The Sound Attenuating Chamber is an isolation chamber that provides a controlled environment for sound, electromagnetic interference, and light. It is utilized for various conditioning experiments. It can also be used to study the effect of audiogenic stress on rodent behavior and bodily functions.

The Sound Attenuating Chamber can be utilized for several conditioning experiments since it is equipped with levers, nose poke apertures, a speaker, a shock grid (optional), and a food pellet dispenser for reinforcement. The chamber keeps external environmental noise from the laboratory, which can distract or affect the animal’s performance during experiments, and eliminates the need for operant conditioning. chamber.

MazeEngineers offers the Sound Attenuating Chamber.

Features

Key Components
  • Isolation cubicle
  • Self-Administration chamber
  • Control box
  • Simple and easy wire connections
  • Isolation Cubicle
  • 55cm x 42cm x 55cm (width x depth x height)
  • Dimensions can be customized
  • Multi-layer sound-proof insulation material that attenuates environmental disturbance
  • LED house light (manual)
  • Programmable ambient light
  • Programmable IR light
  • Automated IR light
  • Automated air circulation fan
  • Cameral holder
  • Pull-out floor shelf
  • Self-Administration Chamber - Components
  • Two levers or two nose poke apertures
  • Two cue lights
  • One pellet dispenser
  • Infusion pump
  • Frequency tone (optional)
  • Shocker (optional)
  • Self-Administration Chamber - Two Cue Lights
  • If the levers are used, each lever is equipped with a cue light of configurable colors (white, red, green or blue)
  • above the lever
  • If the nose pokes are used, each aperture is equipped with a cue light of configurable colors (white, red, green
  • or blue)
    Self-Administration Chamber - Nose Poke Apertures
  • Two nose poke apertures are mounted on the interaction panel, 1 cm above the floor
  • Aperture dimension: 1.3 x 1.2 x 1.2 cm width x height x depth
  •  Each aperture is equipped with an infrared sensor capable of detecting the insertion of the animal’s nose
  • Nose poke behaviors are used to determine the infusion reward or pellet reward
  • Self-Administration Chamber - Lever
  • Two levers are made of stainless steel and mounted on the interaction panel
  • Width: 1.6 cm for rats and 1 cm for mice
  • Self-Administration Chamber - Pellet Dispenser
  • The pellet dispenser is controllable by program. It delivers a pellet to the food receptacle given certain conditions.
  • The sensor on the receptacle detects a pellet being consumed by animal
  • 20 mg pellet dispenser is the default choice (tested with pellets from https://www.bio-serv.com/). 45 mg pellet
  • dispenser is also available if the user chooses to use it instead.
    Self-Administration Chamber - Frequency Tone
  • Syringe pump interior diameter 12 mm
  • Configurable RPM 0.5 – 60 pump speed
  • Configurable single infusion and maximum infusion amount
  • Vascular Access Harness
  • Tether kit for mouse
  • Most parts are from InstechLab.com
  • Self-Administration Chamber - Shocker
  • Shock current from 0.1 to 4.0 mA in 0.1 mA steps, programmable control
  • Removable grid – mouse rod diameter 4mm, spacing 5 mm; rat rod diameter 6mm, spacing 10mm
  • Start / stop is controlled by software or manually
  • Control Boxes
  • Connections: Five cables are connected between the control box and its self-administration chamber
  • The cage ID switch is located on the back panel. It is a 5-bit switch and the control box ID ranges from 0 up to 31. So, these control boxes work in a system of updating 32 self-administration boxes. If the cage ID is switched advertently, the system will behave incorrectly. You should not need to switch the cage ID.
  • Infusion Pump
  • Infusion button on the control box to release the pump (red arrow on the control box)
  • Move the red knot (blue arrow) to automatically move the plunger flange holder (green arrow) to the proper position
  • Insert the barrel flange (red arrow) and plunger flange into their holders
  • Fasten the screws
  • Main Controller
  • The main controller connects to the PC via a USB (RS-232) cable and communicates with Maze Engineers Self-Administration software (Conduct Self-Administration) on the PC.
  • The main controller connects to all cage control boxes via wireless communication. This eliminates the need for many cable connections between the main controller and chamber control boxes.
  • After the power is on for the main controller and chamber control boxes, the communication between the main controller and the control boxes will be automatically established. Please check the Comm Status on the chamber control box to make is on.
  • Documentation

    Introduction

    The Sound Attenuating Chamber is an isolation chamber that provides a controlled environment for sound, electromagnetic interference, and light. It is utilized for various conditioning experiments. It can also be used to study the effect of audiogenic stress on rodent behavior and bodily functions.

