2021 Seminars
September 2020
| HRC Seminar with Kamal Sen | September 17th |
Kamal Sen, Boston Univeristy
Title: Searching for cortical circuits underlying complex scene analysis
Abstract: This talk will discuss computational models of cortical circuits underlying auditory scene analysis, and some recent experiments in the mouse auditory cortex (in collaboration with Xue Han’s laboratory) employing cell type specific optogenetic perturbations.
| HRC Seminar with Sam Mathias | September 24th |
Sam Mathias, Boston Children’s Hospital
Title: Genetics of solving the cocktail-party problem
Abstract: This talk will present preliminary data from the ongoing Imaging Genomics of the Aging Brain study. We will discuss the roles of genetic and environmental factors on pure-tone hearing thresholds as well as speech-reception thresholds in a “cocktail-party” listening task.
October 2020
| HRC Seminar with Oded Ghitza | October 1st |
Oded Ghitza, Boston University
Title: Acoustic-driven oscillators as cortical pacemaker
Abstract: Oscillation-based models of speech perception postulate a cortical computational principle by which decoding is performed within a window structure derived by a segmentation process. Segmentation of syllable-size chunks is realized by a θ oscillator locked to the input syllabic rate, and segmentation of phrase-long chunks is realized by a δ oscillator locked to the acoustic prosodic structure. In this talk I will propose that from a functional viewpoint, the scaffold for the speech decoding process – through parsing – is an acoustic determinant. Whether oscillation driven or not, the decoding process is paced by a hierarchical cortical clock, realized by oscillators locked to the input rhythm in multiple Newtonian-time scales, keeping the decoding process in sync with the linguistic information flow. Only if such a lockstep is secured can reliable decoding proceed.
| HRC Seminar with Yonghee Oh | October 22nd |
Yonghee Oh, University of Florida
Title: Interaction between voice-gender difference and spatial separation in release from masking in multi-talker listening environments.
Abstract: Voice-gender difference and spatial separation between talkers are important cues for speech segregation in multi-talker listening environments. The goal of the current research series is to understand the interactions of these two cues in order to investigate how they influence masking release in hearing-impaired listeners with hearing-aid and/or cochlear implant devices. Further, a possible factor to explain individual differences in the masking release performance is explored.
| HRC Seminar with Tamar Regev | October 29th |
Tamar Regev, Massachusetts Institute of Technology
Title: Context sensitivity across multiple time scales with a flexible frequency bandwidth
Abstract: Everyday auditory streams are complex, including spectro-temporal content that varies at multiple timescales. Using EEG, we investigated the sensitivity of human auditory cortex to the content of past stimulation in unattended sequences of equiprobable tones. In 3 experiments including 82 participants overall, we found that neural responses measured at different latencies after stimulus onset were sensitive to frequency intervals computed over distinct timescales. Importantly, early responses were sensitive to a longer history of stimulation than later responses. To account for these results, we tested a model consisting of neural populations with frequency-specific but broad tuning that undergo adaptation with exponential recovery. We found that the coexistence of neural populations with distinct recovery rates can explain our results. Furthermore, the adaptation bandwidth of these populations depended on spectral context—it was wider when the stimulation sequence had a wider frequency range. Our results provide electrophysiological evidence as well as a possible mechanistic explanation for dynamic and multiscale context-dependent auditory processing in the human cortex.
November 2020
| HRC Seminar with Julie Arenburg | November 5th |
Julie Arenburg, Massachusetts Eye and Ear Infirmary
Title: Understanding the variability in speech perception performance among individuals with cochlear implants
Abstract: Speech perception scores are highly variable among individuals who have severe-to-profound hearing loss and are fit with cochlear implants. A contributing factor to the variability is the effectiveness with which each cochlear implant electrode activates the target auditory neurons, referred to as the electrode-neuron interface. The role of the electrode-neuron interface and more central factors will be discussed with a special emphasis of how these factors compare between children and adults with cochlear implants.
| HRC Seminar with Malinda McPherson | November 12th |
Malinda McPherson, Harvard University
Title: Efficient and noise-robust representations of sound
Abstract: Some of the most important sounds humans hear, including speech and music, are harmonic, with frequencies related by integer ratios. In this talk I will re-examine the role of harmonic sounds in hearing. I will present evidence that human sensitivity to harmonic frequency structure increases the robustness of hearing to noise, and helps listeners compress sounds into compact representations that aid memory. The results suggest that representations of harmonic sounds are fundamental to auditory perception and cognition, and clarify their importance in music.
| HRC Seminar with Elizabeth McCullagh | November 19th |
Elizabeth McCullagh, Oklahoma State University
Title: New insights into binaural hearing from animal models of Fragile X syndrome
Abstract: How are sounds located in the environment? Dr. McCullagh will talk about her past and current research on brainstem level sound processing in a genetic form of autism, FXS. Additionally, she will talk about new work in her lab using a comparative approach to understand hearing with two ears.
