What are the neural mechanisms for coding complex sounds?

 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?

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 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.




Newly Published!

  • MacLeod, K.M., Pandya, S. (2022) Expression and Neurotransmitter Association of the Synaptic Calcium Sensor Synaptotagmin in the Avian Auditory Brain Stem. JARO  doi: 10.1007/s10162-022-00863-1
  • Baldassano JF, MacLeod KM. (2022) Kv1 channels regulate variations in spike patterning and temporal reliability in the avian cochlear nucleus angularis. J Neurophysiol. 2022 Jan 1;127(1):116-129. doi: 10.1152/jn.00460.2021 Epub 2021 Nov 24. PMID: 34817286; PMCID: PMC8742726.

    Preprint available on BioRxiv: 

    1. MacLeod, K.M., Eisenbach, S. L., and Soueidan, S.E. (2020) Presynaptic modulation of inhibitory synaptic feedback in the avian cochlear nucleus angularis. BioRxiv https://doi.org/10.1101/619783