Biology subjects

Dwyer, N.

Publications and source records attributed to Dwyer, N..

2 recordsLinked to original sources

bioRxiv2021

Dorsolateral prefrontal cortex supports speech perception in listeners with cochlear implants

Cochlear implants are neuroprosthetic devices that can restore hearing in people with severe to profound hearing loss by electrically stimulating the auditory nerve. Because of physical limitations on the precision of this stimulation, the acoustic information delivered by a cochlear implant does not convey the same level of acoustic detail as that conveyed by normal hearing. As a result, speech understanding in listeners with cochlear implants is typically poorer and more effortful than in listeners with normal hearing. The brain networks supporting speech understanding in listeners with cochlear implants are not well understood, partly due to difficulties obtaining functional neuroimaging data in this population. In the current study, we assessed the brain regions supporting spoken word understanding in adult listeners with right unilateral cochlear implants (n=20) and matched controls (n=18) using high-density diffuse optical tomography (HD-DOT), a quiet and non-invasive imaging modality with spatial resolution comparable to that of functional MRI. We found that while listening to spoken words in quiet, listeners with cochlear implants showed greater activity in left prefrontal cortex than listeners with normal hearing, specifically in a region engaged in a separate spatial working memory task. These results suggest that listeners with cochlear implants require greater cognitive processing during speech understanding than listeners with normal hearing, supported by compensatory recruitment of left prefrontal cortex.

neuroscience↗

bioRxiv2019

Cytokinetic furrowing and abscission dynamics during brain development revealed by live imaging

McNeely et al. quantitatively analyze polarized cytokinetic furrow ingression and abscission in mouse neuroepithelium by live imaging. The findings show important differences from HeLa cells, and suggest abscission timing and midbody release may be developmentally regulated, to influence daughter cell fate during brain growth. AbstractWhile mechanisms of cytokinesis have been identified in single cell models, the spatial and temporal regulation in developing tissues is less understood. Here we compare cytokinetic furrowing and abscission in mouse neuroepithelial stem cells (NESCs) at different developmental stages and in a cytokinesis mutant, including imaging abscission dynamics in a polarized epithelium for the first time. We find that asymmetric furrows of NESCs ingress at a constant but slow rate, and form the midbody at the apical membrane. Usually, bilateral abscission on each midbody flank releases the midbody remnant extracellularly. Interestingly, midbody remnants are more associated with early proliferative divisions. Unexpectedly, in the microcephalic Kif20b mutant, abscission is accelerated and occurs when the midbody is wider. The daughter cells of mutant NESCs show increased cell cycle exit that is p53-independent. We suggest that abscission mechanisms are developmentally regulated. These results provide significant insight into adaptations of a fundamental cell biological process required for proper brain growth.

developmental biology↗