For example, a reduction in auditory input during the development of the auditory system in the mutants may lead to an increase in the innervation of some or all of the central auditory nuclei making the animals hypersensitive to acoustic stimuli, the octave band noise stimulus may set up an unusual resonance in the cochlea when the TM is malformed, or Tecta may be expressed in the brain.
These findings indicate that larger normalized N1m decrements were obtained for the pass-band stimulus (PB) compared to the stop-band stimulus (SB), and for the right hemisphere compared to the left.
A spatially narrow band stimulus at a relatively low spatial frequency was used to avoid artifacts generated by chromatic aberration in the chromatic stimuli (Bradley et al., 1992; Cottaris, 2003), and spatial frequency was not varied experimentally due to this constraint.
The second TS was a stop-band stimulus (SB) containing the center frequencies of the stop-band sections (0.59, 0.83, 1.19, 1.66, and 2.39 kHz) of the CFN.
The first TS was a pass-band stimulus (PB) composed of five spectral components corresponding to the centers of the pass-band sections (0.7, 1.0, 1.4, 2.0, 2.8 kHz) of the CFN.
Such a broad-band stimulus would activate a relatively large number of neurons that are tuned to different spatial frequencies.
Individual dipole source analysis was performed on the grand averaged data across all stimulus types after band-pass filtering between 18 and 80 Hz.
All five speakers were given a unique, complex 40 ms stimulus, build from band-pass filtered white noise with a tone overlay (see Table 1 and File S1).
To obtain spike rate vs intensity curves (response curves), we used acoustic broad band stimuli (100 ms duration, 1 40 kHz bandwidth) repeated five times each at 8 intensities, rising from 32 to 88 dB SPL.
Use of a narrow-band stimulus of relatively low spatial frequency will result in a high proportion of lowpass neurons responding, whereas only a subset of narrowly tuned neurons will respond.
