PLOS Biology: New Articles
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How do mammals convert dynamic odor information into neural maps for landscape navigation?
by Anantu Sunil, Olivia Pedroncini, Andreas T. Schaefer, Tobias Ackels
Odors are transported by seemingly chaotic plumes, whose spatiotemporal structure contains rich information about space, with olfaction serving as a gateway for obtaining and processing this spatial information. Beyond tracking odors, olfaction provides localization and chemical communication cues for detecting conspecifics and predators, and linking external environments to internal cognitive maps. In this Essay, we discuss recent physiological, behavioral, and methodological advancements in mammalian olfactory research to present our current understanding of how olfaction can be used to navigate the environment. We also examine potential neural mechanisms that might convert dynamic olfactory inputs into environmental maps along this axis. Finally, we consider technological applications of odor dynamics for developing bio-inspired sensor technologies, robotics, and computational models. By shedding light on the principles underlying the processing of odor dynamics, olfactory research will pave the way for innovative solutions that bridge the gap between biology and technology, enriching our understanding of the natural world. -
Stochastic models allow improved inference of microbiome interactions from time series data
by Román Zapién-Campos, Florence Bansept, Arne Traulsen
How can we figure out how the different microbes interact within microbiomes? To combine theoretical models and experimental data, we often fit a deterministic model for the mean dynamics of a system to averaged data. However, in the averaging procedure a lot of information from the data is lost—and a deterministic model may be a poor representation of a stochastic reality. Here, we develop an inference method for microbiomes based on the idea that both the experiment and the model are stochastic. Starting from a stochastic model, we derive dynamical equations not only for the average, but also for higher statistical moments of the microbial abundances. We use these equations to infer distributions of the interaction parameters that best describe the biological experimental data—improving identifiability and precision. The inferred distributions allow us to make predictions but also to distinguish between fairly certain parameters and those for which the available experimental data does not give sufficient information. Compared to related approaches, we derive expressions that also work for the relative abundance of microbes, enabling us to use conventional metagenome data, and account for cases where not a single host, but only replicate hosts, can be tracked over time. -
The human posterior parietal cortices orthogonalize the representation of different streams of information concurrently coded in visual working memory
by Yaoda Xu
The key to adaptive visual processing lies in the ability to maintain goal-directed visual representation in the face of distraction. In visual working memory (VWM), distraction may come from the coding of distractors or other concurrently retained targets. This fMRI study reveals a common representational geometry that our brain uses to combat both types of distractions in VWM. Specifically, using fMRI pattern decoding, the human posterior parietal cortex is shown to orthogonalize the representations of different streams of information concurrently coded in VWM, whether they are targets and distractors, or different targets concurrently held in VWM. The latter is also seen in the human occipitotemporal cortex. Such a representational geometry provides an elegant and simple solution to enable independent information readout, effectively combating distraction from the different streams of information, while accommodating their concurrent representations. This representational scheme differs from mechanisms that actively suppress or block the encoding of distractors to reduce interference. It is likely a general neural representational principle that supports our ability to represent information beyond VWM in other situations where multiple streams of visual information are tracked and processed simultaneously. -
Turnover of retroelements and satellite DNA drives centromere reorganization over short evolutionary timescales in <i>Drosophila</i>
by Cécile Courret, Lucas W. Hemmer, Xiaolu Wei, Prachi D. Patel, Bryce J. Chabot, Nicholas J. Fuda, Xuewen Geng, Ching-Ho Chang, Barbara G. Mellone, Amanda M. Larracuente
Centromeres reside in rapidly evolving, repeat-rich genomic regions, despite their essential function in chromosome segregation. Across organisms, centromeres are rich in selfish genetic elements such as transposable elements and satellite DNAs that can bias their transmission through meiosis. However, these elements still need to cooperate at some level and contribute to, or avoid interfering with, centromere function. To gain insight into the balance between conflict and cooperation at centromeric DNA, we take advantage of the close evolutionary relationships within the Drosophila simulans clade—D. simulans, D. sechellia, and D. mauritiana—and their relative, D. melanogaster. Using chromatin profiling combined with high-resolution fluorescence in situ hybridization on stretched chromatin fibers, we characterize all centromeres across these species. We discovered dramatic centromere reorganization involving recurrent shifts between retroelements and satellite DNAs over short evolutionary timescales. We also reveal the recent origin (<240 Kya) of telocentric chromosomes in D. sechellia, where the X and fourth centromeres now sit on telomere-specific retroelements. Finally, the Y chromosome centromeres, which are the only chromosomes that do not experience female meiosis, do not show dynamic cycling between satDNA and TEs. The patterns of rapid centromere turnover in these species are consistent with genetic conflicts in the female germline and have implications for centromeric DNA function and karyotype evolution. Regardless of the evolutionary forces driving this turnover, the rapid reorganization of centromeric sequences over short evolutionary timescales highlights their potential as hotspots for evolutionary innovation. -
Correction: Dog–human vocal interactions match dogs’ sensory-motor tuning
by Eloïse C. Déaux, Théophane Piette, Florence Gaunet, Thierry Legou, Luc Arnal, Anne-Lise Giraud