Search bioRxivSearch

Biology subjects

Zak, J.

Publications and source records attributed to Zak, J..

2 recordsLinked to original sources

HTX: a tool for the exploration and visualization of high-throughput image assays

High-throughput screening (HTS) techniques have enabled large scale image-based studies, but extracting biological insights from the imaging data in an exploratory setting remains a challenge. Existing packages for this task either require expert annotations, which can bias the outcome of the study, or are completely unsupervised, failing to leverage the information present in the assay design. We present HTX, an interactive tool to aid in the exploration of large microscopy data sets by allowing the visualization of entire image-based assays according to visual similarities between the samples in an intuitive and navigable manner. Underlying HTX are a collection of novel algorithmic techniques for deep texture descriptor learning, 2D data visualization, adversarial suppression of batch effects, and backprop-based image saliency estimation.\n\nWe demonstrate that HTX can exploit the screen meta-data in order to learn screen-specific image descriptors, which are then used to quantify the visual similarity between samples in the assay. Given these similarities and the different visualization resources of HTX, it is shown that screens of small-molecule libraries on cell data can be easily explored, reproducing the results of previous studies where highly-specific domain knowledge was required.

bioinformatics

Antagonism in olfactory receptor neurons and its implications for the perception of odor mixtures

Natural environments feature mixtures of odorants of diverse quantities, qualities and complexities. Olfactory receptor neurons (ORNs) are the first layer in the sensory pathway and transmit the olfactory signal to higher regions of the brain. Yet, the response of ORNs to mixtures is strongly non-additive, and exhibits antagonistic interactions among odorants. Here, we model the processing of mixtures by mammalian ORNs, focusing on the role of inhibitory mechanisms. Theoretically predicted response curves capture experimentally determined glomerular responses imaged by a calcium indicator expressed in ORNs of live, breathing mice. Antagonism leads to an effective \"normalization\" of the ensemble glomerular response, which arises from a novel mechanism involving the distinct statistical properties of receptor binding and activation, without any recurrent neuronal circuitry. Normalization allows our encoding model to outperform noninteracting models in odor discrimination tasks, and to explain several psychophysical experiments in humans.

neuroscience