Associate Professor Jakob Christensen-Dalsgaard's main interest is the function and evolution of the middle ear and directional hearing, mainly in reptiles, amphibians and birds. Ongoing research is within neuroethology, using neurophysiological techniques (auditory evoked responses and single-cell physiology), psychophysics and biophysics (laser vibrometry) and biorobotics.

Current research areas

Middle ear development

Studies of development are crucial in understanding the evolution of the middle ears. The main current focus of my laboratory is developmental studies in frogs and toads, lizards and birds, combining anatomical, biophysical and neurophysiological techniques (mainly ABR), but in the future also molecular biology.

Directional hearing

Directional hearing in lizards (like geckos) that have strongly coupled eardrums, leading to a highly directional ear. I am presently investigating the neural processing of the directional cues, and our biophysical and neural models have led to biorobotic implementations in sound-localizing robots.

Function (and loss) of the middle ear in frogs, toads and salamanders

Function (and loss) of the middle ear in frogs, toads and salamanders, with investigations of middle ear function and directionality in several frog and toad species. Work on 'earless' toads (that have a non-functional middle ear) in Ecuador and Peru has been done in collaboration with Kim Hoke, Colorado State University, and Molly Womack ( Cornell University), in salamanders with Grace Capshaw (Johns Hopkins University) and Catherine Carr (University of Maryland).

Middle ear adaptations for underwater hearing

Comparative studies of hearing in aquatic frogs (Xenopus laevis), turtles, cormorants and humans in my lab have shown that a modified tympanic ear is very sensitive to underwater sound, largely because of resonance in the enclosed air in the middle ear. We are modelling the response of such ears and also applying these models to extinct species.