Transcranial direct current stimulation (tDCS) is a therapeutic technique proposed to treat psychiatric diseases. An animal model is essential for understanding the specific biological alterations evoked by tDCS. This protocol describes a tDCS mouse model that uses a chronically implanted electrode.
A subscription to JoVE is required to view this content. Sign in or start your free trial.
Method Article
Transcranial Direct Current Stimulation (tDCS) in Mice
In This Article
Summary
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique proposed as an alternative or complementary treatment for several neuropsychiatric diseases. The biological effects of tDCS are not fully understood, which is in part explained due to the difficulty in obtaining human brain tissue. This protocol describes a tDCS mouse model that uses a chronically implanted electrode allowing the study of the long-lasting biological effects of tDCS. In this experimental model, tDCS changes the cortical gene expression and offers a prominent contribution to the understanding of the rationale for its therapeutic use.
Introduction
Transcranial Direct Current Stimulation (tDCS) is a non-invasive, low-cost, therapeutic technique, which focuses on neuronal modulation through the use of low-intensity continuous currents1. There are currently two setups (anodal and cathodal) for tDCS. While the anodal stimulation exerts a current electric field too weak to trigger action potentials, electrophysiology studies have shown that this method produces changes in synaptic plasticity2. For example, evidence shows that tDCS induces long-term potentiation (LTP) effects such as increased peak amplitude of the excitatory postsynaptic potentials3
Access restricted. Please log in or start a trial to view this content.
Protocol
Individually-housed male adult (8-12 weeks) C57BL/6 mice were used in this experiment. Animals received proper care before, during and after experimental procedures with food and water ad libitum. All procedures were approved by the animal ethics committee from Federal University of Minas Gerais (protocol number 59/2014).
1. Electrode Placement
- Sedating and fixating the animal onto the stereotaxic apparatus
- Sterilize all the necessary surgical instruments.
Note. Surgical instruments were sterilized for 3 minutes at 440 °C. Cotton swabs were autoclaved at 20 psi (pounds ....
- Sterilize all the necessary surgical instruments.
Access restricted. Please log in or start a trial to view this content.
Results
The surgical protocol presented long-term implant stability for at least one month, with no inflammatory signals at the stimulated site nor any other undesired effect. All the animals survived the surgical procedure and tDCS sessions (n = 8). In this experiment, tDCS implants were positioned over the M1 and M2 cortices (+1.0 mm anterior-posterior and 0.0 mm lateral to bregma). One week later, tDCS (n = 3-4) and sham (n = 3) mice were stimulated for five consecutive days during 10 min at 0.......
Access restricted. Please log in or start a trial to view this content.
Discussion
In recent years, neurostimulation techniques have been entering clinical practice as a promising procedure to treat neuropsychiatric disorders23. To reduce the constraint imposed by the lack of knowledge of the mechanisms of neurostimulation, we presented here a tDCS mouse model carrying an electrode that can target brain regions. Since the electrode is chronically implantable, this animal model enables the investigation of long-lasting biological effects evoked by tDCS (for at least 1 month) in c.......
Access restricted. Please log in or start a trial to view this content.
Acknowledgements
We thank Mr. Rodrigo de Souza for assistance in maintaining mouse colonies. L.A.V.M is a CAPES postdoctoral fellow. This work was supported by the grant PRONEX (FAPEMIG: APQ-00476-14).
....Access restricted. Please log in or start a trial to view this content.
Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| BD Ultra-Fine 50U Syringe | BD | 10033430026 | For intraperitonially injection. |
| Shaver (Philips Multigroom) | Philips (Brazil) | QG3340/16 | For surgical site trimming. |
| Surgical Equipment | |||
| Model 940 Small Animal Stereotaxic Instrument with Digital Display Console | KOPF | 940 | For animal surgical restriction and positioning. |
| Model 922 Non-Rupture 60 Degree Tip Ear Bars | KOPF | 922 | For animal surgical restriction and positioning. |
| Cannula Holder | KOPF | 1766-AP | For implant positioning. |
| Precision Stereo Zoom Binocular Microscope (III) on Boom Stand | WPI | PZMIII-BS | For bregma localization and implant positioning. |
| Temperature Control System Model | KOPF | TCAT-2LV | For animal thermal control. |
| Cold Light Source | WPI | WA-12633 | For focal brightness |
| Tabletop Laboratory Animal Anesthesia System with Scavenging | VetEquip | 901820 | For isoflurane delivery and safety. |
| VaporGuard Activated Charcoal Adsorption Filter | VetEquip | 931401 | Delivery system safety measures. |
| Model 923-B Mouse Gas Anesthesia Head Holder | KOPF | 923-B | For animal restriction and O2 and isoflurane delivery. |
| Oxygen regulator, E-cylinder | VetEquip | 901305 | For O2 regulation and delivery. |
| Oxygen hose – green | VetEquip | 931503 | For O2 and isoflurane delivery. |
| Infrared Sterilizer 800 ºC | Marconi | MA1201 | For instrument sterilization. |
| Surgical Instruments | |||
| Fine Scissors - ToughCut | Fine Science Tools | 14058-11 | For incision. |
| Surgical Hooks | INJEX | 1636 | In House Fabricated - Used to clear the surgical site from skin and fur. |
| Standard Tweezers or Forceps | - | - | For skin grasping. |
| Surgical Consumables | |||
| Vetbond | 3M | SC-361931 | For incision closing. |
| Cement and Catalyzer KIT (Duralay) | Reliance | 2OZ | For implant fixation. |
| Sterile Cotton Swabs (Autoclaved) | JnJ | 75U | For surgical site antisepsis. |
| 24 Well Plate (Tissue Culture Plate) | SARSTEDT | 831,836 | For cement preparation. |
| Application Brush | parkell | S286 | For cement mixing and application. |
| Pharmaceutics | |||
| Xylazin (ANASEDAN 2%) | Ceva Pharmaceutical (Brazil) | P10160 | For anesthesia induction. |
| Ketamine (DOPALEN 10%) | Ceva Pharmaceutical (Brazil) | P30101 | For anesthesia induction. |
| Isoflurane (100%) | Cristália (Brazil) | 100ML | For anesthesia maintenance. |
| Lidocaine (XYLESTESIN 5%) | Cristal Pharma | - | For post-surgical care. |
| Ketoprofen (PROFENID 100 mg) | Sanofi Aventis | 20ML | For post-surgical care. |
| Ringer's Lactate Solution | SANOBIOL LAB | 7898153652145 | For post-surgical care. |
| TobraDex (Dexamethasone 1 mg/g) | Alcon | 631 | For eye lubrification and protection. |
| Stimulation | |||
| Animal Transcranial Stimulator | Soterix Medical | 2100 | For current generation. |
| Pin-type electrode Holder (Cylindrical Holder Base) | Soterix Medical | 2100 | Electrode support (Implant). |
| Pin-type electrode (Ag/AgCl) | Soterix Medical | 2100 | For current delivery (electrode). |
| Pin-type electrode cap | Soterix Medical | 2100 | For implant protection. |
| Body Electrode (Ag/AgCl Coated) | Soterix Medical | 2100 | For current delivery (electrode). |
| Saline Solution (0.9%) | FarmaX | 7896902206441 | Conducting medium for current delivery. |
| Standard Tweezers or Forceps | - | - | For tDCS setup. |
| Real Time Polymerase Chain Reaction | |||
| BioRad CFX96 Real Time System | BioRad | C1000 | For qPCR |
| SsoAdvancedTM Universal SYBR Green Supermix (5 X 1mL) | BioRad | 1725271 | For qPCR |
| Hard Shell PCR Plates PCT COM 50 p/ CFX96 | BioRad | HSP9601 | For qPCR |
| Microseal "B" seal pct c/ 100 | BioRad | MSB1001 | For qPCR |
References
- Filmer, H. L., Dux, P. E., Mattingley, J. B. Applications of transcranial direct current stimulation for understanding brain function. Trends in Neurosciences. 37 (12), 742-753 (2014).
- Nitsche, M. A., Paulus, W. Sustained exci....
Access restricted. Please log in or start a trial to view this content.
Reprints and Permissions
