfactory+system.">Odor identity vs. intensity coding in an olfactory system.</a> Neuron. 39, 991-1004 (2003).</li><li>Steven de Belle, J., Heisenberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Associative+odor+learning+in+Drosophila+abolished+by+chemical+ablation+of+mushroom+bodies.">Associative odor learning in Drosophila abolished by chemical ablation of mushroom bodies.</a> Science. 263, 692-695 (1994).</li><li>Cassenaer, S., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conditional+modulation+of+spike-timing-dependent+plasticity+for+olfactory+learning.">Conditional modulation of spike-timing-dependent plasticity for olfactory learning.</a> Nature. 482, 47-52 (2012).</li><li>Hallem, E. A., Carlson, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coding+of+odors+by+a+receptor+repertoire.">Coding of odors by a receptor repertoire.</a> Cell. 125, 143-160 (2006).</li><li>Raman, B., Joseph, J., Tang, J., Stopfer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporally+diverse+firing+patterns+in+olfactory+receptor+neurons+underlie+spatiotemporal+neural+codes+for+odors.">Temporally diverse firing patterns in olfactory receptor neurons underlie spatiotemporal neural codes for odors.</a> Journal of Neuroscience. 30, 1994-2006 (2010).</li><li>Perez-Orive, 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=Oscillations+and+sparsening+of+odor+representations+in+the+mushroom+body.">Oscillations and sparsening of odor representations in the mushroom body.</a> Science. 297, 359-365 (2002).</li><li>Naraghi, M., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant-induced+oscillations+in+the+mushroom+bodies+of+the+locust.">Odorant-induced oscillations in the mushroom bodies of the locust.</a> The Journal of Neuroscience. 14, 2993-3004 (1994).</li><li>Ochieng, S. A., Hallberg, E., Hansson, B. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fine+structure+and+distribution+of+antennal+sensilla+of+the+desert+locust,+Schistocerca+gregaria+(Orthoptera:+Acrididae).">Fine structure and distribution of antennal sensilla of the desert locust, Schistocerca gregaria (Orthoptera: Acrididae).</a> Cell and Tissue Research. 291, 525-536 (1998).</li><li>Burrows, M., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synaptic+Potentials+in+the+Central+Terminals+of+Locust+Proprioceptive+Afferents+Generated+by+Other+Afferents+from+the+Same+Sense+Organ.">Synaptic Potentials in the Central Terminals of Locust Proprioceptive Afferents Generated by Other Afferents from the Same Sense Organ.</a> Journal of Neuroscience. 13, 808-819 (1993).</li><li>Pouzat, C., Mazor, O., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+noise+signature+to+optimize+spike-sorting+and+to+assess+neuronal+classification+quality.">Using noise signature to optimize spike-sorting and to assess neuronal classification quality.</a> Journal of Neuroscience Methods. 122, 43-57 (2002).</li><li>Mazor, O., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+dynamics+versus+fixed+points+in+odor+representations+by+locust+antennal+lobe+projection+neurons.">Transient dynamics versus fixed points in odor representations by locust antennal lobe projection neurons.</a> Neuron. 48, 661-673 (2005).</li><li>Christensen, T. A., Pawlowski, V. A., Lei, H., Hildebrand, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-unit+recordings+reveal+context+dependent+modulation+of+synchrony+in+odor-specific+neural+ensembles.">Multi-unit recordings reveal context dependent modulation of synchrony in odor-specific neural ensembles.</a> Nature Neuroscience. 3, 927-931 (2000).</li><li>Pellegrino, M., Nakagawa, T., Vosshall, L. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+Sensillum+Recordings+in+the+Insects+Drosophila+melanogaster+and+Anopheles+gambiae.">Single Sensillum Recordings in the Insects Drosophila melanogaster and Anopheles gambiae.</a> J. Vis. Exp. (36), e1725 (2010).</li><li>Geffen, M. N., Broome, B. M., Laurent, G., Meister, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+Encoding+of+Rapidly+Fluctuating+Odors.">Neural Encoding of Rapidly Fluctuating Odors.</a> Neuron. 61, 570-586 (2009).</li><li>Ito, I., Ong, R. C., Raman, B., Stopfer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sparse+odor+representation+and+olfactory+learning.">Sparse odor representation and olfactory learning.</a> Nature Neuroscience. 11, 1177-1184 (2008).</li><li>Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olfactory+network+dynamics+and+the+coding+of+multidimensional+signals.">Olfactory network dynamics and the coding of multidimensional signals.</a> Nature Review Neuroscience. 3, 884-895 (2002).</li><li>Brown, S. L., Joseph, J., Stopfer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Encoding+a+temporally+structured+stimulus+with+a+temporally+structured+neural+representation.">Encoding a temporally structured stimulus with a temporally structured neural representation.</a> Nature Neuroscience. 8, 1568-1576 (2005).</li><li>MacLeod, K., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+mechanism+for+synchronization+and+temporal+patterning+of+odor-encoding+neural+assemblies.">Distinct mechanism for synchronization and temporal patterning of odor-encoding neural assemblies.</a> Science. 274, 976-979 (1996).</li><li>Wehr, M., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+afferent+and+central+temporal+patterns+in+the+locust+olfactory+system.">Relationship between afferent and central temporal patterns in the locust olfactory system.</a> The Journal of Neuroscience. 19, 381-390 (1999).</li><li>Moreaux, L., Laurent, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+firing+rates+from+calcium+signals+in+locust+projection+neurons+in+vivo.">Estimating firing rates from calcium signals in locust projection neurons in vivo.</a> Frontiers in Neural Circuits. 1, 1-13 (2007).</li><li>Galizia, C. G., Joerges, J., Kuttner, A., Faber, T., Menzel, 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+semi-in-vivo+preparation+for+optical+recording+of+the+insect+brain.">A semi-in-vivo preparation for optical recording of the insect brain.</a> Journal of Neuroscience Methods. 76, 61-69 (1997).</li><li>Galan, R. F., Sachse, S., Galizia, C. G., Hez, A. V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odor-driven+attractor+dynamics+in+the+antennal+lobe+allow+for+simple+and+rapid+olfactory+pattern+classification.">Odor-driven attractor dynamics in the antennal lobe allow for simple and rapid olfactory pattern classification.</a> Neural Computation. 16, 999-1012 (2004).</li><li>Kuebler, L. S., Schubert, M., Karpati, Z., Hansson, B. S., Olsson, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antennal+Lobe+Processing+Correlates+to+Moth+Olfactory+Behavior.">Antennal Lobe Processing Correlates to Moth Olfactory Behavior.</a> Journal of Neuroscience. 32, 5772-5782 (2012).</li><li>Silbering, A. F., Bell, R., Galizia, C. G., Benton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+Imaging+of+Odor-evoked+Responses+in+the+Drosophila+Antennal+Lobe.">Calcium Imaging of Odor-evoked Responses in the Drosophila Antennal Lobe.</a> J. Vis. Exp. (61), e2976 (2012).</li><li>Skiri, H. T., Galizia, C. G., Mustaparta, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Representation+of+Primary+Plant+Odorants+in+the+Antennal+Lobe+of+the+Moth+Heliothis+virescens+Using+Calcium+Imaging.">Representation of Primary Plant Odorants in the Antennal Lobe of the Moth Heliothis virescens Using Calcium Imaging.</a> Chemical Senses. 29, 253-267 (2004).</li></ol>

