The frequency response of rat vibrissae to sound

Abstract

The motion of isolated rat vibrissae due to low frequency sound has been modeled and measured with good agreement (within a factor of 2) between the data and the model's predictions. As had been done in previous studies on the response of rat vibrissae to tactile stimulation [Hartmann, M. J., Johnson, N. J., Towal, R. B., and Assad, C., J. Neurosci 23, 6510-6519 (2003) and Neimark, M. A., Andermann, A. L., Hopfield, J. J., and Moore, C. I., J. Neurosci 23, 6449-6509 (2003)] the vibrissae were modeled as thin conical beams. The force of the vibrating air on a vibrissa was modeled using the exact solution for a vibrating infinite cylinder in linear fluid. A finite element method was used to model the motion of a single vibrissa fixed at its base, using the aforementioned fluid force. Values for Young's modulus and vibrissa mass density were taken from a previous study [Neimark et al. (above)]. The model had no freely fitted parameters. Motion of isolated vibrissae was measured using a video camera with microscope. The sound stimulation was created using a stereo speaker connected to a signal generator. The tuning was found to be sharp, with quality factors that varied between 3 and 7, much sharper than the motion of cricket cercal hairs or in vitro inner ear hair bundles.

The Frequency Response of the Vibrissae of Harp Seal, Pagophilus Groenlandicus, to Sound in Air and Water

“…The experimental set-up in which the vibrissae motion was recorded is shown in Figure 3 and is also described in a previous study [3]. The vibrissae are stimulated by the motion of the surrounding fluid (air) that is driven by the sound coming from the speaker.…”

“…A needle glued to the speaker surface allowed measurement of the speaker displacement which was used to approximate the air displacement that was exciting the vibrissa. As in a previous study [3] the speaker displacement was divided by two to approximate the air displacement in the vicinity of the vibrissa, since it had been determined, using a velocity microphone, that the amplitude of the disturbance decreased by roughly a factor of two from a position next to the speaker to one in the vicinity of the vibrissa. More details about approximating the attenuation can be found in that study [3].…”

“…As in a previous study [3] the speaker displacement was divided by two to approximate the air displacement in the vicinity of the vibrissa, since it had been determined, using a velocity microphone, that the amplitude of the disturbance decreased by roughly a factor of two from a position next to the speaker to one in the vicinity of the vibrissa. More details about approximating the attenuation can be found in that study [3]. Detecting a resonant frequency was done by incrementing the signal generator in 1 Hz intervals and observing the motion with the video camera.…”

“…Rat vibrissae have been shown to be frequency selective in their response to tactile stimulation [1], [2], and to sound stimulation [3]. Frequency selectivity means that each vibrissa has a frequency or range of frequencies to which it responds best.…”

Mechanisms of Tactile Information Transmission through Whisker Vibrations

“…Together, these findings suggest that surface coarseness is not encoded by relative vibration amplitude across facial whiskers, at least in our experimental setup. Nevertheless, the occurrence of whisker resonance during passive and active whisker movements suggests that it may play a role in amplifying some types of whisker responses Shatz and Christensen, 2008).…”