Hearing Research

Facilities and Equipment

The Hearing Research Group (HRG) houses and maintains a number of state-of-the-art shared facilities and resources. These resources aid in the research and training for all of our faculty, trainees and volunteers.

Hearing Assessments

Startle Suite

To examine hearing abilities and deficits the HRG maintains 8 behavioral test stations operated by hardware/software system from Kinder Scientific. This system has been customized to independently control a startle stimulus intensity and custom software allows for detailed statistical data analysis. The Startle Box Suite is customized to achieve hearing assessments across multiple species.

Sound Booths

The HRG has several sound booths that are utilized to create an environment free of external sounds for sensitive physiological recordings of brain activity.

Imaging and Microscopy


To examine specific neural circuits that underlie hearing the HRG uses optogenetics (the use of light to control genetically modified neurons) stimulation. To achieve this level of neural control we use a green stimulation fiber-coupled laser (Shanghai Dream Laser) and a blue stimulating fiber-coupled LED (Thor Labs). A light measurement meter (Thor) and TDT communicator allow for dual optogenetic/neurophysiological/behavior recordings.

The system contains several major features:
  1. A stereotaxic surgical set up (Narashige),
  2. A single-walled acoustic chamber with a TDT Neurophysiological set up,
  3. A compliment of electrodes allowing for the recording of up to 32 channels under neurophysiological and optogenetic stimulation
  4. An anti-vibration table with precision Microdrive (Newport CONEX-AGP)


Transmission Electron Microscopy (TEM)

The HRG maintains and manages an electron microscopy suite that houses a JEOL 1400 TEM with an accelerating voltage of 120 kV, a Leica EM UC VI ultramicrotome for cutting ultrathin tissue sections, and a wet lab with the fumehoods and vacuum oven necessary for preparing resins and stains for EM. The HRG uses the TEM to examine the ultrastructure and synapses of neurons throughout the auditory pathways in the brain.

Multiphoton Imaging

The HRG utilizes an advanced two-photon imaging system based on the Scientifica Hyperscope.  This instrument is capable of in vivo deep brain imaging, brain slice imaging and patch-clamp electrophysiology, optogeneitics, spatially targeted uncaging, and calcium imaging using high sensitivity GaAsP detectors.


The HRG has a dedicated surgical bay that is used for both stereotaxic and non-stereotaxic small animal surgeries. The suite contains a Leica M80 surgical stereoscope and Kopf 1900 series stereotaxic device.


To generate specific auditory stimuli/vocalizations the HRG uses an Avisoft UltraSoundGate single channel recording system with a high-quality condenser microphone (recording between 4 kHz to 120 kHz).


The HRG uses custom software (Matlab) and Bruel and Kjaer microphones to calibrate our instrumentation for the delivery of auditory stimuli, equalization of stimuli and the recording/measurements of sound pressure levels.


Merri Rosen, Ph.D.
Director, Hearing Research Group
Phone: 330.325.6516
Email: mrosen@neomed.edu

Hearing Research

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