logosm.gif (1133 bytes) PANEL OF BEHAVIORAL ASSAYS

FEAR CONDITIONING

This procedure is based on the methods described in: Maren S, Aharonov G, Fanselow MS (1997) Neurotoxic lesions of the dorsal hippocampus and Pavlovian fear conditioning in rats. Behav Brain Res 88:261-274.

Apparatus: two Plexiglas conditioning chambers (Med Associates, Inc. Georgia VT) each measuring 26 cm long, 18 cm high, and 18 cm wide, with a metal grid floor. Each chamber is contained within a larger sound-attenuating chamber with a fan providing 70 dB background noise, a 24 W white light, speaker, and a viewing window. MED-PC software, IBM-PC, power supply for conditioning chambers (Med Associates), two shock generators (Med Associates).

Procedure: During all phases of training and testing, animals should be moved in home cages to room or hallway outside of training/testing room. Animals should be transported to and from conditioning chambers via mouse housing cage with bedding.

Training
1. Place shock grid into conditioning chamber, place waste pan below shock grid.
2. Put several drops of mint extract odor (McCormick’s) onto a piece of an absorbent cotton pad.
3. Place pad in a 50 ml polypropylene tube cap.
4. Place cap into waste pan.
5. Turn on fan and power supply to conditioning chambers.
6. Program computer to deliver 20 sec tones at 120, 180, and 240 minutes after start of trial (3 tones total).
7. Program computer to have each tone terminate with a 1 sec footshock.
8. Program shock generator to deliver 1.0 mA footshock.
9. Program computer to leave house light on continuously throughout trial.
10. Place one animal into each conditioning chamber, close doors to both conditioning chamber and sound attenuating cubicle, and start computer program.
11. Record presence or absence of freezing behavior every 10 seconds.
12. Watch animal for 2-3 seconds to determine freezing behavior.
13. Freezing behavior defined as no visible movement except for respiration.
14. Remove animal from apparatus 5 minutes after start of the trial.
15. Freezing behavior prior to first tone presentation can be considered and analyzed as preshock or baseline freezing.
16. Freezing after first tone-shock pairing can be considered and analyzed as immediate post-shock freezing.
17. Also record reactivity to each shock (i.e. did animal flinch, run/jump and/or vocalize?).
18. At end of test, record presence or absence of fecal boli and/or urine in waste pan.
19. Clean shock grid and waste pan with 70% Ethanol/Water and allow to dry after each animal is tested.

Conditioned freezing to context test (performed 24 hours after training)
1. Put several drops of mint extract odor (McCormick’s) onto a piece of an absorbent cotton pad.
2. Place pad in a 50 ml polypropylene tube cap.
3. Place cap into waste pan.
4. Turn on fan and power supply to conditioning chambers.
5. Program computer to leave house light on continuously throughout trial.
6. Place one animal into each conditioning chamber, close doors to both conditioning chamber and sound attenuating cubicle, and start computer program.
7. Record presence or absence of freezing behavior every 10 seconds.
8. Remove animal from apparatus 8 minutes after start of the trial.
9. At end of test, record presence or absence of fecal boli and/or urine in waste pan.
10. Clean shock grid and waste pan with 70% Ethanol/Water and allow to dry after each animal is tested.

Conditioned freezing to tone test (performed 48 hours after training)
1. Place white Plexiglas walls, floor, and ceiling into conditioning chambers.
2. Ceilings should have several white plastic chain links dangling from them.
3. Place several drops of coconut extract (McCormick’s) onto piece of absorbent cotton pad.
4. Place pad in a 50 ml polypropylene tube cap.
5. Cover cap with wire mesh screen to prevent animal from accessing it.
6. Place cap on Plexiglas floor.
7. Turn on fan and power supply to conditioning chambers.
8. Program computer to turn on tone continuously two minutes after trial starts.
9. Place one animal into each conditioning chamber, close doors to both conditioning chamber and sound attenuating cubicle, and start computer program.
10. Record presence or absence of freezing behavior every 10 seconds.
11. Remove animal from apparatus 10 minutes after start of the trial.
12. At end of test, record presence or absence of fecal boli and/or urine on floor.
13. Clean shock grid and waste pan with 70% Ethanol/Water and allow to dry after each animal is tested.
14. Freezing behavior prior to tone presentation can be considered and analyzed as freezing in an altered context.
15. Freezing behavior after tone presentation can be considered and analyzed as conditioned freezing to tone.

Sensitivity to shock test (performed after 72 hours post-training)
1. Turn on fan and power supply to conditioning chambers.
2. Program computer to deliver 1 sec shock 5 seconds after prompting computer.
3. Place shock grid into conditioning chamber, place waste pan below shock grid.
4. Set shock generator to 0.05 mA.
5. Place animal into conditioning chamber and allow to 5 min to acclimate.
6. Prompt computer to deliver shock.
7. Record any noticeable flinch, run/jump, or vocalization response.
8. Flinch = modest interruption in ongoing behavior that does not involve gross locomotor response
9. Run/jump = significant interruption in ongoing behavior that involves gross locomotor response (e.g. running from one side of cage to other or jumping from stationary position).
10. Increase mA setting by 0.05 and repeat steps 6-7.
11. stop session when animal has displayed all three responses.


 <BACK>

ABC Home  |  Procedures  |  Helpful Hints  |  How to Begin  |  Prices  |  Policies   |  People
WUSM  |  WUNI  |   Other WUSM Cores