Social cognition

The V1a vasopressin receptor is necessary and sufficient for normal social recognition: a gene replacement study.Bielsky, I. F. et al. Neuron 47, 503–513 (2005)

A deficiency in the vasopressin receptor V1aR in mice has important consequences for social recognition and anxiety-related behaviour. Both the lateral septum and the medial amygdala have been implicated in these behaviours. In this study, V1aR antagonists in wild-type mice led to social impairments when targeted to the lateral septum but not the medial amygdala. Moreover, re-expressing V1aR in the lateral septum of mice deficient in V1aR led to complete rescue of social recognition behaviours, confirming a crucial role for this region in complex social behaviour.

Neurological disorders

Amyloid precursor protein promotes post-developmental neurite arborization in the Drosophila brain.Leyssen, M. et al. EMBO J. 24, 2944–2955 (2005)

Amyloid precursor protein (APP) is well known to be involved in the pathogenesis of Alzheimer's disease. Studies of the expression of human and Drosophila forms of APP in the Drosophila brain now provide clues that APP is also important for axonal outgrowth in the adult but not in the developing brain, and that increased expression of APP is triggered specifically in response to traumatic brain injury.

Glia

Synaptic transmission onto hippocampal glial cells with hGFAP promoter activity.Jabs, R. et al. J. Cell Sci. 118, 3791–3803 (2005)

There is growing evidence that glial cells work as communication elements in the brain. Now, a distinct type of glial cell in the hippocampus — dubbed the GluR cell — has been shown in mice to have synapse-like structures. The researchers present the first evidence that these cells receive both stimulus-correlated and spontaneous GABA (γ-aminobutyric acid)- and glutamate-mediated input, thereby revealing novel signalling mechanisms between neurons and glia.

Development

The Notch ligands DLL1 and JAG2 act synergistically to regulate hair cell development in the mammalian inner ear.Kiernan, A. E. et al. Development 132, 4353–4362 (2005)

The number of sensory hair cells that form in the organ of Corti in the mammalian inner ear is thought to be regulated by Notch signalling. In mouse embryos, two Notch ligands — Dll1 and Jag2 — seemed to interact synergistically to regulate hair cell differentiation in the cochlea. Results indicated that Notch pathways acted through both lateral inhibition — when a cell differentiating as one type prevents neighbouring cells from differentiating to the same type — and the control of cell proliferation levels.