Estrada, R. | bioRxiv Science

bioRxiv2017

Elucidation of dose-dependent transcriptional events immediately following ionizing radiation exposure

Long duration space missions expose astronauts to ionizing radiation events associated with highly energetic and charged heavy particles. Such exposure can result in chromosomal aberrations increasing the likelihood of the development of cancer. Early detection and mitigation of these events is critical in providing positive outcomes. In order to aid in the development of portable devices used to measure radiation exposure, we constructed a genome-wide screen to detect transcriptional changes in peripheral blood lymphocytes shortly after (approximately 1 hour) radiation exposure at low (0.3 Gy), medium (1.5 Gy) and high (3.0 Gy) doses compared to control (0.0 Gy) using Affymetrix(R) Human Gene 1.0 ST v1 microarrays. Our results indicate a number of sensitive and specific transcriptional profiles induced by radiation exposure that can potentially be implemented as biomarkers for radiation exposure as well as dose effect. For overall immediate radiation exposure, KDELC1, MRPS30, RARS, and HEXIM1 were determined to be effective biomarkers while PRDM9, CHST4, and SLC26A10 were determined to be biomarkers specific to 0.3 Gy exposure; RPH, CCDC96, WDYHV1, and IFNA16 were identified for 1.5 Gy exposure; and CWC15, CHCHD7, and DNAAF2 were determined to be sensitive and specific to 3.0 Gy exposure. The resulting raw and analyzed data are publicly available through NCBI's Gene Expression Ominibus via accession GSE64375.

bioinformatics↗

bioRxiv2017

Evidence for time division multiplexing of multiple simultaneous itemsin a sensory coding bottleneck

How the brain preserves information about multiple simultaneous items is poorly understood. We report that single neurons can represent multiple different stimuli by interleaving different signals across time. We record single units in an auditory region, the inferior colliculus, while monkeys localize 1 or 2 simultaneous sounds. During dual-sound trials, we find that some neurons fluctuate between firing rates observed for each single sound, either on a whole-trial or on a sub-trial timescale. These fluctuations are correlated in pairs of neurons, can be predicted by the state of local field potentials prior to sound onset, and, in one monkey, can predict which sound will be reported first. We find corroborating evidence of fluctuating activity patterns in a separate data set involving responses of inferotemporal cortex neurons to multiple visual stimuli. Alternation between activity patterns corresponding to each of multiple items may therefore be a general strategy to enhance the brain processing capacity, potentially linking such disparate phenomena as variable neural firing, neural oscillations, and limits in attentional/memory capacity.

neuroscience↗