Science 2 May 2008:
Vol. 320. no. 5876, pp. 630 - 634
A Specialized Forebrain Circuit for Vocal Babbling in the Juvenile Songbird
Young animals engage in variable exploratory behaviors essential for the development of neural circuitry and adult motor control, yet the neural basis of these behaviors is largely unknown. Juvenile songbirds produce subsong—a succession of primitive vocalizations akin to human babbling. We found that subsong production in zebra finches does not require HVC (high vocal center), a key premotor area for singing in adult birds, but does require LMAN (lateral magnocellular nucleus of the nidopallium), a forebrain nucleus involved in learning but not in adult singing. During babbling, neurons in LMAN exhibited premotor correlations to vocal output on a fast time scale. Thus, juvenile singing is driven by a circuit distinct from that which produces the adult behavior—a separation possibly general to other developing motor systems.

Nature 453, 41-42 (1 May 2008) | doi:10.1038/453041a; Published online 30 April 2008
Neuroscience: Hidden female talent
A male fruitfly serenades his female with a courtship song produced by vibrating one wing. The female also has the neuronal circuitry to generate a song of her own, but her brain tells her not to.
Male flies tend to put on quite a show when it comes to sex. They have to.

Nature 453, 102-105 (1 May 2008) | doi:10.1038/nature06829; Received 11 July 2007; Accepted 7 February 2008; Published online 23 April 2008
Melanopsin cells are the principal conduits for rod–cone input to non-image-forming vision
Rod and cone photoreceptors detect light and relay this information through a multisynaptic pathway to the brain by means of retinal ganglion cells (RGCs). These retinal outputs support not only pattern vision but also non-image-forming (NIF) functions, which include circadian photoentrainment and pupillary light reflex (PLR). In mammals, NIF functions are mediated by rods, cones and the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). Rod–cone photoreceptors and ipRGCs are complementary in signalling light intensity for NIF functions. The ipRGCs, in addition to being directly photosensitive, also receive synaptic input from rod–cone networks. To determine how the ipRGCs relay rod–cone light information for both image-forming and non-image-forming functions, we genetically ablated ipRGCs in mice. Here we show that animals lacking ipRGCs retain pattern vision but have deficits in both PLR and circadian photoentrainment that are more extensive than those observed in melanopsin knockouts. The defects in PLR and photoentrainment resemble those observed in animals that lack phototransduction in all three photoreceptor classes. These results indicate that light signals for irradiance detection are dissociated from pattern vision at the retinal ganglion cell level, and animals that cannot detect light for NIF functions are still capable of image formation.

NEJM Volume 358:1951  May 1, 2008  Number 18
Changes in the Brain Stem and Fundus in Malignant Hypertension
A 53-year-old man presented with a 4-week history of bilateral retrobulbar headache and blurred vision. His blood pressure was 220/135 mm Hg; his neurologic examination was unremarkable. He had no history of hypertension and was not taking any medication for its treatment. Fundus examination showed bilateral disk edema, lipid exudate, cotton-wool spots,  a swollen optic nerve, and retinal hemorrhages. Magnetic resonance imaging of the brain showed an isolated hyperintense abnormality on fluid-attenuated inversion recovery (FLAIR) images in the pons and midbrain that did not enhance with gadolinium. Good control of blood pressure was established, and the appearance of the fundus and brain stem returned to normal
4 months later.