Our whole lives we are made to communicate- sometimes to prove our social abilities, often to convey authority, but maybe above all, we have an inherent need to hear our voice among a mass of billions. We do this by using our hands, our minds, and our language to empower ourselves with a voice. Being a graduate student, I am often asked to share the intricacies of my work with other like-minded individuals. For that, the voice I use is a practiced and trained one, and not the one that evokes the fun that in truth drives my scientific curiosity. So today I communicate to you, for the first time in my real voice, that the breadth of science is too awesome to ignore. Here, I will present to you vignettes of discovery from all facets of science addressing questions of life from diverse perspectives. If it began with a hypothesis and involved an experiment, I will relay to you the conclusions the best I can. And today’s topic, of course, is communication.
Birds at the bar
This first story is drawn from a classic model organism for understanding animal communication – the songbird. Scientists have taken advantage of the similarities between bird and human neural systems to simplify the innate complexities associated with neural plasticity, social courtship behavior, and vocal learning and memory. The star of the Passeriformes, the Zebra Finch, is a species indigenous to Australia and the second of the birds to have its genome interrogated, sequenced and aligned back together (the first, of course, is the chicken which has aided biologists in understanding evolutionary relationships between classes of animals since 2004). Since then, the bird genome sequencing project that aimed to identify a phylogeny of differentiation between the extinct dinosaur and the diverse collection of flying, feathered fowl that dominate the skies, has set a foundation to understand the molecular intricacies of complex learning behaviors.
Armed with this knowledge, the latest question posed by Oregon scientists trying to gain insight into neural function and vocal communication was one that may apply to many of us: “How does alcohol affect an organism’s ability to communicate?” I have definitely been in a situation where the consumption of alcohol has confused my thoughts, slurred my words and mangled my general ability to get a point across. So what is really happening here? Claudio Mello’s group at the Oregon Health and Science University addressed this question by providing Zebra Finches with water, then juice, followed by either 6.5% alcohol in juice or a juice control. After measuring the blood ethanol content of the finches (a mean of 44mg/dl) and learning the birds actually like the stuff, the researchers measured several attributes of song including rates of song production, acoustics and song stereotypy. It seemed that individual effects of alcohol were quite variable from bird to bird (true for humans too!) but overall, Mello’s group learned that while consumption of alcohol resulted in a negligible decrease in song rate, there was an appreciable increase in entropy and significant decrease in amplitude. Meaning, the birds were slurring their songs! This study defines the paradigms to utilize Zebra Finches to assess the impacts of drinking on neural circuitry and lays a foundation to ask more poignant questions regarding precisely which neurons are involved and which genes are most important for regulating these functions. So, next time you hear your local bird sing with some extra oscillations, you might check to see if your liquor cabinet has been pecked at.
Eels on Meals
Our next story comes from the lab of Kenneth Catania at Vanderbilt University, which utilizes everything from the Star-Nosed Mole to Tentacled Snakes to better understand sensory organs and their impact on brain function. Their most recent work describes a remote control-like mechanism utilized by some fish to capture dinner. Many people may not realize (I sure didn’t) that the electric eel is not actually an eel, but the largest species of a type of knifefish classified in the order Gymnotiformes. (Real eels are elongated fish belonging to the order Anguilliformes.)
Interested in the unique behavior of Eels, Kenneth Catania sought to address the question of how electrical charges affect the prey of these mysterious predators and what he discovered was eelectrifying! (Yes, I like puns, and no, this is not the last one). Charged with the observation that the muscle movement of nearby prey was arrested only milliseconds after high-voltage pulses from the Eel, Kenneth Catania performed a telling experiment. He housed an Eel along with a couple of fish in an aquarium, separated by an electrically permeable barrier and fed the Eel earthworms. When the Eel shocked the earthworms in its quadrant of the aquarium, indeed there was a corresponding muscle contraction in the nearby fish. Further, when he injected one of the two fish with curare (an acetylcholine antagonist), the electrical discharge from the Eel no longer had any effect on this fish whereas the sham-injected fish consistently displayed the characteristic muscle spasm. Because curare inhibits neuromuscular junctions (think poisonous dart frogs) these data suggest that Eels are able to ‘remotely control’ the motor neurons of nearby prey. Therefore, these creatures can immobilize their prey by emitting a high-voltage electrical pulse as well as unmask hidden prey by causing them to twitch! This fascinating adaptation sheds new light on the mechanism by which the Electric Eel communicates with its ill-fated prey, along with the terrifying possibility that an eel is making me write this…
Dog-Human communication
Our final tale explores the communicative relationship between humans and their pets – specifically dogs (I heard that scoff, ailurophile!). It’s no secret that this generation has fallen frenzy to the affections of furry friends beyond any generation that has preceded it, prompting Victoria Ratcliffe and David Reby from the University of Sussex to investigate the intricacies of language between two very disparate species. The duo presented dogs with various tones and speech while simultaneously monitoring processing of that sound by observation of which way the dogs turned their head. Tones are presented to the animal from both sides and a turn to the left in response to the sound means the processing occurred in the right hemisphere while a turn to the right suggests left hemisphere dominance. Surprisingly, when the dogs were presented with a familiar command, there was an astounding 80% right-head turn bias, suggesting that familiar cues and language are processed by the left hemisphere. Presented with the same command but altered such that only the emotional qualities of the tone were recognizable, the dogs tended to turn to their left more often – engaging the right hemisphere. So what does this mean? Dog’s process language similarly to their human friends! It’s almost not surprising as the brain is fairly conserved through evolution; yet what is surprising is that language is uniquely a human trait. While it is not clear how the canines understand language, it is clear that they process it in a way similar to us. So next time you decide to reveal your innermost thoughts to the adorable puppy on your lap, remember, she could be judging you.
This wraps up my first post. I hope a story of communicating love, one of communicating fear and a final tale on communication between friends has found you thinking about the natural world around you. Hope you all get a chance to communicate what you learned!
References
- K. Catania, The shocking predatory strike of the electric eel. Science 346, 1231 (Dec 5, 2014).
- V. F. Ratcliffe, D. Reby, Orienting asymmetries in dogs’ responses to different communicatory components of human speech. Current biology : CB 24, 2908 (Dec 15, 2014).
- C. R. Olson, D. C. Owen, A. E. Ryabinin, C. V. Mello, Drinking songs: alcohol effects on learned song of zebra finches. PloS one 9, e115427 (2014).