[Vestibular evoked potentials in "Gallus Domesticus"].
Electrophysiological activity in response to linear acceleration stimuli was recorded from Gallus Domesticus by means of subcutaneous electrodes. This investigation had two purposes: 1) to obtain normative data for our laboratory, and 2) to rule out auditory and somatosensory contributions to the Vestibular Evoked Potentials (VsEP). The stimulus consisted of a sigmoid-shaped voltage function generated by a digital-to-analog converter. This signal was amplified, attenuated, and directed to a shaker (selenoid-based, linear mechanical vibrator). The animal's head was firmly attached to a small platform which in turn was coupled to the transducer. The recorded electrophysiological activity was filtered, amplified, and averaged over 256 stimulus presentations. The VsEP are composed of a positive wave, a prominent negativity, and three to five additional positive waves which occur within the first 10 milliseconds following the stimulus. The first three elements are the most robust components of the response. Latency/acceleration and amplitude/acceleration functions were constructed for each of these three waves. Clear and replicable responses were obtained at an acceleration of 2.00 g. At this level the amplitude of the components ranged between 3 and 5 microvolts. On the average, threshold responses were recorded at 0.0935 g. VsEP were not affected by high intensity white noise. However, bilateral intralabyrinthine injection of tetrodotoxin (TTX), a voltage-gated sodium channel blocker, abolished the responses. These results suggest that the activity recorded in response to linear acceleration stimuli is of vestibular origin.
Weisleder
P
P
Jones
T A
TA
Rubel
E W
EW
D000818:Animals; D002645:Chickens / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*
Potenciales evocados vestibulares en "Gallus Domesticus".