Department of Physiology and Biophysics
University of Colorado School of Medicine
RC1 North Tower, P18-7107
Mail Stop 8307
Aurora, CO 80045
Joint Appointment with Department of Otolaryngology
The goal of the work in my lab is to understand the neural mechanisms of auditory perception with particular emphasis on how sources of sounds are localized. Because the peripheral receptors of the ear have no mechanism to directly sense sound location on their own (unlike the topographic organization of the retina), location must be computed at more central levels. This makes sound localization a fascinating neurocomputational problem, particularly from a developmental perspective. Our experiments seek answers to at least four basic questions:
I use a multidisciplinary approach to tackle these questions employing both experimental and theoretical techniques including human and animal psychophysics, extracellular physiology, signal detection and information theory, systems identification techniques, acoustic transfer function measurement and modeling, digital filter design and estimation, acoustic signal design, and physiological systems modeling.
Fig. 1 Illustration of a frontal section through the brainstem showing the ascending pathways through the nuclei of the superior olivary complex that are believed to be responsible for encoding interaural level differences (ILDs). Neurons of the lateral superior olive (LSO) receive bilateral inputs from both ears. The input from the ipsilateral ear via the spherical bushy cells (SBCs) is excitatory (open symbols) but the input from the contralateral ear via the globular bushy cells (GBCs) of the contralateral anteroventral cochlear nucleus (AVCN) is inhibitory (filled symbols) due to the additional synapse in the ipsilateral medial nucleus of the trapezoid body (MNTB). The interplay of the ipsilateral excitation and contralateral inhibition confers on LSO neurons sensitivity to ILDs. LSO neurons send excitatory projections to the contralateral inferior colliculus (IC) and dorsal nucleus of the lateral lemniscus (DNLL) and inhibitory projections (not shown) to the ipsilateral IC and DNLL. The color bar and shading indicates the tonotopic organization and shows that the neurons comprising the MNTB and LSO are sensitive to predominantly high frequency sounds.
Peacock J, Spellmen GM, Greene NT and Tollin DJ (2020) Scaling of the avian middle ear, Hearing Research 395, https://doi.org/10.1016/j.heares.2020.108017 (image from this publication on the cover of this issue Hearing Research).
Peacock J, Spellmen GM, Tollin DJ and Greene NT (2020) A comparative study of avian middle ear mechanics, Hearing Research 395, https://doi.org/10.1016/j.heares.2020.108043
Brown AD, Anbuhl KL, Gilmer JI and Tollin DJ (2019) Between-ear sound frequency disparity modulates a brainstem biomarker of binaural hearing, Journal of Neurophysiology, 122:1110-1122.
Brown AD, Benichoux V, Jones HG, Anbuhl KL and Tollin DJ (2018) Spatial variation in signal and sensory precision both constrain auditory acuity at high frequencies, Hearing Research 370:65-73.
Benichoux V, Ferber AT, Hunt SD, Hughes EG and Tollin DJ (2018) Across species ‘natural ablation’ reveals the brainstem source of a non-invasive biomarker of binaural hearing, Journal of Neuroscience, 38:1211-18.
Benichoux V and Tollin DJ (2018) These are not the neurons you are looking for. eLife Jul 27;7. pii: e39244.
Greene NT, Anbuhl KL, Ferber AT, DeGuzman M, Allen PD and Tollin DJ (2018) Spatial hearing ability of the pigmented guinea pig (Cavia porcellus): minimum audible angle and spatial release from masking in azimuth, Hearing Research 365:62-76.
Benichoux V, Brown AD, Anbuhl KL and Tollin DJ (2017) Representation of multidimensional stimuli: quantifying the most informative stimulus dimension from neural responses, Journal of Neuroscience, 37:7332-7346.
Brown, AD and Tollin DJ (2016) Slow temporal integration enables robust neural coding and perception of a cue to sound source location, Journal of Neuroscience 36:9908-9921.
Ashida G, Kretzberg J, Tollin DJ (2016) Roles for coincidence detection in coding amplitude-modulated sounds. PLoS Comput Biol 12 (6): e1004997. doi:10.1371/journal.pcbi.1004997
Laumen G, Ferber AT, Klump GM and Tollin DJ (2016). The physiological basis and clinical use of the binaural interaction component of the auditory brainstem response, Ear & Hearing 37:276–290
Jones HG, Brown AD, Koka K, Thornton JL and Tollin DJ (2015) Sound frequency-invariant neural coding of a frequency-dependent cue to sound source location. J Neurophysiol 114:531-539.
Brown AD, Stecker GC and Tollin DJ (2015) The precedence effect in sound localization, J. Assoc. Res. Otolaryngol (JARO), 16:1-28.
Bierman HS, Thornton JL, Jones HG, Koka K, Young BA, Carr CE and Tollin DJ (2014) Biophysics of directional hearing in the American Alligator (Alligator mississippiensis), J Exp Biol 217:1094-1107. (Top 5 most read article in the Journal of Experimental Biology in 2014)
Sammeth C, Greene NT, Brown AD and Tollin DJ (2020, in press) Normative Study of the Binaural Interaction Component of the Human Auditory Brainstem Response as a Function of Interaural Time Differences, Ear and Hearing.
Banakis-Hartl RM, Brown AD, Benichoux V, Dondzillo A, Greene NT and Tollin DJ (2019) Establishing an Animal Model of Single-Sided Deafness in Chinchilla lanigera, Otolaryngology-Head and Neck Surgery 161(6):1004-1011
Peacock J, Alhussaini MA, Greene NT, Tollin DJ (2018) Intracochlear pressure in response to high intensity, low frequency sounds in chinchilla, Hearing Research 367:213-222.
Greene NT, Alhussaini MA, Easter J, Argo T, Walilko T and Tollin DJ (2018) Intracochlear pressure measurements during acoustic shock wave exposure, Hearing Research 365:149-164.
Banakis-Hartl RM, Greene NT, Jenkins HA, Cass SP and Tollin DJ (2018) Lateral semi-circular canal pressures during cochlear implant electrode insertion: A possible mechanism for postoperative vestibular loss, Otol Neurotol 39:755-764.
Farrell N, Banakis-Hartl RM, Benichoux V, Brown AD, Cass SP and Tollin DJ (2017) Effects of time and level difference inputs to bilaterally placed bone-conduction systems on cochlear input, Otol Neurotol. 38:1476-1483.
Greene NT, Jenkins HA, Tollin DJ, and Easter JR (2017) Stapes displacement and intracochlear pressure in response to very high level, low frequency sounds, Hear Res 348:16-30.
Maxwell AK, Banakis-Hartl RM, Greene NT, Benichoux V, Mattingly JK, Cass SP and Tollin DJ (2017) Investigating vestibular blast injury: Semicircular canal pressure changes during high-intensity acoustic stimulation, Otol Neurotol. 38:1043-1051.