Neurons Responsive to Global Visual Motion Have Unique Tuning Properties in Hummingbirds

Gaede, A H; Goller, B; Lam, J P M; Wylie, D R; Altshuler, D L

Abstract

Neurons in animal visual systems that respond to
global optic flow exhibit selectivity for motion direction and/or velocity. The avian lentiformis mesencephali (LM), known in mammals as the nucleus of the
optic tract (NOT), is a key nucleus for global motion
processing [1–4]. In all animals tested, it has been
found that the majority of LM and NOT neurons
are tuned to temporo-nasal (back-to-front) motion
[4–11]. Moreover, the monocular gain of the optokinetic response is higher in this direction, compared
to naso-temporal (front-to-back) motion [12, 13].
Hummingbirds are sensitive to small visual perturbations while hovering, and they drift to compensate for
optic flow in all directions [14]. Interestingly, the LM,
but not other visual nuclei, is hypertrophied in hummingbirds relative to other birds [15], which suggests
enhanced perception of global visual motion. Using
extracellular recording techniques, we found that
there is a uniform distribution of preferred directions
in the LM in Anna’s hummingbirds, whereas zebra
finch and pigeon LM populations, as in other tetrapods, show a strong bias toward temporo-nasal motion. Furthermore, LM and NOT neurons are generally
classified as tuned to ‘‘fast’’ or ‘‘slow’’ motion [10, 16,
17], and we predicted that most neurons would be
tuned to slow visual motion as an adaptation for
slow hovering. However, we found the opposite
result: most hummingbird LM neurons are tuned to
fast pattern velocities, compared to zebra finches
and pigeons. Collectively, these results suggest a
role in rapid responses during hovering, as well as
in velocity control and collision avoidance during forward flight of hummingbirds.

Citation

Gaede, A. H., Goller, B., Lam, J. P. M., Wylie, D. R., & Altshuler, D. L. (2017). Neurons Responsive to Global Visual Motion Have Unique Tuning Properties in Hummingbirds. Current Biology, 26(2), 279-285

• Journal Article Type: Article
• Acceptance Date: Dec 12, 2016
• Publication Date: Jan 23, 2017
• Deposit Date: Jul 14, 2020
• Publicly Available Date: Jul 14, 2020
• Journal: Current Biology
• Print ISSN: 0960-9822
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 26
• Issue: 2
• Pages: 279-285
• Public URL: https://rvc-repository.worktribe.com/output/1393690
• Publisher URL: https://doi.org/10.1016/j.cub.2016.11.041