Distribution of bursting neurons in the CA1 region and the subiculum of the rat hippocampus.

We performed patch-clamp recordings from morphologically identified and anatomically mapped pyramidal neurons of the ventral hippocampus to test the hypothesis that bursting neurons are distributed on a gradient from the CA2/CA1 border (proximal) through the subiculum (distal), with more bursting observed at distal locations. We find that the well-defined morphological boundaries between the hippocampal subregions CA1 and subiculum do not correspond to abrupt changes in electrophysiological properties. Rather, we observed that the percentage of bursting neurons is linearly correlated with position in the proximal-distal axis across the CA1 and the subiculum, the percentages of bursting neurons being 10% near the CA1-CA2 border, 24% at the CA1-subiculum border, and higher than 50% in the distal subiculum.

Isolation of rat telencephalic neural explants to assay Shh GABAergic interneuron differentiation-inducing activity.

Multiple assays for Shh activity using cell lines, primary cultures, and explanted tissue have been described. We first described the use of E11.5 rat dorsal telencephalic explants to assay Shh ventralizing and differentiation-inducing activity in Kohtz et al.

The Evf-2 noncoding RNA is transcribed from the Dlx-5/6 ultraconserved region and functions as a Dlx-2 transcriptional coactivator.

The identification of ultraconserved noncoding sequences in vertebrates has been associated with developmental regulators and DNA-binding proteins. One of the first of these was identified in the intergenic region between the Dlx-5 and Dlx-6 genes, members of the Dlx/dll homeodomain-containing protein family. In previous experiments, we showed that Sonic hedgehog treatment of forebrain neural explants results in the activation of Dlx-2 and the novel noncoding RNA (ncRNA), Evf-1.