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Department of Physiology, Development and Neuroscience

 

University Physiologist Tel: +44 (0)1223 333829, Fax: +44 (0)1223 333840, E-mail: mjm68@cam.ac.uk

 

My research: structure and function of the ear

"Consider the first and last major steps in anatomical construction of the mammalian middle ear - for we know no better or more intriguing story in the evolution of vertebrates" Stephen Jay Gould (1993).

The middle ear apparatus improves the efficiency of sound energy transfer from the air through to the fluid-filled inner ear, which contains the hair cells that will turn vibrations into electrical signals interpretable by the brain. I am interested in how middle and inner ear strucures have evolved in different vertebrate groups, and what we can infer about function from their anatomy.

My research involves examining a wide range of different ears (from museum specimens and even fossils), using techniques such as light microscopy, electron microscopy and micro-CT scanning. I investigate the likely hearing range of the animal in question, in order to answer questions about how hearing is matched to particular acoustical properties of the environment that the animal lives in, and how the ear might have evolved. I have investigated potentially vestigial features of the ear in the enigmatic naked mole-rat (Fig. 1), and the enormously expanded middle ear cavities of certain elephant-shrews (Fig. 2), which improve the detection of airborne sound at the low frequencies that travel best in their desert habitat. I also work on the ears of frogs, including studying the tiny Brazilian pumpkin toadlet (Fig. 3). The part of the ear responsible for high-frequency hearing is undeveloped, which means that it cannot hear its own calls! However, this toadlet shows bright, fluorescent markings under UV light, and we are currently trying to work out why that might be.

Here are some links for further information about what I do:

My research on the ears of mammals

My research on the ears of non-mammalian vertebrates

Podcast interview with The Naked Scientists

My important contribution to understanding the physiology of zombies from Game of Thrones

And have a look at the February 2016 Special Issue of the Journal of Anatomy which I co-edited, which contains a series of papers introducing the structure, function, development and evolution of the ear.

 

My research has been sponsored by the BBSRC and the National Institutes of Health.

 

Fig. 1: Ear structures in the naked mole-rat (see Mason et al., 2016).
Fig. 2: Micro-CT scan of the skull of the extraordinary elephant-shrew Macroscelides. Its middle ear cavities, contained within the swollen regions of the skull which are shaded in red, have a combined volume 30% greater than brain volume. See Mason (2016).
Fig. 3: The pumpkin toadlet Brachycephalus pitanga. This tiny frog cannot hear its own calls, but it does fluoresce under UV light! See Goutte et al. (2019).