Pci 6071e

Both experiments were conducted in a sound-attenuated and electrically shielded chamber dimply illuminated by DC-powered LED lighting. A height-adjustable LCD monitor presented stimuli at 120 Hz. Participants sat in a chair and viewed the monitor at a distance of approximately 57 cm and made their responses using a gamepad. A Windows-based computer controlled stimulus presentation and registered participants’ button presses using Presentation software (Neurobehavioral Systems, Berkeley, California). A custom software (Acquire) recorded electroencephalogram (EEG) from a second, Windows-based computer, which housed a 64-channel A-to-D board (PCI-6071e, National instruments, Austin, Texas) that connected to an EEG amplifier system with an input impedance of 1 GΩ (SA Instruments, San Diego, California). The stimulus-control and EEG-acquisition computers were situated outside of the testing chamber.

All experiments were performed in the same, sound-attenuated, electrical shielded chamber and experimental setup as described in earlier work (Boenke et al., 2009 (link)). The chamber had an ambient sound level of ∼28 dB(A) SPL and the setup was covered with black velvet cloth to avoid light reflections. A green light-emitting diode (LED) at eye level ∼165 cm from participants served as fixation. Two boxes were placed symmetrically ±38 cm left and right of the LED (∼ ± 13.0° visual angle), each containing a speaker with a white cover and a white LED light source mounted above the speaker inside the box. A 4 cm aperture in the front of the box revealed the speaker cone, and the white cover in front of it would appear as a white circle whenever the overhead LED was illuminated and was otherwise invisible. This set-up allows presentation of collocated light and sound sources with independent timing. Stimulus presentation and recording was controlled by a Matlab (R14) program running on an IBM 486-compatible microcomputer and participants responded on a custom-made hand-held response box. Stimulus timing was controlled by a National Instruments card (PCI-6071E, Austin, TX, USA) and was verified to be accurate to <1 ms.

We controlled the delivery of current or voltage and data acquisition with a National Instruments card (DAQ, PCI-6071E). We provided the current to our circuit with the DAQ connected to an Analog Stimulus Isolator (A-M Systems, model 2200). The membrane potential was acquired with an analog input of the same DAC, and the information was processed using LabVIEW (National Instruments, TX).

We developed custom made MATLAB (Natick, MA) code to simulate the spiking models, and to analyze all the simulations and experiments. We stimulated and acquired the data from the circuit with a National Instruments data acquisition card (DAQ, PCI-6071E). We provided the current to our circuit with the DAQ connected to an Analog Stimulus Isolator (A-M Systems, model 2200). The membrane potential was acquired with an analog input of the same DAC, and the information was processed using LabVIEW. We report 95% confidence intervals (95% CI) and Standard Error of the Mean (SEM).

Ipsilateral tones (right ear, 15 kHz at 80 dB SPL) and contralateral broadband noise (CBN) (left ear, 55–60 dB SPL) were digitally generated by two synchronized multifunction computer boards at 100,000 samples/s (PCI-6071-E, National Instruments^®, TX, USA), attenuated by PA-5 programmable attenuators (system III, Tucker Davis Technologies^®, FL, USA). We decided to use 15 kHz tones due to evidence of a higher density of olivocochlear innervation at this position of the cochlea in mice [24 (link)]. Auditory stimuli were delivered via two tweeters (one for ipsilateral and the second for contralateral auditory stimuli) (Realistic super tweeter, frequency response 5–40 kHz, Radioshack^®, TX, USA) through tubes sealed to the external auditory meatus. Ipsilateral tones were presented with alternating polarity at 4 Hz rate, 5 ms duration, and 0.5 ms rise/fall time and were used to obtain ipsilateral auditory brainstem responses and contralateral ACEP. Contralateral non-continuous broadband noise (5–40 kHz) was presented at 4 Hz with a duration of 170–200 ms.

ABRs signals were acquired through intradermal needle electrodes (low impedance (< 5 kΩ), 25G needle diameter) directed to the ear canal of both ears. Ground electrodes were placed in the midline of the animal [25 (link)]. The brainstem signal in response to ipsilateral stimulation (right ear) was amplified 10,000–100,000 times and filtered between 0.3 and 3 kHz. Data were digitized and stored for offline analyses at 40,000 samples per second using a multifunction acquisition card (PCI-6071-E, National Instruments^®, TX, USA) and a custom made software programmed in C language (LabWindows CVI 6.0, National Instruments, TX, USA).