     

    The Sound Attenuating Chamber comprises several adjustable features. It contains multi-layer soundproof insulation, a manual LED light, programmable ambient and IR lights, an automated IR light, an automated circulation fan, a camera holder, a syringe pump, an infusion pump, and a pull-put floor shelf that allows easy removal of waste materials. The chamber is equipped with two levers, two nose poke apertures, and two cue lights for conditioning experiments. The cue lights are placed above the levers or nose poke apertures and can be configured to produce white, red, green, or blue light. An infrared sensor is equipped with a nose aperture that allows automatic detection of nose pokes. The chamber is also equipped with a 20 mg pellet dispenser, which dispenses pellets as a reward if the subject meets the desired conditioning criteria. Moreover, the chamber can also be equipped with a shocker or frequency tone if needed. Since the sound-attenuating chamber is already equipped with equipment for conditioning experiments, it eliminates the need for having separate operant conditioning chambers placed in a sound-attenuating chamber, which is usually the case for several experimental studies. 

     

    The Sound Attenuating Chamber keeps out external environmental noise from the testing area, which can distract or affect the animal’s performance during experiments. It also improves the quality of the auditory stimulus for auditory discrimination experiments since the inner walls of the chamber reduces the reflection of sound, which can cause distortions. Moreover, when multiple experiments with auditory stimuli are performed close to each other, an attenuating chamber is essential to eliminate interference between discriminating stimuli from different experiments.

    Apparatus and Equipment

    The Sound Attenuating Chamber is an isolation chamber equipped with multi-layer sound-proof insulation material, dual visible and IR light bulbs, a camera holder, and a pellet dispenser. The pellet dispenser is 20 mg; however, a 45 mg dispenser is also available. 

    It also contains two levers, two nose poke apertures, and two cue lights. The nose poke apertures are mounted 1 cm above the floor on an interactive panel and measure 1.3 x 1.2 x 1.2 cm (width × height × depth). The interaction panel also contains the two levers, which are made of stainless steel. They are available in different widths: 1.6 cm for rats and 1 cm for mice. 

    The chamber contains a syringe pump with an interior diameter of 12 mm. It has a configurable RPM of 0.5 – 60 pump speed. It also contains an infusion pump.

    The chamber can also be equipped with a shocker grid if needed for additional conditioning protocols. The grid is removable and produces a shock current from 0.1 to 4.0 mA in 0.1 mA steps. The shocks can be controlled by software or administered manually. 

    Training Protocol

    Fill the pellet dispenser before starting the experiment. Remove the tray beneath the chamber and remove any waste material between test sessions. 

    The following is a sample conditioning protocol to analyze resurgence behaviors using the sound-attenuating chamber. 

     

    Phase 1 (Baseline Testing)

    Place a subject in the sound-attenuating chamber. Illuminate the cue light on one of the levers. When the subject presses the target lever, deliver a food pellet. After that, when the subject presses the target lever, deliver a food pellet after a 15-second variable interval schedule of reinforcement. If the subject presses the other lever, deliver no food reward or consequences. Conduct twenty baseline sessions. After baseline sessions, divide the subject into three groups of six in which the target lever-pressing during the final three sessions is equal between groups. 

     

    Phase 2 (Treatment)

    Place the subject in the chamber. Illuminate the stimulus light on the target lever and illuminate one nose-poke aperture. However, don’t deliver the reward when the subject presses the target lever as done in phase 1. Instead, if the subject pokes its nose in the illuminated aperture, deliver a food pellet along with an alternative reinforcement according to a 15-second variable interval schedule of reinforcement. Conduct fifteen sessions. 

     

    Phase 3 (Resurgence Test)

    Conduct different treatments for each group during the resurgence test. For the control group, administer the food pellets in the same manner as Phase 2, such that the reinforcement contingencies remain the same. For the Resurgence-Control group, completely suspend the food pellets and food-correlated stimuli. For the Stimulus group, remove the tubing that connects the pellet dispenser to the food aperture. Therefore, nose pokes will only produce an audible click from the pellet dispenser without the reward. Conduct five sessions for each group. 

