With fine representations of neurons crucial for hearing – the bushy cells – the winner of the 2023 Neuroscience cover competition captures the beauty of these neurons and the natural changes that occur over time. Featured in Neuroscience issue 514, the cover image was part of the study conducted by Dr. Ruili Xie, an associate professor at the Department of Otolaryngology at The Ohio State University and leader of the Auditory Neuroscience Lab. In this interview, he explains the research behind the winning cover image, which was prepared in collaboration with Dr. Meijian Wang and Dr. Chuangeng Zhang, who were postdoctoral researchers at the time of the study, as well as with Dr. Shengyin Lin, who continues to work in the lab as a research associate.
What is your research about?
We are interested in studying how sound information is processed in the auditory nervous system and the underlying mechanisms of age-related hearing loss (ARHL). Our focus has been in the cochlear nucleus, which is the first neural station of the central auditory nervous system that receives all sound information from the auditory nerve.
> Dr. Ruili Xie
What was the goal and the hypothesis of the study published in Neuroscience?
Sound information from the ear is transmitted by the auditory nerve to neurons in the cochlear nucleus, and then distributed throughout the auditory nervous system for processing and ultimately sound perception. One principal neuron in the cochlear nucleus is the bushy cell, which is critical for hearing and has been studied for decades in the auditory field. However, some fundamental questions remain unclear, including how synapses of the auditory nerve innervate bushy cells and how bushy cells change in morphology and physiology during aging, which are processes that may underlie ARHL. The goals of this study published in Neuroscience, therefore, were to characterize the morphological changes of bushy cells and their innervating synapses during aging, and elucidate the mechanisms of ARHL in the cochlear nucleus. Our hypothesis was that the morphology and physiology of bushy cells deteriorate during aging, which contributes to compromised auditory function in ARHL.
What were your main findings?
In agreement with our hypothesis, we found that the dendrites of bushy cells degenerate with age, resulting in reduced complexity of the dendritic arborization and altered innervation pattern of auditory nerve synapses. These morphological changes are expected to underlie the reduced auditory input to the brain and impaired sound perception in the elderly.
Dr. Xie and his team. From left to right: Dr. Benjamin Seicol, Dr. Chuangeng Zhang, Dr. Shengyin Lin, Dr. Meijian Wang, and Dr. Xie.
What is still unclear and requires further investigation?
Bushy cells receive auditory nerve input via the large endbulb of Held synapses onto their soma and also small bouton synapses on their distinctive dendrites. These neurons specialize in processing temporal information of sound, which is believed to be mainly encoded by the somatic endbulb of Held synapses. The exact functions of the ‘bush-like’ dendrites in bushy cells and their small dendritic synapses remain unsolved. It is also unclear how dendritic degeneration and altered synaptic innervation demonstrated in this study influence the physiological function of bushy cells during aging, and ultimately how such changes contribute to ARHL.
What does the issue 514 cover image represent?
The cover image depicts nine representative bushy cells from young (left column) and old (right column) mice that were recorded in brain slices, dye-filled, imaged, and reconstructed. The image gives a visual demonstration of morphological changes in bushy cells during aging.
How was your experience with publishing in Neuroscience?
The whole process of publishing in Neuroscience was quick and smooth. Neuroscience is a solid journal in the field and one of my favorite scientific journals. We like to publish in Neuroscience and will continue to submit our future studies to the journal.
About Neuroscience
Established in 1976, Neuroscience is the flagship journal of IBRO. The journal features papers describing the results of original research on any aspect of the scientific study of the nervous system. Papers of any length are considered for publication provided that they report significant, new, and carefully confirmed findings with full experimental details. Together with IBRO Neuroscience Reports, IBRO’s open access journal, Neuroscience plays a crucial role in supporting the organization’s global neuroscience activities, as proceeds from both journals support more than 90% of IBRO’s initiatives.