No conflicts of interest declared.

Most sensory stimuli evoke combinatorial responses that are distributed across ensembles of neurons. Hence, simultaneous monitoring of multi-neuron activity is necessary to understand how stimulus-specific information is represented and processed by neural circuits in the brain. Here, we have demonstrated extracellular multi-unit recording techniques to characterize odor-evoked responses at the first three processing centers along the insect olfactory pathway. We note that the techniques presented here have been used in ...

<table border="1">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Electrophysiology Equipment</td>
		</tr>
		<tr>
			<td>A.C. amplifier</td>
			<td>GRASS</td>
			<td>Model P55</td>
			<td>for single sensillum recordings</td>
		</tr>
		<tr>
			<td>Audio monitor (model 3300)</td>
			<td>A-M Systems</td>
			<td>940000</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Custom-made 16 channel pre-amplifier and amplifier</td>
			<td>Cal. Tech. Biology Electronics Shop</td>
			<td>&nbsp;</td>
			<td>for AL and MB recordings</td>
		</tr>
		<tr>
			<td>Data acquisition unit</td>
			<td>National Instruments</td>
			<td>BNC-2090</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Fiber optic light</td>
			<td>WPI</td>
			<td>SI-72-8</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Light source 115 V</td>
			<td>WPI</td>
			<td>NOVA</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Manual micromanipulator</td>
			<td>WPI</td>
			<td>M3301R</td>
			<td>for locust brain recordings</td>
		</tr>
		<tr>
			<td>Stereomicroscope1 on boom stand</td>
			<td>Leica</td>
			<td>M80</td>
			<td>for locust brain recordings</td>
		</tr>
		<tr>
			<td>Stereomicroscope2</td>
			<td>Leica</td>
			<td>M205C</td>
			<td>for single sensillum recordings</td>
		</tr>
		<tr>
			<td>Vibration-isolation table</td>
			<td>TMC</td>
			<td>63-500 series</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Motorized micromanipulator</td>
			<td>Sutter Instruments</td>
			<td>MP285/T</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Oscilloscope</td>
			<td>Tektronix</td>
			<td>TD2014B</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Electrodes/Construction Tools</td>
		</tr>
		<tr>
			<td>16-channel electrode</td>
			<td>NeuroNexus</td>
			<td>A2x2-tet-3mm-150-121</td>
			<td>for antennal lobe recordings</td>
		</tr>
		<tr>
			<td>Borosilicate capillary tubes with filament, ID 0.69 mm</td>
			<td>Sutter Instruments</td>
			<td>BF120-69-10</td>
			<td>for making glass electrodes</td>
		</tr>
		<tr>
			<td>Micropipette puller</td>
			<td>Sutter Instruments</td>
			<td>P-1000</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Function generator</td>
			<td>Multimeter Warehouse</td>
			<td>SG1639A</td>
			<td>for gold-plating electrodes</td>
		</tr>
		<tr>
			<td>Gold plating solution (non cyanide)</td>
			<td>SIFCO Industries</td>
			<td>NC SPS 5355</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Impedance tester</td>
			<td>BAK Electronics Inc.</td>
			<td>IMP-2</td>
			<td>for gold-plating electrodes</td>
		</tr>
		<tr>
			<td>Switch rotary</td>
			<td>Electroswitch</td>
			<td>C7D0123N</td>
			<td>for gold-plating electrodes</td>
		</tr>
		<tr>
			<td>Pulse isolator</td>
			<td>WPI</td>
			<td>A365</td>
			<td>for gold-plating electrodes</td>
		</tr>
		<tr>
			<td>Q series electrode holder</td>
			<td>Warner Instruments</td>
			<td>64-1091</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Silver wire 0.010" diameter</td>
			<td>A-M Systems</td>
			<td>782500</td>
			<td>ground electrode</td>
		</tr>
		<tr>
			<td>8 pin DIP IC socket</td>
			<td>Digikey</td>
			<td>ED90032-ND</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Borosilicate capillary tubes with filament, ID 0.58 mm</td>
			<td>Warner Instruments</td>
			<td>64-0787</td>
			<td>twisted wire tetrode construction</td>
		</tr>
		<tr>
			<td>Heat gun</td>
			<td>Weller</td>
			<td>6966C</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Rediohm-800 wire</td>
			<td>Kanthal Precision Technologies</td>
			<td>PF002005</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Titer plate shaker</td>
			<td>Thermo Scientific</td>
			<td>4625Q</td>
			<td>twisting wires</td>
		</tr>
		<tr>
			<td>Carbide scissors, 4.5"</td>
			<td>Biomedical Research Instr</td>
			<td>25-1000</td>
			<td>for cutting twisted tetrode wires</td>
		</tr>
		<tr>
			<td>Fine point tweezers</td>
			<td>HECO</td>
			<td>91-EF5-SA</td>