    Literature Review

    Investigation of resurgence behaviors in rodents using the Sound Attenuating Chamber

    Craig, Browning, and Shahan (2017) investigated whether delivering reinforcer-associated stimuli during resurgence testing mitigated resurgence. The experiment was conducted using an operant chamber housed in a sound-attenuating chamber. The operant chamber was equipped with levers, nose poke apertures, cue lights, and a pellet dispenser. Eighteen male Long-Evans rats ninety days old were divided into three groups of six and used in the experiment. The experiment was divided into three phases: baseline testing, treatment, and resurgence testing. The food pellets were delivered after pressing the lever in phase 1 and after nose pokes in phase 2, each after a variable 15-second interval schedule of reinforcement. During resurgence testing, trials were conducted in the same manner as phase 2 for the first group. For the second group, pellet dispensing and cue illumination were suspended. For the third group, only the food-correlated stimuli were produced without delivering the food reward. Results indicated that resurgence was lower in the group that received food correlated stimuli than it was for the group that received no consequences for nose pokes. Moreover, target-lever pressing did not increase in the first group between the three phases. However, it resurged for the second and third groups.

     

    Investigation of metacognition in rats using the Sound Attenuating Chamber 

    Foote and Crystal (2007) investigated metacognition in Sprague-Dawley rats using an operant chamber housed in a sound-attenuating chamber. The experiment was divided into study, choice, and test phases. During the study phase, a sound was presented to the subjects to classify as short (2–3.62 s) or long (4.42–8 s). The choice phase comprised of presenting the subject with either one or two response options. During one response option, a single nose-poke aperture was illuminated that the subject had to select, which led to the duration test, and the subject was not allowed to decline the test. During both response options, both the nose-poke apertures were illuminated. If the subject poked its nose in one of the apertures (which indicated accepting the test response), it led to the insertion of two response levers, which led to the duration test. During the duration test, the subject had to discriminate between short and long noise durations. The presentation of a short noise indicated one lever as the correct response, and a long noise indicated the other lever as the correct response. Nose pokes in the other aperture indicated declining the test response, and no duration test was produced. During the test phase, six large pellets were given as a reward if the correct lever was pressed with respect to the duration of discrimination. On the other hand, an incorrect lever press produced no reward. Declining a response in the test phase produced a smaller reward of three pellets. Results indicated that when the discrimination of the noises increased, the rate of declining the test also increased. Moreover, the accuracy of selecting the correct lever also declined as the difficulty of the discrimination increased. 

    Data Analysis

    The following parameters can be observed using the Sound Attenuating Chamber:

    • The number of correct lever responses
    • The number of incorrect lever response
    • The number of nose pokes in the correct nose poke aperture
    • The number of nose pokes in the incorrect nose poke aperture
    • Trial duration 

    Strengths and Limitations

    The Sound Attenuating Chamber allows conditioning experiments to be performed in a sound-controlled environment, eliminating the need to use operant chambers. It is equipped with two levers and two nose poke apertures, allowing the experimenter to utilize either or both during conditioning experiments. Moreover, the cue lights placed on the levers and nose poke aperture are configurable, so the experimenter can set the desired color during experiments or utilize different colored cue lights to challenge the subjects discriminating abilities. The chamber is also equipped with a speaker that can produce sounds within the frequency between 100-40,000 Hz. Moreover, it includes a pellet dispenser for delivering the food reward. The chamber can also be equipped with a shocker grid if needed. Therefore, the sound-attenuating chamber can be utilized for several different conditioning protocols since it is equipped with several different stimuli for reinforcement. 

    Summary

    • The Sound Attenuating  Chamber is an isolation chamber that provides a controlled environment for sound, electromagnetic interference, and light.
    • It can be utilized for several conditioning experiments since it is equipped with levers, nose poke apertures, a speaker, a shock grid (optional), and a food pellet dispenser for reinforcement. 
    • The Sound Attenuating  Chamber keeps external environmental noise from the laboratory, which can distract or affect the animal’s performance during experiments.
    • The Sound Attenuating Chamber eliminates the need for an operant conditioning chamber. 

    References

    1. Craig, A. R., Browning, K. O., & Shahan, T. A. (2017). Stimuli previously associated with reinforcement mitigate resurgence. Journal of the experimental analysis of behavior108(2), 139–150. https://doi.org/10.1002/jeab.278
    2. Foote, A. L., & Crystal, J. D. (2007). Metacognition in the ratCurrent biology : CB17(6), 551–555. https://doi.org/10.1016/j.cub.2007.01.061