Formation of presynaptic terminals at predefined sites along axons. Sabo, S. L., Gomes, R. A. & McAllister, A. K. J. Neurosci. 26, 10813–10825 (2006)
The factors that determine the position along an axon at which synapses form and how synaptic proteins accumulate at these sites are unknown. In this study, time-lapse imaging of synaptic vesicle protein transport vesicles (STVs) in rat cortical neurons showed that their accumulation and the formation of presynaptic terminals induced by neuroligin-expressing non-neuronal cells occurred only at particular predefined sites in the axon. Furthermore, the authors found that, even in axons that have no contact with neurons or glia, STVs repeatedly pause at these specific locations.
Toll-like receptor 8 functions as a negative regulator of neurite outgrowth and inducer of neuronal apoptosis. Ma, Y. et al. J. Cell Biol. 175, 209–215 (2006)
Toll-like receptors (TLRs) are essential for innate and adaptive immunity and have also been shown to be expressed in neurons, although their function in this cell type remains undetermined. The authors show that agonist stimulation of TLR8, which localizes to neurons and axons during mouse brain development, inhibits neurite outgrowth and induces apoptosis in cultured neurons, suggesting functions for TLRs distinct from their classical role in immunity. Unlike the effects of TLR8 in immune cells, these neuronal responses do not seem to involve the TLR–NF-κB pathway.
Although neuregulin 1 (NRG1) has been associated with schizophrenia, no specific functional mutation associated with the disease has previously been found. The effects of a variant in the NRG1 promoter region were studied in patients with a high risk of schizophrenia, showing an association between the variant and decreased activity in frontal and temporal lobe regions, the development of psychotic symptoms, and decreased premorbid IQ.
Variations in the human pain stress experience mediated by ventral and dorsal basal ganglia dopamine activity. Scott, D. J. et al. J. Neurosci. 26, 10789–10795 (2006)
The basal ganglia have roles in motor control and reward mechanisms. There is also growing evidence that dopaminergic pathways in the basal ganglia are involved in responses to stress and aversive stimuli. The authors used positron emission tomography with the dopamine D2 receptor antagonist radiotracer [11C]raclopride to show that the dopamine D2 system is activated in response to a painful stimulus in humans, and that this involves both dorsal and ventral basal ganglia regions.
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In Brief. Nat Rev Neurosci 7, 906 (2006). https://doi.org/10.1038/nrn2050