Eye and head reflexes are essential in maintaining the orientation of gaze in space at all times such that retinal images are stabilized. Although the VOR in pigeons (like all lateral-eyed animals) has been reported as undercompensatory, during natural behaviors such as flight, birds must be able to maintain gaze stability, perhaps using concerted head movement involving the VCR, CCR and inertia (head responses) to maintain steady gaze. In addition, different functional roles for vestibular afferents based on discharge dynamics have been previously proposed. Irregularly firing afferents are known to be sensitive to anodal galvanic currents which seem to have little effect upon the angular VOR. It is postulated that the irregular afferents may play a more significant role in the functional pathways of head and neck responses to motion. In the present proposed series of experiments, three-dimensional gaze stability will first be determined in pigeons during rotational and linear motion, examining the relative contributions of the eye and head. Second, the effects of altering the input from irregularly firing afferents upon gaze stability will be determined. For both objectives, quantitative measures of interest will include eye-in-space, head-in-space, and eye-in-head.
| Haque, Asim; Zakir, Mridha; Dickman, J David (2009) Regeneration of vestibular horizontal semicircular canal afferents in pigeons. J Neurophysiol 102:1274-86 |
| Haque, Asim; Zakir, Mridha; Dickman, J David (2008) Recovery of gaze stability during vestibular regeneration. J Neurophysiol 99:853-65 |
| Haque, Asim; Huss, David; Dickman, J David (2006) Afferent innervation patterns of the pigeon horizontal crista ampullaris. J Neurophysiol 96:3293-304 |
| Haque, Asim; Dickman, J David (2005) Vestibular gaze stabilization: different behavioral strategies for arboreal and terrestrial avians. J Neurophysiol 93:1165-73 |
