Research
The pallid bat (Antrozous pallidus) is a gleaning bat in the southwestern US. It listens to prey-generated noise to localize and hunt terrestrial prey such as crickets and scorpions while reserving echolocation for obstacle avoidance. For echolocation, the pallid bat uses 60-30 kHz downward frequency modulated sweeps. For prey localization it listens to noise transients in the 5-30 kHz range. The auditory system of the pallid bat is organized as two parallel pathways from the inferior colliculus to thalamus to auditory cortex. The echolocation pathway serves as a model to understand mechanisms and development of spectrotemporal processing and the noise-pathway serves as a model to study cortical mechanisms of sound localization. More recently we have begun to examine mechanisms of scorpion venom resistance in the pallid bat.
We study cortical processing in various mouse models to take advantage of genetic engineering tools. The second main project in the lab is to understand mechanisms underlying presbycusis-related declines in spectrotemporal processing. Presbycusis (age-related hearing loss) is the most prevalent hearing disability in humans. Speech recognition deficits, social isolation and cognitive declines are associated with presbycusis. One key deficit is a decline in processing of fast spectrotemporal cues present in speech, but the neural correlates are unclear. We study cortical processing of FM and AM sounds in quiet and in noise in the C57bl/6 mice (undergoes accelerated age-related hearing loss), C57.cast mice (same strain as C57bl6, but without the rapid hearing loss) and CBA mice (without rapid hearing loss) to determine relative contributions of aging and hearing loss to presbycusis-related decline in cortical processing.
The third major project in the lab is to understand mechanisms of auditory processing deficits in Fragile X Syndrome (FXS). FXS is a leading cause of inherited intellectual disability and a known genetic cause of autism spectrum disorders. In humans with FXS, strunctural and functional studies reveal auditory processing disorders with auditory hypersensitivity being a prominent phenotype. Auditory hypersensitivity is also found in the Fmr1 knock-out mice, the mouse model of FXS. We are exploring the cortical mechanisms that underlie this deficit, and are investigating available and novel drug targets in pre-clinical models with auditory processing as outcome measures. The rationale is that mechanisms of basic sensory processing are relatively easier to understand compared to more complex behaviors such as social interactions, anxiety, etc.
Funding
National Science Foundation CAREER award
National Institutes of Health
USARMY/Dept. of Defense