			<td>for teasing tetrode wires apart</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Odor Delivery</td>
		</tr>
		<tr>
			<td>6 ml syringe</td>
			<td>Kendall</td>
			<td>1180600777</td>
			<td>for custom designed activated carbon filter</td>
		</tr>
		<tr>
			<td>Brown odor bottles</td>
			<td>Fisher</td>
			<td>08-912-165</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Charcoal</td>
			<td><a href="http://BuyActivatedCharcoal.com" target="_blank">BuyActivatedCharcoal.com</a></td>
			<td>GAC-48C</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Desiccant</td>
			<td>Drierite</td>
			<td>23005</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Drierite gas drying jar</td>
			<td>Fischer Scientific</td>
			<td>09-204</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Heat shrink tubing</td>
			<td>3M</td>
			<td>EPS-200</td>
			<td>odor filter preparation</td>
		</tr>
		<tr>
			<td>Hypodermic needle aluminum hub, gauge 19</td>
			<td>Kendall</td>
			<td>8881-200136</td>
			<td>for providing inlet and outlet lines for odor bottles</td>
		</tr>
		<tr>
			<td>Mineral oil</td>
			<td>Mallinckrodt Chemicals</td>
			<td>6357-04</td>
			<td>for odor dilution</td>
		</tr>
		<tr>
			<td>Nalgene plastic tubing, 890 FEP</td>
			<td>Thermo Scientific</td>
			<td>8050-0310</td>
			<td>for carrier gas delivery</td>
		</tr>
		<tr>
			<td>Pneumatic picopump</td>
			<td>WPI</td>
			<td>sys-pv820</td>
			<td>for odor delivery</td>
		</tr>
		<tr>
			<td>Polyethylene tubing ID 0.86 mm</td>
			<td>Intramedic</td>
			<td>427421</td>
			<td>for odor bottle outlet connections and saline profusion tubing</td>
		</tr>
		<tr>
			<td>Stoppers</td>
			<td>Lab Pure</td>
			<td>97041</td>
			<td>for sealing odor bottles</td>
		</tr>
		<tr>
			<td>Time tape</td>
			<td>PDC</td>
			<td>T-534-RP</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tubing luer</td>
			<td>Cole-Parmer</td>
			<td>30600-66</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Vacuum tube</td>
			<td>McMaster-Carr</td>
			<td>5488K66</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Preparation/Dissection</td>
		</tr>
		<tr>
			<td>100 x 15 mm petri dish</td>
			<td>VWR International</td>
			<td>89000-304</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>18 AWG copper stranded wire</td>
			<td>Lapp Kabel</td>
			<td>4510013</td>
			<td>wire insulation is used as rubber gaskets</td>
		</tr>
		<tr>
			<td>22 AWG stranded hookup wire</td>
			<td>AlphaWire</td>
			<td>1551</td>
			<td>brain platform</td>
		</tr>
		<tr>
			<td>Batik wax</td>
			<td>Jacquard</td>
			<td>7946000</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dental periphery Wax</td>
			<td>Henry-Schein Dental</td>
			<td>6652151</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Electrowaxer</td>
			<td>Almore International</td>
			<td>66000</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Epoxy, 5 min</td>
			<td>Permatex</td>
			<td>84101</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hypodermic needle aluminum hub</td>
			<td>Kendall</td>
			<td>8881-200136</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Protease from Streptomyces griseus</td>
			<td>Sigma-Aldrich</td>
			<td>P5147</td>
			<td>for desheathing locust brain</td>
		</tr>
		<tr>
			<td>Suture thread non-sterile</td>
			<td>Fisher</td>
			<td>NC9087024</td>
			<td>for tying the abdomen after gut removal</td>
		</tr>
		<tr>
			<td>Vetbond</td>
			<td>3M</td>
			<td>1469SB</td>
			<td>for sealing amputation sites</td>
		</tr>
		<tr>
			<td>Dumont #1 forceps (coarse)</td>
			<td>WPI</td>
			<td>500335</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dumont #5 titanium forceps (fine)</td>
			<td>WPI</td>
			<td>14096</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dumont #5SF forceps (super-fine)</td>
			<td>WPI</td>
			<td>500085</td>
			<td>desheathing locust brain</td>
		</tr>
		<tr>
			<td>10 cm dissecting scissors</td>
			<td>WPI</td>
			<td>14393</td>
			<td>for removing legs and wings</td>
		</tr>
		<tr>
			<td>Vannas scissors (fine)</td>
			<td>WPI</td>
			<td>500086</td>
			<td>for removing cuticle, cutting the foregut</td>
		</tr>
		<tr>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>Saline Profusion</td>
		</tr>
		<tr>
			<td>Extension set with rate flow regulator</td>
			<td>Moore Medical</td>
			<td>69136</td>
			<td>for regulating saline flow</td>
		</tr>
		<tr>
			<td>IV administration set with Y injection site</td>
			<td>Moore Medical</td>
			<td>73190</td>
			<td>for regulating saline flow</td>
		</tr>
	</tbody>
</table>

