Figure 1.
In chinchillas treated with gentamicin to ablate vestibular sensation bilaterally, pulse-frequency-modulated prosthetic stimulation partially restored a 3D vestibulo-ocular reflex with gain similar to that of normal animals. (Column 1) Mean head rotation and eye rotations of a normal chinchilla during 2 Hz 50°/s head rotations about mean horizontal (top), left-anterior/right-posterior (LARP, middle), and right-anterior/left-posterior (RALP, bottom) semicircular canal (SCC) axes in darkness. Each component of the 3D response is shown. This animal’s gains were higher than the average responses of 5 normal animals (thin dotted line in each panel). Head or eye traces are inverted as required to facilitate visual comparison; n=number of cycles averaged. (Column 2) Responses for a chinchilla treated bilaterally with gentamicin and implanted with electrodes in the three left SCCs, with prosthetic stimulation off. (Column 3) Responses of same animal to same head rotations, 3.5 h after activation of the multichannel prosthesis. (Adapted with permission from Della Santina et al., 2007).