Hough Lab

Description of Research Expertise

Contributions to Science

1.     Re-expression of songs deleted during song learning as potentially important signals for migratory assemblage. Classic songbird song learning theory stated that once a bird finished developing song, called crystallization, no further changes to song was possible. In these two studies, I challenged that view, performing two studies to test how permanent adult song was in a crystallized bird. Using two different songbird,species commonly used in song studies, I was able to show that crystallized song could be lost if a bird was prevented from hearing his own song, and that songs removed during selective attrition during development could be seasonally reexpressed. These studies indicate that adult song is much more flexible than previously thought.

a.     Hough II, G.E., Nelson, D.A., & Volman, S.F.  (2000). Re-expression of songs deleted during vocal development in white-crowned sparrows, Zonotrichia leucophrys.  Animal Behaviour, 60, 279-287. [Impact factor: 3.4].

b.     Hough II, G.E., & Volman, S.F.  (2002). Short- and long-term effects of vocal distortion on song maintenance in zebra finches.  Journal of Neuroscience, 22, 1177-1186. [Impact factor: 7.4]

2.     Characterization of how homing pigeons encode environmental space in the hippocampus. My graduate studies into adult song led me to my next research project in homing pigeons, which have been selectively bred by humans to be one of the finest spatial navigation organisms. Because of their unique ability to navigate through large scale environmental space, they make an intriguing animal model for looking at how the brain area necessary for spatial learning, the hippocampus, compares to what we know about the mammalian hippocampus. As such, my research was the first to investigate the connectivity and environmental selectivity of the homing pigeon hippocampus. Found that the avian hippocampus was not only contained a similar trisynaptic pathway, but also contained place cell like,responsive neurons as well as primate like spatial view cells. Because of this series of experiments, I was encouraged to continue to develop this promising species as a model for human diseases affecting the hippocampus.

a.     Hough, G.E., Pang, K.C.H., & Bingman, V.P. (2002).  Intrahippocampal connections in the pigeon (Columba livia) as revealed by stimulation evoked field potentials.  Journal of Comparative Neurology, 452, 297-309.

b.     Kahn, M.C.*, Hough, G.E., TenEyck, G.R., & Bingman, V.P. (2003).  Internal connectivity of the homing pigeon (Columba livia) hippocampal formation: An anterograde and retrograde tracer study.  Journal of Comparative Neurology, 459, 127-141

c.     Hough G.E. & Bingman V.P.  (2004).  Spatial response properties of homing pigeon hippocampal neurons: correlations with goal locations, movement between goals, and environmental context in a radial-arm arena.  Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 190, 1047-1062. 

d.     Bingman, V.P., Gagliardo, A., Hough, G.E., Ioalé, P., Kahn, M.C.*, & Siegel, J.J.*  (2005).  The avian hippocampus, homing in pigeons and the memory representation of large-scale space.  Journal of Integrative and Comparative Biology, 45, 555-564.

e.     Hough, G.E., &  Bingman, V.P. (2008). Rotation of Visual Landmark Cues Influences the Spatial Response Profile of Hippocampal Neurons in Freely-moving Homing Pigeons.  Behavioral Brain Research, 187, 473-477.

3.     Contributed to a complete revision of the anatomical terms in the avian brain. Because of my work in homing pigeon neuroanatomy and neurophysiology, as well as my prior work in songbirds, I was invited to participate in the Avian Brain Nomenclature Forum, a consortium of scientists dedicated to updating the anatomical terminology of the avian brain, updating terms to reflect advances in developmental biology, cellular biology, and physiological studies. I contributed to numerous discussions regarding the homologies between the avian and mammalian brain, which led to several high impact publications as a result of the forum.

a.     Reiner, A., Perkel, D.J., Bruce, L., Butler, A.B., Csillag, A., Kuenzel, W., Medina, L., Paxinos, G., Shimizu, T., Striedter, G.F., Wild, M., Ball, G.F., Durand, S., Güntürkün, O., Lee, D.W., Mello, C.V., Powers, A., White, S.A., Hough, G., Kubikova, L., Smulders, T.V., Wada, K., Dugas-Ford, J., Husband, S., Yamamoto, K., Yu, J., Siang C., & Jarvis, E.D.  (2004). Revised nomenclature for avian telencephalon and some related brainstem nuclei.  Journal of Comparative Neurology, 473, 377-414. [Impact factor: 3.8]

b.     Jarvis, E.D., Güntürkün, O., Bruce, L., Csillag, A., Karten, H., Kuenzel, W., Medina, L., Paxinos, G., Perkel, D.J., Shimizu, T., Striedter, G.F., Wild, M., Ball, G.F., Dugas-Ford, J., Durand, S., Hough, G., Husband, S., Kubikova, L., Lee, D.W., Mello, C.V., Powers, A., Siang, C., Smulders, T.V., Wada, K., White, S.A., Yamamoto, K., Yu, J., Reiner, A., & Butler, A.B.  (2005). Avian brains and a new understanding of vertebrate brain evolution.  Nature Reviews: Neuroscience, 6, 151-159.

4.     The first to demonstrate age-related declines in spatial working memory in birds. My most recent work has been the result of an active collaboration between my former postdoctoral mentor and my undergraduate student. Vincent Coppola and I were the first to investigate the changes in working memory across the lifespan of homing pigeons, which led to the first publication demonstrating a working memory decline in age pigeons. This line of research is in its infancy, but promises to not only expand our knowledge of the effects of aging on the brain, but assist in developing new treatments to detect and remediate age related declines in working memory in humans.

a.     Coppola, V.J.*, Hough, G.E., & Bingman, V.P. (2014). Age-related spatial working memory deficits in homing pigeons (Columba livia). Behavioral Neuroscience, 128(6), 666-675.

.