See JAX Pipeline on the IMPC website for order of tasks for all mice tested

Project protocol: Auditory brainstem response

• Introduction
• Study design
• Workflow
• Equipment, software and supplies
• Procedure
• Measurements
• Experimental and technical parameters

Introduction

Auditory brainstem response test determines hearing sensitivity and other physiological parameters using evoked potential recordings in anesthetized mice.

Study design

Paradigm: Baseline study

Panel: Collaborative Cross

Number of strains: 18

Sex: Both

Age: 15-17 wks

Sample size: Three mice per sex

Number of cohorts: 1

Workflow

Step	Description	Equipment	Data collected
1	Mice are anesthetized and weighed	-	-
2	Each mouse is prepped for ABR	Auditory brainstem response system	-
3	ABRs are recorded	Auditory brainstem response system	Auditory brainstem response at 6, 12, 18, 24, 30 kHz

Equipment, software and supplies

• Auditory brainstem response system [See Experimental and technical parameters]
  • Audio signal generators, amplifiers and loudspeakers
  • Calibration equipment (microphone, etc)
  • EEG Needle electrodes
  • Biological amplifier and headstage
  • Sound attenuating chamber
  • Heating blanket
• Data acquisition hardware
• Software to control signal presentation and data acquisition
• Data Analysis software/database application

Procedure

1. Mice are anesthetized i.p. with ketamine-xylazine.
2. Each mouse is placed on a heating blanket in a sound chamber and sub dermal needle electrodes are inserted (active electrode on vertex, reference electrode overlying left bulla, ground electrode overlying right bulla).
3. Each mouse is placed unrestrained in a prone position, nose forward, at the calibrated distance from the leading edge of the speaker to the mouse's interaural axis, on a thermostatically controlled blanket, inside a sound attenuating booth.
4. ABRs are recorded for the following frequencies: 6, 12, 18, 24, 30 kHz.

 

Data QC: Once or twice annually, the calibration of the microphone used for sound delivery should be checked using a Bruel and Kjaer PULSE system with the Type 4231 calibrator or other equivalent calibration instrumentation suitable for use with high frequencies.

 

Measurements

LIMS field name	MPD variable name	Description	Units	Series	Primary measurement	Series order	MPD computed	Calculation	Method	Data type
Body weight	bw	body weight	g						body weight	Float
6kHz-evoked ABR threshold	pip_6	auditory brainstem response (ABR) threshold, sound pressure level, 6 kHz pip	dB	Yes	pip_6	1			ABR test	Float
12kHz evoked ABR threshold	pip_12	auditory brainstem response (ABR) threshold, sound pressure level, 12 kHz pip	dB	Yes	pip_6	2			ABR test	Float
18kHz evoked ABR threshold	pip_18	auditory brainstem response (ABR) threshold, sound pressure level, 18 kHz pip	dB	Yes	pip_6	3			ABR test	Float
24kHz evoked ABR threshold	pip_24	auditory brainstem response (ABR) threshold, sound pressure level, 24 kHz pip	dB	Yes	pip_6	4			ABR test	Float
30kHz evoked ABR threshold	pip_30	auditory brainstem response (ABR) threshold, sound pressure level, 30 kHz pip	dB	Yes	pip_6	5			ABR test	Float

Experimental and technical parameters

Equipment name	Auditory brainstem response system
Equipment manufacturer	Intelligent Hearing Systems
Equipment model	Smart EP
Software	Smart EP
Recording environment	Sound proof booth
Stimulus level	5
Anesthesia	Ketamine-Xylazine