Summary

Vagus nerve stimulation som et redskab til at fremkalde Plasticitet i Pathways Relevant for Extinction Læring

Published: August 21, 2015
doi:

Summary

Vagus nerve stimulation (VNS) har vist sig som et redskab til at fremkalde målrettet synaptisk plasticitet i forhjernen til at ændre en række adfærd. Denne protokol beskriver, hvordan man gennemfører VNS at lette konsolideringen af ​​frygt udslettelse hukommelse.

Abstract

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory.

Introduction

Klassisk frygt condition giver en meget anvendt dyremodel til at studere biologiske grundlag af angstlidelser. Under frygt condition, er et afskrækningsmiddel stimulus (det ubetingede stimulus, USA, fx et fodchok) præsenterede i forbindelse med en neutral stimulus, såsom en tone og / eller en kontekst (den betingede stimulus, CS). Under frygt condition, dannes associationer mellem CS og USA. Til sidst præsentationen af ​​CS alene fremkalder en frygt reaktion (den betingede respons, CR). I frygt udslettelse, er CS præsenteres flere gange i mangel af USA, hvilket får CR til gradvist aftage 1. Således udslettelse af konditioneret frygt er en aktiv proces, hvor frygtsomme adfærdsmæssige reaktioner på neutrale stimuli dæmpes, når de ikke længere forudsige afskrækningsmiddel resultater. Udslettelse af betingede reaktioner kræver konsolidering af nye erindringer, der konkurrerer med lærde foreninger. Et kendetegn for angstlidelser er IMPAIRED udslettelse 2-4. Således udslettelse af konditioneret frygt i dyremodeller fungerer som et vigtigt paradigme både hæmmende læring og som en model for adfærd terapi for humane angstlidelser 5,6.

Fordi der er tæt sammenhæng mellem frygt og menneskelig angst, menes det, at disse undersøgelser kan give indsigt i den biologiske natur angst-relaterede lidelser såsom post-traumatisk stress disorder, og vil bidrage til at udvikle strategier til at behandle dem. Et vigtigt mål med præklinisk forskning er at støtte udryddelse læring og til at fremkalde målrettet plasticitet i udryddelse kredsløb til at konsolidere udslettelse læring. Vagus nerve stimulation (VNS) er en minimalt invasiv neuroprosthetic tilgang, der kunne bruges til at give stram tidsmæssig og kredsløb-specifik modulering af hjernen områder og synapser engageret i en igangværende opgave. En række nyere undersøgelser fra Michael Kilgard gruppe ved The University of Texas i Dallas harvist, at parring VNS med diskrete sensoriske eller motoriske stimuli (f.eks, en tone eller en arm pull) er yderst effektive til at fremme kortikal plasticitet at behandle tinnitus 7, eller at overvinde motoriske mangler efter slagtilfælde 8-10. Desuden ikke-kontingent VNS, der opstår inden for kort tid-vindue efter at lære på samme måde fremmer kortikal plasticitet og forbedrer hukommelsen konsolidering i rotter og mennesker 11-13.

I betragtning af den rolle vagus nerve i det parasympatiske pathway, er det ikke overraskende, at det kunne deltage i modulering minder og synaptisk plasticitet. Meget emotionelle begivenheder tendens til at producere stærkere erindringer end ikke-emotionelle minder. Dette er sandsynligvis på grund af påvirkning af stresshormoner på hukommelsen konsolidering. Posttraining administration af stresshormonet adrenalin forbedrer hukommelsen konsolidering i humane og ikke-humane dyr, men adrenalin ikke krydser blod-hjerne-barrieren 14, 15 </sup>. Derfor skal stress-induceret adrenalin frigivelse påvirke hjernen indirekte at øge hukommelsen konsolidering. Stærke beviser tyder på, at vagus nerve kan være forbindelsen mellem cirkulerende adrenalin og hjernen. Miyashita og Williams 16 syntes, at systemisk administration af adrenalin øget vagusnerven fyring, og forhøjede niveauer af noradrenalin i amygdala 17. Systemisk administration af adrenalin ikke forbedre hukommelsen konsolidering, når β-adrenerge receptorer er blokeret i amygdala 18 tyder på, at vagus nerve spiller en rolle i vejen, der forvandler følelsesmæssigt vække erfaringer i langsigtede minder.

Således parring VNS med uddannelse har potentiale til at forbedre hjernen ændringer, der understøtter hukommelse konsolidering og udsættelse for betingede signaler i fravær af armering øger konsolidering af udryddelse læring i rotter 19,20. Her beskriver vi anvendelsen af ​​VNS ensa værktøj til at fremme kortikal plasticitet og letter udslettelse af en betinget frygt reaktion.

