Illuminating complexity in serotonin neurons of the dorsal raphe nucleus.

The function of serotonin in the mammalian brain has been challenging to unravel. In this issue of Neuron, Paquelet et al. (2022) employ microendoscopy to record over 2,000 dorsal raphe serotonin neurons, yielding new insights into their activity from the single neuron to the population level.

Reward expectation differentially modulates attentional behavior and activity in visual area V4.

Neural activity in visual area V4 is enhanced when attention is directed into neuronal receptive fields. However, the source of this enhancement is unclear, as most physiological studies have manipulated attention by changing the absolute reward associated with a particular location as well as its value relative to other locations. We trained monkeys to discriminate the orientation of two stimuli presented simultaneously in different hemifields while we independently varied the reward magnitude associated with correct discrimination at each location.

Cytokinetic furrowing in toroidal, binucleate and anucleate cells in C. elegans embryos.

Classical experimental studies on echinoderm zygotes concluded that the juxtaposition of two astral microtubule arrays localizes the stimulus for cytokinetic furrowing. However, recent experimental and genetic studies in Caenorhabditis elegans, Drosophila and mammalian cultured cells implicate microtubules of the central spindle, and regulatory proteins associated with this structure, suggesting that the essential conditions for furrow induction may differ from one animal cell to another. We used micromanipulation and laser microsurgery to create, in three ways, the juxtaposition of astral microtubules in C.

Chromosome 22q11 microdeletion and congenital heart disease--a survey in a paediatric population.

Unlabelled: Congenital heart disease is a common finding in patients with microdeletion of chromosome 22q11. To determine if the deletion is an epidemiologically important cause of congenital heart disease, we studied a consecutive series of children attending a paediatric cardiac clinic and of neonates diagnosed as having structural congenital heart disease. Venous blood samples were tested by fluorescent in-situ hybridisation analysis for microdeletion of chromosome 22q11 using probe D22S75.