New methods are emerging that aim to image chemical reactions as they occur using X-ray diffraction, electron diffraction or laser-induced recollision, but spectral selection cannot be used to monitor the reacting molecules for these methods. These authors show that this apparent limitation offers opportunities for recollision-based high-harmonic spectroscopy, in which unexcited molecules can act as local oscillators against which structural and electronic dynamics is observed on an attosecond timescale.

Birds and mammals have distinct sex chromosomes: in birds, males are ZZ and females ZW; in mammals, males are XY and females XX. By sequencing the chicken Z chromosome and comparing it with the human X chromosome, these authors overturn the currently held view that these chromosomes have diverged little from their autosomal progenitors. The Z and X chromosomes seem to have followed convergent evolutionary trajectories, despite evolving with opposite systems of heterogamety.

It has long been thought that motor control is achieved through the balanced activity of two distinct pathways througthe basal ganglia that have opposing effects, but this has never been functionally verified. These authors directly test this hypothesis with optogenetic activation of different populations of mouse striatal neurons, and not only trace functional connectivity but demonstrate opposing effects on motor behaviour in a parkinsonian model.