Protocol

Alle procedurer, der er beskrevet i denne protokol udføres i overensstemmelse med NIH Guide til Pleje og anvendelse af forsøgsdyr, og de blev godkendt af Institutional Animal Care og brug Udvalg The University of Texas i Dallas. 1. Konstruktion af VNS Cuffs Skabe et boreværktøj ved afsavning den skarpe ende af en 22 G nål ½. Kør nu stumpe ende af 22 ½ G kanyle over en metal-fil flere gange for at glatte det. Hold nålen i en 45 ° vinkel til filen og køre den fl…

Representative Results

Dette afsnit viser eksempler på resultater, der kan opnås ved anvendelse VNS i kombination med udryddelse læring for at nedsætte ekspressionen af ​​det konditionerede frygt respons i rotter. For Dage 1 og 2 (Auditory Fear Conditioning) blev rotter uddannet på en auditiv frygt condition opgave, hvor potechok blev parret med en tone. På dag 3 (Pre Treatment Test), blev der toner præsenteres i mangel af potechok at måle frysning niveauer, og udlede erhvervelse betinget frygt reaktion. På dag 4 (behandling) rot…

Discussion

Vi præsenterer her en protokol, der bruges til at lette udslettelse af konditioneret frygt under en enkelt session for eksponering for konditioneret signaler 19 og til at modulere plasticitet i forløbet mellem infralimbic cortex og den basolaterale amygdala, der kan mediere udslettelse learning 20. Et afgørende skridt for succes i denne protokol er den korrekte levering af VNS under udslettelse træning. Derfor bør man være særlig opmærksom på at opførelsen af ​​manchet elektroder og p…

Disclosures

The authors have nothing to disclose.

Acknowledgements

This research was supported by the National Institute of Mental Health MH 086960-01A1 (Christa K. McIntyre).

Materials

Alcohol
Atropine Fisher A0132-5G
Betadine Henry Schein 69066950
Hydrogen peroxide  CVS 209478
Ketamine Henry Schein  1129300
Marcaine Henry Schein 6312615
Mineral Oil CVS 152355
Neosporin CVS 629451
Oxygen Home Depot 304179
Pennicillin Fisher PENNA-10MU
Propane Home Depot 304182
Xylazine Henry Schein 4019308
Tools
Jewelery Torch Smith Equipment 23-1001D
Sewing Needle Walgreens 441831
#5 Forceps (2) Fine Science Tools 11254-20
Soldering Iron Home Depot  203525863
AmScope SM-4TX-144A 3.5X-45X Circuit Board Boom Stereo Microscope + 144 LED AmScope SM-4TX-144A
Helping Hands A-M Systems  726200
Scalpel Blade Holder Fine Science Tools 10003-12
Metal File Home Depot 6601
Ruler Home Deopt 202035324
Curved Hemostats  Fine Science Tools 130009-12
Fine Scissors Fine Science Tools 14058-09
Spatula Fine Science Tools
Small Screwdriver Home Depot 646507
Magnetic Fixator Retraction System Fine Science Tools 18200-04, 18200-01, 18200-05
Heating Pad Walgreens 30294
Clippers Walgreens 277966
Sharpie Staples 125328
Ring Forceps Fine Science Tools 11103-09
Custom Micropipette Glass Tools (J shape and Straight) – Borosilicate glass Sutter Instrument B150-110-10
Adson Forceps Fine Science Tools 11006-12
Cuffs
Tubing Braintree Scientific Inc MRE-065
Platinum Iridium Wire Medwire 10IR9/49T
Gold Pins Mill-Max 1001-0-15-15-30-27-04-0
Suture Thread Henry Schein 100-5797
22 G Needles Fisher  14-815-525
Paper Tape Fisher  03-411-602
Solder Home Deopt 327793
Flux  Home Deopt 300142
Scalpel Blade, 10 or 15 Stoelting 52173-10
Silastic Laboratory Tubing .51 mm ID x .94 mm OD Fisher  508-002
Headcaps
Connector Pieces (male) Omnetics Connector Corporation A25001-004
Headcap pieces (female) Omnetics Connector Corporation A24001-004
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26 Gauge Solid Copper Wire Staples 1016882  
Surgery
Bone Screws Stoelting+CB33:C61 51457
Scalpel Blades, 10 or 15 Stoelting 52173-10
1 ml syringes Fisher 14-826-261
22 G Needles Fisher  14-815-525
27 G Needles Fisher 14-826-48
2" x 2" Gauze Fisher 22-362-178
Swabs Fisher 19-120-472
Puppy Pads PetCo 1310747
Kim Wipes Fisher 06-666-A
Chamber and Behavioral Setting 
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Cite This Article
Childs, J. E., Alvarez-Dieppa, A. C., McIntyre, C. K., Kroener, S. Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning. J. Vis. Exp. (102), e53032, doi:10.3791/53032 (2015).

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