Dendritic axon origin enables information gating by perisomatic inhibition in pyramidal neurons.

Information processing in neuronal networks involves the recruitment of selected neurons into coordinated spatiotemporal activity patterns. This sparse activation results from widespread synaptic inhibition in conjunction with neuron-specific synaptic excitation. We report the selective recruitment of hippocampal pyramidal cells into patterned network activity. During ripple oscillations in awake mice, spiking is much more likely in cells in which the axon originates from a basal dendrite rather than from the soma. High-resolution recordings in vitro and computer modeling indicate that these spikes are elicited by synaptic input to the axon-carrying dendrite and thus escape perisomatic inhibition. Pyramidal cells with somatic axon origin can be activated during ripple oscillations by blocking their somatic inhibition. The recruitment of neurons into active ensembles is thus determined by axonal morphological features.

Expression and putative functions of GDF-15, a member of the TGF-beta superfamily, in human glioma and glioblastoma cell lines.

Recent studies have demonstrated growth-inhibiting effects of growth differentiation factor-15 (GDF-15) on different cancer cell lines invitro and on tumor growth in vivo. Here, we present data concerning expression of GDF-15 in glioblastoma. We found low levels of GDF-15 transcripts in primary glioblastoma. Thus, GDF-15 expression might be exploited as a useful indicator for distinguishing primary from other glial derived tumors. In contrast to the documented proapoptotic and anti-tumorigenic activities of GDF-15 in several cancer cell lines, our data suggest that GDF-15 does not decrease proliferation of glioblastoma cell lines, while its effects on invasiveness are not consistent.