Lila Urogdy
Research Mentor(s): Michael Roberts
Mentor Department: Otolaryngology-Head and Neck Surgery
Authors: Lila Urogdy, Elie Huez, Michael Roberts
Session: Session 5 (2:00pm – 2:50pm)
Presentation Type: Poster 14
Abstract
The ability to perceive and process sound is an essential function for the survival of many species, but many of the neural mechanisms involved in auditory computations remain unknown. The inferior colliculus (IC) is a midbrain integration hub in the central auditory system. Morphologically, neurons in the central nucleus of the IC can be divided into two classes: intra-lamina disc-shaped neurons and trans-laminar stellate-shaped neurons. Molecularly, IC neurons can be divided into excitatory (glutamatergic) and inhibitory (GABAergic) classes. To further subdivide these IC neuron classes, molecular markers can be used to target individual IC neuron types. Recently, we have shown that secreted phosphoprotein 1 (SPP1) and prodynorphin (PDYN) each represent a novel molecular marker for excitatory IC neuron subpopulations, but their respective morphological classes remain unknown. We hypothesize that SPP1 represents a class of stellate-shaped IC neurons and that PDYN represents a heterogeneous class of disc- and stellate-shaped IC neurons. To investigate the morphologies of these two neuron classes, we filled SPP1 and PDYN neurons with biocytin through a recording electrode in a previous experiment. Laser-scanning confocal images of SSP1 and PDYN biocytin-filled neurons were taken and reconstructed in 3D with Neurolucida 360. Our data as of now suggest that SPP1 IC neurons represent trans-laminar stellate-shaped morphologies. In contrast, PDYN IC neurons represent a heterogeneous population of disc-shaped cells in the central nucleus of the IC and stellate-shaped cells in the cortex regions of the IC. Identifying the morphologies of PDYN and SPP1 IC neuronal subpopulations provides a foundation for future studies to investigate the local circuitry of PDYN and SPP1 in the IC.