multi-unit recording methods to characterize neural activity in the locust (schistocerca americana) olfactory circuits

Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits.
First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques.

Odor-evoked responses of a single ORN to two different alcohols are shown in the Figure 3D. Depending on the recording location (sensilla type, placement of the electrode) multi-unit recordings can be achieved.
A raw extracellular waveform from an AL recording is shown in Figure 6A. Action potentials or spikes of varying amplitudes originating from different PNs can be observed in this voltage trace. Although the locust antennal lobe has excitatory projection ...

Watch this Scientific Journal Video about Multi-unit Recording Methods to Characterize Neural Activity in the Locust Schistocerca Americana Olfactory Circuits at JoVE.com

Multi-unit Recording Methods to Characterize Neural Activity in the Locust Schistocerca Americana Olfactory Circuits

We demonstrate variations of the extracellular multi-unit recording technique to characterize odor-evoked responses in the first three stages of the invertebrate olfactory pathway. These techniques can easily be adapted to examine ensemble activity in other neural systems as well.

Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

Detection and interpretation of olfactory cues are critical for the survival  of many organisms. Remarkably, species across phyla have strikingly similar ...

multi-unit-recording-methods-to-characterize-neural-activity-locust

Research

JoVE Journal

Neuroscience

26.8K Görüntüleme.  Washington University in St. Louis. Biz omurgasız koku yolunun ilk üç aşamada koku-uyarılmış yanıtlar karakterize etmek ekstraselüler çoklu ünite kayıt tekniği varyasyonları göstermektedir. Bu teknikler kolayca başka sinir sistemlerinin topluluk etkinliği incelemek için adapte edilebilir.