We propose two options to configurations to analyze Fear conditioning:
- Conditioning and Test in 2 distinct apparatus
In this configuration, the animal is placed into 2 radically different contexts between conditioning and test sessions.
In this case, the 2 apparatus are both equipped with:
- a ventilated and soundproof cubicle. The foam looks different in the two apparatus (smooth white in the conditioning box, dark honeycomed foam in the test box). Thus, the two contexts look different to the animal.
- a square cage, a cylindric cage
- a metal grid, a smooth and a rough floor
- a very accurate tight infrared frame, in order to detect small movements, freezing behaviors, and rearings.
- a sound generator (sounds may be set in frequencey and volume), a speaker
The Test apparatus is furthermore equipped with a scrambled shock generator, with adjustable intensity.
- Conditioning and Test in the same apparatus
In this case, the context in which the animal is placed remains similar (same box) in conditioning and test sessions. However, both the floor and the shape of the cage may be changed between conditioning and test.
The apparatus has got all the equipments described above.
The apparatus are connected to an electronic interface, which formats the signals acquired by the sensors, and communicates the information from and to the computer.
The software allows :
- easy editing of exercises (task schedules), library of exercises
- recording of all locomotor movements, freezing, rearings, and of the activation of the electric shock, cue-lights, sound, clocks, …
- displaying behavioral outputs in real time
A software module is dedicated to the analysis of the recorded data. Il calculates output variables, as defined by the experimenter. As examples:
- number and duration of freezings,
- locomotor activity, rearing activity,
- kinetics (per customized time unit) of the freezing, activity and rearings,
- the delay between the emission of the sound and the begining of the freezing,
This software displays the results in a Microsoft Excel compatible datasheet.
Coupling with Electrophysiology / Optogenetics
We propose solutions to couple the analysis of the Fear conditioning with electrophysiological recordings and optogenetic activation.
- a rotation and rearing compensator, compatible with any optical commutator,
- a device to activate lasers. This accessory sends electric signals up to 500Hz. The experimenter decides the exact moment according to clocks or behavioral outputs at which a customized train of pulses may be sent to the laser to specifically activate the targeted bunch of neurons.