What are the neural mechanisms for coding complex sounds?

Coming up: Presentations at the 43rd Annual Meeting of the Society for Neuroscience in San Diego, Nov 7-13th:

 

* Tuesday AM session, Nov 12th 548.03/PP16 Presynaptic release properties show target-specific regulation at auditory nerve terminals in avain cochlear nuclei. Ahn, J. and MacLeod, K.M.

* Tuesday PM session, Nov 12th 615.21/F10 Neurons in bat entorhinal cortex show an inverse gradient of resonance frequency compared to neurons in rat entorhinal cortex. Heys, J.G., MacLeod, K.M., Moss, C.F., and Hasselmo, M.E.

 

We investigate fundamental aspects of auditiory physiology using whole-cell patch-clamp recordings from brain slices, in vivo electrophysiology, quantitive modeling of synaptic plasticity and biophysical membrane properties, and immunohistochemical techniques. Our model system is the avian auditory brainstem.   All information about an auditory scene combines to a single sound pressure waveform impinging on the eardrum. These vibrations are encoded as spiking activity in auditory nerve, which in turn projects to the cochlear nuclei in the brain stem. Our driving question is: how does the brain interpret this activity as the complex auditory world around us?  And how do we do this especially when there are multiple overlapping sound sources?

 

Our focus is understanding how intensity signals are encoded to determine sound location and sound identity. At the level of the cochlear nucleus, different types of information are extracted by using distinct synaptic and cellular specializations that decode the nerve inputs.  How are timing and intensity cues are extracted at the auditory nerve to cochlear nucleus synapse? How might short-term synaptic plasticity contribute to encoding sound envelope or overall level? What role do the various intrinsic firing properties of different cell types have in encoding sound envelopes? How is the information about intensity passed along by ascending circuits?

 

We have a number of ongoing projects related to these questions. More details can be found by clicking the Research tab.

 

Research highlight: "Bat and Rat Neurons Differ in Theta-Frequency Resonance Despite Similar Coding of Space", Heys, MacLeod, Moss and Hasselmo, 19 April 2013 issue of Science, v340(6130): 363-7. In this paper we investigated the resonance properties of entorhinal cortical neurons involved in spatial navigation by echolocation. First ever publication of data from bat brain slices! Congrats to Cindy Moss here at UMCP and our collaborators from Boston University Jim Heys and Michael Hasselmo.

 

See also Perspective by Barry & Doeller and in the same issue, Yartsev & Ulanovsky recorded place cells in 3D in flying bats!

 

 

--->link to College of Computer, Mathematical and Natural Sciences News highlight

News

  • November 2013: We're off to Society for Neuroscience Meeting in San Diego!
  • April 2013: Science article on bat entorhinal cortical neurons is out!
  • Postdoctoral fellow opening available - more info
  • March 2013: Congrats to Shelley on her new position!
  • March 2013: We welcome new undergrad Melissa to the lab!
  • Feb 2013: Jheeyae presents her work at ARO in Baltimore.
  • Jan 2013: Lecture & visit JHU Center for Hearing & Balance
  • July 2012: Lauren & Arslaan's work (Kreeger et al. 2012) is published in the Journal of Neurophysiology!