Modeling developmental spiking behavior driven by ionic current dynamics of mouse and human inner hair cells using a...

Hearing loss (HL) is the third leading cause of years lived with disability worldwide, underscoring the critical need for comprehensive research to unravel the developmental mechanisms that shape auditory function. This work presents a biologically grounded yet computationally efficient model of the inner hair cell (IHC) maturation in the mammalian (Mouse and Human) cochlea replicating the temporal dynamics of spiking suppression along with membrane behaviour accurately. A hybrid modeling framework combining the spiking dynamics of the modified Izhikevich model with bio-physically inspired ionic currents is analysed in this study. The proposed model particularly emphasizes on the significance of calcium-induced potassium currents ([Formula: see text]) which are critical for early developmental excitability. The current study focuses on neonatal mice, reproducing key features of IHC electrophysiology which includes spontaneous action potential (AP) firing at postnatal day 7 (P7) and generation of graded action potentials by day 14(P14) and day 21(P21) stages. The model is further extended to human fetal IHCs at neonatal, mid-mature and adult stages. Unlike in rodents, human IHCs undergo significant maturation inside utero. Furthermore, the results from the current work aligns closely with available in vitro electro-physiological data, membrane potential profiles, intracellular calcium transients and delayed rectifier potassium currents. The proposed framework enables the study of auditory encoding development which may be used to mimic congenital hearing loss(HL) and guide the creation of auditory prostheses.