Ion channels

Structural basis for modulation and agonist specificity of HCN pacemaker channels. Zagotta, W. N. et al. Nature 425, 200–205 (2003)

HCN channels have pacemaking activity in heart and brain cells, are activated by hyperpolarization, and are modulated by cyclic nucleotides. On the basis of crystallographic and equilibrium sedimentation analyses of the carboxy-terminal domain of HCN2, Zagotta and colleagues define the mechanism of cyclic nucleotide specificity and identify a domain that mediates the tetramerization of this channel region. They also propose a possible mechanism for the allosteric modulation of gating. These results might be relevant to other cyclic nucleotide-binding channels.

Sensory systems

Multiple actions of systemic artemin in experimental neuropathy. Gardell, R. L. et al. Nature Med. 5 October 2003 (doi: 10.1038/nm944)

Neuropathic pain — pain caused by functional disturbances of peripheral nerves — can be successfully treated with systemic artemin in rats, according to this study. Artemin is a member of the glial-derived neurotrophic factor family, and the peripheral expression of its receptor — GFRα3 — is restricted to nociceptive neurons. The authors found that artemin reversed several behavioural, morphological and biochemical correlates of experimental neuropathy with no obvious side effects, pointing to its possible therapeutic use.

Cognitive neuroscience

Sounds and silence: an optical topography study of language recognition at birth. Peña, M. et al. Proc. Natl Acad. Sci. USA 100, 11702–11705 (2003)

Newborn infants can organize the auditory world. Winkler, I. et al. Proc. Natl Acad. Sci. USA 100, 11812–11815 (2003)

Our understanding of the cognitive abilities and organization of newborn infants suffers from difficulties in applying traditional techniques of study to babies. In these two papers, different techniques are applied to show that the responses of newborn infants to auditory stimuli are similar to those of adults. In the first, Peña et al. use optical topography — an optical technique for imaging changes in blood flow in the cortex below the scalp — to show that, even in babies that are just two or three days old, the left hemisphere responds preferentially to speech, but not to backward speech. In the second study, Winkler and colleagues use the mismatch negativity — an electroencephalogram signal that is a signature for the detection of an 'oddball' stimulus — to show that similarly young infants can also segregate concurrent streams of sound according to their source. As in adults, the segregation of the sounds depends on a difference in spatial pitch between the two streams.